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...

OBJECTIVE To determine whether gonad shields are correctly positioned on the pelvic radiographs of children with slipped capital femoral epiphysis. DESIGN Retrospective study of radiographs taken of children treated by in situ pinning of slipped capital femoral epiphysis between 1 January 1983 and 31 December 1988. SETTING Three teaching hospitals in north west England. PATIENTS 32 patien...

The gonad of jellyfish (RhopilemaesculentumKishinouye), containing high protein content with a rich amino acid composition, is suitable for the preparation of bioactive peptides. Jellyfish gonad was hydrolysed with neutral protease to obtain jellyfish gonad protein hydrolysate (JGPH), which was then purified sequentially by ultrafiltration, gel filtration chromatography, and RP-HPLC. The peptid...

Sea urchin gonad (roe) is a highly valued food in Japan and North America. Gonad price is strongly influenced by quality, with appearance, especially colour being a major determinant. Previous attempts to extract a carotenoid profile from the New Zealand sea urchin species Evechinus chloroticus have been challenging due to the large amount of lipid present in the gonad. A carotenoid extraction ...

BACKGROUND In Drosophila, the gonads are composed of two cell populations: the germ line, derived from the pole cells, and a somatic component, derived from the mesoderm of abdominal segments 5-8. Formation of the gonad requires the function of a specific homeotic gene, abdominal-A (abd-A). Other genes of the bithorax complex, Ultrabithorax (Ubx) or Abdominal-B (Abd-B), cannot substitute for th...

We examined the effects of atrazine and imazalil, 2 commonly used pesticides, on sexual differentiation in chickens. Atrazine and imazalil were injected into fertile eggs on d 0. At hatching, sex genotype and phenotype were determined. Gonads were stereomicroscopically and histologically observed. In ovo exposure of atrazine (0.01 to 3 mg/egg) did not influence hatchability, whereas imazalil ex...

Hormonal control of post-embryonic morphogenesis is well established, but it is not clear how differences in developmental endocrinology between species may underlie animal diversity. We studied this issue by comparing metamorphic thyroid hormone (TH) physiology and gonad development across spadefoot toad species divergent in metamorphic rate. Tissue TH content, in vitro tail tip sensitivity to...

At the initial stages of sex differentiation (7.5 and 8.5 days of incubation), chick embryo gonads were treated directly with testosterone or estradiol-17 beta in organ cultures. Chemically-defined media containing cholesterol as a steroid precursor were used. The differentiation of gonads in the 10 to 12-day controls, cultured in media containing no hormones, was close to that of gonads of equ...