Although it is generally understood that the testes recruited kidney ducts for reproductive function during the evolution of vertebrates, little is understood of the biological significance of the adaptation. In the context of the evolution of the mammalian epididymis, this report provides evidence that a major role of the epididymis is to enhance a male's chance of achieving paternity in a com...

This study was designed to investigate the characteristics of acrosomal changes during capacitation of bovine spermatozoa in relationship to in vitro fertility of individual bulls. Motile spermatozoa were separated from frozen-thawed semen by a swim-up procedure and capacitated in IVF-TALP medium with or without heparin. The spermatozoa were evaluated in terms of acrosomal changes at 0, 3, 4, 5...

Tyrosine nitration is a widely used marker of peroxynitrite (ONOO-) produced from the reaction of nitric oxide (NO.) with superoxide (O2(.-)). Since human spermatozoa are able to produce both NO. and O2(.-) during capacitation in vitro, we investigated whether spontaneous tyrosine nitration of proteins occurs in human spermatozoa and evaluated the physiological effects of peroxynitrite on sperm...

REČKOVá, Z., MACHATKOVá, M., RyBář, R., MáCHAL, L.: Monitoring of chromatin integrity changes in the population of motile bovine sperm capacitated in vitro. Acta univ. agric. et silvic. Mendel. Brun., 2007, LV, No. 2, pp. 65–70 The objective of our study was to standardize a method for chromatin integrity assessment in a separated population of bovine sperm and monitor the changes occurring dur...

Cannabinoids, the main active components of marijuana, have been shown to exert different adverse effects on male reproduction both in vertebrates and invertebrates. The main effects of endocannabinoids, a particular group of endogenously produced cannabinoids, in sperm are the inhibition of motility, capacitation and acrosome reaction, all fundamental processes necessary for oocyte penetration...

Sialic acids (Sias) mediate many biological functions, including molecular recognition during development, immune response, and fertilization. A Sia-rich glycocalyx coats the surface of sperm, allowing them to survive as allogeneic cells in the female reproductive tract despite female immunity. During capacitation, sperm lose a fraction of their Sias. We quantified shed Sia monosaccharides rele...

This paper argues that Information Technology (IT) needs to be demystified, through critical consciousness, for educators to focus on IT as a means to enhance learning. It goes on to define the technical, sociohistorical and political-ideological levels of IT and to identify four theoretical constructs: tutorial, machine-as-human, tool kit and catalyst. Pervading these constructs is the underst...