The tissue distribution of Rhodanese in different species of the genus Barbus (B. sharpeyi, B. grypus, B. xanthopterus and B. Barbulus)

Free cyanide is a potent toxic agent in the aquatic environments. Freshwater fishesare the most cyanide-sensitive group with high mortality at free cyanideconcentrations above 20 2 μ g/L. exposure to cyanide ions can cause stress, increase inmortality and place an appreciable metabolic load on fishes. Rhodanese is aubiquitous mitochondrial enzyme in both prokaryotes and eukaryotes that detoxifiesUcyanideU (CNP - ) by converting it to Tthiocyanate (SCN- ). The purpose of this study wasto determine and compare the pattern of tissue distribution of Rhodanese in differenttissues of four native Barbus fish including B. sharpeyi, B. grypus, B. xanthopterusand B. barbulus. Fishes (6 from each species) with length of 32.5 ± 6.5 and weightof 440 ± 110 were collected from five stations in Karun River including Gotvand,Shushtar, Molasani, Darkhoine and Ahvaz. Rhodanese was assayed by the method ofAgboola and Okonji in the liver, kidney, gill and intestine. The unit of enzymeactivity was defined as micromoles thiocyanate formed per minute at 37°C and pH9.2 and enzyme activity expressed as U/mg protein. Rhodanese activity was detectedin all tissues, albeit in different amounts. Specific activities of rhodanese (U/mgprotein) were ranged from 0.094 to 0.337 in different tissues. The highest activity ofRhodanese in all four species were observed in the liver and kidney, followed by thegill and intestine. With respect to decreasing the water flow and increasing thepollutant levels in the Karun River it is possible to determine the severity of cyanidecontamination of water or fishes by determination of Rhodanese activity in differenttissues of fishes.

کلیدواژه ها:

Rhodanese ، Free cyanide ، Tissue distribution ، Native Barbus fishes ، Karun River