Nørum Ulrik, Bondgaard Morten, Pedersen Thomas V, Bjerregaard Poul
Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
Aquat Toxicol. 2005 Mar 25;72(1-2):29-44. doi: 10.1016/j.aquatox.2004.11.021. Epub 2004 Dec 30.
The effect of moult stage on cadmium accumulation and distribution was investigated in vivo in male shore crabs Carcinus maenas exposed to 1 mg Cd l(-1) for 7 days. The accumulation of cadmium in all tissues examined was markedly higher in postmoult (A(1-2) and B(1-2)) compared to intermoult (C1, C3 and C4) and premoult (D(0-3)). In addition, elevated levels of cadmium were found in gills of late premoult (D(2-3)) animals. The total amount of cadmium accumulated in the tissues (haemolymph, gills, midgut gland and muscle) increased from 43 microg Cd in early premoult (D(0-1)) to 391 microg Cd in late postmoult (B(1-2)). Gills and midgut gland were the primary cadmium accumulating tissues in C4-intermoult and premoult (D(0-3)); in early postmoult (A(1-2)) haemolymph and midgut gland were the main cadmium containing tissues, while midgut gland dominated in late postmoult (B(1-2)) and early intermoult (C1 and C3). A detailed account of calcium distribution in haemolymph, gills, midgut gland, muscle and exoskeleton during the moult cycle is presented. Mechanistic links between cadmium and calcium uptake in posterior gills of C4-intermoult and early postmoult (A(1-2)) crabs were explored using an in vitro gill perfusion technique. Calcium and cadmium influxes were markedly higher in postmoult compared to intermoult. No differences between intermoult and postmoult effluxes were found for either calcium or cadmium. From intermoult to postmoult net influx increased from 2.4 to 29 micromol Ca2+ g(-1) ww(gill) h(-1) and from 0.24 to 25 nmol Cd2+ g(-1) ww(gill) h(-1). The results indicate that the postmoult increase in cadmium influx is due to increased active transport of cadmium, at least partly, by accidental uptake via calcium transporting proteins. The in vitro net influx rates corresponded accurately to the observed in vivo accumulation of both cadmium and calcium. Although cadmium accumulation and distribution are clearly linked to changes in calcium requirements, cadmium did not interfere with calcium accumulation or distribution at any stage during the moult cycle.
研究了蜕皮阶段对暴露于1 mg Cd l(-1) 7天的雄性滨蟹体内镉积累和分布的影响。与蜕皮间期（C1、C3和C4）和蜕皮前期（D(0-3)）相比，蜕皮后期（A(1-2)和B(1-2)）所有检测组织中的镉积累明显更高。此外，在蜕皮前后期（D(2-3)）动物的鳃中发现镉水平升高。组织（血淋巴、鳃、中肠腺和肌肉）中积累的镉总量从蜕皮前期早期（D(0-1)）的43 μg Cd增加到蜕皮后期后期（B(1-2)）的391 μg Cd。在C4蜕皮间期和蜕皮前期（D(0-3)），鳃和中肠腺是主要的镉积累组织；在蜕皮后期早期（A(1-2)），血淋巴和中肠腺是主要的含镉组织，而在蜕皮后期后期（B(1-2)）和蜕皮间期早期（C1和C3），中肠腺占主导地位。本文详细描述了蜕皮周期中血淋巴、鳃、中肠腺、肌肉和外骨骼中钙的分布情况。利用体外鳃灌注技术探讨了C4蜕皮间期和蜕皮后期早期（A(1-2)）蟹后鳃中镉和钙摄取之间的机制联系。与蜕皮间期相比，蜕皮后期钙和镉的流入明显更高。对于钙或镉，蜕皮间期和蜕皮后期的流出没有发现差异。从蜕皮间期到蜕皮后期，净流入从2.4增加到29 μmol Ca2+ g(-1) ww（鳃）h(-1)，从0.24增加到25 nmol Cd2+ g(-1) ww（鳃）h(-1)。结果表明，蜕皮后期镉流入的增加至少部分是由于镉的主动运输增加，通过钙转运蛋白的意外摄取。体外净流入率与体内观察到的镉和钙的积累准确对应。尽管镉的积累和分布明显与钙需求的变化有关，但在蜕皮周期的任何阶段，镉都不会干扰钙的积累或分布。
