Effects of water-borne copper on the Y-organ and content of 20-hydroxyecdysone in Eriocheir sinensis.
The effects of water-borne copper (Cu2+) (0.01, 0.10, 1.00, and 5.00 mg/L) on Y-organ (YO) microstructure and ultrastructure and on the content of 20-hydroxyecdysone (20-HE) in Eriocheir sinensis were studied using single gradient factor experiments. Results demonstrated that there was no significant difference in YO microstructure and ultrastructure when E. sinensis was exposed to 0.01, 0.10, and 1.00 mg/L water-borne Cu2+. However, exposure to 5.00 mg/L Cu2+ caused serious damage to the YO microstructure, with an obvious decrease in hemocoel and the disappearance of the basement membrane between cell fibers. In addition, there was an intumescence of cells around the hemocoel, the cell nucleus became enlarged or even rounded, and some cells around the hemocoel crumpled with only the cell nucleus isolated or even huddled in the hemocoel. Similarly, effects of water-borne Cu2+ on the YO ultrastructure were observed: obvious enlargement and rounding of the cell nucleus, high heterochromatinization of the nucleus chromatin, disappearance of the YO cell membrane in some severely damaged cells, and varied damage in cellular organelles, such as the disappearance of cristae in mitochondria and disruption of the nucleus membrane. The hemocyte nucleus showed considerable heterochromatinization. In addition, when the Cu2+ concentration increased, the content of 20-hydroxyecdysone (20-HE) decreased in all Cu2+ treatment groups (P < 0.05). Results of this study indicate that high water-borne Cu2+ concentration impaired the basic structure of YO, which is regarded as the secretion site of 20-HE, and hence decreased the content of 20-HE in hemolymph. Therefore, molting frequency as well as the growth of E. sinensis is inhibited when exposed to high concentrations of water-borne Cu2+.
Yang
Zhi-biao
ZB
School of Life Science, East China Normal University, Shanghai 200062, China.
Zhao
Yun-long
YL
Li
Na
N
Yang
Jian
J
Hua
Xiu-guo
XG
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D003386:Brachyura / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D003300:Copper / Q000633:toxicity*; D004441:Ecdysterone / Q000378:metabolism*; D004702:Endocrine Glands / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D008297:Male; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D015415:Biomarkers; D014874:Water Pollutants, Chemical; D004441:Ecdysterone; D003300:Copper