A variety of mechanisms are engaged in sex determination in vertebrates. The teleost fish swamp eel undergoes sex reversal naturally and is an ideal model for vertebrate sexual development. However, the importance of proteome-wide scanning for gonad reversal was not previously determined. We report a 2-D electrophoresis analysis of three gonad types of proteomes during sex reversal. MS/MS analy...

Dr. Strauss is aware of the importance to the body of the mechanisms influencing the disposal of water, although his teleology is sometimes tongue-in-cheek. In discussing diurnal variations in urine flow, "the teleologic usefulness of a diminished output of urine during the usual time of sleep requires no comment." Approximately twice as much space is devoted to thirst, water, and the antidiure...

The only hope is education, yet the limitations placed on this solution are severe. The author feels that the rightful function of education is to fit the young "to participate in their culture and to preserve it"; social change must come from the adult community, not the schools. In addition, each culture is "to have considerable respect for the past and its achievements, to rely on scrutiny a...

To determine the effects of feeding or starvation on resource allocation to body components during the reproductive cycle of Sphaerechinus granularis, sea urchins were placed in laboratory tanks and either fed ad libitum or starved during two different periods of their biological cycle, i.e. the mature stage and the recovery stage. The urchin growth was monitored over the whole experimental per...

This study attempts to look into the energetic status of demersal fish species with their maturity stages and evaluate their energetic condition. Demersal fish species from wild were captured, total length and weight of each fish were measured and gonads were observed, weighted and collected with fish flesh. Gonadosomatic index, water content of gonad and flesh and gonadal and somatic caloric v...

Female birds develop asymmetric gonads: a functional ovary develops on the left, whereas the right gonad regresses. In males, however, testes develop on both sides. We examined the distribution of germ cells using Vasa/Cvh as a marker. Expression is asymmetric in both sexes: at stage 35 the left gonad contains significantly more germ cells than the right. A similar expression pattern is seen fo...

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...

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...