Seminal fluids are known to have a variety of effects on rival sperm, but in externally fertilizing species it is still unclear what effects seminal fluid can induce under sperm competition. We recorded sperm activity from natural ejaculates (including own seminal fluid) of an external fertilizer, the Arctic charr (Salvelinus alpinus), after activation either in water (the natural medium for mi...

Background The role of calcium in physiological phenomenona such as sperm acrosome reaction and hyper-activation has been well known. Calcium ionophore A23187 is routinely used for induction of acrosome reaction in mammalians sperm. Therefore, we decided to evaluate the effect of calcium ionophore A23187 on the sperm hyper-active motility patterns. MaterialsAndMethods Ten semen samples from ind...

Spermiogenesis is a series of poorly understood morphological, physiological and biochemical processes that occur during the transition of immotile spermatids into motile, fertilization-competent spermatozoa. Here, we identified a Serpin (serine protease inhibitor) family protein (As_SRP-1) that is secreted from spermatids during nematode Ascaris suum spermiogenesis (also called sperm activatio...

the objective of the research was to test the effect of iron and aluminium coagulants commonly used for lake re-cultivation, on the pike sperm motility and fertilisation. the coagulants caused changes in the analyzed hydrochemical parameters of the water such as: fe, mg2+, tss, so42- and cl-. selected parameters of sperm motility: mot, vcl, vsl, vap, lin were estimated using casa. the sperm mot...

Boar spermatozoa were prepared for intracytoplasmic sperm injection (ICSI) by two different treatments to facilitate sperm chromatin decondensation and improve fertilisation rates after ICSI in pigs: spermatozoa were either frozen and thawed without cryoprotectants, or treated with progesterone. Morphological changes of the sperm heads after the treatments were examined and then the activation ...

Mitochondria activation factor (MAF) is a high-molecular-weight polyphenol purified from black tea that activates mitochondrial respiration. It increased the mitochondrial membrane potential and motility of sea urchin sperm, by up to 8%, to the same extent as sperm-activating peptides (SAPs) secreted by the egg. Unlike SAPs, MAF had no effect on sperm swimming behavior, suggesting that the mech...

Results of several lines of experimentation suggest that sperm-induced egg activation has several features in common with G protein-coupled receptor signal transduction mechanisms. We report that microinjection of GDP beta S into metaphase II-arrested mouse eggs blocks sperm-induced egg activation. Since GDP beta S inactivates both heterotrimeric and monomeric classes of G proteins, the involve...

Intracytoplasmic sperm injection (ICSI) has increased the potential of the assisted reproductive technologies to propagate mammalian species and has provided an opportunity for research into cell cycle control and the mechanisms involved in sperm-induced oocyte activation. We have investigated the efficacy of ICSI in the rhesus monkey, the mechanism of fertilization following sperm injection an...

A B S TRACT The early events of fertilization that precede and cause activation of an egg have not been fully elucidated. The earliest electrophysiological change in the sea urchin egg is a sperm-evoked increase of the egg's membrane conductance. The resulting depolarization facilitates entry of the fertilizing sperm and precludes the entry of supernumerary sperm. The sequence of the increase i...