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  • 1
    Electronic Resource
    Electronic Resource
    Nuclear magnetic resonance study of muscle water protons in muscular dystrophy of chickens (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 107 (1981), S. 139-145 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using the pulsed nuclear magnetic resonance (NMR) spectroscopy, the spin-lattice (T1) and the spin-spin (T2) relaxations times of water protons from samples of pectoralis major muscles of normal (line 412) and homozygous dystrophic (line 413) chickens were measured. Both the T1 and T2 were significantly increased (P 〈 0.05) in the dystrophic muscles. The mean values of the relaxation times are given ± S.D. The T1 values were 654 ± 22 msec in normal and 692 ± 41 msec in dystrophic muscles. The T2 values for normal and dystrophic muscles were 39 ± 4 msec and 52 ± 7 msec, respectively. Although the water content of dystrophic muscles (78.9 ± 0.6%) determined by gravimetric methods was significantly higher than normal muscles (74.9 ± 1.1%), this difference in tissue hydration could not explain quantitatively the increase of T1 and T2 values in the dystrophic muscles. The results of the measurements of the relaxation times seem to suggest that there are changes in the composition and/or conformational state of the proteins.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041070115
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  • 2
    Electronic Resource
    Electronic Resource
    Insulin inhibition of protein degradation in cell monolayers (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 105 (1980), S. 335-346 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Protein degradation has been measured in confluent monolayers of eleven lines of contact-inhibited cells and ten transformed lines as the rate of release of trichloroacetic acid-soluble radioactivity after prelabeling cell protein with [3H]leucine. Insulin, at concentrations from 10-12 M to 10-6 M, has been added at the beginning of the 4-hour degradation period to detect selective effects of this hormone as an inhibitor of the inducible proteolysis occurring in serumfree medium. In addition insulin binding measurements have been performed on selected cell lines in an attempt to relate receptor properties to insulin action. Substantial effects of insulin are found in most cells with a selective inhibition at low insulin concentrations noted in several of the transformed lines. The difference in insulin sensitivity is not entirely definitive because temperature-sensitive transformation mutants of NRK cells are not more sensitive to insulin at a temperature where they show the transformed phenotype. Although insulin receptors on different cell lines have similar binding properties, two of the hepatomas used, H35 and MH1C1, show inhibition of protein degradation at insulin concentrations where receptor occupancy is extremely low. Calvarial osteoblast-like cells have a high rate of protein degradation which can be reduced by growth factors but not by insulin. The lack of an insulin response is a consequence of poor insulin binding to the cells. Insulin binds to the osteogenic sarcoma cells in substantial amounts. However, its normal action to inhibit the induced proteolysis is restricted because with these cells no increase of proteolysis occurs in serum-free medium. Generally higher rates of protein degradation are observed in the contact-inhibited lines than the transformed cells. We suggest that this difference may provide a selective growth advantage to transformed cells.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041050216
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  • 3
    Electronic Resource
    Electronic Resource
    Intracellular concentration of elements in normal and dystrophic skeletal muscles of the chicken (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 103 (1980), S. 193-200 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this study, the intracellular concentrations of six elements (mmole/kg dry weight) were directly measured in the muscle fibers of pectoralis major muscles of eight week old, genetically dystrophic and normal chickens by the X-ray microanalysis technique. The extent of muscle degeneration was evaluated by morphometric measurements of muscle fiber diameter and other histological changes. A significant increase in the concentration of intracellular sodium and chlorine was evident in dystrophic muscles. The concentration of intracellular sodium was 127.0 ± 35.0 in the muscle fibers of dystrophic chicks compared to 65.7 ± 16.5 in normal controls. The concentration of chlorine was 90.5 ± 27.5 and 54.1 ± 5.5 in the muscle fibers of dystrophic and normal chicks respectively. The intracellular concentrations of potassium, magnesium, phosphorous, and sulfur remained unchanged in the dystrophic condition. Morphometric studies revealed that the dystrophic pectoralis muscles contain fewer but thicker fibers per unit area compared to normal pectoralis muscles. The importance of these findings are discussed in relation to the results of earlier investigations.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041030204
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  • 4
    Electronic Resource
    Electronic Resource
    Physarum myosin light chain binds calcium (1980)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 1 (1980), S. 63-71 
    Details
    ISSN: 0886-1544
    Keywords: Physarum polycephalum ; myosin light chains ; polyacrylamide gel electrophoresis ; calcium ; cytoplasmic streaming ; actomyosin ATPase regulation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Myosin from the slime mold Physarum polycephalum contains three sizes of polypeptides: a heavy chain and two light chains, LC-1 and LC-2. Using a simple qualitative test for calcium binding by comparing electrophoretic migration of the polypeptides in sodium dodecy1 sulfate (SDS) acrylamide gels in the presence and absence of calcium, we have found that Physarum myosin light chain LC-2 migrates with an apparent molecular weight of 16,900 daltons in the presence of the metal ion chelator ethylene glycol bis (B-aminoethyl ether) N,N′-tetraacetic acid (EGTA). However, if calcium chloride is added to the sample prior to electrophoresis, the apparent molecular weight decreases to 16,100. Lanthanide and cadmium ions, but not magnesium, can substitute for calcium. Because the ionic radii of Ca2+, La3+, and Cd2+ are almost identical, we conclude that Physarum myosin LC-2 possesses a very size-specific binding site for calcium. Physarum myosin LC-1 and the heavy chain give no evidence for binding calcium by this test. Since cytoplasmic streaming in the plasmodium of Physarum requires calcium, our evidence indicates that the calcium-binding property of Physarum myosin LC-2 may be important in regulating the production of force by actomyosin in the ectoplasm. Unexpectedly, the myosin light chain in Physarum capable of binding calcium, LC-2, is the essential light chain, while LC-1 is a member of the regulatory class of myosin light chains [V. T. Nachmias, personal communication]. Until now, essential myosin light chains have not been shown to have high affinity divalent cation binding sites. This means a new version of the myosin-based model for actomyosin regulation by calcium may be required to explain cytoplasmic movement in Physarum, and perhaps in other motile systems involving cytoplasmic myosins as well.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970010106
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  • 5
    Electronic Resource
    Electronic Resource
    Quantitative analysis of axonemal bends and twists in the quiescent state of ciona sperm flagella (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 247-259 
    Details
    ISSN: 0886-1544
    Keywords: spermatozoa ; Ciona ; axoneme ; quiescence ; twist ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A simple planar model of sliding can predict the amount of sliding required to form a certain degree of bend. The accuracy of this prediction relies on the assumptions that no twists occur in the axoneme and that no sliding occurs at the base. However, previous studies indicated that twists may occur.This paper explores a new method for quantitating and analyzing twists. Preliminary results using this method showed that there were twists. In order to control for possible artifacts due to fixation and other preparative procedures, the characteristic S-shaped quiescent state of Ciona spermatozoa was studied.Analyses of platinum replicas of those flagella in which this waveform is well preserved suggest that most, if not all, of the twists observed are due to the artifact of a curved shape settling onto a surface. Detailed analyses indicate that if twists do occur in quiescent sperm, they are probably less than 0.4 radian. Since axonemes are evidently easily twisted in rigor, and even after fixation, caution should be exercised in interpretation of axonemal twists.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970030305
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  • 6
    Electronic Resource
    Electronic Resource
    Hormonal regulation of zona-binding ability and fertilizing ability of rat epididymal spermatozoa (1984)
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 21-30 
    Details
    ISSN: 0148-7280
    Keywords: rat ; zona-binding ; fertility ; epididymis ; spermatozoa ; testosterone ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rat spermatozoa from the proximal caput, the proximal corpus, the middle corpus, and the distal cauda epididymidis were examined for their ability to bind to the zona pellucida after a 1-, 2.5-, or 4.5-h incubation at 34°C with rat eggs in cumulus. Caput spermatozoa did not bind to the zona after 1, 2.5, or 4.5 h of incubation. Corpus spermatozoa did bind to the zona, but the percentage of eggs with bound spermatozoa and number of bound spermatozoa per egg increased with the length of incubation. Cauda spermatozoa bound readily to the zona pellucida, and their zona binding ability did not change with longer incubations. It thus appears that rat spermatozoa gradually acquire the ability to bind to the zona pellucida in the corpus epididymidis.The zona-binding capacity of cold immobilized cauda spermatozoa, defined as the percentage of eggs with bound spermatozoa, increased with the number of spermatozoa incubated and reached a plateau characteristic of the endocrine status of the animal. After castration, zona-binding ability is progressively lost from day 3 until day 10 where it is nil. Testosterone supplementation maintains zona-binding ability to control levels. Similarly, fertilizing ability declines from day 5 after castration until day 10. Testosterone prevents this loss of fertilizing ability. It thus appears that the development of zona-binding ability during epididymal transit is, like the development of fertilizing ability, under androgen regulation.The close correlation between the onset of fertilizing ability and zona-binding ability during maturation, the loss of fertilizing ability and zona-binding ability after castration, and the recovery of both fertilizing ability and zona-binding ability with testosterone treatment suggests that the androgen-dependent development of zona-binding ability is an important component of the acquisition of sperm fertilizing ability during epididymal transit.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120090103
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  • 7
    Electronic Resource
    Electronic Resource
    Changes at the hamster oocyte surface from the germinal vesicle stage to ovulation (1984)
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 387-397 
    Details
    ISSN: 0148-7280
    Keywords: oocyte ; meiosis ; sperm-oocyte interaction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Immature and ovulated hamster oocytes were studied with the scanning electron microscope. Immature oocytes at the germinal vesicle stage have their surface uniformly covered by microvilli. When meiosis has progressed to the first meiotic metaphase the overlying surface shows the differentiation of a circular area 19 μm in diameter with a low density of microvilli. Later, from this region the first polar body emerges, and the oocyte surface at the point from which it was extruded shows a cluster of cytoplasmic, conical projections. When the zona-free oocytes are cultured at 37°C for 5 minutes these projections disappear and the oocyte surface at that point becomes smooth. However, when the oocytes remain in the oviduct for several hours after ovulation these projections remain unchanged. The in vitro interactions of capacitated hamster sperm with the immature oocyte was always seen at microvillus surfaces and never associated with the differentiated regions.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120090404
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  • 8
    Electronic Resource
    Electronic Resource
    Analytical subcellular distribution of cAMP-dependent protein kinase activity in bull sperm (1984)
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 433-444 
    Details
    ISSN: 0148-7280
    Keywords: bull sperm ; cell fractionation ; differential centrifugation ; centrifugal elutriation ; cAMP-dependent protein kinase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The distribution of the cAMP-dependent protein kinase activity in bull ejaculated sperm has been investigated. This activity proved to be mainly present in a soluble form inside the cell. Sperm fractionation into heads and flagellar fragments, using differential centrifugation or centrifugal elutriation, has shown that the particulate cAMP-dependent protein kinase activity was mainly associated with the flagellar structures. A much activity was shown to be associated with the head fraction. Some activity could also be detected in the purified plasma membrane fraction.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120100409
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  • 9
    Electronic Resource
    Electronic Resource
    Spermatozoa of chromosomally heterozygous mice and their fate in male and female genital tracts (1984)
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 273-286 
    Details
    ISSN: 0148-7280
    Keywords: mouse spermatozoa ; Robertsonian chromosomes ; DNA content ; sperm aneuploidy ; genital tracts ; prezygotic selection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The fate of morphologically normal but chromosomally abnormal spermatozoa derived from mice with variable degrees and complexity of Robertsonian heterozygosity was studied at different sites along the male and female genital tract by Feulgen-DNA measurements. In addition, the percentage frequencies of morphologically abnormal spermatozoa in transit along the male and female genital tracts were studied.It was found that during transit from the epididymis to the vas deferens the distribution of the Feulgen-DNA contents of morphologically normal spermatozoa changed: Spermatozoa with chromatin with the extremely low or high Feulgen staining intensity disappeared. The percentages of morphologically abnormal sperm cells did not change at these levels. In the female genital tracts, the distribution of Feulgen-DNA content of morphologically normal spermatozoa did not show significant changes. This indicates that spermatozoa are able to reach the fallopian tube in spite of gross genome unbalance. There is evidence that unbalanced spermatozoa take part in the fertilization process, producing abnormal zygotes subject to postzygotic loss. Conversely morphologically abnormal spermatozoa were preferentially lost before they reached the fallopian tube, suggesting they had been eliminated prezygotically.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120090305
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  • 10
    Electronic Resource
    Electronic Resource
    Quantitative studies on the skin of the paired species of lampreys, Lampetra fluviatilis (L.) and Lampetra planeri (BLOCH) (1980)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 164 (1980), S. 39-46 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The number of mucous, club, and granular cells in the epidermis, and the number of rows of subcutaneous adipose cells, as well as the thickness of the epidermis and the dermal collagen layer, have been recorded for the larval and metamorphosing stages of the anadromous parasitic lamprey, Lampetra fluviatilis, and for the larval, metamorphosing, and adult stages of the nonparasitic lamprey, Lampetra planeri.In L. fluviatilis, the mucous cells predominated in all stages but were more abundant in fully metamorphosed individuals than in larvae. During metamorphosis, the number of granular cells increased continuously, whereas the club cells showed little change. Although lampreys do not feed during metamorphosis, there was an increase in the thickness of the epidermis and in the dermal collagen sheath; the latter increase probably foreshadows the increase in activity by the adults. Simultaneously, there is a reduction in the subcutaneous fat layer, which can be attributed to mobilization of lipid as an energy source.Changes similar to those just described for L. fluviatilis were also found in metamorphosing L. planeri. However, the pattern altered markedly during adult stages in this nonparasitic species. There were marked declines in the number of cells, in the thickness of the epidermis, in the width of the collagen sheath, and in the quantity of subcutaneous fat.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051640104
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