Ticket #5260 (new)

Opened 7 weeks ago

Type 2 Diabetes “Off Switch” Found Inside Certain Brain Cells

Reported by: "Escape Type 2 Diabetes" <Mellitox@…> Owned by:
Priority: normal Milestone: 2.11
Component: none Version: 3.8.0
Severity: medium Keywords:
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Type 2 Diabetes “Off Switch” Found Inside Certain Brain Cells



ome echinoderms brood their eggs. This is especially common in cold water species where planktonic larvae might not be able to find sufficient food. These retained eggs are usually few in number and are supplied with large yolks to nourish the developing embryos. In starfish, the female may carry the eggs in special pouches, under her arms, under her arched body or even in her cardiac stomach. Many brittle stars are hermaphrodites. Egg brooding is quite common and usually takes place in special chambers on their oral surfaces, but sometimes the ovary or coelom is used. In these starfish and brittle stars, direct development without passing through a bilateral larval stage usually takes place. A few sea urchins and one species of sand dollar carry their eggs in cavities, or near their anus, holding them in place with their spines. Some sea cucumbers use their buccal tentacles to transfer their eggs to their underside or back where they are retained. In a very small number of species, 
 the eggs are retained in the coelom where they develop viviparously, later emerging through ruptures in the body wall. In some species of crinoid, the embryos develop in special breeding bags, where the eggs are held until sperm released by a male happens to find them.

Asexual reproduction
One species of seastar, Ophidiaster granifer, reproduces asexually by parthenogenesis. In certain other asterozoans, the adults reproduce asexually for a while before they mature after which time they reproduce sexually. In most of these species, asexual reproduction is by transverse fission with the disc splitting in two. Regrowth of both the lost disc area and the missing arms occur so that an individual may have arms of varying lengths. Though in most species at least part of the disc is needed for complete regeneration, in a few species of sea stars, a single severed arm can grow into a complete individual over a period of several months. In at least some of these species, they actively use this as a method of asexual reproduction. A fracture develops on the lower surface of the arm and the arm pulls itself free from the body which holds onto the substrate during the process. During the period of regrowth, they have a few tiny arms and one large arm, thus often being referred to 
 as "comets".

Asexual reproduction by transverse fission has also been observed in adult sea

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