IN VITRO ACTION OF COBRA VENOM ON GOAT SPERMATOZOA ULTRASTRUCTURE BY TRANSMISSION AND SCANNING ELECTRON MICROSCOPY

Crotalus durissus sp. rattlesnake venom induces toxic injury in mouse sperm

Accidents involving snakebites constitute a serious public health problem in many regions around the world. However, there are no study about a possible action of snake venom on the reproductive system. Herein we show that Crotalus durissus sp. (Linnaeus) rattlesnake venom (25 μg/kg of body weight) affected chromatin condensation, and increased the number of sperm with abnormal morphology and the sperm count. In conclusion, besides the known hazards of the C. durissus sp. venom to animal health, this study was the first to show its effect also on male germ cells.

Heads you win, tails you lose: filtration processing for the microscopical examination of sperm heads

The sperm head plays a key role in many fertilisation events and determining the precise location of molecules within the head region is important in mechanistically dissecting the fertilisation process. Such molecules may be present in low copy number and many sperm head profiles must be examined to localise them to particular subcellular structures with confidence. Filtration has traditionally been used for the purpose of concentrating biological material, such as free-living cells, spores, and subcellular fractions, and little attempt has been made to extend the procedure to encompass the entire processing schedule, mainly due to the incompatibility of intermediate dehydrating solvents with membrane filters. The novel and simple technique of filtration processing that we describe produced a dense mat of cells, with several sperm heads being visible in coronal orientation in a high-power field at the light microscopic level, and allowed positive immunocytochemical staining to be identified with confidence. This new technique exploits the low viscosity of LR White acrylic resin to allow the entire processing procedure to be undertaken in the filtration apparatus. In contrast, conventional techniques for preparing free-living cells, namely pre-embedding in a supportive matrix prior to processing, and centrifugation at each stage of the processing procedure, proved suboptimal, partly due to the final concentration that could be achieved, but mainly due to the random orientation of cells that these techniques afforded.

Sex selection of sperm in farm animals: status report and developmental prospects

Pre-selection of spermatozoa based on the relative DNA difference between X- and Y-chromosome bearing populations by flow cytometry is an established method that has been introduced into commercial cattle production. Although several important improvements have increased the sort efficiency, the fertilising ability of sexed spermatozoa based on offspring per insemination is still behind farmers' expectations. The main stress factors, especially on mitochondria, that reduce the lifespan of spermatozoa are described, and new technical as well as biological solutions to maintain the natural sperm integrity and to increase the sorting efficiency are discussed. Among these methods are the identification of Y-chromosome bearing spermatozoa by bi-functionalised gold nanoparticles and triplex hybridisationin vivoas well as new laser-controlled deflection system that replaces the deflection of spermatozoa in the electrostatic field. Additionally, as well as a new nonsurgical transfer system of spermatozoa into the oviduct of cows has been developed and allows a significant reduction of spermatozoa per transfer. Altogether, the improvements made in the recent years will allow a broader use of sex-sorted spermatozoa even in those species that require more cells than cows and sheep.