The reproductive strategies of the sea urchin, Paracentrotus lividus, was studied in the Bay of Tunis. Samples were collected monthly, from September 1993 to August 1995, in two sites which differ in their marine vegetation and their exposure to wave action. Histological examination demonstrated a cycle of gametogenesis with six reproductive stages and a main breeding period occurring between A...

MicroRNAs (miRNAs) are small non-coding RNA molecules that play key roles in the regulation of development processes of many tissues and organs at the post-transcriptional level. However, little is known about how they affect chicken gonadal development. We examined the expression of four miRNAs (miR-218, -200b, -196, and -206) in chicken embryonic gonads at embryonic days 3.5-6.5. Their target...

We compared the temporal dynamics of gametogenesis in diploid and triploid Pacific oysters (Crassostrea gigas) using histology. Oysters were reared in an estuarine farming site in Brittany over 3 years and their gametogenesis was monitored over the exceptionally hot summer of 2003. Both diploids and triploids showed active gametogenesis, but a high proportion of triploids remained at early stag...

Autoimmune gonad destruction was induced in Atlantic salmon of both sexes in trials carried out on fish kept in sea cages on a fish farm. Damage to gonads was only found in fish where the first injection of gonad extract had been given together with Complete Freund's Adjuvant, injections without adjuvant or with carrageenan as an adjuvant were unsuccessful. Length and weight differences between...

After their arrival in the fetal gonad, mammalian germ cells express E-cadherin and are found in large clusters, similar to germ cell cysts in Drosophila. In Drosophila, germ cells in cysts are connected by ring canals. Several molecular components of intercellular bridges in mammalian cells have been identified, including TEX14, a protein required for the stabilization of intercellular bridges...

During development, complex organs are formed from individual cells and simple tissues. Organogenesis is characterized by many cellular behaviors, including cell migration, modification of cell contacts, changes in cell shape, cell proliferation and cell death. Extensive communication between cells ensures that different cell types act together in a coordinated manner to form a properly pattern...

BACKGROUND The natural sex reversal severely affects the sex ratio and thus decreases the productivity of the rice field eel (Monopterus albus). How to understand and manipulate this process is one of the major issues for the rice field eel stocking. So far the genomics and transcriptomics data available for this species are still scarce. Here we provide a comprehensive study of transcriptomes ...

The formation of testes or ovaries in the mammalian embryo is critical in determining sexual identity and the ability to reproduce. Recent studies have begun to illuminate the cellular signalling events required for development of functional testes.

JANUARY 2009 I REVIEW OF ENDOCRINOLOGY I 19 C ushing’s syndrome is the clinical manifestation of glucocorticoid excess. When the most common cause, exogenous glucocorticoid intake, is excluded, one is left with a group of disorders in which a tumor (or rarely hyperplastic tissue) either produces excess cortisol or stimulates excess cortisol production indirectly through overproduction of either...

Over the last 20 years, the zebrafish has become a powerful model organism for understanding vertebrate development and disease. Although experimental analysis of the embryo and larva is extensive and the morphology has been well documented, descriptions of adult zebrafish anatomy and studies of development of the adult structures and organs, together with techniques for working with adults are...