نتایج جستجو برای: acrosome
تعداد نتایج: 2293 فیلتر نتایج به سال:
Evaluation of the acrosome reaction can shed light on the fertilising competence of spermatozoa. To eliminate false-positive results when evaluating the acrosome status of human sperm cells, two viability probes propidium iodide (PI) and 7-amino-actinomycin D (7-AAD) were compared for their ability to stain nonviable cells post-fixation and permeabilisation. Both the mean fluorescence and % dea...
BACKGROUND The aim of this study was to investigate the in vitro effects of the Fusarium fungus-derived mycotoxin, zearalenone and its derivatives alpha-zearalenol and beta-zearalenol on motility parameters and the acrosome reaction of stallion sperm. Since the toxic effects of zearalenone and its derivatives are thought to result from their structural similarity to 17beta-estradiol, 17beta-est...
The ultrastructure of spermatozoa in three species of cambarid crayfish, Cambarus robustus, Orconectes propinquus, and Orconectes rusticus, were studied and compared with eight previously studied species from different crayfish families using morphological features and biometrical data. The ultrastructure of spermatozoa show a generally conserved pattern including an acrosome and nucleus in the...
Sperm-head elongation and acrosome formation, which take place during the last stages of spermatogenesis, are essential to produce competent spermatozoa that are able to cross the oocyte zona pellucida and to achieve fertilization. During acrosome biogenesis, acrosome attachment and spreading over the nucleus are still poorly understood and to date no proteins have been described to link the ac...
Two processes, namely capacitation and acrosome reaction, are of fundamental importance in the fertilization of oocyte by spermatozoon. Physiologically occurring in the female genital tract, capacitation is a complex process, which renders the sperm cell capable for specific interaction with the oocyte. During capacitation, modification of membrane characteristics, enzyme activity and motility ...
Small pieces of the sperm sacs of Lumbricus herculeus were fixed for 4 hours in chrome-osmium, embedded in methacrylate, sectioned with a Porter-Blum microtome, and studied with a R.C.A. EMU-2C electron microscope. Each spermatid of a group developing synchronously is attached by a cytoplasmic strand to a common nutrient protoplasmic mass. This mass contains mitochondria and yolk bodies but is ...
Mammalian sperm acrosomes contain a trypsin-like protease called acrosin which causes limited and specific hydrolysis of the extracellular matrix of the mammalian egg, the zona pellucida. Acrosin was localized on hamster, guinea-pig and human sperm using monoclonal and polyclonal antibodies to human acrosin labelled with colloidal gold. This was visualized directly with transmission electron mi...
OBJECTIVE Sperm preparation techniques select sperm population with improved sperm motion characteristics. We sought to determine whether the swim-up technique selects spermatozoa with the ability to undergo hypoosmotic swelling, and how swim-up and subsequent capacitation affect the acrosome reaction rate. METHODS Semen specimens from 15 normal donors were divided into unprocessed, swim-up, ...
Membrane fusion events are required in three steps in sea urchin fertilization: the acrosome reaction in sperm, fusion of the plasma membrane of acrosome-reacted sperm with the plasma membrane of the egg, and exocytosis of the contents of the egg cortical granules. We recently reported the involvement of a Zn2+-dependent metalloendoprotease in the acrosome reaction (Farach, H. C., D. I. Mundy, ...
This study was designed to analyze boar sperm to compare motility, acrosome morphology, viability and ATP by various preservation methods between Duroc boar A with cold shock resistance sperm and Duroc boar B with cold shock sensitivity sperm. Semen volume, sperm concentration, motility and normal acrosome between Duroc boar A and B did not show any differences within 2 h after collection. Ther...
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