Results 301 to 310 of about 489,854 (362)
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Sperm size and sperm competition in birds
Proceedings of the Royal Society of London. Series B: Biological Sciences, 1992In a sample of 20 species of North American passerine birds we found no relation between sperm size and mating system like that previously reported in mammals (Gomendio & Roldan (Proc. R. Soc. Lond. B 243, 181 (1991)). Instead, we found a positive correlation between sperm length and the length of female sperm storage tubules (SSTS) and a negative ...
J V, Briskie, R, Montgomerie
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Sperm‐sperm associations in the loris epididymis
Gamete Research, 1987AbstractIn a few mammals, the passage of maturing spermatozoa through the epididymis is characterized by development of persistent associations between one or more neighboring cells over the acrosomal region. The converse situation is described here in the loris, Nycticebus coucang, a prosimian primate.
D M, Phillips, J M, Bedford
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Sperm centriole disfunction and sperm immotility
Molecular and Cellular Endocrinology, 2000The two main causes of complete or nearly complete asthenozoospermia are necrozoospermia (presence of only non-viable spermatozoa) and the different ultrastructural abnormalities of spermatozoa. Ultrastructural alterations may affect also the function of the sperm centrosome, which can result in impaired motility.
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American Journal of Reproductive Immunology, 1992
ABSTRACT: Antisperm antibodies (ASA) occur in 1% to 30% of infertile couples. Mechanisms by which ASA impair fertility include prevention of fertilization by decreasing acrosome reaction and/or zona pellucida binding, and postfertilization effects. Treatment for ASA involves assisted reproductive technologies.
A J, Peters, C B, Coulam
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ABSTRACT: Antisperm antibodies (ASA) occur in 1% to 30% of infertile couples. Mechanisms by which ASA impair fertility include prevention of fertilization by decreasing acrosome reaction and/or zona pellucida binding, and postfertilization effects. Treatment for ASA involves assisted reproductive technologies.
A J, Peters, C B, Coulam
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Sperm quality in fish: Determinants and affecting factors.
Theriogenology, 2019Fish sperm quality assessment is helpful for optimizing production and for monitoring the environmental state. Sperm can be monitored relatively easy and, to date, various analyses have been applied and proven to be helpful in this task.
R. Kowalski, B. Cejko
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Reviews of Reproduction, 1999
Communication between spermatozoa and egg before contact by chemotaxis appears to be prevalent throughout the animal kingdom. In non-mammalian species, sperm chemotaxis to factors secreted from the egg is well documented. In mammals, sperm chemotaxis to follicular factors in vitro has been established in humans and mice.
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Communication between spermatozoa and egg before contact by chemotaxis appears to be prevalent throughout the animal kingdom. In non-mammalian species, sperm chemotaxis to factors secreted from the egg is well documented. In mammals, sperm chemotaxis to follicular factors in vitro has been established in humans and mice.
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Sperm Capacitation and Acrosome Reaction in Mammalian Sperm.
Advances in Anatomy, Embryology and Cell Biology, 2016Physiological changes that endow mammalian sperm with fertilizing capacity are known as sperm capacitation. As part of capacitation, sperm develop an asymmetrical flagellar beating known as hyperactivation and acquire the ability to undergo the acrosome reaction. Together, these processes promote fertilizing competence in sperm. At the molecular level,
Cintia Stival +5 more
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Archives of Andrology, 2000
Available data on dry and hydrated nuclear volume of mammalian spermatozoa indicate that available volume is clearly insufficient to contain sperm chromatin packed in nucleosome-like structures. Therefore, sperm DNA-protein complexes must be packed differently than somatic DNA-protein complexes.
G, Fuentes-Mascorro +2 more
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Available data on dry and hydrated nuclear volume of mammalian spermatozoa indicate that available volume is clearly insufficient to contain sperm chromatin packed in nucleosome-like structures. Therefore, sperm DNA-protein complexes must be packed differently than somatic DNA-protein complexes.
G, Fuentes-Mascorro +2 more
openaire +2 more sources