Previously, we have identified a calcium-binding protein that is specifically expressed in spermatids and localized to the flagella of the mature sperm in mouse, so-called mCABS1. However, the physiological roles of CABS1 in the male reproductive system have not been fully elucidated yet. In the current study, we aimed to localize and clarify the role of CABS1 in porcine (pCABS1). We determined...

Caudal epididymal spermatozoa of golden hamsters were incubated in capacitation medium. Their movement patterns changed as they became hyperactivated and underwent the acrosome reaction. To understand the basic mechanism by which changes in movement pattern are brought about, digital image analysis was carried out on the flagellar movements recorded with a video system. The degree of flagellar ...

Antibodies to alpha and beta subunits of guanine nucleotide regulatory proteins (G proteins) were used to identify which G proteins are present in mature human spermatozoa and to determine their subcellular localization. Immunoblots of membranes from spermatozoa demonstrate the presence of Galphai2, Galphai3, Galphaq/11 and Gbeta35 and the absence of Galphai1, Galpha0, Galphas, Galpha12, Galpha...

Recently, the conception rates after artificial insemination have been pointed out to decline continuously. To overcome this problem, the control of frozen and thawed sperm quality is required. However, the mechanism of bovine sperm functional regulation is still largely unknown. In mammals, the ejaculated sperm are capable of showing fertilizing ability during migration in the female reproduct...

Spermatozoa are highly polarised cells with a compartmentalised distribution of lipids and proteins in their plasma membrane. It is not known how these compartments are stably maintained in what is essentially a fluid environment. In this investigation we have examined the hypothesis that intramembranous diffusion barriers selectively retain some components within compartments, while allowing f...

Mammalian fertilization involves various steps in which the participation of specific enzymes has been demonstrated by numerous studies. Acrosin is one of the most widely acrosomal protease in mammalian spermatozoa studied, including bovine; however, other proteases have also been described. A new trypsin-like serine protease named bovine serine protease of 120 kDa (BSp120) and its pre-cursor B...

Atrial natriuretic peptides (ANPs) from several species induced the human acrosome reaction. The maximal response was highest for human ANP (18.6% above unstimulated or baseline values) and decreased progressively for peptides derived from animals lower on the phylogenetic scale. ANP concentrations required for a half-maximal effect in noncapacitated spermatozoa ranged from 0.07 to 0.38 nM. ANP...

We evaluated the presence and role of internal calcium stores in human uncapacitated spermatozoa by determining the effects of two inhibitors of Ca2+ ATPase of the sarco-endoplasmic reticulum (SERCA-ATPase), thapsigargin and cyclopiazonic acid (CPA) on intracellular calcium concentrations, [Ca2+](i), plasma membrane potential and acrosome reaction. Using a fluorescent conjugate of thapsigargin,...

The egg jelly of the starfish Asterias amurensis was separated into the fractions J1, J2, and J3 on a Sephadex G-100 column. The Jl fraction induced the acrosome reaction and J2 induced sperm agglutination. Chemical analysis and chromatography revealed that sperm agglutinin is similar to asterosaponin A.

Gene disruption experiments have proven that the acrosomal protein IZUMO1 is essential for sperm-egg fusion in the mouse. However, despite its predicted function, it is not expressed on the surface of ejaculated spermatozoa. Here, we report the dynamics of diffusion of IZUMO1 from the acrosomal membrane to the sperm surface at the time of the acrosome reaction, visualized using a fluorescent pr...