When females are sexually promiscuous, sexual selection continues after insemination through sperm competition and cryptic female choice, and male traits conveying an advantage in competitive fertilization are selected for. Although individual male and ejaculate traits are known to influence paternity in a competitive scenario, multiple mechanisms co-occur and interact to determine paternity. T...

Received: 21 January, 2014 Accepted: 30 March, 2014 Published: 20 April, 2014 A study was conducted to investigate the effect Gonadotropins supplied to culture medium on human sperm parameters and sperm DNA structure during in vitro sperm activation. Thirty infertile patients were included. Semen sample was divided into 3 aliquots. One mL of SMART medium either alone (control group) or supplied...

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...

Sperm show patterns of rapid and divergent evolution that are characteristic of sexual selection. Sperm competition has been proposed as an important selective agent in the evolution of sperm morphology. However, several comparative analyses have revealed evolutionary associations between sperm length and female reproductive tract morphology that suggest patterns of male-female coevolution. In ...

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)....

To gain fertilizing capacity, mammalian sperm should reside in the female tract for a period of time. The physiological changes that render the sperm able to fertilize are known as capacitation. Capacitation is associated with an increase in intracellular pH, an increase in intracellular calcium, and phosphorylation of different proteins. This process is also accompanied by the hyperpolarizatio...

The number and distribution of sperm in the sperm storage tubules (SSTs) in the uterovaginal junction (UVJ) of the Zebra Finch (Poephila guttata) oviduct was examined under three copulation patterns: single insemination, multiple insemination by the same male, and multiple insemination by two males in sequence. The proportion of SSTs containing sperm varied markedly between birds (range = 22-99...

Objective: Using correlation analysis between the sperm spontaneous acrosome reaction rate (SARR) and routine semen parameters in male infertility patients, we explored the value of the sperm spontaneous acrosome reaction in the evaluation of sperm functions. Methods: The participants comprised of 219 male infertility patients who had visited the Center for Reproductive Medicine, Shandong Unive...

Proteomic studies of spermatozoa have identified a large catalog of integral sperm proteins. Rapid evolution of these proteins may underlie adaptive changes of sperm traits involved in different events leading to fertilization, although the selective forces underlying such rapid evolution are not well understood. A variety of selective forces may differentially affect several steps ending in fe...

Female sperm storage is common among organisms with internal fertilization. It is important for extended fertility and, in cases of multiple mating, for sperm competition. The physiological mechanisms by which females store and manage stored sperm are poorly understood. Here, we report that the biogenic amines tyramine (TA) and octopamine (OA) in Drosophila melanogaster females play essential r...