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  • Ultrastructure  (202)
  • Chromatographie, Dünnschicht  (39)
  • Immunocytochemistry  (34)
  • Auxin  (30)
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  • 1
    Digitale Medien
    Digitale Medien
    Coquille de l'oeuf de caille: Étude ultrastructurale et cristallographique (1978)
    Springer
    Calcified tissue international 25 (1978), S. 145-159 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Bird egg shell ; Ultrastructure ; Calcification ; Electron diffraction ; Microanalysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The egg-shell of Japanese quail was studied by several techniques. Semithin sections (1μm thick) of non-decalcified shell were observed by normal and polarized light microscopy. Thin sections of non-decalcified shell, examined by transmission electron microscopy, permitted us to observe the forms and dimensions of crystals of calcite within different layers of the shell: mammilary layer, layer of cones, palissade layer and surface crystal layer. There appears to be two distinct zones in the layer of cones as well as in the superficial crystal layer. Electron microdiffraction revealed the orientation of calcite crystals in the columns. Some crystal defects (twins?) were described and the possibility of their artefactual formation during ultramicrotomy is discussed. Localization of Ca, Mg, P and S were made by X-ray microanalysis of semithin sections. This technique shows that shell membranes, and chiefly the true cuticle, are also mineralized but, in these layers, minerals are not crystallized. Otherwise the distribution of Mg is not uniform throughout the shell thickness; it is less concentrated in the external zone of the layer of cones. These results together with observation of developing shells by scanning electron microscopy allowed us to propose a scheme for shell organization of the quail egg. This organization was related with decalcification which occurs during hatching.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02010763
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Ultrastructural and microanalytical aspects of developing osteodentin in rat incisors (1977)
    Springer
    Calcified tissue international 24 (1977), S. 215-222 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Mineralization ; Osteodentin ; Intracellular ; Ultrastructure ; Microanalysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary Newly formed osteodentin obtained from the anterior extremities of fetal or young rat incisors was observed by means of electron microscopy and electron probe X-ray microanalysis. Cells related to osteodentin formation frequently showed membrane bound intracellular bodies containing varying amounts of fine, needle-shaped crystals, which were identified as apatite. The intracellular clusters of apatite crystals were extruded from the cells through membrane fusion or cellular degeneration. These extracellular clusters seemed to be gradually incorporated into the mineralizing collagenous matrix, which developed around them. Frequent occurrence of dense, dotshaped or filamentous profiles suggested that the dense bodies seen in the perinuclear regions or in the Golgi area were the sites of crystal formation. Energy dispersive X-ray point analysis showed that the intracellular or extracellular apatite clusters contained sulfur in a concentration higher than was present in the mineralizing collagenous matrix. Furthermore, wave dispersive X-ray line analysis showed that the concentration of sulfur was higher in the osteodentin matrix than in the dentin matrix. The sulfur detected is presumed to be contained in acid mucopolysaccharides, which were distributed more heavily in the osteodentin matrix than in the dentin matrix. On the basis of these data, it was concluded that the unique chemical and structural characteristics of the osteodentin result primarily from the incorporation of apatite clusters of intracellular origin and associated acid mucopolysaccharides.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02223319
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Étude en microscopie électronique et par cytophotométrie à balayage de la structure et de la distribution de la chromatine dans les noyaux des cellules cartilagineuses deTriturus cristatus âgés au cours de la régénération (1978)
    Springer
    Development genes and evolution 184 (1978), S. 195-211 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Ultrastructure ; Scanning cytophotometry ; Chromatin ; Chondrocytes ; Regeneration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Résumé Les cellules cartilagineuses des membres postérieurs deTriturus cristatus en régénération après amputation, ont été étudiées en microscopie électronique et par cytophotométrie à balayage. Nous nous sommes intéressés à la structure et à la distribution de la chromatine mais aussi à différents organites cytoplasmiques. Dans l'étude de cytophotométrie à balayage, la chromatine a été considérée à travers son constituant majeur, l'ADN, coloré par la réaction de Feulgen. Au cours de la régénération du membre, l'hétérochromatine initialement condensée, essentiellement accolée à la membrane nucléaire se décondense. Les vacuoles du cytoplasme, caractéristiques des animaux âgés par rapport aux animaux jeunes, disparaissent, les mitochondries et le reticulum endoplasmique rugueux deviennent plus abondants. Les caractéristiques nucléaires de l'activation cellulaire apparaissent précocement, précédent les modifications cytoplasmiques et conduisent à des cellules en tous points identiques aux cellules d'animaux jeunes en dehors de tout processus régénératif. Cette phase d'euchromatisation et de restructuration cytoplasmique est peut-être nécessaire à l'accroissement d'activité métabolique et à la division cellulaire qui suivent. Son déroulement peut expliquer tout au moins le ralentissement de la régénération observé chez les animaux âgés par rapport aux animaux jeunes.
    Notizen: Summary Cartilaginous cells of aged newts (Triturus cristatus) were studied during hind limb regeneration. The electron microscope was used to study the structure and distribution of chromatin in the cell nuclei, while the DNA content of the chromatin was measured by means of a scanning cytophotometer. Changes in the ultrastructure of the cytoplasm during regeneration were also studied. It was observed that the structure and distribution of chromatin in the activated cell is greatly modified. In the non-activated cell of the aged newt, the chromatin is found highly condensed and distributed peripherally close to the nuclear membrane. In contrast, in the activated cells, the chromatin is much less condensed and is distributed throughout the nucleus. Moreover, cytoplasmic vacuoles, found only in the non-activated aged cells, disappear and an increase in the mitochondria and rough endoplasmic reticulum is also observed. Changes in the nuclear structure are observed prior to the cytoplasmic modifications. It is interesting to note that the process of activation induces structural changes in the aged cells which make these cells appear to be structurally identical to the young cells. This process of rejuvenation takes 3–5 days in the newt. We suggest that these structural changes of the chromatin and cytoplasm in the aged cells are necessary to increase the metabolic activity which precedes cell division. It may also explain why regeneration takes a longer time in the aged animals than in the young ones.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848254
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    The cytoplasmic architecture of the egg cell ofSmittia spec. (Diptera, Chironomidae) (1977)
    Springer
    Development genes and evolution 183 (1977), S. 233-248 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Cytoplasmic architecture ; Ultrastructure ; Insect egg ; Pattern formation ; Yolk ; Cytoplasma-Architektur ; Ultrastruktur ; Insekten-Ei ; Musterbildung ; Dotter
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung 1. Das Ei der ZuckmückeSmittia spec. wurde licht- und elektronenmikroskopisch untersucht. Die vorliegende Arbeit beschreibt den Bau des Periplasmas und des Dotter-Endoplasma-Systems vor Bildung der Polzellen. 2. Das Periplasma, nach außen vom Oolemm und einer mehrschichtigen Eihülle begrenzt, besteht aus einer ribosomenreichen cytoplasmatischen Matrix, in die vor allem Mitochondrien und ER-Zisternen, wenig annulate lamellae und gelegentlich Golgi-Apparate eingelagert sind. Mikrotubuli wurden nur selten nachgewiesen. Öfters sind Anhäufungen einer dichten granulierten Substanz zu beobachten, die in ihrer Struktur dem Oosom-Material ähnelt. 3. Das Dotter-Endoplasma-System stellt ein Netzwerk aus Cytoplasma dar, in das Proteid-Dotterkugeln, Lipidtröpfchen sowie Glycogen-Anhäufungen eingelagert sind. Das Endoplasma, das sich zu 3–7 Plasma-Inseln erweitern kann und unmittelbar in das Periplasma übergeht, besteht wie dieses aus einer cytoplasmatischen Matrix und enthält die gleichen Zellelemente wie das Periplasma. Rosettenförmige Membran-Strukturen werden als “nuclear envelope organizing center” gedeutet. 4. Drei der sorgfältig analysierten Eier enthielten je 2 Kerne; sie lagen in Plasma-Inseln in der hinteren Eihälfte. 5. Sowohl im Periplasma wie im Dotter-Endoplasma-System sind alle Zellelemente unregelmäßig verteilt. Eine besondere Anordnung oder Zonierung ist nicht zu erkennen. 6. Die räumliche Verteilung der erfaßten Eikomponenten liefert keine Hinweise auf eine Funktion dieser Komponenten als Determinanten für die embryonale Musterbildung.
    Notizen: Summary 1. Eggs of the midgeSmittia were investigated by light microscopy and transmission electron microscopy. This paper describes elements and architecture of periplasm and yolk endoplasm before the formation of pole cells. 2. The periplasm is coated externally by the oolemma and a multilayered egg shell. The periplasm consists of a cytoplasmic matrix rich in ribosomes; it contains mitochondria and ER cisternae, some annulate lamellae and an occasional Golgi complex. Microtubuli were demonstrated only rarely. Accumulations of a dense granulated substance resembling in its structure the oosome material were frequently observed. 3. The yolk endoplasm is a cytoplasmic network embodying proteid yolk particles, lipid droplets and accumulations of glycogen. The endoplasm is continuous with the periplasm and shows the same cell constituents. It may form between 3 and 7 cytoplasmic islands free of yolk particles. Rosette-shaped membranous structures in the yolk endoplasm are interpreted as nuclear envelope organizing centres. 4. Three carefully analysed eggs contained 2 nuclei each. both nuclei were situated in the posterior egg half. 5. Periplasm and yolk endoplasm are characterized by random distribution of cell elements. No zonation or special accumulations could be recognized. 6. The spatial distribution of the egg components studied did not indicate that any of these components could function as a determinant in embryonic pattern formation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00867324
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Ultrastructure of a fertilized barnacle egg (Pollicipes polymerus) with peristaltic constrictions (1977)
    Springer
    Development genes and evolution 181 (1977), S. 333-355 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Barnacle eggs ; Constriction rings ; Microfilaments ; Ultrastructure ; Peristalsis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary 1. The egg ofPollicipes polymerus, the common intertidal gooseneck barnacle, has been studied by electron microscopy. Constriction rings, similar to the contractile rings of cleaving cells and polar lobes, move unidirectionally from the animal to the vegetal pole of newly fertilized eggs. This is referred to as peristaltic constriction. The present paper describes the fine structure of the egg during first polar body formation and peristalsis. 2. During formation of the polar body, dense bodies are produced by the Golgi and extracellular plaques are observed. Thin microfilaments (40–60 Å) are in the egg adjacent to the polar body. 3. In eggs undergoing peristalsis, the appearance of extracellular spheres, flocculent material and filaments is observed. Intracellularly large numbers of multivesiculate bodies, glycogen granules, mitochondria and protein-carbohydrate and lipid yolk bodies are seen at the level of constriction. 4. Thin microfilaments are found in the cortical area of newly-fertilized eggs exclusively in peristaltic constriction rings. Filaments are oriented primarily in a meshwork, although circumferentially-oriented filaments are also found in rings near the vegetal pole. Microvilli extend into the space created between a constriction and the elevated egg membrane. 5. A model is proposed to explain the peristalsis in this species. It is suggested that information from a pacemaker region activates peristalsis by affecting filament polymerization and orientation. One function of peristalsis may be elongation of the egg from a sphere to an ovoid, although other possibilities such as elevation of the egg membrane, segregation of the lipid yolk to the vegetal pole and predetermination of the first cleavage plane are also discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848060
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  • 6
    Digitale Medien
    Digitale Medien
    Retention of the differentiated state by larvalXenopus liver cells in primary culture (1978)
    Springer
    Development genes and evolution 185 (1978), S. 235-248 
    Details
    ISSN: 1432-041X
    Schlagwort(e): Liver ; Primary culture ; Ultrastructure ; Albumin synthesis ; Xenopus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Electron microscopic analysis of primary cultures derived from larvalXenopus liver has shown that these cells, although they form only two-dimensional aggregates, retain and presumably also develop structural characteristics typical of liver parenchyma cells, such as bile canaliculi with microvilli and epithelial junctional complexes. As judged from structural criteria, primary cultures contain 80–90% hepatocytes. In contrast to the intact tissue, primary cultures showed excessive development of microfilaments, however. Incorporation of labeled amino acids has revealed further that the capacity for protein synthesis is maintained in culture and that synthesis of liverspecific protein albumin is maintained in vitro, even in liver cultures derived from thyrostatic tadpoles. This latter result suggests that initiation of albumin synthesis in the larval liver is probably not dependent upon thyroid hormones but rather reflects the protodifferentiated state of this tissue.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00848354
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  • 7
    Digitale Medien
    Digitale Medien
    Ultrastructure, histology, and innervation of the mantle edge of the freshwater pulmonate snailsLymnaea stagnalis andBiomphalaria pfeifferi (1978)
    Springer
    Calcified tissue international 26 (1978), S. 271-282 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Shell formation ; Free nerve endings ; Ultrastructure ; Lymnaea stagnalis ; Biomphalaria pfeifferi
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The mantle edge of the freshwater pulmonate snailsLymnaea stagnalis andBiomphalaria pfeifferi was investigated with histochemical and ultrastructural methods. The mantle edge gland, which is involved in shell formation, consists of the periostracal groove and the belt. This belt appears to be composed of various regions. In the area of the periostracal groove a number of subepithelial gland cell types occur; these release their products into the groove. Between the groove cells ciliated free nerve endings terminate; the corresponding perikarya occur in the subepidermal connective tissue. Also in the posterior belt region free nerve endings were observed between the epithelial cells; in addition, a particular type of subepithelial gland cell was found in this area. The epithelial cells of this part of the belt have the ultrastructural characteristics of ion and water transporting cells; they are probably involved in calcium deposition and resorption. The possible role of the free nerve endings and of the subepithelial gland cells is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02013270
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  • 8
    Digitale Medien
    Digitale Medien
    Demonstration of enamel matrix proteins on root-analogue surfaces of rabbit permanent incisor teeth (1977)
    Springer
    Calcified tissue international 24 (1977), S. 223-229 
    Details
    ISSN: 1432-0827
    Schlagwort(e): Enamel-cementum-morphology ; Immunocytochemistry ; Biochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The continuously erupting rabbit incisor tooth is normally thought of as having an enamel covered “crown” on its labial surface and a cementum covered “root” on its lingual surface. We have examined both surfaces of continuously erupting rabbit incisor teeth taken from near term embryos by a variety of means, including transmission and scanning electron microscopy, biochemical fractionation, and immunohistochemistry. In all cases, we could detect no qualitative difference in the early extracellular matrices taken from the labial and lingual surfaces of the teeth. Both matrices were shown to be composed of dentin and enamel, although the thickness and geometry of the enamel matrix on the lingual surface was somewhat different from that on the labial surface.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02223320
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  • 9
    Digitale Medien
    Digitale Medien
    Affinity labels for auxin binding sites in corn coleoptile membranes (1977)
    Springer
    Planta 134 (1977), S. 145-149 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Affinity labels ; Auxin ; Cell membranes ; Hormone Receptors ; Receptors ; Zea mays
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two auxin analogues have been tested as affinity labels for auxin binding sites in coleoptile membranes of Zea mays L. Reacting the membranes at pH 8–9 with the diazonium salt of CAPA (2-chloro-4-aminophenoxyacetic acid) reduces their subsequent ability to bind NAA(1-naphthylacetic acid). Diazo-Chloramben (2,5-dichloro-3-aminobenzoic acid) is also effective in inhibiting NAA binding capacity and this inhibition is largely independent of reaction pH over the range pH 6–9. Similar experiments with sulphydryl reagents have shown that reaction of the membranes with p-mercuribenzoate (PMB) strongly inhibits subsequent auxin binding activity. Prior addition of NAA protects the binding sites against the action of diazo-Chloramben or PMB when the reactions are carried out at pH 6. From these results and from other considerations, several of the amino acid residues in the binding site environment have been tentatively assigned.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384963
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  • 10
    Digitale Medien
    Digitale Medien
    Ultrastructural damage due to freezing followed by thawing in shoot meristem and leaf mesophyll cells of tall fescue (Festuca arundinacea Schreb.) (1977)
    Springer
    Planta 134 (1977), S. 159-168 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Festuca ; Frost damage ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Tillers of Festuca arundinacea Schreb. were subjected to-8°C in a bath of methylated spirits for three-quarters of an hour. They were thawed at room temperature and some material taken from the shoot apical meristem and leaf blade for electron microscopy. Similar material was taken from control plants for electron microscopy. Nine tillers subjected to-8°C and thawed subsequently failed to regrow. Nine control tillers regrew. All the treated meristem cells and about half the treated leaf mesophyll cells were extensively altered. Their nuclei were contracted, organelles were swollen or partly disrupted, plasmalemma and nuclear membranes were broken or absent and vacuoles were sometimes disrupted. Strongly osmiophilic material accumulated in the vicinity of membranes. About half the leaf mesophyll cells differed from the control mesophyll cells only in having more spherosomes and narrower thylakoids. Parallels with other ultrastructural studies of stress damage and the indications the results give of possible primary damaging events are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384966
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  • 11
    Digitale Medien
    Digitale Medien
    Growth of Avena coleoptiles and pH drop of protoplast suspensions induced by chlorinated indoleacetic acids (1978)
    Springer
    Planta 140 (1978), S. 89-92 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Avena ; Helianthus ; pH drop ; Pisum ; Protoplast suspension
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Several indoleacetic acids, substituted in the benzene ring, were compared in the Avena straight growth bioassay. 4-Chloroindoleacetic acid, a naturally occurring plant hormone, is one of the strongest hormones in this bioassay. With an optimum at 10-6 mol l-1, it is more active than indoleacetic acid, 2,4-dichlorphenoxyacetic acid and naphthaleneacetic acid. 5-Chloro- and 6-chloroindoleacetic acids are very strong auxins as well. Other derivatives tested have a lower activity. 5,7-Dichloro- and 5-hydroxyindoleacetic acids have very low auxin activity at 10-4 mol l-1 and may be anti-auxins. Some of the derivatives were compared for their effect on pH decline in stem protoplast suspensions of Helianthus annuus L. and Pisum sativum L. The change of pH occurs without a lag period or with only a very short one. Derivatives which are very active in the Avena straight growth assay cause a larger pH decline than indoleacetic acid, while inactive derivatives cause effectively no pH decline.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00389385
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  • 12
    Digitale Medien
    Digitale Medien
    Early time course and specificity of auxin effects on turgor movement of the bean pulvinus (1978)
    Springer
    Planta 140 (1978), S. 107-109 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Leaf movement ; Phaseolus ; Pulvinus ; Turgor movement
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Auxin application to the upper side of the pulvinus of primary leaves of Phaseolus vulgaris L. promoted bending away from the place of application. The effect had a latency of less than 20 min and was specifically induced by substances known as active auxins in growth tests (indoleacetic and 1-naphthaleneacetic acid) but not by inactive auxin analogs (2-naphthaleneacetic, 3-indolepropionic and benzoic acid); 2,4-dichlorophenoxyacetic acid, and L-(-)-2,4-dichlorophenoxyisopropionic acid were of intermediate activity. Auxin-promoted bending was reversible and presumably caused by turgor increase in the treated cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384908
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  • 13
    Digitale Medien
    Digitale Medien
    Continuous measurement of initial curvature of maize coleoptiles induced by lateral auxin application (1978)
    Springer
    Planta 140 (1978), S. 201-211 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Cell elongation ; Coleoptiles ; Fusicoccin ; Zea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To analyze early effects of auxin application, an apparatus was developed which continuously and simultaneously registered the curvature of 10 individual maize (Zea mays L.) coleoptiles. Resolution was less than 5 μm over a range of ±0.5 mm. The data were evaluated and plotted via paper tape and Hewlett-Packard-computer. Unilateral application of 3×10-5 M indoleacetic acid (IAA) resulted in a transient inhibition of growth on the side of application for ca. 10 min (Phase I), followed by a strong stimulation (Phase II). The phytotoxin fusicoccin (FC) caused an immediate stimulation of elongation. The initial negative reaction of Phase I is auxin-specific. Only active auxins such as IAA and 1-naphtaleneacetic acid produced this initial inhibition; chemical analogs-inhibitory or neutral in long-term growth tests, e.g. phenylacetic acid-did not show any significant effects on Phase I. When the coleoptiles were symmetrically preloaded with different levels of auxin, only a large step-up of subsequent unilateral auxin application resulted in a negative phase I; a small step-up led to an immediate positive reaction. The results are discussed in context with the parallel kinetics for various other auxin-induced reactions of coleoptile cells which have already been published.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00390249
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  • 14
    Digitale Medien
    Digitale Medien
    Auxin inhibition of acid-and fusicoccin-induced elongation in lentil roots (1977)
    Springer
    Planta 136 (1977), S. 97-102 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Acid growth ; Auxin ; Ethylene ; Fusicoccin ; Growth inhibition ; Lens ; Root growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Both acid pH (4.0) and fusicoccin (FC) strongly stimulate root elongation in intact lentil (Lens culinaris Med.) seedlings. FC-induced elongation is apparently mediated by FC-enhanced H+ secretion since the toxin induces massive secretion of H+ in these roots after a latent period of less than 5 min. Auxin (indole-3-acetic acid) strongly inhibits elongation in control roots as well as acid-induced and FC-induced root elongation. Treatment of apical root segments with auxin causes only a slight apparent uptake of H+ and has no inhibitory effect on FC-induced H+ secretion, whether the hormone is given before or after the toxin. Auxin induces ethylene production in excised roots of lentil but the latent period is at least 30 min while inhibition of root elongation by IAA is maximal within 30 min. It is concluded that the inhibitory action of auxin on acid-and fusicoccin-induced root elongation is a direct effect, independent of auxin-induced ethylene production or auxin-mediated modification of cell-wall pH.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00396184
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  • 15
    Digitale Medien
    Digitale Medien
    Synergistic effect of gibberellic acid and indole-3-acetic acid on rooting in stem cuttings of Abelmoschus esculentus Moench (1978)
    Springer
    Planta 138 (1978), S. 111-112 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Abelmoschus ; Auxin ; Gibberellin ; Root formation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Indole-3-acetic acid (IAA) and gibberellic acid (GA3) enhanced the formation of roots on the stem cuttings of Abelmoschus esculentus. The effect increased considerably when both IAA and GA3 were applied together.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00392926
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  • 16
    Digitale Medien
    Digitale Medien
    Asymbiotic association of Rhizobium with pea epicotyls treated with a plant hormone (1978)
    Springer
    Planta 138 (1978), S. 107-110 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Nitrogen fixation (asymbiotic) ; Pisum ; Rhizobium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Treatment of epicotyls of dark-grown pea (Pisum sativum L.) seedlings with indole-3-acetic acid causes swelling of the tissue. Application of Rhizobium to the cut surface of the swollen tissue results in the development of an “infection”. The infection spreads in the cortical cells and proceeds 2–3 mm deep into the stem within 3–4 days. An acetylene reduction assay used for detecting nitrogen-fixation capacity of the infected tissue was negative at 10% [O2]; however, if [O2] was reduced to below 1%, some activity could be detected. Ultrastructural observations indicate that the cytoplasmic contents of the infected cells are destroyed and no membrane structure around the bacteria is formed during this infection. Rhizobium does not appear to have developed any symbiotic relationship with the host. Failure to develop symbiosis appears to result in a parasitic or saprophytic association and the nitrogen fixed under such conditions may not be of any use to the plant.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00392925
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  • 17
    Digitale Medien
    Digitale Medien
    The influence of growth regulators absorbed by the root on sex expression in hemp plants (1978)
    Springer
    Planta 138 (1978), S. 181-184 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Abscisic acid ; Auxin ; Cannabis ; Cytokinin ; Flowers (sex) ; Gibberellin ; Sex expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Application, through the root system, of growth regulators to hemp (Cannabis sativa L.) plants having 2–3 pairs of visible leaves caused pronounced shifts of sex expression in the adult individuals. Treatment with gibberellic acid (25 mg/l) resulted in more than 80% of the plants being male, i.e. having staminate flowers (controls, ca. 30%). Treatment with 6-benzylaminopurine and with indole-3-acetic acid (in either case, 15 mg/l) resulted in all plants being either female (pistillate flowers) or intersexes (bisexual flowers); treatment with abscisic acid (10 mg/l) had a similar but somewhat less pronounced effect.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00391176
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  • 18
    Digitale Medien
    Digitale Medien
    Ethylene and adventitious root formation in hypocotyl segments of etiolated mung-bean (Vigna radiata (L.) Wilczek) seedlings (1978)
    Springer
    Planta 138 (1978), S. 193-197 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Ethylene ; Root formation ; Vigna
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Rooting responses and ethylene production by hypocotyl cuttings from etiolated mung-bean seedlings treated with the auxins α-naphthaleneacetic acid, γ-(indole-3)-n-butyric acid (IBA) and 2,4,5-trichloro-phenoxypropionic acid were determined. There was no relationship between the abilities of the auxins to induce root formation and their capacities for inducing ethylene production. Studies with mixtures of 3-indoleacetic acid, a poor stimulator of rooting but an effective inducer of ethylene production, and IBA, an effective rooting stimulator but a poor inducer of ethylene production, exposure of cuttings to ethylene or (2-chloroethyl) phosphonic acid (Ethephon), hypobaric storage (150 mb) of treated cuttings, and exposure of auxin-treated cuttings to 7% CO2 also indicated that ethylene is not directly involved in initiation of adventitious roots in this plant material.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00386810
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  • 19
    Digitale Medien
    Digitale Medien
    3-O-Methyl glucose uptake stimulation by auxin and by fusicoccin in plant materials and its relationships with proton extrusion (1978)
    Springer
    Planta 138 (1978), S. 249-256 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Fusicoccin ; Glucose transport ; Proton flux ; Roots ; Zea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Auxin and fusicoccin (FC) stimulate the active uptake of 3-O-methyl glucose (3-O-MG) in those materials in which they have been shown to activate an electrogenic proton extrusion (Pisum sativum L. stems, Zea mays L. coleoptiles and roots). In maize roots the curve relating 3-O-MG influx to external concentrations indicated that the values of the apparent Km increase in the 3-O-MG concentration range between 2×10-5 mol l-1 and 2×10-2 mol l-1. FC did not alter the Km values and its stimulating effect was nearly constant at all 3-O-MG concentrations tested. Basal and FC-induced uptake of 3-O-MG appeared associated with a transient proton influx suggesting that also in maize roots a sugar-proton contransport occurs. Diethyl stilbestrol, which inhibits proton extrusion, inhibited also basal and FC-induced 3-O-MG uptake. The data support the view that the stimulation by FC of 3-O-MG uptake is closely related to that of proton extrusion. The stimulation by FC of 3-O-MG uptake cannot be replaced by increasing extracellular proton concentration, nor may be explained only by the FC-induced hyperpolarization of transmembrane potential difference. The hypothesis is proposed that the effect of FC on 3-O-MG uptake depends on an increase of cytoplasmic pH, following the activation of the proton extruding system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00386819
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  • 20
    Digitale Medien
    Digitale Medien
    Phytochrome photoreversibility: Empirical test of the hypothesis that it varies as a consequence of pigment compartmentation (1978)
    Springer
    Planta 141 (1978), S. 129-134 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Avena ; Immunocytochemistry ; Phytochrome
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Phytochrome of oat (Avena sativa L., cv. Garry) coleoptile cells in the red-light-absorbing form, Pr, is diffusely distributed while after conversion to the far-red-light-absorbing form, Pfr, it is observed only in very small areas within the cell. Comparison of phytochrome photoversibility measurements to the distribution of the pigment within the cell indicates that the spectral assay is not influenced by the observed compartmentalization of the chromoprotein. However, the observed compartmentalization of phytochrome is correlated with a loss in spectrophotometrically detectable Pr.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00387878
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  • 21
    Digitale Medien
    Digitale Medien
    Auxin gradient along the root of the maize seedling (1978)
    Springer
    Planta 141 (1978), S. 179-181 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Maize ; Root tip ; Zea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract [5-3H]Indol-3yl-acetic acid (IAA) applied to the shoot apices of intact 6-day-old maize (Zea mays L.) plants moved into the primary root and accumulated at the root apex. IAA from the shoot could partially satisfy the requirement of the primary root for IAA for growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00387886
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  • 22
    Digitale Medien
    Digitale Medien
    Hormonal regulation of cotton ovule and fiber growth: Effects of bromodeoxyuridine, AMO-1618 and p-chlorophenoxyisobutyric acid (1978)
    Springer
    Planta 141 (1978), S. 269-272 
    Details
    ISSN: 1432-2048
    Schlagwort(e): AMO-1618 ; Antiauxin ; Auxin ; Bromodeoxyuridine ; Cell (fiber) growth ; Gibberellin ; Gossypium ; Ovules (in-vitro culture)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effects of 5-bromo-2-deoxyuridine (BUdR, thymidine analogue), AMO-1618 (2-isopropyl-4-dimethylamino-5-methylphenyl-1-piperidine carboxylate methyl chloride), a growth retardant, and p-chlorophenoxyisobutyric acid (PCIB, an antiauxin) on growth (dry weight increase) and fiber development in unfertilized cotton (Gossypium hirsutum L.) ovules grown in vitro have been studied. BUdR (5 μM) causes about 70% inhibition of fiber production, with little effect on ovule growth, if applied during the first 6 d of culture in the presence of GA3 and IAA. AMO-1618, when used with GA3 alone, causes only a small reduction in both dry weight and fiber production, but when used with IAA alone reduces both fiber production and dry weight, the effect on the latter being predominant. In the presence of both IAA and GA3, AMO-1618 causes a small decrease in fiber production but a major decrease in dry weight. PCIB completely inhibits fiber growth but has little effect on dry weight, especially when GA3 is present. These results indicate that GA3 mainly promotes ovule growth while IAA is largerly responsible for fiber growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00388342
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  • 23
    Digitale Medien
    Digitale Medien
    Effect of 2,4-dichlorophenoxyacetic acid on the structure and function of developing chloroplasts (1977)
    Springer
    Planta 137 (1977), S. 65-69 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Chlorophyll content ; Chloroplast ; Photosynthetic rate ; Raphanus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Dark-grown radish seedlings (Raphanus sativus L.) were sprayed with 10-3 mol·l-1 2,4-dichlorophenoxyacetic acid and then were exposed to a 14:10 light: dark cycle. Cotyledon samples from these seedlings and unsprayed controls were taken for electron microscopy, chlorophyll determinations, and photosynthetic rate measurements at regular intervals for 72 h. A normal development of etioplasts to chloroplasts with formation of typical grana-fret work system was observed in the control cotyledons. The chloroplasts in the 2,4-D-treated cotyledons showed changes in the organization of the grana thylakoids; these thylakoids being more appressed to each other than in the controls. The chlorophyll content of treated plants was less than that of controls but the rate of chlorophyll biosynthesis was unaffected. The photosynthetic rate/mg chlorophyll was considerably higher for treated plants suggesting that 2,4-D treatment resulted in decreased size of the photosynthetic unit.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00394437
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  • 24
    Digitale Medien
    Digitale Medien
    The stimulation of cell extension by ethylene and auxin in aquatic plants (1978)
    Springer
    Planta 144 (1978), S. 39-47 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Aquatic plants ; Auxin ; Cell elongation ; Ethylene ; Ethylene biosynthesis ; Silverions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Elongation of the shoots of three aquatic plants (Hydrocharis morsus-ranae, Regnellidium diphyllum and Ranunculus sceleratus) is stimulated by treatment with ethylene or IAA. The effects of the two hormones are additive, and experiments with an ethylene biosynthesis inhibitor and silver ions indicate that the mechanisms by which ethylene and IAA stimulate growth may be different. Hydrocharis and Ranunculus leaf discs synthesize [14C]ethylene from [14C]methionine, but no [14C]ethylene is formed by Regnellidium, suggesting the existence of an alternative pathway of ethylene biosynthesis in the fern.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00385005
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  • 25
    Digitale Medien
    Digitale Medien
    A specific radioimmunoassay for nanogram quantities of the auxin, indole-3-acetic acid (1977)
    Springer
    Planta 136 (1977), S. 173-180 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Immunoassay ; Nicotiana ; Radioimmunoassay
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We have developed a specific radioimmunoassay [RIA] for indole-3-acetic acid (IAA) in the 0.2 ng to 12 ng range which, in principle, can be extended to other indole auxins as well. Methods are presented for obtaining suitable antibody, for the RIA procedure, and for measuring IAA in methanolic extracts of plant tissues. Antibody specific for IAA was obtained from rabbits immunized with IAA bound to bovine serum albumin by formaldehyde treatment. In assays with this antibody, 2,4-dichlorophenoxyacetic acid and indoles structurally related to IAA reacted from 300- to 3000-fold less than did IAA itself. However, α-and β-naphthaleneacetic acid reacted significantly and hence interfered with the assay. Extracts of tobacco (Nicotiana tabacum L.) tissue were immunoassayed after partial purification by buffer-ether partition. Crown-gall tumor tissue, which is auxin-autotrophic, and pith tissue depleted of auxin by the diffusion method contained, respectively, 26.7 ng and 〈0.5 ng extractable IAA per gram fresh weight.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00396195
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  • 26
    Digitale Medien
    Digitale Medien
    Short-term effects of plant hormones on membrane potential and membrane permeability of dwarf maize coleoptile cells (Zea mays L. d 1) in comparison with growth responses (1977)
    Springer
    Planta 137 (1977), S. 293-298 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Calcium ions ; Cell growth ; Gibberellin ; Membrane permeability ; Membrane potential ; Zea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The membrane potential difference of dwarf maize coleoptile cells is increased by both 10-5moll-1 gibberellic acid (GA3) and indoleacetic acid (IAA) a few minutes after application. A final level is reached after 10–20 min. The membrane permeability ratio P Na:P K is altered by both hormones during the first 15 min after application, indicating a rapid effect on the membrane. Elongation growth of coleoptile segments, however, is only stimulated by IAA. The auxin-induced growth as well as the auxin effect on membrane permeability depends on the calcium ion concentration of the medium. It is concluded that IAA acts via a proton extrusion pump that is electrically balanced by a potassium ion uptake, driven by the electromotive force of the pump. The mode of action of GA3 on elongation growth is assumed to involve a process that depends on the physiologic state of the tissue and/or metabolic energy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00388165
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  • 27
    Digitale Medien
    Digitale Medien
    Lateral electrical potential following asymmetric auxin application to maize coleoptiles (1978)
    Springer
    Planta 140 (1978), S. 31-35 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Coleoptiles ; Electrical Potential ; Zea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Following asymmetric application of indoleacetic acid to maize (Zea mays L.) coleoptiles the early time course of changes in lateral electrical potential was externally monitored with static-drop electrodes. First, an early negative potential change of ca.-1 mV was measured at the surface on the side of a strong auxin application. This negative auxin effect ended after ca. 15 min and was followed by a strong and lasting auxin stimulation of a positive lateral potential up to +12 mV at the auxin-treated side. The initial auxin effect appeared to depend on the size of the step-up in auxin concentration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00389376
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  • 28
    Digitale Medien
    Digitale Medien
    Does indoleacetic acid promote growth via cell wall acidification? (1978)
    Springer
    Planta 140 (1978), S. 137-142 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Cell elongation ; Proton secretion ; Triticum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Growth of Triticum aestivum L. cv. Cappelle Desprez coleoptiles is promoted by 5.7×10−5 M indole acetic acid (IAA) as effectively in pH 3.4 buffer as in water, but IAA is not effective in the presence of buffer at pH 3.0 or 3.2 A combination of 5.7×10−5 M IAA and pH 3.4 buffer promotes growth to a greater extent than pH 3.2 buffer alone, which is optimal for acid-induced growth. IAA employed at 10−7 M is still effective at promoting growth in the presence of pH 3.4 buffer, moreover, IAA at 10−7 M interacts synergistically with the acidic buffer to promote growth. It is concluded that IAA and acid promote growth via separate mechanisms, and that IAA does not promote cell wall loosening by rendering the cell wall more acid.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384912
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  • 29
    Digitale Medien
    Digitale Medien
    Lead toxicity effects on indole-3-ylacetic acid-induced cell elongation (1978)
    Springer
    Planta 144 (1978), S. 79-84 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Cell elongation ; Lead ; Triticum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In vitro studies of IAA-induced cell elongation in Triticum aestivum have demonstrated that lead causes a large reduction in elongation. Inhibition of elongation can be reduced by increasing the concentration of IAA, or by the addition of calcium. The inhibitory effect appears to be linked with changes in the properties of the cell walls. Experiments are described which show that lead becomes bound strongly to certain chemical substances involved in cell wall architecture.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00385010
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  • 30
    Digitale Medien
    Digitale Medien
    Effect of growth regulators and role of roots in sex expression in spinach (1978)
    Springer
    Planta 142 (1978), S. 207-210 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Abscisic acid ; Auxin ; Cytokinin ; Flowers (sex) ; Gibberellin ; Sex expression ; Spinacia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract When 7-d-old plantlets of spinach (Spinacia oleracea L.) were immersed with their roots for 24 h in 25 mg/l gibberellic acid (GA3), or 15 mg/l 6-benzylaminopurine (6-BAP), or 15 mg/l indole-3-acetic acid (IAA), or 10 mg/l abscisic acid (ABA) and subsequently grown on long (18-h) days, the ratio of plants with male and female flowers, which in the controls was almost 1:1 (48 and 52%, respectively), was greatly altered. The treatments with 6-BAP, IAA and ABA raised the percentage of female plants to 88, 76 and 71%, respectively; the GA3 treatment increased the percent of male plants to 79%. When young, vegetative spinach plants (3 visible leaves) grown in 18-h days were cut a the root neck, and the shoots grown with their bases in nutrient solution, with adventitious roots either being allowed to develop or being systematically removed, 85% of the plants without roots became males, 85% of those with roots became females. But if the cut shoots were first, for 28 h, placed in a 15-mg/l 6-BAP solution and then grown in the absence of roots, the percent of female plants was restored to 84. These results fully agree with those obtained previously with hemp, namely, that plant growth regulators exert a regulating effect on the sex expression of dioecious plants when applied through the roots in early stages of development; that the root system plays an important role in determining the sex of these plants, that this role of the roots is associated with the synthesis of cytokinins in them. Dioecious short- and long-day plants do not differ in these respects.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00388214
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  • 31
    Digitale Medien
    Digitale Medien
    Naturally occuring modifiers of auxin-receptor interaction in corn: Identification as benzoxazolinones (1978)
    Springer
    Planta 142 (1978), S. 103-107 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Benzoxazolinones ; Receptors ; Supernatant factor ; Zea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A naturally-occurring material termed ‘supernatant factor’ [Ray, P.R., Dohrmann, U., Hertel, R.: Plant Physiol. 59. 357–364 (1977)], which has the property of modifying the binding affinity of auxins to receptor sites, has been isolated from corn (Zea mays L.) and characterised as a mixture of 6-methoxy-2-benzoxazolinone (MBOA) and 6,7-dimethoxy-2-benzoxazolinone (DMBOA). DMBOA is about 50 times more active than MBOA in inhibiting binding of the auxin 1-naphthylacetic acid to membrane-bound or solubilised receptors. The activity of these compounds and the parent analogue in inhibiting auxin binding is correlated with their ability to inhibit auxin-induced growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00385127
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  • 32
    Digitale Medien
    Digitale Medien
    Fluxes and compartmentation of K+, Na+ and Cl−, and action of auxins in suspension-cultured Petroselinum cells (1978)
    Springer
    Planta 143 (1978), S. 213-223 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Compartmental analysis ; Ion fluxes ; Petroselinum ; Suspension culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Transport of 86Rb+/K+, 22Na+, 36Cl−, and [3H]indole acetic acid (IAA) has been studied on suspension-cultured cells of the parsley, Petroselinum crispum (Mill) Nym. By compartmental analysis two intracellular compartments of K+, Na+, and Cl− have been identified and ascribed to the cytoplasm and vacuole; half-times of exchange were around 200 s and 5 h, respectively. According to the Ussing-Teorell flux equation, active transport is required for the influx into the cytoplasm at the plasmalemma (K+, Cl−) and the tonoplast (K+, Na+, Cl−). The plasmalemma permeability pattern, PK:PNa:PCl=1.00:0.24:0.38, features an increased chloride permeability compared with cells from higher plant tissues. IAA uptake showed an exponential timecourse, was half-maximal after 10 min, and a linear function of the IAA concentration from 10−9 to 10−5 M. IAA and 2,4-dichlorophenoxy acetic acid reduce the apparent influx of K+, Na+, Cl− during the initial 30 min after addition and subsequently accelerate both in- and efflux of these ions. We discuss that auxins could affect the ion fluxes in a complex way, e.g. by protonophorous activity and by control of the hypothetical proton pump.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00387792
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  • 33
    Digitale Medien
    Digitale Medien
    Ribosome metabolism in hormone-treated Jerusalem artichoke tuber slices in the absence and presence of 5-fluorouracil (1977)
    Springer
    Planta 135 (1977), S. 267-273 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Cytokinin ; 5-Fluorouracil ; Helianthus ; Ribosome synthesis and activity ; Tuber
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In order to examine the relation of protein synthesis to the onset of growth, changes in ribosome content and activity were compared in aged, metabolically active Jerusalem artichoke (Helianthus tuberosus L.) slices incubated in water or 2,4-dichlorophenoxyacetic acid+kinetin. In water, cells do not grow or divide and rRNA and protein levels remain constant. The percentage membrane-bound (mb) ribosomes drops from 25% to 16% during 24h. At the same time the proportion of ribosomes active in protein synthesis in both free and mb populations declines from about 69% to 54%. In auxin+kinetin, cell expansion occurs and is accompanied by a 3-fold increase in rRNA and a 50% increase in total protein content. The percentage mb ribosomes remains at 25% throughout 48 h of growth. During the first 24h of growth 70% of ribosomes in both free and mb populations are active; this value declines to near water levels at 48 h. Considering the large increase in total ribosomes the number of synthetically active ribosomes is substantially increased during growth. 5-Fluorouracil (5-FU) does not inhibit hormone induced growth but does depress total rRNA content by about one-third. It also reduces [3H]uridine incorporation into ribosomes by 70% and the newly made ribosomes are mostly inactive in protein synthesis. On the other hand, the inhibitor does not significantly affect the proportion of total ribosomes active in protein synthesis and only partially reduces protein accumulation during the second 24 h of growth. It is suggested that while ribosome production is reduced in 5-FU, ribosome turnover is also retarded resulting in retention of near normal capacity for protein synthesis and growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384899
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  • 34
    Digitale Medien
    Digitale Medien
    Meristem differentiation in Riella helicophylla (Bory et Mont.) Mont. under the influence of auxin or antiauxin (1977)
    Springer
    Planta 135 (1977), S. 289-295 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Antiauxin ; Auxin ; Meristem differentiation ; Riella
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract During the development of the unistratose gemmae of Riella helicophylla, the single intercalary meristem of the very young gemmae is subdivided into two lateral meristems. The duration of the cell reproduction cycle increases from the margin to the median part of the gemmae. This polarization within the meristem disappears after addition of the antiauxin PCIB to the culture medium. PCIB leads to a retardation or blockage of the cell cycle during the light period of the culture. Under the influence of PCIB the amount of starch in the chloroplasts is strikingly increased, probably because of a reduction of starch degradation. Addition of sugars compensates the effect of PCIB on the cell cycle. The effects of PCIB are counteracted by auxin. The results are taken as evidence that auxin plays a role in directing the transport of substances needed for the continuation of the cell reproduction cycle between adjacent cells of the meristem.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384902
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  • 35
    Digitale Medien
    Digitale Medien
    Some quantitative effects of indoleacetic acid on the wood production and tracheid dimensions of Picea (1977)
    Springer
    Planta 134 (1977), S. 223-228 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Cambium ; Gibberellin ; Picea ; Tracheids-wood production
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The diameter and wall thickness of tracheids produced after indoleacetic acid treatment were not significantly different from those of the intact controls, for the first few weeks after treatment of disbudded shoots of Picea abies Karst. and Picea sitchensis (Bong.) Carr. However, lateral application of indoleacetic acid (IAA) to intact shoots increased both tracheid diameter and wall thickness; it is suggested that IAA acted synergistically with another endogenous growth regulator, which was also removed by disbudding. Increase in wall thickness after exogenous IAA was associated with increase in duration of the wall thickening phase of tracheid differentiation; this is discussed in relation to the seasonal change from early to latewood. Cambial dormancy was induced by disbudding during active wood production. Since this occurred with or without the presence of current leaves, it is concluded that in Picea continued cambial activity depends upon supply of auxin from the buds, and cannot be supplied from expanded leaves or from the internode itself. Neither indoleacetic acid nor gibberellic acid stimulated renewed cambial activity when applied after the cessation of wood production. With both disbudded and intact shoots, the effectiveness of exogenous IAA declined with time, probably due to decreasing penetration through callus developing at the wounded surface. It is suggested that this apparent change in IAA effectiveness may explain some discrepancies between the results of previous observers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384186
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  • 36
    Digitale Medien
    Digitale Medien
    Abscisic acid and apical dominance in Phaseolus coccineus L. (1977)
    Springer
    Planta 134 (1977), S. 295-299 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Abscisic acid ; Apical dominance ; Auxin ; Gibberellin ; Hormone transport ; Phaseolus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Abscisic acid (ABA) in lanolin, applied to the internode of decapitated runner bean plants enhances the outgrowth of lateral buds. The optimum concentration of the paste is 10-5 M. The effect of ABA is counteracted by indoleacetic acid (IAA) but not by gibberellic acid (GA3). There is no effect when ABA is applied to the apical bud or lateral buds of intact plants. However, 13.2 ng given to the lateral buds of decapitated plants stimulate their growth, whereas higher concentrations are inhibitory. Consequently, ABA enhances growth of lateral buds directly, but only when apical dominance is already weakened. The growth of the decapitated 2nd internode was not affected by ABA. Radioactivity from [2-14C] ABA, applied to nonelongating 2nd internode stumps of decapitated runner bean plants moves to the lateral buds, whereas [1-14C]IAA-and [3H]GA1-translocation is much weaker. ABA transport is inhibited if IAA or [3H]GA1 is applied simultaneously. In elongating internodes [14C]ABA is almost completely immobile. [14C]IAA-and [3H]GA1-translocation is not affected by ABA. The amount of radioactivity from labelled ABA, translocated to the lateral buds, is highest during the early stages of bud outgrowth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384196
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  • 37
    Digitale Medien
    Digitale Medien
    Rapid differentiation of tracheary elements in cultured explants of Jerusalem artichoke (1977)
    Springer
    Planta 135 (1977), S. 207-212 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Cytokinin ; Explants ; Helianthus ; Tuber (explants) ; Xylem differentiation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract the culture of Jerusalem artichoke (Helianthus tuberosus L.) tuber explants on filter paper discs moistened with liquid medium resulted in rapid and consistent xylem differentiation. The number of tracheary elements increased in discrete steps, the first at 48 h with a second at 56–58 h, following partially synchronous mitoses at 20 and 30 h. Factors favouring xylem cell differentiation were optimum levels of both an auxin and a cytokinin, low medium nitrogen concentrations, small volumes of medium, and high culture temperatures. A cell counting method employing Feulgen-stained nuclei and suitable for quantifyings small numbers of immature tracheary elements is described.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384891
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  • 38
    Digitale Medien
    Digitale Medien
    Mycoparasitic relationships (1977)
    Springer
    Archives of microbiology 111 (1977), S. 207-224 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Host-parasite relationships ; Ultrastructure ; Papillae ; Infection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The mode of attack and the infection structures of the necrotrophic mycoparasite, Pythium acanthicum, as well as the responses of various fungal hosts to parasitism were studied using both electron and light microscopy. Many taxonomically distinct fungal hosts were used, though Phycomyces blakesleeanus, Pythium aphanidermatum, Rhizoctonia solani and a basidiomycete identified as Corticium sensu lato were studied in greatest detail. Parasitism was by direct penetration of the fungal host without appressorium formation by the parasite. The host's cells responded to contact by P. acanthicum by forming papillae. The morphological features of the papillae varied with the particular host. In P. blakesleeanus they were comprised of vesicles and segments of cytoplasm entrapped in a fibrillo-granular matrix, while in R. solani and the Corticium basidiomycete they contained considerable amounts of electron-opaque and electron-translucent material. Evidence for both mechanical and enzymatic penetration of the host fungi by the parasite are presented. Details of host wall and septum penetration by the parasite are presented using time-lapse light microscopy with in vivo systems. Many of these stages of parasitism were examined ultrastructurally. Some comparisons of these mycoparasitic relationships are discussed in relation to what is known from the literature about phytoparasitic interactions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00549358
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  • 39
    Digitale Medien
    Digitale Medien
    Gametangial development in Allomyces macrogynus (1977)
    Springer
    Archives of microbiology 113 (1977), S. 163-172 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Allomyces ; Phycomycete ; Ultrastructure ; Gametangial differentiation ; Autophagy ; Gamma bodies ; Multivesicular bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The ultrastructure of gametangial development in Allomyces macrogynus was determined from longitudinal sections of gametophytic hyphae at stages of differentiation from vegetative apices at time zero to fully cleaved gametangia at about 150 min. Whereas vegetative hyphae show an apical clustering of mitochondria, cytoplasmic vesicles and microtubules, this arrangement was sharply altered in early development. Mitochondria were evenly redistributed, apical vesicles and microtubules disappeared, and autophagic vacuoles became prominent. Subsequently, electron-dense granules and microbody/lipid droplet complexes became evident and later, during gamete cleavage, developed into gamma bodies and side-body complexes respectively. Meanwhile cytoplasmic vesicles were involved in exit papilla formation. The significance of autophagic vacuoles and multivesicular bodies is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00492020
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  • 40
    Digitale Medien
    Digitale Medien
    Dorsal-ventral differentiation in Simonsiella and other aspects of its morphology and ultrastructure (1977)
    Springer
    Archives of microbiology 113 (1977), S. 197-204 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Gliding bacterium ; Simonsiella ; Oral cavity ; Electron microscopy ; Morphology ; Dorsal-ventral differentiation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The morphology and ultrastructure of the aerobic, Gram-negative multicellular-filamentous bacteria of the genus Simonsiella were investigated by scanning and transmission electron microscopy. The flat, ribbon-shaped, multicellular filaments show dorsal-ventral differentiation with respect to their orientations to solid substrata. The dorsal surface, orientated away from the substrate, is convex and possesses an unstructured capsule. The ventral surface, on which the organisms adhere and glide, is concave and has an extracellular layer with fibrils extending at right angles from the cell wall. The cytoplasm in the ventral region contains a proliferation of intracytoplasmic membranes and few ribosomes in comparison to the cytoplasm in other parts of the cell. Centripetal cell wall formation is asymmetrical and commences preferentially in the ventral region. Quantitative differences in morphology and cytology exist among selected Simonsiella strains. Functional aspects of this dorsalventral differentiation are discussed with respect to the colonization and adherence of Simonsiella to mucosal squamous epithelial cells in its ecological habitat, the oral cavities of warm-blooded vertebrates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00492025
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  • 41
    Digitale Medien
    Digitale Medien
    Two unicellular cyanobacteria which reproduce by budding (1977)
    Springer
    Archives of microbiology 115 (1977), S. 249-257 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Chamaesiphon spp. ; Cyanobacteria ; Reproduction by budding ; Ultrastructure ; Nutritional properties ; DNA base composition ; Fatty acid composition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two strains of unicellular cyanobacteria which reproduce exclusively by budding are described and assigned to genus Chamaesiphon.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00446449
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  • 42
    Digitale Medien
    Digitale Medien
    Micromorphology of Gram-negative hydrogen bacteria (1977)
    Springer
    Archives of microbiology 114 (1977), S. 93-100 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Ultrastructure ; Micromorphology ; Gram-negative hydrogen bacteria ; Flagellation ; Flagellar fine structure ; Pili
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The cell morphology, the arrangement and fine structure of flagella and the piliation of the following Gram-negative aerobic hydrogen bacteria have been studied: Alcaligenes eutrophus, Alcaligenes paradoxus, Alcaligenes ruhlandii, Pseudomonas flava, Pseudomonas pseudoflava, Pseudomonas palleronii, Pseudomonas facilis, Aquaspirillum autotrophicum, Paracoccus denitrificans, Corynebacterium autotrophicum, and strains MA 2 and SA 35. The identity of the bacteria was examined by their substrate spectra and type of flagellation. Three types of flagellar fine structure were differentiated. The presence of pili was noted in strains of Alcaligenes paradoxus, Pseudomonas flava, P. pseudoflava, P. palleronii, and P. facilis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00410769
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  • 43
    Digitale Medien
    Digitale Medien
    The effect of aminopterin (4-amino folic acid) on growth and cell division of fermentative versus oxidative yeasts (1977)
    Springer
    Archives of microbiology 113 (1977), S. 293-302 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Aminopterin ; Saccharomyces cerevisiae ; Polyploid ; Oxidative-fermentative yeast ; Ultrastructure ; Bioassay ; Synchrony
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In a related brewing study detailed characteristics of fermentations displaying effective yeastaminopterin interaction were presented. Fermentative yeast types (certain Saccharomyces species and Selenotila intestinalis) proved effective aminopterin reactors whereas oxidative yeasts (certain Candida, Cryptococcus, Pichia, Rhodotorula, Saccharomyces, and Trigonopsis species) proved ineffective reactors. In general effective reactors were polyploids characterized by the lack of film or pellicle formation and ineffective reactors the opposite. In stationary fermentations the Fleischmann 139 strain of S. cerevisiae proved a fair reactor. When aerated it proved an ineffective reactor and aminopterin or products there-of stimulated growth. Conversely aeration enhanced aminopterin activity of effective reactor yeasts. The positive effect of biotin on aminopterin activity and the negative effect of yeast extract, L-asparagine, adenine and thymine is shown and compared and contrasted with earlier reported studies. These findings supported by outside data suggest that oxidative yeasts (and bacteria) can readily elicit enzymes capable of inactivating aminopterin whereas fermentative types are lacking in this capability. Finally that past yeast-aminopterin studies were conducted with oxidative yeast types. Advantages of effective aminopterin reactor yeasts to be published elsewhere include improved ultrastructure using KMnO4−OsO4 fixation, a yeast bioassay procedure for detecting aminopterin in plasma and urine, and cell synchronization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00492038
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  • 44
    Digitale Medien
    Digitale Medien
    Micromorphology of Gram-negative hydrogen bacteria (1977)
    Springer
    Archives of microbiology 114 (1977), S. 101-110 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Ultrastructure ; Micromorphology ; Gram-negative ; Hydrogen bacteria ; Cell envelope ; Cytoplasmic inclusions ; Membranes ; Mesosomes ; Glycogen ; Poly-β-hydroxybutyrate ; Cell wall types
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The fine structure of the cell envelope, of membrane systems and of cytoplasmic inclusions of Gram-negative aerobic hydrogen bacteria has been studied. The results have been tabulated, and three main groups could be recognized: Group 1: Alcaligenes eutrophus, A. paradoxus, A. ruhlandii, Pseudomonas facilis, P. flava, P. pseudoflava, P. palleronii, and Aquaspirillum autotrophicum; Group 2: “Corynebacterium” autotrophicum and strains MA 2 and SA 35; Group 3: Paracoccus denitrificans. Special structures related to the chemoautotrophic way of life of the hydrogen bacteria were not observed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00410770
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  • 45
    Digitale Medien
    Digitale Medien
    Disappearence of the intracytoplasmic membranes inRhodopseudomonas sphaeroides (1978)
    Springer
    Archives of microbiology 117 (1978), S. 293-295 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Rhodopseudomonas sphaeroides ; Intracytoplasmic membranes ; Membranes ; Ultrastructure ; Bacteriochlorophyll ; Chromatophores
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The photosynthetic bacterium,Rhodopseudomonas sphaeroides, can be grown phototrophically (light, anaerobiosis), of chemotrophically (dark, aerobiosis). In the first case, it contains intracytoplasmic membranes with photosynthetic pigments. When shifted from phototrophy to chemotrophy these membranes disappear in an unknown fashion. In the present experiment, samples were taken for electron microscopy, cell density and bacteriochlorophyll determinations after shift from phototrophy to chemotrophy. The density of intracytoplasmic vesicles was measured on micrographs. During the first 2h growth is very slow and the ultrastructure remains unaltered. As growth resumes, the vesicles disappear at a rate which implies that they are not incorportated into the cytoplasmic membrane, nor actively digested, but remain intact and become increasingly diluted in the cytoplasm as the culture grows. The size of the vesicles was estimated to about 500 Å. The number of vesicles in phototrophically grown cells was calculated to about 575 per cell, and after 6h chemotrophic growth to about 100. The areas of the cytoplasmic and intracytoplasmic membranes are roughly calculated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00738549
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  • 46
    Digitale Medien
    Digitale Medien
    Sporogenesis in Streptomyces melanochromogenes (1978)
    Springer
    Archives of microbiology 118 (1978), S. 309-316 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Streptomyces melanochromogenes ; Sporogenesis ; Formation of sporulation septum ; Delimitation, separation, and release of spores ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The mode of spore differentiation in a strain of Streptomyces melanochromogenes was followed by analysis of ultrathin sections of sporulating aerial hyphae at various stages of sporogenesis. A special accent was laid on the formation of the sporulation septum and its alterations in the course of spore delimitation and separation. Distinct differences in formation and substructure have been observed between the cross walls of vegetative hyphae and the sporulation septa. Cross walls of vegetative hyphae are formed in a way typical for Gram-positive bacteria by a centripetal annular ingrowth of cytoplasmic membrane, on which wall material immediately is deposited. The development of the sporulation septa is characterized by the accumulation of amorphous material in addition to the newly synthesized wall layer inside the invaginating cytoplasmic membrane. This amorphous septal material will later be decomposed presumably by two lytic systems which cause the separation of the spores. The central region of the finished sporulation septum is perforated by microplasmodesmata. Spores are released by a break down of the surface sheath. The complete spores are enveloped by a twolayered cell wall and the spiny surface sheath.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00429123
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  • 47
    Digitale Medien
    Digitale Medien
    Synaptonemal complexes in antheridia of Achlya ambisexualis E87 (1977)
    Springer
    Archives of microbiology 112 (1977), S. 311-313 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Achlya ; Synaptonemal complexes ; Oömycetes ; Ultrastructure ; Gametangial meiosis ; Mycology ; Antheridium
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This is the first report of longitudinal sections of synaptonemal complexes in oömycetous fungi. These indicators of meiosis were observed in antheridial nuclei of Achlya ambisexualis E87. They were attached to a platelike structure at the inner membrane of the nuclear envelope. The lateral elements were separated from each other by an average distance of 160 nm. These results provide new ultrastructural evidence for gametangial meiosis in Oömycetes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00413099
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  • 48
    Digitale Medien
    Digitale Medien
    Ultrastructural study of microcyclic macroconidiation in Neurospora crassa (1978)
    Springer
    Archives of microbiology 116 (1978), S. 279-288 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Neurospora crassa ; Macroconidia ; Microcycle ; Heat ; Ultrastructure ; Nucleolus ; Proconidia ; Septa
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Heat-shock of macroconidia of Neurospora crassa at 46°C followed by shift-down to 25°C determines premature conidiogenesis. The nuclei and cytoplasm of heat-treated, swollen conidia contain spots of a dense material especially concentrated around the nucleolus in short time treated ones. In the first proconidium apically budding on the enlarged tip of the premature conidiophore, small vesicles are peripherally spread. A few such vesicles are later seen lining the initially simple septum separating the proconidial units into conidia. The doubling of this interconidial septum is surface viewn as a thick annulus. Disarticulation of the conidial units intervenes along a septal furrow of electroluscent material. Interconidial continuity through the septal pores is transiently insured by a connective which is ruptured for final liberation of the conidia.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00417852
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  • 49
    Digitale Medien
    Digitale Medien
    Polyhedral inclusion bodies in cells of nitrosomonas spec (1977)
    Springer
    Archives of microbiology 112 (1977), S. 69-72 
    Details
    ISSN: 1432-072X
    Schlagwort(e): Nitrosomonas spec ; Ammonia oxidizing bacterium ; Polyhedral inclusion bodies ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Polyhedral inclusion bodies were observed in cells of a Nitrosomonas species. They were present in growing cells as well as in resting cells. In thin sections their size was about 130 nm in growing cells and about 185 nm in diameter in resting cells. The bodies were commonly located in the nucleoplasm. They appeared to be bounded by a nonunit membrane and had a granular substructure. In thin sections about 70% of the exponentially grown cells and about 20% of the resting cells of the investigated strain showed 1–7 respectively 1–3 inclusion bodies.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00446656
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  • 50
    Digitale Medien
    Digitale Medien
    Rapid auxin- and fusicoccin-enhanced Rb+ uptake and malate synthesis in Avena coleoptile sections (1978)
    Springer
    Planta 139 (1978), S. 35-41 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Avena ; Cell elongation ; Ion uptake ; Malate synthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The short-term effects of auxin (indole-3-acetic acid) and fusicoccin (FC) on Rb+ uptake and malate accumulation in Avena sativa L. coleoptile sections have been investigated. FC stimulates 86Rb+ uptake within 1 min while auxin-enhanced uptake begins after a 15–20-min lag period. Auxin has little or no effect on 86Rb+ uptake at external pHs of 6.0 or less, but substantial auxin effects can be observed in the range of pH 6.5 to 7.5. Competition studies indicate that the uptake mechanism is specific for Rb+ and K+. After 3 h of auxin treatment the total amount of malate in the coleoptile sections is doubled compared to control sections. FC causes a doubling of malate levels within 60 min of treatment. Auxin-induced malate accumulation exhibits a sensitivity to inhibitors and pH which is similar to that observed for the H+-extrusion and Rb+-uptake responses. Both auxin- and FC-enhanced malate accumulation are stimulated by monovalent cations but this effect is not specific for K+.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00390807
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  • 51
    Digitale Medien
    Digitale Medien
    Identification and measurement of indoleacetic and abscisic acids in the cambial region of Picea sitchensis (Bong.) Carr. by combined gas chromatography-mass spectrometry (1978)
    Springer
    Planta 139 (1978), S. 133-138 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Abscisic acid ; Auxin ; Cambium ; Picea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Indole-3-acetic acid (IAA) and abscisic acid (ABA) were identified by combined gas chromatography-mass spectrometry (GCMS) in fractions obtained by diffusion and extraction from bark peelings of Sitka spruce. A procedure is described for the quantitative analysis of IAA and ABA levels in the same extract using the GCMS technique of single-ion current monitoring. This procedure was used to measure the diffusible, free, and bound fractions of IAA and ABA in the cambial region of Sitka spruce throughout one year; the range in concentration for these fractions was 0.06–0.30, 0.46–3.85, and 0.04–0.20 μg/g oven-dry weight, respectively, for IAA, and 0–0.08, 0.03–2.21, and 0.13–0.66 μg/g oven-dry weight, respectively, for ABA. Movement in the cambial region was found to be polar for endogenous IAA and nonpolar for endogenous ABA. Recoveries of [14C]IAA internal standards showed that 73–99.5% of the IAA was lost during purification, and that there could be up to 5-fold differences in recovery between purifications, indicating that IAA loss shold be measured in quantitative analyses.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00387138
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  • 52
    Digitale Medien
    Digitale Medien
    Morphological aspects of the galactomannan formation in the endosperm ofTrigonella foenum-graecum L. (Leguminosae) (1977)
    Springer
    Planta 133 (1977), S. 243-248 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Endosperm ; Galactomannan ; Secretion ; Ultrastructure ; Trigonella
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The mode of deposition (secretion) of galactomannan in the cells of the seed endosperm ofTrigonella foenum-graecum has been studied by electron microscopy. In cells which are just beginning to secrete galactomannan there are stacks of rough endoplasmic reticulum (ER). The intracisternal space (containing the enchylema) of the rough ER then swells, becomes vacuolated and forms a voluminous network, with “pockets” of cytoplasm entrapped within poculiform rough ER. The enchylema contains material which reacts with periodate-thiocarbohydrazidesilver proteinate in a very similar manner to the galactomannan already deposited in the cell wall. It appears that the galactomannan is formed in the intracisternal space of the rough endoplasmic reticulum and then expelled outside the plasmalemma. This mode of deposition contrasts with that of other plant cell wall polysaccharides whose secretion is mediated by Golgi vesicles.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00380684
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  • 53
    Digitale Medien
    Digitale Medien
    Rapid-growth responses of corn root segments: Effect of auxin on elongation (1977)
    Springer
    Planta 135 (1977), S. 1-5 
    Details
    ISSN: 1432-2048
    Schlagwort(e): Auxin ; Cell elongation ; Elongation ; Root growth ; Zea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of indole-3-acetic acid (IAA) on the elongation rates of 2 mm corn (Zea mays L.) root segments induced by citrate-phosphate buffer (or unbuffered) solutions of pH 4.0 and 7.0 was studied. At pH 7.0, auxin initially reduced the elongation rate in both buffered and unbuffered solutions. Only in buffer at pH 7.0 was auxin at a concentration of 0.1 μM found to promote the elongation rate though briefly. THis promoted rate represented only ca. 20% of the rate achieved with only buffer at pH 4.0. Auxin in pH 4.0 buffered and unbuffered solutions only served to reduce the elongation rates of root segments. Some comparative experiments were done using 2 mm corn coleoptile segments. Auxin (pH 6.8) promoted the elongation rate of coleoptile segments to a level equal or greater than the maximal H ion-induced rate. The two responses of root segments to auxin are compared to auxin action in coleoptile growth.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00387967
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  • 54
    Digitale Medien
    Digitale Medien
    The ultrastructure of the sinus gland of Gammarus oceanicus (Crustacea: Amphipoda) (1977)
    Springer
    Cell & tissue research 182 (1977), S. 557-564 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Sinus gland ; Gammarus ; Neurosecretion ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The sinus gland of Gammarus oceanicus, like that of other crustaceans, is composed of three elements: neurosecretory axons, glial cells and stromal sheath. Five neurosecretory axon types are identified on the basis of granule diameter, shape, and electron density, and axon matrix density. Exocytosis appears to be the major release mechanism of neurosecretory material. The preterminal regions of neurosecretory axons contain axoplasmic reticulum and neurotubules. Their arrangement in the axon and relationship with one another suggest a transport function. Multilamellar bodies are found in the terminal regions of neurosecretory axons. They arise from mitochondria and may be involved in granulolysis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219838
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  • 55
    Digitale Medien
    Digitale Medien
    An ultrastructural analysis of the gametes and early fertilization in two bivalve molluscs, Chama macerophylla and Spisula solidissima with special reference to gamete binding (1977)
    Springer
    Cell & tissue research 182 (1977), S. 469-489 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Fertilization ; Molluscs ; Spermatozoon ; Oocyte ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An ultrastructural investigation of the gametes and their interaction during the early events of fertilization in molluscs has been performed. A gamete binding event involving large numbers of sperm has been identified and examined in detail. The surface of the oocyte is projected into numerous microvilli which extend through the vitelline envelope. Tufts of fibrillar material radiate from the tips of these microvilli, forming a layer external to the vitelline envelope. The acrosomal vesicle of the mature spermatozoon contains two major components, which function differently during fertilization. The vesicle is indented at its adnuclear surface, constituting a preformed acrosomal tubule. This tubule does not elongate during the acrosome reaction. Completion of the reaction results in the formation of an extracellular coat, derived from one component of the acrosomal vesicle, on the anterior surface of the sperm. Sperm-egg binding is accomplished by an association of the extracellular coat on the reacted sperm and the fibrous tufts on the tips of the microvilli of the oocyte. Evidence that gamete membrane fusion occurs by fusion of the acrosomal tubule and a microvillus is presented. These observations provide a generalized pattern of molluscan fertilization.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219830
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  • 56
    Digitale Medien
    Digitale Medien
    The role of the haemocytes of Clitumnus extradentatus in haemolymph coagulation (1977)
    Springer
    Cell & tissue research 182 (1977), S. 513-524 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Haemocytes ; Insects ; Haemolymph coagulation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Light and electron-microscopic observations of the blood cells (haemocytes) of the stick insect Clitumnus extradentatus in vitro showed that two morphologically distinct cell types, the cystocytes and granular cells are involved in haemolymph coagulation. Both these cell types contain a variable number of electron-dense granules which upon release cause progressive coagulation and precipitation of the haemolymph. In the cystocytes this release is extremely rapid (30–60s) while in the granular cells it only occurs after 1–2min in vitro. The role of these cells in haemostasis is discussed together with the possible significance of the involvement of two cell types in the coagulation process.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219833
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  • 57
    Digitale Medien
    Digitale Medien
    Ultrastructural tracer studies on the permeability of the Malpighian tubule of the Pill Millipede, Glomeris marginata (Villers) (1977)
    Springer
    Cell & tissue research 182 (1977), S. 549-556 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Malpighian tubules ; Millipede ; Ultrastructure ; Tracers ; Formed bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The electron-dense tracers ferritin, and iron-dextran, and the protein horseradish peroxidase, have been used to investigate the ultrastructural basis of permeability in the upper and lower segments of the Malpighian tubules of Glomeris marginata. All these materials were able to cross the basal lamina and enter the tubule lumen of the upper segment, and it was established that horseradish peroxidase was able to enter the channels which interrupt the apical junctions. In the upper segment, ferritin, iron-dextran, and horseradish peroxidase are all taken up and accumulated within intracellular vesicles. In the lower segment ferritin and iron-dextran enter the cells but become generally distributed over the cyptoplasm, as well as entering membrane-bounded vacuoles. The behaviour of horseradish peroxidase could not be assessed owing to the presence of endogenous peroxidase activity in the cells. After fixation by direct application of glutaraldehyde to the undissected tubules, the extracellular spaces contained large numbers of membrane-bounded vesicles. The significance of these observations is discussed in relation to the physiological activities of the tubules.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219837
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  • 58
    Digitale Medien
    Digitale Medien
    Neurosecretion in the basommatophoran snail Bulinus truncatus (Gastropoda, Pulmonata) (1977)
    Springer
    Cell & tissue research 176 (1977), S. 57-67 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Neurosecretion ; Alcian blue ; Alcian yellow staining ; Ultrastructure ; Bulinus truncatus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The neurosecretory system of the freshwater snail Bulinus truncatus was investigated. With the Alcian blue-Alcian yellow (AB/AY) staining method at least 10 different types of neurosecretory cells (NSC) were distinguished in the ganglia of the central nervous system. The differences in staining properties of the NSC — with AB/AY the cells take on different shades of green and yellow — are borne out at the ultrastructural level: the NSC types contain different types of neurosecretory elementary granules. The neurosecretory system of B. truncatus is compared to that of Lymnaea stagnalis, the species which has received the most attention among the pulmonates. It appears from the comparison that the systems of both species show many similarities, although some differences are also apparent.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220344
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  • 59
    Digitale Medien
    Digitale Medien
    Cytological evidence for different types of cerebrospinal fluid-contacting subependymal cells in the preoptic and infundibular recesses of the frog (1977)
    Springer
    Cell & tissue research 176 (1977), S. 317-334 
    Details
    ISSN: 1432-0878
    Schlagwort(e): CSF-contacting subependymal cells ; Frog hypothalamus ; Fluorescence microscopy ; Autoradiography ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Blue-green fluorescent subependymal cells with intraventricular processes were shown by the fluorescent histochemical method to be distributed from the preoptic recess to the infundibular recess of the frog hypothalamus. Electron microscopy revealed at least two types of CSF-contacting subependymal cells, type 1 containing large dense granules (about 100–200 nm in diameter) and type 2 containing small dense core vesicles (about 60–100 nm in diameter). Subsequent to fixation in permanganate solution, the small dense core vesicles in type 2 cells reacted with the fixative and consistently showed a dense content. However, the large granules in type 1 cells were mostly pale or less dense after this fixation. Two hours after intraventricular injection of 3H-dopamine, a large number of silver grains appeared only in the cytoplasm of intraventricular processes possessing dense core vesicles (type 2 cells). A few grains were also found in the perikarya. It is concluded that type 2 cells are catecholamine-storing cells. It is suggested that type 1 cells in the infundibular recess are peptidergic neurons which may secrete some hypothalamic regulating hormones of the anterior pituitary. Most of these cells in the preoptic recess belong to the neurosecretory cells of the preoptic nucleus, while some cells probably function similarly to those in the infundibular recess.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221791
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  • 60
    Digitale Medien
    Digitale Medien
    Ultrastructure of nerve plexus in flatworms (1977)
    Springer
    Cell & tissue research 176 (1977), S. 335-347 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Flatworm ; Nerve-net ; Epithelium ; Ultrastructure ; Synapse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In addition to a submuscular and subepithelial nerve plexus an infra-epithelial nerve-net also occurs in Notoplana acticola. It contains naked nerve cells which lie between the bases of epithelial cells. Individual neurites occur separately or in small tracts. Synapses contain clear spherical vesicles and are polarized. Post-synaptic neurites tend to be flat and ribbon-like. Rhabdite and mucus secreting cells in the epithelium have synapses associated with them. Neurites ending on the rhabdites appear to originate in the subepithelial plexus. The “sensory-free nerve endings” of earlier workers are reinterpreted as being motor terminals on epithelial secretory cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221792
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  • 61
    Digitale Medien
    Digitale Medien
    Ultrastructure of the rat pineal gland grafted under the kidney capsule (1977)
    Springer
    Cell & tissue research 176 (1977), S. 131-142 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pineal gland ; Graft ; Ultrastructure ; Innervation ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Pineal glands were grafted under the kidney capsule of mature male rats for periods of 20, 40, 60 and 100 days. Each grafted gland was then excised and divided into two halves. One half was processed for conventional electron microscopy and the other was fixed in aldehydes and then incubated in a zinc iodide-osmium tetroxide mixture at pH 4.4 (A-ZIO-4.4). During the forty days following the operation pinealocytes showed the typical ultrastructural features associated with cells with a high protein and/or peptide secretory activity. On the other hand, during this period, the number of granular vesicles decreased progressively. From day 40 on, the grafted pinealocytes lacked granular vesicles. During the second half of the experimental period the ultrastructure of the pinealocytes indicated that their secretory activity was considerably decreased. During the acute phase of the experimental period numerous structures regarded as the tip of growing axons as well as typical nerve fibres appeared around blood vessels and within the parenchyma of the grafted gland. In the transplanted tissue obtained 60 and 100 days after the operation the growth cones were scarce, whereas typical nerve endings became numerous. These endings contained small clear vesicles which reacted positively when the tissue was treated with A-ZIO-4.4. The secretory activity of the grafted pineal gland and the nature of the nerve fibres which innervate the graft are discussed. The authors wish to thank Mrs. E.M. Rodríguez de Calderón for her valuable help
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220349
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  • 62
    Digitale Medien
    Digitale Medien
    The fine structure of the compound eye of Squilla mantis (crustacea, stomatopoda) (1977)
    Springer
    Cell & tissue research 176 (1977), S. 205-233 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Eye ; Retina ; Squilla mantis ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fine structure of the compound eye of adult specimens of Squilla mantis was investigated. The eye consists of about 3600–3700 ommatidia, each containing a dioptric apparatus formed by a lamellated corneal lens and a eucone-type crystalline cone. Each of the four cone cells give rise to a cylindrical process (crystalline thread) inserted between the retinula cells and extending down to the basement membrane. Two distal pigment cells completely encompass the distal part of the crystalline cone, becoming progressively smaller and forming roundish processes. At the level of the tip of the crystalline cone they split off into small pigment-containing processes, and a central process leads down to the basement membrane. About 12–16 proximal pigment cells surround the ommatidium and extend from the tip of the crystalline cone to the basement membrane. In addition to the two types of pigment cell, three other types of pigment-containing cells were identified, one of which possibly contains — on the basis of their ultrastructure — crystals of the respiratory pigment hemocyanin. The two other pigments are found respectively on the surface of the retina (green pigment) and beneath the surface and in the intraommatidial space (white pigment). The distal part of each ommatidium consists of retinula cells of about equal size. Further proximal an 8th small retinula cell is encountered. The fused, centrally located rhabdom, is built up of the microvilli (rhabdomeres) of the 7 large retinula cells, the 8th has no microvilli. The structure of the ommatidia was also examined in relation to light-dark adapted conditions (LA-DA). In DA the crystalline cone shortens and the rhabdom becomes longer by an approximately corresponding amount and the pigments of the distal pigment cells expand more distally. The number and type of special cytoplasmic inclusions, as well as the shape and size of the socalled perirhabdomal vacuoles, seems not to be changed by light or dark-adaptation. In the 7 large retinula cells, an unusual migration of pigment granules occurs under DA conditions (the 8th does not contain pigment granules). In DA, many of granules which are distributed around the rhabdom in LA, line up in rows, like strings of pearls, along the rhabdom, forming a dense pigment coat around it. The findings are compared with those of related studies and their functional implications for the vision of Squilla are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00229463
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  • 63
    Digitale Medien
    Digitale Medien
    Fine structure of the corpus luteum of pregnancy in the gerbil (Meriones unguiculatus) (1977)
    Springer
    Cell & tissue research 176 (1977), S. 361-371 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Corpus luteum ; Gerbil (Meriones) ; Pregnancy ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Corpora lutea from gerbils on days 1, 4, 8, 12, 16, 20 and 24 of pregnancy were studied electron microscopically. Similarly, luteal tissue from animals on the day of parturition and one day postpartum was studied (gestation: 24 days ± 8–24h). Agranular endoplasmic reticulum increases in quantity through day 16 and thereafter is somewhat reduced. Granular endoplasmic reticulum and a population of small granules (type I) become abundant during late pregnancy and their possible role in the production and storage of relaxin is discussed. Luteal tissue undergoes a relatively rapid regression which begins on the day of parturition. Conspicuous in the regressing luteal tissue are large (type II) granules (possibly lysosomes), lipid droplets, leucocytic elements and macrophages. Functional correlates of these morphological findings are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221794
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  • 64
    Digitale Medien
    Digitale Medien
    The villous stroma of the human placenta (1977)
    Springer
    Cell & tissue research 177 (1977), S. 105-121 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Human placenta ; Villous stroma ; Fixed stromal cells ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In human placental villi the connective tissue is constructed by mesenchymal cells, small and large reticulum cells and fibroblasts. During early pregnancy mesenchymal cells dominate; starting with the third month of gestation the reticulum cells are in the majority within the terminal villi, the fibroblasts within the stem villi. Ultrastructurally intermediary types of cells can be differentiated. Together with reticular and collagenous fibres the reticulum cells form the basic architecture of the villous stroma during the first 2/3 of gestation: the “reticular type of stroma”. This consists of a network of cells and fibres with fetal vessels fitted in between. The remaining interspaces form a fluid system of compartments in which Hofbauer cells are suspended. They are called stromal channels. During the last trimester these channels and the Hofbauer cells as well are progressively replaced either by voluminous masses of fibres (“fibrous type of stroma”, mainly in the stem villi) or by sinusoidal enlargements of fetal capillaries (“sinusoidal type of stroma”, mainly in the terminal villi).
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221122
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  • 65
    Digitale Medien
    Digitale Medien
    The accessory outer segment of rods and cones in the retina of the guppy, Poecilia reticulata P. (teleostei) (1977)
    Springer
    Cell & tissue research 177 (1977), S. 181-193 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Accessory outer segment ; Photoreceptors ; Poecilia reticulata P. ; Ultrastructure ; Microtubules
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the accessory outer segment (AOS) — a ciliumlike structure emanating from the inner segment and running alongside the outer segment of photoreceptors — is described. The AOS occurs in both rods and cones of Poecilia reticulata. Its ultrastructure, including the arrangement of microtubules, which originate from the ciliary stalk, is the same in rods and cones. The cone-AOS is connected with the outer segment by a thin plasmabridge, whereas the rod-AOS lies embedded within the outer segment. The outer segment of the cone, in contrast to that of the rod, is separated from the pigment epithelium by a large extracellular space. An intimate contact, however, is secured by the AOS; its membrane is closely appositioned to the pigment epithelium membrane. The functional significance of the AOS and its possible occurrence in other vertebrate classes, are discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221080
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  • 66
    Digitale Medien
    Digitale Medien
    Ultrastructural changes in midgut cells of female Aedes aegypti L. (insecta, diptera) after starvation or sugar diet (1977)
    Springer
    Cell & tissue research 177 (1977), S. 215-219 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Aedes aegypti ; Midgut epithelium ; Ultrastructure ; Starvation ; Sugar diet
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Nach einer Hungerperiode von 5 bzw. 8 Tagen ist die Ultrastruktur der Epithelzellen im hinteren Abschnitt des Mitteldarmes weiblicher A. aegypti teilweise verändert. So wird beispielsweise eine drastische Reduktion des rauhen endoplasmischen Retikulum (rer) gemessen, das für die Synthese der Enzyme zur Blutverdauung verantwortlich ist. Einen ähnlichen Einfluß auf das rer hat eine gleich lang dauernde Fütterung der Mücken mit Zuckerwasser.
    Notizen: Summary The ultrastructure of the epithelial cells in the posterior part of the midgut in female Aedes aegypti was partly changed after starvation periods of 5 or 8 days. Most obvious is a drastic reduction of the amount of rough endoplasmic reticulum (rer), which is responsible for the synthesis of enzymes for blood digestion. A similar influence on rer membranes is to be observed in mosquitoes fed on sucrose solution only, without additional blood meals.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221082
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  • 67
    Digitale Medien
    Digitale Medien
    The effect of age on the ultrastructure of the mid-gut cells of the hymenopteran Nasonia vitripennis (Walk.) (Hymenoptera, Pteromalidae) (1977)
    Springer
    Cell & tissue research 177 (1977), S. 239-245 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Insects ; Mid-gut ; Aging ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the mid-gut cells of aged female Nasonia vitripennis is described. The mid-gut is a shrunken and distorted organ in the aged animal. The individual cells are highly disorganised and the organelle components are altered. The small lipid droplets formed in the apical cell region do not coalesce to form the large central lipid inclusions characteristic of the young animal. The rough endoplasmic reticulum is reduced and some of the mitochondria enlarge. The mid- and apical cell regions also contain large numbers of cytolysosomes. The basal cell region is essentially unchanged, but the channels formed by the infolded basal plasma membranes are dilated. The changes observed are discussed in relation to previous observations on other insect species.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221085
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  • 68
    Digitale Medien
    Digitale Medien
    Ultrastructural evidence for the existence of steroid synthesizing cells in the ovary of the starfish, Asterias rubens (Echinodermata) (1977)
    Springer
    Cell & tissue research 182 (1977), S. 275-279 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Steroid synthesizing cells ; Steroidogenesis ; Ovary ; Ultrastructure ; Echinodermata, Asterias rubens
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of cells showing characteristic features of steroid producing cells in the ovaries of the starfish, Asterias rubens, is described. The correlation between the appearance of these cells and steroid biosynthesis in ovarian tissue of A. rubens is discussed. The importance of the discovery of these cells in view of the biosynthesis of steroids and the phylogeny of Echinodermata is mentioned.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220596
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  • 69
    Digitale Medien
    Digitale Medien
    Morphological alterations and functional changes of interhepatocellular junctions induced by bile duct ligation (1977)
    Springer
    Cell & tissue research 182 (1977), S. 299-310 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Liver ; Bile duct ligation (rat) ; Cell membrane ; Intercellular junctions ; Ultrastructure ; Freeze-fracturing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effect of bile duct ligation on the intercellular junctions of hepatocytes was investigated. The features and the arrangement of the bile canaliculi and the zonulae occludentes alter concomitant to the increase of the intracanalicular pressure. The lumen of the bile canaliculi enlarges and the microvilli disappear. The array of the zonulae occludentes becomes irregularly shaped, the number of strands diminishes and interruptions of the strands occur. With peroxidase a leakage in the bile-blood barrier is detected. Furthermore a disappearance of gap junctions between the hepatocytes after bile duct ligation is observed. The present investigation shows that the zonulae occludentes are mobile structures which are changed by increased unilateral pressure. Due to their ultrastructural alterations, a leakage of the permeability barrier between physiological compartments is found. We acknowledge the helpful criticism and discussion of Prof. H.D. Fahimi. We are indebted to Mrs. B. Brühl, M. Bürkle and Ch. Walenta for technical assistance, and to stud. med. Jon Greenberg for preparing the manuscript
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219766
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  • 70
    Digitale Medien
    Digitale Medien
    Electron microscopic study of the mandibular glands of Kalotermes flavicollis Fabr. (Isoptera; Calotermitidae) (1977)
    Springer
    Cell & tissue research 182 (1977), S. 327-339 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Ultrastructure ; Mandibular glands ; Kalotermes ; Polymorphism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Les glandes mandibulaires de Calotermes sont étudiées dans les différentes castes. Elles présentent un dimorphisme sexuel chez les soldats et les sexués. Après la mue imaginale, les cellules glandulaires ont toujours une activité sécrétrice. De plus, chez les soldats femelles et les reines, elles contiennent de nombreuses formations cristallines d'origine mitochondriale. Le rôle de ces glandes (sécrétion de salive ou de phéromone) est discuté.
    Notizen: Summary The mandibular glands of Kalotermes were examined in different castes. They showed sexual dimorphism in the soldiers and primary reproductives. Moreover, in female soldiers and queens, mandibular gland cells contained numerous crystalline structures of mitochondrial origin. The role of these glands (secretion of saliva or pheromone) is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219768
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  • 71
    Digitale Medien
    Digitale Medien
    Autoradiographic studies of 3H-dexamethasone uptake by immunocytochemically characterized cells of the rat pituitary (1977)
    Springer
    Cell & tissue research 182 (1977), S. 347-356 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pituitary ; Dexamethasone ; ACTH ; Autoradiography ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary 3H-Dexamethasone (10 μg/kg) was injected intravenously in adrenalectomized rats and after survival times of 5, 30, 60, and 180 min its uptake within the pituitary was studied by autoradiography. Radioactivity was concentrated in cell nuclei in the pars nervosa and pars distalis. Within the pars intermedia, only cells of the marginal zone were labeled. In the pars distalis, some cells showed a weak nuclear accumulation of radioactivity as early as 5 min after injection. The tissue radioactivity was nearly maximal at 5 min, and the proportion of radioactivity in nuclei reached a maximum of 60–70% by 30 min. In competition experiments, non-radioactive steroids (1 mg/kg) were injected 5 min before 3H-dexamethasone and sacrifice was 30 min later. Dexamethasone markedly diminished the nuclear accumulation in the pars distalis, but corticosterone and progesterone did not. In the pars nervosa, corticosterone and progesterone competed for nuclear uptake of 3H-dexamethasone, although less effectively than dexamethasone itself. Different cell types in the pars distalis were characterized by treating autoradiograms with an immuno-peroxidase bridge procedure. Cells treated with anti-ACTH 17–39 had the greatest nuclear concentration of radioactivity, and those stained with anti-TSH were least heavily labeled. Cells treated with antisera to GH, PRL, and hCG were moderately labeled.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219770
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  • 72
    Digitale Medien
    Digitale Medien
    Fine structure of capillaries in the conus papillaris of the limbless lizard, Ophisaurus apodus (Anguidae, Lacertilia) (1977)
    Springer
    Cell & tissue research 182 (1977), S. 421-424 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Lizard ; Eye ; Conus papillaris ; Capillaries ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The conus papillaris of Ophisaurus apodus consists of blood vessels and pigment cells. The capillary walls are formed by endothelial cells, scarce pericytes and basal laminae. The cell bodies are attenuated and the plasmalemma of their luminal and abluminal surfaces forms microvilli. The perivascular space is well developed, containing nerve fibers and their terminals. Similar localization and ultrastructure of avian pecten oculi and lacertilian conus papillaris suggest homology of these structures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219776
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  • 73
    Digitale Medien
    Digitale Medien
    A cell type in sponges involved in the metabolism of glycogen (1977)
    Springer
    Cell & tissue research 175 (1977), S. 523-539 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Sponge ; Gray cell ; Glycogen ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The gray cells of four orders of demosponges contain basophilic inclusions and glycogen. They are capable of synthesis and accumulation of glycogen and responsible for its transfer to sites of more intense metabolism (growth, bud, blastema). They do not occur in larvae; but all the phases of their differentiation from the flagellar cells of the larva have been demonstrated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00222416
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  • 74
    Digitale Medien
    Digitale Medien
    Excitatory synapses of blue crab gastric mill muscles (1977)
    Springer
    Cell & tissue research 177 (1977), S. 145-158 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Neuromuscular synapse ; Crustacean ; Ultrastructure ; Physiology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Physiological and ultrastructural studies were made of neuromuscular synapses in stomach muscles, especially two gastric mill muscles of the blue crab innervated by neurons of the stomatogastric ganglion. These muscles depolarized and contracted with application of glutamate, but not acetylcholine, whereas the dorsal dilator muscles of the pyloric region depolarized and contracted in acetylcholine, but not in glutamate. Large excitatory postsynaptic potentials (EPSP's) of 5–20 mV were recorded in the gastric mill muscles. At low frequencies of activation, individual synapses released on average about 2 quanta of transmitter for each nerve impulse. Facilitation of EPSP's after a single nerve impulse could be detected for at least 10 s. Synapses were found on enlarged terminals of the motor axon; their contact areas ranged from 0.2 μm2 up to 3 μm2. Both electron-lucent, round synaptic vesicles and dense-cored vesicles occurred near these synapses. A possible correlation between contact area of a synapse and output of transmitter, is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221078
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  • 75
    Digitale Medien
    Digitale Medien
    The ultrastructure of the mid-gut cells of Nasonia vitripennis (Walker) (Hymenoptera, Pteromalidae) (1977)
    Springer
    Cell & tissue research 177 (1977), S. 227-238 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Insects ; Nasonia vitripennis ; Mid-gut ; Morphometry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the mid-gut cells of female Nasonia vitripennis is described. The mid-gut consists of a uniform, single-cell epithelium. The cells of different gut regions were analysed using morphometric techniques in order to determine any differences in the components. The structure of the cells is described in the unfed animal, and after varying periods of feeding on host body-fluids. Tissues were sampled after 12 h and 24 h of feeding on host body-fluids and after 24 h feeding/24 h starvation. The cells were found to be complex and contain an organelle component that allows solute-transport and extensive lipid synthesis. A limited cytochemical analysis involving the lysosomal marker enzyme-acid phosphatase — and the respiratory enzyme — cytochrome oxidase was carried out.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00221084
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  • 76
    Digitale Medien
    Digitale Medien
    Structure and position of receptors within scales bordering the toes of gekkonids (1977)
    Springer
    Cell & tissue research 177 (1977), S. 325-330 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Reptilian scales ; Receptors ; Innervation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In gekkonids, the scales bordering the toes or the adjacent tissue possess subepidermal and intraepithelial receptors in addition to setae-bearing organs. The position of subepidermal lamellated corpuscles seems to be correlated with the size of the species. The larger the adult animal the more frequently is this type of receptor found laterally in the toe. This can be explained in connection with the vibration-sensitive function of lamellated receptors. Intraepithelial axon terminals were found close to the setae-bearing sensilla in one species only. They are surrounded by numerous tonofibrils and may function as receptors for mechanical (pressure-) stimuli.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220308
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  • 77
    Digitale Medien
    Digitale Medien
    Exocrine pancreas under experimental conditions (1977)
    Springer
    Cell & tissue research 177 (1977), S. 459-474 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Exocrine pancreas ; Isolated cells ; Cell membrane ; Tight junctions ; Gap junctions ; Ultrastructure ; Freeze-fracturing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The ultrastructure of the cell membrane and intercellular junctions was studied after isolation of exocrine pancreatic cells by tryptic digestion and mechanical treatment. The number and distribution of membrane associated particles does not change significantly when acinar cells in situ are compared to those after the isolation procedure. However, intercellular junctions undergo distinct alterations. Gap junctions in normal pancreatic cells are macular in shape and localized at the lateral parts of the cell membrane. In isolated acinar cells gap junctions are irregularly shaped, more extended, and frequently associated with tight junctions. Tight junctions form belt-like structures which are found to persist after isolation but subsequently become elongated and interrupted. Thus extensive macular areas of tight junctions develop. Further, the strands on the P-face and the grooves on the E-face of freeze-fracture replicas change in array, dissociate, and become loosely packed on large membrane areas. The present investigation shows that the intramembranous proteins of tight and gap junctions are mobile structures within the fluid membrane. The shape of their array is dependent on the form of the intercellular contact zone.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220607
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  • 78
    Digitale Medien
    Digitale Medien
    Isolation, characterization and localization of bovine adrenal medullary myosin (1977)
    Springer
    Cell & tissue research 178 (1977), S. 17-38 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Myosin ; Immunocytochemistry ; Adrenal medulla ; Exocytosis ; Secretion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Myosin was isolated in high purity from the bovine adrenal medulla by gel filtration and ion exchange chromatography. The purified myosin was analyzed by electrophoresis in gels containing SDS and found to contain a 200,000 molecular weight heavy chain and major light chains of molecular weights 20,000 and 17,000 in a 1∶1∶1 molar ratio. At high ionic strength the myosin had high Ca-ATPase and K-EDTA-ATPase activities and low Mg-ATPase activity. At low ionic strength, the Mg-ATPase was activated to a low level by rabbit muscle actin. The myosin was found to decorate F-actin in the absence, but not the presence of ATP. In low ionic strength solutions, the myosin assembled into characteristic bipolar filaments. The distribution of this myosin in the adrenal medulla and of cross-reacting myosin in several other bovine tissues was determined with the use of antimedullary myosin immunoglobulin G as a specific stain that was detected by direct and indirect immunofluorescence. In the medulla strong staining was seen between the chords of chromaffin cells indicating the presence of a highly muscular vasculature that may perform functions analogous to those of the myoepithelium of exocrine glands. The chromaffin cells showed weak positive staining around the nuclei and in a pattern radiating toward adjacent blood vessels. Cells of the inner zone of the adrenal cortex showed strong staining in the peripheral cytoplasm while cells in the intermediate and outer zones did not stain. In a blood smear, platelets and the cytoplasm of leukocytes stained strongly while erythrocytes did not stain. In striated muscle and the gray and white matter of the cerebrum only the capillaries and larger vessels stained. In the liver the phagocytic cells bordering vascular sinuses stained strongly while the hepatocytes were separated from one another by a 2 micron trilaminar band possibly representing the microfilament web surrounding the bile canaliculi and associated with junctional complexes. The results suggest that myosin is present in several highly differentiated, non-motile tissue cells where it may play a role in secretion or other specialized functions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00232821
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  • 79
    Digitale Medien
    Digitale Medien
    The development of innervation in the rat atrioventricular node (1977)
    Springer
    Cell & tissue research 178 (1977), S. 73-82 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Atrioventricular node ; Rat ; Innervation ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The problem of development of the innervation of the rat atrioventricular node has been investigated by electron microscopy. Nerve bundles appear in relation to the node as early as the second postnatal day and vesiculated axons are seen throughout the entire node by the fourth day. Intimate contacts between nodal cells, axons and terminal varicosities are frequently observed. Use of the 5-hydroxydopamine tracer technique has enabled the identification of both cholinergic and adrenergic axons. It is concluded that the node has a dual innervation although cholinergic endings far outnumber those classified as adrenergic on the sixth postnatal day. These results are quite different to earlier findings made at the light microscope level and the discrepancies are discussed with respect to the histochemical techniques used. The suggestion that nodal differentiation is induced by nerves is considered in relation to the differences in cholinesterase activity exhibited by nodal cells during normal development and following neonatal sympathectomy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00232825
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  • 80
    Digitale Medien
    Digitale Medien
    Quantitative dünnschicht-chromatographische Bestimmung von aromatischen Aminen nach der Remissionsmethode (1978)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 292 (1978), S. 381-384 
    Details
    ISSN: 1618-2650
    Schlagwort(e): Best. von Aminen, aromat. ; Chromatographie, Dünnschicht ; Remissionsmessung
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Es wird eine Methode zur quantitativen Bestimmung von aromatischen Aminen beschrieben. Diese werden dünnschicht-chromatographisch auf Kieselgel 60 F254 Fertigplatten in den Laufmitteln n-Propanol/Methanol/Wasser/Eisessig (65∶15∶15∶20; Vol.) oder n-Butanol/Wasser/Eisessig (66∶17∶17; Vol.) von den Begleitstoffen abgetrennt. Die getrennten Aminflecke werden entweder im Ultraviolett-Bereich oder nach Diazotierung im sichtbaren Bereich mit dem Chromatogramm-Spektralphotometer PMQ II nach der Remissionsmethode gemessen und anhand der auf derselben Platte aufgestellten Eichgerade ausgewertet. Die quantitative Bestimmung wird anhand der beiden Amine 5-Amino-2,4,6-trijod-isophthalsäurebis-(2,3-dihydroxy-propyl-N-methylamid) (I) und 2,4,6-Trijod-3-aminobenzoesäure (II) in Röntgenkontrastmittelpräparaten (RKP) demonstriert. Sowohl im UV- als auch im sichtbaren Bereich, läßt sich in 3000 μg RK-Säure (RKS) noch 0,1 μg freies aromatisches Amin, das sind 0,003%, bezogen auf die eingesetzte Menge RKS, mit einer maximalen relativen Standardabweichung von 4% bestimmen. Diese Methode ist spezifischer und empfindlicher als die der Diazotierung in Lösung.
    Notizen: Summary The aromatic amines are separated from impurities by thin-layer chromatography on silica gel 60 F254 precoated plates in the mobile solvents n-propanol/methanol/water/glacial acetic acid (65∶15∶15∶20; vol.) or n-butanol/water/glacial acetic acid (66∶17∶17; vol.). The separated amine spots are measured by the remission method by means of the TLC densitometer PMQ II, either in the u.v. region or, after diazotization, in the visible region, and evaluated on the basis of the linear calibration curve set up on the same plate. Quantitative determination is demonstrated by means of the two amines, 5-amino-2,4,6-triiodoisophthalic acid-bis-(2,3-dihydroxypropyl-N-methylamide) (I) and 2,4,6-triiodo-3-aminobenzoic acid (II), in radiopaque contrast media (RCM). Both in the u.v. and visible regions, it is still possible to determine 0.1 μg of free aromatic amine in 3000 μg of radiopaque contrast medium acid (RCA), or 0.003% in terms of the amount of RCA used, with a maximum relative standard deviation of 4%. This method is more specific and more sensitive than that of diazotization in solution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00481557
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  • 81
    Digitale Medien
    Digitale Medien
    Analyse von Desodorantien in kosmetischen Präparaten (1978)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 293 (1978), S. 135-137 
    Details
    ISSN: 1618-2650
    Schlagwort(e): Analyse von Desodorantien, Phenolderivaten in Kosmetika ; Chromatographie, Dünnschicht
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Phenolische Desodorantien in kosmetischen Präparaten lassen sich durch Umsetzung mit Echtrotsalz Al (Anthrachinondiazonium-chlorid-1) in wäßrig-alkalischer Lösung, Extraktion des gebildeten Azofarbstoffes mit einem organischen Lösungsmittel und anschließender Dünnschicht-Chromatographie schnell identifizieren. In den meisten Fällen ist die Abhängigkeit zwischen der Extinktion der Farbstofflösung und der eingesetzten Menge des betreffenden Desodorants linear, wodurch dann auch quantitative Bestimmungen möglich sind.
    Notizen: Summary Phenolic compounds, used as deodorants in cosmetic products can be identified quickly by reaction with anthraquinonediazonium chloride-1 (Echtrotsalz Al) in aqueous alkaline medium, extraction of the azo dye with an organic solvent and separation by thinlayer chromatography. The relation between the absorbance of the coloured solution and the concentration of the deodorant concerned is generally linear; in these cases quantitative determinations are always possible.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00486992
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  • 82
    Digitale Medien
    Digitale Medien
    Trennung und Nachweis von N-Heterocyclen auf CuSO4-imprägnierten Schichten (1978)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 291 (1978), S. 366-368 
    Details
    ISSN: 1618-2650
    Schlagwort(e): Nachw. von N-Heterocycl. Verbindungen ; Chromatographie, Dünnschicht ; CuSO4-imprägnierte Schichten, Fluorescenz
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Durch die charakteristischen Fluorescenzfarben und die Fluorescenz-Thermochromie der CuJ-Komplexe lassen sich N-Heterocyclen auf Chromatogrammen meist einwandfrei identifizieren. Eine wesentliche Vereinfachung wird durch die Verwendung CuSO4-imprägnierter Kieselgelschichten erreicht. Die Nachweisempfindlichkeiten insbesondere bei tiefer Temperatur ändern sich im Vergleich zur ursprünglichen Technik kaum.
    Notizen: Summary N-Heterocycles can usually be identified with certainty through the characteristic fluorescence colours and fluorescence-thermochromism of the CuI-complexes. The use of CuSO4-impregnated silica gel layers facilitates the procedure considerably, and scarcely reduces the sensitivity of detection, particularly at low temperature.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00464970
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  • 83
    Digitale Medien
    Digitale Medien
    TLC separation of some inorganic ions on p-toluidine impregnated layers (1978)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 292 (1978), S. 415-416 
    Details
    ISSN: 1618-2650
    Schlagwort(e): Trenn. von Anorgan. Ionen ; Chromatographie, Dünnschicht ; mit p-Toluidin imprägnierte Schichten
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00481570
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  • 84
    Digitale Medien
    Digitale Medien
    The connections of the sensory organ of Bellonci with the brain in isopoda (Crustacea) (1977)
    Springer
    Cell & tissue research 182 (1977), S. 61-72 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Organ of Bellonci ; Sensory organ ; Synapses ; Ultrastructure ; Crustacea
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Le pédoncule qui rattache l'organe de Bellonci des Isopodes au cerveau des Crustacés, a été étudié chez Sphaeroma serratum et Anilocra frontalis. Ce pédoncule se transforme progressivement, vers le cerveau, en un tractus ayant l'aspect d'un nerf. Il est alors formé par les pédicules issus du corps des cellules sensorielles de l'organe de Bellonci. Il se termine, au niveau de la medulla interne, par une zone d'aspect alvéolaire formée par les terminaisons dilatées des pédicules sensoriels. The authors are greatly indebted to Prof. J.J. Legrand, Director of the E.R.A. 230, Poitiers, France, for his support and critical reading of the manuscript We also thank Mrs C. Besse for her technical assistance, Mr. T. Bauvais and A. Martin, for photographic help, and Miss D. Decourt for typing the manuscript A ce niveau, trois types de connections ont pu être observés. Un premier est charactérisé par des synapses afférentes au cerveau avec, dans les terminaisons des pédicules sensoriels, des structures comparables aux rubans présynaptiques décrits par certains auteurs dans des photorécepteurs d'Arthropodes. Deux autres types comportent des fibres issues du cerveau, les unes avec de petites vésicules à contenu clair, les autres avec des vésicules plus grandes et à contenu moyennement dense aux électrons, fibres donnant des synapses efférentes aux cerveau avec l'organe de Bellonci. La fonction sensorielle de l'organe de Bellonci est confirmée sans que le rôle de l'organe puisse être précisé.
    Notizen: Summary The peduncle linking the organ of Bellonci with the brain was examined in Sphaeroma serratum and Anilocra frontalis. This peduncle, in its extension to the brain, becomes a nerve-like tract with bundles of pedicles originating from the sensory cell bodies located in the organ of Bellonci. It ends at the level of the medulla interna in an alveolar region resulting from the swelling of the sensory pedicle terminations. At this level three types of connections have been observed. The first is characterized by afferent synapses to the brain with, in the sensory pedicle endings, structures similar to the presynaptic ribbons noted by some authors in photoreceptors of arthropods. The two other types include nerve fibres originating from the brain, one with small electron lucent vesicles, a second displaying larger vesicles with a core of medium density. These fibres form efferent synapses to the organ of Bellonci. The sensory differentiation of the organ of Bellonci in Isopoda is confirmed but its true role is not specified.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00222054
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  • 85
    Digitale Medien
    Digitale Medien
    Fine structure of the eyes of orb-weavers, Argiope amoena L. Koch (Araneae: Argiopidae) (1977)
    Springer
    Cell & tissue research 182 (1977), S. 81-91 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Photoreceptor ; Arthropod ; Spider ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The anteromedial eye of the web-building spider, Argiope amoena has been examined with light and electron microscopy. The eye consists of a cornea, a lens, a vitreous body and a retina. The retina contains 400 to 500 bipolar photoreceptor cells and pigment cells which envelop the receptor cells. Microvilli extend laterally from the distal process of each receptor cell beneath the vitreous body. The microvilli interdigitate with those from neighboring processes to form rhabdoms. Multivesicular bodies occur in the rhabdomeric portion, and in an intermediate segment, between the rhabdomeric portion and the receptor cell body, are found mixed lamellar vesicular bodies and lamellar bodies. A single axon extends from the receptor cell. The site of origin of the axon from the cell varies depending on the location of the cell in the retina. The axon originates on the intermediate segment, or on the lateral surface or proximal end of the cell body. The axons join together in the postero-dorsal region of the eye and then extend to the first optic glomerulus as an ocellar nerve of about 3 mm in length. The pigment cells, whose cell bodies lie among those of the receptor cells or the axons, possess cytoplasmic prolongations which reach up to the vitreous body.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00222056
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  • 86
    Digitale Medien
    Digitale Medien
    Innervation of the cultured fetal rat pancreas (1977)
    Springer
    Cell & tissue research 182 (1977), S. 133-138 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Innervation ; Fetal rat islets ; Histochemistry ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The fetal rat pancreas, explanted at 18 days of gestation and cultured up to ten days, contains numerous acetylcholinesterase-positive neurons. These nerves usually appear in small ganglia although single nerve cells are encountered. The axons of these intrapancreatic nerves appear to terminate only in the islet tissue and not on any exocrine components of the expiant. It is concluded that the fetal rat pancreas contains an islet-specific group of cholinergic neurons.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00222061
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  • 87
    Digitale Medien
    Digitale Medien
    The coxal glands of geophilomorpha (chilopoda): Organs of osmoregulation (1977)
    Springer
    Cell & tissue research 182 (1977), S. 247-251 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Coxal organs ; Water transport ; Geophilomorpha ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The organs terminating at the coxal pores of the tug-legs of Geophilomorpha are not repugnatorial glands, but possess typical transport epithelia with deep apical and basal infoldings of the cell membranes, between which numerous large mitochondria are located. Many transport vesicles are found in the basal region but fewer in the apical cytoplasm. The apex is characterized by bundles of longitudinally oriented microtubules, sparse endoplasmic reticulum and free ribosomes. Single neurosecretory axons with synaptoid areas are scattered among the cells. It is suggested that the coxal organs have a diuretic function in moist habitats and an antidiuretic effect in arid environments. The “switch-over” is evidently controlled by a neuroendocrine mechanism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220593
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  • 88
    Digitale Medien
    Digitale Medien
    Cytoplasmic annulate lamellae in human spermatogenesis (1977)
    Springer
    Cell & tissue research 176 (1977), S. 235-242 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Annulate lamellae ; Spermatogenesis ; Ultrastructure ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Electron microscopic examination of normal human testicular tissue revealed annulate lamellae (AL) in the cytoplasm of primary spermatocytes and spermatids. AL of primary spermatocytes are encountered in the perinuclear region, parallel to the nuclear envelope and form single or multiple membranous profiles containing numerous annuli (500–600 Å in diameter) frequently associated with a fibrillar electron dense material. Spermatids contain numerous layers of AL either continuous with the nuclear envelope and caudal to the acrosome or peripherally positioned in the cytoplasm. Individual lamellae possess terminal dilations and display continuities with the endoplasmic reticulum. The interlamellar space in spermatid AL is entirely filled with a fine granular electron dense material. Additionally, the break-down of AL in spermatozoan residual bodies is indicated by a dilation of AL cisternae to form vacuoles following the dissolution of pore complexes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00229464
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  • 89
    Digitale Medien
    Digitale Medien
    Structural correlates of function in the “opercularis” muscle of amphibians (1977)
    Springer
    Cell & tissue research 175 (1977), S. 499-522 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Muscle ; Audition ; Ultrastructure ; Amphibian ; Evolution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary This study characterizes the fine structure of the “opercularis” muscles of selected frogs and salamanders (Genera: Hyla; Desmognathus; Ambystoma). The “opercularis” muscle originates on the shoulder girdle and inserts on the opercular plate in the fenestra ovalis of the otic capsule. Each of the three genera used exhibits one of the major gross dispositions of this muscle found in amphibians. In each case the “opercularis” muscle contains large numbers of tonic fibers: 80% in Hyla; 90% in Desmognathus; 45% in Ambystoma. These fibers correspond to the class-5 tonic fibers of Smith and Ovalle (1973). The remainder of the fibers in the “opercularis” correspond to those in the class-3 “phasic” of Smith and Ovalle. The muscle from which the “opercularis” is derived (levator scapulae in Hyla, cucullaris in Desmognathus) is comprised of fibers which correspond to the class-2 phasic fibers of Smith and Ovalle. The fiber composition of the “opercularis” indicates that it is constructed to sustain contraction over long periods of time. This composition is supportive of the functional role in audition proposed for the muscle by Lombard and Straughan (1974). Evidence is presented that indicates that fiber size may be body size dependent and thus is an inappropriate criterion of fiber type identification.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00222415
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  • 90
    Digitale Medien
    Digitale Medien
    Ultrastructure of the basiepithelial nerve plexus of the sea urchin, Centrostephanus longispinus (1977)
    Springer
    Cell & tissue research 175 (1977), S. 551-562 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Nerve plexus ; Vesicles ; Nerve cell bodies ; Ultrastructure ; Echinoids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The basiepithelial nerve plexus of the Echinoid, Centrostephanus longispinus, contains strands of nerve fibres, which measure between 0.1 and 2.0 μm in diameter. Nonciliated epithelial supporting cells do not contribute to the plexus. Within the fibres different vesicular inclusions are found. By means of serial sectioning the structure of multipolar cell bodies within the plexus could be demonstrated.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00222418
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  • 91
    Digitale Medien
    Digitale Medien
    Glycogen deposits in the pyloric gland of the ascidian Styela clava (Urochordata) (1977)
    Springer
    Cell & tissue research 176 (1977), S. 47-55 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Glycogen ; Pyloric gland ; Ascidian ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The pyloric gland of Styela clava contains large glycogen deposits that are digested by treatment with alpha amylase and depleted by 15 days starvation. The deposits are surrounded by cytoplasmic regions containing smooth endoplasmic reticulum and mitochondria. The cells also have rough endoplasmic reticulum, Golgi cisterns, lysosomes, microvilli, cilia, and lateral infoldings of the plasma membrane. The fine structure of the pyloric cells and the position of tubules between the absorptive epithelium and general circulation suggest that the gland functions as the vertebrate liver in carbohydrate metabolism. The pyloric cells of Styela do not appear to be excretory in a ‘renal’ sense, since there is no infolding of the basal plasmalemma and mitochondria are usually associated only with the glycogen deposits. However, a hepatic-like excretory role is consistent with current findings. In light of the phylogenic affinities of vertebrates and ascidians, it is possible that the pyloric gland is homologous to the liver.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220343
    Standort Signatur Erwartet Verfügbarkeit
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  • 92
    Digitale Medien
    Digitale Medien
    Ultrastructural differentiations in the developing follicle cortex of Locusta migratoria, with special reference to vitelline membrane formation (1977)
    Springer
    Cell & tissue research 185 (1977), S. 247-262 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Oogenesis ; Vitelline membrane ; Locusta migratoria ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Electron microscopic studies on developing follicles of Locusta migratoria show the vitelline membrane to be composed of two ultrastructurally distinguishable components: The vitelline membrane bodies (VMBs) and, in addition, fine granular material, cementing the VMBs together. VMBs form first in the oocyte-near zone within the oocyte-follicle cell space. Subsequently, the second vitelline membrane substance is secreted between the VMBs through apical protrusions of the follicle cells. The possible origin of the VMBs is discussed. Yolk uptake in Locusta seems to occur predominantly by pinocytosis. During oocyte development the oocyte membrane is enlarged by numerous microvilli and folds. In addition pinocytotic vesicles are pinched off. It is supposed that the latter loose their coat and eventually transform into large proteid yolk spheres.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220669
    Standort Signatur Erwartet Verfügbarkeit
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  • 93
    Digitale Medien
    Digitale Medien
    A freeze-fracture study of tight junctions in the pars convoluta and pars recta of the renal proximal tubule (1978)
    Springer
    Cell & tissue research 186 (1978), S. 121-133 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Proximal tubule ; Tight junctions ; Ultrastructure ; Electron microscopy ; Freeze fracturing
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The morphology of tight junctions of the renal proximal tubule was studied comparing the pars convoluta and pars recta of rat, golden hamster, rabbit, cat, dog and tupaia. Though some interspecies variations were observed, the convoluted portions of the proximal tubules revealed quite uniformly very leaky tight junctions with mainly 1–2 strands. Along the whole proximal tubule of the rabbit kidney including the pars recta only minor differences of the zonulae occludentes were found. By contrast, the tight junctions of the pars recta in other species were much more elaborate, especially in cat and tupaia, having up to 6 strands and an overall depth of more than 150 nm. The implications of these findings are discussed with special regard to the functional differences between the pars convoluta and pars recta of the proximal tubule.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00219659
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  • 94
    Digitale Medien
    Digitale Medien
    Exocrine pancreas under experimental conditions (1978)
    Springer
    Cell & tissue research 186 (1978), S. 227-240 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pancreas (rat) ; Pancreatic duct ligation ; Cell membrane ; Intercellular junctions ; Ultrastructure ; Freeze fracture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Exocrine pancreatic tissue was investigated during various intervals after pancreatic duct ligation. Concomitant to the increase of the intraluminal pressure, alterations are found in the arrangement of the luminal membrane surface and the zonulae occludentes of the acinar cells. The zonulae occludentes exhibit a disarrangement of their strands. The number of strands diminishes and small interruptions as well as large discontinuities of the strands are observed in most regions of the acinar cells. Furthermore, gap junctions are found very infrequently between acinar cells. The ultrastructural alterations of the zonulae occludentes suggest a gradual adaptation to the increasing unilateral pressure. However, a leakage of the paracellular permeability barrier occurs which contributes to the known shunt between the compartments of the pancreatic juice and the interstitial space following pancreatic duct obstruction. The present investigation is a further example of alterations in the paracellular permeability and intercellular communication of epithelial cells under pathological conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00225533
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  • 95
    Digitale Medien
    Digitale Medien
    Localization of thyrotropin (TSH) in the dog pituitary gland (1978)
    Springer
    Cell & tissue research 186 (1978), S. 399-412 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Pituitary gland ; Dog ; Pars distalis ; Thyrotropin (TSH) ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Using the immunoperoxidase technique and antisera to the specific beta (β) subunits of bovine and rat TSH1, selective immunocytochemical staining was localized in a specific cell population in the pars distalis of the dog pituitary gland. These TSH cells were found to be positive to aldehyde fuchsin, alcian blue, periodic acid-Schiff (PAS) and aniline blue. With the performic acidalcian blue (pH 0.2) -PAS-orange G procedure these cells stained blue-purple, demonstrating FSH/LH cells (blue or turquoise), ACTH/MSH cells (redpurple) and PRL cells (orange-red). The TSH cells were further differentiated from other functional cell types of the pars distalis on the basis of their typical cytological features, intraglandular distribution and by immunocytochemical double staining. In the pars distalis of adult male dogs the TSH cells were mostly shown to be smaller in size and less numerous than in bitches in the anestrous phase of the sexual cycle. Moreover, cytological alterations in the immunoreactive thyrotrophs in the pituitary of male and female dogs generally paralleled the spontaneous changes in thyroid function associated with thyroid atrophy and/or pituitary insufficiency, and thyroid hyperplasia or goiter. In conclusion, because of their specificity and high potency, the antisera to the β-subunits of bovine and rat TSH represent an effective tool for the selective immunocytochemical localization of TSH in the dog pituitary. This allows the study of the morphology and function of TSH cells under different physiological, pathological and experimental conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00224930
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  • 96
    Digitale Medien
    Digitale Medien
    Fine structure of the eyes of orb-weavers, Argiope amoena L. Koch (Aranea: Argiopidae) (1978)
    Springer
    Cell & tissue research 186 (1978), S. 435-452 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Photoreceptors ; Arthropod ; Spider (Argiope amoena) ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The anterolateral eye, the posterolateral eye and the posteromedial eye of the web-building spider, Argiope amoena have been examined by light and electron microscopy. The dioptric apparatus of all three eyes is similar in structure, and consists of a cornea, a lens and a vitreous body. The retina contains monopolar receptor cells, the cell bodies of which are present beneath the vitreous body in all three eyes. Proximal processes of the receptor cells form rhabdoms beneath the cell body layer and then extend toward the first optic glomerulus as an ocellar nerve. Two distinct patterns of retinal organization are present in the three eyes. In one type the rhabdomic layer of the retina is backed by a pigmented layer. In the other type the rhabdomic layer is backed by a tapetal reflecting layer. Rhabdomic structure and cytoplasmic inclusions of the receptor cells differ greatly between the two types. The anterolateral eye possesses a single type of retina with the rhabdoms backed by the tapetum. Both the posterolateral and the posteromedial eye are similar in structure, each possessing beneath the common dioptric apparatus retinae of both types.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00224933
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  • 97
    Digitale Medien
    Digitale Medien
    Ultrastructure of the subfornical organ of the Japanese quail, Coturnix coturnix (1978)
    Springer
    Cell & tissue research 188 (1978), S. 19-33 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Subfornical organ ; Circumventricular organ ; Coturnix quail ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The structure of the subfornical organ (SFO) of the Japanese quail has been studied by light and electron microscopy. The SFO is a small semiglobular bulge in the midline on the rostrodorsal wall of the third ventricle between the anterior commissure and tela choroidea. The organ consists of three main parts, anterior stalk, the corpus and the posterior stalk. The anterior stalk is covered by ependymal cells with a few cilia, but the corpus and posterior stalk are characterized by a distinctive lack of cilia and by flat or bulging cell surfaces, which have the appearance of cobble stones. The large bulbous protrusions in the ependymal surface of the posterior stalk suggest a secretory function into the ventricle. In the subependymal layer, there are a few parvocellular neurons that contain small mitochondria, moderately developed Golgi apparatus, lysosomes, dilated cisternae of rER and a few dense-cored granules of 100–120 nm in diameter. They appear to be secretory in nature. Two types of glial cells occur in the subependymal and internal layers. One is small and spindle-shaped with a dense nucleus and elongated cytoplasmic processes; it may be microglial. The other is a small polygonal cell with rounded nucleus and clear cytoplasm containing bundles of filaments; it may be a protoplasmic astrocyte. The neuropil contains three types of axons. The first contains dense-cored granules, 80 nm in diameter, and clear vesicles, 40–60 nm in diameter and is involved in axosomatic synapses. The second type contains dense granules, 120 nm in diameter, and clear vesicles, 40–80 nm in diameter, and shows axodendritic synapses. The third contains peptidergic granules about 100–120 nm in diameter and seems to belong to the organ-specific nerve cells. These axons terminate at the perivascular space of the blood capillaries, suggesting secretion into the blood.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220512
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  • 98
    Digitale Medien
    Digitale Medien
    Immunocytochemical identification of an LHRH-producing system originating in the preoptic nucleus of the duck (1978)
    Springer
    Cell & tissue research 188 (1978), S. 99-106 
    Details
    ISSN: 1432-0878
    Schlagwort(e): LHRH-neurosecretion ; Avian hypothalamus ; Vasotocin neurosecretion ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A fluorescent technique applying specific LHRH and vasotocin antisera was used for the immunocytochemical localization of the respective neurosecretory systems in the hypothalamus of gonadectomized, testosteronetreated and/or serotonin injected male domestic ducks. An immunoreactive (IR) LHRH-producing system, with perikarya located in the preoptic nucleus, could be traced through the ventral hypothalamus down to the external layer of the rostral and caudal ME, in close vicinity to the hypophysial portal system. An IR-vasotocin system originating in the paraventricular and supraoptic nuclei ran through the ventral hypothalamus, but terminated in (i) the external layer of the rostral ME, and (ii) in the posterior lobe of the hypophysis.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220517
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  • 99
    Digitale Medien
    Digitale Medien
    Immunocytochemical study of the hypothalamo-neurohypophysial system (1978)
    Springer
    Cell & tissue research 188 (1978), S. 119-132 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Neurophysin ; Paraventricular nucleus ; Supraoptic nucleus ; Sheep ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An antiserum cross-reactive against ovine neurophysins-I-II and -III has been used in conjunction with the immunoperoxidase histochemical procedure to localize the cells of the sheep paraventricular (PVN) and supraoptic nuclei (SON). In order to describe the topographical distribution of the SON and PVN a study was made on the serial sections cut (a) transversely from rostral to caudal positions and (b) sagittally from lateral to medial positions of the hypothalamus. The cells of the SON, when examined in the transverse aspect, extended approximately 1900 μ caudally and when examined in the sagittal plane were contained within a lateral-medial distance of 4830 μ. In each case the SON cells lay adjacent to the optic chiasm. As sections were cut transversely, the cells of the PVN first appeared in a rostral position defined as 0 μ and close to the ventral lining of the third ventricle. This general ventral and ventro-lateral distribution of cells maintained up to a caudal distance of approximately 840 μ. From positions 1260–2310 μ there was a dramatic dorsal shift of the PVN cells which by this time had also extended laterally. The total rostral-caudal distance occupied by the PVN cells was 3150 μ. That the lateral-medial distance occupied by the PVN was small (1050 μ) was determined on examining the magnocellular nuclei in sagittal section.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00220519
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  • 100
    Digitale Medien
    Digitale Medien
    Origin of the glial processes responsible for the spontaneous postnatal phagocytosis of boutons on cat spinal motoneurons (1978)
    Springer
    Cell & tissue research 189 (1978), S. 203-217 
    Details
    ISSN: 1432-0878
    Schlagwort(e): Astrocytes ; Development ; Phagocytosis ; Neuroplasticity ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Previous studies have demonstrated that astrocyte processes are responsible for a spontaneously occurring phagocytosis of boutons on cat spinal motoneurons during the second postnatal week. In the present investigation, the astrocytes and the astrocyte processes in contact with the motoneurons were studied qualitatively and quantitatively during the early postnatal period. It could be concluded that the cells responsible for the phagocytosis of boutons are immature astrocytes. These cells were present not only during the period of phagocytosis but also prior to this period. The type of process responsible for the phagocytosis was present not only during the period of phagocytosis but also prior to and after that period although the relative contribution of such processes to the glia-covered membrane area of the motoneurons was reduced in the older animals. On the basis of these results, the possible specificity of the immature astrocyte as the element responsible for the phagocytosis of boutons during normal development is discussed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00209270
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