Seasonal variations in fatty acid composition in several tissues of a 1-year-old population of giant lion's-paw scallop Nodipecten subnodosus were analyzed during gonad development. Samples were taken bimonthly from December 1999 to June 2000, a period in which gonad development was occurring. Fatty acid accumulation in neutral and polar lipids of the female gonad was concomitant to the gonad d...

BACKGROUND In birds as in mammals, a genetic switch determines whether the undifferentiated gonad develops into an ovary or a testis. However, understanding of the molecular pathway(s) involved in gonad differentiation is still incomplete. METHODOLOGY/PRINCIPAL FINDINGS With the aim of improving characterization of the molecular pathway(s) involved in gonad differentiation in the chicken embr...

The structure and maturation of the male gonad of the Mediterranean vermetid gastropod Dendropoma petraeum are described. Histological sections of the gonads were made throughout development and gonad activity was monitored at regular monthly intervals. During the autumn months the gonad is very small and is surrounded by a large quantity of connective tissue; it becomes more voluminous from De...

In sex determination, globally acting genes control a spectrum of tissue-specific regulators to coordinate the overall development of an animal into one sex or the other. In mammals, primary sex determination initially occurs in the gonad, with the sex of other tissues specified as a secondary event. In insects and nematodes, globally acting regulatory pathways have been elucidated, but the mor...

Introduction: Unwanted exposure of ionizing radiation may result in carcinogenesis, cell mutations, and organ failure. High-atomic number elements such as lead, tungsten, bismuth have been traditionally used for radiation protection. Theoretical and practical studies have shown that a variety of shielding materials e.g. polymer composites (PCs) can be used for attenuation of th...

The application of microarray technology to the study of mammalian organogenesis can provide greater insights into the steps necessary to elicit a functionally competent tissue. To this end, a temporal profile of gene expression was generated with the purpose of identifying changes in gene expression occurring within the developing male and female embryonic gonad. Gonad tissue was collected fro...

Organ shape and size, and, ultimately, organ function, relate in part to the cell and tissue spatial arrangement that takes place during embryonic development. Despite great advances in the genetic regulatory networks responsible for tissue and organ development, it is not yet clearly understood how specific gene functions are linked to the specific morphogenetic processes underlying the intern...

The two parts of the Caenorhabditis elegans reproductive system, the germ cells and the somatic reproductive tissues, each influence the life span of the animal. Removing the germ cells increases longevity, and this life span extension requires the somatic gonad. Here we show that the somatic gonad and the germ cells make distinct contributions to life span determination. The life span increase...

The gonad index, GI, is widely used as a measure of changes in reproductive state. There are, however, problems with its use because it is based on the implicit assumption of an isometric relationship between gonad size and some measure of total size. If, for example, gonad weight and total weight are used, the exponent for an allometric relationship usually is ignored and hence assumed to be 1...