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  • Rat  (80)
  • Springer  (80)
  • AGU (American Geophysical Union)
  • American Institute of Physics
  • Institut für Polarökologie Kiel
  • Lipsius & Tischer
  • Springer Nature
  • Taylor & Francis
  • Western Atlas International
  • Wiley
  • 2020-2022
  • 1985-1989  (80)
  • 1890-1899
  • 1987  (80)
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  • Springer  (80)
  • AGU (American Geophysical Union)
  • American Institute of Physics
  • Institut für Polarökologie Kiel
  • Lipsius & Tischer
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  • 2020-2022
  • 1985-1989  (80)
  • 1890-1899
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 24 (1987), S. 260-271 
    ISSN: 1432-1432
    Keywords: Mouse ; Rat ; Two-dimensional electrophoresis ; Quantitative variability of proteins ; Qualitative variability of proteins ; Protein classes ; Membrane proteins ; Organ-specific proteins ; Regulatory genes ; Speciation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Proteins of membranes and cytosols were extracted from the livers and brains of mice (inbred strain DBA/6J) and rats (inbred strain DA/Han) and separated by two-dimensional electrophoresis (2-DE). The 2-DE patterns were compared with regard to qualitative (spot position) and quantitative (spot intensity) characteristics of the proteins of these two species. The following results were obtained: (1) Brain had more (higher percentage) conservative proteins (proteins found in both mice and rats) than liver; (2) plasma membranes had more conservative proteins than the cytosols; (3) organ-unspecific proteins contained more conservative proteins than relatively organ-specific proteins; (4) the pattern of distribution of genetic variability among different classes of proteins represented by findings 1–3 was the same for the qualitative and quantative characteristics of the proteins; and (5) some observations indicated that quantitative variability occurred more frequently among proteins than did qualitative variability. Our conclusion is that regulatory sequences in the DNA (regulatory genes) are subjected to functional constraints that differ in strength among different classes of proteins by the same ratios as the constraints acting on the structural genes. The overall effect of the selective pressure is, however, less stringent for regulatory genes than for structural genes. The results obtained here by comparing two different species are very similar to previous results we obtained by studying different subspecies (inbred strains of the mouse). From this finding arises a new concept: the study of molecular evolution on the basis of different classes of proteins. Our results were compared with data from the literature that were obtained in part from studies on cultured cells. The comparison suggested that cultured cells have lost their tissue-specific proteins, and so generate predominantly extremely conservative proteins.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European journal of nutrition 26 (1987), S. 43-51 
    ISSN: 1436-6215
    Keywords: Dietary protein ; Vitamin A ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Es wurde der Einfluß von Qualität und Quantität von Nahrungsproteinen auf die Verteilung einer einzigen massiven Dosis von Vitamin A in verschiedenen Organen wachsender Wistar-Ratten untersucht. Die Untersuchungen wurden mit Casein- und Bengal-Gram-Diäten mit 20 % und 10 % Proteingehalt und auch mit radioaktiv markiertem Retinylacetat durchgeführt. Die Ergebnisse zeigen, daß die Leberspeicherung sowohl von Vitamin A aus der Nahrung als auch die einer einzigen starken Vitamin-A-Gabe (20 000 I.U.) stark herabgesetzt war bei Ratten, die nach der Bengal-Gram-Diät gefüttert wurden, verglichen mit Ratten, die auf Casein-Diät gesetzt waren. Im Gegensatz zur Leberspeicherung ist das Vitamin-A-Niveau im Plasma in allen Gruppen vergleichbar. Füttern niedriger Protein-Qualität reduzierte die Gewebeverteilung von [3H]-Retinylacetat sowohl bei Kontrollratten als auch bei solchen, denen eine massive Dosis Vitamin A gegeben wurde. Diese Untersuchung läßt vermuten, daß sowohl schlechte Qualität als auch unzureichende Mengen von Nahrungsproteinen nachteilige Einflüsse auf den Vitamin-A-Zustand wachsender Ratten haben.
    Notes: Summary The influence of the quality and the quantity of dietary proteins on the distribution of a single massive dose of vitamin A in various organs of growing Wistar strain rats has been studied by using casein and bengal gram diets at 20 % and 10 % protein levels. The distribution of [3H]-retinyl acetate in various tissues was also investigated in these dietary conditions. The results show that the hepatic storage of dietary as well as a single massive dose (20,000 I.U.) of vitamin A was profoundly decreased in the rats fed on bengal gram diets as compared to those fed on casein diets. Regardless of hepatic stores, the plasma vitamin A levels were comparable in all the groups. Feeding of low quality of protein reduced the tissue distribution of [3H]-retinyl acetate in control as well as rats given a massive dose of vitamin A. This study suggests that both the poor quality and the inadequate quantity of dietary protein are detrimental influences on the vitamin A status of the growing rats.
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  • 3
    ISSN: 1432-0878
    Keywords: Cholecalcin (vitamin D-dependent calcium-binding protein) ; mRNA ; Uterus ; In situ hybridisation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The molecular cloning of a cDNA fragment synthesised from rat duodenal mRNA coding for cholecalcin (calbindin), a 9000 Mr vitamin D-induced calcium-binding protein (CaBP), has been previously described. DNA/RNA hybridisation assays have been used to examine CaBP mRNA production in the uterine horns and duodena of pregnant (21 day) rats using the cloned CaBP cDNA. Northern hybridisation studies showed that the 32P cDNA sequence hybridised to a single 500–600 nucleotide species in both the uterus and the duodenum, thus demonstrating identical CaBP mRNA processing in both tissues. Dot blot hybridisation studies showed that the CaBP mRNA concentration was greatest in the duodenum while that of the uterine horns was about 10% of the duodenal level. The observed differences in CaBP mRNA levels correlate well with the in vivo CaBP concentrations. In situ hybridisation histochemistry using 3H cDNA revealed that CaBP mRNA visualised by silver grains was found in all the parts of the endometrium and the myometrium. However, CaBP mRNA was more concentrated in the outer and inner muscular fibres and in the luminal cells of the endometrium than in the stroma cells. These results demonstrate that the CaBP gene is expressed in specific cells of the rat uterus.
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  • 4
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Aminoglutethimide ; Corticosterone ; Morphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of a 7-day administration of aminoglutethimide (AG) on the adrenal zona fasciculata were examined in “normal” and dexamethasone/ACTH-treated rats. There was a 70–74% decrease in the concentration of corticosterone in blood, but no conspicuous qualitative changes suggesting cell degeneration occurred. Morphometry showed that AG induced a significant hypertrophy of the zona fasciculata and its parenchymal cells only in “normal” animals, which was due to an increase in the volume of the mitochondrial compartment and to proliferation of the smooth endoplasmic reticulum. This response to AG was considered to be non-specific and mediated by the enhanced secretion of ACTH following the decrease in the blood level of corticosterone. AG administration significantly increased the volume of the lipid-droplet compartment and the number of intramitochondrial lipid-like inclusions in both groups of animals. These changes were interpreted as the morphological counterpart of the AG-induced block of cholesterol utilization in steroid synthesis.
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  • 5
    ISSN: 1432-0878
    Keywords: Astrocytes ; Ependymal cells ; Circumventricular organs ; Tight junctions ; Orthogonal arrays of particles ; Freeze-fracturing ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ependymal cells in the ventricular wall and in several circumventricular organs of the rat were compared by means of freeze-fracturing. In principle, tight junctions and orthogonal arrays of particles (OAP) do not coexist in the cells bordering the ventricular wall: (1) Ordinary ependymal cells of the rat possess OAP and are devoid of tight junctions. (2) Epithelial cells of the rat choroid plexus are connected by tight junctions; OAP are lacking here. In some cases, however, tight junctions and OAP coexist in the same cell. In the boundary zone between choroid plexus and ependyma of the rat, the density of OAP is very low, whereas the tight junctions are well developed. In the subfornical and the subcommissural organ (SCO) of the rat both structures are poorly developed; in the SCO they occur segregated in different membranous areas. An overview of the literature confirms that tight junctions and OAP mostly exclude each other. The possibility that in astrocytes and ependymal cells tight junctions may have been replaced by OAP during phylogeny is briefly discussed.
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  • 6
    ISSN: 1432-0878
    Keywords: Teeth ; Dental pulp ; Periodontium ; Neurofilament protein ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of nerve fibers in molars, periodontal ligament and gingiva of the rat shows a complex pattern. Decalcified material including the alveolar bone was sectioned in three different planes and stained by means of immunohistochemistry for detection of the neurofilament protein (NFP); the immunoreactive neural elements were clearly visualized in three-dimensional analyses. NFP-positive nerve fibers formed a subodontoblastic plexus in the roof area of the dental pulp; some of them entered the predentin and dentin directly through the dentinal tubules. This penetration was found mainly in the pulp horn, and was limited to a distance of about 100 μm from the pulpo-dentinal junction. In the periodontal ligament, NFP-positive nerve fibers were found densely distributed in the lower half of the alveolar socket. Two types of nerve terminals were recognized in the periodontal ligament: free nerve endings with tree-like ramifications, and expanded nerve terminals showing button- or glove-like shapes. The former tapered among the periodontal fibers, some even reaching the cementoblastic layer. The latter were located, frequently in groups, within the ligament restricted to the lower third of the alveolar socket. A well-developed plexus of NFP-positive nerves was revealed in the lamina propria of the free gingiva, the innervation being denser toward the epithelium of the gingival crevice. The characteristic distribution of NFP-immunoreactive nerve fibers revealed in this study is discussed in relation to region-specific sensations in the teeth and surrounding tissues.
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  • 7
    ISSN: 1432-0878
    Keywords: Epididymis ; Ductus deferens ; Myosin ; Actin ; Fibronectin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The postnatal maturation of regions of the epididymis and intragonadal segment of the deferens duct was studied in the rat by light-and transmission electron microscopy. Maturation of the genital duct starts in the distal cauda epididymidis and ductus deferens after one week of life, and one week later, in the more cranial segments of the epididymis. Epithelial principal cells and peritubular contractile cells are structurally mature 35 days after birth. The synchronous changes of these cells indicate that the same factors control their postnatal maturation. The epithelial principal cells obtain an endocytotic apparatus and long stereocilia, whereas peritubular cells acquire contractile features. These changes are associated with a progressive increase in the immunoreaction for smooth muscle actin in both cell types. Smooth muscle myosin is detected in the apical region of the epithelial cells and the peritubular cell cytoplasm by day one of postnatal development. The differentiation of contractile cells in the wall is accompanied by progressive organization of the pericellular matrix into a continuous basement membrane. Although fibronectin is visible at birth, it is gradually removed from the tubule wall.
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  • 8
    ISSN: 1432-0878
    Keywords: Cardiac muscle cells ; Extracellular matrix ; Collagen fibers and filaments ; Immunohistochemistry ; Rat ; Hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology, composition, and function of struts that interconnect the lateral surfaces of cardiomyocytes were examined in the hearts of rats and hamsters. Methods included brightfield and fluorescent light microscopy, secondary and backscatter scanning electron microscopy, and transmission electron microscopy in conjunction with silver stain, cationic dye, and antibody to type-I collagen. These studies reveal a twisted, beaded appearance and a complex substructure of collagen fibrils embedded in a ground substance that has a positive reaction with cationic dye. A hierarchy of patterns of branching and attachment was seen among intercellular struts ranging in diameter from 0.1 μm to several urn. The hypothesis that struts tether not only the surfaces but the contractile lattices of laterally adjacent myocytes is supported by the following: (a) the attachments of struts to the collagen weave of the sarcolemma, often lateral to the level of Z bands, (b) the presence of collagen type I in a composite material arrangement, (c) the relative dispositions and configurational changes of struts and myocyte surfaces in various physiological states and induced, non-physiological perturbations of cardiac muscle, (d) the corrugated sarcolemmas with infoldings near Z bands, and (e) the continuity of intracellular filaments from Z bands to the inner aspect of the sarcolemma in relaxed and contracted myocytes. Implications of struts acting as tethers and sites for storage of energy in the motions of myocytes during the cardiac cycle are discussed.
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  • 9
    ISSN: 1432-0878
    Keywords: GABA-treatment ; Superior cervical ganglion ; Synaptic plasticity ; Morphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The superior cervical ganglion (SCG) of adult rats was exposed to γ-aminobutyric acid (GABA) by means of long-term microapplication. Serial sections were cut from GABA-treated and control ganglia, and subsequently the fine structure of individual synapses was investigated. The quantitative analysis of structural parameters of studied synapses showed that significant changes consisting of (1) a reduction in size of presynaptic axon terminals, (2) a decrease in the number of synaptic vesicles, and (3) a diminution in the extent of the postsynaptic membrane thickening at the dendritic side developed as an effect of GABA-treatment. These results provide morphological evidence that long-term application of GABA to the SCG exerts a combination of effects on both presynaptic and postsynaptic elements. It is suggested that the structural changes observed in the fine structure of individual synapses within the SCG may play an integral role in the development of the synaptogenetic action of GABA.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 249 (1987), S. 325-329 
    ISSN: 1432-0878
    Keywords: Renin release ; Epithelioid cells ; Osmosensitivity of renin release ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Superfusion with hypoosmotic solutions stimulates renin release from rat epithelioid cells adherent to isolated glomeruli. This stimulatory effect may be related to the observed swelling of the secretory granules; the swelling may markedly increase the probability of pre-exocytotic fusions between the granule and cell membranes, and consequently increase the frequency of exocytotic events.
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