title: The effects of hexavalent and trivalent chromium on fertilization and development in sea urchins.
abstract: The action of Cr6+ (as chromate) and Cr3+ (as sulfate and nitrate) on fertilization and development has been investigated in sea urchins. By rearing the embryos in the presence of chromate (5 X 10(-5) to 5 X 10(-4) M), the differentiation of the gut and skeleton was severely affected. The treatment of sperm before fertilization with CrO2- 4 (10 to 30 min, 10(-4) to 10(-2) M) resulted in a number of abnormal larvae, depending on the length of exposure and the CrO2- 4 concentration. Morphological and quantitative changes of mitotic activity during cleavage were observed as a result of CrO2- 4 exposure of zygotes, as well as of sperm and egg pretreatment. The exposure of embryos to Cr3+ after fertilization permitted larval differentiation, but affected the motility and hatchability of the embryos. The pretreatment of gametes with Cr3+ never induced larval malformations. Cr3+ exerted a strong depressive action on fertilization by decreasing the fertilizing capacity of sperm and leaving the fertilizability of the eggs almost unaffected.
mesh_terms: D000818:Animals; D002840:Chromates / Q000633:toxicity*; D005260:Female; D005306:Fertilization / Q000187:drug effects*; D007814:Larva / Q000033:anatomy & histology / Q000187:drug effects; D008297:Male; D010063:Ovum / Q000648:ultrastructure; D012098:Reproduction / Q000187:drug effects*; D012617:Sea Urchins / Q000502:physiology*; D013094:Spermatozoa / Q000187:drug effects
chemical_list: D002840:Chromates