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  • 1
    ISSN: 0012-1606
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0248-4900
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0248-4900
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 96 (1969), S. 418-436 
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé L'évolution de l'ultrastructure de la cellule épithéliale mammaire de la Lapine est décrite au cours de: L'apparition des phénomènes sécrétoires qui prennent place normalement pendant le premier tiers de la gestation des Lapines primipares. La lactogénèse expérimentale produite par des injections de prolactine à des Lapines pseudo-gestantes. L'ultrastructure de la cellule mammaire de Lapine en sécrétion active (lactation) se distingue de celle des cellules inactives pour la sécrétion (début de la gestation et pseudogestation) par: le développement considérable de l'ergastoplasme organisé en lamelles parallèles ou concentriques; l'hypertrophie de l'appareil de Golgi; la présence de granules protéiques inclus dans des vacuoles d'origine golgienne au sein d'un cytoplasme hypertrophié, celle des gouttelettes lipidiques étant moins indicatrice d'un état d'activité sécrétoire. L'induction de la sécrétion lactée au cours de la gestation normale ou à la suite de l'injection de prolactine, conduit à des modifications ultrastructurales de la cellule mammaire qui se caractérisent principalement par le développement progressif des systèmes membranaires ergastoplasmiques, qui est déjà net entre 12 et 24 heures et aboutit le 3e jour de l'administration hormonale à des images se rapprochant de celles d'une cellule de glande mammaire en lactation. La formation d'un important réticulum endoplasmique auquel est liée la majorité des ribosomes, ainsi que le développement des citernes et vacuoles golgiennes, paraissent ainsi sous le contrôle de la prolactine. Nous discutons enfin de la signification de l'existence transitoire dans les premiers stades de la lactogénèse d'une organisation vacuolaire de l'ergastoplasme.
    Notes: Summary The ultrastructural development of the rabbit epithelial mammary gland cell is described during: The appearance of secretory phenomena usually occuring in primiparous rabbits in the last third of pregnancy. Experimental lactogenesis induced by injecting pseudopregnant rabbits with prolactin. The ultrastructure of the active secretory (lactating) rabbit mammary gland cell is distinguished from that of inactive epithelial cells (beginning of pregnancy or pseudo-pregnancy) by: a considerable development of the ergastoplasm organized in parallel or concentric lamellae; hypertrophy of the Golgi apparatus; the presence of protein granules included in vacuoles of Golgian origin in the middle of hypertrophied cytoplasm. The presence of lipid droplets is less indicative of an active secretory state. The induction of milk secretion during normal gestation or after a prolactin injection produces ultrastructural modifications in the mammary gland cell which are characterized by progressive development of the ergastoplasmic membrane system. This transformation becomes evident between 12–24 hours and on the third day of hormonal administration resembles that of the lactating mammary gland. The formation of a large endoplasmic reticulum to which the majority of ribosomes are bound and the development of cisterns and Golgi vacuoles appear under the influence of prolactin. The signification of the temporary existence, during the early stage of lactogenesis, of a vacuolar ergastoplasmic organization, is discussed.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 161 (1975), S. 329-341 
    ISSN: 1432-0878
    Keywords: Spermatozoa ; Boar, bull, ram ; Surface ultrastructure ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé La morphologie comparée des spermatozoïdes éjaculés de Verrat, Taureau et Bélier a été étudiée au microscope à balayage. Le sperme lavé est fixé dans le glutaraldéhyde ou le mélange acide picrique-formaldéhyde-glutaraldéhyde. Les échantillons sont le plus souvent désséchés par la méthode du point critique (Fréon) sur un filtre et aussi dans l'air sur une lamelle de verre. La tête des spermatozoïdes de ces trois espèces présente la même forme en pagaie aplatie formée de trois régions principales: les deux segments, antérieur, entouré d'un épaississement marginal, et équatorial de l'acrosome et la région postacrosomique. La plupart des differentiations de la lame postacrosomique décrites en microscopie électronique à transmission sont visibles à travers la membrane plasmique, particulièrement après dessication à l'air. La morphologie superficielle du cou et des différentes parties du flagelle est aussi observable. Des différences spécifiques sont mises en évidence: chez le verrat seulement, par exemple, la surface de l'acrosome apparaît granuleuse, et aucune bordure antérieure dentelée de la lame postacrosomique n'est visible. La microscopie à balayage permet d'observer les grands traits et de fins détails de la morphologie superficielle d'un échantillon de sperme et aussi d'étudier les effects de traitements sur des spermatozoïdes (congélation, extraction de l'acrosome).
    Notes: Summary The comparative ultrastructure of ejaculated boar, bull and ram spermatozoa is studied by scanning electron microscopy. After washing, the spermatozoa are fixed in glutaraldehyde or in picric acid-formaldehyde-glutaraldehyde mixture. Samples are prepared either by critical point drying (Freon) on Millipore filters or by air drying on glass cover slips. In all the species studied, three regions may be distinguished in the paddle-shaped head of the sperm: an anterior segment (surrounded by the marginal thickening) and an equatorial segment constituting together the acrosome, and the postacrosomal region. Most of the feature of the postacrosomal lamina described in transmission electron microscopy are visible through the plasma membrane, particularly after air drying. The surface morphology of the neck and of the different segments of the flagellum is also evident. Some species differences are encountered, e.g. rough surface of acrosome and absence of serrations in postacrosomal lamina of boar spermatozoa only. The techniques employed result in good general morphology and fine resolution of surface detail of the sperm samples; they also permit analysis of spermatozoa treated by freezing or submitted to acrosomal extraction.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 17 (1987), S. 35-42 
    ISSN: 0148-7280
    Keywords: zona pellucida ; autoradiography ; sperm binding ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rabbit spermatozoa were labeled predominantely in their acrosomal glycoproteins by 1-3H-glucosamine during spermiogenesis. Ova fertilized in vivo by spermatozoa labeled 22 days earlier were analyzed by fine-structure autoradiography for the localization of the label. The latter was found associated with 1) the fused membranes of the acrosomal cap remaining on the zona pellucida surface, 2) the material released on the zona surface after the acrosome reaction and possibly detectable after tannic acid fixation, 3) the equatorial segment of the sperm head and the preequatorial swellings, and 4) other sperm components, eg, the sperm tail. No labeling, on the other hand, was detected on the denuded leading edge of spermatozoa found either in the penetration slit or in the perivitelline space. Our observations suggest the involvement of acrosomal glycoproteins in different mechanisms of sperm/zona pellucida interaction but are not in favor of a major role of (enzymatic) glycoproteins bound to the inner acrosomal membrane during the penetration of the zona pellucida.
    Additional Material: 2 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 3 (1980), S. 141-148 
    ISSN: 0148-7280
    Keywords: cow blastocysts ; zona pellucida ; stability and location of antigenic material ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Labeling of the zona pellucida of cow blastocysts with zona-specific anti-serum shows that antigenicity is unaffected by abnormal cleavage, in vitro culture, or frozen storage. The uniform labeling in thin sections indicates that the zona pellucida is homogeneous antigenically. Heavier labeling of the inner and outer surfaces of the zona pellucida in thick sections appers to be due to greater porosity of these regions, in which the zona material becomes highly dispersed, or even partly solubilized, thereby permitting the formation of an antigen-antibody matrix.
    Additional Material: 12 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 40 (1995), S. 305-310 
    ISSN: 1040-452X
    Keywords: Fibrillarin ; Nucleolin ; Immunocytochemistry ; Cleavage-stage embryo ; Mouse ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The localization of fibrillarin and nucleolin in the nuclei of mouse two-cell, four-cell, and eight-cell embryos has been studied using immunofluorescent staining with specific antibodies. In all of these cleavage stages, both antigens were associated exclusively with the peripheral region of the nucleolus precursor bodies (NPBs). The original speckled fluorescent staining pattern in the early two-cell stage was progressively changed into a continuous fluorescent-positive layer localized in the cortex of the NPBs in the four-cell embryos. The compact central area of NPBs was never stained. Both proteins were colocalized in the same substructures of developing nucleoli. In order to analyze the interaction of chromatin, with NPBs, DNA structures were specifically immunolbelled. At the time of resumption of nucleolar transcription (in the two-cell mouse embryo), DNA was detected at the periphery of, but not penetrating into, NPBs. Our results confirm the view that the cortical region of NPBs could represent a nucleolonemal area involved in the resumption of nucleolar transcription in the early mouse embryo. © 1995 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 41 (1995), S. 274-274 
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 1 (1989), S. 79-90 
    ISSN: 1040-452X
    Keywords: Cleaving embryo ; RNA synthesis ; DNA distribution ; Cattle ; Nucleogenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Eight-cell cow embryos were isolated and cultured in vitro in a medium enriched with 200 μCi of [5-3H]uridine for 20 min. Epon ultrathin sections of the embryos were investigated for the nucleolar morphology and for the appearance and localization of the sites of [5-3H]uridine incorporation by means of electron microscopic autoradiography. In addition to this, a general pattern of replicated embryonal DNA distribution was revealed by [methyl-3H]thymidine incorporation and light microscopic autoradiography.The essential phases of the transformation of the small nucleous precursor body (NPB) into a vast, functionally fully active nucleolus, characterized by typical nucleolar substructural components, are taking place within the eight-cell stage. This process differed in its morphology from the nucleologenetic process in early embryogenesis of other mammals, especially of that in the mouse.The first sign of NPB, transformation was the appearance of a large central vacuole followed later on by perinucleolar chromatin penetration into NPB, documented by both morphology and [3H]thymidine autoradiography. In some cases, concentration of dense fibrillar material forming clumps or stalks was seen in the central vacuole.The following rapid nucleolar development was characterized by the formation of secondary vacuoles concomitant with the onset of [5-3H]uridine incorporation into the dense fibrillar component and with the appearance of the first granules in the otherwise fibrillar structure of the nucleolus. During the late eight-cell stage, the still-rounded nucleolus developed features of a reticulated nucleolus known from somatic cells intensively synthesizing rRNA: a dense fibrillar component with associated labeling encircling fibrillar centers and a well-developed granular component. The labeled dense fibrillar component was observed mostly in the central area of the nucleolus; early embryonic NPB dense fibrous material not involved in transcription was disappearing rapidly. At the transition to the 16-cell stage the nucleoli lost their rounded shape because of the accumulation of a large amount of granular component, and they occupied a considerable part of the nucleus. In conclusion, the appearance of the nucleolar vacuole in eight-cell cow embryo is the starting point for following morphogenetic events linked with the onset of transcription.
    Additional Material: 14 Ill.
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