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		introduction cont. Embryos that have been treated with lithium chloride accumulate B-catenin in every cell (Gilbert, 1997). LiCl inhibits GSK-3, a B-catenin regulating molecule, leading to higher B-catenin levels (Logan et al., 1999). Developmental abnormalities in gut formation accompany increased nuclear B-catenin levels achieved with LiCl treatment. This study examined the effects of LiCl on sea urchin gastrulation by examining embryo development in different concentrations of a LiCl solution. It is expected that allowing sea urchin embryos to develop in LiCl will disturb normal vegetal cell processes due to excess B-catenin (Cameron and Davidson, 1997). Lithium has been proven to cause abnormally exaggerated development of structures derived from the vegetal area. Lithium chloride can also result in the formation of embryos with a proportionally large archenteron or even with an archenteron that bulges outward from the surface rather than invaginating properly into the blastocoel. This phenonmenon shown above is known as exogastrulation.