Capacitation sperm

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Hyperactivation is a dramatic change in the motility pattern of human and other mammalian sperm that occurs prior to fertilization in the female reproductive tract or in vitro. It is thought to assist the sperm in reaching the site of fertilization and penetrating the vestments of the egg. The long term goals of this project are to study the functions and control mechanisms for hyperactivation and to determine its relationship to sperm capacitation.

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Physiological 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.

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In mammals, ejaculated sperm must undergo complicated physiological and functional changes as they traverse the female reproductive tract before they can bind to the zona pellucida, undergo the acrosome reaction, and fertilize the egg. The preparatory changes are collectively referred to as capacitation. Capacitated sperm show hyperactivation, which is a specialized movement of the sperm flagellum that creates the propulsive force for the penetration of the zona pellucida.

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In the early s, Austin and Chang independently described the changes that are required for the sperm to fertilize oocytes in vivo. Following these initial and fundamental findings, a remarkable number of observations led to characterization of the molecular steps behind this process. The discovery of certain sperm-specific molecules and the possibility to record ion currents through patch-clamp approaches helped to integrate the initial biochemical observation with the activity of ion channels.

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Human Reproduction 28 1 : Study Design, Size, and Duration Semen samples were obtained from 45 fertile men aged 25— Sperm motility and hyperactivation were analyzed by a computer-assisted sperm analysis CASA system.

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The study of germline stem cells and of germline cells has deep implications for the understanding of fertility, development and cancer. Nowadays, we are experiencing the very fascinating challenge of application of —OMICS technologies to this issue, which is opening new and unexpected horizons in virtually all the branches of biology. Here, we carried out a review of signalling systems involved in maturation of male germ cells and in the process that leads them to become fully fertile.

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Capacitation is a series of morphological and metabolic changes necessary for the spermatozoon to achieve fertilizing ability. One of the earlier happenings during mammalian sperm capacitation is the production of reactive oxygen species ROS that will trigger and regulate a series of events including protein phosphorylation, in a time-dependent fashion. The identity of the sperm oxidase responsible for the production of ROS involved in capacitation is still elusive, and several candidates are discussed in this review.

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The success rate of this physiological process depends to a high degree on the ability of spermatozoa to undergo capacitation and penetrate the oocyte vestments [ 1 ]. In vivo sperm capacitation is a gradual event that is actively and progressively coordinated within succeeding segments of the female genital tract [ 2 ]. Once inside the female genital tract, other events occur in a sequential and parallel way for an extended period, such as hyperactivation, tyrosine phosphorylation Tyr-P and preparation to undergo acrosome reaction AR slow capacitation events. Numerous studies have indicated that PKA phosphorylates several substrates pPKAs which supposes the initial point either for fast or slow events of the capacitation [ 3 ].

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Sperm preparation protocols currently available for assisted conception include density gradient separation and washing methods, that are aimed at isolating and capacitating as much motile sperm as possible for subsequent oocyte fertilization. Sperm preparation in washing buffers is a very important step in maintaining the correct physiological activities of cells. Recent studies emphasized the importance of the evaluation of novel parameters, such as biochemical analysis of the endogenous content of reactive oxygen species ROS and the level of Tyr-phosphorylation of the cells, as mostly efficacy features depicting the correct status of sperm.

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A process that is used to retrieve the spermatozoa in a semen sample that have the greatest probability of fertilising. Sperm capacitation is a natural process that takes place in semen after it has been ejaculated and it is essential for fertilising the ovum. This process takes place when ejaculated semen comes into contact with the female genital tract.

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