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

Abstract

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.

Fluorescence microscopy study on the cytoskeletal displacements during sperm differentiation in the bush‐cricket Tylopsis liliifolia (Fabricius) (Orthoptera: Tettigoniidae)

“…The constant presence of F‐actin in the gametes from the various examined districts of T. liliifolia , however, never found in spermatozoa of other invertebrates, leads us to hypothesize, instead, the involvement of this cytoskeletal component in flagellar movements in both male and female genital tracts. It is worthy of note, moreover, the marked F‐actin positivity found immediately posterior to the nucleus, at an area corresponding to the basal body region; it cannot be excluded that the F‐actin could be a component of the pericentriolar material (also called centriolar adjunct material ), closely wrapped around the microtubules of the basal body during the spermiogenesis of several insects, including T. liliifolia (Dallai, ; Gatenby and Tahmisian ; Guerra et al, ; Jamieson, ; Paoli et al, ; Phillips, ; Viscuso et al, ; Vitale et al, ). Furthermore, this hypothesis is supported by the lacking of positivity for α‐tubulin at that area: the pericentriolar material, in fact, could prevent the specific anti‐α‐tubulin antibody from penetrating in that sperm region.…”