Fertilization membrane

Egg 65 No effect on fertilization membrane formation or development in eggs transferred 1 min after insemination 46... 

Egg Starfish, Asterias rubens 326 Irreversible inhibition of fertilization membrane formation in eggs transferred 10 sec. after insemination 46... 

In echinoderms, zinc concentrations are usually higher in detrital feeders than in carnivores, higher in surface feeders than in sediment feeders, and higher in specimens collected inshore than those collected offshore in deeper waters (Eisler 1980). Sea cucumbers, Stichopus tremulus, accumulate radiozinc-65 from seawater by a factor of 1400 however, radiozinc accumulation data should be viewed with caution because addition of stable zinc can reduce zinc-65 accumulations in echinoderm viscera up to tenfold (Eisler 1981). Zinc inhibits the formation of the fertilization membrane in sea urchin eggs, possibly by interfering with cortical granule-derived proteases and proteins (Nakamura et al. 1989). 

Nakamura, S., C. Ohmi, and M.K. Kojima. 1989. Effect of zinc ion on formation of the fertilization membrane in sea urchin eggs. Zool. Sci. (Japan) 6 329-333. 

Unlike mammalian embryos that are protected within the uterus, amphibian embryos are protected only by a fertilization membrane and jelly coat. Although there is some... 

A respiratory burst accompanies fertilization of sea urchin eggs.576 577 In this case, the burst appears to produce H202 as the major or sole product and is accompanied by release of ovoperoxidase from cortical granules. This enzyme uses H202 to generate dityrosine crosslinkages between tyrosine side chains during formation of the fertilization membrane. Defensive respiratory bursts are also employed by plant cells.578 579 See also Box 18-B. 

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