Spermatogenesis in the archaic hydrothermal vent bivalve,Bathypecten vulcani,and comparison of spermatozoon ultrastructure with littoral pectinids

Summary

Bathypecten vulcani is considered a relict species from the Paleozoic, based on shell characteristics such as the presence of calcite prisms. To date, it is the only pectinid species reported from hydrothermal ecosystems. Histological and ultrastructural studies show that spermatogenesis is identical to that of littoral pectinids. The spermatozoon has a 2.7 μm long pyriform head and a 40 μm flagellum. The four mitochondria of the mid-piece are about 1.2 μm in diameter. The nucleus contains dense chromatin fibres and possesses a wide, shallow (0.1 μm) anterior fossa and a narrow, deeper (0.2 μm) posterior nuclear fossa. Comparison of the ultrastructural characteristics of the spermatozoon of B. vulcani with those of littoral pectinids shows that they can be used as a diagnostic feature of this species. In particular, its acrosome characters will be a useful complement to the shell characters in the study of the phylogenetic position of this species in relation to other pectinids.     

HeLa ribosomal protein S6. Insulin and dibutyryl cyclic AMP affect different phosphopeptides

Tryptic phosphopeptides from HeLa ribosomal protein S6 have been separated by chromatography, followed by electrophoresis. Three phosphopeptides were found in S6 from cells treated in vivo with dibutyryl cAMP and at least four different phosphopeptides were found from cells treated with insulin plus the essential amino acids. Only phosphoserine was found in S6 isolated from insulin-treated cells.     

Control of ribosomal protein phosphorylation in HeLa cells

The effects of a large series of hormones, cyclic nucleotides and metabolic inhibitors on phosphorylation of ribosomal protein S6 in HeLa cells suggest that at least two metabolic pathways are involved. One responds to insulin and epidermal growth factor; the other responds to adenosine 3′, 5′-cyclic monophosphate. Some phosphodiesterase inhibitors can suppress the phosphorylation of S6 that ordinarily is stimulated by insulin.     

Double-label autoradiography for comparison of complex protein mixtures after gel electrophoresis.

Comparison of complex protein mixtures by high-resolution, two-dimensional polyacrylamide gel electrophoresis is simplified by coelectrophoresis of ³H-labeled and ¹⁴C-labeled preparations, followed by two-step autoradiography. Both qualitative and quantitative comparisons are possible. Applications to genetics, molecular evolution, and metabolism are described.