Prostaglandins and reproduction of the scallop Argopecten purpuratus: I. relationship with gamete development

Abstract

In order to learn about factors that influence the reproductive cycle of marine bivalves, the levels of prostaglandins (PGs) PGE 2 and PGF 2α were measured during gametogenesis in the functional hermaphrodite scallop, Argopecten purpuratus. The PGs, in extracts of gonads of these scallops, were measured by radioimmunoassay techniques on different days after an induced spawning. To verify that gametogenesis was taking place during the experimental time, each time scallops were sampled, gonadal maturation was examined by gonadal index and by qualitative and quantitative histological analysis. Quantitative analysis involved oocyte size frequency distributions and determination of cross-sectional area occupied by mature sperm. The experiment was run twice, once in winter and once in spring. A linear decrease of both PGs was detected in male and female portions of the gonads as the maturation of these proceeded. In the spring experiment, this decrease was detected in both gonadal portions, but in the winter experiment, it was detected only for the male portion and not for the female one. The histological analysis of the gonads showed that in winter, the female gametes did not mature, although the male gametes did. These results are indicative of an inverse relationship between gonadal maturity and PG levels.

Prostaglandins in non-insectan invertebrates: recent insights and unsolved problems

“…For instance, Knight et al (1999) Others, however, have taken it for granted that the product identified and quantified by EIA or RIA is only that defined by the assay (e.g. Hagar et al, 1989;Martínez et al, 1999;Tahara and Yano, 2003), despite the possibility of the presence of alternative fatty acid substrates in these animals. It must be remembered that the specificity of these assays totally depends on the antibodies used as well as the degree to which samples have been extracted prior to the assay.…”

Identification and expression profiling of Ceratitis capitata genes coding for β-hexosaminidases

“…It has been demonstrated, both in vertebrates and invertebrates, that sperm glycosidases and glycosyltransferases are the first receptors for the carbohydrates of the egg surface in early gamete recognition (Martinez et al, 2000;Mengerink and Vacquier, 2001;Koyanagi and Honegger, 2003;Zitta et al, 2006;Lyng and Shur, 2007). It is known that several other proteins of the sperm surface, such as proteases, tyrosine kinases and phospholipases, may also function as receptors for the egg coat(s) in mammals (Mengerink and Vacquier, 2001;Wassarman et al, 2001;Miller and Pitnick, 2002;Talbot et al, 2003;Shur et al, 2006).…”

Characterization of reproduction-specific genes in a marine bivalve mollusc: Influence of maturation stage and sex on mRNA expression

“…In the marine scallop A. purpuratus, the timing and duration of gonad maturation and spawning are under the control of various exogenous and endogenous factors. Martínez et al (1999Martínez et al ( , 2000 reported that the prostaglandins (PGE2 and PGF2) and the dopaminergic mechanisms, controlled by dopamine, noradrenaline, and serotonin (5-HT), play a major role in the spawning process and during gametogenesis. Recently, cyclic AMP has been shown to be involved in the regulation of reproductive processes via the phosphorylation of different kinds of proteins for each stage (Martínez and Cisterna, 2004).…”