Comparative analysis of the neck region in spermatids and spermatozoa of some orthopteran insects.

The ultrastructure of the neck region and the participation of noncovalent and disulphide bonds in the head-tail attachment were analyzed in spermatids and spermatozoa of some orthopteran species from the families Tettigoniidae and Acrididae. This study combined conventional electron microscopy with cytochemical procedures to detect acidic proteins and lysine-rich basic proteins, and with treatments using the disruptive agents sodium dodecyl sulfate (SDS) and dithiothreitol (DTT). The organization of the neck region differs in spermatozoa among species in the families analyzed. In Acrididae the neck consists of the beginning of the axoneme attached to the nuclear envelope and surrounded by the centriolar adjunct material. Tettigoniidae species possess a complex organization in the form of a laminar "connective piece," which shows a high content of lysine-rich and acidic proteins. Experiments using SDS and DTT demonstrate that in Acrididae the head-tail connection is strong, with both noncovalent and disulphide bonds important in maintenance of the attachment. In Tettigoniidae, however, despite the presence of a morphologically well organized connective piece, the head-tail attachment is biochemically labile in comparison to that of Acrididae. The relationships between the morphology of these neck structures and their stability mediated by noncovalent and/or disulphide bonds are discussed.