Spermatozoa development

Two important aspects of early development of the reproductive tract are that the fetal gonad is structurally indifferent in male and female embyros and that the fetal reproductive system can therefore develop as male or female. Thus, the first major step in development of the reproductive system is establishing gonadal sex. Sex of the embryo depends on whether the spermatozoon carries an X or Y chromosome, and sexual differentiation of the indifferent structures in the gonad is necessary to form the male or female reproductive tract. The SRY gene on the Y chromosome is needed for testicular... 

The development of a stem cell into cells with specialized function is called the process of differentiation. This takes place most dramatically in the development of a fetus, from the single cell formed by the fusion of one spermatozoon and one ovum to a vast array of different tissues. 

An example of the use of a highly specialised cell type to study targeted toxic effects on the cellular metabolism is the recently developed boar spermatozoon motility inhibition test (Andersson et al., 1998). The motility of a spermatozoon depends on the integrity of mitochondrial functions, and thus the action of toxins affecting the energy metabolism is very rapidly detected as reduction of motility. Other end points that can be measured are plasma membrane integrity, astrodome function, and total cellular ATP and NAD reduction. This test has been particularly useful in the detection of certain types of bacterial toxins from various enviromnental and food sources. 

Hodgson, A.N. and Reunov, A.A. (1994) Ultrastructure of the spermatozoon and spermio-genesis of the brachiopods Discinisca tenuis (inarticulate) and Kraussina rubra (articulata). Invertebrate Reproduction and Development, 25, 23-31. 

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