Knowledge on the energy distribution during the reproductive cycle of the giant lion-paw scallop, Nodipecten subnodosus is limited, but necessary for aquaculture purposes. In a previous work, we found that natural food availability can sustain the full cost of gametogenesis in optimal environmental conditions. The present study analyses the lipid and sterol classes’ composition of several tissu...

INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358 Gametogenesis and fertilization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358 Inheritance of scutellum color. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

The identification of several mutations and genes involved in sporogenesis and gametogenesis has initiated a genetic framework for understanding gametophyte biogenesis. Recent advances include the molecular characterization of genes required for sporocyte formation and meiosis. These studies have revealed some unexpected interactions linking development of sporophytic cells and tissues with ini...

Germ cells are the ultimate stem cells, and reports of their in vitro derivation generate excitement due to potential applications in reproductive medicine. To date, there is no firm evidence that meiosis, the hallmark of gametogenesis, can be faithfully replicated outside of the gonad. We propose benchmarks for evaluating in vitro derivation of germ cells, facilitating realization of their pot...

Follicle-stimulating hormone (FSH) plays a central role in steroidogenesis and gametogenesis. In recent years, a great deal has been learned about the microheterogeneity of FSH using newly developed assay techniques. This review article will attempt to discuss the advantages and the limitations of recently developed and commonly used assay systems.

Adult Mytilus edulis were exposed to environmentally relevant concentrations of 17β-estradiol in seawater for 10 days. Exposure was performed to assess effects on vitellogenin mRNA expression during early gametogenesis stages. The results show an increase in VTG expression, in contrast with previous experiments where no statistically significant change in the expression of VTG in ripe mussels w...

In order to sustain lifelong production of gametes, many animals have evolved a stem cell-based gametogenic program. In the Drosophila ovary, germline stem cells (GSCs) arise from a pool of primordial germ cells (PGCs) that remain undifferentiated even after gametogenesis has initiated. The decision of PGCs to differentiate or remain undifferentiated is regulated by somatic stromal cells: speci...

TUDIES of the types of aberrations induced in chromosomes by irradiation S during the meiotic prophase have been infrequent. The complications introduced by synapsis and crossing over make the analysis much more difficult than is the case for mitotic divisions on which most of the work has been concentrated. However, in the assessment of radiation damage to genetic material, the differential se...

Fetal testis is a major target of endocrine disruptors (EDs). During the last 20 years, we have developed an organotypic culture system that maintains the function of the different fetal testis cell types and have used this approach as a toxicological test to evaluate the effects of various compounds on gametogenesis and steroidogenesis in rat, mouse and human testes. We named this test rat, mo...

Two mechanisms for chloroplast DNA replication have been revealed through the study of an unusual heteroplasmic strain of the green alga Chlamydomonas reinhardtii. Heteroplasmy is a state in which more than one genome type occurs in a mitochondrion or chloroplast. The Chlamydomonas strain spa19 bears two distinct chloroplast genomes, termed PS+ and PS-. PS+ genomes predominate and are stably ma...