Results 131 to 140 of about 7,530 (183)

Acrosomal chromocentre in newt spermiogenesis

Nature, 1975
STUDY of the distribution of satellite DNA during the later stages of spermiogenesis led to a model in which chromosomes of the mature sperm nucleus are U-shaped with posterior centromeres1,2. We have now studied a closely related chromosome marker—constitutive heterochromatin—and, using C banding techniques3, have found a polarised arrangement of ...
M, Schmid, W, Krone
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Spermiogenesis ofLacerta vivipara

Journal of Ultrastructure Research, 1985
Abstract To the common aspects of spermiogenesis in Reptilia, several new organelles are described in the lizard. One or two nuclear pouches, formed by the invagination of the nuclear envelope, contain a substance similar to that of the perinuclear substance.
J.L. Courtens, A. Depeiges
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Spermiogenesis in hibernating golden hamsters

Experientia, 1967
Wahrend einer Periode von Dezember bis Marz wurden von Goldhamstern im Winterschlaf und gleichzeitig von Kontrolltieren, die bei Zimmertemperatur gehalten wurden, die linken Testes untersucht. Aus der Korrelation zwischen dem histologischen Bild und dem relativen Organgewicht ging hervor, dass der Winterschlaf keinen Einfluss auf die Proliferation der ...
J H, Smit-Vis, M A, Akkerman-Bellaart
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Membranous tubes in pseudoscorpion spermiogenesis

Tissue and Cell, 1989
The highly complicated differentiation of the spermatid in the pseudoscorpion Diplotemnus sp. is accomplished without the presence of microtubules. Instead membranous tubes measuring approximately 50 nm in diameter and closely associated with endoplasmic reticulum are found from early to mid spermatids. The lumen of the tube is devoid of electron dense
G, Werner, S R, Bawa
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Selenium in mammalian spermiogenesis

bchm, 2007
Abstract The role of selenium in male fertility is reviewed with special emphasis on selenoprotein P and phospholipid hydroperoxide glutathione peroxidase (GPx4) in spermiogenesis. Inverse genetics reveal that selenoprotein P is required for selenium supply to the testis. GPx4 is abundantly synthesized in spermatids.
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Nuclear basic proteins in spermiogenesis

Biochimie, 1998
In animal species, spermiogenesis, the late stage of spermatogenesis, is characterized by a dramatic remodelling of chromatin which involves morphological changes and various modifications in the nature of the nuclear basic proteins. According to the evolution of species, three situations can be observed: a) persistence of somatic histones or ...
D, Wouters-Tyrou, A, Martinage, P, Chevaillier, P, Sautière   +3 more
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Microtubules and Spermiogenesis

1983
Numerous works on spermiogenesis did not focus on the occurence of microtubules. They have been conducted before the first use of glutaraldehyde as fixative agent or in very archaic phylla such as spongia (54) or in species with so scarce microtubules that they remain hidden to the observer sagacity.
J. L. Courtens, B. Delaleu, M. Loir
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Acrosome Formation in Bandicoot Spermiogenesis

Nature, 1956
THERE has been some disagreement about the presence of an acrosome in marsupial spermatozoa. Students of spermiogenesis1 are generally agreed that none is present, whereas Retzius2 found a diminutive body at the proximal end of the mature sperm head in some species, although not in Didelphys 3.
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The cell surface during mammalian spermiogenesis

Developmental Biology, 1978
Abstract In this paper the origin of the membrane investing the newly formed elongating organelles during mammalian spermiogenesis is studied. According to previous authors, the beginning axoneme is hollowed in a deep membrane invagination. We demonstrate that in man, rat, and bull this new surface is formed by several clusters of Golgi-originated ...
B, Baccetti, E, Bigliardi, A G, Burrini
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Ultrastructural features of human spermiogenesis

Zeitschrift f�r Zellforschung und Mikroskopische Anatomie, 1969
The ultrastructural features of human spermiogenesis have been correlated with the light microscopic appearance of spermatids. The development of the acrosome together with the changes in nuclear shape, position, size and chromatin configuration are the most useful criteria for ultrastructural staging of spermiogenesis.
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