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  • 1
    Electronic Resource
    Electronic Resource
    Cytological studies on the spinning glands of the larva of Galleria mellonella: Respective rôles played by the nucleus, the Golgi apparatus, and the mitochondria during secretion (1930)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 49 (1930), S. 509-541 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spining in Galleria begins shortly after hatching and continues throughout larval life. The gland cells secrete continuously, irrespective of the act of spinning.The nucleus plays a direct and an importnat rôle in silk secretion by the migration of nucleoli into the cytoplasm, where they enlarge and synthesize a fatty material in the center; the fatty material is transformed into a non-soluble basophllic substance, which then changes into the secretory product in its final form. The processes of converting the fat into non-soluble substance and of converting the latter into the secretory product progress inwardly from the periphery of each secretory body. The secretory bodies or masses of secretory material break up into smaller and smaller masses and eventually into a fine dispersed state before their entrance into the lumen of the gland.The mitochondria are granular in the cells of the conductive portion and filamentous in those of the reservoir and secretory portions of the gland. In the secretory portion they are orientated with the long axis toward the gland lumen. Their rǒle in silk secretion is negligible or at most a minor one.The Golgi apparatus is in the form of discrete ring- and half-ring-shaped bodies and remains so during all stages of secretion. If it plays any rǒle in silk secretion, the fact has not been detected by the author.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050490208
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructure of the tongue and anterior process of the sublingual plica in four species of venomous snakes (1991)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 208 (1991), S. 279-292 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The general histology and ultrastructure of the tongue and anterior process of the sublingual plica of four Taiwanese venomous snakes, the Chinese cobra (Naja naja atra), banded krait (Bungarus multicinctus), Taiwan habu (Trimeresurus mucrosquamatus), and bamboo snake (Trimeresurus stejnegeri stejnegeri) are described.The tongue fork exhibits a mid-dorsal invagination that broadens gradually toward its base. No mid-ventral invagination is observed. The epithelial cells on both dorsal and ventral aspects of the tongue fork have large and small microfacets, micropores and microvilli. The cell size, distribution pattern of the large microfacets, and the number of small microfacets present on both sides of the fork are essentially the same within a species, but vary among species. The function of these ultrastructures on the cell surface might be for the capture of chemical substances. The large microfacets are raised areas of the cell membrane, each with a pale granule contained within. The chemical nature of the pale granule is not yet known. The small pores surrounding the large microfacets are shallow hollows left after the release of the pale granules from the microfacets. The basic histological pattern of the tongue fork of these species is similar, being composed of a mucosal layer outside and dense musculature inside. No taste buds are discernible.The anterior processes are concave-like expansions of the anteriormost portions of the sublingual plicae. The oblique folds and micropapillae of this organ might be helpful for receiving the chemicals collected on the tongue, when the tongue makes contact with the elevated processes. The elevated processes may penetrate the ducts of Jacobson's organs to effect the final transfer.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052080305
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructural features of a human genetic defect of cilia (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 7-12 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970020704
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  • 4
    Electronic Resource
    Electronic Resource
    Uncoupling of translocation across microsomal membranes from biosynthesis of influenza virus hemagglutinin (1988)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 36 (1988), S. 289-295 
    Details
    ISSN: 0730-2312
    Keywords: in vitro translation ; endoplasmic reticulum ; influenza hemagglutinin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: This communication presents our recent studies on the biosynthesis of influenza virus hemagglutinin (HA) in a mammalian-cell-free system and its translocation across microsomal membranes. RNAs coding for wild-type (full-length) and mutant (truncated) forms of HA were generated by in vitro transcription by using bacteriophage T7 DNA-dependent RNA polymerase. These RNAs were translated in a rabbit reticulocyte system that was supplemented with dog pancreas membranes, either before translation was initiated or after it had been artificially terminated with the antibiotic cycloheximide. All forms of HA could be cotranslationally translocated. However, only truncated molecules (83% of full length) could translocate after protein synthesis had been terminated. Posttranslational translocation was dependent on the presence of a functional N-terminal signal sequence and occurred only in the presence of ribosomes. The molecular mechanism of protein targeting and translocation across the membrane of the endoplasmic reticulum is discussed based on the signal hypothesis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240360309
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  • 5
    Electronic Resource
    Electronic Resource
    Extraplacental human fetal tissues express mRNA transcripts encoding the human chrorionic gonadotropin-β subunit protein (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 33 (1992), S. 1-6 
    Details
    ISSN: 1040-452X
    Keywords: Fetal gene expression ; hCG-β ; Polymerase chain reaction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The glycoprotein hormone human chorionic gonadotropin (hCG) is synthesized in large quantities by the developing placenta, reaching peak concentrations in maternal blood during the late first trimester and early midtrimester of pregnancey. In general it is believed that the β-subunit of this dimeric hormone is expressed in pituitary gonadotropes, thyrotropes, and trophoblasts, while the β-subunit is expressed exclusively by trophoblasts. Studies from our laboratory and other laboratories have shown that some midtrimester human fetal tissues, in addition to the placenta, can synthesize proteins that appear to be very similar to the β-subunit of hCG. To define precisely the nature of this putative hCG-β-subunit in extraplacental fetal tissues, we have examined the mRNA from a variety of human fetal and adult tissues using nucleic acid hybridization and reverse transcription-polymerase chain reaction (PCR) methods. Our results demonstrate that midtrimester fetal kidney and adrenal tissues contain hCG-β mRNA transcripts at concentrations comparable to that of placenta, while fetal lung, brain, muscle, and adult adrenal contain only trace to undetectable levels of hCG-β mRNA. By restriction endonuclease mapping of PCR fragments from fetal tissue cDNAs, we show that the hCG-β transcript expressed in midtrimester human fetal organs is a bone fide copy of hCG-β gene No. 5 of the β-subunit gene family located on chromosome 19. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080330102
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  • 6
    Electronic Resource
    Electronic Resource
    Proposed healing and consolidation mechanisms of rock salt revealed by ESEM (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 25 (1993), S. 456-464 
    Details
    ISSN: 1059-910X
    Keywords: Crushed rock salt ; ESEM ; Deformation ; Healing mechanism ; Consolidation mechanism ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The grain boundary healing behavior of crushed rock salt was mainly studied by employing the environmental scanning electron microscope (ESEM) to study the consolidation mechanism of rock salt backfill. Dedicated miniature round rock salt specimens were prepared for observation of the water trapping effect by using a cold stage in the ESEM to reach saturation conditions. Comparable high pressure pellets were prepared for measuring the crystal growth. Consolidation tests using materials made at different pressures and containing different moisture levels were conducted in order to construct the proposed mechanism. Direct observation of specimens in the ESEM resulted in viewing water trapped on the surface and the formation of a water meniscus between two particles. The concentration of brine at the grain boundary was observed as contributing to the amount of recrystallization. From aforementioned observations, a schematic drawing of the dissolution and recrystallization process may be redrawn. The amount of water therefore has a great effect on the consolidation of rock salt and is possibly due to the sliding, rotation, or crushing of the contact zone of the granular material. From such a study, tentative healing and consolidation mechanisms can be deduced. © 1993 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070250517
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  • 7
    Electronic Resource
    Electronic Resource
    Stimulation of the hexosemonophosphate-pentose pathway by pyrroline-5-carboxylate in cultured cells (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 110 (1982), S. 255-261 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Δ1-Pyrroline-5-carboxylic acid, an intermediate in the interconversions of proline, ornithine, and glutamate, is a potent stimulator of glucose oxidation through the hexosemonophosphate-pentose pathway. The effect is observed in cultured human fibroblasts, Chinese hamster ovary cells (CHO-K1), and rabbit kidney cells (LLC-RK1). In human fibroblasts, the magnitude of the stimulation of the hexosemonophosphate-pentose pathway is dependent on the concentration of added pyrroline-5-carboxylate and the effect is observed over a wide range of glucose concentrations. The mechanism of the effect is related to the generation of oxidizing potential in the form of NADP+ by pyrroline-5-carboxylate reductase concomitant with the conversion of pyrroline-5-carboxylate to proline. In LLC-RK1 cells, a cell line unique in having proline oxidase activity, proline also stimulated hexosemonophosphate-pentose pathway activity. Although pyrroline-5-carboxylate markedly stimulated the hexosemonophosphate-pentose pathway, it had no effect on glucose metabolism in the Embden-Meyerhof pathway or the tricarboxylic acid cycle. Since the hexosemonophosphate-pentose pathway is a source of ribose-5-phosphate, the precursor of phosphoribosyl pyrophosphate, the effect of pyrroline-5-carboxylate on the hexosemonophosphate-pentose pathway may link amino acid and nucleic acid metabolism.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041100306
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  • 8
    Electronic Resource
    Electronic Resource
    Induction of reverse transformation and normal cell cycle regulation by dibutyryl cAMP in a chemically transformed cell line (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 115 (1983), S. 255-259 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The objective of this study was to determine whether N6, O2-dibutyryl 3′,5′-adenosine monophosphate (db-cAMP)-induced reverse transformation in a chemically transformed mouse cell line, AKR-MCA, would restore normal cell cycle regulation, particularly with regard to their growth arrest in the early G1 period. The AKR-MCA cells were grown to confluency in the presence or absence of db-cAMP (0.5 mM) plus theophylline (1 mM). The confluent cultures were trypsinized and a portion of the cells were fused with mitotic HeLa cells to induce premature chromosome condensation, while the remaining cells were used to study the kinetics of initiation of DNA synthesis. The prematurely condensed chromosomes (PCC) of the control and the treated cultures were classified into G1, S, or G2 types on the basis of their morphology. The G1 PCC were further subclassified into six groups (+ 1- +6); +1 being the most condensed and +6 the most decondensed. The cyclic AMP (cAMP)-treated cells exnibited better attachment to the culture dish, were blocked in early G1 period at confluency, and entered S phase about 4 h later than the control following subculturing. In contrast, a majority of cells in the control cultures were arrested in S phase at confluency. These data indicate that the db-cAMP-induced reverse transformation in AKR-MCA cells at least partially restores normal cell cycle regulation in these chemically transformed cells.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041150307
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  • 9
    Electronic Resource
    Electronic Resource
    The role of the G1 period in the life cycle of eukaryotic cells (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 119 (1984), S. 77-81 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The objective of this study was to test the concept that the G1 period lacks any specific function in the life cycle of mammalian cells and hence could be drastically reduced without any effect on the generation time. HeLa cells were grown in medium containing an optimum dose (60 μM) of hydroxyurea at which the duration of S period was prolonged with little or no increase in generation time. At this concentration of hydroxyurea, we observed a maximum of 3 h (or 28.5%) reduction in the G1 period. We also studied the effects of synchronization in S phase by single and double thymidine blocks on cell size and its relationship to the duration of G1 in the subsequent cycle. By these treatments, we could reduce the G1 period by not more than 2 to 3 h. The reduction in G1 period was not directly proportional to the size (volume) of the G1 cells. These results suggest that G1 period has certain specific functions and cannot be eliminated by alterations in culture conditions.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041190113
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  • 10
    Electronic Resource
    Electronic Resource
    Microtubule inhibitors alter the secretion of β-glucuronidase by human blood platelets: Involvement of microtubules in release reaction II (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 96 (1978), S. 43-52 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of the antimicrotubular drugs colchicine and vinblastine on the blood platelet release reaction were studied by measuring release of 14C-5-hydroxytryptamine (14C-5-HT, release I) and β-glucuronidase (release II) from gel-filtered human platelets. β-glucuronidase release induced by thrombin was significantly inhibited by colchicine (0.01-1 mM) or vinblastine (0.05-0.1 mM). Release of 14C-5-HT, however, was unaffected at low concentrations of colchicine and only slightly inhibited at higher concentrations. Inhibition of β-glucuronidase release depended on colchicine or vinblastine concentrations and decreased with longer time intervals (1′, 5′, 20′) after thrombin stimulation. Levels of the cytoplasmic enzyme, lactic acid dehydrogenase, in supernatants of colchicine treated platelets were not significantly different from controls. Colchicine also inhibited β-glucuronidse release, but not 14C-5-HT release, induced by trypsin and sodium arachidonate. Binding of 14C-colchicine by platelets was measured and it was found that platelet aggregation and release of 5-HT induced by adenosine diphosphate, epinephrine and collagen proceeded without any alteration in colchicine binding. However, significant increases in the rate and degree of colchicine binding were observed when platelets were stimulated by thrombin, trypsin and arachidonic acid which induced aggregation, release of both 5-HT and β-glucuronidase. The results suggest that an alteration in platelet microtubules is correlated with the physiologic response resulting in release II and that the cellular mechanisms effecting release I and II by platelets differ qualitatively in that the microtubules may facilitate release II.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1040960106
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