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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 184 (1985), S. 1-22 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Males of Euphydryas editha (Lepidoptera: Nymphalidae) need their antennae to mate successfully, but females do not. Antennal structure was investigated in the hope of explaining this functional dimorphism, which is opposite to that in other butterflies (e.g., Myers, '68; Grula and Taylor, '80). No external differences between the sexes were observed with electron microscopy. There are four types of antennal sensilla: the spine, which acts mainly as a mechanoreceptor, shallow dish hairs and hidden hairs, which are chemoreceptors, and a whiplike sensillum of uncertain function. The internal morphology of male and female antennae differs in several respects which may relate to functional differences. The mating systems of butterflies are discussed briefly to explain our results and those of others.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 199 (1989), S. 1-13 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study examines the morphology of sporadic congenital microphthalmia in 1-day-old chicks, with particular emphasis on the neural retina. On the basis of the size of the eyeball it is possible to classify microphthalmia into two groups, severe and mild. In severe microphthalmia (less than 5 mm in equatorial diameter), the eyeball is severely malformed, but in most cases it shows evidence of an organized neural retina. Although ganglion cells and an optic nerve head are present in a small proportion of these retinae, we could not trace an optic nerve projection to the brain. These results indicate that some ganglion cells are able to be sustained after the period of naturally occurring cell death, suggesting either that those ganglion cells have established some contact with the central nervous system or that the presence of their axons in a rudimentary optic nerve is adequate for survival. In mild microphthalmia (greater than 5 mm in equatorial diameter), the most consistent abnormality is a defect in the pecten, which together with other abnormalities such as orbital cysts and colobomas indicates that the major abnormality occurs in the region of the choroid fissure. Associated with these defects are abnormalities within the ganglion cell layer. In some cases the number of ganglion cells was reduced, and in others the numbers of both ganglion and displaced amacrine cells were reduced. Unexpectedly, there were localized regions completely devoid of cells in the ganglion cell layer. The timing of the congenital defect may provide some clue as to the presence of a critical period in which displaced amacrine cells are formed or are sensitive to events related to ganglion cell loss.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 128 (1986), S. 223-230 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When 1mM ATP is added to human dermal fibroblasts (DF) in monolayer culture permeabilized by glycerol, they undergo a rapid reduction in length and their intracellular actin filaments aggregate. This process is referred to as cell contraction. Treating glycerol-permeabilized DF with alkaline phosphatase before adding 1mM ATP should cause dephosphorylation. Dephosphorylated preparations do not undergo cell contraction initiated by ATP. When myosin light-chain kinase (MLCK) isolated from turkey gizzard is added with cofactors to cells dephosphorylated by alkaline phosphatase treatment, contraction is restored. DF incubated for 24 h with db cAMP or cholera toxin show elevated intracellular concentrations of cAMP and little cell contraction. Contraction is reestablished when MLCK with cofactors is incubated with these preparations before ATP is added. Fibroblasts from Epidermolysis Bullosa dystrophica recessive patients produce excess cAMP. Those cells show minimal contraction, however; treating them with MLCK and cofactors renews contraction brought about by ATP. When DF are incubated with trifluoperazine to block calmodulin-dependent enzyme reactions, cell contraction is inhibited. Adding cytochalasin B disrupts microfilaments and also inhibits contraction. This work supports the idea that myosin ATPase is critical to cell contraction. Myosin ATPase is dependent on the phosphorylation of the regulatory peptide, myosin light chain. Elevating intracellular concentrations of cAMP or treatment of permeabilized cell preparations with alkaline phosphatase may inhibit myosin ATPase activity. The restoration of phosphorylation by adding MLCK with cofactors served to reestablish cell contraction.
    Additional Material: 4 Ill.
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  • 4
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1987-06-12
    Description: The effect of electric current on protein biosynthesis in mammalian fibroblasts was investigated with neonatal bovine fibroblast-populated collagen matrices. The field strength dependence of electric field modulation of proline incorporation into extracellular and intracellular protein was measured over a frequency range from 0.1 to 1000 hertz. A frequency- and amplitude-dependent reduction in the rate of incorporation was observed. In tissues containing cells aligned either parallel or perpendicular to the electric field, this response was dependent on the orientation of the cells relative to the direction of the applied electric field. This study demonstrates that currents of physiological strength can stimulate alterations in biosynthesis and thereby may influence tissue growth, remodeling, and repair.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McLeod, K J -- Lee, R C -- Ehrlich, H P -- New York, N.Y. -- Science. 1987 Jun 12;236(4807):1465-9.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3589667" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Aplysia/physiology ; Cattle ; Electricity ; Fibroblasts/*metabolism/physiology ; Microscopy, Electron, Scanning ; *Protein Biosynthesis
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 5
    Publication Date: 1988-06-24
    Description: Platelet-activating factor (PAF) is a naturally occurring phospholipid that serves as a critical mediator in diverse biological and pathophysiological processes. In this study of the interactions of PAF with neuronal cells, it was found that PAF increased the intracellular levels of free calcium ions in cells of the clones NG108-15 and PC12. The increase was dependent on extracellular calcium and was inhibited by the antagonistic PAF analog CV-3988 and by the calcium-influx blockers prenylamine and diltiazem. A functional consequence of this interaction was revealed by measuring a PAF-elicited, Ca2+-dependent secretion of adenosine triphosphate from PC12 cells. Exposure of NG108-15 cells for 3 to 4 days to low concentrations of PAF induced neuronal differentiation; higher concentrations were neurotoxic. Thus, by influencing Ca2+ fluxes, PAF may play a physiological role in neuronal development and a pathophysiological role in the degeneration that occurs when neurons are exposed to circulatory factors as a result of trauma, stroke, or spinal cord injury.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Kornecki, E -- Ehrlich, Y H -- HL 32594/HL/NHLBI NIH HHS/ -- New York, N.Y. -- Science. 1988 Jun 24;240(4860):1792-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Psychiatry, University of Vermont College of Medicine, Burlington 05405.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3381103" target="_blank"〉PubMed〈/a〉
    Keywords: Adrenergic Fibers/cytology ; Animals ; Benzodiazepines/pharmacology ; Calcium/*physiology ; Calcium Channel Blockers/pharmacology ; Cell Line ; Cell Survival/drug effects ; Cholinergic Fibers/cytology ; Neurons/cytology/*physiology ; *Neurotoxins ; Phospholipid Ethers/pharmacology ; Platelet Activating Factor/*pharmacology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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