Results 251 to 260 of about 316,099 (294)
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SPERM COMPETITION AND THE EVOLUTION OF NONFERTILIZING SPERM IN MAMMALS
Evolution, 1991Nonfertilizing sperm with special morphologies have long been known to exist in invertebrates. Until recently, abnormal sperm in mammals were considered errors in production. Now, however, Baker and Bellis (1988, 1989) have proposed that mammalian sperm, like some invertebrate sperm, are polymorphic and adapted to a variety of nonfertilizing roles in ...
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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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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
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Trends in Cognitive Sciences, 2002
Evidence is accumulating that in many species, males deliver more sperm to some females and fewer to others depending on how valuable they perceive the copulation. Do humans have any control over the number of sperm they ejaculate?
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Evidence is accumulating that in many species, males deliver more sperm to some females and fewer to others depending on how valuable they perceive the copulation. Do humans have any control over the number of sperm they ejaculate?
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Sperm competition games: sperm selection by females
Journal of Theoretical Biology, 2003We analyse a co-evolutionary sexual conflict game, in which males compete for fertilizations (sperm competition) and females operate sperm selection against unfavourable ejaculates (cryptic female choice). For simplicity, each female mates with two males per reproductive event, and the competing ejaculates are of two types, favourable (having high ...
M A, Ball, G A, Parker
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Sperm or No Sperm, that is the question. Or is it?
2023Comte, Jennifer +7 more
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Sperm Capacitation and Acrosome Reaction in Mammalian Sperm
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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Donor sperm for intracytoplasmic sperm injection
The Lancet, 2001G, Tews, C, Yaman, T, Ebner, M, Moser
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1998
Abstract The new reproductive technologies force us to think about embryos and gametes in ways never before necessary or possible. In particular, cryopreservation enables sperm and fertilized eggs to be maintained for long periods outside the body, giving rise to questions about to whom they belong and what may be done with them.
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Abstract The new reproductive technologies force us to think about embryos and gametes in ways never before necessary or possible. In particular, cryopreservation enables sperm and fertilized eggs to be maintained for long periods outside the body, giving rise to questions about to whom they belong and what may be done with them.
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[Sperm antigens and sperm antibodies].
Zentralblatt fur Gynakologie, 1986A review is given about the actual knowledge of sperm antigens and antibodies. For the detection of sperm antibodies a great number of tests exists with different value for the clinical work. The penetration tests are suitable for screening investigations.
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