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  • Ultrastructure  (1,615)
  • Immunocytochemistry  (856)
  • Springer  (2,440)
  • 1
    Electronic Resource
    Electronic Resource
    Glomus claroideum forms an arbuscular mycorrhiza-like symbiosis with the hornwort Anthoceros punctatus (2000)
    Springer
    Mycorrhiza 10 (2000), S. 15-21 
    Details
    ISSN: 1432-1890
    Keywords: Anthoceros punctatus ; Arbuscular mycorrhiza ; Bryophytes ; Glomus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Glomus claroideum (Schenck & Smith emend. Walker & Vestberg) were investigated for ability to form arbuscular mycorrhiza-like symbioses with the hornwort Anthoceros punctatus (L.). Spores were transferred to a cellulose acetate filter on water agar and a small portion of an Anthoceros thallus was placed directly upon the spores. Light-microscope observations 20 days after inoculation revealed branched hyphae growing within the thallus. After 45 days, arbuscules and vesicles were studied by light- and electron-microscopy. After 60 days in water agar culture, the colonised Anthoceros thalli were transferred to a low-nutrient medium agar. Hyphae spread in the agar and newly formed spores were observed 5 weeks after the transfer. After 4 months, about 1000 spores were formed in each Petri dish. This is the first report of an experimentally established arbuscular mycorrhiza-like symbiosis between an identified fungus belonging to the Glomales and a bryophyte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s005720050282
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  • 2
    Electronic Resource
    Electronic Resource
    The need for speed. II. Myelin in calanoid copepods (2000)
    Springer
    Journal of comparative physiology 186 (2000), S. 347-357 
    Details
    ISSN: 1432-1351
    Keywords: Key words Crustacean ; Sensorimotor ; Ultrastructure ; Multilamellar sheath ; Myelinated axons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Speed of nerve impulse conduction is greatly increased by myelin, a multi-layered membranous sheath surrounding axons. Myelinated axons are ubiquitous among the vertebrates, but relatively rare among invertebrates. Electron microscopy of calanoid copepods using rapid cryofixation techniques revealed the widespread presence of myelinated axons. Myelin sheaths of up to 60 layers were found around both sensory and motor axons of the first antenna and interneurons of the ventral nerve cord. Except at nodes, individual lamellae appeared to be continuous and circular, without seams, as opposed to the spiral structure of vertebrate and annelid myelin. The highly organized myelin was characterized by the complete exclusion of cytoplasm from the intracellular spaces of the cell generating it. In regions of compaction, extracytoplasmic space was also eliminated. Focal or fenestration nodes, rather than circumferential ones, were locally common. Myelin lamellae terminated in stepwise fashion at these nodes, appearing to fuse with the axolemma or adjacent myelin lamellae. As with vertebrate myelin, copepod sheaths are designed to minimize both resistive and capacitive current flow through the internodal membrane, greatly speeding nerve impulse conduction. Copepod myelin differs from that of any other group described, while sharing features of every group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003590050435
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  • 3
    Electronic Resource
    Electronic Resource
    Structural changes during early embryogenesis in wheat pollen (2000)
    Springer
    Protoplasma 211 (2000), S. 94-102 
    Details
    ISSN: 1615-6102
    Keywords: Androgenesis ; Embryogenesis ; Microspore culture ; Pollen ; Ultrastructure ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We have made a detailed cytological examination of the development of wheat embryoids, monitoring their initial divisions from two to ten cells by both light and electron microscopy. According to our observations the first embryogenic division is symmetrical. After the androgenesis induction treatment, there is a decrease in ribosome population with cells that have inactive nucleoli made up almost exclusively of a dense fibrillar component. This population is restored after initial embryogenic divisions. During the initial divisions the embryogenic pollen grains do not appear to change in size and the pollen wall remains intact. The exine undergoes no modification but the intine thickens, and we have observed that the thickness of the intine can be used as a cytological marker of androgenesis. The walls separating the cells obtained after embryogenic division contained numerous plasmodesmata. The beginnings of embryo polarization and cell differentiation could be made out in the very early pollen embryoids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279902
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of glutathione on thiol redox systems, chromosomal aberrations, and the ultrastructure of meristematic root cells ofPicea abies (L.) Karst. (2000)
    Springer
    Protoplasma 212 (2000), S. 227-235 
    Details
    ISSN: 1615-6102
    Keywords: Glutathione ; Root ; Chromosomal aberration ; Ultrastructure ; Picea abies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Young spruce seedlings (Picea abies [L.] Karst.) grown in hydroponic culture were exposed to three different concentrations (50,100, and 500 μM) of reduced glutathione for 24 h. These physiologically relevant concentrations of glutathione had a multiple effect on the investigated tissue. Feeding of glutathione to roots increased the concentrations of thiols (glutathione, cysteine, and γ-glutamyl-cysteine) in roots, decreased the rate of cell divisions, induced mitotic abnormalities, and affected the cell ultrastructure. Electron micrographs showed effects such as advanced vacuolation, dilated rough-endoplasmic-reticulum cisternae, and separations of the plasma membrane from the cell wall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01282923
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  • 5
    Electronic Resource
    Electronic Resource
    Calcium-binding Proteins Calbindin D28K, Calretinin, and Parvalbumin Immunoreactivity in the Rabbit Visual Cortex (2000)
    Springer
    Molecules and cells 10 (2000), S. 206-212 
    Details
    ISSN: 0219-1032
    Keywords: Calcium-binding Protein ; Immunocytochemistry ; Localization ; Visual Cortex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The distribution and morphology of neurons containing three calcium-binding proteins, calbindin D28K, calretinin, and parvalbumin in the adult rabbit visual cortex were studied. The calcium-binding proteins were identified using antibody immunocytochemistry. Calbindin D28K-immunoreactive (IR) neurons were located throughout the cortical layers with the highest density in layer V. However, calbindin D28K-IR neurons were rarely encountered in layer I. Calretinin-IR neurons were mainly located in layers II and III. Considerably lower densities of calretinin-IR neurons were observed in the other layers. Parvalbumin-IR neurons were predominantly located in layers III, IV, V, and VI. In layers I and II, parvalbumin-IR neurons were only rarely seen. The majority of the calbindin D28K-IR neurons were stellate, round or oval cells with multipolar dendrites. The majority of calretinin-IR neurons were vertical fusiform cells with long processes traveling perpendicularly to the pial surface. The morphology of the majority of parvalbumin-IR neurons was similar to that of calbindin D28K: stellate, round or oval with multipolar dendrites. These results indicate that these three different calcium-binding proteins are contained in specific layers and cells in the rabbit visual cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10059-000-0206-2
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  • 6
    Electronic Resource
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    Ultrastructure and anatomy of nematode-induced syncytia in roots of susceptible and resistant sugar beet (2000)
    Springer
    Protoplasma 211 (2000), S. 39-50 
    Details
    ISSN: 1615-6102
    Keywords: Beta vulgaris ; Cyst nematodes ; Histology ; Resistance mechanism ; Syncytium ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using susceptible and resistant sugar beet lines, comparative analyses of root histology and ultrastructure were made during invasion by nematodes and the induction and formation of specific feeding structures (syncytia).The resistant line carried the resistance geneHs1pro−1.Nematodes were able to invade and induce functional syncytia in roots of resistant and susceptible lines. However, syncytia in resistant roots were smaller and less hypertrophied. The vacuolar system of syncytia in susceptible plants contained many small vacuoles. In resistant plants vacuoles were larger but less numerous. Smooth endoplasmic reticulum prevailed in syncytial protoplasts of susceptible plants, whereas almost only rough endoplasmic reticulum occurred in syncytia in resistant plants. The most conspicuous and hitherto undescribed trait of syncytia in resistant roots was the initial appearance of loose, and later compact, aggregations of the endomembrane system which composed most of the endoplasmicreticulum system of syncytia at later stages. Syncytia in resistant plants usually degraded before the nematodes reached their adult stage. The appearance of membrane aggregations and the other resistance-specific features are discussed in relation to their possible effects on syncytium function and role in nematode resistance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279898
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  • 7
    Electronic Resource
    Electronic Resource
    Immunocytochemical characterization of early-developing flax fiber cell walls (2000)
    Springer
    Protoplasma 213 (2000), S. 235-245 
    Details
    ISSN: 1615-6102
    Keywords: Arabinogalactan proteins ; Fiber ; Linum usitatissimum ; Immunocytochemistry ; Polysaccharide ; Secondary wall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The deposition and formation of a thick secondary wall is a major event in the differentiation of flax (Linum usitatissimum) fibers. This wall is cellulose-rich; but it also contains significant amounts of other matrix polymers which are noncellulosic such as pectins. We have used immunocytochemical techniques with antibodies specific for various epitopes associated with either pectins or arabinogalactan proteins (AGPs) to investigate the distribution of these polymers within the walls of differentiating young fibers of 1- and 2-week-old plants. Our results show that different epitopes exhibit distinct distribution patterns within fiber walls. Unesterified pectins recognized by polygalacturonic acid-rhamnogalacturonan I (PGA/RG-I) antibodies and rhamnogalacturonan II recognized by anti-RG-II-borate complex antibodies are localized all over the secondary wall of fibers. PGA/RG-I epitopes, but not RG-II epitopes, are also present in the middle lamellae and cell junctions. In marked contrast, β-(1→4) galactans recognized by the LM5 monoclonal antibody and AGP epitopes recognized by anti-β-(1→6) galactan and LM2 antibodies are primarily located in the half of the secondary wall nearest the plasma membrane. LM2 epitopes, present in 1-week-old fibers, are undetectable later in development, suggesting a regulation of the expression of certain AGP epitopes. In addition, localization of cellulose with the cellobiohydrolase I-gold probe reveals distinct subdomains within the secondary walls of young fibers. These findings indicate that, in addition to cellulose, early-developing flax fibers synthesize and secrete different pectin and AGP molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01282161
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  • 8
    Electronic Resource
    Electronic Resource
    Effect of osmotic stress on tolerance of air-drying and cryopreservation ofArabidopsis thaliana suspension cells (2000)
    Springer
    Protoplasma 214 (2000), S. 227-243 
    Details
    ISSN: 1615-6102
    Keywords: Arabidopsis thaliana ; Cryopreservation ; Dehydration ; Thermal analysis ; Sucrose ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Arabidopsis thaliana suspension cells were preserved in liquid nitrogen for over three years, using embedding of cells in calcium-alginate prior to subculture in sucrose-enriched medium, air-drying, and direct quenching in liquid nitrogen. Survival of cells reached 34%, yielding regrowth at the surface of all cryopreserved beads in less than 7 days. Following pretreatment and dehydration, the water content dropped from 2300% to 34% with respect to dry weight. Differential scanning calorimetry showed that glass transition occurred on cooling, followed by a slight crystallization event on rewarming. The survival of cells was independent of the cooling rate. The tolerance of the acute dehydration step increased progressively with sucrose pretreatment duration, indicating the requirement for adaptative cellular alterations. Ultrastructural studies revealed several changes in cells after sucrose pretreatment prolonged from 1 to 7 days: reversal of the initially plasmolyzed state, microvacuolation, numerous autophagic structures, scarcity of ribosomes, increase in number and size of starch grains. No cell division seemed to occur during this period. After air-drying and after a freeze-thaw cycle, followed by 24 h rehydration, regenerating cells had recovered a high level of ultrastructural organization and contained numerous polysomes suggesting an intense metabolic activity. Trehalose, a cryoprotective disaccharide not considered to be a metabolic substrate, yielded only 70% regrowth after freezing. Biochemical analysis showed that soluble sugars accumulated during the pretreatment, essentially sucrose or trehalose; the monosaccharide content also increased. In the light of these results, the action of sucrose in inducing freezing tolerance is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279067
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  • 9
    Electronic Resource
    Electronic Resource
    Larva-adult relationships in an ancestral dipteran: A re-examination of sensillar pathways across the antenna and leg anlagen of Chaoborus crystallinus (DeGeer, 1776; Chaoboridae) (1999)
    Springer
    Development genes and evolution 209 (1999), S. 103-112 
    Details
    ISSN: 1432-041X
    Keywords: Key words Imaginal disc ; Axonal trajectories ; Ultrastructure ; Chaoborus (Insecta ; Diptera)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  In one of his classical studies on insect metamorphosis, Weismann compared the imaginal anlagen of the ancestral phantom midge, Chaoborus, with those of advanced brachycerans. We have expanded his findings on the relationships between larval and imaginal organs using electron microscopy and cobalt backfilling of the antenna and leg anlagen and the axonal trajectories of corresponding larval sensilla. We show that both primordia are confluent with the larval antennae and ”leg” sensilla (an ancestral Keilin organ), respectively. These fully developed larval organs represent the distal tips of the imaginal anlagen rather than separate cell clusters. The axons of the larval antenna and leg sensilla project across the corresponding anlagen to their target neuromeres within the central nervous system (CNS). Within the discs, nerves composed of these larval axons, developing afferent fibres and efferences ascending from the CNS are found. Both the structure of the primordia and the axonal trajectories thus relate the situation found in advanced brachycerans with that seen in more ancestral insects. In addition, the larval antennae, legs, wings and even the eyes possess very similar afferent pioneer trajectories supporting the idea that the described pattern is generally used in the ontogeny of sensory systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004270050232
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  • 10
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    Electronic Resource
    Isolation and characterization of a Clostridium sp. with cinnamoyl esterase activity and unusual cell envelope ultrastructure (1999)
    Springer
    Archives of microbiology 172 (1999), S. 139-149 
    Details
    ISSN: 1432-072X
    Keywords: Key wordsClostridium xylanolyticum ; Cinnamic acid ; Esterase ; Lignocellulose ; Sporogenesis ; Ultrastructure ; Cell envelope
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microorganisms that hydrolyse the ester linkages between phenolic acids and polysaccharides in plant cell walls are potential sources of enzymes for the degradation of lignocellulosic waste. An anaerobic, mesophilic, spore-forming, xylanolytic bacterium with high hydroxy cinnamic acid esterase activity was isolated from the gut of the grass-eating termite Tumilitermes pastinator. The bacterium was motile and rod-shaped, stained gram-positive, had an eight-layered cell envelope, and formed endospores. Phylogenetic analysis based on 16S rRNA indicated that the bacterium is closely related to Clostridium xylanolyticum and is grouped with polysaccharolytic strains of clostridia. A wide range of carbohydrates were fermented, and growth was stimulated by either xylan or cellobiose as substrates. The bacterium hydrolysed and then hydrogenated the hydroxy cinnamic acids (ferulic and p-coumaric acids), which are esterified to arabinoxylan in plant cell walls. Three cytoplasmic enzymes with hydroxy cinnamic acid esterase activity were identified using non-denaturing gel electrophoresis. This bacterium possesses an unusual multilayered cell envelope in which both leaflets of the cytoplasmic membrane, the peptidoglycan layer and the S layer are clearly discernible. The fate of all these components was easily followed throughout the endospore formation process. The peptidoglycan component persisted during the entire morphogenesis. It was seen to enter the septum and to pass with the engulfing membranes to surround the prespore. It eventually expanded to form the cortex, verification for the peptidoglycan origin of the cortex. Sporogenic vesicles, which are derived from the cell wall peptidoglycan, were associated with the engulfment process. Spore coat fragments appeared early, in stage II, though spore coat formation was not complete until after cortex formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050753
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  • 11
    Electronic Resource
    Electronic Resource
    Cambium: old challenges – new opportunities (1999)
    Springer
    Trees 13 (1999), S. 138-151 
    Details
    ISSN: 0931-1890
    Keywords: Key words Cytoskeleton ; Immunocytochemistry ; Model systems ; Populus ; Secondary vascular system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Trees represent a, probably the, major component of the biosphere and have a unique place in the history of Mankind. One of their most fascinating features is the process of secondary growth which is effected principally by the secondary vascular system, the developmental continuum of secondary phloem, vascular cambium, and secondary xylem. However, for too long assumptions about the developmental biology of trees have had to be based upon studies of primary growth systems within annual, herbaceous species because study of the secondary vascular system had been largely ignored. Even when attempts are made to understand some of the most fundamental features of the secondary vascular system, such as xylogenesis, the current model system, isolated Zinnia mesophyll cells, is not entirely appropriate to the situation in the intact tree. Some deficiencies of the Zinnia system are discussed, and the advantages of the genus Populus as a model for study of the hardwood secondary vascular system are considered. Some of the new approaches which are poised to lead to significant advances in our knowledge of the cell bio-logy of the secondary vascular system of trees – spe-cifically of the cell wall, the plasmalemma, and the cytoskeleton – are discussed. The value of one of these new techniques – immunocytochemistry – is demonstrated by a consideration of recent work on the role of the cytoskeleton in the hardwood secondary vascular system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00009745
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  • 12
    Electronic Resource
    Electronic Resource
    Megasporogenesis in Arabidopsis thaliana L.: an ultrastructural study (1999)
    Springer
    Sexual plant reproduction 12 (1999), S. 99-109 
    Details
    ISSN: 1432-2145
    Keywords: Key words Arabidopsis thaliana ; Megasporogenesis ; Meiosis ; Ultrastructure ; Cellular polarity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  In this study, megasporogenesis of the plant model Arabidopsis thaliana was investigated by electron microscopy for the first time. The data described here could constitute a reference for future investigations of Arabidopsis mutants. During the beginning of meiosis the megaspore mother cell shows a polarity created by unequal distribution of organelles in the cytoplasm. Plastids accumulate in the chalazal region and long parallel saccules of endoplasmic reticulum, small vacuoles and some dictyosomes are found in the micropylar region. Plasmodesmata are abundant in the chalazal cell wall. The nucleus is almost centrally localized and contains a prominent excentric nucleolus and numerous typical synaptonemal complexes. After the second division of meiosis the four megaspores are separated by thin cell walls crossed by numerous plasmodesmata and do not show significant cellular organization. The young functional megaspore is characterized by a large nucleus and a large granular nucleolus. The cytoplasm is very electron dense due to the abundance of free ribosomes and contains the following randomly distributed organelles: mitochondria, a few short saccules of endoplasmic reticulum, dictyosomes and undifferentiated plastids. However, there is no apparent polarity, except for the distribution of some small vacuoles which are more abundant in the micropylar region of the cell. The degenerating megaspores are extremely electron dense and do not show any substructure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004970050178
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  • 13
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    Electronic Resource
    Caveolin and its cellular and subcellular immunolocalisation in lung alveolar epithelium: implications for alveolar epithelial type I cell function (1999)
    Springer
    Cell & tissue research 295 (1999), S. 111-120 
    Details
    ISSN: 1432-0878
    Keywords: Key words Caveolin ; Caveolae ; Lung ; Alveolar epithelial type I cell ; Immunocytochemistry ; Electron microscopy ; Confocal laser scanning microscopy ; Rat (CD)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Caveolae are flask-shaped invaginations of the plasmalemma which pinch off to form discrete vesicles within the cell cytoplasm. Biochemically, caveolae may be distinguished by the presence of a protein, caveolin, that is the principal component of filaments constituting their striated cytoplasmic coat. Squamous alveolar epithelial type I (ATI) cells, comprising approximately 95% of the surface area of lung alveolar epithelium, possess numerous plasmalemmal invaginations and cytoplasmic vesicles ultrastructurally indicative of caveolae. However, an ultrastructural appearance does not universally imply the biochemical presence of caveolin. This immunocytochemical study has utilised a novel application of confocal laser scanning and electron microscopy unequivocally to localise caveolin-1 to ATI cells. Further, cytoplasmic vesicles and flask-shaped membrane invaginations in the ATI cell were morphologically identified whose membranes were decorated with anti-caveolin-1 immunogold label. Coexistent with this, however, in both ATI and capillary endothelial cells could be seen membrane invaginations morphologically characteristic of caveolae, but which lacked associated caveolin immunogold label. This could reflect a true biochemical heterogeneity in populations of morphologically similar plasmalemmal invaginations or an antigen threshold requirement for labelling. The cuboidal alveolar epithelial type II cell (ATII) also displayed specific label for caveolin-1 but with no ultrastructural evidence for the formation of caveolae. The biochemical association of caveolin with ATI cell vesicles has broad implications for the assignment and further study of ATI cell function.
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    URL: http://dx.doi.org/10.1007/s004410051217
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  • 14
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    Effects of reserpine on ECL-cell ultrastructure and histamine compartmentalization in the rat stomach (1999)
    Springer
    Cell & tissue research 295 (1999), S. 131-140 
    Details
    ISSN: 1432-0878
    Keywords: Key words ECL cells ; Gastrin ; Reserpine ; Organelles ; Ultrastructure ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The histamine-storing ECL cells in the stomach play a key role in the control of acid secretion. They contain granules, secretory vesicles and microvesicles, and sustained gastrin stimulation results in the additional formation of vacuoles and lipofuscin bodies. The cells are rich in the vesicle monoamine transporter type-2 (VMAT-2), which can be inhibited by reserpine. The present study examines the effect of reserpine on ECL-cell ultrastructure and histamine compartmentalization. Rats received reserpine and/or gastrin. Reserpine was given twice by the intraperitoneal route (25 mg/kg once daily). Gastrin-17 was given by subcutaneous infusion (5 nmol/kg/h), starting at the time of the first reserpine injection and continuing for 4 days when the rats were killed. At this stage, histamine in the oxyntic mucosa was unaffected by reserpine but elevated by gastrin. Immunocytochemical analysis (confocal microscopy) showed ECL-cell histamine in control and gastrin-treated rats to be localized in cytoplasmic organelles (e.g., secretory vesicles). After treatment with reserpine alone or reserpine+gastrin, ECL-cell histamine occurred mainly in the cytosol. Planimetric analysis (electron microscopy) of ECL cells showed reserpine to increase the number, size and volume density of the granules and to reduce the size and volume density of the secretory vesicles. Gastrin reduced the number and volume density of granules and secretory vesicles, increased the number and volume density of microvesicles and caused vacuoles and lipofuscin bodies to appear. Reserpine+gastrin increased the number, volume density and size of the granules. Reserpine prevented the effects of gastrin on secretory vesicles, vacuoles and microvesicles, but did not prevent the development of lipofuscin. Our findings are in line with the views: (1) that preformed cytosolic histamine is taken up by granules/secretory vesicles via VMAT-2, that histamine is instrumental in the transformation of granules into secretory vesicles and in their consequent enlargement and (2) that vacuoles are formed by the fusion of large secretory vesicles.
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    URL: http://dx.doi.org/10.1007/s004410051219
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  • 15
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    Periviscerokinin-like immunoreactivity in the nervous system of the American cockroach (1999)
    Springer
    Cell & tissue research 295 (1999), S. 159-170 
    Details
    ISSN: 1432-0878
    Keywords: Key words Neuropeptides ; Perisympathetic organ ; Myotropin ; Visceral muscles ; Immunocytochemistry ; Insect nervous system ; Periplaneta americana (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A highly specific polyclonal antiserum has been raised against periviscerokinin, the first neuropeptide isolated from the perisympathetic organs of insects (Predel et al. 1995). In this study, two different neuronal systems with periviscerokinin-like immunoreactivity were distinguished in the central nervous system of the American cockroach: (1) An intrinsic neuronal network, restricted to the head-thoracic region, was formed by intersegmental projecting neurons of the brain, suboesophageal ganglion and metathoracic ganglion. In addition, groups of local interneurons occurred in the proto- and tritocerebrum. (2) A typical neurohormonal system was stained exclusively in the abdomen; it was represented by abdominal perisympathetic organs which were supplied by three cell clusters located in each unfused abdominal ganglion. As revealed by nickel backfills, most neurons with axons entering the perisympathetic organs contained a periviscerokinin-like peptide. Immunoreactive fibres left the perisympathetic organs peripherally, innervated the hyperneural muscle and ran via the link nerves/segmental nerves to the heart and segmental vessels. All visceral muscles innervated by periviscerokinin-immunoreactive fibres were shown to be sensitive to periviscerokinin, whereas the hindgut gave no specific response to this peptide.
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    URL: http://dx.doi.org/10.1007/s004410051222
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  • 16
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    Morphology and synaptic connectivity of nitric oxide synthase-immunoreactive neurons in the guinea pig retina (1999)
    Springer
    Cell & tissue research 297 (1999), S. 397-408 
    Details
    ISSN: 1432-0878
    Keywords: Key words Retina ; NOS ; Immunocytochemistry ; Synaptic connectivity ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Immunocytochemical methods with an antiserum against neuronal nitric oxide synthase (NOS) were applied to identify the morphology and synaptic connectivity of NOS-like immunoreactive neurons in the guinea pig retina. In the present study, two types of amacrine cells were labeled with anti-NOS antisera. Type 1 cells had large somata located in the inner nuclear layer (INL) with long, sparsely branched processes ramifying mainly in stratum 3 of the inner plexiform layer (IPL). The somata of type 2 cells (smaller diameters) were located in the INL. Some displaced amacrine cells in the ganglion cell layer were labeled. The soma size of the displaced amacrine cells was similar to that of the type 2 amacrine cells. However, processes originating from type 2 amacrine cells and displaced amacrine cells stratified mainly in strata 1 and 5, respectively. Some cone bipolar cells were weakly NOS-immunoreactive. The synaptic connectivity of NOS-like immunoreactive amacrine cells was identified in the IPL by electron microscopy. NOS-labeled amacrine cell processes received synaptic input from other amacrine cell processes and bipolar cell axon terminals in all strata of the IPL. The most frequent postsynaptic targets of NOS-immunoreactive amacrine cells were other amacrine cell processes. Cone bipolar cells were postsynaptic to NOS-labeled amacrine cells in all strata of the IPL. Labeled amacrine cells synapsing onto ganglion cells were found only in sublamina b. A few synaptic contacts were observed between labeled cell processes. In the outer plexiform layer, dendrites of labeled bipolar cells made basal contact with cone pedicles or formed a synaptic triad opposed to a synaptic ribbon of cone pedicles.
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    URL: http://dx.doi.org/10.1007/s004410051367
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  • 17
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    Pigment-dispersing hormone-like immunoreactive neurons in the central nervous system of the gastropods, Helix pomatia and Lymnaea stagnalis (1999)
    Springer
    Cell & tissue research 295 (1999), S. 339-348 
    Details
    ISSN: 1432-0878
    Keywords: Key words Pigment-dispersing hormone ; Immunocytochemistry ; Central nervous system ; Gastropoda ; Helix pomatia ; Lymnaea stagnalis (Mollusca)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract By using an antiserum raised against a crustacean β-pigment-dispersing hormone (PDH), the distribution and chemical neuroanatomy of PDH-like immunoreactive neurons was investigated in the central nervous system of the gastropod snails, Helix pomatia and Lymnaea stagnalis. The number of immunoreactive cells in the Helix central nervous system was found to be large (700–900), whereas in Lymnaea, only a limited number (50–60) of neurons showed immunoreactivity. The immunostained neurons in Helix were characterized by rich arborizations in all central ganglia and revealed massive innervation of all peripheral nerves and the neural (connective tissue) sheath around the ganglia and peripheral nerve trunks. A small number of Helix nerve cell bodies in the viscero-parietal ganglion complex were also found to be innervated by PDH-like immunoreactive processes. Hence, a complex central and peripheral regulatory role, including neurohormonal actions, is suggested for a PDH-like substance in Helix, whereas the sites of action may be more limited in Lymnaea.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410051240
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    Simultaneous apocrine and merocrine secretion in the rat coagulating gland (1999)
    Springer
    Cell & tissue research 295 (1999), S. 495-504 
    Details
    ISSN: 1432-0878
    Keywords: Key words Coagulating gland ; Apocrine secretion ; Merocrine secretion ; Immunocytochemistry ; Immunoelectron microscopy ; Scanning electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The coagulating gland of the rat synthesizes two prevalent secretory proteins (transglutaminase and 115 K) that are discharched in a different manner, one being secreted in an apocrine fashion (transglutaminase) and the other one in a merocrine way (115 K). Differences in the intra- cellular pathway and the release of either protein were studied using immunofluorescence on semithin sections, immunoelectron microscopy of preembedding-processed chopper sections and postembedding-processed ultrathin sections of rat coagulating gland. Immunohistochemical staining using an anti-transglutaminase antibody resulted in dense labeling of the cytoplasm of secretory cells and their apical blebs, whereas the cisternae of the rough endoplasmic reticulum and the Golgi apparatus were completely unlabeled. When, on the contrary, the anti-115 K antiserum was used, dense labeling of the cisternae of the rough endoplasmic reticulum, the Golgi apparatus, and the secretory granules was seen. Intraluminal secretion was also labeled, but the secretory blebs remained unlabeled. Our findings show that, in the coagulating gland of the male rat, the two secretory proteins studied are processed in parallel, but at completely different intracellular pathways. They are released via different extrusion mechanisms. Transglutaminase is synthesized outside the endoplasmic reticulum, reaches the apical cell pole by free flow in the cytoplasm, and is released via apocrine blebs, the membranes of which appear to be derived from the apical plasma membrane. The protein 115 K, on the other hand, follows the classic route, being synthesized within the cisternae of rough endoplasmic reticulum, subsequently glycosylated in the Golgi apparatus, and released in a merocrine fashion. The mutual exclusion of the two secretory pathways and the regulation of the alternative release mechanism are still unresolved issues.
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    URL: http://dx.doi.org/10.1007/s004410051255
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    Peripheral synapses at identifiable mechanosensory neurons in the spider Cupiennius salei : synapsin-like immunoreactivity (1999)
    Springer
    Cell & tissue research 295 (1999), S. 13-19 
    Details
    ISSN: 1432-0878
    Keywords: Key words Mechanoreceptors ; Synaptic proteins ; Histochemistry ; Ultrastructure ; Slit sensilla ; Hair sensilla ; Cupiennius salei (Chelicerata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Indirect immunocytochemical tests were used at the light- and electron-microscopic levels to investigate peripheral chemical synapses in identified sensory neurons of two types of cuticular mechanosensors in the spider Cupiennius salei Keys.: (1) in the lyriform slit-sense organ VS-3 (comprising 7–8 cuticular slits, each innervated by 2 bipolar sensory neurons) and (2) in tactile hair sensilla (each supplied with 3 bipolar sensory cells). All these neurons are mechanosensitive. Application of a monoclonal antibody against Drosophila synapsin revealed clear punctate immunofluorescence in whole-mount preparations of both mechanoreceptor types. The size and overall distribution of immunoreactive puncta suggested that these were labeled presynaptic sites. Immunofluorescent puncta were 0.5–6.8 μm long and located 0.5–6.6 μm apart from each other. They were concentrated at the initial axon segments of the sensory neurons, while the somata and the dendritic regions showed fewer puncta. Western blot analysis with the same synapsin antibody against samples of spider sensory hypodermis and against samples from the central nervous system revealed a characteristic doublet band at 72 kDa and 75 kDa, corresponding to the apparent molecular mass of synapsin in Drosophila and in mammals. Conventional transmissionelectron-microscopic staining demonstrated that numerous chemical synapses (with at least 2 vesicle types) were present at these mechanosensory neurons and their surrounding glial sheath. The distribution of these synapses corresponded to our immunofluorescence results.Ultrastructural examination of anti-synapsin-stained neurons confirmed that reaction product was associated with synaptic vesicles. We assume that the peripheral synaptic contacts originate from efferents that could exert a complex modulatory influence on mechanosensory activity.
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    URL: http://dx.doi.org/10.1007/s004410051208
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    Immunoultrastructural expression of intercellular adhesion molecule-1 in endothelial cell vesiculotubular structures and vesiculovacuolar organelles in blood-brain barrier development and injury (1999)
    Springer
    Cell & tissue research 295 (1999), S. 77-88 
    Details
    ISSN: 1432-0878
    Keywords: Key words Cerebrovascular development and injury ; Hemangioma ; Angiogenesis ; Immunocytochemistry ; Adhesion molecules ; Conventional transmission and high-voltage electron microscopy ; Mouse (C57BL ; SJL/J) ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Blood vessels from the vasculature of mouse brains during postnatal development and from human brain tumors (hemangiomas) removed at biopsy were examined immunocytochemically by transmission electron microscopy (TEM) or high-voltage transmission electron microscopy (HVEM) to determine the expression of intercellular adhesion molecule-1 (ICAM-1). In the mouse brains, ICAM-1 was shown to be initially expressed on the luminal and abluminal endothelial cell (EC) surfaces on day 3 after birth. ICAM-1 intensity increased on the luminal EC surfaces and labeled vesiculotubular profiles (VTS, defined in the present report) between days 5 and 7. After 2 weeks and at 6 months after birth, ICAM-1 labeling was weak or absent on the luminal EC surfaces. The hemangiomas presented a strong ICAM-1 reaction product on the luminal EC surfaces of small and large blood vessels associated with the VTS, with a weaker labeling of the abluminal or adventitial aspects of larger blood vessels. TEM of vesiculovacuolar structures (VVOs) within ECs from arteries and veins also demonstrated reaction product for ICAM-1 labeling. Three-dimensional stereo-pair images in the HVEM enhanced the visualization of gold particles that were attached to the inner-delimiting membrane surfaces of EC VTS, and VVOs, respectively. These observations raise the possibility that the neonatal leukocytes and tumor cells may utilize these endothelial structures as a route across the developing and injured blood-brain barrier (BBB).
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    URL: http://dx.doi.org/10.1007/s004410051214
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    Survival of rat MCH (melanin-concentrating hormone) neurons in hypothalamus slice culture: histological, pharmacological and molecular studies (1999)
    Springer
    Cell & tissue research 297 (1999), S. 23-33 
    Details
    ISSN: 1432-0878
    Keywords: Key words Melanin-concentrating hormone neurons ; Lateral hypothalamic slice culture ; Immunocytochemistry ; Ultrastructure ; In situ hybridization ; Competitive RT-PCR ; Leptin assay ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Hypothalamic slices containing the lateral hypothalamic area (LHA) were prepared from 6- to 8-day-old rats and maintained in stationary culture for up to 35 days in order to analyse how well the melanin-concentrating hormone (MCH) neurons survived. As previously reported for other brain areas, this method yielded a long-term well-preserved organotypic organization. Light- and electron-microscopic investigations showed that differentiation continued and that synaptic contacts developed in vitro. After a period of elimination of damaged cells and fibres, most of the remaining neurons and glial cells retained a normal morphology throughout the culture period. MCH neurons, in particular, survived well as attested by the strong immunocytochemical and in situ hybridization signals still observed after several weeks. In a comparison with the day of explantation, competitive reverse transcription/polymerase chain reaction demonstrated the remarkable stability of the level of MCH mRNA at least until the 20th day in culture; after 30 days, the clear decrease in this level seemed to be correlated with a loss of MCH neurons, rather than with a decrease in MCH expression. After 10 days of culture, the incubation of slices in the presence of the hormone leptin (50 ng/ml) resulted in a strong decrease of MCH gene expression, suggesting that MCH neurons retained their physiological properties. Thus, the LHA slice stationary culture, especially between one and three weeks (i.e. after tissue stabilization and before extensive cell loss), appears to be a suitable method for physiological and pharmacological studies of these neurons.
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    URL: http://dx.doi.org/10.1007/s004410051330
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    Ultrastructure and distribution dynamics of chloride cells in tilapia larvae in fresh water and sea water (1999)
    Springer
    Cell & tissue research 297 (1999), S. 119-130 
    Details
    ISSN: 1432-0878
    Keywords: Key words Chloride cells (mitochondria-rich cells) ; Teleost larvae ; Osmoregulation ; Immunohistochemistry ; Quantification ; Ultrastructure ; Oreochromis mossambicus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Integumental and branchial chloride cells of tilapia larvae (Oreochromis mossambicus) were studied at the light-microscopical and ultrastructural level. Total numbers and distribution of chloride cells were quantified after immunostaining of cross sections of the entire larvae with an antibody against the α-subunit of Na+/K+-ATPase. The majority (66%) of Na+/K+-ATPase-immunoreactive (ir) cells, i.e. chloride cells, of freshwater tilapia larvae were located extrabranchially up to 48 h after hatching. Five days after hatching, the majority (80%) of chloride cells were found in the buccal cavity. Transfer of 24-h-old larvae to 20% sea water speeded up this process; 24 h after transfer (i.e. 48 h after hatching), the majority (59%) of chloride cells were located in the buccal cavity. The branchial chloride cell population of 24-h- and 120-h-old larvae consisted of immature, mature, apoptotic and necrotic chloride cells. However, relatively more immature chloride cells were observed in freshwater larvae (42–63%) than in (previously studied) freshwater adults (21%), illustrating the developmental state of the gills. After transfer to sea water, the incidence of degenerative chloride cells did not change. Furthermore, the incidence of immature cells had decreased and a new subtype of chloride cells, the ”mitochondria-poor” cells, appeared more frequently. These mitochondria-poor chloride cells were characterised by an abundant tubular system and relatively few mitochondria, which were aligned at the border or concentrated in one part of the cytoplasm. Most of these cells did not contact the water. The function of their enhanced appearance after seawater transfer is unknown.
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    URL: http://dx.doi.org/10.1007/s004410051339
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    Structure and function of the human oocyte-cumulus-corona cell complex before and after ovulation (1999)
    Springer
    Protoplasma 206 (1999), S. 270-277 
    Details
    ISSN: 1615-6102
    Keywords: Cumulus oophorus ; Ovarian follicle ; Fertilization ; Ultrastructure ; Immunocytochemistry ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The fine structure of the human cumulus oophorus has been reviewed on the basis of scanning and transmission electron microscopic observations as well as of immunofluorescence data. Tissues sampled from preovulatory ovarian follicles and cumulus-enclosed oocytes and fertilized eggs (collected from the oviduct or obtained during in vitro fertilization procedures) have been evaluated from a microtopographic and morphodynamic point of view in order to better clarify the possible role of this population of cells. In particular, the following aspects have been studied and discussed: the presence of multiple close contacts (modulated by the interposition of the zona pellucida) between the oocyte surface and the long microvillous evaginations projecting from the inner aspect of corona cells surface (through these structures the intraovarian cumulus oophorus may control oocyte growth and metabolism up until the time of ovulation); the occurrence of different subpopulations of cells (steroid-synthetic cells, cells producing adhesive proteins, leukocytes, macrophages) in the postovulatory, extraovarian cumulus oophorus surrounding oocytes, zygotes and early developing embryos. All these elements found in the cumulus mass may positively act, through their paracrine activities, on the chemical composition of the microenvironment in which fertilization occurs.
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    URL: http://dx.doi.org/10.1007/BF01288215
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    Immunolocalization of the petunia floral binding proteins 7 and 11 during seed development in wild-type and expression mutants ofPetunia hybrida (1999)
    Springer
    Protoplasma 208 (1999), S. 224-229 
    Details
    ISSN: 1615-6102
    Keywords: Floral binding protein ; Flower development ; Immunocytochemistry ; MADS-box genes ; Ovule ; Transcription factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary DuringPetunia hybrida seed development, the MADS-box genes encoding the floral binding proteins (FBP) 7 and 11 are expressed in the seed coat and not in the endosperm or embryo. These proteins are thought to function as transcription factors and are essential for ovule formation inPetunia spp. Immunocytochemical methods were used to analyze the distribution of FBP7 and FBP11 after fertilization in wild type and ectopic and cosuppression mutants. During the first nine days of seed development the protein was found in the nuclei of seed coat cells, of both wild-type plants and plants which ectopically expressedFBP11. The signal for FBP7 and -11 proteins diminished during seed development, was first lost in the outer epidermis of the seed coat, then in the endothelium, and finally, at 9 days after pollination (DAP), the protein could not be detected anymore in the parenchyma cells of the seed coat. Although the distribution patterns in wild-type andFBP11 ectopically expressing plants are similar, the latter exhibited higher protein levels. A mild-cosuppression mutant ofFBP7 andFBP11, having only a total of 5%FBP7 and -11 mRNA, showed hardly any FBP7 and -11 proteins. The lack of FBP7 and -11 caused endosperm degeneration in the mutant at a moment when the protein had already decreased to an undetectable level in the wild type and ectopic expression mutant (i.e., at 13 DAP). It is suggested that till about 9 DAP a minimal amount of FBP7 and -11 is needed for the normal functioning of the seed coat during later stages, i.e., for transfer of nutrients to endosperm and embryo. Besides the immunocytochemical data on theFBP7 andFBP11 MADS-box gene products, the morphological analysis of wild type and mutants contributes details on early seed development inPetunia hybrida.
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    URL: http://dx.doi.org/10.1007/BF01279093
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    Interface between haustoria of parasitic members of the Scrophulariaceae and their hosts: A histochemical and immunocytochemical approach (1999)
    Springer
    Protoplasma 207 (1999), S. 84-97 
    Details
    ISSN: 1615-6102
    Keywords: Haustorium ; Immunocytochemistry ; Interface ; Parasitism ; Defense mechanisms ; Scrophulariaceae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The haustorial structure of three African parasitic members of the family Scrophulariaceae (Buchnera hispida, Rhamphicarpa fistulosa, andStriga hermonthica) has been studied with regard to the interface between haustoria and the invaded host roots. Immunocytochemical observations at the light and electron microscopical level were carried out with monoclonal antibodies against pectin. JIM5, JIM7, and hydroxyproline-rich glycoprotein (HRGP), LM1. Lignins have been visualized by phloroglucinolhydrochloric acid staining. At the margin of the lateral interface (contact area of host root cortex and parasite cells), JIM5- and JIM7-labelled substances accumulate between parasite papillae and the host root surface indicating that pectins are implicated in sealing the parasite to the attacked host organ. The lateral interface is characterized by the presence of compressed, necrotic host cells, whereas the central interface (contact area between host stele and parasite cells) is generally devoid of host cell remnants. Phenolic substances and/or lignins can be found at the site of penetration of the haustorium into the host root. These observations and the fact that HRGPs accumulate at the host side of the interface support the view of, at least, a partial defense reaction in the invaded host root tissues. Within haustoria, HRGPs were restricted to differentiating xylem elements, implying a spatio-temporal regulation of HRGPs in developmental processes.
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    URL: http://dx.doi.org/10.1007/BF01294716
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    Immunolocalization of the cell wall components inPinus densiflora pollen (1999)
    Springer
    Protoplasma 206 (1999), S. 1-10 
    Details
    ISSN: 1615-6102
    Keywords: Arabinogalactan protein ; Cell wall component ; Immunocytochemistry ; Pectin ; Pinus densiflora ; Pollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In order to compare cell wall formation in gymnosperm pollen with that in angiosperm pollen, the distribution of cell wall constituents in the pollen grain and pollen tube ofPinus densiflora was studied immunocytochemically with monoclonal antibodies JIM 5 (against non- or poorly esterified pectin), JIM 7 (against highly esterified pectin), JIM 13 (against arabinogalactan proteins, AGPs), and LM 2 (against AGPs containing glucuronic acid). In the pollen grain wall, only the outer layer of the intine was labeled with JIM 5 and weakly with JIM 7. The tube wall was scarcely labeled with JIM 5 and very weakly labeled with JIM 7. In contrast, the whole of both the intine and the tube wall was strongly labeled with JIM 13 and LM 2, and the generative-cell wall was also labeled only with LM 2. The hemicellulose B fraction, which is the main polysaccharide fraction from the pollen tube wall, reacted strongly with JIM 13 and especially LM 2, but not with antipectin antibodies. These results demonstrate that the wall constituents and their localization inP. densiflora pollen are considerably different from those reported in angiosperm pollen and suggest that the main components of the cell wall ofP. densiflora pollen are arabinogalactan and AGPs containing glucuronic acid.
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    URL: http://dx.doi.org/10.1007/BF01279247
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    Anatomical and ultrastructural changes of the floral nectary ofPisum sativum L. during flower development (1999)
    Springer
    Protoplasma 206 (1999), S. 57-72 
    Details
    ISSN: 1615-6102
    Keywords: Anatomy ; Floral nectary ; Modified stomata ; Phloem ; Pisum sativum ; Stereology ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The floral nectary ofPisum sativum L. is situated on the receptacle at the base of the gynoecium. The gland receives phloem alone which departed the vascular bundles supplying the staminal column. Throughout the nectary, only the companion cells of the phloem exhibited wall ingrowths typical of transfer cells. Modified stomata on the nectary surface served as exits for nectar, but stomatal pores developed well before the commencement of secretion. Furthermore, stomatal pores on the nectary usually closed by occlusion, not by guard-cell movements. Pore occlusion was detected most frequently in post-secretory and secretory glands, and less commonly in pre-secretory nectaries. A quantitative stereological study revealed few changes in nectary fine structure between buds, flowers secreting nectar, and post-secretory flowers. Dissolution of abundant starch grains in plastids of subepidermal secretory cells when secretion commenced suggests that starch is a precursor of nectar carbohydrate production. Throughout nectary development, mitochondria were consistently the most plentiful organelle in both epidermal and subepidermal cells, and in addition to the relative paucity of dictyosomes, endoplasmic reticulum, and their associated vesicles, the evidence suggests that floral nectar secretion inP. sativum is an energy-requiring (eccrine) process, rather that granulocrine.
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    URL: http://dx.doi.org/10.1007/BF01279253
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    Ultrastructural study of the relationship between generative and vegetative cells inMagnolia ×soulangeana Soul.-Bod. pollen grains (1999)
    Springer
    Protoplasma 206 (1999), S. 87-96 
    Details
    ISSN: 1615-6102
    Keywords: Plasmalemmic cord ; Pollen grain ; Ultrastructure ; Magnolia ×soulangeana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary InMagnolia ×soulangeana pollen grains the generative cell (GC) does not become totally free within the vegetative cell (VC), at least until the pollen tube emergence. Due to a deviation in its detachment process from the sporoderm, the opposing ends of the VC plasmalemma do not fuse themselves when the GC moves away from the intine. Consequently, the interplasmalemmic space surrounding the GC does not become isolated but rather maintains continuity with the sporoderm through a complex formation that we have called plasmalemmic cord. The real existence of this formation was confirmed through serial sectioning showing the plasmalemmic cord to consist of the VC plasmalemma. In its initial portion it is occupied by a reasonably accentuated wall ingrowth of the inner layer of the intine (intine 3). In the remainder portion, neither of the cytochemical tests used in this work have revealed the presence of a significant amount of wall material. However, ultrathin sections of samples processed either chemically or by cryofixation showed the existence of an intricate system of tubules and vesicles, some of which are evaginations of the VC plasmalemma. The hypothesis that the plasmalemmic cord may have a role in the complex interactions between the two pollen cells is discussed.
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    Distribution and transmission of endosymbiotic microorganisms in the oocytes of the pig louse,Haematopinus suis (L.) (Insecta: Phthiraptera) (1999)
    Springer
    Protoplasma 209 (1999), S. 207-213 
    Details
    ISSN: 1615-6102
    Keywords: Endosymbiont ; Mycetocyte ; Mycetome ; Oocyte ; Transovarial transmission ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary All anoplurans live symbiotically with prokaryotic microorganisms hosted in specialized cells, termed mycetocytes. In nymphs and males mycetocytes are distributed between midgut epithelial cells. In females, besides the midgut, mycetocytes are found in the reproductive organs where they are located at the base of ovarioles in contact with lateral oviducts. The mycetocyte-associated symbionts are transmitted from one generation to the next transovarially. Here, the results of histological and ultrastructural studies on the distribution and transmission of symbiotic microorganisms within the ovaries of the anopluranHaematopinus suis are presented. Interestingly, during advanced oogenesis (i.e., choriogenesis) of this species all symbionts are localized extracellularly and form a tight mass located at the posterior pole of the oocyte just below the hydropyle. In insects studied so far, such localization of transovarially transmitted microorganisms has been reported only in the closely related speciesHaematopinus eurysternus.
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    URL: http://dx.doi.org/10.1007/BF01453449
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    Effect of high-level oxygen exposure on the peroxidase activity and the neuromelanin-like pigment content of the nerve net in the earthworm, Lumbricus terrestris (1999)
    Springer
    Cell & tissue research 295 (1999), S. 349-354 
    Details
    ISSN: 1432-0878
    Keywords: Key words Neuromelanin ; Neuron ; Peroxidase ; Oxygen metabolism ; High-definition light microscopy ; Electron microscopy ; Ultrastructure ; Cytochemistry ; Substantia nigra ; Lumbricusterrestris (Annelida)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Histochemical examination of 1-μm tissue sections from the dorsal nerve plexus of the earthworm, Lumbricus terrestris, reveals multiple brown intraneuronal granules. These granules contain material morphologically and histochemically consistent with neuromelanin. When viewed with transmission electron microscopy, these were seen as single membrane-enclosed biphasic granules with diameters of 370–730 nm. Exposure of L. terrestris to high-level environmental oxygen resulted in an increase in the number of neuromelanin-like pigment granules within the neurons of the circular muscle layer. As measured by ortho-phenylenediamine hydrochloride, the endogenous peroxidase activity of extracts from worms incubated in high-level environmental oxygen was 51% more than controls. The endogenous peroxidase activity was localized in situ with 3,3-diaminobenzidine (DAB) and was found to increase in and around the neuromelanin-like pigment-containing neurons within the circular muscle layer. These studies suggest that the nerve net of L. terrestris may serve as a model to study the role of neuromelanin production in oxidative stress and its relationship to endogenous peroxidases.
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    URL: http://dx.doi.org/10.1007/s004410051241
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    Immunohistochemical evidence of the presence of aromatase P450 in the rat hypophysis (1999)
    Springer
    Cell & tissue research 295 (1999), S. 419-423 
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    ISSN: 1432-0878
    Keywords: Key words Hypophysis ; Aromatase ; Immunocytochemistry ; Morphometry ; Gender differences ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In order to analyze whether aromatase is present in the hypophysis of adult rats, we have performed an immunohistochemical study in young adult male and female rats. Our study has revealed that the hypophysis of adult rats contains aromatase, although marked differences are found between the sexes. The hypophyses of male rats have cells immunoreactive for the enzyme, 34.40% of these hypophyseal cells showing reaction. By contrast, cells from female rats show very little reaction, only 0.84% of them being reactive. No significant differences in the percentage of immunoreactive cells between one phase and another are observed during the estrous cycle. Our results point to the immunohistochemical expression of aromatase in the hypophysis of adult rats and at the same time suggest that its expression is sex-dependent. The enzyme may therefore be involved in the regulation of adenohypophyseal cytology by androgens.
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    URL: http://dx.doi.org/10.1007/s004410051248
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    The distribution and ultrastructure of class II MHC-positive cells in human dental pulp (1999)
    Springer
    Cell & tissue research 295 (1999), S. 151-158 
    Details
    ISSN: 1432-0878
    Keywords: Key words Class II MHC-positive cells ; Human leukocyte antigen-DR ; Dental pulp ; Dendritic cells ; Macrophages ; Ultrastructure ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution and ultrastructure of class II major histocompatibility complex (MHC)-positive cells were investigated in human dental pulp, employing immunohistochemistry using an anti-human leukocyte antigen (HLA)-DR-monoclonal antibody. HLA-DR-immunopositive cells, appearing spindle-like or dendritic in profile, were densely distributed throughout the dental pulp. Under the electron microscope, these cells exhibited various sizes of vesicles containing clear or opaque contents, multivesicular bodies and characteristic fine tubulovesicular structures in their cytoplasm. Some reactive cells possessed coated pits and vesicles including electron-dense materials, indicating an active endocytosis. At the periphery of the pulp tissue, the HLA-DR-immunopositive cells were predominantly situated in the subodontoblastic layer, with some located in the odontoblast layer and/or predentin and extending their cytoplasmic processes into the dentinal tubules. Cell processes of these cells occasionally made contact with several odontoblast processes in the same way as the nerve fibers in the predentin. These cells never contained the typical phagosomes frequently observed in the HLA-DR-immunoreactive macrophages in the subodontoblastic layer and the pulp core. The results suggest that the HLA-DR-immunopositive cells in the odontoblast layer and/or predentin have some regulatory function on the odontoblasts under physiological conditions, in addition to their involvement in the initial defense reaction after tooth injury.
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    URL: http://dx.doi.org/10.1007/s004410051221
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    Androgen-induced changes in Leydig cell ultrastructure and steroidogenesis in juvenile African catfish, Clarias gariepinus (1999)
    Springer
    Cell & tissue research 297 (1999), S. 291-299 
    Details
    ISSN: 1432-0878
    Keywords: Key words Teleost fish ; Puberty ; Testes ; Sex steroids ; Ultrastructure ; Steroidogenesis ; Clarias gariepinus (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The present report focuses on the mechanism(s) involved in the steroid-induced decrease of androgen production in immature African catfish testes that was observed in previous studies. Juvenile animals were implanted with Silastic pellets containing different 11-oxygenated androgens (11-ketotestosterone, KT; 11β- hydroxyandrostenedione, OHA; 11-ketoandrostenedione, KA), testosterone (T) or estradiol-17β (E2). Control groups received steroid-free pellets. Two weeks later, testis tissue fragments were either incubated with increasing concentrations of catfish luteinizing hormone (LH), or incubated with [3H]-pregnenolone ([3H]-P5) or [3H]-androstenedione ([3H]-A). Tissue fragments were also prepared for the quantitative assessment of Leydig cell morphology. Most of the parameters studied were not affected significantly by implantation of E2. Implantation of all androgens inhibited both the basal and the LH-stimulated androgen secretory capacity in vitro. This was associated with a reduced size of the Leydig cells and loss of half of their mitochondria. The studies on the metabolism of tritiated steroid hormones indicated that steroidogenic steps prior to 11β-hydroxylation, probably C17–20 lyase activity, were affected by all androgens. Although the effects of 11-oxygenated androgens and T on Leydig cells were mostly similar, previous work showed that only the 11-oxygenated androgens stimulated spermatogenesis, suggesting that distinct mechanisms of action are used by 11-oxygenated androgens and T. These mechanisms, however, seem to merge on the same target(s) to impair Leydig cell androgen production. Such a negative feedback mechanism may be of relevance in the context of the decline in androgen secretion per milligram testis tissue that accompanies the first wave of spermatogenesis in pubertal African catfish.
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    Echinococcus granulosus: praziquantel treatment against the metacestode stage (1999)
    Springer
    Parasitology research 85 (1999), S. 999-1006 
    Details
    ISSN: 1432-1955
    Keywords: Key wordsEchinococcus granulosus ; Praziquantel ; Metacestode ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The efficacy of praziquantel against the metacestode of Echinococcus granulosus was studied by means of in vitro incubations or in vivo experiments. The results of in vitro incubations indicated that the effectiveness of praziquantel was higher when the parasite material comprised cysts from cyst masses than in the case of intact cysts that retained their adventitial layer. Ultrastructural alterations in the germinal layer of collapsed cysts incubated in vitro were detected. The results obtained in mice after 4 months of treatment demonstrated no significant difference between the control and treated groups with regard to the number and wet weight of developed cysts. However, ultrastructural alterations were detected in the cyst tissue that were similar to those described in the in vitro experiment. In contrast, the effect of chemoprophylaxis on the number and the wet weight of developed cysts was extremely significant as compared with the control value, the efficacy being 99.41% and 98.32%, respectively. Moreover, ultrastructural observations of the cyst tissue revealed loss of its integrity, and no intact cyton was observed in the germinal layer of the developed cyst.
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    Morphology and ultrastructure of the anterior adhesive areas of the capsalid monogenean parasites Benedenia rohdei from the gills and B. lutjani from the pelvic fins of Lutjanus carponotatus (Pisces: Lutjanidae) (1999)
    Springer
    Parasitology research 85 (1999), S. 399-408 
    Details
    ISSN: 1432-1955
    Keywords: Key words Monogenea ; Capsalidae ; Benedenia rohdei ; B. lutjani ; Ectoparasites ; Lutjanus carponotatus ; Glands ; Ultrastructure ; Adhesion ; Attachment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The anterior adhesive areas of Benedenia rohdei from the gills and B. lutjani from the pelvic fins of Lutjanuscarponotatus at Heron Island, Australia, were studied using scanning and transmission electron microscopy. All specimens were fixed when detached from host tissue. Both monogenean species have two disc-like anteroventral attachment organs, each of which has an anterolateral adhesive area divided into three adjacent zones by tegument from the ventral surface of the attachment organ. A rod-shaped secretion and a smaller, roughly spherical secretion are associated with the anterior adhesive areas in both species; a third type of secretion occurs anteriorly but outside these adhesive areas. The electron-dense spherical secretory bodies released onto the anterior adhesive zones in these Benedenia spp. are of a single type and differ ultrastructurally from those previously reported in monogeneans living on teleost hosts. A correlation, therefore, between secretion morphology and host type is not supported. No relationship was found between parasite microhabitat and secretion morphology.
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    Electrophysiological and ultrastructural correlates of cryoinjury in sciatic nerve of the freeze-tolerant wood frog, Rana sylvatica (1999)
    Springer
    Journal of comparative physiology 169 (1999), S. 351-359 
    Details
    ISSN: 1432-136X
    Keywords: Key words Freeze tolerance ; Sciatic nerve ; Cryoinjury ; Dehydration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We investigated function and ultrastructure of sciatic nerves isolated from wood frogs (Rana sylvatica) endemic to the Northwest Territories, Canada, following freezing at −2.5 °C, −5.0 °C, or −7.5 °C. All frogs frozen at −2.5 °C, and most frogs (71%) frozen at −5.0 °C, recovered within 14 h after thawing began; however, frogs did not survive exposure to −7.5 °C. Sciatic nerves isolated from frogs frozen at −7.5 °C were refractory to electrical stimulation, whereas those obtained from frogs surviving exposure to −2.5 °C or −5.0 °C generally exhibited normal characteristics of compound action potentials. Frogs responded to freezing by mobilizing hepatic glycogen reserves to synthesize the cryoprotectant glucose, which increased 20-fold in the liver and 40-fold in the blood. Ultrastructural analyses of nerves harvested from frogs in each treatment group revealed that freezing at −2.5 °C or −5.0 °C had little or no effect on tissue and cellular organization, but that (lethal) exposure to −7.5 °C resulted in marked shrinkage of the axon, degeneration of mitochondria within the axoplasm, and extensive delamination of myelin sheaths of the surrounding Schwann cells.
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    Articular chondrocytes and synoviocytes in a co-culture system: influence on reactive oxygen species-induced cytotoxicity and lipid peroxidation (1999)
    Springer
    Cell & tissue research 296 (1999), S. 555-563 
    Details
    ISSN: 1432-0878
    Keywords: Key words Chondrocyte ; Synoviocyte ; Co-culture ; Proliferation ; Lipid peroxidation ; Cytotoxicity ; Ultrastructure ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Objective: A new co-culture system of rat articular chondrocytes and synoviocytes (HIG-82; cell line) was incubated with phorbol myristate acetate (PMA), H2O2 or a combination of Fe2+ and ascorbic acid to simulate inflammation-like radical attacks in articular joints. Methods: Chondrocytes were characterized by immunocytochemistry against collagen type II, transmission electron (TEM) and light microscopy. Lipid peroxidation was investigated by measuring thiobarbituric-acid-reactive material in the supernatants, cytotoxicity by determining release of lactate dehydrogenase and proliferation by measuring [3H]thymidine incorporation, culture protein and DNA. Results: PMA or Fe2+ and ascorbic acid induced lipid peroxidation in chondrocytes and synoviocytes that was decreased significantly in co-cultures. PMA and H2O2 dose dependently induced release of lactate dehydrogenase in chondrocytes, which was lowered in co-cultures or in previously co-cultured chondrocytes to a nearly basal level. In contrast, conditioned media of synoviocyte cultures showed no lowering effect on the radical-induced toxicity. Protection against H2O2-induced damage of cellular membranes by co-culturing was also shown by TEM. Synoviocytes released chondrocyte-stimulating growth factors spontaneously without previous interaction. Conclusion: Chondrocytes establish protective mechanisms against reactive oxygen species via an interaction with synoviocytes. Our co-culture model presents a possible way to study mechanisms of inflammation in articular joints under defined conditions.
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    Phylogenetic affiliation and ultrastructure of uncultured magnetic bacteria with unusually large magnetosomes (1998)
    Springer
    Archives of microbiology 169 (1998), S. 136-147 
    Details
    ISSN: 1432-072X
    Keywords: Key words Magnetic bacteria ; Biomineralization ; Magnetite ; 16S rRNA ; In situ hybridization ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Natural enrichments of magnetic bacteria from the Itaipu lagoon near Rio de Janeiro were dominated by coccoid-to-ovoid morphotypes that produced unusually large magnetosomes. To determine the phylogenetic position of these unusual microorganisms, 16S rRNA genes were retrieved from bacteria magnetically separated from sediment of the Itaipu lagoon by in vitro amplification and cloning of PCR products into a plasmid vector. Partial sequencing of the obtained clones revealed two clusters of closely related sequences affiliated to a distinct lineage consisting exclusively of magnetic bacteria within the α-subclass of Proteobacteria. For a detailed phylogenetic analysis, several almost complete sequences of the 16S rRNA genes were determined. One representative clone of each cluster provided a PCR template for the in vitro transcription of group-specific polynucleotide probes complementary to a variable region of the 16S rRNA molecule. At least three different morphotypes of magnetic bacteria were reliably identified by post-embedding hybridization of ultra-thin sections. Electron microscopic analyses of hybridized cells enabled for the first time a detailed description of the morphological variety and ultrastructure of phylogenetically identified, uncultured magnetic bacteria. Two distinct coccoid bacteria were identified by the transcript probe complementary to the 16S rRNA sequence mabrj12, whereas the probe complementary to the sequence mabrj58 allowed the identification of an ovoid morphotype that displayed magnetosomes with the largest volumes observed to date.
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    Subcellular localization of β-1,3-glucanase in Puccinia recondita f.sp. tritici-infected wheat leaves (1998)
    Springer
    Planta 204 (1998), S. 324-334 
    Details
    ISSN: 1432-2048
    Keywords: Key words:β-1 ; 3-Glucanase ; Immunocytochemistry ; Leaf rust pathogen ; Resistance ; Triticum (pathogen resistance)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. An antiserum raised against the purified 33-kDa β-1,3-glucanase of wheat (Triticum aestivum L.) was employed to investigate the ultrastructural localization of the enzyme in wheat leaves infected with Puccinia recondita Rob. ex Desm. f.sp. tritici Eriks. and Henn. using a post-embedding immunogold labelling technique. In both compatible and incompatible interactions, β-1,3-glucanase was detected in the host plasmalemma and in the domain of the host cell wall near the plasmalemma of the mesophyll cells, but higher concentrations of the enzyme were detected in infected resistant wheat leaves than in infected susceptible ones. β-1,3-Glucanase was also found in the secondary thickening of xylem vessels and in the walls of guard cells, epidermal cells and phloem elements, while no labelling was observed in host organelles, viz. vacuoles, mitochondria, endoplasmic reticulum, Golgi bodies, nuclei and chloroplasts. A low concentration of the enzyme was detected on the intercellular hyphal wall and in the hyphal cytoplasm. In the compatible interaction, β-1,3-glucanase was demonstrated to accumulate predominantly in the haustorial wall and extrahaustorial matrix. In the incompatible interaction, strong labelling for β-1,3-glucanase was found in host cell wall appositions, in the extracellular matrix in the intercellular space, and in electron-dense structures of host origin which occurred in the incompatible interaction only.
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    Differences in the initiation of the zygotic and parthenogenetic pathway in the Salmon lines of wheat: ultrastructural studies (1998)
    Springer
    Sexual plant reproduction 11 (1998), S. 121-130 
    Details
    ISSN: 1432-2145
    Keywords: Key words Egg cell ; Parthenogenesis ; Synergid ; Ultrastructure ; Wheat ; Zygote
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The ultrastructure of the egg apparatus of the sexual (aestivum)-Salmon line (aS) and the isogenic but alloplasmic (kotschyi)-Salmon line (kS) of the Salmon system of wheat was studied by transmission electron microscopy 3 days before and during anthesis. Additionally, the zygotic stage of aS, 17 h after pollination, was included. Metabolic activity of egg cells from the sexual line aS was low 3 days before anthesis and increased dramatically after pollination and fertilization. This timing of increased activity was evident because of changes occurring in the egg cell nucleus and nucleolus, polysomes, endoplasmic reticulum and Golgi apparatus, and the completion of the cell wall around the zygote. In contrast to the sexual line, the egg cell of the parthenogenetic line showed high activity 3 days before anthesis. The metabolic and ultrastructural characters observed in the nucleus and cytoplasm of the kS line 3 days before and during anthesis corresponded with those of the isogenic sexual line aS during anthesis and 17 h after pollination, respectively. High metabolic activity observed in the persistent synergid of kS may be connected with the occurrence of additional embryos in seeds (twins) of this line.
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    Ultrastructural and molecular study of plastid inheritance in Abies alba and some Abies hybrids (1998)
    Springer
    Sexual plant reproduction 11 (1998), S. 284-291 
    Details
    ISSN: 1432-2145
    Keywords: Key words Abies ; Egg cell ; Plastid inheritance ; RFLP ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  The ultrastructure of egg cells in Abies alba was examined to elucidate the lack of maternal inheritance of plastids. Before fertilization, maternal plastids are absent in the perinuclar zone containing mainly mitochondria and smooth endoplasmic reticulum. During egg cell development the maternal plastids are transformed into large inclusions which are situated mostly towards the periphery of the egg cell, and finally disintegrate. As a consequence, they do not participate in zygote formation. RFLP analysis of cpDNA of parental trees and their F1 interspecific hybrids (A. alba×A. numidica, A. alba×A. nordmanniana, A. nordmanniana×A. Alba) using HindIII and BamHI showed a paternal mode of cpDNA inheritance. Paternal inheritance has also been found with PCR/RFLP analysis of cpDNA from parental trees and their hybrids (A. alba×A. pinsapo, A. pinsapo×A. alba, A. pinsapo×A. numidica) using ApaI and HaeIII digests, as well as in the crosses of A. cephalonica×A. nordmanniana, A. nordmanniana×A. cephalonica, A. cephalonica×A. numidica using TagI digests.
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    Ultrastructural, morphometrical and immunocytochemical analyses of the exocrine pancreas in a hibernating dormouse (1998)
    Springer
    Cell & tissue research 292 (1998), S. 531-541 
    Details
    ISSN: 1432-0878
    Keywords: Key words Pancreas ; exocrine ; Hibernation ; Amylase ; Immunocytochemistry ; Muscardinus avellanarius (Rodentia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Pancreatic acinar cells of euthermic, hibernating and arousing individuals of the hazel dormouse Muscardinus avellanarius (Gliridae) have been observed at the electron-microscopic level and analysed by means of ultrastructural morphometry and immunocytochemistry in order to investigate possible fine structural changes of cellular components during periods of strikingly different degrees of metabolic activity. During hibernation, the cisternae of the rough endoplasmic reticulum (RER) flatten assuming a parallel pattern, the Golgi apparatus is extremely reduced and the mitochondria contain many electron-dense particles. The cell nuclei appear irregularly shaped, with deep indentations containing small zymogen granules. They also contain abundant coiled bodies and unusual constituents, such as amorphous bodies and dense granular bodies. Large numbers of zymogen granules occur in all animals. However, the acinar lumina are open and filled with zymogen only in euthermic animals, whereas, in hibernating and arousing individuals, they appear to be closed. Morphometrical analyses indicate that, in pancreatic acinar cells, nuclei and zymogen granules significantly decrease in size from euthermia to hibernation, probably reflecting a drastic decrease of metabolic activities, mainly protein synthesis and processing. In all the studied animals, immunocytochemistry with specific antibodies has revealed an increasing gradient in α-amylase content along the RER-Golgi-zymogen granule pathway, reflecting the protein concentration along the secretory pathway. Moreover, during deep hibernation, significantly larger amounts of α-amylase accumulate in RER and zymogen granules in comparison to the other seasonal phases analysed. Upon arousal, all cytoplasmic and nuclear constituents restore their euthermic aspect and all morphometrical and immunocytochemical parameters exhibit the euthermic values, thereby indicating a rapid resumption of metabolic activities.
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    Expression pattern for adrenomedullin during pancreatic development in the rat reveals a common precursor with other endocrine cell types (1998)
    Springer
    Cell & tissue research 293 (1998), S. 95-100 
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    ISSN: 1432-0878
    Keywords: Key words Adrenomedullin ; Pancreas ; Development ; Immunocytochemistry ; Colocalizations ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Adrenomedullin is an α-amidated 52-amino acid peptide involved in many physiological actions, among others the regulation of insulin secretion. Using immunohistochemical methods, we found that adrenomedullin immunoreactivity first appears at day 11.5 of embryonic development in the rat, coinciding with the appearance of pancreatic glucagon. The early appearance of adrenomedullin in the developing pancreas may indicate an active involvement in either the morphogenesis of the organ or its endocrine/paracrine/autocrine hormone regulation during intrauterine life. We also investigated the pattern of colocalizations of adrenomedullin with the other pancreatic hormones. At some point during development all the cell types express adrenomedullin, progressively evolving towards the adult pattern where only the pancreatic polypeptide cells contain a strong immunoreactivity for adrenomedullin. At this point the remaining cells of the islet are, in general, weakly stained. This sequential and time-dependent expression of adrenomedullin suggests a tight regulation similar to that observed for other modulatory substances responsible for embryonic morphogenesis.
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    Immunocytochemistry and in situ hybridization studies of pepsinogen C-producing cells in developing rat fundic glands (1998)
    Springer
    Cell & tissue research 293 (1998), S. 121-131 
    Details
    ISSN: 1432-0878
    Keywords: Key words Pepsinogen C ; Ontogeny ; Mucous neck cell ; Chief cell ; Intermediate mucopeptic cell ; Immunocytochemistry ; In situ hybridization ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The ontogeny of pepsinogen C-producing cells in rat fundic glands was studied by means of light and electron microscopy using an antiserum raised against a synthetic peptide based on rat pepsinogen C. To confirm the immunocytochemistry results, the expression of rat pepsinogen C messenger RNA (mRNA) in the fundic gland was also examined by in situ hybridization using a digoxigenin-labeled RNA probe. In adult rats, pepsinogen C was produced by chief cells, mucous neck cells, and intermediate mucopeptic cells. Pepsinogen C-producing cells appeared in embryos as early as 18.5 days’ gestation. The development of these cells could be classified into four stages: (1) 18.5 days’ gestation to 0.5 days after birth; (2) 0.5 days to 2 weeks after birth; (3) 3–4 weeks after birth; (4) 4–8 weeks after birth. In embryos and young animals, pepsinogen C-producing cells were mucopeptic cells. By 4 weeks after birth, mucous neck cells could be distinguished morphologically. The maturation stages of the chief cells could be traced by electron microscopy along the longitudinal axis of the rat fundic gland by double-staining with anti-pepsinogen C antibody and periodic acid-thiocarbohydrazide-silver proteinate. Positive reactions for pepsinogen C and pepsinogen C mRNA expression were detected in mucous neck cells. Therefore, we conclude that mucous neck cells are precursor cells of chief cells. Mucous neck cells, intermediate cells, and chief cells are in the same differentiating cell lineage.
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    Segmental muscle fiber lesions after repetitive eccentric contractions (1998)
    Springer
    Cell & tissue research 293 (1998), S. 165-171 
    Details
    ISSN: 1432-0878
    Keywords: Key words Muscle injury ; Cytoskeleton ; Sarcomere organisation ; Immunohistochemistry ; Ultrastructure ; Rabbit (New Zealand White)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Immunohistochemical and electron-microscopic techniques were used to analyze the extensor digitorum longus muscles of New Zealand White rabbits 1 h, 1 day, 3, 7, and 28 days after repetitive eccentric contractions. Loss of the cytoskeletal protein desmin was the earliest manifestation of injury. Apart from 1 h post-exercise, all desmin-negative fibers stained positively with antibody to plasma fibronectin, indicating loss of cellular integrity accompanying cytoskeletal disruption. Fiber sizes were significantly increased from 1–7 days after exercise. The large (hyaline) fibers found in histological sections after repetitive eccentric contractions resulted from segmental hypercontraction of the fiber. This phenomenon occurred proximally and distally to plasma membrane lesions of the muscle fiber and necrosis and manifested itself as very short sarcomere lengths. Thus, in serial sections, staining characteristics, sizes and shapes of one and the same fiber often varied dramatically. We conclude that the following sequence of events occurs: cytoskeletal disruptions, loss of myofibrillar registry, i.e., Z-disk streaming and A-band disorganization, and loss of cell integrity as manifested by intracellular plasma fibronectin stain, hypercontracted regions, and invasion of cells. When a fiber is disrupted, the remaining intact fibers apparently take up the tension put on the muscle and later fewer fibers are subjected to eccentric contractions.
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    Quantitative analysis of inputs to somatostatin-immunoreactive descending interneurons in the myenteric plexus of the guinea-pig small intestine (1998)
    Springer
    Cell & tissue research 294 (1998), S. 219-226 
    Details
    ISSN: 1432-0878
    Keywords: Key words Enteric nervous system ; Somatostatin ; Immunocytochemistry ; Intestinal motility ; Synaptic connections ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Somatostatin immunoreactivity occurs in a specific subgroup of cholinergic descending interneurons in the myenteric plexus of the guinea-pig small intestine. In the present work, we made light- and electron-microscopic investigations of chemically defined inputs to these neurons, in order that the origins of the connections of other neurons with them could be deduced. Somatostatin-immunoreactive synapses and close contacts were found on the cell bodies and filamentous processes of somatostatin neurons; these were 84% of all inputs. It is thus confirmed that this class of interneuron forms chains that project anally. Descending interneurons with immunoreactivity for nitric oxide synthase provided 14% of inputs to somatostatin-immunoreactive descending interneurons. An antiserum against a calcium-binding protein, calbindin, was used as marker for the majority of intrinsic primary afferent neurons, AH/Dogiel type II neurons; this class of neurons provided only 2.5% of the inputs to somatostatin-immunoreactive descending interneurons. We conclude that somatostatin-immunoreactive descending interneurons are involved in the conduction of impulses distally along the full length of the small intestine, but receive only a minor input from calbindin-immunoreactive primary afferent neurons.
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    Electron-immunocytochemical localization of P2X1 receptors in the rat cerebellum (1998)
    Springer
    Cell & tissue research 294 (1998), S. 253-260 
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    ISSN: 1432-0878
    Keywords: Key words P2X1 receptor ; Ultrastructure ; Cerebellum ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The distribution of the P2X1 subtype of purinoceptors associated with the extracellular activities of ATP was studied in the rat cerebellum at the electron-microscope level. Receptors were labelled with peroxidase-antiperoxidase and the avidin-biotin-peroxidase complex for immunocytochemistry. Immunoreactivity to P2X1 receptors was localized in subpopulations of synapses between varicosities of parallel fibres of granule cells and dendritic spines of Purkinje cells. Unlabelled varicosities of parallel fibres formed asymmetric synapses with labelled dendritic spines, whereas labelled varicosities of parallel fibres formed asymmetric synapses with unlabelled dendritic spines. P2X1 immunoreactivity was also localized in some astrocyte processes. The functional significance of these findings is discussed.
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    Immunocytochemical localization of annexin 5, a calcium-dependent phospholipid-binding protein, in rat endocrine organs (1998)
    Springer
    Cell & tissue research 292 (1998), S. 85-89 
    Details
    ISSN: 1432-0878
    Keywords: Key words Annexin 5 ; Immunocytochemistry ; Pituitary ; Ovary ; Testis ; Adrenal gland ; Thyroid gland ; Rat (wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Annexin 5, a unique calcium- and phospholipid-binding protein, has been investigated for its specific distribution in rat endocrine organs by immunocytochemistry with a specific antiserum to recombinant rat annexin 5. Follicular epithelial cells and parafollicular cells of the thyroid gland, adrenocortical cells of the zona fasciculata and zona reticularis, luteal cells, testicular interstitial cells, and Sertoli cells were shown to contain annexin 5. To examine whether the synthesis of annexin 5 would be affected by a change in humoral signal, the distribution of annexin 5 in the anterior pituitary was examined three weeks after ovariectomy. The withdrawal of ovarian hormones induced huge castration cells in the anterior pituitary gland, which contained abundant annexin 5. Annexin 5 was not detected in the pineal gland, the parathyroid gland, the islet of Langerhans, the adrenal medulla, zona glomerulosa cells, and granulosa cells. Since annexin 5 was shown to exist in many of the endocrine tissues examined, to be localized in specific cell types, and to be abundant in castration cells, it is suggested that annexin 5 contributes to secretory cell functions, which may be common to endocrine cells secreting chemically different hormones.
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    Chymotrypsin gene expression in rat peripheral organs (1998)
    Springer
    Cell & tissue research 292 (1998), S. 345-354 
    Details
    ISSN: 1432-0878
    Keywords: Key words Pancreas ; Stomach ; Duodenum ; Ribonuclease protection assay ; Immunocytochemistry ; Protease ; Rat ; (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Prior studies have revealed the presence of chymotrypsinlike protease in peripheral organs, although no definitive evidence for the synthesis of this enzyme in tissue other than the pancreas is available. In an attempt to detect chymotrypsinogen mRNA in peripheral organs, a fragment of the pancreatic chymotrypsin mRNA from rat was amplified using PCR. The sequence was identified as a portion of the rat chymotrypsin B gene overlapping exon 5 through exon 7. It was subcloned into the pGEM-4Z vector and used as a template for the vitro transcription of an antisense riboprobe. Using ribonuclease protection and Northern blot analyses, chymotrypsin mRNA was detected in the rat pancreas, stomach, duodenum, ovary, and spleen. Monoclonal and polyclonal antisera against chymotrypsin detected chymotrypsinlike immunoreactivity in rat and human pancreas, rat stomach, duodenum and jejunum. Electrophoresis and immunoblotting revealed chymotrypsin-chymotrypsinogen bands (25–29 kDa) in the stomach and duodenum. Synthesis of a potent protease such as chymotrypsin in tissue other than pancreas is significant, suggesting a potential physiological and/or pathological role in these tissues.
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    URL: http://dx.doi.org/10.1007/s004410051065
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    Cutaneous glands of male and female impalas (Aepyceros melampus): seasonal activity changes and secretory mechanisms (1998)
    Springer
    Cell & tissue research 292 (1998), S. 377-394 
    Details
    ISSN: 1432-0878
    Keywords: Key words Cutaneous scent glands ; Apocrine glands ; Myoepithelial cells ; Holocrine glands ; Ultrastructure ; Lectins ; Cytokeratins ; Impala ; Aepyceros melampus (Artiodactyla)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The cutaneous glands of the forehead and the metatarsus were studied by histological and histochemical methods and electron microscopy in adult male and female impalas in various seasons of the year. All glandular areas consist of apocrine and holocrine glands, which, however, occur in different proportions. Our findings in the apocrine gland cells suggest (1) the synthesis and exocytosis of a glycoproteinaceous secretory product stored in secretory granules, (2) typical apocrine secretion of the transformed apical cytoplasm, and (3) transepithelial fluid transport. The Golgi apparatus and apical membrane have binding sites for several lectins (PNA, HPA, RCA I, WGA). Cytokeratins 7, 14 and 19 are expressed at various intracellular localizations, suggesting an active role in the secretory mechanisms. The glands of the male forehead show marked seasonal changes in activity that are correlated with the main phases of the reproductive cycle, with the highest cellular activity occurring during the rut in April/May. The female forehead glands are only moderately developed and do not undergo seasonal changes. The metatarsal glands are of equal size in males and females and show no seasonal changes in activity. This study supports the hypothesis that (1) forehead glands in the male have a signaling role in the rut and (2) the metatarsal glands have a more general, probably social role maintaining and restoring contact between herd members.
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    URL: http://dx.doi.org/10.1007/s004410051068
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    Immunocytochemical alterations in the intra-acrosomal antigen MN7 during epididymal maturation of guinea pig spermatozoa (1998)
    Springer
    Cell & tissue research 292 (1998), S. 427-433 
    Details
    ISSN: 1432-0878
    Keywords: Key words Acrosome ; Epididymal maturation ; Monoclonal antibody ; Immunocytochemistry ; Spermatozoa ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  We have previously shown that a 90-kDa intra-acrosomal antigen, MN7, is restricted to the anterior acrosomal region of mouse, rat, and hamster spermatozoa. The present study has examined the localization and the behavior of MN7 during sperm maturation in the epididymis of the guinea pig by immunoelectron microscopy. MN7 showed not only a specific localization in the apical segment of the guinea pig sperm acrosome, but also a distinct alteration during maturation, as follows. MN7 was exclusively found both at the dorsal matrix and on the outer acrosome membrane (OAM)/matrix-associated materials in the apical segment. MN7 was initially distributed throughout the electron-lucent dorsal matrix in immature sperm but, during maturation, became more restricted to the spherical bodies within the electron-lucent area. MN7 on OAM/matrix-associated materials was first distributed along the ventral margin and the small area posterior to the dorsal matrix but, during maturation, disappeared from the ventral margin and became restricted to the dorsal region. These results indicate that MN7 is a good tool for studying the stepwise maturation of epididymal spermatozoa.
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    Munc-18–1 and cysteine string protein (csp) in pinealocytes of the gerbil pineal gland (1998)
    Springer
    Cell & tissue research 293 (1998), S. 245-252 
    Details
    ISSN: 1432-0878
    Keywords: Key words Synaptic-like microvesicles ; Synaptophysin ; Synaptobrevin ; Immunocytochemistry ; Immunoelectron microscopy ; Meriones unguiculatus (Rodentia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Mammalian pinealocytes contain several synaptic membrane proteins which probably play a role in the targeting and exocytosis of secretory vesicles, in particular of synaptic-like microvesicles (SLMVs). The latter are considered as the endocrine equivalent of neuronal synaptic vesicles. By means of immunocytochemical techniques and immunoblot analyses, we now show that two further key components of the molecular apparatus regulating neurotransmitter release are present in the gerbil pineal gland, i.e., munc-18–1 and cysteine string protein (csp). In addition to varicosities of nerve fibres, munc-18–1 and csp could be localized to pinealocytes where both proteins were markedly enriched in process swellings. When using antibodies against csp for an immunogold electron-microscopic study of pinealocytes, gold particles consistently decorated profiles of pleomorphic SLMVs. Interestingly, we found that also the cytosolic protein munc-18, which is partially recruited to the plasmalemma in neurons, was associated to a significant extent with SLMVs of pinealocytes and synaptic vesicles of neurons, respectively. This localization implies that munc-18 at least partially exerts its regulatory functions while being bound to secretory vesicle membranes. Our results indicate that in endocrine cells such as pinealocytes the synaptic proteins munc-18–1 and csp play essential roles during the life cycle of SLMVs.
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    Pleated septate junctions in leech photoreceptors: ultrastructure, arrangement of septa, gate and fence functions (1998)
    Springer
    Cell & tissue research 293 (1998), S. 253-269 
    Details
    ISSN: 1432-0878
    Keywords: Key words Septate junctions ; Ultrastructure ; Permeability ; Ions ; Epithelium ; Photoreceptor ; Hirudo medicinalis (Hirudinea)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The leech photoreceptor forms a unicellular epithelium: every cell surrounds an extracellular “vacuole” that is connected to the remaining extracellular space via narrow clefts containing pleated septate junctions. We analyzed the complete structural layout of all septa within the junctional complex in elastic brightfield stereo electron micrographs of semithin serial sections from photoreceptors infiltrated with colloidal lanthanum. The septa form tortuous interseptal corridors that are spatially continuous, and open ended basally and apically. Individual septa seem to be impermeable to lanthanum; interseptal corridors form the only diffusional pathway for this ion. The junctions form no diffusion barrier for the electron-dense tracer Ba2+, but they hinder the diffusion of various hydrophilic fluorescent dyes as demonstrated by confocal laser scanning microscopy (CLSM) of live cells. Even those dyes that penetrate gap junctions do not diffuse beyond the septate junctions. The aqueous diffusion pathway within the septal corridors is, therefore, less permeable than the gap-junctional pore. Our morphological results combined with published electrophysiological data suggest that the septa themselves are not completely tight for small physiologically relevant ions. We also examined, by CLSM, whether the septate junctions create a permeability barrier for the lateral diffusion of fluorescent lipophilic dyes incorporated into the peripheral membrane domain. AFC16, claimed to remain in the outer membrane leaflet, does not diffuse beyond the junctional region, whereas DiIC16, claimed to flip-flop, does. Thus, pleated septate junctions, like vertebrate tight junctions, contribute to the maintenance of cell polarity.
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    Internal division of capillaries in rat skeletal muscle in response to chronic vasodilator treatment with α1-antagonist prazosin (1998)
    Springer
    Cell & tissue research 293 (1998), S. 293-303 
    Details
    ISSN: 1432-0878
    Keywords: Key words Angiogenesis ; Capillary growth ; Prazosin ; Shear stress ; Skeletal muscle ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Chronic vasodilatation represents a stimulus for capillary growth associated with increased luminal shear stress. We have examined the ultrastructure of more than 2000 capillaries to establish whether the sequence of angiogenesis in response to this stimulus is similar to that described during development and under pathological circumstances. Administration of the α1-blocker prazosin to rats for 2 weeks led to a greater capillary length density in extensor hallucis proprius muscles without any change in capillary tortuosity: J v(c,f)=262±54 compared with 350±17 mm–2, control compared with prazosin (P〈0.002). There were obvious signs of endothelial cell (EC) activation after prazosin treatment, including an increased proportion of capillaries with rough endoplasmic reticulum, large cytoplasmic vacuoles, thickened endothelium and an irregular luminal surface. Capillaries from control muscles had a maximum of three ECs in cross section, whereas four ECs were noted in 0.8+0.5% of capillaries after 1 week (n.s.) and 2.5±0.9% after 2 weeks (P〈0.01) of treatment. This could be due to elongation and/or migration of ECs, as cell proliferation has not been described at these time points. There was also an increase in the proportion of capillaries having a narrow, slit-like lumen (1.7±0.8% of controls; 7.1±1.9% at 1 week; 8.8±2.5% at 2 weeks; P〈0.02), some of which were smaller in size (less than 2 μm diameter) than in controls (3–5 μm) and/or “seamless”, i.e. lacking EC junctions. These may represent newly formed vessels. Focal discontinuity of the basement membrane and abluminal EC processes were rarely seen, and capillary growth by abluminal sprouting appeared to be very infrequent (less than 0.001% of profiles). Of more importance was growth starting from the luminal side. Significantly more thin cytoplasmic processes were observed protruding into the lumen of capillaries after 1 week (47.5±6.2%, P〈0.001) and 2 weeks of prazosin (34.2±5.5%, P〈0.05) than in control vessels (16.7±3.9%). Some of these traversed the entire lumen and connected with endothelium of the opposite side, probably involving membrane fusion, resulting in the appearance of a double lumen. Individual capillaries with a complete double lumen were observed after 2 weeks’ prazosin but comparatively rarely, in only four out of six muscles. These findings indicate a pattern of luminal growth which is completely different from intussusceptive growth previously described during development, and from the abluminal capillary sprouting seen under pathological circumstances.
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    Immunocytochemical and immunochemical study of enamelins, using antibodies against porcine 89-kDa enamelin and its N-terminal synthetic peptide, in porcine tooth germs (1998)
    Springer
    Cell & tissue research 293 (1998), S. 313-325 
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    ISSN: 1432-0878
    Keywords: Key words Enamelin ; Immunocytochemistry ; Amelogenesis ; Tooth development ; Enamel ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Enamelins comprise an important family of the enamel matrix proteins. Porcine tooth germs were investigated immunochemically and immunocytochemically using two antibodies: a polyclonal antibody raised against the porcine 89-kDa enamelin (89 E) and an affinity purified anti-peptide antibody against the porcine enamelin amino-terminus (EN). Immunochemical analysis of layers of immature enamel from the matrix formation stage detected immunopositive protein bands ranging from 10 kDa to 155 kDa in the outer layer enamel sample irrespective of the antibodies used. In contrast, the middle and inner enamel layer mainly contained lower molecular weight enamelins. In immunocytochemical analyses of the differentiation stage, 89 E stained enamel matrix islands around mineralized collagen fibrils of dentin, while EN stained both enamel matrix islands and stippled material. At the matrix formation stage, both antibodies intensely stained enamel prisms located in the outer layer. In the inner layer, 89 E moderately stained enamel matrix homogeneously, while EN primarily stained the prism sheath. The intense immunoreaction over the surface layer of enamel matrix at the matrix formation stage, following staining with 89 E and EN, disappeared by the end of the transition stage and the early maturation stage, respectively. The Golgi apparatus and secretory granules in the ameloblasts from the late differentiation stage to the transition stage were immunostained by both antibodies. These results suggest that expression of enamelin continues from late differentiation to the transition stage and the cleavage of N-terminal region of enamelin occurs soon after secretion. Some enamelin degradation products, which apparently have no affinity for hydroxyapatite crystals, concentrate in the prism sheaths during enamel maturation.
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    Ontogenic development of salmon GnRH and chicken GnRH-II systems in the brain of masu salmon (Oncorhynchus masou) (1998)
    Springer
    Cell & tissue research 293 (1998), S. 427-434 
    Details
    ISSN: 1432-0878
    Keywords: Key words Salmon GnRH ; Chicken GnRH ; II ; Radioimmunoassay ; Immunocytochemistry ; In situ hybridization ; Oncorhynchus masou (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Ontogenic development of salmon gonadotropin-releasing hormone (GnRH) and chicken GnRH-II systems in masu salmon (Oncorhynchus masou) was examined. Salmon GnRH was first detected by radioimmunoassay in the embryo on day 36 after fertilization. Salmon GnRH-immunoreactive fibers were detected initially by immunocytochemistry in the vicinity of the olfactory placode of the embryo (day 36) and were distributed widely in the brain as well as in the pituitary gland of fish just after hatching (day 80). Salmon GnRH-immunoreactive neuronal somata were first detected about 6 months after fertilization in the rostroventral brain area, ranging from the olfactory nerve to the preoptic area. Salmon GnRH neuronal somata were detected earlier by in situ hybridization than by immunocytochemistry. Neuronal somata expressing salmon GnRH mRNA were first detected in the vicinity of the olfactory epithelium on day 40 and then were seen to be migrating from the olfactory epithelium, along the olfactory nerve, on day 60 and in the transitional area between olfactory nerve and olfactory bulb on day 80. In the brain, these neurons were first detected in the ventral olfactory bulb on day 80, and thereafter they were also detected in the caudal brain regions. The chicken GnRH-II system was detected later than the salmon GnRH system; chicken GnRH-II was first detected by radioimmunoassay on day 57, and chicken GnRH-II-immunoreactive fibers were first detected on day 67. Chicken GnRH-II-immunoreactive neuronal somata were not detected during the observation period. These results suggest that salmon GnRH neurons derive from the olfactory placode and then migrate into the brain and that salmon GnRH is synthesized before chicken GnRH-II.
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    Subcellular effects and localization of binding sites of phytohemagglutinin in the potato leafhopper, Empoasca fabae (Insecta: Homoptera: Cicadellidae) (1998)
    Springer
    Cell & tissue research 294 (1998), S. 561-571 
    Details
    ISSN: 1432-0878
    Keywords: Key words Plant lectins ; Epithelial cells ; Immunocytochemistry ; Autoradiography ; Immunoelectron microscopy ; Potato leafhopper ; Empoasca fabae (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract To identify the means by which phytohemagglutinin (PHA) exerts its toxicity on the potato leafhopper, four different methods (thick and semi-thin sectioning combined with immunofluorescent staining, in vitro receptor autoradiography, and immunoelectron microscopy) were used to elucidate the PHA target tissue, binding site, and its effects on this tissue. Sixteen 1- or 2-day-old female potato leafhoppers were fed for 36 h on each of three treatments: a control, diet or a diet containing either the PHA-E subunit or the PHA-L subunit. The PHA-E subunit, but not PHA-L, had previously been shown to be lethal. The insects were then prepared for both light and confocal microscopy. Analysis of images showed that PHA bound only to the surface of midgut epithelial cells of the potato leafhopper. PHA-E caused severe disruption, disorganization, and elongation of the brush border microvilli, and swelling of the epithelial cells into the lumen of the gut, leading to complete closure of the lumen. Furthermore, PHA-E stimulated the division of midgut epithelial cell nuclei, leading to two nuclei in each cell. Nuclei later elongated and degraded. In contrast, PHA-L had little effect on the epithelial cells of the midgut. It did not strongly bind to the surface of epithelial cells and caused much less disruption of brush-border microvilli, less disorganization of the cells and less elongation of nuclei. Strong binding of PHA occurred solely on the cell membrane of the brush border microvilli of epithelial cells. In contrast, the controls (i.e., midgut tissue, blocking agent, PHA, and antibodies) showed that midgut tissue was not autofluorescent and showed no fluorescent binding signal. Analysis of both bright- and dark-field images obtained by autoradiography and immunoelectron microscopy confirmed these findings.
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    Monoclonal antibodies SMI 311 and SMI 312 as tools to investigate the maturation of nerve cells and axonal patterns in human fetal brain (1998)
    Springer
    Cell & tissue research 291 (1998), S. 433-443 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Neurofilaments ; Phosphorylation ; Differentiation ; Immunocytochemistry ; Brain storage ; Fixation ; Microwave ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Neurofilaments, which are exclusively found in nerve cells, are one of the earliest recognizable features of the maturing nervous system. The differential distribution of neurofilament proteins in varying degrees of phosphorylation within a neuron provides the possibility of selectively demonstrating either somata and dendrites or axons. Non-phosphorylated neurofilaments typical of somata and dendrites can be visualized with the aid of monoclonal antibody SMI 311, whereas antibody SMI 312 is directed against highly phosphorylated axonal epitopes of neurofilaments. The maturation of neuronal types, the development of area-specific axonal networks, and the gradients of maturation can thus be demonstrated. Optimal immunostaining with SMI 311 and SMI 312 is achieved when specimens are fixed in a mixture of paraformaldehyde and picric acid for up to 3 days and sections are incubated free-floating. Neurons, with their dendritic domains immunostained by SMI 311 in a Golgi-like manner, can be completely visualized in relatively thick sections. The limitations of Golgi-preparations, such as glia-labeling, artifacts, and the staining of only a small non-representative percentage of existing neurons, are not apparent in SMI preparations, which additionally provide the possibility of selectively staining axonal networks. The results achieved in normal fetal brain provide the basis for studies of developmental disturbances.
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    Two differing salmon GnRH precursor mRNAs are co-expressed in the brain of sockeye salmon (Oncorhynchus nerka) (1998)
    Springer
    Cell & tissue research 292 (1998), S. 267-273 
    Details
    ISSN: 1432-0878
    Keywords: Key words Co-expression of mRNAs ; Gonadotropin-releasing hormone ; Immunocytochemistry ; In situ hybridization ; Oncorhynchus nerka (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The localization of two salmon-type gonadotropin-releasing hormone (sGnRH) precursors, pro-sGnRH-I (short type) and pro-sGnRH-II (long type), was investigated by using in situ hybridization techniques in the brain of the landlocked sockeye salmon, Oncorhynchus nerka. We used 30-mer oligonucleotide probes complementary to pro-sGnRH-I and pro-sGnRH-II cDNA. No significant differences were observed in the localization of sGnRH neurons expressing pro-sGnRH-I and pro-sGnRH-II mRNAs; both were expressed in the olfactory nerve, the olfactory bulbs, the regions between the olfactory bulb and telencephalon, the ventral telencephalon, the preoptic area, and the hypothalamus. Almost all sGnRH neurons examined co-expressed both precursors. The expression of two sGnRH precursors in the same neuron and the wide distribution of such neurons in the brain suggest that there are no functional differences between the two precursors.
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    Visualization of interstitial cells of Cajal in the mouse colon by vital staining (1998)
    Springer
    Cell & tissue research 292 (1998), S. 275-282 
    Details
    ISSN: 1432-0878
    Keywords: Key words Interstitial cells (Cajal) ; Large intestine ; Fluorescent dyes ; Vital staining ; Ultrastructure ; Mouse (BALB/c)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Interstitial cells of Cajal (ICCs) are believed to be a major element in generating the spontaneous rhythm of the gastrointestinal tract. A prominent problem in the study of these cells has been the difficulty in observing them in intact tissues. We used the lipophilic dye DiI to stain ICCs in the submucosal-circular muscle border of freshly dissected mouse colon. The placement of small DiI crystals in this area resulted in the labeling of ICC-like cells. Two main morphological cell types, viz., bipolar and multipolar, were noted. Bipolar cells had two primary processes emerging from the poles of an elongated soma. The mean length of these processes was 78.7 μm. These cells constituted 42.3% of the sample (n=105). Multipolar cells (54.3% of total) had a less elongated soma and extended 3–6 main processes whose mean length was 56.3 μm. These processes showed no preferred direction. The length of the primary processes of bipolar cells was 40% greater than that of multipolar cells (P〈0.02). Three cells (2.9%) had only one primary process. The DiI stain could be converted into a stable electron-opaque product. Electron-microscopic observations showed that these cells had the typical appearance of ICCs reported in previous studies. This staining method should be useful for physiological investigations of ICCs in gastrointestinal tissues.
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    Biochemical identification and tissue-specific expression patterns of keratins in the zebrafish Danio rerio (1998)
    Springer
    Cell & tissue research 293 (1998), S. 195-205 
    Details
    ISSN: 1432-0878
    Keywords: Key words Fish ; Zebrafish ; Immunocytochemistry ; Keratin ; Cytoskeleton ; Danio rerio (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  We have identified a number of type I and type II keratins in the zebrafish Danio rerio by two-dimensional polyacrylamide gel electrophoresis, complementary keratin blot-binding assay and immunoblotting. These keratins range from 56 kDa to 46 kDa in molecular mass and from pH 6.6 to pH 5.2 in isoelectric point. Type II zebrafish keratins exhibit significantly higher molecular masses (56–52 kDa) compared with the type I keratins (50–48 kDa), but the isoelectric points show no significant difference between the two keratin subclasses (type II: pH 6.0–5.5; type I: pH 6.1–5.2). According to their occurrence in various zebrafish tissues, the identified keratins can be classified into “E” (epidermal) and “S” (simple epithelial) proteins. A panel of monoclonal anti-keratin antibodies has been used for immunoblotting of zebrafish cytoskeletal preparations and immunofluorescence microscopy of frozen tissue sections. These antibodies have revealed differential cytoplasmic expression of keratins; this not only includes epithelia, but also a variety of mesenchymally derived cells and tissues. Thus, previously detected fundamental differences in keratin expression patterns between higher vertebrates and a salmonid, the rainbow trout Oncorhynchus mykiss, also apply between vertebrates and the zebrafish, a cyprinid. However, in spite of notable similarities, trout and zebrafish keratins differ from each other in many details. The present data provide a firm basis from which the application of keratins as cell differentiation markers in the well-established genetic model organism, the zebrafish, can be developed.
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    Ultrastructural correlates of the antidiuretic hormone-dependent and antidiuretic hormone-independent increase of osmotic water permeability in the frog urinary bladder epithelium (1998)
    Springer
    Cell & tissue research 293 (1998), S. 517-524 
    Details
    ISSN: 1432-0878
    Keywords: Key words Electron microscopy ; F-actin ; Freeze-fracture ; Immunocytochemistry ; Water permeability ; Antidiuretic hormone ; Urinary bladder ; Rana temporaria (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Electron and confocal microscopy, using immunocytochemical methods, was employed to assess osmotic water permeability of the frog (Rana temporaria) urinary bladder during transcellular water transport, induced by antidiuretic hormone (ADH) or by wash-out of autacoids from serosal, ADH-free Ringer solution. The increase of osmotic water permeability of the urinary bladder was accompanied by relevant ultrastructural changes, the most remarkable being: (1) the appearance of aggregates of intramembranous particles in the apical membrane of granular cells, and the extent of the membrane area covered by the aggregates proportional to that of the water flow; (2) redistribution of actin filaments in the cytoplasm of granular cells; judging from the anti-actin label density, the number of actin filaments in the apical region of cytoplasm was reduced by 2.5–4 times compared with normal; (3) a decrease in the total electron density of the cytoplasm due to the increased water content of granular cells.
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    Immunocytochemical localization and characterization of mammalian thyrotropin-like material in the pituitary of the Australian lungfish, Neoceratodus forsteri (1998)
    Springer
    Cell & tissue research 294 (1998), S. 515-523 
    Details
    ISSN: 1432-0878
    Keywords: Key words Mammalian-type thyrotropin ; Pituitary ; Immunocytochemistry ; Australian lungfish ; Neoceratodus forsteri (Dipnoi)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The binding sites of polyclonal antisera raised against the β-subunit of human thyroid-stimulating hormone (hTSHβ), hTSH, and ovine TSH (oTSH) have been localized in the pituitary gland of the Australian lungfish, Neoceratodus forsteri, using light microscopy. Reactivity toward anti-TSH antiserum was demonstrated in a slightly elongated and irregularly-shaped distinct cell type forming clusters in the dorso-central and ventral regions of the distal lobe. Their granules react with alcian blue (AB), and with periodic acid–Schiff (PAS), and after AB-PAS-orange G they stain blue or purple. The specificity of the different antisera was established by liquid-phase absorptions and confirmed in positive and negative tissue control systems. Our observations confirm that dipnoan (Neoceratodus) TSH shares a number of antigenic determinants with those of mammalian TSHβ and support the concept that mammalian TSHβ, or part of it, was established early in evolution, and that dipnoans (Neoceratodus) as living sarcopterygians may have an ancestor in common with the early amphibians. The mapping and detailed description of TSH-like immunoreactive cells may furnish a background to facilitate current and future analysis of the ontogeny and time course of TSH production and release in Neoceratodus in relation to different physiological conditions.
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    Callose deposition at plasmodesmata (1998)
    Springer
    Protoplasma 201 (1998), S. 30-37 
    Details
    ISSN: 1615-6102
    Keywords: Cell-to-cell communication ; Plasmodesmata ; Ultrastructure ; Wounding ; 2-Deoxy-D-glucose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The transport of ions and metabolites through plasmodesmata has been thought to be controlled at the neck region where the cytoplasmic annulus is constricted and where callose has also been localised. In order to determine the possible structural and functional effects of callose, its deposition was inhibited through incubation of the plant tissue with 2-deoxy-D-glucose (DDG) for 1 h prior to fixation in 2.5% glutaraldehyde. The inhibition of callose formation was monitored through aniline blue-induced fluorescence of callose. The neck region of the plasmodesmata fromAllium cepa L. roots treated with DDG exhibited a funnel-shaped configuration. This is in contrast to the plasmodesmata from tissue not incubated with DDG, which exhibited constricted necks similar to those previously reported. Both initial dissection and glutaraldehyde fixation induced neck constriction in plasmodesmata, however, dissection of tissue increased the frequency of constrictions. The inhibition of callose formation by chemical means showed that the neck constrictions and raised collars in this area are artefacts due to physical wounding and glutaraldehyde fixation. The external electron-dense material observed when tannic acid is included in the primary fixative appears to be unrelated to the deposition of callose at the neck region.
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    Unusual pattern of mitosis in the free-living flagellateDimastigella mimosa (Kinetoplastida) (1998)
    Springer
    Protoplasma 201 (1998), S. 101-109 
    Details
    ISSN: 1615-6102
    Keywords: Kinetochore ; Kinetoplastida ; Intranuclear microtubules ; Mitosis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The three-dimensional ultrastructural organization of the mitotic apparatus ofDimastigella mimosa was studied by computer-aided, serial-section reconstruction. The nuclear envelope remains intact during nuclear division. During mitosis, chromosomes do not condense, whereas intranuclear microtubules are found in close association with six pairs of kinetochores. No discrete microtubule-organizing centers, except kinetochore pairs, could be found within the nucleus. The intranuclear microtubules form six separate bundles oriented at different angles to each other. Each bundle contains up to 8 tightly packed microtubules which push the daughter kinetochores apart. At late anaphase only, midzones of these bundles align along an extended interzonal spindle within the narrow isthmus between segregating progeny nuclei. The nuclear division inD. mimosa can be described as closed intranuclear mitosis with acentric and separate microtubular bundles and weakly condensed chromosomes.
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    URL: http://dx.doi.org/10.1007/BF01280716
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    Physiological, structural, and immunological characterization of leaf and chloroplast development in cotton (1998)
    Springer
    Protoplasma 202 (1998), S. 23-37 
    Details
    ISSN: 1615-6102
    Keywords: Chloroplast development ; Cotton ; Fluorescence induction kinetics ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Many of the studies of chloroplast ontogeny in higher plants have utilized suboptimal conditions of light and growth to assess development. In this study, we utilized structural, immunological, and physiological techniques to examine the development of the chloroplast in fieldgrown cotton (Gossypium hirsutum cv. “MD 51 ne”). Our youngest leaf sample developmentally was completely folded upon itself and about 0.5 cm in length; leaves of this same plastochron were followed for three weeks to the fully expanded leaf. The chloroplasts at the earliest stage monitored had almost all of the lamellae in small, relatively electron-opaque grana, with relatively few thylakoids which were not appressed on at least one surface. During the development of the thylakoids, the membranes increase in complexity, with considerable stroma lamellae development and an increase in the number of thylakoids per granum. Besides the increase in complexity, both the size and numbers of the chloroplast increase during the development of the leaf. Developmental changes in six thylakoid proteins, five stromal proteins, and one peroxisomal protein were monitored by quantitative immunocytochemistry. Even at the earliest stages of development, the plastids are equipped with the proteins required to carry out both light and dark reactions of photosynthesis. Several of the proteins follow three phases of accumulation: a relatively high density at early stages, a linear increase to keep step with chloroplast growth, and a final accumulation in the mature chloroplast. Photosystem-II(PS II)-related proteins are present at their highest densities early in development, with an accumulation of other parts of the photosynthetic apparatus at a latter stage. The early accumulation of PS-II-related proteins correlates with the much lower ratio of chlorophylla tob in the younger leaves and with the changes in fluorescence transients. These data indicate that some of the conclusions on chloroplast development based upon studies of intercalary meristems of monocots or the greening of etiolated plants may not be adequate to explain development of chloroplasts in leaves from apical meristems grown under natural conditions.
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    URL: http://dx.doi.org/10.1007/BF01280872
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    Teliospores of smut fungi teliospore walls and the development of ornamentation studied by electron microscopy (1998)
    Springer
    Protoplasma 204 (1998), S. 170-201 
    Details
    ISSN: 1615-6102
    Keywords: Spores ; Ultrastructure ; Microbotryum ; Tilletia ; Tolyposporium ; Ustilago
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The walls of mature teliospores and the development of ornamentation, as seen by transmission electron microscopy, are described for 37 genera of smut fungi, based on observations of ca. 120 species and on literature. Structural diversity of mature teliospore walls is due to differences in spore wall layers forming the spore wall (endosporium, middle layer, exosporium, ornamentation) and to different elements forming the ornamentation (exosporium, ornaments, sheath, hyphal wall, adjacent fungal cells, material of the host). During teliosporogenesis the outer layers are usually deposited first. At the beginning of the formation of the ornamentation the plasma membrane may be smooth or undulated carrying the developing ornaments on its tips or in its depressions. The ornamentation of some genera appears similar when seen by scanning electron microscopy, but can be the product of different developmental patterns (e.g., warts of species ofFarysia, Tilletia, andUstilago), however, warty and reticulate ornamentation can both be produced by similar developmental processes (shown, e.g., for species ofCintractia andTilletia). Typical structures of the mature teliospore wall and developmental patterns based on homologous similarities are described for the following groups of genera or species:Macalpinomyces, Melanopsichium, Sporisorium, andUstilago infecting members of the family Poaceae;Kuntzeomyces, Testicularia, andTrichocintractia; Anthracoidea, Cintractia, Heterotolyposporium piluliforme, andTolyposporium junci; Glomosporium, Sorosporium, andThecaphora; Conidiosporomyces, Erratomyces, Ingoldiomyces, Neovossia, Oberwinkleria, andTilletia; Entyloma, and genera of the Doassansia group;Liroa, Microbotryum, Sphacelotheca, Ustilago infecting dicotyledons, andZundeliomyces; Aurantiosporium, Fulvisporium, andUstilentyloma. Special characteristics of the teliospore wall were observed for the generaDermatosorus, Doassinga, Entorrhha, Farysia, Mycosyrinx, Rhamphospora, and some species ofTolyposporium.
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    Teliospores of smut fungi teliospore connections, appendages, and germ pores studied by electron microscopy; phylogenetic discussion of characteristics of teliospores (1998)
    Springer
    Protoplasma 204 (1998), S. 202-218 
    Details
    ISSN: 1615-6102
    Keywords: Spore balls ; Germ areas ; Ultrastructure ; Phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Special features of teliospores in smut fungi are described, including teliospore connections, appendages, and germ pores. Balls of teliospores in species of many different genera cohere by remnants of hyphal walls, sheaths, and sometimes interlocking ornamentation. Teliospores are connected in pairs in species ofMycosyrinx andGeminago by special local structures. Appendages can be formed locally by persistent material from the sheath (Cintractia, Anthracoidea, Sphacelotheca), thickened parts of the spore wall (e.g.,Georgefischeria, Jamesdicksonia, Rhamphospora, Tolyposporella), or persistent walls of sporogenous hyphae (Rhamphospora, genera of the Tilletia relationship). Species ofGeorgefischeria, Jamesdicksonia, andTolyposporella have teliospore walls composed of more than three layers of different electron density. “Germ areas” corresponding to thinner parts of the spore wall are known, e.g., for species ofAnthracoidea, Cintractia, andUstilago infecting members of the family Poaceae, while distinct germ pores, one per teliospore, are found in some species ofThecaphora, “Tolyposporium”, andSporisorium. Teliospores ofMycosyrinx cissi have a germination ring. Characteristics of teliospores are used to discuss the phylogeny of smut fungi. A phylogenetic tree in accordance with teliospore characteristics is compared to those obtained from ultrastructural characteristics of host-parasite interaction, of septal pores, and from sequence data. Aspects of teliospore development help to define taxa at a high systematic level (Entorrhizales, Ustilaginales, Tilletiales/Entylomatales, Microbotryaceae), while details of ornamentation ontogeny delimit groups of genera (e.g., genera related toUstilago on members of the Poaceae andSporisorium, Cintractia andAnthracoidea, Tilletia) or single genera (e.g.,Melanopsichium, Dermatosorus, Mycosyrinx, Doassinga, Rhamphospora). Types of ornamentation (warty, reticulate), middle layers, teliospore balls, and germ pores evolved repeatedly by convergence. The smut teliospore itself probably evolved independently at least twice, or perhaps three (or more) times, in the Microbotryales, in the Entorrhizales, and in a common ancestor of the remainder of the Ustilaginomycetes.
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    Megagametophytes of Douglas fir (Pseudotsuga menziesii) and hybrid larch (Larix × eurolepis) in culture: Multiplication of neck cells and the formation of binucleate cells (1998)
    Springer
    Protoplasma 204 (1998), S. 219-225 
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    ISSN: 1615-6102
    Keywords: Neck cell proliferation ; Binucleate ; Douglas fir ; Conifers ; Genetic instability ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary To study the effect of culturing on megagametophytes of Douglas fir (Pseudotsuga menziesii) and hybrid larch (Larix × eurolepis), cones were collected at the time of fertilization and the megagametophytes were removed, then placed on medium. We used a modified Murashige and Skoog medium supplemented with 5% lactose and 10% polyethylene glycol 4000. A variety of cell types proliferated including prothallial, neck, and jacket cells. Some of these multiplying cells showed a binucleate condition. The prothallial cells of the apex divided and expanded. The neck cells formed clusters composed of more cells than normally found in situ; though otherwise they showed ultrastructural similarity to neck cells in situ. These neck cells had large numbers of active Golgi complexes, numerous large and small vacuoles, coated vesicles, smooth vesicles, a well-developed endoplasmic reticulum, and thickened cell walls. These are the first reports of neck cell multiplication and induction of a binucleate state for gymnosperm megagametophyte cells in vitro.
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    Immunolocalization of ferritin in determinate and indeterminate legume root nodules (1998)
    Springer
    Protoplasma 204 (1998), S. 61-70 
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    ISSN: 1615-6102
    Keywords: Ferritin ; Nitrogen fixation ; Nodule development ; Plastid ; Legume ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In eukaryotic organisms ferritin is a protein involved in the storage of iron. The occurrence of ferritin and its relationship to the effectiveness of the nitrogen-fixing activity have been previously studied during the early stages of the nodule development by biochemical methods. We have used immunocytochemistry techniques to determine the precise location of ferritin and the behavior of this protein along the nodule development. The major localization was found in plastids and amyloplasts of infected and uninfected cells of the three legume nodules studied. A decrease of the immunolabelling was observed in infected cells of lupin and soybean senescing nodules and in the senescent zone of indeterminate alfalfa nodules. In the cortex of soybean and lupin nodules, ferritin increased during nodule ageing and the immunogold particles were mainly located in crystalline structures. The putative role of ferritin and plastids during nodule development is discussed.
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    Subcellular localization of glycoprotein epitopes during the development of lupin root nodules (1998)
    Springer
    Protoplasma 201 (1998), S. 71-84 
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    ISSN: 1615-6102
    Keywords: Lupinus albus ; Nitrogen fixation ; Oxygen diffusion ; Glycoprotein ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The monoclonal antibodies MAC236 and MAC265, raised against a soluble component of pea nodules, were used to elucidate the presence and subcellular localization of glycoprotein epitopes during the development of lupin (Lupinus albus L. cv. Multolupa) nodules, by means of immunocytochemistry and Western blot analysis. These antibodies recognize a single band of 95 kDa in pea, soybean and bean nodules, whilst two different bands of 240 and 135 kDa cross-react with MAC236 and MAC265 respectively in lupin nodules. This fact may indicate that the recognized epitopes can be present in different subcellular compartments and/or play different roles through the development of functional nodules. The results show that MAC265 is mainly associated with Bradyrhizobium infection and with the development of nodule primordium, in the first stages of nodulation. MAC265 is also detected when glycoprotein transport takes place across the cytoplasm and the cell wall, and also in the intercellular spaces of the middle cortex, attached to cell walls. The amount of MAC265 remains constant through nodule development. In contrast the amount of MAC236 increases with nodule age, parallel to the establishment of nitrogenase activity. This antibody is localized in cytoplasmic globules attached to the inner side of cell walls in the middle cortex, and mainly in the matrix filling the intercellular spaces of the middle and inner cortex. This main site of localization of MAC236 may indicate a role in the functioning of the oxygen diffusion barrier.
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    Teliospores of smut fungi general aspects of teliospore walls and sporogenesis (1998)
    Springer
    Protoplasma 204 (1998), S. 155-169 
    Details
    ISSN: 1615-6102
    Keywords: Spores ; Ultrastructure ; Entorrhiza ; Microbotryum ; Tilletia ; Ustilago
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The concept and nomenclature for the elements of teliospore walls in smut fungi are presented and a survey of teliosporogenesis is given, as seen by light and transmission electron microscopy. Four developmental types are distinguished: the Ustilago, Microbotryum, Tilletia, and Entorrhiza type. In the Ustilago type, sporogenous hyphae are completely segmented into teliospore initials which are embedded in a hyaline matrix formed by gelatinised hyphal walls (found in species ofAnthracoidea, Cintractia, Heterotolyposporium, Kuntzeomyces, Macalpinomyces, Melanopsichium, Sporisorium, Testicularia, Tolyposporium junci, Trichocintractia, and species ofUstilago infecting members of the family Poaceae). In the Microbotryum type, septate sporogenous hyphae are also completely segmented into teliospore initials, however, they are not surrounded by a hyaline matrix (Microbotryum, Sphacelotheca, Ustilago spp. infecting dicotyledons). A yeast-like budding of teliosporogenic cells is observed for some species ofMicrobotryum, Sphacelotheca, andUstilago infecting dicotyledons. In the Tilletia type, teliospores differentiate locally in the sporogenous hyphae, in an apical or intercalary position, without a hyaline matrix (Conidiosporomyces, Doassinga, Entyloma, Erratomyces, Ingoldiomyces, Neovossia, Oberwinkleria, Rhamphospora, Tilletia). In all these types, the teliospore initials first develop a hyaline sheath under which the ornamentation, the exosporium, sometimes a middle layer, and the endosporium are successively deposited by the fungal cell. In the Entorrhiza type, the teliospores develop inside vital host cells with the wall of the sporogenous hypha included into the teliospore wall. The fungus develops a middle layer and an electron-transparent endosporium inside the hyphal wall while a layer forming the ornamentation is deposited onto the hyphal wall, probably by vesicles of dictyosomes of the host cell.
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    Immunolocalization of β-(1→4) and β-(1→6)-D-galactan epitopes in the cell wall and Golgi stacks of developing flax root tissues (1998)
    Springer
    Protoplasma 203 (1998), S. 26-34 
    Details
    ISSN: 1615-6102
    Keywords: Flax ; Cell wall ; Golgi apparatus ; β-Galactans ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Most cell wall components are carbohydrate including the major matrix polysaccharides, pectins and hemicelluloses, and the arabinogalactan-protein proteoglycans. Both types of molecules are assembled in the Golgi apparatus and transported in secretory vesicles to the cell surface. We have employed antibodies specific to β-(1→6) and β-(1→4)-D-galactans, present in plant cell wall polysaccharides, in conjunction with immunofluorescence and electron microscopy to determine the location of the galactan-containing components in the cell wall and Golgi stacks of flax root tip tissues. Immunofluorescence data show that β-(1→4)-D-galactan epitopes are restricted to peripheral cells of the root cap. These epitopes are not expressed in meristematic and columella cells. In contrast, β-(1→6)-D-galactan epitopes are found in all cell types of flax roots. Immunogold labeling experiments show that both epitopes are specifically located within the wall immediately adjacent to the plasma membrane. They are also detected in Golgi cisternae and secretory vesicles, which indicates the involvement of the Golgi apparatus in their synthesis and transport. These findings demonstrate that the synthesis and localization of β-(1→4)-D-galactan epitopes are highly regulated in developing flax roots and that different β-linked D-galactans associated with cell wall polysaccharides are expressed in a cell type-specific manner.
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    Cytomorphological characters supporting the taxonomic validity ofCyanothece (Cyanoprokaryota) (1998)
    Springer
    Plant systematics and evolution 210 (1998), S. 25-39 
    Details
    ISSN: 1615-6110
    Keywords: Cyanophyta ; Cyanobacteria ; Cyanothece ; Synechococcus ; Cyanobium ; Ultrastructure ; nucleoids ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The fine structure of the type species of the genusCyanothece Komárek 1976,C. aeruginosa, is described and compared with the main cytological characteristics of morphologically related members of the generaCyanobium, Cyanobacterium andSynechococcus. Several morphological features, such as cell walls with thick outer layers containing a special type of vesicles, position of thylakoids, “keritomy” (net-like appearance of protoplast caused by arrangement of thylakoids, net-like nucleoids and/or by tendency to form intrathylakoidal spaces) and a special structure of mucilaginous envelopes were found to be characteristic of this genus, supporting its separate position among coccal cyanoprokaryotes (cyanobacteria, cyanophytes). The taxonomic significance of ultrastructural features in all mentioned genera is discussed.
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    Ultrastructure of the endolymphatic sac in the larva of the Japanese red-bellied newt Cynops pyrrhogaster (1998)
    Springer
    Cell & tissue research 291 (1998), S. 549-559 
    Details
    ISSN: 1432-0878
    Keywords: Key words Endolymphatic sac ; Ultrastructure ; Fluid transport ; Otoconia ; Newt ; Cynops pyrrhogaster (Urodela)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The ultrastructure of the endolymphatic sac (ES) of the late stage larva of the Japanese red-bellied newt, Cynops pyrrhogaster (stage 57), was examined by light and transmission electron microscopy. The two endolymphatic sacs are located at the dorsal-medial side of the otic vesicle on the dorsal-lateral side of the midbrain in the cranial cavity. The wall of the sac is composed of a layer of cubical epithelial cells with loose, interposed intercellular spaces. The sac contains a large luminal cavity, in which endolymph and numerous otoconia are present. The epithelial cells of different portions of the sac have a similar structure. These cells contain an abundance of cytoplasmic organelles, including ribosomes, Golgi complexes, and numerous vesicles. Two types of vesicles are found in the epithelial cells: the “floccular” vesicle and the “granular” vesicle. The floccular vesicles are located in the supra- and lateral-nuclear cytoplasm and contain flocccular material. The granular vesicles have a fine granular substance and are usually situated apposed to the apical cell membrane. The granular vesicles are suggested to be secreted into the lumen, while the floccular vesicles are thought to be absorbed from the lumen and conveyed to the intercellular spaces by the epithelial cells. The apical surfaces of the epithelial cells bear numerous microvilli. Apparently floating cells, which bear long microvilli on the free surfaces, are observed in the lumen of the ES. Based on the fine structure, the function of the endolymphatic sac of the newt Cynops pyrrhogaster is discussed.
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    In situ characterization of mast cells in the frog Rana esculenta (1998)
    Springer
    Cell & tissue research 292 (1998), S. 151-162 
    Details
    ISSN: 1432-0878
    Keywords: Key words Histamine ; Immunocytochemistry ; Mast cells ; Melanocytes ; Nerves ; Rana esculenta (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The number, distribution, and ultrastructural characteristics of mast cells were assessed in the tongue, heart, and kidney of the frog Rana esculenta. The density of tongue mast cells (253±45 mast cells/mm2) was significantly higher than that of the heart (5.3±0.4/mm2) and kidney (15.3±1.4 /mm2). A striking feature of this study was the remarkable association of frog mast cells to nerves. The ultrastructural study of the mast cell/nerve association demonstrated that mast cells were closely apposed to or even embedded in nerves. Mast cells were also physically associated with melanocytes even in the heart. Mast cells were Alcian blue+/safranin+ in the tongue and in the peritoneum, whereas in the heart and in the kidney they were Alcian blue–/safranin+. The mast cells in the lamina propria of the gastrointestinal tract were Alcian blue+/safranin–. The cytoplasm of frog mast cells was packed with numerous heterogeneous, membrane-bound granules. The ultrastructure of these cytoplasmic granules was unique, being totally unlike any other previously described granules in other animal species as well as in man. The histamine content/frog mast cell (≈0.1 pg/cell) was approximately 30 times lower than that of human mast cells isolated from different tissues (≈3 pg/cell). A monoclonal anti-histamine antibody was used to confirm the ultrastructural localization of histamine in secretory granules in frog mast cells.
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    Convoluted cords, a new nuclear body in spermatocytes and spermatids of the rabbit (1998)
    Springer
    Cell & tissue research 293 (1998), S. 349-355 
    Details
    ISSN: 1432-0878
    Keywords: Key words Germ cells ; Nucleus ; Ribonucleoproteins ; Immunocytochemistry ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The convoluted cords present in the nuclei of rabbit primary spermatocytes and spermatids differ from previously described nuclear bodies. They are composed of proteic strands decorated with granules and, in most cases, are embedded in clusters of interchromatin granules. They are partly sensitive to trypsin and can be visualised with protein-specific stains. The decorating granules are similar in size and aspect to interchromatin granules. However, only the latter are continuously immunolabelled with anti-snRNPs (small ribonucleoproteins) antibodies during spermatogenesis. The complexity and organisation of the convoluted cords are modified specifically during cell differentiation. They might be involved in the storage, transport and release of interchromatin granules in male germ cells.
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    Distribution of tachykinin-related neuropeptide in the developing central nervous system of the moth Spodoptera litura (1998)
    Springer
    Cell & tissue research 294 (1998), S. 351-365 
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    ISSN: 1432-0878
    Keywords: Key words Insect nervous system ; Immunocytochemistry ; Neural development ; Neuropeptide ; Neurohormone ; Locustatachykinin ; Spodoptera litura (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Neuropeptides with similarities to vertebrate tachykinins, designated tachykinin-related peptides (TRPs), have been identified in several insect species. In this investigation we have utilized an antiserum raised to one of the locust TRPs, locustatachykinin-I (LomTK-I), to determine the distribution pattern of LomTK-like immunoreactive (LTKLI) neurons in the developing nervous system of the moth Spodoptera litura. A number of LTKLI neurons could be followed from the larval to the adult nervous system: a set of median neurosecretory cells (MNCs) in the brain, a pair of brain descending neurons and a few sets on neurons in the ventral nerve cord. The distribution of LTKLI neurons in the adult brain is very similar to that seen in other insect species with prominent arborizations in the central body, antennal lobes, mushroom body calyces, optic lobe neuropils and other distinct neuropil areas in the protocerebrum and tritocerebrum. A new finding is the presence of LTKLI neurosecretory cells with axon terminals in the anterior aorta and corpora cardiaca, suggesting for the first time a neurohormonal role of tachykinin-related peptide(s) in insects. During postembryonic development the number of LTKLI neurons in the ventral nerve cord decreases somewhat, whereas the number increases in the brain. Thus the functional roles of TRPs may change to some extent during development.
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    Remodeling of neural, glial, and tracheal cell populations in the developing Manduca wing (1998)
    Springer
    Cell & tissue research 294 (1998), S. 367-375 
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    ISSN: 1432-0878
    Keywords: Key words Neurons ; Glia ; Tracheae ; Wing ; Ultrastructure ; Moth ; Manduca sp.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  This ultrastructural examination of sensory nerves of the Manduca wing has revealed that extensive remodeling occurs among insect sensory neurons and their associated glial cells between pupation and adult emergence. Systematic counts of axons in particular wing nerves throughout adult development have shown that a decrease in axon number per nerve occurs after day 6. The neurons and glial cells that die are believed to be cells present at pupation that have no apparent sensory function but that probably function as guidance scaffolding for neurons and glia that are born after pupation. Despite the loss of several axons from each wing nerve, these nerves continue to grow in diameter during the latter half of adult development as some of the surviving axons increase severalfold in diameter. Each growing wing nerve in turn apparently functions as a scaffold for the proximal to distal growth of adult tracheae. A correspondence exists between adult nerve pathways and adult tracheal pathways, with each trachea maintaining intimate contact with a wing nerve along its entire length.
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    Mechanical isolation and ultrastructural characterization of viable egg cells in Plumbago zeylanica (1997)
    Springer
    Sexual plant reproduction 10 (1997), S. 368-373 
    Details
    ISSN: 1432-2145
    Keywords: Key words Egg-cell isolation (angiosperm) ; Micromanipulation ; Plumbagozeylanica ; Viable egg ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A protocol for isolating viable eggs in Plumbago zeylanica by mechanical dissection is reported. The optimum solution for isolation was 0.8 M mannitol + 10 mM MOPS + 10 mM CaCl2, (pH 4.5–5.0) with an osmolality of 860–940 mmol/kg. Eggs retain their viability for at least 24 h. Isolated eggs were true protoplasts without cell walls and could tolerate osmolality of 437 mmol/kg to 965 mmol/kg. Observation of the isolated eggs using transmission electron microscopy indicated that they were well preserved and reflected the ultrastructure of physiologically active cells, displaying features similar to those of in vivo egg cells. Notable differences include the absence of a filiform apparatus and the accumulation of dense particles in the plastids, which was most conspicuous in egg cells that were damaged during isolation.
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    URL: http://dx.doi.org/10.1007/s004970050111
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    An ultrastructural study of the mature spermatozoid of the fern Asplenium trichomanes L. subsp. trichomanes (1997)
    Springer
    Sexual plant reproduction 10 (1997), S. 142-148 
    Details
    ISSN: 1432-2145
    Keywords: Key words Asplenium trichomanes L. subsp. trichomanes ; Ferns ; Spermatozoids ; Flagella ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Asplenium trichomanes L. subsp. trichomanes spermatozoids are spirals of about five turns. Keels link the elements of the microtubular ribbon with the plates of the lamellar layer (LL) which are uninterrupted, parallel and curved with an inner angle of about 150°. Electron-opaque filaments connect the microtubules of the multilayered structure (MLS) and the osmiophilic crest, the LL and the MLS-associated mitochondrion and the latter and the plasmalemma. The nucleus occupies the 2.5–3 posterior turns and has an inner honeycomb-shaped chromatin mass and an outer highly condensed chromatin mass with randomly scattered electron-transparent areas. The basal bodies of the ca. 50 flagella are bounded by a reticulum of granular material which forms a plug inside their proximal region; the proximal region of the flagellum has a 9 + 0 pattern. The axoneme has a 9 + 2 pattern.
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    URL: http://dx.doi.org/10.1007/s004970050081
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    Ultrastructural study of the proboscis endothelium of Riseriellus occultus (Nemertea, Heteronemertea) (1997)
    Springer
    Hydrobiologia 365 (1997), S. 121-127 
    Details
    ISSN: 1573-5117
    Keywords: Riseriellus occultus ; Heteronemertea ; Proboscis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have examined with transmission electron microscopythe epithelial layer exposed to the rhynchocoel fluidof the proboscis in the heteronemertine Riseriellus occultus. This epithelium is organized asa monociliated, pseudostratified myoepitheliumconsisting of two cell types: apically situatedmonociliated supportive cells and subapical myocyteslacking cilia. The low supportive cells form acontinuous adluminal sheet and reach with numerouscytoplasmic processes into the extracellular matrix;these cells are characterized by numerous, irregularlyshaped, apical folds projecting into the rhynchocoelfluid, delimiting broad extracellular spaces. Theauthors suppose that both apical and basal folds couldaccommodate stretching of the endothelium when theproboscis is everted. The apical folds of thesupportive cells increase the interface of these withthe rhynchocoel fluid; this feature, together with thepresence of pinocytotic vesicles in such cells,suggest that they could be involved in the exchange ofsubstances between the rhynchocoel fluid and theproboscis. The myocytes are scattered singly withinthe monociliated pseudostratified myoepithelium. Theyare situated between the supportive cells and thesubjacent extracellular matrix. Basement membraneseparating both cells types is lacking. Myofibrillarparts protrude basally from the myocyte somata. Themyofibrillar parts lie in direct apposition to theextracellular matrix, and are oriented circular to thelongitudinal axis of the proboscis. We consider themyocytes to be intra-epithelial, myoepithelial cells.
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    Mucosal surface area in chicken small intestine during development (1997)
    Springer
    Cell & tissue research 290 (1997), S. 71-78 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Development ; Mucosal surface area ; Ultrastructure ; Villus ; Microvillus ; Morphometric analysis ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The mucosal surface area of the chicken duodenum, jejunum, and ileum was determined during development (from 1-day to 12-week-old animals). The morphometric analysis was performed at three magnification levels. The nominal (serosal) surface area was determined at the macroscopic level, from intestinal length and perimeter. Villus and microvillus amplification factors were estimated at light-microscopic and transmission electron-microscopic levels, respectively. The results show, during the period considered: (1) a similar increase in nominal surface area for the three segments (6.5 to 7.2-fold), (2) a rise followed by a slight decrease in the villus amplification factor in the third week of age in the duodenum, a two-fold increase of this variable in the jejunum and no significant developmental variations in the ileum, (3) an increase in the microvillus amplification factor of 1.5-fold in the duodenum and jejunum and of 1.2-fold in the ileum, although a pronounced decrease in the first week of age was observed in the three segments. In conclusion, total mucosal surface area increased, from 1 day to 12 week, 12- to 13-fold in the duodenum and ileum and 20-fold in the jejunum.
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    Occurrence of enzymes of free radical metabolism suggests the possible cytotoxic capacity of the transitional epithelium of the human ureter (1997)
    Springer
    Cell & tissue research 287 (1997), S. 351-356 
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    ISSN: 1432-0878
    Keywords: Key words: Urothelium ; Tartrate-resistant acid phosphatase ; Nitric oxide synthase I ; Superoxide dismutase ; Immunocytochemistry ; Free radicals ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Three enzymes, viz., tartrate-resistant acid phosphatase (TRAP), nitric oxide synthase I (NOS-I), and superoxide dismutase (SOD), involved in the production and metabolism of free radicals or radical equivalents, were demonstrated by immunocytochemistry in the urothelium of the ureters of six patients of various ages. Two of these enzymes (TRAP and NOS-I) were colocalized in the most apical and lateral border of the superficial cells of the urothelium. In contrast, SOD showed a patchy or granular distribution within the supranuclear region of these cells. Intra- and subepithelial macrophages exhibited a weak TRAP, but no NOS-I or SOD, immune reaction. On the basis of the immunocytochemical findings, arguments in favor of a cytotoxic function of the superficial cells of the human urothelium are presented.
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    Immunocytochemical analysis of the transport of arginine analogues into nitrergic neurons and other cells in the retina and pituitary (1997)
    Springer
    Cell & tissue research 290 (1997), S. 501-514 
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    ISSN: 1432-0878
    Keywords: Key words: Arginine ; Analogues ; Immunocytochemistry ; Nitric oxide ; Pituitary ; Retina ; Transport ; Rat (Wistar) ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Nitric oxide is formed by the action of nitric oxide synthase upon l-arginine. The efficacy of some exogenously applied arginine analogues in inhibiting nitric oxide synthase and thus nitrergic transmission indicates that neurons producing nitric oxide may possess an arginine transport system. To investigate whether arginine analogues are preferentially transported into nitric oxide-utilising cells or into cells making other neurochemicals, we have raised highly specific antisera against a number of arginine analogues including NG-methyl arginine, d-arginine, NGnitro-l-arginine, NG-nitro-l-arginine methyl ester and canavanine. Retinae were incubated in physiological media containing these analogues and rats were given intraperitoneal injections of the analogues to study the pituitary. Immunocytochemistry and NADPH-diaphorase histochemistry revealed that many of these analogues could be transported preferentially, but not exclusively, into nitric oxide-generating cells. However, some nitric oxide-producing cells apparently lacked the ability to take up some arginine analogues. We conclude that nitric oxide-generating cells in the retina and pituitary possess one or more arginine transporters. Other subsets of neurons that use GABA or glutamate as a neurotransmitter may also accumulate arginine analogues, possibly as a substrate for formation of these neurochemicals.
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    The peroxisomes of the hepatopancreas in two species of chitons (1997)
    Springer
    Cell & tissue research 290 (1997), S. 655-664 
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    ISSN: 1432-0878
    Keywords: Key words: Peroxisomes ; Ultrastructure ; Digestive gland ; Acanthochiton crinita ; Lepidochitona cinerea (Mollusca ; Polyplacophora)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract . This paper presents the first description of peroxisomes in polyplacophorans. As in other molluscs, the hepatopancreas of chitons is composed of basophilic and digestive cells. In the basophilic cells, the endoplasmic reticulum is abundant and several Golgi stacks can be observed. These cells also possess secretion granules and vacuoles with spherites. The digestive cells are mainly characterized by the presence of many food vacuoles. Several peroxisomes were observed in the basophilic cells of Acanthochiton crinita, most of them almost spherical. The matrix is filled with tubular structures and a crystalline nucleoid is also present in these organelles. In the digestive cells of A. crinita, peroxisomes are also almost spherical and possess two kinds of nucleoids. One of them presents a diamond shape and a bundle of tubular structures forms a second kind of nucleoid, which shows an elongated form. In Lepidochitona cinerea, the peroxisomes of basophilic cells are spherical or oval. Within the matrix, a cluster of dense rods and a prismatic nucleoid were observed. In the digestive cells of this species, almost spherical or oval peroxisomes are common, but they are smaller than the peroxisomes of the preceding cells. Nucleoids were not detected, but a few dense rods could be observed in the matrix. In both cell types of the two species, catalase activity was detected in the peroxisomal matrix. In addition, the elongated nucleoid of A. crinita digestive-cell peroxisomes and the nucleoid of L. cinerea basophilic-cell peroxisomes also present catalase activity.
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    Crustacean hyperglycaemic hormone in the nervous system of the primitive crustacean species Daphnia magna and Artemia salina (Crustacea: Branchiopoda) (1997)
    Springer
    Cell & tissue research 287 (1997), S. 565-576 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Crustacean hyperglycaemic hormone ; Immunocytochemistry ; Neurohaemal organ ; Daphnia magna ; Artemia salina (Crustacea)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Crustacean hyperglycaemic hormone-immunoreactive neuronal systems are detected in the central and peripheral nervous systems of two entomostracan crustaceans, Daphnia magna and Artemia salina, by immunocytochemistry using specific antisera against crustacean hyperglycaemic hormones of the decapod crustaceans Orconectes limosus and Carcinus maenas. In D. magna, four small putative interneurones are detected in the brain. In the thorax, ten bipolar peripheral neurones are stained by both antisera. They are obviously segmental homologues with centrally projecting axons that form interdigitating varicose fibres and terminals in putative neurohaemal areas next to the surface of the anterior part of the thoracic ganglia. Similar immunopositive neurones occur both in the central and peripheral nervous systems of A. salina. A total of five groups of neurones occur in the protocerebrum, the deutocerebrum and the mandibular ganglion. Some of the protocerebral neurones are bipolar and project to the dorsal frontal organ. A single pair of peripheral multipolar neurones in the maxillary segment projects centrally into the ventral nerve cord and innervates unidentified somatic muscles and tissues in the maxillary and the first appendage segments. None of the brain neurones in both species show similarities to decapod X-organ sinus gland neurosecretory neurones. Chromatography of brain extracts of D. magna combined with immunodot blotting revealed two strongly immunoreactive fractions at retention times close to that of the crustacean hyperglycaemic hormone of crayfish. Moreover, preabsorption controls suggest that the cross-reacting peptides of D. magna and A. salina are structurally closely related to those of decapods.
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    Immunolocalization of Bcl-xL/S in the central nervous system of neonatal and adult rats (1997)
    Springer
    Cell & tissue research 288 (1997), S. 59-68 
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    ISSN: 1432-0878
    Keywords: Key words: Apoptosis ; Neuronal plasticity ; Hypothalamus ; Astrocytes ; Immunocytochemistry ; Western blot ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. A polyclonal antibody raised against a peptide corresponding to the (2–19) amino-terminal sequence of the Bcl-xL/S protein was used to localize Bcl-x immunostaining in the central nervous system of rats at various postnatal ages. Whereas Bcl-x immunostaining was present in virtually all neurons of young animals (4 days postnatal), this staining became progressively restricted during the course of postnatal development. In adults, Bcl-x immunostaining was particularly strong in certain neurons present in a few hypothalamic nuclei, such as the supraoptic or the arcuate nuclei. Moderate staining was observed in some discrete brain regions, such as the olfactory bulb, the hippocampus, some catecholaminergic nuclei of the brainstem, and the cerebellum. Strong Bcl-x immunostaining was also exhibited in axon-like fibers located in the pyriform cortex, the median eminence, the dorsal medulla oblongata, and spinal cord. Bcl-x immunostaining was also present in astrocytes scattered throughout the white matter in the brain and the spinal cord, but was absent from those located in gray matter. Staining was particularly strongly expressed in reactive astrocytes densely packed along the borders of a central lesion or surrounding them, and in a large number of reactive astrocytes detected at a distance from the lesion. Our data suggest that, in addition to the possible stimulating effects on cell survival generally ascribed to Bcl-x, its maintained expression throughout adulthood or its re-expression following injury characterizes those neuronal or non-neuronal cells of the adult central nervous system that synthesize a range of molecules enabling them to adapt rapidly and successfully to a changing environment.
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    Distribution of FMRFamide-like immunoreactivity in the nervous system of Lumbricus terrestris (1997)
    Springer
    Cell & tissue research 288 (1997), S. 575-582 
    Details
    ISSN: 1432-0878
    Keywords: Key words: FMRFamide ; Immunocytochemistry ; Central nervous system ; Lumbricus terrestris (Annelida)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The distribution of FMRFamide-like immunoreactive cell bodies and fibers in the nervous system of the earthworm Lumbricus terrestris has been studied by means of immunocytochemistry. The cerebral ganglion contains 150–170 immunoreactive nerve cells that are organized into six major groups in the rostral and five major groups in the caudal part of the ganglion; 160–180 immunoreactive nerve cells are present in the subesophageal ganglion, and 80–90 in the ventral cord ganglia. Immunoreactive neurons of the subesophageal and the ventral cord ganglia show similar distributions, in that FMRFamide-like immunoreactive cells form a ventromedial and a lateral cell group. Neuropil in all parts of the central nervous system shows intensively stained varicose and non-varicose fibers. Each segmental nerve contains FMRFamide-like immunoreactive fibers that can partly be traced to the two muscle layers of the body wall, and a fine immunoreactive network lies among the muscle fibers. A similar network is found in the wall of the alimentary canal. Immunopositive perikarya and fibers have been detected in the prostomial nerves, in the stomatogastric system. Some epithelial cells of the body wall are also immunopositive. The morphological characteristics and localization of FMRFamide immunoreactive neurons suggest that they may be involved in: (1) central integratory processes; (2) neuromuscular regulation in both the body wall and enteric system; (3) sensory processes.
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    Development and organization of the retinal dopaminergic system of Ichthyophis kohtaoensis (Amphibia; Gymnophiona) (1997)
    Springer
    Cell & tissue research 289 (1997), S. 265-274 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Retina ; Amacrine cells ; Neurotransmitters ; Immunocytochemistry ; Tyrosine hydroxylase ; Dopamine ; Ichthyophis kohtaoensis (Gymnophiona)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Ichthyophis kohtaoensis, a member of the limbless Gymnophiona, has a specialized subterranean burrowing mode of life and a predominantly olfactory-guided orientation. The only visually guided behavior seems to be negative phototaxis. As these animals possess extremely small eyes (only 540 μm in diameter in adults), functional investigations of single retinal cells by electrophysiological methods have so far failed. Therefore, the content and distribution of retinal transmitters have been investigated as indications for a functioning sense organ in an animal that is supposed to be blind. In this study, the organization and development of the dopaminergic system have been examined in the retinae of embryonic, larval, and adult I. kohtaoensis, by using an antiserum against tyrosine hydroxylase, the rate-limiting enzyme in the catecholamine synthetic pathway, and an antiserum against dopamine itself. Labeled somata are situated in the inner nuclear layer and in the ganglion cell layer. Dopamine-positive fibers form a dense diffuse plexus, that covers the whole inner plexiform layer, whereas tyrosine hydroxylase-immunoreactive processes show a tendency to arborize in a stratified manner. Tyrosine-hydroxylase-immunolabeled fibers can occasionally be observed in the optic nerve head of larval stages. During ontogenesis and larval development, the distribution of transmitter-expressing cells changes and their number decreases, but no general degeneration of the visual system is detectable. Adult Ichthyophis still have retinal transmitters, indicating that the eyes, although obviously playing a minor role in a subterranean ecological niche, retain all the elements of functioning sense organs.
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    Immuno-electron microscopy reveals that the excitotoxin quinolinate is associated with the plasma membrane in human peripheral blood monocytes/macrophages (1997)
    Springer
    Cell & tissue research 290 (1997), S. 633-639 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Quinolinic acid ; Interferon-γ ; Kynurenine ; Electron microscopy ; Immunocytochemistry ; Excitotoxicity ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract.  Quinolinate (QUIN), a tryptophan-derived excitotoxin, was localized ultrastructurally in human peripheral blood monocytes/macrophages (MØ) by immuno-electron microscopy. A combined carbodiimide/glutaraldehyde/paraformaldehyde-based fixation procedure was developed for optimal retention of QUIN in the cell as well as minimal loss of ultrastructure; a silver-enhanced colloidal gold detection system was used for electron-microscopic analysis. Gold particles representing QUIN immunoreactivity were associated with the inner side of the plasma membrane in normal MØ. The number of gold particles increased significantly when QUIN levels were elevated by treatment with its precursor kynurenine, but location of the gold particles remained essentially the same under this condition. Treatment with interferon-γ increased the number of Golgi bodies, vacuoles and pseudopodia, reflecting the activated state of the cell. Significantly increased numbers of gold particles representing QUIN were detectable in approximately the same location as in the case of kynurenine treatment. Combined treatment with kynurenine and interferon-γ maximally increased the number of gold particles at the periphery of the cell. The pseudopodia were intensely stained with gold particles, while they were not detectable in the inner part of the cytoplasm or in any other organelle even under this activated condition. The significance of the specific location of QUIN revealed in the present study and its relation to the release and subsequent actions of QUIN are discussed.
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    Estrogen receptor and progesterone receptor-immunoreactive cells are not co-localized with gonadotropin-releasing hormone in the brain of the female mink (Mustela vison) (1997)
    Springer
    Cell & tissue research 291 (1997), S. 33-41 
    Details
    ISSN: 1432-0878
    Keywords: Key words Estrogen receptor ; Progesterone receptor ; Gonadotropin-releasing hormone ; Preoptic area ; Hypothalamus ; Immunocytochemistry ; Mink (Mustela vison)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The distribution of gonadal steroid (estrogen, progesterone) receptors in the brain of the adult female mink was mapped by immunocytochemistry. Using a monoclonal rat antibody raised against human estrogen receptor (ER), the most dense collections of ER-immunoreactive (IR) cells were found in the preoptic/anterior hypothalamic area, the mediobasal hypothalamus (arcuate and ventromedial nuclei), and the limbic nuclei (amygdala, bed nucleus of the stria terminalis, lateral septum). Immunoreactivity was mainly observed in the cell nucleus and a marked heterogeneity of staining appeared from one region to another. A monoclonal mouse antibody raised against rabbit uterine progesterone receptor (PR) was used to identify the PR-IR cells in the preoptic/anterior hypothalamic area and the mediobasal hypothalamus (arcuate and ventromedial nuclei). This study also focused on the relationship between cells containing sex-steroid receptors and gonadotropin-releasing hormone (GnRH) neurons on the same sections of the mink brain using a sequential double-staining immunocytochemistry procedure. Although preoptic and hypothalamic GnRH neurons were frequently in close proximity to perikarya containing ER or PR, they did not themselves possess receptor immunoreactivity. The present study provides neuroanatomical evidence that GnRH cells are not the major direct targets for gonadal steroids and confirms for the first time in mustelids the results previously obtained in other mammalian species.
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    Pituitary adenylate cyclase activating polypeptide (PACAP) in the gastrointestinal tract of the rat: distribution and effects of capsaicin or denervation (1997)
    Springer
    Cell & tissue research 291 (1997), S. 65-79 
    Details
    ISSN: 1432-0878
    Keywords: Key words Immunochemistry ; Chromatography ; Immunocytochemistry ; PACAP ; VIP ; CGRP ; NOS ; GRP ; Gastointestinal tract ; Capsaicin ; Denervation ; Rat (Sprague Dawley ; Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The expression of pituitary adenylate cyclase activating polypeptide (PACAP) was studied in the gastrointestinal tract (GI-tract) of normal rats using radioimmunoassay, chromatography, immunocytochemistry, and in situ hybridization. PACAP-38, PACAP-27, and PACAP-related peptide were demonstrated in all parts of the GI-tract, PACAP-38 being the predominant form confirmed by chromatography. PACAP-immunoreactive nerve fibers and nerve cell bodies were found in the myenteric ganglia throughout the GI-tract. PACAP-containing nerve cell bodies were also demonstrated in the submucous ganglia of the small and large intestine. The synthesis of PACAP in intrinsic neurons was confirmed by in situ hybridization. Double immunostaining showed that PACAP is present in calcitonin gene-related peptide-containing sensory nerve fibers as well as in vasoactive intestinal polypeptide (VIP)- or VIP/gastrin-releasing peptide (GRP)-containing (intramural) nerve fibers in the upper GI-tract and in anally projecting, intrinsic VIP-and VIP/nitric oxide syntase-containing nerve cell bodies and nerve fibers in the small and large intestine. Neonatal treatment with capsaicin significantly reduced the concentration of PACAP-38 in the esophagus, stomach, and colon. Extrinsic denervation decreased the PACAP-38 concentration in the stomach, while no change was observed in the small intestine. These results indicate that PACAP- immunoreactive nerve fibers in the GI-tract originate from both intrinsic (enteric) and extrinsic (presumably sensory) sources suggesting that PACAP may have diverse gastrointestinal functions.
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    Reversibility of omeprazole-evoked changes in the ultrastructure of ECL cells in the rat stomach (1997)
    Springer
    Cell & tissue research 291 (1997), S. 91-95 
    Details
    ISSN: 1432-0878
    Keywords: Key words ECL cells ; Omeprazole ; Granules/vesicles ; Ultrastructure ; Stomach ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  The ECL cells are histamine- and peptide hormone-producing endocrine cells in the rat oxyntic mucosa. They are rich in secretory vesicles and also contain microvesicles and electron-dense granules. They operate under the control of circulating gastrin. In the present study, we examined the ECL-cell ultrastructure after long term treatment with omeprazole, which is known to induce hypergastrinemia, and after withdrawal of the drug. Rats received omeprazole (400 µmol/kg per day, orally) for 16 days and were killed 1, 5, 20, or 40 days after the last dose of the drug. Oxyntic mucosal specimens were processed for electron microscopy. Electron micrographs of ECL-cell profiles were analyzed planimetrically. The ECL-cell profile area increased promptly in response to omeprazole, the secretory vesicles and granules were reduced in number and volume density, the microvesicles were unchanged in number but reduced in volume density, and vacuoles appeared. Within a week after stopping the omeprazole treatment, the numbers and volume densities of secretory vesicles and microvesicles returned to pre-stimulation values. Also, the vacuoles disappeared promptly. The ECL-cell profile area decreased below the pre-stimulation level within five days after stopping treatment, while, in contrast, the granules increased in number and volume density. Somewhat surprisingly, the cell size and the granule compartment did not return to normal until 40 days after stopping treatment.
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    Allatostatin in hemocytes of the cockroach Diploptera punctata (1997)
    Springer
    Cell & tissue research 290 (1997), S. 119-128 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Allatostatin ; Immunocytochemistry ; In situ hybridization ; Hemocytes ; Inhibition of corpora allata ; Diploptera punctata (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Allatostatins are neuropeptides that inhibit the production, by the corpora allata, of a major insect hormone, juvenile hormone. These peptides are produced by cells of the brain and ganglia as well as by midgut endocrine cells. Transport from these sites may contribute to the allatostatin content in the hemolymph (insect blood). Using a monoclonal antibody against Diploptera punctata allatostatin I (A-P-S-G-A-Q-R-L-Y-G-F-G-L-NH2) and in situ hybridization with a digoxigenin-labeled cRNA probe generated from a portion of the allatostatin gene, it is demonstrated that allatostatin is present in and synthesized by granular hemocytes of D. punctata. About 5% of the hemocytes react with anti-allatostatin antibody and a similar number hybridize with a cRNA probe that detects allatostatin-specific mRNA. Electron micrographs showed that allatostatin-immunoreactive material occurs in membrane-bound, uniformly dense granules that frequently fill fusiform-shaped cells. Allatostatin in cell and plasma fractions of hemolymph quantified by enzyme-linked immunosorbent assay and by bioassay for inhibition of juvenile hormone synthesis in vitro indicated that about equal quantities (0.1–0.2 fmol/μl) are present in cell and plasma fractions. The production of allatostatin by hemocytes suggests that allatostatins may function as regulatory peptides in hemolymph activities in addition to their other known functions.
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  • 96
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    Aquaporin-related proteins in the filter chamber of homopteran insects (1997)
    Springer
    Cell & tissue research 290 (1997), S. 143-151 
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    ISSN: 1432-0878
    Keywords: Key words: Aquaporins ; AQPcic ; Filter chamber ; Homopteran insects ; Immunocytochemistry ; Cicadella viridis ; Euscelidius variegatus ; Scaphoideus titanus (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. In the Homopteran order of insects, the plant xylem feeders exhibit a highly differentiated part of their digestive tract known as the filter chamber. In this tissue, water crosses plasma membranes through a transepithelial osmotic gradient. In previous studies on the filter chamber of Cicadella viridis, we purified and characterized from the plasma membranes a 25 kDa protein that we demonstrated to be an aquaporin (or water channel, member of the major intrinsic protein family, a group of membrane channels for small solutes). We called this protein AQPcic for Cicadella aquaporin. In the present study, we used polyclonal antibody anti-AQPcic in Western blotting and immunocytochemical analysis of the intestinal tract of Cercopis sanguinolenta, Philaenus spumarius, Aphrophora alni (Cercopidae), Euscelidius variegatus, and Scaphoideus titanus (Jassidae). Western blotting experiments revealed that immunologically related AQPcic proteins are found in those species. The molecular weight of these proteins is 15–26 kDa. Immunocytochemical studies on ultrathin filter-chamber sections revealed that the anti-AQPcic antibody systematically labelled the membrane microvilli of epithelial cells. A good correlation thus exists between the physiology of these cells and the presence of aquaporin-related proteins in their membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050916
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  • 97
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    Development of striated rootlets during ciliogenesis in the human oviduct epithelium (1997)
    Springer
    Cell & tissue research 290 (1997), S. 39-42 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Ciliogenesis ; Striated rootlets ; Oviduct ; Ciliated cells ; Ultrastructure ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Striated rootlets in ciliated cells are conical banded structures composed of longitudinally aligned filaments. The formation of striated rootlets during ciliognesis in the human oviduct epithelium was studied by electron microscopy. Primitive rootlets appeared at the proximal side of basal bodies before or at the same time as ciliary budding. After the formation of several striations, the tip of the rootlets extended deeply toward the interior of the cell and became differentiated into two distinct parts, viz., the proximal conical part connected to the basal body and the distal fibrillar part. The periodicity of the striations in the fibrillar part was 68.5±2.95 nm, about 5 nm longer than that of the conical part (63.9±2.25 nm). The dark band in the striation was thicker in the fibrillar part than in the conical part. Since the fibrillar part was not observed in the mature cilium, this part was considered as being either degraded or changed into the conical part during ciliogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050905
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  • 98
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    Immunoreactive excitatory amino acids in the parietal eye of lizards, a comparison with the pineal organ and retina (1997)
    Springer
    Cell & tissue research 287 (1997), S. 275-283 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Parietal eye ; Pineal organ ; Retina ; Glutamate ; Aspartate ; Immunocytochemistry ; Electron microscopy ; Lacerta muralis ; Lacerta agilis ; Lacerta viridis (Lacertilia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The fine structure of the organ and the localization of the excitatory amino acids glutamate and aspartate were studied in the parietal eye of lizards by postembedding immunoelectron microscopy. The parietal eye contains cone photoreceptor cells, secondary neurons, and ependymal and lens cells. The photoreceptors form long inner and outer segments, some of them being paired as ”twin-photoreceptors” by zonulae adherentes. Perikarya of neurons bear sensory cilia (containing 9×2+0 pairs of tubules) extending into the intercellular space. No neurohormonal terminals are present in the parietal eye. A higher immunoreactivity to glutamate than to aspartate is found in the photoreceptors and in the secondary neurons of the parietal eye. Glutamate immunogold labeling is more intense in the axonal processes of photoreceptors and neurons and in most of the nerve fibers of the parietal nerve running to the brain stem. Weak aspartate and glutamate immunoreactivity can be detected in the ependymal and lens cells. A similar distribution of immunoreactive amino acids is found in the photoreceptors, secondary neurons, and ependymal glial elements of the pineal organ, and retina of the lateral eye of the same animals. Immunoreactive glutamate accumulates in the axons of photoreceptors and secondary neurons of the parietal eye suggesting that this excitatory amino acid acts as a synaptic mediator in the neural efferentation of the organ. Thus, the efferent light-conducting pathway of the parietal organ is similar to that of the pineal organ and lateral eye retina. As the Mullerian cells of the retina, the ependymal and lens cells of the parietal eye and the ependymal-glial cells of the pineal organ may play a role in the metabolism and/or elimination of excitatory amino acids released by photoreceptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050752
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  • 99
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    Oxytocin innervation of spinal preganglionic neurons projecting to the superior cervical ganglion in the rat (1997)
    Springer
    Cell & tissue research 287 (1997), S. 481-486 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Oxytocin ; Immunocytochemistry ; Paraventricular nucleus ; Superior cervical ganglion ; Spinal cord ; Sympathetic nervous system ; Retrograde tracing ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The paraventricular nucleus of the hypothalamus is a major integrative nucleus for relaying information from the suprachiasmatic nucleus to the autonomic system. The precise pathway by which this information can influence autonomic functions, such as melatonin synthesis in the pineal gland, is not clear. In the present study, we used a retrograde tracer injected in the superior cervical ganglion to identify spinal preganglionic neurons. One of the main neurotransmitters present in descending projections of the paraventricular nucleus of the hypothalamus, oxytocin, was detected with immunocytochemistry to visualise possible contacts with the neurons located in the intermediolateral column of the spinal cord and projecting to the superior cervical ganglion. Although many appositions could be seen at the light-microscopic level, this abundance could not be confirmed at the electron-microscopic level. The implications of these observations for the overall timing message received by the spinal preganglionic neurons are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050772
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  • 100
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    Coexpression of neuropeptide Y and vasoactive intestinal polypeptide in pelvic plexus neurones innervating the uterus and cervix in the rat (1997)
    Springer
    Cell & tissue research 288 (1997), S. 285-292 
    Details
    ISSN: 1432-0878
    Keywords: Key words: NPY ; VIP ; Pelvic ganglia ; Immunocytochemistry ; In situ hybridization ; Retrograde tracing (Fluoro-Gold) ; Genital tract ; Rat (Sprague Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The present study investigates the distribution and coexpression of neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) in neurones of the accessory ganglion (AG), hypogastric plexus (HP) and paracervical ganglion (PCG), which compose the pelvic plexus in the female rat. Nerve cell bodies immunoreactive for NPY and VIP represent 84% and 46% of the neurone population in the PCG, respectively, while immunoreactivity for each peptide is observed in about 90% of the AG and HP neurones. Adjacent sections immunostained for NPY and VIP, as well as the use of immunocytochemistry combined with in situ hybridization show that 92% of the VIP-containing neurones in the pelvic plexus also contain NPY. In addition, a retrograde tracing study performed in combination with immunocytochemistry demonstrates that pelvic plexus neurones project preferentially to the lower part of the uterus and to the cervix, and that about 95% of these projecting neurones contain VIP. Taken together, our findings indicate that in the female rat, neurones of the pelvic plexus projecting to the lower genital tract mainly coexpress VIP and NPY, and supply nerve fibres to the vascular and nonvascular smooth muscle in the uterocervical region. Since NPY and VIP exert distinct effects according to the target tissue, our results suggest that neurones coexpressing these peptides play important roles in the local regulation of the vascular bed and motor activity of the lower genital tract.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050814
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