Camp Biochenl. Physiol. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Vol. 94C, No. I, pp, 63-70, 1989 0306-4492/89 $3 00 + 0 00 Prmted m Great Brttam Pergamon Press plc CADMIUM BIOACCUMULATION AND EFFECTS ON SOLUBLE PEPTIDES, PROTEINS AND ENZYMES IN THE HEPATOPANCREAS OF THE SHRIMP CALLIANASSA TYRRHENA A. A. THAKER* and A. A. HARITOS~ Zoological Laboratory, Faculty of Sciences, University of Athens, GR 157 84 Athens, Greece (Tel. 7243-244) (Received 12 December 1988) Abstract-l. Callianassa ty rrhena shrimps were exposed to 0.2-0.8 mg Cd/l of sea-water for 2-8 days and hepatopancreas extracts were analysed. 2. Cadmium accumulation was dose- and time-dependent with the metal concentration being 7-12 times higher in hepatopancreas than in the total of the rest of body tissues. 3. Soluble cadmium was found bound to proteins of apparent molecular size > 70,000, 15,000 and 7500; the latter two being the major forms in the presence of 2-mercaptoethanol. 4. Cadmium caused significant changes in the protein components of tissue extracts observed by electrophoresis and RP-HPLC techniques. 5. In vitro, cadmmm inhtbited glutathione S-transferase and esterase activity. In contrast, m CIUO, cadmium caused a dose-dependent increase in activity of the above enzymes. For esterases, this was caused by the differential activation of multiple molecular forms. 6. Cadmium affected differently alkaline phosphatase activity in r~ioo with an increase at low- and a decrease at high-metal concentrations. INTRODUCTION Cullianussa ty rrhena is an ecologically important and widely distributed shallow water shrimp which has a potential for economic exploitation as it is used as ban for commercially important edible fish (Ahsanullah et al., 198 1 a). Crustacean hepato- pancreas is a vital and major organ in diverse metabolic activities such as synthesis and secretion of digestive enzymes, uptake of nutrients, excretion, lipid and carbohydrate metabolism and storage of inorganic reserves (for a review see Gibson and Barker, 1979). High levels of cadmium have been identified in the hepatopancreas suggesting an im- portant role in the detoxification of this metal (Topping, 1973; Overnell and Trewhella, 1979; Davies et al., 1981; Bjerregaard, 1982; Engel and Breuwer, 1986). The mechanism of cadmium toxicity is not clear yet, although the toxic effects of cadmium in crustaceans including Cullianassa sp. are well documented (Ahsanullah et al., 1981a, 1981b). Bio- chemical parameters studied so far for the effects of cadmium in crustacean species are mainly focused on the synthesis and properties of metal-binding proteins (Engel and Brouwer. 1986; Lyon er al., 1983; Lerch et al., 1982) with little information on other soluble protein components (Almar et al., 1987; Gould, 1980). Biochemical responses are likely to be among the first manifestations of excess metal accumulation and *Current address: Department of Biology, College of Science, University of Salah-Eddine, Erbil, Iraq. tTo whom correspondence should be addressed. possibly the most sensitive indicators of stress. Such early and reliable indicators of pollution are in urgent need for creating standards and guidelines to follow in marine environmental management. With these views in mind the effects of accumulated cadmium to diverse biochemical parameters of protein nature were studied in the hepatopancreas of the shrimp C. ty rrhena. MATERIALS AND METHODS Cadmium treatment of animals and tlssue exlraction The specimens of the sediment dwelling shrimp Cal- lianassa ty rrhena were collected from Vravrona Bay in South Evoikos. The animals were collected by a method described by Manning (1975) by a pump made from plastic tube (1OOcm x 7cm i.d.), equipped with a plunger. The sucked contents were emptied into a sieve. Only medium size shrimps (0.54.8 g) were kept. Of the two chela, the larger one was cut off to protect the shrimps from attacking each other. The animals were transfered to the laboratory where they were kept in plastic boxes (11 x 11 x 4 cm), containing 400 ml of synthetic sea-water of approximately 38%3 salinity. Five individuals were kept in each container. The animals were maintained under controlled photoperiods of 12 hr light/l2 hr darkness. The temperature was kept constant at 12 & 0.5”C. The water of each container was replaced every second day. No food was provided. Dead shrimps were removed twice daily. Cadmium was added in the form of CdCl,, 24 hr after bringing the animals to the laboratory. Control anrmals were kept under the same conditions and time periods without any addition of metal. Hepatopancreas of control and exposed to cadmium animals was excised from the animals standing on ice and weighed after applying them on filter paper to remove excess liquid. The tissue was homogenized with 2 volumes of 63