نتایج جستجو برای: sperm biology

تعداد نتایج: 198940  

Journal: :Turkish journal of urology 2017
Fuat Kızılay Barış Altay

Conventional semen analysis solely is not completely adequate to predict pregnancy outcomes. Therefore, advanced sperm function tests have been developed and introduced to clinical practice. These tests use different methods and techniques to evaluate different stages of fertilization steps. In this review, we reported some commonly used sperm function tests: sperm penetration assay, sperm-zona...

2012
Gulab Chandra A. Aggarwal A. Singh A. K. Singh M. Kumar R. Kushwaha Y. K. Singh

Dairy Cattle Physiology Division, National Dairy Research Institute, Karnal 132 001, India Received: 30-07-2011 Accepted: 18-08-2011 ABSTRACT Oxidative stress occurs when the production of potentially destructive reactive oxygen species (ROS) exceeds the bodies own natural antioxidant defenses, resulting in cellular damage. ROS, defined as including oxygen ions, free radicals and peroxides, are...

Journal: :Current Biology 2006
Andrew Singson

Studies of the reproductive biology of the nematode Caenorhabditis elegans are providing valuable insights into the evolution and diversity of reproductive strategies [1,2]. The successful production of progeny in any species also highlights many fundamental problems in cell biology. Research on the amoeboid sperm of nematodes addresses a number of issues of broad biological significance, inclu...

Journal: :Current Biology 2004
Matthew J.G. Gage Christopher P. Macfarlane Sarah Yeates Richard G. Ward Jeremy B. Searle Geoffrey A. Parker

Sperm competition occurs when sperm from more than one male compete for fertilizations. This form of post-copulatory sexual selection is recognized as a significant and widespread force in the evolution of male reproductive biology and as a key determinant of differential male reproductive success. Despite its importance, however, detailed mechanisms of sperm competition at the gamete level rem...

2012
Mohammad Ali Ghaffari Morad Rostami

BACKGROUND Nitric oxide (NO) is synthesized from L-arginine by a family of enzymes known as nitric oxide synthases. Low concentrations of NO is essential in biology and physiology of spermatozoa, but high amounts of NO is toxic and has negative effects on sperm functions. Moreover, sperm membrane contains high concentrations of polyunsaturated fatty acids that are highly susceptible to oxidativ...

2017
Rodolfo A. Rey

tau.amegroups.com © Translational Andrology and Urology. All rights reserved. The study of physiology of reproduction, particularly in mammalian species, experienced glorious times in the second half of the twentieth century. However, with the advent of intracytoplasmic sperm injection (ICSI), the decade of 1990 appeared to forecast the demise of translational research in male reproductive biol...

2008
D. W. Erikson A. L. Way R. P. Bertolla D. A. Chapman G. J. Killian

Sperm must undergo a process termed capacitation in the female reproductive tract before they are capable of fertilization. Previous studies strongly suggest that capacitation of sperm occurs in the oviduct. The secreted extracellular matrix phosphoprotein osteopontin (OPN) has been positively correlated to fertility in Holstein bull seminal plasma and identified in the bovine oviduct, where we...

2013
José O. Carvalho Luciano P. Silva Roberto Sartori Margot A. N. Dode

Sperm dimensions and the question of whether X and Y chromosome-bearing sperm differ in size or shape has been of great interest, especially for the development of alternative methods to sort or classify sperm cells. The aim of the present study was to evaluate possible differences in the shape and size of the sperm head between X and Y chromosome-bearing sperm by atomic force microscopy (AFM)....

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