Two distinct types of surface membrane rearrangement occur during the differentiation of Caenorhabditis elegans spermatids into amoeboid spermatozoa. The first, detected by the behavior of latex beads attached to the surface, is a nondirected, intermittent movement of discrete portions of the membrane. This movement starts when spermatids are stimulated to differentiate and stops when a pseudop...

Mammalian spermatogenesis is a well-organized process of cell development and differentiation. Meiosis expressed gene 1 (MEIG1) plays an essential role in the regulation of spermiogenesis. To explore potential mechanisms of MEIG1's action, a yeast two-hybrid screen was conducted, and several potential binding partners were identified; one of them was membrane occupation and recognition nexus re...

Spermatogenesis consists broadly of three phases: proliferation of diploid germ cells, meiosis, and finally extensive differentiation of the haploid cells into effective delivery vehicles for the paternal genome. Despite detailed characterization of many haploid developmental steps leading to sperm, only fragmentary information exists on the control of gene expression underlying these processes...

Spermiogenesis and ultrastructure of mature spermatozoon of the caryophyllidean cestode Hunterella nodulosa, a parasite of suckers (Catostomidae), have been studied by transmission electron microscopy. This monozoic tapeworm is unique in its mode of attachment and represents the second North American species studied. The process of spermiogenesis of H. nodulosa follows the general pattern alrea...

As the number of spermatozoal characters being described in reptiles increases, it is important to detail the ontogeny of the features leading to the mature morphology of the spermatozoa which may give rise to more comprehensive data matrices for future phylogenetic analyses within the Reptilia. Therefore, spermiogenically active testes from Anolis lineatopus were investigated ultrastructurally...

Spermiogenesis in mammals is the process by which the newly formed products of meiosis, haploid spermatids, undergo a dramatic morphological transformation from round cells into flagellated spermatozoa. The underlying genetic control of spermiogenesis is complicated and not well-characterized. We have used forward genetic screens in mice to illuminate the mechanisms of spermatozoon development....

During each life cycle, gametes must preserve and pass on both genetic and epigenetic information, making the germline both immortal and totipotent. In the male germline the dramatic morphological transformation of a germ cell through meiosis, into a sperm competent for fertilization, while retaining this information is an incredible example of cellular differentiation. This process of spermato...