A Simple Method For The Preparation Of Sperm Of External Fertilizers For Scanning Electron Microscopy

A simple technique is described for the study of sperm of some external fertilizers (sea urchin, Parechinus angulosus; teleost, Liza dumerili; anurans, Xenopus laevis and Bufo rangeri) by means of scanning electron microscopy. The technique involves: (i) dilution of sperm with water of the natural environment of the animals or artificial media resembling their natural environment; (ii) spreading of sperm suspension on 10-mm square Perspex plates; (iii) fixation of diluted sperm with 2.5 pH 7.4 Millonig phosphate buffered glutaraldehyde (1 hour); (iv) repeated washing in phosphate buffer, air drying and coating with palladium-gold in a vacuum evaporator. Postfixation with 1% osmium tetroxide did not improve the results and dehydration with an alcohol series was not necessary.