ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Ultrastructure  (152)
  • Springer  (152)
  • Springer Science + Business Media
  • 1980-1984  (152)
  • 1983  (74)
  • 1981  (78)
Collection
Keywords
Publisher
  • Springer  (152)
  • Springer Science + Business Media
Years
  • 1980-1984  (152)
Year
  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructure of differentiating preameloblasts from tooth germs of the permanent dentition ofMacaca mulatta andMacaca arctoides (1981)
    Springer
    Calcified tissue international 33 (1981), S. 603-618 
    Details
    ISSN: 1432-0827
    Keywords: Preameloblasts ; Tooth germs ; Monkey ; Enamel ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Cytodifferentiation of inner enamel epithelium and the adjacent connective tissue from the tip of the cervical loop to the initiation of enamel elaboration in twoMacaca species was examined. Ten- to twelve-month-old specimens were fixed by perfusion and the permanent tooth buds were prepared for transmission electron microscopy. At the cervical loop proper, inner enamel epithelium cells have lobed nuclei, a paucity of cytoplasm, and wide extracellular spaces; the basal lamina facing the dental papilla is straight. With increasing distance from the tip of the cervical loop, the following changes occur gradually: (a) preameloblasts elongate from 15 to 45 µm, and their organelles, particularly mitochondria and profiles of rough endoplasmic reticulum, become more numerous; (b) extracellular spaces decrease between preameloblasts starting at the basal (infranuclear) end; (c) the basement membrane becomes convoluted and associated with aperiodic fibers; (d) preodontoblast projections penetrate the aperiodic fibers; (e) collagen fibers subjacent to the basement membrane increase in density, with particularly thick fibers paralleling the aperiodic fibers. These modifications occur within three-fourths of the distance from the tip of the cervical loop to the mineralization front. The condensation of preodontoblasts is followed immediately by predentin synthesis. Concomitantly, the basement membrane breaks down and the aperiodic fibers are engulfed by preameloblasts. Preameloblast projections penetrate junctional predentin, contact mineralized dentin, and enamel synthesis ensues. At this stage the ameloblast is 45 µm long, the nucleus is central or basal, the Golgi apparatus has migrated apically, but the Tomes' process has not yet formed. The results indicate that odontogenesis inMacaca monkeys more closely resembles human odontogenesis than does that in the murine rodents.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02409498
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of adenylate cyclase and cAMP phosphodiesterase in the gastrulating chick embryo (1983)
    Springer
    Development genes and evolution 192 (1983), S. 42-44 
    Details
    ISSN: 1432-041X
    Keywords: Chick embryo ; Gastrulation ; Adenylate cyclase ; cAMP phosphodiesterase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructural localization of adenylate cyclase (E.C. 4.6.1.1.) and cAMP phosphodiesterase (PDE) (E.C. 3.1.4.17.) in the ectoderm of the developmental stage 4 chick embryo was studied. Adenylate cyclase was localized in the lateral surfaces of the ectodermal cells. In the primitive streak cells the enzymatic activity was observed on all the lateral surfaces, whereas in the periphery of the blastoderm the reaction product was localized in the apical parts of the lateral plasma membranes only. cAMP PDE localized in the apical cytoplasm of the ectodermal cells, with highest activity in the globular projections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848768
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Electron microscopical study of self-differentiation potency in the chick embryonic endoderm cultured in vitro (1983)
    Springer
    Development genes and evolution 192 (1983), S. 171-178 
    Details
    ISSN: 1432-041X
    Keywords: Differentiation ; Digestive tract ; Endoderm ; Organ culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The self-differentiation potency of the endoderm of the chick embryo was investigated mainly by transmission electron microscopy. Endodermal fragments isolated from 4- to 6-day stomach or small intestine were cultured in the absence of mesenchyme and were able to differentiate in vitro into organ-specific epithelia. Endodermal fragments isolated from the stomach region differentiated into a pseudo-stratified epithelium with periodic acid Schiff-positive mucous granules in the apical cytoplasm, while those from the small intestinal region differentiated into a simple columnar epithelium with a striated border which was positive in alkaline phosphatase activity. These features are comparable with those of the mucous secretory epithelium of the normal embryonic stomach and the absorptive epithelium of normal embryonic small intestine, respectively. Next, the self-differentiation potencies were investigated of the upper and lower layers of the blastoderms, at stages 1–5 of Hamburger and Hamilton (H. and H.). Both stomach-type and small-intestine-type epithelia developed only when fragments of the lower layer isolated from the blastoderms older than stage 3 of H. and H. were cultured, suggesting that cells possessing the potency to differentiate into the stomach- and small-intestine-type epithelia exist in the definitive endoderm at the beginning of its formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848687
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Ultrastructural events and kinetics of microcyst germination in the myxomycete Didymium iridis (1981)
    Springer
    Archives of microbiology 128 (1981), S. 384-389 
    Details
    ISSN: 1432-072X
    Keywords: Didymium iridis ; Microcyst ; Excystment ; Germination ; Ultrastructure ; Mycetozoa ; Myxomycetes ; Myxamoeba
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microcysts of the myxomycete Didymium iridis were induced to excyst by transfer to 5mM potassium phosphate buffer. After 1 h in suspension, 90% of the microcysts had germinated into myxamoebae distinguishable by phase contrast microscopy and staining with Lugol's iodine. Both pH and osmolarity affected the kinetics of excystment. The rate and extent of excystment were decreased by cycloheximide but remained unaffected by actinomycin D, suggesting a requirement for protein synthesis but not RNA synthesis. Initially, the outer wall layers separated from the inner layer, which gradually expanded and loosened. The protoplast rehydrated and reverted to a vegetative morphology. Excysting cells were characterized by nucleolar inclusions, changes in the nuclear envelope and plasma membrane, appearance of ringed cisternal elements and microbodies in the cytoplasm, and formation of a densely fibrous zone adjacent to the site of emergence. Excysting populations have been classified into characteristic stages: mature, initiated, swollen, and pre-emergent microcysts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00405917
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    The effects of nitrogen limitation on the ultrastructure of the cyanobacterium Agmenellum quadruplicatum (1981)
    Springer
    Archives of microbiology 130 (1981), S. 204-212 
    Details
    ISSN: 1432-072X
    Keywords: Agmenellum quadruplicatum ; Nitrogen starvation ; Ultrastructure ; PATO poststain ; Cyanobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of nitrogen limitation on the ultrastructure of the unicellular cyanobacterium, Agmenellum quadruplicatum, were studied by thin sectioning transmission electron microscopy. Nitrogen became limiting for growth 14–15 h after transfer to nitrogen-limiting medium, but cultures retained full viability for at least 45 h. The c-phycocyanin: chlorophyll a ratio and cellular nitrogen content of the culture dropped rapidly after 14–15 h, as a progressive deterioration of major cell structures took place. Phycobilisomes were degraded first, followed by ribosomes and, then, thylakoid membranes. These structures were virtually depleted from the cells within 26 h. Intracellular polysaccharide accumulated in place of the normal cell structures throughout this period. Nitrogen limitation did not affect polyphosphate bodies, carboxysomes, lipid granules, the cell envelope, or the extra-cellular glycocalyx. All of the ultrastructural changes resulting from nitrogen limitation were reversed upon addition of nitrate to a starved culture. Most cell structures were restored within 3 h, and restoration was complete within 9 h.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00459520
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Arthrobacter P 1, a fast growing versatile methylotroph with amine oxidase as a key enzyme in the metabolism of methylated amines (1981)
    Springer
    Archives of microbiology 129 (1981), S. 72-80 
    Details
    ISSN: 1432-072X
    Keywords: Arthrobacter ; Facultative methylotroph ; Amine oxidase ; Catalase ; RuMP cycle of formaldehyde fixation ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A facultative methylotrophic bacterium was isolated from enrichment cultures containing methylamine as the sole carbon source. It was tentatively identified as an Arthrobacter species. Extracts of cells grown on methylamine or ethylamine contained high levels of amine oxidase (E.C. 1.4.3.) activity. Glucose- or choline-grown cells lacked this enzyme. Oxidation of primary amines by the enzyme resulted in the formation of H2O2; as a consequence high levels of catalase were present in methylamine-and ethylamine-grown cells. The significance of catalase in vivo was demonstrated by addition of 20 mM aminotriazole (a catalase inhibitor) to exponentially growing cells. This completely blocked growth on methylamine whereas growth on glucose was hardly affected. Cytochemical studies showed that methylamine-dependent H2O2 production mainly occurred on invaginations of the cytoplasmic membrane. Assimilation of formaldehyde which is generated during methylamine oxidation was by the FBP variant of the RuMP cycle of formaldehyde fixation. The absence of NAD-dependent formaldehyde and formate dehydrogenases indicated the operation of a non-linear oxidation sequence for formal-dehyde via hexulose phosphate synthase. Enzyme profiles of the organism grown on various substrates suggested that the synthesis of amine oxidase, catalase and the enzymes of the RuMP cycle is not under coordinate control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00417184
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Ultrastructure of tuberculate spores in Streptomyces thermoviolaceus (1983)
    Springer
    Archives of microbiology 134 (1983), S. 295-298 
    Details
    ISSN: 1432-072X
    Keywords: Actinomycetes ; Streptomyces thermoviolaceus ; Sporogenesis ; Spore ornamentation ; Cupular knobs ; Sheath ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sporogenesis of aerial spores in Streptomyces thermoviolaceus corresponded to a common sporulation type in the genus. The sporulation septum was composed of an outer ring-shaped constriction wall and an inner interspace septum arising by the inwards growth of a double annulus. In mature spores the wall was composed of two layers, the outer one was part of the parent hyphal wall and septum material, the inner one was formed de novo. The spore chains were enclosed by the thin breakable sheath containing small rod-like elements. The ornamentation in the form of knobs, which were a characteristic feature of the species originated from the sheath. The knobs were hemispherical particles with an inner electron dense core and an outer electron transparent shell. The term “cupular knobs” was suggested for this type of tuberculate ornamentation. Frequently, the knobs became detached from the surface in which case the inner core separated easily from the shell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00407805
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Chroococcus S24 and Chroococcus N41 (cyanobacteria): morphological, biochemical and genetic characterization and effects of water stress on ultrastructure (1983)
    Springer
    Archives of microbiology 135 (1983), S. 81-90 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Nitrogen fixation ; Water stress ; Taxonomy ; DNA ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two strains of desiccation-tolerant coccoid cyanobacteria, Chroococcus S24, a marine form, and Chroococcus N41, a cryptoendolith isolated from a hot-desert rock, have been characterized. The mol % DNA base compositions of the strains are 47.1 and 48.9% respectively. Plasmid DNA was not detected in either strain. The pigment contents and nutritional characteristics of the strains are identical. Both lack phycoerythrinoid pigments and, in culture, behave as slow-growing halotolerant marine forms with elevated requirements for Na+, Cl−, Mg2+ and Ca2+. Sucrose was the only carbon source of those tested that supported photoheterotrophic growth. Each strain synthesizes nitrogenase under anaerobic conditions but not in air. Morphologically the two strains are indistinguishable. They are considered to be independent isolates of the same cyanobacterial species. Chroococcus N41 was studied in detail with the electron microscope. When brought to equilibrium at matric water potentials of-168 MPa and lower (to-673 MPa=c0.12a w) the protoplast shrinks, but the cells maintain the same size and diameter as those at-2,156 kPa (MN medium; control); the sheath expands and remains attached to the cell wall outer membrane by fibrils. The cell wall, cell membrane, thylakoid membranes, cyanophycin granules and carboxysomes appeared intact in desiccated cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408014
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The pineal gland of nocturnal mammals (1981)
    Springer
    Cell & tissue research 216 (1981), S. 253-271 
    Details
    ISSN: 1432-0878
    Keywords: Pinealocytes ; Cell populations ; Bat ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the pineal gland of the pipistrelle bat two different populations of pinealocytes and glial cells were observed electron microscopically. The pinealocytes of populations I and II differ in their content of metabolically active cell organelles. In the pinealocytes of population I, granular vesicles originating from the Golgi apparatus were found in the perikaryon and especially in the endings of the pinealocyte processes. Granular vesicles appeared to be more numerous in hibernating nulliparous females. The pinealocytes of population II are characterized by the presence of small cytoplasmic vacuoles, probably originating from cisternae of the granular endoplasmic reticulum and containing flocculent material of moderate electron density. The classification of the pinealocytes belonging to population II is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233619
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    The fine structure of the compound eye of the African armyworm moth, Spodoptera exempta walk. (Lepidoptera, Noctuidae) (1981)
    Springer
    Cell & tissue research 216 (1981), S. 333-347 
    Details
    ISSN: 1432-0878
    Keywords: Insect eye ; Retina ; Ultrastructure ; Moth ; Spodoptera exempta
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of the compound eye of the noctuid moth Spodoptera exempta was investigated by electron microscopy. This eucone superposition eye is composed of about 8000 ommatidia. Each ommatidium is surrounded by six secondary pigment cells showing pigment movement according to the state of adaptation. It contains four crystalline cone cells forming together a crystalline cone and tract, two primary pigment cells, which encompass the crystalline cone, and usually eight retinula cells. On the basis of their rhabdomeric structure, three types of retinula cells can be distinguished. According to the structure of the rhabdom, two types of ommatidia are found in different regions of the eye. The rhabdom of the lobed type, providing more than 80% of ommatidia, is composed of V-shaped rhabdomeres with fanwise arranged microvilli. The rhabdom of the square type, found in a small area in the dorsal region of the eye, consists of triangular rhabdomeres with parallel microvilli. The functional significance of this difference is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233623
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Ultrastructure of catecholamine-containing axons in the intestine of the domestic fowl (1983)
    Springer
    Cell & tissue research 234 (1983), S. 411-425 
    Details
    ISSN: 1432-0878
    Keywords: Intestines (chicken) ; Innervation ; Catecholamines ; Adrenergic fibres ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Axons in the duodenum, ileum and rectum of the domestic fowl were identified as catecholamine-containing (CA) on the basis of positive reactivity following chromaffin fixation for electron microscopy. CA-axons in association with blood vessels in all regions of the intestine and in non-vascular sites in the small intestine had a ‘ typical’ adrenergic appearance, in that they contained many small granular vesicles (SGV) and variable numbers of large granular vesicles (LGV). In the rectum the non-vascular CA-axon profiles were atypical, in that there were many elongated LGV and few SGV, and the chromaffin reactivity was weak. The nerve profiles in the rectum were dramatically reduced following 6-hydroxydopamine and reserpine treatment and were absent in rectum cultured in the absence of extrinsic ganglia. It was concluded that the profiles, in spite of their low chromaffin reactivity, truely represent CA-axons. The possibility was raised that the atypical morphology and reduced chromaffin reactivity is due to the presence of adrenaline.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213778
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Ultrastructural identification of corticotropes of the fetal rat (1983)
    Springer
    Cell & tissue research 234 (1983), S. 427-437 
    Details
    ISSN: 1432-0878
    Keywords: Corticotropes ; Rat fetus ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Corticotropes of rat fetuses aged 16, 18 and 21 days were localized by the indirect antibody-enzyme method on semithin sections of the pituitary. The development of the ultrastructure of these cells was observed on consecutive ultrathin sections. In comparison with previous data our present results show that identification of a fetal cell type cannot be based entirely on morphological criteria. The structural peculiarities of corticotropes obtained from studies in vivo are compared with those observed in cells maintained in vitro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213779
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Cyclophosphamide-induced changes in rodent odontogenesis (1983)
    Springer
    Cell & tissue research 234 (1983), S. 679-689 
    Details
    ISSN: 1432-0878
    Keywords: Odontogenesis ; Rats ; Cyclophosphamide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclophosphamide-induced changes in rodent odontogenesis were investigated by light and electron microscopy in four-day-old Sprague Dawley rats given one injection of 40 mg/kg of body weight of cyclophosphamide and killed at intervals of one hour, one day, one week and two weeks. Incisor and molar teeth were dissected from the animals, fixed in 2.0% glutaraldehyde in 0.1 M sodium cacodylate with 3.4% sucrose, and subsequently some were incubated for alkaline phosphatase reaction, and embedded in Spurr's medium for sectioning at light- and electron-microscopic levels. From three days a cell-sparse zone was created in the pulp in the growing end of the tooth and progressive cellular changes were observed which became more severe in the one-week and two-week specimens. Subodontoblast and adjacent pulpal cells were the most affected showing nuclear changes, damage to, or loss of, organelles, and inclusion bodies. Odontogenic epithelium was less affected and odontoblasts appeared to be unaffected by the drug. A new irregular matrix was laid down in the defect area and seemed to be the product of depolarized odontoblasts. This new matrix showed alkaline phosphatase activity, as did the cells embedded in it, and later it became mineralized. It is speculated that the polarity of odontoblasts might be maintained by an intact subodontoblastic layer; when this is lost the odontoblasts become depolarized and capable of secreting matrix from both ends.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218659
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Rhythmic contractions of the ampullar epidermis during metamorphosis of the ascidian Molgula occidentalis (1981)
    Springer
    Cell & tissue research 216 (1981), S. 293-312 
    Details
    ISSN: 1432-0878
    Keywords: Ascidians ; Metamorphosis ; Attachment organs ; Ultrastructure ; Rhythmic contractions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ampullae of Molgula occidentalis are hollow, tubular extensions of the epidermis. They are ensheathed by a secreted tunic. When they grow out shortly after settlement, the ampullae spread the tunic over the substratum to form a firm attachment for the sessile juvenile. A simple squamous epithelium forms the thin ampullar walls. A glandular, simple columnar epithelium forms the distal tip of each ampulla. The glandular cells probably secrete the adhesive that attaches the tunic to the substratum. Repetitive, peristaltic contractions pass from the base to the distal end of each ampulla. Microsurgery, time-lapse cinemicrography and TEM have been used to analyze this phenomenon. The contractions are mediated by a layer of 4–8 nm microfilaments in the base of the ampullar epithelium. Each juvenile has 7–9 ampullae which contract at different frequencies. Isolated ampullae continue to contract normally for several days. Thus each ampulla has an intrinsic rhythm. Microsurgical experiments suggest that there is no specific region within an ampulla with unique pacemaker properties. It is proposed that communication via gap junctions allows the coordination of ampullar cells into a well organized peristaltic wave.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233621
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Isolation of metabolically active endothelial cells in high yield from bovine cavernous bodies (1983)
    Springer
    Cell & tissue research 232 (1983), S. 579-591 
    Details
    ISSN: 1432-0878
    Keywords: Cavernous bodies ; Endothelial cells ; Respiratory activity ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Work on endothelial cells has been limited by the availability of procedures for obtaining such cells in quantities adequate for direct in vitro analysis. The present paper describes a method for the isolation of endothelial cells from bovine cavernous bodies. A number of cells ranging from 2.5 to 4 × 108 per animal has been obtained. The cells were identified as follows 1) presence of the “Weibel and Palade” bodies in the isolated cells, 2) “cobblestone” appearance of cell cultures, and 3) presence of factor VIII, as demonstrated by immunofluorescence assays. The cell viability at the end of the purification procedure was tested 1) by dye-exclusion tests and 2) by metabolic assays. Features of this preparation are 1) the very high yield of viable endothelial cells, 2) the absence of contamination by fibroblasts and smooth muscle cells and a very low contamination by erythrocytes and 3) the fine dispersion of the isolated cells. These properties allow functional and subcellular fractionation studies on freshly isolated endothelial cells of microvascular origin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216430
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Ultrastructural morphometry of the myocardium of Thunnus alalunga (1983)
    Springer
    Cell & tissue research 233 (1983), S. 427-438 
    Details
    ISSN: 1432-0878
    Keywords: Myocardium ; Thunnus alalunga ; Ultrastructure ; Mitochondria ; Myofibrils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The common ventricle in the heart of the Thunnus alalunga was studied. The ventricular myocardium consists of an outer compact layer and a thick inner spongy layer. The compact layer has slightly larger cells (4–6 μm diameter) than the spongy layer (2.5–5 μm diameter). Ultrastructurally the myocardium displays normal arrangements of myofibrils and mitochondria. The sarcoplasmic reticulum is poorly developed. The intercalated discs are simple with the fascia adherens being the most frequent junctional type observed; occasionally a desmosome was seen. Nexus type junctions are present but are unassociated with the intercalated discs. There are no t-tubules evident but the plasmalemma exhibits numerous caveolae which rarely form couplings with the sarcoplasmic reticulum. A morphometric analysis of the volume percent of mitochondria and myofibrils showed that the myocardial cells in the spongy layer of the heart have a significantly greater volume percentage of mitochondria than the compact layer. No significant differences were found between myocardial regions when the volume percentages of myofibrils were compared. The physiological studies revealed that the albacore tuna has heart rates (120 bpm) and ventricular blood pressures (100 mmHg) that are among the highest reported for fish.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238308
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Ultrastructural and immunohistochemical studies of rat epididymis (1983)
    Springer
    Cell & tissue research 233 (1983), S. 523-537 
    Details
    ISSN: 1432-0878
    Keywords: Epididymis (rat) ; Myosin ; Actin ; Fibronectin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anatomical distribution of smooth muscle actin, myosin, fibronectin and basement membrane has been investigated immunohistochemically, using the indirect immunofluorescence technique, in the rat epididymis. The findings were correlated with the ultrastructural organization of the organ. Actin was found to be distributed in the stereociliary region of the epithelial principal cells and in the terminal web region. Actin was also visible along the base of the epithelium. Myosin was detected in the terminal web and in the terminal bar regions of the epithelium. The contractile cells showed a strong stain for both proteins. Basement membrane immunoreactivity was distributed along the epithelial basement membrane and around the contractile cells of the wall. In the cauda, between the epithelium and the contractile cell layers, the lamina propria, containing blood vessels and a thin layer of cells, was negative for all antigens investigated. Fibronectin showed a granular distribution around the contractile cells, mainly in the cauda. The ultrastructural study showed only thin (5–6 nm in diameter) filaments in the stereocilia and terminal web region. Thin filaments were also visible in the cytoplasm of the basal cells, thus suggesting a contractile function of this cell type. The heterogeneous appearance of the contractile cells of the wall seemed to support the different contractile pattern of the epididymal regions: caput, corpus and cauda. The cells present in the lamina propria showed cytoplasmic vesicles with dark granules resembling the “A” cell granules of the endocrine pancreas and gut mucosa cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00212222
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    The structure and function of the nematocysts of Chironex fleckeri Southcott, 1956 (1983)
    Springer
    Cell & tissue research 233 (1983), S. 563-577 
    Details
    ISSN: 1432-0878
    Keywords: Nematocysts ; Structure ; Ultrastructure ; Function ; Cubozoa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microbasic p-mastigophores, euryteles of two size groups, holotrichous isorhizas and atrichous isorhizas, comprise the cnidom of Chironex fleckeri, a cubozoan that has been responsible for several human fatalities. In its undischarged state each microbasic mastigophore of C. fleckeri consists of a capsule containing matrix and an inverted tube possessing a smooth-walled butt which is loosely coiled helically and which narrows to form a thread that is tightly coiled helically and markedly pleated. Both butt and thread carry three helices of spines and contain a granular matrix. During discharge, the proximal butt spines form initially a piercing stylet. Granular material from the butt and thread is released prior to the release of capsular material. Each eurytele possesses a tube with a butt composed of three bulbs, the middle bulb bearing long spines. Each holotrichous isorhiza possesses a coiled tube bearing small spines along its length. Each atrichous isorhiza exhibits a tube that is devoid of spines and loosely folded in the undischarged condition. The probable role of each type of nematocyst is inferred from its structure and features that enable the ready separation of the nematocysts of C. fleckeri from those of scyphozoan jellyfish are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00212225
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Ciliary epithelia of the mammalian eye in cultured explants (1983)
    Springer
    Cell & tissue research 233 (1983), S. 629-638 
    Details
    ISSN: 1432-0878
    Keywords: Ciliary process ; Cultured explant ; Epithelial cells ; Ultrastructure ; Bovine and rabbit eyes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characteristics of ciliary epithelium from bovine, pigmented rabbit, and fetal albino rabbit were studied in cultured explants. The tips of ciliary processes were cultured in plastic dishes with Dulbecco Modified Eagle Medium (DMEM) containing 5% fetal bovine serum. More than half of the expiants adhered to the plastic culture dish, and epithelial cells spread as monolayers within a few days. Initially the explant contains two layers, the outer (nonpigmented cells) and the inner (pigmented cells). Later the explant exhibits three layers: 1) outermost lightly pigmented flattened cells, 2) an outer layer of nonpigmented cells, and 3) an inner layer of densely pigmented cuboidal cells. The cells of the outermost layer are continuous with the cells of the inner layer. A narrow space lies between the outermost layer and the outer layer. The columnar cells in the outer layer contain well developed organelles but no pigment granules; they possess a basement membrane, lateral interdigitations, and junctional complexes near their apices. Numerous focal junctions and some ciliary channel-like structures were detected between the columnar cells of the outer layer and the cuboidal cells of the inner layer. The cuboidal cells of the inner layer are filled with pigment granules. These observations suggest that the columnar cells of the outer layer are nonpigmented epithelium, the cuboidal cells of the inner layer are pigmented epithelium, and the flatened cells in the outermost layer are derived from pigmented epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00212230
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Ultrastructural observations on the formation of follicles in the human fetal thyroid (1983)
    Springer
    Cell & tissue research 233 (1983), S. 693-698 
    Details
    ISSN: 1432-0878
    Keywords: Thyroid gland ; Human fetus ; Follicles ; Ultrastructure ; Differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thyroid glands from 40 human fetuses ranging from 30 to 175 mm in length were examined by electron microscopy. At the 30 mm stage, the cells are arranged in cords or clusters and contain numerous free ribosomes. The rough-surfaced endoplasmic reticulum (RER) is poorly developed and the Golgi complex consists of saccules, smooth and coated vesicles. Mitochondria, microfilaments, glycogen particles, occasional lysosome-like structures, and single cilia are observed. At sites of incipient follicle formation, intercellular clefts containing interdigitating microvilli, delimited by junctional complexes, are evident. In addition, the apical region of some cells contains vacuoles. At the 50-mm stage, intercellular clefts are more apparent, some of them organized into small follicles through the enlargement of the lumen, the incorporation of additional cells, and the formation of a basal lamina. With increasing gestational age, more follicles are established. The lumina vary from round to clover-leaf shaped and have an electron-dense content. Cisternae of RER are dilated and contain flocculent material. The Golgi complex is more extensive, and lysosome-like structures are more numerous. By the 100-mm stage, the follicular cells appear morphologically well differentiated. The results demonstrate an extracellular origin of the follicular lumen in the human fetal thyroid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00212236
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Ultrastructural immunocytochemical localization of fibronectin in the developing rat lung (1983)
    Springer
    Cell & tissue research 234 (1983), S. 165-177 
    Details
    ISSN: 1432-0878
    Keywords: Fibronectin ; Lung ; Development ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In a previous study changes in the macrodistribution of fibronectin during rat-lung development were examined. Using the peroxidase-antiperoxidase immunocytochemical technique, we have demonstrated the presence of fibronectin in embryonic, neonatal, and adult rat lung at the ultrastructural level. In the embryo, fibronectin is found both in an intra-and extracellular association with isolated pneumoblasts, and in a periodic distribution along the basal lamina. The neonate displays fibronectin in an intracellular association with early type-I cells and on their basal and luminal surfaces, but not in association with type-II cells. Neonatal basal lamina is diffusely labeled by anti-fibronectin antiserum. Fibronectin in adult tissue is found both intracellularly and on the basal and luminal surfaces of type-I cells but not in type-II cells. The basal lamina and interstitial connective tissue are slightly or non-reactive. These observations confirm and extend our initial suggestion that fibronectin is involved in rat-lung development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217410
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Electron microscopy of extracellular materials during the development of a sea star, Patiria miniata (Echinodermata: Asteroidea) (1983)
    Springer
    Cell & tissue research 234 (1983), S. 193-200 
    Details
    ISSN: 1432-0878
    Keywords: Sea star ; Development ; Cuticle ; Extracellular materials ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of conspicuous extracellular materials during the life history of a sea star (Patiria miniata) is described. The outer surface of the developing sea star is covered by two morphologically different cuticles that appear sequentially during ontogeny. The primary cuticle, which is about 120 nm thick and two-layered, is present from mid-blastula through the end of the larval stage. The secondary cuticle, which is about 1 μm thick and three-layered, first appears on the epidermis of the rudiment region of the larva and, after metamorphosis, covers the entire epidermis of the juvenile and adult stages. During ontogeny, there are only two conspicuous gut cuticles: the first lines the newly invaginated archenteron at the start of the gastrula stage, and the second lines the esophagus during the larval stage. A blastocoelic basal lamina first appears at mid-blastula and persists as subectodermal and subendodermal basal laminae. Ruthenium red-positive granules are detectable between the lateral surfaces of adjacent ectodermal cells during part of the gastrula stage; this transient intercellular material may possibly aid in lateral adhesion between cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217412
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Secretory granules of B-cells in the synovial membrane (1981)
    Springer
    Cell & tissue research 216 (1981), S. 131-141 
    Details
    ISSN: 1432-0878
    Keywords: Synovial membrane ; Secretory granules ; Ultrastructure ; Cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural and cytochemical studies have been made on secretory granules of B-cells (fibroblast-like cells) in the knee-joint synovium. The secretory granules were membrane-bounded spherical or slightly elongated bodies, 150 to 350 nm (average 230 nm) in diameter and had a homogenous matrix with several cores. These granules were found in B-cells of all animal species examined; they were numerous in mice and rats, and few in guinea pigs, rabbits and man. Ultrastructural and cytochemical examinations revealed that the Golgi apparatus was involved in the formation of the secretory granules. Unlike lysosomes, they showed no acid phosphatase activity. The granule matrix was positively stained by Thiéiy's periodic acid-thiocarbohydrazidesilver proteinate technique, and the cores were digested by protease. These findings suggest that the granule matrix contains mucopolysaccharide(s) and/or glycoprotein(s) and the core material is largely proteinaceous in nature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234549
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Effects of norepinephrine and dibutyryl adenosine 3′, 5′-cyclic monophosphate on the ultrastructure of pineal cells in monolayer culture (1981)
    Springer
    Cell & tissue research 216 (1981), S. 181-191 
    Details
    ISSN: 1432-0878
    Keywords: Pineal gland ; Monolayer culture ; N-acetyl transferase ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To determine how neural influences control the function of the pineal gland, morphological and biochemical relationships after pharmacological treatment have been studied in rat pineal cells in monolayer cultures. Norepinephrine (NE) and dibutyryl cyclic 3′,5′-adenosine monophosphate (dBcAMP) treatment of cells that had been in culture for 5 and 21 days produced a stimulation in the enzyme activity of serotonin N-acetyl transferase, an enzyme important in indole synthesis. NE and dBcAMP also produced morphological changes which were dependent on the time of cells in culture. When 5 day-cultures were treated with NE and dBcAMP, light and dark cells were noted and endoplasmic reticulum increased and became more organized. Only dBcAMP treatment at 5 days produced an increase in dense granules and an elongation of cytoplasmic processes. Treatment of 21 day-cultures with dBcAMP also produced an increase in cytoplasmic processes while treatment with NE produced an increase in the synaptic ribbons and clear vesicles within the processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00234553
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Role of estrogen and androgen in maintaining the preovulatory follicle (1981)
    Springer
    Cell & tissue research 216 (1981), S. 615-624 
    Details
    ISSN: 1432-0878
    Keywords: Rat ; Preovulatory follicle ; Ultrastructure ; Estrogen ; Androgen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of Nitromifene citrate (CI 628), an antiestrogen, and Flutamide, an antiandrogen, on the ultrastructure and viability of the preovulatory follicle and granulosa cells were examined both in vivo and in vitro. In vivo administration of either antihormone induced degeneration within the granulosa cells. In some of the affected granulosa cells, the nuclear material was condensed while the cytoplasm and associated organelles were unaltered. In others, the density of the cytoplasm was reduced, the smooth endoplasmic reticulum was dilated but the nucleus remained unaltered. In vitro, either antihormone reduced granulosa-cell viability but the granulosa cells were twenty times more sensitive to CI 628 than to Flutamide. In addition, exposure to CI 628 induced nuclear condensation without affecting the cytoplasm, while Flutamide induced the deterioration of the cytoplasm without altering the nucleus. These observations suggest that: (1) both estrogen and androgens control the viability of the granulosa cells and thereby the follicle, (2) the action of estrogen and androgen is mediated through receptors within the granulosa cells since these antihormones prevent the nuclear uptake of their respective hormone, (3) the granulosa cells of preovulatory follicles appear to be more dependent on estrogen than on androgen, and (4) each steroid appears to have a specific role in maintaining the granulosa cell; estrogens control the integrity of the nucleus while androgens preserve the cytoplasmic organization of the granulosa cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238656
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    The morphology of the horseshoe crab (Limulus polyphemus) visual system (1981)
    Springer
    Cell & tissue research 216 (1981), S. 655-659 
    Details
    ISSN: 1432-0878
    Keywords: Eye ; Neuroeffector junction ; Octopamine ; Circadian rhythm ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Efferent fibers to the compound eye of the horseshoe crab, Limulus polyphemus, not only innervate the various pigment cells, but also invade the eccentric cell dendrite and the retinula cells. This finding provides a structural basis for the coupling of circadian rhythm between the efferents and the receptor cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238660
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Electron-microscopic studies on reaggregate cultures of vascular smooth muscle cells from normotensive and spontaneously hypertensive rats (1981)
    Springer
    Cell & tissue research 217 (1981), S. 225-243 
    Details
    ISSN: 1432-0878
    Keywords: Vascular smooth muscle ; Spontaneously hypertensive rat ; Reaggregate cultures ; Ultrastructure ; Collagen synthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Vascular smooth muscle cells were taken from the aortae of the WKY (normotensive) and SHR (spontaneously hypertensive) strains of rat by enzymatic dispersion and put into reaggregate culture. Initially the cells became individual spheroids having average diameters of 10 μm and surfaces that were either rough or smooth. The cells were far more complex than they appeared on their surfaces; after one day in culture, there was considerable internal variation in these cells. All the cells, whether WKY or SHR, lost the bulk of their cytoplasmic contents (including myofilaments, many mitochondria, and vesicular structures) in the early stages of culture and eventually became flattened. After 14 days in culture, these modified cells collected to form reaggregates that were commonly roughly spherical and several hundred μm in diameter. These reaggregates consisted of peripheral regions made up of several layers of flattened cells overlying cores formed by glia-like networks of cells similar in cytological appearance to the cells at the periphery. The meshes formed in this way contained cellular debris derived from dead cells or extrusion of cellular contents. It appears that SHR cells are quicker to form reaggregates than are WKY cells. Yet the SHR cells retained a rounded conformation after five days, whereas the WKY cells were more flattened and formed a more discrete aggregate at this stage of culture. However, by the fourteenth day of culture, differences between the two cell strains were not so pronounced, as far as could be judged by observations made with scanning and transmission electron microscopy. Both WKY and SHR cells at 14 days appeared highly secretory, possessing large Golgi systems as well as numerous ER cisternae and mitochondria. SHR cells produced greater amounts of connective tissue at all stages of culture than did WKY cells, indicating that a similar difference may contribute to the hypertension which develops naturally in situ in SHR animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233577
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Ultrastructural study of electrophysiologically identified neurones in the paraventricular nucleus of the rat (1981)
    Springer
    Cell & tissue research 216 (1981), S. 503-512 
    Details
    ISSN: 1432-0878
    Keywords: Paraventricular neurones ; Alcian-blue labelling ; Ultrastructure ; Electrophysiology ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characterization of electrophysiologically identified neurones of the rat paraventricular hypothalamic nucleus was performed with extracellular labelling technique. The extracellularly recorded neurones are labelled with an electrophoretic deposit of alcian blue contained in the recording micropipette. The neurone thus labelled takes on a dark and shrunken appearance which enables its detection among neighbouring cells without, however, concealing its main morphological characteristics. 1) Spontaneously firing neurones, invaded by an antidromic action potential elicited by electrical stimulation of the neurohypophysis, were identified as magnocellular cells containing dense-cored vesicles of 200–250 nm in diameter. Dense-cored vesicles were not found in the antidromically activated neurones devoid of spontaneous activity. 2) Trans-synaptically activated neurones in the PVN or in its dorso-lateral edge were small cells devoid of dense secretory vesicles. 3) PV neurones in which neurohypophysial stimulation evoked no response, contained small, dense vesicles (100 nm in diameter) comparable with those found in parvocellular peptidergic neurones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238647
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Pore canals in the cornea of a functionally specialized area of the honey bee's compound eye (1981)
    Springer
    Cell & tissue research 216 (1981), S. 491-501 
    Details
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Cornea ; Compound eye ; Honey bee (Apis mellifera)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the cornea in an anatomically and functionally specialized part of the honey bee's compound eye (dorsal rim area) was examined by light microscopy, transmission electron and scanning electron microscopy. Under incident illumination the cornea appears grey and cloudy, leaving only the centers of the corneal lenses clear. This is due to numerous pore canals that penetrate the cornea from the inside, ending a few μm below the outer surface. They consist of (1) a small cylindrical cellular evagination of a pigment cell (proximal), and (2) a rugged-walled, pinetree-shaped extracellular part (distal). The functional significance of these pore canals is discussed. It is concluded that their light scattering properties cause the wide visual fields of the photoreceptor cells measured electrophysiologically in the dorsal rim area, and that this is related to the way this eye region detects polarization in skylight.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238646
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    The sensillum capitulum, an antennal hygro- and thermoreceptive sensillum of the cockroach, Periplaneta americana L. (1981)
    Springer
    Cell & tissue research 216 (1981), S. 525-543 
    Details
    ISSN: 1432-0878
    Keywords: Hygroreceptor ; Thermoreceptor ; Sensillum capitulum ; Cockroach ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sensillum capitulum, a hygro- and thermoreceptive sensillum of the cockroach Periplaneta americana L. is comprised of four receptor cells, one glial cell, two gland cells and four enveloping cells. Each receptor cell sends a single axon to the CNS, and has a single dendrite which extends distally. The perikarya of three receptor cells are enclosed by one of the enveloping cells (number one) and the fourth by a gland cell. The dendrites of all four receptor cells are enclosed by the same enveloping cell. The dendrites contain rootlets and many microtubules. The sensory cilia arise at the end of the dendrites at the level of the inner cavity, expand from the connecting cilium in a manner similar to those of the amphinematic scolopidia, and have numerous microtubules. The 1st enveloping cell contains scolopale rod-like structures. The sensory cilia are surrounded distally by a cuticular sheath formed within the 1st enveloping cell. One of the sensory cilia disappears distally, and the remaining ones enter the sensillum cone. Of these, one branches and the other two do not. The distal ends of the unbranched cilia are differentiated into tubular structures. The sensillum cone is comprised of an inner stem and a guard wall, neither of which is perforated. The outer cavity is enclosed by the 2nd, 3rd, and 4th enveloping cells, and distally in the antenna is closely apposed to the cuticular wall. This cavity contains lipid deposits. These structural features are discussed with regard to the mechanism of hygroreception in P. americana.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238649
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Stereological studies on the small intestinal epithelium of the rat (1981)
    Springer
    Cell & tissue research 217 (1981), S. 11-21 
    Details
    ISSN: 1432-0878
    Keywords: Intestinal mucosa ; Small intestinal epithelium ; Ultrastructure ; Duodenum ; Jejunum ; Stereology ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Quantitative macroscopic, light-microscopic and electron-microscopic studies were performed on the small intestine of fasted and non-fasted adult, male Sprague-Dawley rats. In non-fasted rats the small intestine was longer than in fasted rats. Due to the presence of villi the surface area in the duodenum and the jejunum was enlarged about six times. The microvilli on the villous crests caused a surface enlargement by 13 times in the duodenum (value corrected for overestimation due to section thickness), and 19 times in the jejunum of the fasted rats. At the base of the villi these values were about 50% lower. It was calculated that, in the fasted rats, the total enlargement of the luminal surface area — due to villi and microvilli — was 63 times in the duodenum and 81 times in the jejunum (corrected for section thickness). Differences between the villous crest epithelium and the villous base epithelium were also found with regard to the mean cell height, and the volume densities of the absorptive cell nuclei, the mitochondria, and the paracellular channels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233821
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Changes in plastid ultrastructure during iron nutrition-mediated chloroplast development (1983)
    Springer
    Protoplasma 114 (1983), S. 85-92 
    Details
    ISSN: 1615-6102
    Keywords: Chloroplasts ; Iron stress ; Sugar beet ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When grown in iron-free media, the youngest leaves of healthy green sugar beet plants became completely yellow after 6 to 8 days. This chlorosis was quickly reversed by resupplying iron. A study of the ultrastructure of the iron -stressed leaves revealed apparently normal subcellular organization except for the plastids which were small and undeveloped, contained a rudimentary, disorganized grana-fretwork and clusters of vesicles in the periphery. Twelve to 16 hours after resupply of iron, aggregates of phytoferritin were observed in the stroma, and the granal fretwork underwent further development. There was an increased orientation of the membranes along the long axis of the plastids and an increase in the length of the individual grana stacks. By 48 hours, leaf chlorophyll content was about 40% of the control. At the ultrastructural level, parallel alignment of membrane orientation was complete and the grana stacks began to increase in the number of thylakoids per stack.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279871
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Nucleolus-associated bodies (karyosomes) in dividing and differentiating plant cells (1983)
    Springer
    Protoplasma 115 (1983), S. 1-10 
    Details
    ISSN: 1615-6102
    Keywords: Brassica napus ; Nucleolus ; Pisum sativum ; Ultrastructure ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The karyosome is a spherical body up to 1 μm in diameter that lies on the nucleolus of certain plant species, particularly those with a relatively low nuclear DNA content and an areticulate nuclear structure. It can be seen in the light microscope after impregnation with silver; in the electron microscope its structure consists of fibrillo-granular material. Nucleoli of cells in root apices may bear 0, 1, or 2 karyosomes. The frequency with which these numbers of karyosomes are observed depends on the location of the cells within the apex. In roots ofPisum sativum andZea mays the nucleoli of both slowly-dividing and young differentiating cells bear karyosomes more frequently than the nucleoli of rapidly-dividing cells. The karyosome seems to adopt a preferred location on the nucleolus, lying most frequently on the nucleolar surfaces directed towards the apex or base of the root. The origin and functional significance of the karyosome are discussed. Morphological evidence suggests that it may be material that formerly was part of a fibrillar centre.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01293574
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Stomatal pore and cuticle formation inFunaria (1983)
    Springer
    Protoplasma 116 (1983), S. 1-13 
    Details
    ISSN: 1615-6102
    Keywords: Cuticle ; Peristomatal transpiration ; Stomata ; Ultrastructure ; Funaria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cuticle and pore development in the guard cells ofFunaria were investigated with the electron microscope. Pore cuticle formation is simultaneous with the creation of the pore itself. The morphology of the pore cuticle is unlike that of any cuticle described in the literature. It has many lamellae which are penetrated by electron dense fibrils. Three different cuticular morphologies exist from the pore to the subsidiary cell walls. The cuticles on the pore and outer walls contain fibrils that sometimes reach to the surface. The subsidiary cell cuticle lacks fibrils altogether. It is hypothesized that (1) cuticularization of the middle lamella contributes to ventral wall separation and (2) differences in extent of cuticular fibrils are related to greater water loss from stomata than from subsidiary cells (peristomatal transpiration).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01294225
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Microtubule organization and morphogenesis in young spores of the mossTetraphis pellucida Hedw (1983)
    Springer
    Protoplasma 116 (1983), S. 115-124 
    Details
    ISSN: 1615-6102
    Keywords: Microtubules ; Moss ; MTOC ; Sporogenesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Microtubule systems appear sequentially at the distal and proximal poles of tetrad members during mid-sporogenesis in the mossTetraphis pellucida Hedw. The distal microtubule system emanates from a microtubule organizing center (MTOC) located between the single plastid and the nucleus. The distal MTOC and associated microtubules, which appear immediately after cytokinesis, are ephemeral and do not appear to be associated with the deposition of exine occuring at the same time. The proximal microtubule system, which appears slightly later than the distal system, is a more stable component of mid-sporogenesis. The proximal MTOC is an irregularly lobed, patelliform aggregation of electron-dense granules located beneath the plasma membrane at the proximal spore pole. Several bundles of microtubules radiate from the proximal MTOC and traverse the cell, enclosing the nucleus in an cone of microtubules. The proximal microtubule system is thought to function in aperture development and organelle migration. The relatively large nucleus migrates a short distance in the small spore early in the tetrad stage and maintains its acentric position at the proximal pole throughout later stages of sporogenesis. The plastid migrates later in the tetrad stage from its meiotic position parallel to the distal surface to a position perpendicular to the distal surface with one tip in close proximity to the proximal MTOC. The proximal microtubule system reaches its maximum development by the end of the tetrad stage and all micrographic evidence of it is lost in the maturation stages of late sporogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279828
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Morphogenesis of coremia and rhizomorphs in the AscomyceteSphaerostilbe repens (1983)
    Springer
    Protoplasma 116 (1983), S. 99-114 
    Details
    ISSN: 1615-6102
    Keywords: Sphaerostilbe repens ; Ultrastructure ; Differentiation ; Coremia ; Rhizomorphs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The differentiating stages of coremia and rhizomorphs inSphaerostilbe repens were studied by transmission electron microscopy. Vegetative mycelium is characterized by highly cytoplasmic cells rich in ribosomes and mitochondria and with few vacuoles as well as endoplasmic reticulum. Cell walls are thin attaining a maximum thickness of 0.10 μm. During the aggregating phase a prosenchymatous mass of randomly oriented cells is produced by localized elongation and branching of the filaments. The hyphae in this region have the appearance of actively metabolising cells. In the course of the differentiating phase, numerous hyphae of the median zone of the aggregate grow upward and downward to give rise to coremium and rhizomorph primordia respectively. The individual hyphal tips lay parallel to each other and cells of the growing apices retain their meristematic characteristics. At the periphery of the aggregate and to a lesser extent in the subapical rhizomorphic zone, cells reduce their cytoplasmic density as a consequence of a decrease in the number of ribosomes. These cells also increase in size and become isodiametric and vacuolated. During cellular differentiation walls increase steadily in thickness and at the elongating phase they reach 0.30 μm in the rhizomorphic cortex. Mucilaginous material is progressively deposited around hyphae and in the most differentiated zones, coalesce to fill interhyphal spaces. This extracellular matrix seems to play a role in maintaining cohesiveness of the aggregated organs. The tissue in the process of differentiation is scattered with cells highly enriched in mitochondria and with cells virtually undifferentiated. Accumulation of microfilaments takes place in the differentiating zone localized behind the immersed meristematic apex. These structures might be involved in wall synthesis. Glycogen rosettes accumulate in the vegetative mycelium surrounding the aggregating centers, suggesting the possibility of supplying energy during the differentiating processes. The vacuolar system, represented by autophagic vacuoles which are present until the differentiation phase, presumably may also participate in the biochemical changes that occur during aggregation. Coremial cells are characterized by an increase in wall thickness, a highly sinuous plasma-membrane as well as large amounts of mucilaginous compounds accumulated between hyphae, but in all other respects they resemble the cells of actively growing vegetative hyphae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279827
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Ultrastructure of aerial stalk formation by the ciliated protozoanSorogena stoianovitchae (1983)
    Springer
    Protoplasma 116 (1983), S. 125-135 
    Details
    ISSN: 1615-6102
    Keywords: Ciliated protozoan ; Sorogenesis ; Extracellular matrix ; Secretion ; Extrusive organelles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sorogena stoianovitchae Bradbury andOlive is an unusual kinetophragminophoran ciliate characterized by the aggregation of individual trophic cells to form a multicellular sorogen that rises aerially from the medium surface to produce a sorocarp. A light and electron microscope study of sorogenesis revealed how the sorogenic cells produce the stalk. The feeding ciliates contain numerous subpellicular expansions of rough endoplasmic reticulum cisternae that are only one element of the secretory system necessary for stalk formation. Upon aggregation, the stalk secretory system develops further, initially with the proliferation of the subpellicular expansions. Then, during later aggregation and early sorogenesis, other secretory elements appear: stalk material vesicles, dense granule vesicles, and electron lucent vacuoles. These are all derived from the rough endoplasmic reticulum. Only the subpellicular expansions and stalk material vesicles appear to add to the stalk matrix. The dense granule vesicles could be precursors of the stalk material vesicles; the electron lucent vacuoles, which can be demonstrated to contain fibrillar material, are perhaps by-products of the secretory process. Sorogenesis inSorogena occurs by a mechanism unique among the stalk-producing protists that have been studied.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279829
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    Stalk function during sorogenesis by the ciliated protozoanSorogena stoianovitchae (1983)
    Springer
    Protoplasma 116 (1983), S. 136-144 
    Details
    ISSN: 1615-6102
    Keywords: Stalk ; Ciliated protozoan ; Sorogenesis ; Extracellularmatrix ; Ultrastructure ; Secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The sorogenic cells of the haptorid ciliateSorogena stoianovitchae Bradbury andOlive secrete a hydrated, fibrillar matrix that becomes organized to form a stalk. This light and electron microscope study examines the role of the secreted stalk matrix in the development of the sorocarp. The stalk material is secreted as a compact clump or clumps of material that expands as it hydrates. The expanded stalk material is initially viscous, but soon, through dehydration or cross-linking, solidifies to form a sheath. The sheath is the outside layer of the stalk, provides structural support, and controls the expansion of the newly secreted stalk material. The sorogenic cells continue to secrete stalk material that expands once it is outside of the cell. The resulting expansion force is directed upward by the sheath, thereby moving the cells further above the surface. The continued dehydration of the sheath material provides an inwardly directed force that also contributes to the upward movement of the sorogen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279830
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Ultrastructural demonstration of loss and recovery of cytochrome oxidase activity during and after heat induction of microcycle conidiation inNeurospora crassa (1983)
    Springer
    Protoplasma 116 (1983), S. 149-154 
    Details
    ISSN: 1615-6102
    Keywords: Cytochrome oxidase ; Cytochemistry ; Ultrastructure ; Neurospora ; Heat treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cytochrome oxidase (EC 1.9.3.1) activity of conidia of wild-typeNeurospora crassa was detected cytochemically at the ultrastructural level by 3,′-diaminobenzidine (DAB) reaction during heat treatment at 46 °C and after shift down to 25 °C. At 46 °C the decrease in the enzyme activity was shown to be time-dependent (0–10 hours) in the progressively overswelling conidia. Gradual recovery of the DAB reaction occurred in mitochondria of conidia outgrowing conidiogenous germ tubes (microcycle conidiation) when shifted down to 25 °C. Inactivation of cytochrome oxidase was efficiently prevented during heat treatment in the presence of Tween 20. Such conidia no longer overswelled but still required shift down to 25 °C to produce germ tubes with delayed conidiogenous ability.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01279832
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    The effect of UV-B and UV-C radiation on sugar beet leaves (1983)
    Springer
    Protoplasma 117 (1983), S. 7-16 
    Details
    ISSN: 1615-6102
    Keywords: Beta vulgaris ; Chloroplast ; Ultrastructure ; Ultraviolet radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effect of UV-C (254 nm) and UV-B (290–320 nm) radiation on leaves ofBeta vulgaris L. at the ultrastructural level was investigated. Although the damage caused by UV-C radiation was more striking than that resulting from UV-B radiation, several structural changes were seen in the UV-B treated material. Generally the effects of UV-B and UV-C radiation were different, suggesting different mechanisms of action, discernible even at the ultrastructural level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01281779
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    The ultrastructure of the formation and development of the amoeboid tapetum inArum italicum miller (1983)
    Springer
    Protoplasma 117 (1983), S. 116-129 
    Details
    ISSN: 1615-6102
    Keywords: Pollen ; Amoeboid tapetum ; Arum italicum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A tapetum is found around all higher plant meiocytes and is thought to nourish them. It may, in turn, be influenced by their development. The mature tapetal membrane in amoeboid (or periplasmodial) tapeta, of whichArum italicum is an example, fits closely around the developing meiocyte. This description of tapetal ultrastructure starts from the meiotic prophase when the tapetum is still cellular and comprises two rows of cells on the inside of the tetrasporangiate anther. The radial walls of the still cellular tapetum start to dissolve during leptotene of the first meiosis. The lysis begins in the middle lamella in those areas penetrated by the most plasmodesmata. The walls in contact with the meiocytes on the other hand do not disappear until after the first meiosis. At telophase the now fused cytoplasmic tapetal mass begins to extend its joint plasmamembrane, amoeboid fashion, into the loculus. A cluster of microtubules can be seen at the apex of this intrusion apparently initiating or maintaining the shape of the invading plasmamembrane front. The tapetum now adheres closely to the microspores. The tapetal zone closest to the spores has a prominent population of microtubules and just a little ER, whereas the outer zone away from the spores contains all the other organelles. The inner zone, in a squash preparation, is not readily separated from the spores. The microtubules, at the middle microspore stage, are no longer to be seen in a circle around the microspores, but spread out with some lying orthogonal to the now-forming exine surface. In places the tapetal plasmamembrane begins to retract from the exine leaving roughly cone-shaped zones (spines) which become filled with fibrillar material. This material begins to be deposited on the exine surface. These “spines” are both PAS. and Coomassie-blue positive and susceptible to acetolysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01288350
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    The structure and histochemistry of sclerotia ofSclerotinia minor Jagger III. Changes in ultrastructure and loss of reserve materials during carpogenic germination (1983)
    Springer
    Protoplasma 117 (1983), S. 214-225 
    Details
    ISSN: 1615-6102
    Keywords: Histochemistry ; Sclerotia ; Sclerotial germination ; Sclerotinia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cytoplasmic reserves and extracellular substances were progressively broken down and utilized during carpogenic germination of sclerotia ofSclerotinia minor. Glycogen, wall polysaccharides and polyphosphate granules were removed first from regions of the sclerotium distant from developing apothecia, while protein bodies near the base of apothecial stipes were hydrolysed before those further away. The number of profiles of mitochondria and endoplasmic reticulum in cortical and medullary hyphae increased at the onset of germination, indicating increased metabolism in the hyphae. In contrast to developing sclerotia, simple pores with Woronin bodies were frequent in walls and septa during germination. Hyphae that appeared to converge towards the base of apothecial initials retained their cytoplasm and organelles until late in germination and hydrolysis of their reserves was delayed; these are interpreted as translocatory hyphae, although further work is required to determine their role unequivocally. When apothecia were fully developed, hyphae throughout the sclerotium were empty and the walls and extracellular matrix of cortical and medullary hyphae had almost completely broken down.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01281825
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Mitosis in the freshwater red algaBatrachospermum ectocarpum (1983)
    Springer
    Protoplasma 118 (1983), S. 56-70 
    Details
    ISSN: 1615-6102
    Keywords: Carposporophyte ; Cell division ; Mitosis ; Rhodophyta ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitotic ultrastructure was observed in meristematic cells of carposporophyte generations of the freshwater red algaBatrachospermum ectocarpum. Prior to nuclear division, cell elongation occurs resulting in the nucleus being located at the proximal end of the cell and separated by a large central vacuole from a distal “empty region” which the daughter nucleus eventually occupies. In late prophase, nuclear envelope-attached polar rings are situated adjacent to shallow nuclear invaginations. At prometaphase the nuclear invaginations extend deeply into the nucleus forming continuous cytoplasmic channels containing microtubules. Perinuclear ER and a typical equatorial chromosomal plate are formed by metaphase at which time the nuclear envelope lining the cytoplasmic channels has dispersed. Chromosomal and non-chromosomal microtubules converge at the poles where a single, large gap is seen in the otherwise intact nuclear envelope. Polar rings were not detected in the few mitotic cells observed beyond prometaphase but are thought to be present. During anaphase an interzonal midpiece is formed and the distal-most incipient daughter nucleus moves laterally past the central vacuole into the apical “empty region”. Features of mitosis inBatrachospermum are believed to be intermediate between those exhibited by the lower and higher orders of red algae, this being consistent with the taxonomic placement of the genus in theNemaliales, the least advanced order of the classFlorideophyceae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01284747
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    The ultrastructure of nuclear bodies in interphase plant cell nuclei (1983)
    Springer
    Protoplasma 118 (1983), S. 95-103 
    Details
    ISSN: 1615-6102
    Keywords: Nuclear bodies ; Nucleolus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nuclear bodies are found in interphase nuclei of root apices of a number of plant species. They often show differences in structure and position relative to the nucleolus and this has led to an attempt to define two classes of body. However, in some species their separation into two classes on structural grounds alone breaks down, indicating that although they may occupy different positions within the nucleus they may in these particular cases be only different forms of the same body. The two extremes of the range of bodies examined represent what have been called “nucleolus-associated body” (karyosome) and “dense body”. The nucleolus-associated body is typically attached to, or adjacent to, the nucleolus. It is composed of fibrils 4–8 nm wide and often has an open structure showing compound threads or fibrils separated from each other by electron-lucent spaces. The dense body is more compact in structure and typically lies free in the nucleoplasm. Both types of body have an affinity for silver ions which, together with their staining reaction following treatment with EDTA, indicates that they consist of ribonucleoprotein. The characteristics of nuclear bodies found in different plant species have some relationship with the structure and DNA content of the interphase nucleus. Nucleolus-associated bodies are characteristic of species with an areticulate nuclear structure (2 C DNA content 〈6 pg), while dense bodies are common in species with a reticulate nuclear structure (2 C DNA content 〉6 pg). The possible functions of the two forms of nuclear body are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01293065
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Ultrastructural polysaccharide localization in calcifying and naked cells of the coccolithophoridEmiliania huxleyi (1983)
    Springer
    Protoplasma 118 (1983), S. 157-168 
    Details
    ISSN: 1615-6102
    Keywords: Calcification ; Coccolithophorids ; Polysaccharide localization ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Emiliania huxleyi is a marine coccolithophorid which produces coccoliths,i.e., particles consisting of calcite and macromolecular organic material. The coccoliths are formed intracellulary in specialized organelles which comprise a coccolith vesicle (CV) and a reticular body (RB), together forming the CV/RB system or calcifying system. After termination of calcification, the coccolith is extruded and incorporated into the coccosphere,i.e., one or several layers of extracellular coccoliths surrounding the cell. Apart from the coccolith-producing cells (C cells) ofE. huxleyi, there are naked cells (N cells) which seem to have lost the capacity to produce coccoliths but are very similar to the C cells in other morphological respects. Biochemical studies have revealed that polysaccharides may play a regulatory role in calcification. The aim of the present study was to determine the localization of polysaccharides in both C and N cells electron microscopically. For this purpose, a cytochemical staining technique according toThiéry (1967) was applied. The CV/RB system of C cells was conspicuously stained. Due to the excellent stainability of this system, a putative succession of morphological stages during coccolithogenesis could be described. The staining pattern of the N cells closely resembled that of the C cells. It was found, however, that the “calcifying” system of N and C cells differed in both morphology and position. It is suggested that the divergent morphology of the “calcifying” system of N cells accounts for its failure to produce coccoliths.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01293073
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Pre-fertilization ovule development inCapsella: ultrastructure and ultracytochemical localization of acid phosphatase in the meiocyte (1981)
    Springer
    Protoplasma 107 (1981), S. 27-45 
    Details
    ISSN: 1615-6102
    Keywords: Acid phosphatase ; Capsella ; Female meiocyte ; Ovule ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Pre-meiotic and prophase I ovules ofCapsella bursa-pastoris (L.) Medic.(monosporic,Polygonum type of gametophyte development) were fixed routinely or incubated in a modified Gomori medium containing β-glycerophosphate as a substrate. Prior to the beginning of meiosis the potential meiocyte is ultrastructurally similar to the other cells of the nucellus and is distinguished only by its size and position. At the initiation of prophase I dramatic ultrastructural and ultracytochemical changes take place in the female meiocyte. These include the sudden appearance of cytoplasmic structures composed of single and multiple concentric cisternae, distinctive changes in plastids and mitochondria, and the blebbing of 0.3 μm double-membraned vesicles from the nuclear envelope. The concentric cisternae encapsulate portions of cytoplasm containing ribosomes, plastids, mitochondria, ER fragments and vesicles. Both single and multiple concentric cisternae localize high levels of acid phosphatase and function as autophagic vesicles (AVs) that sequester ribosomes and organelles for destruction during meiosis. Plastids stop dividing and become more spherical during prophase I. Some plastids localize acid phosphatase and many show continuities between the outer membrane and the plastid envelope and acid phosphatase-rich RER cisternae. Mitochondria appear as dense, contracted spheres or rods. Some mitochondria localize acid phosphatase but they do not show membrane confluencies with the ER. Some of the plastids and mitochondria that are segregated into the functional megaspore at meiosis II are destroyed but others apparantly survive meiosis and give rise to the plastid and mitochondrial populations of the young gametophyte (Schulz andJensen, unpublished). The lateral and end walls of the meiocyte show patches of intense aniline blue fluorescence and the chalazal end wall of the cell is perforated with large numbers of plasmodesmata.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01275605
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Ultrastructure of the sperms ofPlumbago zeylanica (1981)
    Springer
    Protoplasma 107 (1981), S. 85-107 
    Details
    ISSN: 1615-6102
    Keywords: Male cytoplasmic inheritance ; Plumbago ; Pollen grain ; Pollen tube ; Sperm ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Male gametes ofPlumbago zeylanica were examined in pollen grains and tubes using light and electron microscopy of chemically and physically fixed tissues, and Nomarski interference microscopy of isolated, living sperm cells. Male gametes are elongate, spindleshaped cells containing a nucleus, mitochondria, ER, ribosomes, vesicles, dictyosomes, probable microfilaments, and a variable number of plastids. In mature pollen grains ofP. zeylanica, the two sperm cells are directly linked; they share a transverse cell wall with plasmodesmata and are enclosed together by the inner vegetative cell plasma membrane. One of these two sperms is also associated with the vegetative nucleus as a consistent feature of pollen grain organization. The basis of this association appears to be a long, narrow projection of the sperm cell (averaging 〈 1 μm wide and about 30 μm long) which wraps around the periphery of the vegetative nucleus and occupies embayments of that nucleus. This association is maintained throughout pollen tube growth but becomes less extensive near the completion of tube growth and is severed following tube discharge. The consistent occurrence of the sperm-vegetative nucleus association in pollen grains, tubes and isolated pollen cytoplasm suggests that the two structures may be directly connected, but attempts to visualize this type of connection were unsuccessful. Possibly, the entwining nature and extent of complementary interfaces between vegetative nucleus and sperm may have a role in stabilizing their association. Functionally, the two sperms and vegetative nucleus appear to travel as a linked unit within the pollen tube, possibly increasing the effectiveness of gamete delivery and helping to ensure nearly simultaneous transmission of sperms into the receptive megagametophyte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01275610
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Occurrence of the suberized lamella in leaves of grasses of different photosynthetic types. I. In parenchymatous bundle sheaths and PCR (“Kranz”) sheaths (1981)
    Springer
    Protoplasma 109 (1981), S. 371-401 
    Details
    ISSN: 1615-6102
    Keywords: C4 Photosynthesis ; C4 Types ; Leaf blades ; Poaceae ; Suberized lamella ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Leaf blades of 42 grasses (Poaceae) have been examined ultrastructurally for the occurrence of a suberized lamella in walls of parenchymatous bundle sheaths and PCR (= “Kranz”) sheaths in both large and small vascular bundles. The sample includes species from a range of major grass taxa, and represents all photosynthetic types found in the grasses. Three grasses with unusual C4 leaf anatomy were also included:Alloteropsis semialata, Aristida biglandulosa, Arundinella nepalensis. The presence of a suberized lamella in PCR cell walls was perfectly correlated with photosynthetic type. All PEP-carboxykinase type and NADP-malic enzyme type C4 species examined possessed a suberized lamella in outer tangential and radial walls, but with variable presence in inner tangential walls. PCR cells of bothAlloteropsis semialata andArundinella nepalensis also possessed a suberized lamella. A lamella was totally absent from parenchymatous bundle sheath cells of the C3 species examined (5 spp.) and ofPanicum milioides, a C3-C4 intermediate. It was also absent from PCR cells of NAD-malic enzyme type C4 species (14 spp.) andAristida biglandulosa. The results are discussed in relation to the leakage of CO2 from PCR cells, and to differences between C4 types in δ13C values, chloroplast position in PCR cells, and other anatomical characteristics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01287454
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Ultrastructure of cell division and reproductive differentiation of male plants in theFlorideophyceae (Rhodophyta). Mitosis inDasya baillouviana (1981)
    Springer
    Protoplasma 106 (1981), S. 329-341 
    Details
    ISSN: 1615-6102
    Keywords: Dasya ; Mitosis ; Rhodophyta ; Spermatangia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitosis in the marine red algaDasya baillouviana (Ceramiales, Florideophyceae) was observed with the electron microscope. Most details of the process are quite similar to those observed in the other macroscopic red algae studied to date. However, some minor variations were noted. At late prophase a very small nuclear envelope protrusion (NEP) is formed at each division pole subjacent to the “nucleus associated organelle” known as the polar ring (PR) and 2–3 cisternae of perinuclear endoplasmic reticulum (PER) are commonly present during metaphase-anaphase. In contrast, in the other florideophycean algae where mitosis has been reported, a prominent NEP is present at late prophase (McDonald personal communication,Scott et al. 1980) and only a single cisterna of PER is observed. Additionally, during mid-late interphase and in mitotically-quiescent cells ofDasya, a single cisterna of smooth-surfaced ER is always juxtaposed with each PR. The possible significance of PER in theFlorideophyceae and other multinucleate organisms is discussed as well as the likely functions of spindle-associated smooth ER. It is suggested that ultrastructural features of mitosis should be useful as criteria to aid in the interpretation of the phylogeny of red algae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01275563
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Some aspects of the development of the endodermis and cortex ofTilia cordata andPicea sitchensis (1983)
    Springer
    Plant and soil 71 (1983), S. 147-153 
    Details
    ISSN: 1573-5036
    Keywords: Cortex ; Endodermis ; Picea sitchensis ; Tilia cordata ; Transfer cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The endodermis of bothTilia cordata andPicae citchensis progressess through 3 characteristic phases of development. These developments are delayed somewhat in the xylem pole endodermis ofT. cordata, while inP. sitchensis 3–5 passage cells are found. The cortex ofT. cordata is characterised by very thick walls, while that ofP. sitchensis is characterised by a thick walled layer just outside the endodermis and by 2–3 outer layers of transfer cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182649
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Etude ultrastructurale de la spermatogènese chezTrichinella spiralis Owen 1835 (Nématode trichuroïde) (1981)
    Springer
    Parasitology research 64 (1981), S. 207-215 
    Details
    ISSN: 1432-1955
    Keywords: Ultrastructure ; Spermatogenesis ; Nematoda ; Trichinella spiralis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'étude ultrastructurale de la spermatogénèse chezT. spiralis a permis de retrouver chez cette espèce les caractères morphologiques observés dans la lignée mâle chez la plupart des Nématodes, c'est-à-dire absence de flagelle chez le spermatozoïde, absence de reconstitution de l'enveloppe nucléaire après divisions méiotiques, structure atypique du centriole. Elle a permis de situer le spermatozoïde par rapport aux classifications antérieurement proposées.
    Notes: Abstract The ultrastructural study of spermatogenesis inT. spiralis demonstrated the main characteristics of the male germ cells in the class Nematoda, i.e. lack of flagella, lack of reconstitution of the nuclear envelope after the meiotic divisions, and atypical structure of the centriole. The spermatozoon ofT. spiralis was compared with previous classifications of the Nematoda spermatozoa.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00930498
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    The ultrastructure of the epidermis of the redia ofParorchis acanthus nicoll (Digenea; Philophthalmidae) (1981)
    Springer
    Parasitology research 65 (1981), S. 19-30 
    Details
    ISSN: 1432-1955
    Keywords: Parorchis acanthus ; Redia ; Ultrastructure ; Epidermis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Regional and age differences in the epidermis of the redia ofP. acanthus have been studied by transmission electron microscopy. The depth of the outer cytoplasmic epidermis increases by four times from stage I to stage III and the microvilli double their length and branch by stage II. Electron-dense and electron-lucent membrane bound bodies are present in all stages, the latter being released onto the surface as vesicles. Multivesicular bodies appear in stage III. All are formed in one type of secretory epidermal cell body. Anterior and posterior concentric folds, of thickened outer cytoplasmic epidermis only, increase the surface area and also the diameter of the redia on contraction. In stages I and II the apical regions of the ventro-lateral processes and birth papilla, and the lattice pattern on the posterior papilla, each consisting of thickened outer cytoplasmic epidermis only, may provide rigidity and support during migration. The uniciliate sensory receptors appear to be mechanoreceptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00926550
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Ultrastructure of trout spermatozoa: Changes after dilution and deep-freezing (1983)
    Springer
    Cell & tissue research 228 (1983), S. 205-218 
    Details
    ISSN: 1432-0878
    Keywords: Spermatozoa ; Ultrastructure ; Deep-freezing ; Sperm manipulation ; Trout
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Trout spermatozoa taken from the testis, vas deferens and ejaculate are described at the ultrastructural level. The morphology of the spermatozoa head, changes in the middle-piece structure, and the relationship between the centrioles and the flagellum were studied under consideration of their role in the reproduction of this species. Morphological changes observed after dilution of the spermatozoa in freshwater or saline and subsequent freezing deserve attention in connection with certain manipulations used in fish farms and laboratories.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00204873
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Circadian variations in pinealocytes of the Chinese hamster, Cricetulus griseus (1983)
    Springer
    Cell & tissue research 228 (1983), S. 231-244 
    Details
    ISSN: 1432-0878
    Keywords: Pineal gland ; Circadian rhythm ; Synaptic ribbon ; Ultrastructure ; Chinese hamster (Cricetulus griseus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Circadian morphological variations of pinealocytes in the superficial pineal of the Chinese hamster (Cricetulus griseus) were studied using quantitative electron-microscopic techniques. The volume of the nucleus and cytoplasm of pinealocytes exhibited similar circadian variations, with the maximum around the middle of the light period and the minimum during the first half of the dark period. Synaptic ribbons in pinealocytes were classified into three groups, type-1, −2 and −3 synaptic ribbons, which appeared as rods, round or irregular bodies and ring-shaped structures, respectively; a synaptic ribbon index was determined for the respective types. The synaptic ribbon index was expressed as the number of synaptic ribbons in the pinealocyte profile representing the cell size. The type-1 synaptic ribbon index, which was smallest during the second half of the light period, was increased during the dark period. The length of straight or slightly curved rods showed a 24-h change similar to that of the type-1 synaptic ribbon index; the length of the rods was maximal during the first half of the dark period and minimal at the end of the light period. There was no apparent circadian variation in the type-2 synaptic ribbon index. The type-3 synaptic ribbon index was higher during the light period than during the dark period; the index attained zero 3h after the onset of darkness and, thereafter, increased gradually.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00204875
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of enkephalin in the lateral septum of the guinea-pig brain (1983)
    Springer
    Cell & tissue research 228 (1983), S. 265-276 
    Details
    ISSN: 1432-0878
    Keywords: Met- and leu-enkephalin ; Immunocytochemistry ; Ultrastructure ; Lateral septum ; Guinea-pig brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By the use of antisera to met-enkephalin and leu-enkephalin, enkephalin-containing structures were visualized in the lateral septum of the guinea-pig brain. The present results do not reveal immunoreactive perikarya in this area. The immunostaining is exclusively located in numerous nerve fibers and endings mostly encompassing neuronal perikarya, which accounts for the fact that at the light-microscopic level cellular somata appear to be immunostained. The immunoreactive terminals and fibers contain granules approximately 110nm in diameter and synaptic vesicles. The origin and the functional role of these numerous enkephalin terminals remain to be established. This work was supported by a grant from INSERM N∘ 804012
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00204878
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    The effects of colchicine on the distribution of glycoprotein-containing vesicles in epithelial cells of the murine colon (1983)
    Springer
    Cell & tissue research 228 (1983), S. 323-335 
    Details
    ISSN: 1432-0878
    Keywords: Ultrastructure ; Colonic epithelium ; Colchicine ; Vesicles ; Glycoproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In murine colonic epithelial cells, cell-coat glycoproteins are transported to the cell surface in vesicles that originate at the Golgi apparatus. To determine the role of microtubules in the movement of these vesicles the antimicrotubule agent colchicine was injected into mice at several time intervals prior to sacrifice. In the mice that were treated with colchicine for 4.5 h it was observed that the polarity of the cells was disturbed. The Golgi apparatus and nucleus often appeared interchanged in their positions. The glycoprotein-containing vesicles, normally located apically, were sparse in that location, but abundant near the lateral plasma membranes of the cells at the level of the nucleus and Golgi apparatus. Staining by the periodic acid-chromic acid-silver methenamine technique for glycoproteins clearly revealed the reduction of vesicles apically and accumulation of vesicles laterally. The mechanism responsible for the movement of the vesicles to this location is unclear. It is suggested that the accumulation of vesicles in the lateral region may reflect some hindrance in the fusion of the vesicles with the lateral cell membranes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00204882
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Structure of the non-lymphoid cells during the postnatal development of the rat lymph nodes (1983)
    Springer
    Cell & tissue research 229 (1983), S. 219-232 
    Details
    ISSN: 1432-0878
    Keywords: Lymph nodes ; Postnatal development ; Fibroblastic reticulum cells ; Interdigitating cells ; Deep cortex units ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study describes the postnatal development of the nonlymphoid cells with special reference to the fibroblastic reticulum cells (FRCs) and interdigitating cells (IDCs). The first lymphocytes of the neonatal lymph nodes are located in the developing deep cortex units (DCUs) identified by the Gomori's technique for reticulin fibres. Ultrastructural studies demonstrate that FRCs form the stroma of the DCUs. By light and electron microscopy, it is demonstrated that FRCs occupy the outer cortex in the following stages of development of the lymph nodes. Thus, FRCs form the stroma of the primary follicles and, later, are transformed in follicular dendritic cells (FDCs) of the germinal centres. Immature or pro-IDCs appear as migrating elements in the deep cortex of lymph nodes of the neonatal rats. The ultrastructure of the pro-IDCs resembles that of the mature IDCs but not that of the phagocytic cells. Pro-IDCs are transformed into mature IDCs whose cytoplasmic expansions contact lymphocytes via tight junctions. Some of these lymphocytes are likely apposed to FRCs of the DCUs. No cells containing Birbeck granules were found in the parenchyma of the lymph nodes during the postnatal development. The role of these nonlymphoid cells is discussed with respect to the immunologic function of mammalian lymph nodes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217894
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Cytodifferentiation of the paraventricular nucleus in the chick embryo (1983)
    Springer
    Cell & tissue research 229 (1983), S. 281-297 
    Details
    ISSN: 1432-0878
    Keywords: Paraventricular nucleus ; Hypothalamus ; Development ; Golgi study ; Ultrastructure ; Chick embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The developmental changes in the cytoarchitecture of the hypothalamic paraventricular nucleus of the chick embryo were studied with particular emphasis on the differentiation of the magnocellular neurons. These cells can be distinguished from the parvocellular elements starting from stages 34–35 (Hamburger and Hamilton 1951) in Golgi-impregnated specimens. At the same stages, electron microscopy reveals dense-core granules, resembling the characteristic elementary granules of the neurosecretory material in the cytoplasm of the larger neurons. In addition, a few immature synapses were observed on these magnocellular perikarya. The present observations suggest that the early onset of neurosecretion in this area may be neurally regulated during early phases of development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214976
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Putative sense organs on the palliai tentacles of the limpet, Patella vulgata (L.) (1983)
    Springer
    Cell & tissue research 231 (1983), S. 663-674 
    Details
    ISSN: 1432-0878
    Keywords: Ciliary tuft ; Pallil tentacles ; Patella vulgata ; Sensory ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure and ultrastructure of ciliary tufts on the pallil tentacles of the limpet Patella vulgata (L.) are described. The tip of each tentacle is covered by a dense crown of tufts and additional tufts can be seen scattered evenly across the surface of each tentacle. The cilia are nonmotile and nerve fibres run from the base of the ciliated cells suggesting a sensory function. Comparisons are made with ciliary tufts found in a Pacific species of limpet, Acmaea scutum, and other molluscan sensory structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218124
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Structural studies of the adrenal zona glomerulosa and renal juxtaglomerular apparatus in pregnant sheep (1983)
    Springer
    Cell & tissue research 232 (1983), S. 177-187 
    Details
    ISSN: 1432-0878
    Keywords: Pregnancy ; Adrenal zona glomerulosa ; Juxtaglomerular apparatus ; Ultrastructure ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural changes in the adrenal zona glomerulosa and renal juxtaglomerular apparatus have been examined during normal pregnancy in sheep. As pregnancy progressed, increasing numbers of cells in the adrenal zona glomerulosa displayed mitochondria with straight tubular “rod-like” structures replacing their normal lamelliform cristae; groups of cells showing these mitochondrial changes were predominantly located in the middle and superficial regions of the zona glomerulosa, but at all stages remained interspersed with cells with apparently normal mitochondria. In the same animals, the renal juxtaglomerular index was raised, reflecting an increase in renin storage, and juxtaglomerular myoepithelioid cells showed increased numbers of cytoplasmic granules, but no apparent increase in granular endoplasmic reticulum and Golgi profiles; there were no distinguishing morphological changes in juxtaglomerular peripolar cells. These findings provide morphologic evidence of stimulation of the adrenal zona glomerulosa in association with increased juxtaglomerular renin storage during pregnancy. The mitochondrial changes observed in an increasing proportion of cells in the zona glomerulosa closely resemble those seen in sodium-depleted animals, and may reflect the altered steroidogenic capacity of the adrenal gland in pregnant sheep. The finding of groups of cells displaying altered mitochondria lying next to cells with normal mitochondria suggests the presence of cells with different sensitivities to stimuli for aldosterone production or may indicate the presence of different cell types in the zona glomerulosa responding to different stimuli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222382
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    The ultrastructure of oesophageal striated muscle in the guinea-pig and marmoset (1983)
    Springer
    Cell & tissue research 234 (1983), S. 365-376 
    Details
    ISSN: 1432-0878
    Keywords: Oesophageal striated muscle ; Ultrastructure ; Guinea-pig, marmoset
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characteristics of oesophageal striated muscle from guinea-pig and marmoset have been examined using transmission electron microscopy and compared with ultrastructural features of skeletal muscle. The findings show that, although similar to skeletal muscle, oesophageal striated muscle exhibits important differences in the arrangement of its muscle fibres and their motor innervation. It was also found impossible to classify oesophageal striated muscle according to the usual ultrastructural criteria since its motor endplates bore a greater resemblance to those of intrafusal skeletal muscle fibres. The consideration of these differences in conjunction with characteristics revealed elsewhere by other techniques confirms the unique nature of oesophageal striated muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213774
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    The glomerulus of a stenohaline fresh-water teleost, Carassius auratus gibelio, adapted to saline water (1981)
    Springer
    Cell & tissue research 220 (1981), S. 73-85 
    Details
    ISSN: 1432-0878
    Keywords: Glomerulus ; Stenohaline fresh-water teleost ; Salt-water adaptation ; Kidney ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Prussian carp, Carassius auratus gibelio, were maintained in aquaria with a salinity of 15‰ for 3 months. More than 90% of the glomeruli disappeared from the tissue as a result of the adaptation to saline water. Kidney tissue was excised and prepared for electron microscopy after perfusion fixation in situ. The fine structure of the renal corpuscle was compared with the normal ultrastructure of glomeruli of control fish from fresh-water aquaria. The main alterations include retraction of the endothelium from the basement membrane, widening of the subendothelial region, folding of the thickened basement membrane and epithelial layer, and the dislocation of slit diaphragms. The findings are discussed in relation to developmental stages of mammalian glomeruli and glomeruli from tissue cultures. The structural changes of the rudimentary glomeruli of the carp kept in 15‰ salt water differ from those observed in euryhaline fish from sea water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209967
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Developmental stages and localization of peroxidatic activity in the leucocytes of three teleost species (Cyprinus carpio L.; Tinca tinca L.; Salmo gairdneri Richardson) (1981)
    Springer
    Cell & tissue research 220 (1981), S. 163-180 
    Details
    ISSN: 1432-0878
    Keywords: Leucocytes ; PO-reactivity ; Teleosts (Cyprinus carpio L., Tincatinca L., Salmo gairdneri R.) ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural localization of peroxidase (PO) in the leucocytes of three teleosts (Cyprinus carpio L., Tinca tinca L., Salmo gairdneri R.) has been investigated using the 3,3′-diaminobenzidine method. In the heterophilic granulocytes the granules show a species specific structure and are PO-positive at pH 7.6. They can be traced back to small granules arising near the Golgi apparatus (GA) in the promyelocyte. They coalesce to form larger granules and gradually change into the mature type. Myelocytes contain small unreactive granules, and these represent a second granule population. Eosinophils contain one PO-positive granule type (at pH 9), and these granules show a varying density during cell maturation. Basophils are present only in the Cyprinid species, and contain unreactive granules originating from precursors displaying a weakly positive reaction at pH 7.6. The active secretory organelles (RER, GA) are PO-negative, except for a weakly positive reaction in the flocculent matrix of the inner G-cisternae. In promonocytes and monocytes the granules are unreactive, but in the macrophages PO-positive staining occurs in a few small to medium sized granules, and in large vacuoles. At least some of these latter are apparently derived from phagolysosomes containing digested erythrocytes. Thrombocytes and lymphocytes are unreactive. The successive development of PO-positive and negative granule populations in the heterophils, and the PO-reactivity of eosinophils and basophils, show some similarities to the corresponding cells in higher vertebrates, but an analogous PO-positive (“azurophil”) granule type in monocytes seems to be absent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209975
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Structure of the pars distalis in the adult tammar wallaby (Macropus eugenii) (1983)
    Springer
    Cell & tissue research 229 (1983), S. 155-174 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary ; Tammar wallaby ; Marsupialia ; Ultrastructure ; Immunohistochemistry ; Cell types
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An immunohistochemical, light- and electron-microscopial study was made of the pars distalis in adult tammar wallabies (Macropus eugenii). The pars distalis of this marsupial mammal was divided into three regions, based on the distribution of cell types within the gland. Somatotropic, mammotropic, luteotropic, folliculotropic, corticotropic and thyrotropic cells were identified on the basis of their immunohistochemistry, cytology and ultrastructure. Non-granulated (folliculo-stellate) cells, identified in electron micrographs, were found throughout the pars distalis. Somatotropic cells were predominant in the posterior pars distalis in all animals examined. In the single male specimen and in the non-lactating females examined, small numbers of apparently inactive mammotropic cells were scattered throughout the pars distalis; the same cell type was apparently active and present in considerable numbers in lactating females. Only one morphological type of gonadotropic cell was evident; these cells were scattered throughout the pars distalis, but in largest numbers in the median region. Small numbers of thyrotropic cells were found, most commonly in the anterior pars distalis. Corticotrops were also observed in moderate numbers, predominantly in the anterior regions of the pars distalis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217888
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Ultrastructure of sensilla on the antennal pedicel of the brown planthopper Nilaparvata lugens Stal (Insecta: Homoptera) (1983)
    Springer
    Cell & tissue research 228 (1983), S. 313-322 
    Details
    ISSN: 1432-0878
    Keywords: Olfactory ; Sensilla ; Ultrastructure ; Insects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning- and transmission electron-microscope studies of the sensilla of the pedicel of Nilaparvata lugens have revealed an elaborate plaque organ and three structurally different types of trichoid hairs. Each plaque organ is innervated by 120–150 neurons arranged in groups. The porous sensory cuticle is folded into finger-like projections and is surrounded by protective non-sensory denticles. Trichoid sensilla differ in number of neurons, appearance of dendrites and arrangement of pores. Type I, innervated by 2 neurons, has pores along its length and is probably olfactory in function. Types II and III are innervated by one and five neurons, respectively, and the absence of pores along the hair shaft indicates a possible gustatory role. The importance of these sensilla is discussed with reference to the behaviour of this important insect pest.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00204881
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Topography, ultrastructure and phagocytic capacity of avian lymph nodes (1983)
    Springer
    Cell & tissue research 228 (1983), S. 389-403 
    Details
    ISSN: 1432-0878
    Keywords: Lymph node, avian ; Ultrastructure ; Macrophages ; Phagocytic capacity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the avian lymph node (ALN) is characterized by a thin capsule, thin lymphoreticular cords, and an absence of trabeculae. It is not possible to subdivide the ALN into cortex, paracortex and medulla, or to subdivide the system of sinuses into marginal, trabecular and medullary divisions. The lymphoreticular cords contain avian germinal centers (AGC) with B-lymphocytes and the area of T-lymphocytes. Postcapillary venules are responsible for the recirculation of lymphocytes. Sinus reticular cells do not exist in the ALN, but free macrophages are present. The phagocytic capacity of the macrophages was determined by injection of vital dyes (India ink, Berlin blue) and inoculation with Candida cells. Macrophages filled with markers migrate from the lymph sinuses into the lymphoreticular cords and further into the AGC. The mobility of the macrophages is remarkably lower after phagocytosis of Candida cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00204887
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Differentiation and transdifferentiation of adrenal chromaffin cells of the guinea pig (1983)
    Springer
    Cell & tissue research 229 (1983), S. 299-308 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal chromaffin cells ; Plasticity ; Transplants ; Kidney capsule ; Ultrastructure ; Catecholamine biochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histochemical, ultrastructural and biochemical studies (quantitative determinations of catecholamines (CA) and phenylethanolamine N-methyltransferase (PNMT) activity) were carried out on autologous transplants of adult guinea-pig adrenal medulla under the kidney capsule, in order to investigate the specific influences of a virtually nerve-free environment in comparison to those mediated by a densely innervated one such as in the iris (cf. Unsicker et al. 1981). Three weeks after transplantation chromaffin cells survived well, most cells maintaining their morphological identity in terms of adrenaline (A) storage, although biochemically measured A and PNMT had dramatically decreased. Chromaffin cells in transplants extended neurite-like processes in an identical fashion as seen in transplants to the anterior chamber of the eye and in culture. Chromaffin cells were frequently connected by synaptoid contacts, but did not receive cholinergic synapses as observed in transplants to the iris. It may be concluded that the growth factor(s) eliciting neurite outgrowth from transplanted chromaffin cells are rather ubiquitously present, independent of whether the transplantation site is sparsely or richly innervated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214977
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Structural and functional studies of the adrenal zona glomerulosa in sodium-depleted and sodium-loaded sheep (1983)
    Springer
    Cell & tissue research 229 (1983), S. 515-531 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal zona glomerulosa ; Ultrastructure ; Sodium depletion ; Sodium loading ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of alterations in sodium status upon the morphology of the adrenal zona glomerulosa in sheep have been examined qualitatively and quantitatively, using lightand electron microscopy, and correlated with functionally related biochemical data. With severe sodium depletion induced by parotid-cannula drainage, there was mitotic activity throughout the zona glomerulosa, and glandular cells showed striking ultrastructural changes. These changes particularly affected mitochondria, which were enlarged, rounded and showed replacement of their normal lamelliform cristae by thin elongated cristal elements and bundles of tubular “rod-like” structures. Quantitative morphometric studies showed an increase in the volumes of zona glomerulosa cells, nuclei, mitochondria, smooth and granular endoplasmic reticulum, and Golgi profiles. In contrast, with dietary sodium loading, zona glomerulosa cells appeared shrunken and showed cytoplasmic lipid accumulation; mitochondria and other organelles were not significantly altered. The correlation of the ultrastructural cytological alterations in zona glomerulosa cells in sodium-depleted sheep with raised blood aldosterone levels suggests that such morphologic changes reflect a heightened capacity of these cells for aldosterone biosynthesis and secretion. These changes may also account for the increased sensitivity of the zona glomerulosa to aldosterone-producing stimuli during sodium deficiency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00207695
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    Variation in sperm morphology in the Australian rodent genus, Pseudomys (Muridae) (1983)
    Springer
    Cell & tissue research 229 (1983), S. 611-625 
    Details
    ISSN: 1432-0878
    Keywords: Spermatozoa ; Ultrastructure ; Pseudomys (Muridae, Rodentia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sperm morphology among the various members of the genus Pseudomys showed great interspecific variation. In P. apodemoides, P. desertor, P. fumeus, P. gracilicaudatus, P. hermannsburgensis, P. higginsi and P. nanus the sperm head was bilaterally flattened and possessed three hooks, the length of which varied somewhat between species. The top hook contained nuclear, subacrosomal and acrosomal material, whereas the two lower ventral hooks displayed largely only an extension of the subacrosomal material. Four other species of Pseudomys had no ventral hooks in their sperm head. In P. novaehollandiae there was a single long top hook, whereas in P. pilligaensis it was almost nonexistent. Neither the sperm head of P. delicatulus, nor that of P. shortridgei possessed any hooks; the former became narrower towards the tip, whereas the latter was spatulate in shape. The acrosome covered about two thirds of the nucleus and varied considerably in shape between species. Insertion of the connecting piece of the tail occurred on the lower ventral side of the sperm head in all species with a long top hook but was nearly basal in P. delicatulus and midbasal in P. shortridgei. The ultrastructure of mid and principal pieces was similar among species, but the number of gyres of mitochondria ranged from about 64 to 100.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00207701
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Ultrastructure of sensory receptors on the labium of the rice brown planthopper (1983)
    Springer
    Cell & tissue research 230 (1983), S. 353-366 
    Details
    ISSN: 1432-0878
    Keywords: Homoptera ; Labium ; Sensilla ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the sensory receptors located on the labium of the rice brown planthopper is described; possible functions of individual receptors are suggested on morphological grounds. Uniporous chemosensilla which may or may not possess a mechanoreceptive dendrite, domed multiporous chemosensilla, and mechanoreceptive pegs are present on the flattened labial tip. Mechanoreceptive pegs are distributed over the labium. The fine structure of a multilobed sensillum located on either side of the labium is also described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213809
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Effects of melatonin on synaptic ribbons in pinealocytes of the Chinese hamster, Cricetulus griseus (1983)
    Springer
    Cell & tissue research 233 (1983), S. 59-67 
    Details
    ISSN: 1432-0878
    Keywords: Pineal gland ; Synaptic ribbon ; Melatonin ; Ultrastructure ; Chinese hamster (Cricetulus griseus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of melatonin on synaptic ribbons (SR) in pinealocytes of the Chinese hamster (Cricetulus griseus) were examined. SR were classified into types 1, 2 and 3, which appear as rods, round or irregular bodies and ring-shaped structures, respectively; a synaptic ribbon index (SR index) was determined for the three types. Administration of two doses of 1.5 mg/kg melatonin at noon and 3 p.m. causes an increase in the type-1 and type-2 SR indices 3 h after the second injection in hamsters kept under alternating light and dark conditions (lights on from 7 a.m. to 7 p.m.). Likewise, in animals that are exposed to extended light for 6 h and receive two doses of melatonin at 7 p.m. and 10 p.m., an increase in the type-1 and type-2 SR indices occurs 3 h after the second injection. The increase in the type-2 SR index induced by melatonin administration to hamsters exposed to extended light is greater than the increase in the type-1 SR index under the same experimental conditions. Type-2 SR index, but not type-1 SR index, increases following bilateral superior cervical ganglionectomy. An increase in type-1 and type-2 SR indices occurs at 6 p.m. in ganglionectomized animals administered two doses of melatonin 6 h (noon) and 3 h (3 p.m.) before the time of sacrifice. No significant change is observed in type-3 SR index in animals subjected to any of the above treatments. The results indicate that exogenous melatonin may act directly on pinealocytes of the Chinese hamster to cause an increase in size and/or number of the type-1 and type-2 SR. Type 3-SR may have a role different from that of type-1 and type-2 SR; type-1 and type-2 SR may be functionally related.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222232
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    A peculiar myofibrillar pattern in the murine muscletendon junction (1983)
    Springer
    Cell & tissue research 233 (1983), S. 227-231 
    Details
    ISSN: 1432-0878
    Keywords: Muscle-tendon junction ; Ultrastructure ; Myofibrillar pattern ; M. flexor digitorum longus ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The muscle-tendon junctions of adult mice show a special arrangement of myofibrils. Essentially, the myofibrils are oriented in an anchor-like manner in the large finger-shaped processes of the muscle fiber, which contain “mitochondrial sacks” (Demmel et al. 1979) in a subsarcolemmal position. Furthermore, the single myofibril frequently branches out into smaller fibrils. It is suggested that due to the three-dimensional arrangement, these processes gain a high rigidity during contraction, thus maintaining their shape and preserving the “mitochondrial sacks”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222246
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Spermiogenesis in the rainbow trout (Salmo gairdneri) (1983)
    Springer
    Cell & tissue research 233 (1983), S. 265-284 
    Details
    ISSN: 1432-0878
    Keywords: Spermiogenesis ; Rainbow trout ; Ultrastructure ; Spermatids ; Chromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an ultrastructural study on the spermiogenesis of the rainbow trout (Salmo gairdneri R.) four spermatogenetic stages were identified. In young round spermatids, the nuclear chromatin was first heterogeneous (euchromatin and heterochromatin). Subsequently, it became more homogeneous and started to condense in the form of coarse granules and fibers and then into fibrils associated in ribbon-like elements which eventually partly fused together. During early spermiogenesis, a juxtanuclear vacuole appeared in the area where the nuclear envelope was specialized due to condensation of material between the two envelopes and a slight accumulation of nuclear material. This area was finally located in the anterior part of spermatids and spermatozoa; it probably plays a role during fertilization. A flagellar rootlet appeared early in spermiogenesis; it may play a role in the attachment of the flagellum to the nucleus since it persisted until the centriolar complex was definitively fixed in the implantation fossa. The flagellum did not display a plasma membrane and was first located in the cytoplasm, but when it was later extruded from the cell, it acquired a membrane. The cytoplasm was rich in ribosomes (free or in small groups) but poor in membranous organelles. The few mitochondria polarized around the centriolar complex were finally organized into an annular mid-piece. The spermatids remained connected by intercellular bridges until the end of spermiogenesis. The complexity of trout spermiogenesis is intermediate between that in poecilids and that in carp and pike, which have very simple spermatozoa. The role of the material from the nucleus and the cytoplasm reaching the Sertoli cell in the control of spermatogenesis has been discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238295
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Erythropoiesis in the thymus of the spotless starling, Sturnus unicolor (1983)
    Springer
    Cell & tissue research 232 (1983), S. 445-455 
    Details
    ISSN: 1432-0878
    Keywords: Avian thymus ; Intrathymic erythropoiesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Although previously described in other avian species, intrathymic erythropoiesis is a remarkable feature of the thymus of Sturnus unicolor. In discrete stages of the life cycle of this species, erythroblasts and mature erythrocytes occupy large areas of the thymic cortex and cortico-medullary border. Simultaneously, degenerated thymocytes and epithelial-reticular cells occur in the same areas. The relationship between intrathymic erythropoiesis, degeneration of cortical lymphocytes and epithelial-reticular cells, and macrophage activity is discussed and related to a possible functional role of sex hormones in this phenomenon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213799
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Ultrastructural and functional development of macrophages in the dermal tissue of rat fetuses (1983)
    Springer
    Cell & tissue research 232 (1983), S. 539-552 
    Details
    ISSN: 1432-0878
    Keywords: Fetal macrophages ; Subepidermal mesenchyme (dermal tissue) ; Rat fetus ; Ontogeny ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After about 12 days of gestation, fetal macrophages begin to appear in the subepidermal mesenchyme of rat fetuses. The macrophages are ultrastructurally characterized by cytoplasmic vacuoles, abundant polyribosomes and long filopodia. Immunocytologically, they possess Fc and complement (C3) receptors on the cell surface and are capable of immune phagocytosis, Latex or carbon phagocytosis, and glass adherence. From 15 days of gestation, lysosomal granules and miropinocytic vesicles gradually develop, together with an enlargement of Golgi complexes, whereas the number of polysomes and the number and size of cytoplasmic vacuoles are gradually reduced when gestation ends. Finally, the macrophages become amoeboid. Non-specific esterase and endogenous peroxidase activities are always absent in these macrophages. In culture experiments with cell suspensions prepared from the mesenchyme, fetal macrophages show a similar maturation process. Autoradiography with 3H-thymidine demonstrates a high proliferative capacity of the macrophages, particularly during the fetal stage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216427
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    The in vitro development of the pupal integument and the effects of ecdysteroids in Tenebrio molitor (Insecta, Coleoptera) (1983)
    Springer
    Cell & tissue research 232 (1983), S. 493-511 
    Details
    ISSN: 1432-0878
    Keywords: Ecdysteroids ; Epidermis ; In vitro differentiation ; Tenebrio ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to study the pupal-adult metamorphosis of Tenebrio in vitro, pupal sternites of different ages were cultured in Landureau's medium and their development systematically observed by electron microscopy. In hormone-free medium, explants taken from young pupae do not secrete pupal postecdysial cuticle in vitro, and the epidermis spontaneously detaches from the pupal cuticle. On the contrary, explants taken from pharate adults continue to secrete adult preecdysial cuticle in vitro, and the epidermis never detaches from the cuticle. Ecdysterone in physiological concentrations (0.2 to 4 μg/ml) induces the secretion of a new cuticle in explants from young pupae but the epidermis remains undifferentiated. Ecdysone is necessary for the induction of some adult differentiation. Moreover, the quality of the cuticle secreted in vitro is increased by the addition of 2% foetal calf serum; the best results have thus far been obtained in a medium containing 0.2 μg/ml ecdysone, 1 μg/ml ecdysterone, and 2% foetal calf serum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216424
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Electron-microscopical study of the operculum in anuran tadpole after extirpation of the right forelimb during metamorphosis (1983)
    Springer
    Cell & tissue research 232 (1983), S. 513-527 
    Details
    ISSN: 1432-0878
    Keywords: Skin ; Operculum ; Fenestration ; Ultrastructure ; Anura ; Metamorphosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The process of histolysis and fenestration of the skin of the prospective opercular perforation region of Rana japonica after extirpation of the right forelimb was observed during metamorphosis by transmission and scanning electron microscopy. Epidermal cells of the belly of the tadpole, including the operculum, are extremely similar in their ultrastructure. Epidermal cells of the prospective opercular perforation region during metamorphosis become thin and vacuolated especially around the nucleus perhaps by autolysis, associated with lysosomal activity. The histolysis and formation of the perforation of the operculum occurs in the complete absence of forelimb. Macrophages containing phagosomes and lymphocytes or other blood cells are almost always found in the intercellular epidermis. Necrotic epidermal cells progressively separate by cleft formation and slough off without cornification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216425
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Ultrastructural studies on the nucleoli of the follicle cells in the Lizards Acanthodactylus scutellatus hardyi and Eremias brevirostris (1981)
    Springer
    Cell & tissue research 214 (1981), S. 169-180 
    Details
    ISSN: 1432-0878
    Keywords: Nucleolus ; Pyriform cells ; Intermediate cells ; Lizards ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the nuclei in the ovarian follicular cells has been examined in the lizards Acanthodacylus scutellatus hardyi, and Eremias brevirostris. During certain growth stages, the nuclei of the intermediate and the pyriform cells become large and conspicuous, and usually contain numerous morphologically variable nucleoli. The latter may be nucleolonemal, compact, ring-shaped, “filamentous”, “fine-filamentous”, “amorphous” or “course-granular” in type, and the number and type in each nucleus seems to be related to the developmental stage. The type of nucleolus may indicate different phases of activity in the nucleus and may also suggest an association with the production of different types of RNA.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235154
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Identification and morphometric evaluation of the synapses of optic nerve afferents in the optic tectum of the axolotl (Ambystoma mexicanum) (1981)
    Springer
    Cell & tissue research 214 (1981), S. 593-611 
    Details
    ISSN: 1432-0878
    Keywords: Synapses ; Optic afferents ; Optic tectum ; Axolotl ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The terminals of retinal afferents in the tectum of the axolotl have been identified ultrastructurally using techniques of horseradish peroxidase-filling and degeneration. The mitochondria in filled structures show a characteristic electron-lucent matrix. After both eyes have been removed, terminals with light mitochondria disappear from the area known to receive an optic input. In this area the presence of light mitochondria is almost always diagnostic of the retinal origin of a bouton. The synapses are similar to those assumed to be of retinal origin in other vertebrates. Detailed morphometric analysis has been carried out on identified optic synapses in the optic tectum of the axolotl.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233499
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    The ultrastructure of the innervation of the intestinal wall in the teleosts Myoxocephalus scorpius and Pleuronectes platessa (1981)
    Springer
    Cell & tissue research 214 (1981), S. 651-658 
    Details
    ISSN: 1432-0878
    Keywords: Intestine ; Teleost ; Ultrastructure ; Innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The innervation of the intestinal wall in the teleosts Myoxocephalus and Pleuronectes was examined electron microscopically. Two classes of axons can be identified. The first, which is in the majority, contains numerous 50–150 nm granular vesicles as well as some 40–50 nm agranular vesicles while the second contains predominantly the 40–50 nm agranular vesicles. Chromate/dichromate staining methods suggest that the first type is aminergic. Both types lie in close association with the perikarya of intrinsic myenteric neurons but only axons containing predominantly agranular vesicles have synaptic membrane specialisations. No axon bundles pass into the longitudinal muscle layer in Myoxocephalus gut and though some do in Pleuronectes, they do not closely approach the smooth muscle cells. Axons containing large granular vesicles lie in intimate contact with the myocytes of the circular muscle layer. Both axon types pass through the submucosa to form a plexus underneath the mucosal epithelium. Varicosities containing agranular or granular vesicles are separated from the epithelial cells by a gap of about 200 nm in which lies a basal lamina.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233504
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Nerves containing substance P, vasoactive intestinal polypeptide, enkephalin or somatostatin in the guinea-pig taenia coli (1981)
    Springer
    Cell & tissue research 215 (1981), S. 21-39 
    Details
    ISSN: 1432-0878
    Keywords: Peptidergic nerves ; Guinea-pig taenia coli ; Substance P ; Vasoactive intestinal peptide ; Somatostatin ; Enkephalin ; Ultrastructure ; Histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The guinea-pig taenia coli is rich in peptide-containing nerves. Nerve fibres containing substance P (SP), vasoactive intestinal peptide (VIP), or enkephalin, were numerous in the smooth muscle while somatostatin fibres were very few. Nerve fibres displaying SP or VIP immunoreactivity were numerous in the myenteric plexus. Enkephalin nerve fibres were fairly numerous in the plexus while somatostatin nerve fibres were sparse. Nerve cell bodies containing immunoreactive SP or VIP were regularly seen in the plexus. Delicate varicose elements of the different types of nerve fibres were found to ramify around nerve cell bodies in a manner suggestive of innervation. In the electron microscope the various peptide-storing nerve fibres (i.e., elements containing SP, VIP or enkephalin) were found to contain a varying number of fairly large, electron-opaque vesicles in the varicose swellings. These vesicles represent the storage site of the neuropeptides. The isolated taenia coli responded to electrical nerve stimulation with a contraction. After cholinergic and adrenergic blockade the contractile response was replaced by a relaxation followed by a contraction upon cessation of stimulation. SP contracted the taenia while VIP caused a relaxation. The enkephalins raised the resting tension slightly while somatostatin had no effect. These observations are compatible with a role for SP as an excitatory neurotransmitter and for VIP as an inhibitory one, and with the view that both SP neurones and VIP neurones act as motor neurones. In preparations contracted by SP the electrically induced contractions were reduced in amplitude while the electrically induced relaxations seen after adrenergic and cholinergic blockade were enhanced in amplitude. In preparations relaxed by VIP there was an increased contractile response to electrical stimulation, while in the atropine + guanethidine-treated preparation the electrically induce relaxations were reduced in amplitude. The enkephalins reduced the contractile response to electrical stimulation, while somatostatin induced a very small reduction in the amplitude of such responses. These observations suggest that SP neurones and VIP neurones may play additional roles as interneurones. Somatostatin neurones probably act as interneurones. Enkephalin-containing fibres may serve to modify the release of transmitter from other nerves in the smooth muscle, perhaps through axo-axonal arrangements. Alternatively, the enkephalin nerve fibres in the smooth muscle are afferent elements involved in mediating sensory impulses to the myenteric plexus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236246
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Hepatocyte differentiation during early fetal development in the rat (1981)
    Springer
    Cell & tissue research 215 (1981), S. 133-142 
    Details
    ISSN: 1432-0878
    Keywords: Rat fetus ; Hepatocyte differentiation ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Rat hepatocyte differentiation between day 12 and 19 of fetal life was studied by electron microscopy. The cytoplasmic structures involved in synthetic and secretory function, i.e., rough endoplasmic reticulum and Golgi apparatus, appear to be the first to differentiate, and their development is probably related to the secretion of different kinds of plasma proteins. The cytoplasmic organelles involved in other hepatic functions develop later: lysosomes from day 15, peroxysomes, glycogen rosettes and smooth endoplasmic reticulum still later. However, the morphological differentiation of bile canaliculi begins from day 12.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236254
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    The hypothalamic magnocellular system in the domestic fowl (1981)
    Springer
    Cell & tissue research 215 (1981), S. 113-131 
    Details
    ISSN: 1432-0878
    Keywords: Hypothalamus ; Neurosecretory cells ; Domestic fowl ; Golgi study ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the rostral hypothalamus of the domestic fowl, the magnocellular neurosecretory nuclei show a peculiar differentiation. Golgi studies of the supraoptic and paraventricular nuclei of the fowl reveal at least two major cell types: 1) large multipolar neurons, and 2) small interneurons. Golgi impregnations provide a detailed cytoarchitectural picture of the large-sized cells; the latter may well correspond to the neurosecretory cells demonstrated in the same regions by selective staining, and immunocytochemical and electron microscopical techniques. Electron microscopically, neuronal perikarya are observed to contain variable amounts of neurosecretory granules (100–200 nm in diameter; mean diameter of 160 nm) scattered throughout the cytoplasm. The diameters of these granules do not differ statistically in the two principal nuclear areas examined. The perikarya of these neurons display only a few axosomatic synapses containing electron-lucent and dense-cored vesicles (70–90 nm in diameter). Numerous nerve terminals of this type also end on the dendritic ramifications in the surrounding neuropil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00236253
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Input and output synapses on identified motor neurones of a locust revealed by the intracellular injection of horseradish peroxidase (1981)
    Springer
    Cell & tissue research 215 (1981), S. 325-332 
    Details
    ISSN: 1432-0878
    Keywords: Horseradish peroxidase ; Locust ; Motor neurone ; Synapse ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Physiologically characterised motor neurones in the thoracic ganglia of the locust were injected with horseradish peroxidase in order that the spatial relationship between their input and output synapses could be observed with the electron microscope. A modification in the development procedure for the peroxidase ensured that the internal fine structure of the stained neurones was not obscured by the diaminobenzidine reaction product. Input and output synapses may occur within 1 μm of each other on the neuropilar processes of the motor neurones. This supports physiological evidence that motor neurones may be involved in local circuit interactions within the thoracic ganglia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239118
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Differentiation and transdifferentiation of adrenal chromaffin cells of the guinea-pig (1981)
    Springer
    Cell & tissue research 215 (1981), S. 341-367 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal chromaffin cells ; Plasticity ; Eye chamber transplants ; Ultrastructure ; Catecholamine biochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Autografts of adrenal chromaffin cells from adult guinea pigs to the anterior chamber of the eye were studied electron microscopically and both histo-and biochemically 4, 8 and 12 weeks after transplantation. Transplanted chromaffin cells resembled in many respects their in-situcounterparts: they stored varying amounts of granular vesicles, which were reduced in diameter, but displayed mostly cores of low or medium electron densities suggesting predominant storage of a secondary amine. Concomitant biochemical determinations of catecholamines (CA) and phenylethanolamine N-methyltransferase (PNMT) activity revealed a distinct reduction of total CA and PNMT activity, but no change in the proportion of adrenaline (A) to noradrenaline (NA) after 4 weeks. However, an increase of NA and almost equal amounts of A and NA were found after 8 weeks. CA-histofluorescence and electron microscopy revealed that axon-like processes with varicosities extend from chromaffin cells and contain the large “chromaffin” vesicles (100–200 nm in diameter) in addition to small clear and dense-cored vesicles (40–80 nm in diameter). Processes of chromaffin cells grew in all directions over the host iris and were also found in close proximity to smooth muscle cells the sympathetic nerve supply of which had been cut by removing the superior cervical ganglion. Administration of 5-and 6-hydroxydopamine (OHDA) resulted in characteristic labeling and ultramorphological changes in axons, but caused alterations in chromaffin cell bodies only 8 weeks after transplantation. Transplanted chromaffin cells became reinnervated by nerve fibres that are considered to be cholinergic fibres derived from the ciliary ganglion. Transplanted chromaffin cells also exhibited synapse-like contacts with each other. The present study shows that chromaffin cells from adult guinea pigs transplanted to the anterior chamber of the eye retain a large number of differentiated properties. Formation of axon-like processes by these cells indicates that the anterior chamber of the eye favours transdifferentiation, as does tissue culture (Unsicker et al. 1978a), eliciting a cell type that displays features of both a sympathetic neurone and a SIF-cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239120
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Effect of disulfiram on the ultrastructure of the peptidergic and aminergic cells in the pars intercerebralis of Galleria mellonella (Lepidoptera) (1981)
    Springer
    Cell & tissue research 215 (1981), S. 417-424 
    Details
    ISSN: 1432-0878
    Keywords: Galleria ; Neurosecretory cells ; Pars intercerebralis ; Disulfiram ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Injection of disulfiram, a specific inhibitor of noradrenaline synthesis, evokes changes in two different types of neurons in the brain of Galleria mellonella: neurones containing dense-core vesicles (60–80 nm) and peptidergic cells containing 180–200 nm neurosecretory granules. The lowering of the electron density of the dense-core vesicles of 60–80 nm seems to be directly connected with disulfiram administration, while the decrease of the amount of neurosecretory material in the neurosecretory cells of type I seems to be a secondary effect of the drug injection. The participation of noradrenaline in the regulation of the secretory activity of type I peptidergic neurosecretory cells of the pars intercerebralis is postulated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239124
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Ultrastructural studies on oogenesis in symphyla (1981)
    Springer
    Cell & tissue research 215 (1981), S. 431-436 
    Details
    ISSN: 1432-0878
    Keywords: Oogenesis ; Cortical granules ; Chorion ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the oocytes of Hanseniella nivea, cortical granules are formed in the peripheral ooplasm during late stages of oogenesis. Single Golgi elements are involved in the process. Concurrent with the formation of cortical granules is the appearance of a chorion on the oocyte surface. Precursors of this envelope are most likely synthesized by follicle cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00239126
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Effects of pimozide on the ultrastructure of the pars intermedia in the rat (1981)
    Springer
    Cell & tissue research 217 (1981), S. 397-403 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary gland ; Rat ; MSH-cells ; Pimozide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of pimozide, a dopamine receptor-blocking agent, were studied in the pars intermedia of the rat. The animals received 100 μg/100 g pimozide daily for 2, 5, 10, 15, and 20 days. Pimozide induces ultrastructural changes after 5 days of treatment. About 50% of the MSH-cells display characteristics of stimulation. Their cytoplasm is partially or totally depleted of secretory granules. The rough endoplasmic reticulum displays a network of interconnecting cisternae and ribbon-like structures. The well-developed Golgi complexes exhibit numerous dilatations of their cisternae, which contain electron-dense material. The nerve endings are not altered. Twenty days after treatment, the above-described changes have not decreased in magnitude. The present findings suggest that pimozide stimulates the mechanism of synthesis and release in some MSH-cells, most probably the elements underlying an inhibitory dopaminergic control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233589
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Ultrastructure of spermiogenesis in Liza aurata Risso, 1810 (Teleostei, Mugilidae) (1981)
    Springer
    Cell & tissue research 217 (1981), S. 415-424 
    Details
    ISSN: 1432-0878
    Keywords: Secondary spermatocytes ; Spermatids ; Spermatozoa ; Marine teleost ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sequential cytological events in late spermatogenesis of Liza aurata were studied from the stage secondary spermatocytes to that of mature spermatozoa. Spermiogenesis involves preparatory morphological events followed by conspicuous modifications such as intracellular movements (diplosome and mitochondrion migration, spermatid lengthening, nuclear rotation) and structural changes (dense chromatin granules, increase in size of mitochondria, loss of cytoplasm). Mature spermatozoa, with a round nucleus and a pseudo-midpiece are of a primitive type, even compared with spermatozoa of other teleosts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233591
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Ultrastructural study of the postembryonic development of the neural lamella of Galleria mellonella L. (Lepidoptera) (1981)
    Springer
    Cell & tissue research 217 (1981), S. 425-433 
    Details
    ISSN: 1432-0878
    Keywords: Lepidoptera ; Neural lamella ; Postembryonic development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neural lamella encapsulating the brain of the wax moth Galleria mellonella develops from a very thin (80–120 nm) layer in the first larval instar, resembling the basal lamina, to a thick (1–4 μm) sheath composed of two zones in the seventh (last) instar. After its breakdown at the time of larval-pupal ecdysis the neural lamella is reconstructed in the pupa, 2–3 days before pupaladult ecdysis. The cells of the perineurium seem to be responsible for the formation of the neural lamella, both in the larva and pupa, even though its ultrastructure differs at these stages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233592
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Isolation and primary culture of adult human hepatocytes (1981)
    Springer
    Cell & tissue research 218 (1981), S. 13-21 
    Details
    ISSN: 1432-0878
    Keywords: Human ; Isolated hepatocytes ; Primary culture ; Albumin synthesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Biopsy tissue of adult human liver was gently dissociated with collagenase followed by Dispase. By repeated low g centrifugation, a large number of almost pure, viable hepatocytes was obtained. This is the first report of a successful procedure for obtaining adult human hepatocytes for study in tissue culture. The isolated cells have the typical morphology of liver parenchyma, and these characteristics persist throughout the period of culturing. Evidence of their function is indicated by albumin synthesis. This procedure is now being used to study human hepatocyte functions in vitro and the effects of a variety of agents including carcinogens and viruses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210087
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Ultrastructure of the rat thymus: The micro-environment of T-lymphocyte maturation (1981)
    Springer
    Cell & tissue research 218 (1981), S. 279-292 
    Details
    ISSN: 1432-0878
    Keywords: Thymus micro-environment (rat) ; Epithelial cells ; Macrophages ; Interdigitating cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the micro-environment of the fully functional rat thymus was studied. The thymus consists of two discrete compartments, viz., an epithelial and a mesenchymal compartment. Thymus fibroblasts/fibrocytes, mast cells and granulocytes, are restricted to the mesenchymal compartment. The thymocyte maturation process seems to occur in the epithelial compartment in a network of reticular epithelial cells. The cortex is finely meshed and filled with proliferating thymocytes and some scattered macrophages. Moreover, in the medulla vacuolated epithelial cells form part of a loosely meshed reticulum which is filled with thymocytes and interdigitating cells (IDCs). IDCs frequently contain Birbeck granules and appear to be phagocytic. Together with macrophages, they probably enter the thymus, predominantly in the cortico-medullary region, and cross the separating wall between the two compartments. Some functional aspects of the non-lymphoid cells and in particular the IDCs, which form the micro-environment of the thymus, are discussed with respect to T-cell development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210344
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Glycoprotein gonadotropin in the plasma and its cellular origin in the adenohypophysis of sham-operated and ovariectomized rainbow trout, salmo gairdneri (1981)
    Springer
    Cell & tissue research 218 (1981), S. 439-448 
    Details
    ISSN: 1432-0878
    Keywords: Pituitary salmonids ; GTH-cells ; Ultrastructure ; Ovariectomy ; Radioimmunoassay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Among the cells of the pituitary generally believed to produce glycoprotein gonadotropin (GTH) five forms were distinguished, based on the amount and the diameter of granules and globules and the appearance of the rough endoplasmic reticulum. In sham-operated trout so-called “globular” cells predominated, whereas after ovariectomy these were replaced by so-called “cisternal” cells, suggesting that both belong to one GTH-cell type. In addition, ovariectomy caused a strong increase in plasma GTH-levels. This indicates that the transition from globular to cisternal cells is accompanied by extrusion of GTH, and thus points to a storage of GTH in the granules and globules. It is argued that one of the five forms has the morphological characteristics of thyrotropic cells and may not produce glycoprotein GTH.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210356
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Ultrastructure of muscle fibres in head and axial muscles of the perch (Perca fluviatilis L.) (1981)
    Springer
    Cell & tissue research 219 (1981), S. 111-131 
    Details
    ISSN: 1432-0878
    Keywords: Fish ; muscle fibre types ; Ultrastructure ; Morphometry ; Function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary White, pink, red and deep red fibres, selected from a head muscle and from axial muscles of the perch, show significant differences in actin filament length, Z line thickness, Z line lattice space, myofibril girth, the percentages volume occupied by T system and terminal cisternae of the SR, and in the degree of T system SR contact per sarcomere. In both muscles the degree of T system SR contact decreases in the order: white, pink, red, deep red, which suggests a decrease of contraction velocity in the same order. The position of the T system (at the Z line or at the AI junction) is related to the actin filament length. The actin filaments in the red fibres are appreciably longer than in the white, which suggests that the sarcomeres of the red fibres have a broader length-tension curve. The Z line thickness is positively correlated with the actin filament length and, in the white and the red fibres, negatively with the degree of sarcomere shortening. Thicker Z lines are suggested to allow greater sarcomere sizes (length or girth). The percentage volume occupied by mitochondria varies independently of the extent of membrane systems. The ultrastructural characteristics of the fibre types are in agreement with the functional roles as reported in literature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210022
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Ultrastructure of the pineal organ of the killifish, Fundulus heteroclitus, with special reference to the secretory function (1981)
    Springer
    Cell & tissue research 219 (1981), S. 355-369 
    Details
    ISSN: 1432-0878
    Keywords: Pineal organ ; Secretory function ; Photosensory function ; Ultrastructure ; Killifish, Fundulus heteroclitus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pineal organ of the killifish, Fundulus heteroclitus, was investigated by electron microscopy under experimental conditions; its general and characteristic features are discussed with respect to the photosensory and secretory function. The strongly convoluted pineal epithelium is usually composed of photoreceptor, ganglion and supporting cells. In addition to the well-differentiated photosensory apparatus, the photoreceptor cell contains presumably immature dense-cored vesicles (140–220 nm in diameter) associated with a well-developed granular endoplasmic reticulum in the perinuclear region and the basal process. These dense-cored vesicles appear rather prominent in fish subjected to darkness. The ganglion cell shows the typical features of a nerve cell; granular endoplasmic reticulum, polysomes, mitochondria and Golgi apparatus are scattered in the electron-lucent cytoplasm around the spherical or oval nucleus. The dendrites of these cells divide into smaller branches and form many sensory synapses with the photoreceptor basal processes. Lipid droplets appear exclusively in the supporting cell, which also contains well-developed granular endoplasmic reticulum and Golgi apparatus. Cytoplasmic protrusions filled with compact dense-cored vesicles (90–220 nm in diameter) are found in dark-adapted fish. The origin of these cytoplasmic protrusions, however, remains unresolved. Thus, the pineal organ of the killifish contains two types of dense-cored vesicles which appear predominantly in darkness. The ultrastructural results suggest that the pineal organ of fish functions not only as a photoreceptor but also as a secretory organ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210154
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    The fine structure of the neural lobe of the mouse after transplantation under the kidney capsule (1981)
    Springer
    Cell & tissue research 219 (1981), S. 417-423 
    Details
    ISSN: 1432-0878
    Keywords: Neurohypophysis (Mouse) ; Transplantation ; Pituicytes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The neurohypophysis of donor mice was implanted under the renal capsule of the recipients. The pituicytes survived while the neurosecretory axons disappeared. The ultrastructure of the glial cells was observed seven and nine weeks after transplantation. There were no signs of phagocytotic activity although remnants of axons were still present at seven weeks. The numerous processes of the pituicytes form a network with intercellular spaces wide in younger and narrower in older implants. The cells are connected by desmosomes and gap junctions. Pituicytes as well as blood vessels preserve their organotypic appearance. The transplant thus represents an experimental model for investigations on pituicytes in vivo in the absence of neurosecretory axons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210159
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Development of the bovine acrosome (1981)
    Springer
    Cell & tissue research 219 (1981), S. 511-524 
    Details
    ISSN: 1432-0878
    Keywords: Acrosome, bovine ; Acrosomal development ; Acrosomal glycoproteins ; Ultrastructure ; Cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the present study the development of the bovine acrosome was investigated using conventional electron-microscopical techniques as well as the phosphotungstic-acid (PTA) technique (Rambourg 1967) including enzymatic digestion experiments. As in other species and in accordance with previous light-microscopical studies (Clermont and Leblond 1955) four phases of acrosomal differentiation can be discerned: the Golgi-phase, cap-phase, acrosome-phase, and maturation-phase. In the bull no internal pattern of the acrosomal content can be observed, either with conventional uranyl acetate-lead citrate staining or with the PTA-techniques. Our results support the observation in other species (Fawcett et al. 1971) that no intrinsic polymerization or crystallization process of the acrosomal content is responsible for acrosomal shaping. Some of our results suggest the influence of external forces on acrosomal development in the bull. During the cap-phase and the acrosome-phase accumulations of smooth endoplasmic reticulum and a layer of fine filaments can be observed in the Sertoli-cell cytoplasm, immediately adjacent to the developing acrosome. A temporary influence of these structures on acrosomal development seems possible. The PTA-positive staining of the developing bovine acrosome is probably due to the presence of acrosomal glycoproteins; however, our results do not exclude the possibility that molecules other than glycoproteins contribute to the positive PTA-staining of the developing acrosome.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209990
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    Electron-microscopic studies on the relationship between the frequency of parathyroid storage granules and serum calcium levels in the rat (1981)
    Springer
    Cell & tissue research 219 (1981), S. 457-467 
    Details
    ISSN: 1432-0878
    Keywords: Parathyroid (Rat) ; Storage granules ; Serum calcium level ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the rat parathyroid, the mean number of storage granules (NSG) per chief cell has been electron-microscopically studied and correlated with the mean serum calcium level (SCL). In animals given 4% CaCl2 plus vitamin D2 for 3 days, SCL is significantly elevated and NSG is increased. When these animals are injected with 2% EDTA, SCL is lowered to 8 mg/dl, but NSG is not affected; in those injected with 4% EDTA, however, SCL declines to a minimum (5.8 mg/dl) after 30 min, and NSG is also decreased. Control SCL are 8.9 mg/dl. These results indicate that storage granules may not be released until SCL is depressed to a certain level. In rats 3 weeks after castration, the chief cells show hyperplastic changes and SCL is at a low concentration (8.0 mg/dl). NSG, however, remains almost within control limits. Castrated animals injected with 4% EDTA show a hypocalcemia and a decrease in NSG, but NSG gradually recovers over a period of 6h. These data suggest that storage granules can be produced even under lower calcium concentrations. It is concluded that storage granules may be constantly produced and stored, and are released only as an emergency supply of hormone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00209986
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Ultrastructural study of the sinus gland of the crab, Cardisoma carnifex (1981)
    Springer
    Cell & tissue research 220 (1981), S. 293-312 
    Details
    ISSN: 1432-0878
    Keywords: Neurosecretion ; Sinus gland ; Ultrastructure ; Crustacea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The sinus gland of Cardisoma carnifex was examined by light and transmission electron microscopy. This neurohemal organ is composed primarily of enlarged, branching axon terminals with numerous finger-like projections, which act as storage and release sites for neurohormones that are assumed to be contained in membrane-bound, electron-dense neurosecretory granules. Also present in the sinus gland are glial cells with cytoplasmic processes which form elaborate wrappings around neurosecretory terminals, and an acellular fibrillar lining of the branching blood sinus. Six types of neurosecretory terminals are identified on the basis of granule size, granule density, and density of the axoplasmic matrix. Images supporting the hypothesis of release of neurosecretory material by exocytosis from terminals abutting the blood sinus lining are found. Large multilamellate bodies appear in terminals depleted of neurosecretory granules and may be involved in the recycling of granule membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210510
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Morphologic development of neonatal rat pinealocytes in monolayer culture (1981)
    Springer
    Cell & tissue research 220 (1981), S. 337-347 
    Details
    ISSN: 1432-0878
    Keywords: Pineal ; Monolayer culture ; Development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological development of pinealocytes maintained in monolayer culture, without the neural and humoral effects present in the developing rat has been studied and compared with the development that occurs in vivo. Pinealocytes in 5 day cultures contained organelles that were similar to those present in the pineals of intact 5 day old rats. However, light and dark cells were not noted in culture, and the cultured cells did not have the dense granules noted in vivo. As pinealocytes developed in culture, cytoplasmic processes increased in length and number. By 21 days of culture age, synaptic ribbons were found to have decreased in number, the difference between light cell and dark cell cytoplasm had become more prominent, and dense-cored vesicles had become more numerous, just as in the developing gland in vivo. These results suggest that the complex neural and humoral factors impinging upon the developing neonatal pineal in the intact animal may not be necessary for some aspects of its ultrastructural differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00210513
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...