Exogenous hyalin and sea urchin gastrulation. Part IV: a direct adhesion assay - progress in identifying hyalin's active sites.

In Strongylocentrotus purpuratus the hyalins are a set of three to four rather large glycoproteins (hereafter referred to as 'hyalin'), which are the major constituents of the hyaline layer, the developing sea urchin embryo's extracellular matrix. Recent research from our laboratories has shown that hyalin is a cell adhesion molecule involved in sea urchin embryo-specific cellular interactions. Other laboratories have shown it to consist of 2-3% carbohydrate and a cloned, sequenced fragment demonstrated repeat domains (HYR) and non-repeat regions.

Hyalin is a cell adhesion molecule involved in mediating archenteron-blastocoel roof attachment.

The US National Institutes of Health has designated the sea urchin embryo as a model organism because around 25 discoveries in this system have led to insights into the physiology of higher organisms, including humans. Hyalin is a large glycoprotein in the hyaline layer of sea urchin embryos that functions to maintain general adhesive relationships in the developing embryo. It consists of the hyalin repeat domain that has been identified in organisms as diverse as bacteria, worms, flies, mice, sea urchins and humans.

Phototactic responses to ultraviolet and white light in various species of Collembola, including the eyeless species, Folsomia candida.

Previous observations have indicated homology in the cellular components between Collembolan eyes and the compound eyes of insects. However, behavioral or physiological studies indicating similarities in function are lacking. Collembolan eyes were examined from three species in the Family Isotomidae using scanning electron microscopy.