title: Cadmium inhibits molting of the freshwater crab Sinopotamon henanense by reducing the hemolymph ecdysteroid content and the activities of chitinase and N-acetyl-β-glucosaminidase in the epidermis.
abstract: Molting is an essential process during the growth of crustaceans, which is coordinated by ecdysteroids secreted by the Y-organ, molting inhibiting hormone secreted by the X-organ sinus-gland complex, as well as chitinase and N-acetyl-β-glucosaminidase synthesized by the epidermis. Cadmium is one of the toxic metals in the aquatic environment. However, the endocrine effects of cadmium on the molting of freshwater crabs and the underlying mechanisms are unknown. To investigate these, freshwater crabs (Sinopotamon henanense) were acutely exposed to 0, 7.25, 14.5 and 29 mg/l Cd for 3, 4, 5 days or in some experiments for 4 days after eyestalk-ablation. The concentration of hemolymph ecdysone and the activities of the molting enzymes chitinase and NAG were measured. Histological changes in the epidermal tissues were documented. Our results showed that eyestalk ablation increased the ecdysteroid content as well as the activities of chitinase and NAG, which were inhibited by cadmium in a concentration-dependent manner; histological examinations demonstrated that eyestalk ablation produced storage particles in the epidermal tissues, which was also reduced by cadmium in a concentration-dependent manner. Our data suggest that cadmium disrupts endocrine function through inhibiting the secretion of ecdysteroids by the Y-organ and altering with the regulation of chitinase and NAG activity in the epidermis. This work provides new insights into the mechanisms underlying the molting inhibition effect of cadmium on the crabs.
authors.affiliation: School of Life Science, Shanxi University, Taiyuan 030006, People's Republic of China.
authors.forename: Jixian
authors.initials: J
authors.lastname: Luo
authors.affiliation: School of Life Science, Shanxi University, Taiyuan 030006, People's Republic of China.
authors.forename: Sihui
authors.initials: S
authors.lastname: Pei
authors.affiliation: School of Life Science, Shanxi University, Taiyuan 030006, People's Republic of China.
authors.forename: Weixin
authors.initials: W
authors.lastname: Jing
authors.affiliation: Department of Biological Sciences, Nicholls State University, Thibodaux, LA 70310, USA.
authors.forename: Enmin
authors.initials: E
authors.lastname: Zou
authors.affiliation: School of Life Science, Shanxi University, Taiyuan 030006, People's Republic of China. Electronic address: lanwang@sxu.edu.cn.
authors.forename: Lan
authors.initials: L
authors.lastname: Wang
mesh_terms: D000818:Animals; D003386:Brachyura / Q000187:drug effects* / Q000502:physiology; D002104:Cadmium / Q000633:toxicity*; D002688:Chitinases / Q000378:metabolism*; D026461:Ecdysteroids / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006458:Hemolymph / Q000378:metabolism*; D006596:Hexosaminidases / Q000378:metabolism; D018978:Molting / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D026461:Ecdysteroids; D014874:Water Pollutants, Chemical; D002104:Cadmium; D006596:Hexosaminidases; D002688:Chitinases
keywords: Chitinase; Endocrine disrupting compounds; Heavy metals; Molting hormone; N-Acetyl-β-glucosaminidase