“…The segmentation has been confirmed in studies of gene expression (Douglass et al 1991;Winer et al 1993;Cornwall and Hann 1995;Turner et al 2006) and protein secretion (Dacheux et al 2003(Dacheux et al , 2006Gatti et al 2004).…”
Section: Division Of Labour Along the Epididymismentioning
confidence: 73%
“…1-D gels of micropuncture samples of luminal fluid collected along the epididymis of the echidna (Djakiew and Jones 1983) show a similar pattern of luminal fluid proteins collected from eutherians (Dacheux et al 2003) and marsupials (Chaturapanich et al 1992a). However, whereas clusterin is the most abundant epididymal protein in the eutheria that have been studied, including humans (Dacheux et al 2003(Dacheux et al , 2006Gatti et al 2004), the most abundant secreted protein in the platypus epididymis is lipocalin (see companion paper by Dacheux et al 2009); its homologues most closely resemble proteins in the reptilian epididymis (Morel et al 2000). Of particular interest are the proteins that are secreted by the epididymis and interact with spermatozoa to modify their function.…”
Section: Division Of Labour Along the Epididymismentioning
The present review examines whether monotremes may help to resolve three questions relating to sperm production in mammals: why the testes descend into a scrotum in most mammals, why spermatozoa are infertile when they leave the testes and require a period of maturation in the specific milieu provided by the epididymides, and why ejaculated spermatozoa cannot immediately fertilise an ovum until they undergo capacitation within the female reproductive tract. Comparisons of monotremes with other mammals indicate that there is a need for considerable work on monotremes. It is hypothesised that testicular descent should be related to epididymal differentiation. Spermatozoa and ova from both groups share many of the proteins that are thought to be involved in gamete interaction, and although epididymal sperm maturation is significant it is probably less complex in monotremes than in other mammals. However, the monotreme epididymis is unique in forming spermatozoa into bundles of 100 with greatly enhanced motility compared with individual spermatozoa. Bundle formation involves a highly organised interaction with epididymal proteins, and the bundles persist during incubation in vitro, except in specialised medium, in which spermatozoa separate after 3 h incubation. It is suggested that this represents an early form of capacitation. Abstract. The present review examines whether monotremes may help to resolve three questions relating to sperm production in mammals: why the testes descend into a scrotum in most mammals, why spermatozoa are infertile when they leave the testes and require a period of maturation in the specific milieu provided by the epididymides, and why ejaculated spermatozoa cannot immediately fertilise an ovum until they undergo capacitation within the female reproductive tract. Comparisons of monotremes with other mammals indicate that there is a need for considerable work on monotremes. It is hypothesised that testicular descent should be related to epididymal differentiation. Spermatozoa and ova from both groups share many of the proteins that are thought to be involved in gamete interaction, and although epididymal sperm maturation is significant it is probably less complex in monotremes than in other mammals. However, the monotreme epididymis is unique in forming spermatozoa into bundles of 100 with greatly enhanced motility compared with individual spermatozoa. Bundle formation involves a highly organised interaction with epididymal proteins, and the bundles persist during incubation in vitro, except in specialised medium, in which spermatozoa separate after 2-3 h incubation. It is suggested that this represents an early form of capacitation.
“…The segmentation has been confirmed in studies of gene expression (Douglass et al 1991;Winer et al 1993;Cornwall and Hann 1995;Turner et al 2006) and protein secretion (Dacheux et al 2003(Dacheux et al , 2006Gatti et al 2004).…”
Section: Division Of Labour Along the Epididymismentioning
confidence: 73%
“…1-D gels of micropuncture samples of luminal fluid collected along the epididymis of the echidna (Djakiew and Jones 1983) show a similar pattern of luminal fluid proteins collected from eutherians (Dacheux et al 2003) and marsupials (Chaturapanich et al 1992a). However, whereas clusterin is the most abundant epididymal protein in the eutheria that have been studied, including humans (Dacheux et al 2003(Dacheux et al , 2006Gatti et al 2004), the most abundant secreted protein in the platypus epididymis is lipocalin (see companion paper by Dacheux et al 2009); its homologues most closely resemble proteins in the reptilian epididymis (Morel et al 2000). Of particular interest are the proteins that are secreted by the epididymis and interact with spermatozoa to modify their function.…”
Section: Division Of Labour Along the Epididymismentioning
The present review examines whether monotremes may help to resolve three questions relating to sperm production in mammals: why the testes descend into a scrotum in most mammals, why spermatozoa are infertile when they leave the testes and require a period of maturation in the specific milieu provided by the epididymides, and why ejaculated spermatozoa cannot immediately fertilise an ovum until they undergo capacitation within the female reproductive tract. Comparisons of monotremes with other mammals indicate that there is a need for considerable work on monotremes. It is hypothesised that testicular descent should be related to epididymal differentiation. Spermatozoa and ova from both groups share many of the proteins that are thought to be involved in gamete interaction, and although epididymal sperm maturation is significant it is probably less complex in monotremes than in other mammals. However, the monotreme epididymis is unique in forming spermatozoa into bundles of 100 with greatly enhanced motility compared with individual spermatozoa. Bundle formation involves a highly organised interaction with epididymal proteins, and the bundles persist during incubation in vitro, except in specialised medium, in which spermatozoa separate after 3 h incubation. It is suggested that this represents an early form of capacitation. Abstract. The present review examines whether monotremes may help to resolve three questions relating to sperm production in mammals: why the testes descend into a scrotum in most mammals, why spermatozoa are infertile when they leave the testes and require a period of maturation in the specific milieu provided by the epididymides, and why ejaculated spermatozoa cannot immediately fertilise an ovum until they undergo capacitation within the female reproductive tract. Comparisons of monotremes with other mammals indicate that there is a need for considerable work on monotremes. It is hypothesised that testicular descent should be related to epididymal differentiation. Spermatozoa and ova from both groups share many of the proteins that are thought to be involved in gamete interaction, and although epididymal sperm maturation is significant it is probably less complex in monotremes than in other mammals. However, the monotreme epididymis is unique in forming spermatozoa into bundles of 100 with greatly enhanced motility compared with individual spermatozoa. Bundle formation involves a highly organised interaction with epididymal proteins, and the bundles persist during incubation in vitro, except in specialised medium, in which spermatozoa separate after 2-3 h incubation. It is suggested that this represents an early form of capacitation.
“…These changes take place during passage through the epididymis. Important modifications of the plasma membrane structure and surface take place, with adsorption of and/or unmasking of specific proteins (29)(30)(31). Further condensation of the nuclear chromatin occurs.…”
Section: The Sperm's Life From Testis To Eggmentioning
Cytometric methodologies are becoming increasingly important in veterinary andrology as means of assessing sperm function. However, as yet, flow cytometric techniques in veterinary andrology have not kept up in sophistication with those in other areas of biology and medicine. In this brief review, we consider the present state of cytometry in andrological procedures for evaluating the fertility of domestic animal sires. We outline the aspects of sperm physiology, paying particular attention to the changes that take place during the process known as capacitation, which prepares the sperm for interaction with the egg. We then examine briefly but critically the cytometric techniques that are currently in commercial use or are being established in research laboratories for testing sperm characteristics. Current limitations and potential developments in semen assessment are discussed. Recent research knowledge offers possibilities for applying more subtle flow cytometric approaches to distinguish different levels of fertilizing potential in semen samples. For example, linking field fertility data to multiparametric kinetic studies of sperm capacitational changes rather than ''single parameter-single time point'' estimations may reveal that slower rather than rapid changes indicate high fertility. Moreover, the development of multicolor flow cytometric procedures as a means of evaluating multiple functional parameters in individual cells would reduce the uncertainties always inherent in predicting fertility from in vitro sperm evaluation tests. ' 2011 International Society for Advancement of Cytometry Key terms fertility; sperm evaluation; heterogeneity; subpopulations; multicolour cytometry THE main focus of an andrological assessment in veterinary medicine is to ascertain the fertility of a potential sire. Although the most obvious and indeed frequently used general veterinary test is to quantify the number of offspring born to the sire, this is a lengthy and very expensive process. For ''accuracy,'' many inseminations must be carried out, and results must await gestation and birth. Obviously, therefore, development of rapid tests that can be carried out in the laboratory has for long been important. However, as research into the reproductive process has advanced, it has become clear that the life of the fertilizing sperm between its release from the testis and its fusion with the egg is far from simple. Moreover, the population of sperm ejaculated into the female has been revealed as being heterogeneous in functional ability, even if morphologically normal [c.f. reviews (1,2)]. As a result of these findings, tests are being developed to examine functional ability within a heterogeneously responding population (3-5).Given that a normal male ejaculate contains many millions of individual sperm cells, it is natural that these tests are based on cytometry. In this short review, we will outline and comment upon a range of modern and still-developing cytometric methodologies in use or potentially useful for sperm...
“…During the epididymal transit, the main morphological change that takes place in the spermatozoon is the migration of the cytoplasmic droplet, a remnant of the cytoplasm associated with testicular sperm. The droplet migrates from the proximal to the distal position during maturation and is normally shed from spermatozoa during or shortly after ejaculation [26]. Failure to extrude excess cytoplasm during sperm differentiation and maturation traps a number of enzymes, including glucose-6-phosphate dehydrogenase (G6PD) and ß-nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, which have been associated with ROS generation through the formation of the NADPH intermediate [27].…”
Oxidative stress (OS) is a condition caused by an imbalance between reactive oxygen species (ROS) overgeneration and decreased antioxidant defense mechanisms in the cell. OS has become a prominent factor in male reproductive dysfunction as ROS cause damage to sperm DNA, lipids and proteins, alterations to critical sperm structures and signaling pathways, leading to a decreased sperm activity and fertilizing capacity. At the same time, small amounts of ROS play vital roles in events leading to sperm maturation and acquisition of functional activity, which is why a proper oxidative balance is of paramount importance for a proper male fertility. Understanding the physiological and pathological roles of ROS in male reproduction has become an essential pillar of modern andrology; however, numerous questions related to the controversial behavior of ROS in male reproductive cells and tissues still remain unanswered. This chapter aims to summarize current evidence available on the relationships between free radicals, antioxidants and male reproduction and to trigger more scientific interest, particularly with respect to the design of efficient strategies to diagnose or treat male sub-or infertility associated with OS.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.