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Trace Elements and Polyphenol Oxidase in Clonorchis sinensis

1963; American Society of Parasitologists; Volume: 49; Issue: 2 Linguagem: Inglês

10.2307/3275983

1937-2345

Li Ma,

Parasite Biology and Host Interactions

The trace elements contents of the tissue of Clonorchis sinensis were ascertained by emission-spectroscopic and quantitative analyses. The copper content was found to be particularly high; this is attributed largely to polyphenol oxidase which is shown to be distributed in vitellaria, uterus, and eggs. The activities of this enzyme are compared with that obtained from mushroom; some difference was observed. Polyphenol oxidase present in this parasite is believed to be associated with the eggshell formation of the fluke. Tyrosine is found to be high among the free amino acids present in the fresh tissue, and the eggs give positive tests to color reaction of scleroprotein. Eggshell formation in this parasite is discussed. Clonorchis sinensis is a common parasite of man, pig, dog, cat, and rat; geographically, it is largely distributed in Southeast Asia, the South China coast, and in Japan and Korea. In heavy infections, the worm causes blocking of the biliary passage and frequently gives rise to complications, such as recurrent pyogenic cholangitis, formation of intrahepatic calculi, which may be in the form of biliary mud, associated with jaundice (Digby, 1930; Cook, Hou, Ho, and McFadzean, 1954; Stock and Tinckler, 1955; Fung, 1961; Ong, 1962). The complications are usually initiated by obstruction of the main hepatic duct or the common bile duct, aggravated by bacterial infection, such as E. coli (Hou, 1955). In an anatomical study of the liver, Hou (1956) shows that there is close relationship between primary carcinoma of the liver and infection of Clonorchis sinensis. This has been reviewed by Willis (1960) and Steiner (1959). Among the Chinese in Hong Kong, the incidence of clonorchiasis is high (Cook et al., 1954; Fung, 1961). The clinical and pathological aspects of clonorchiasis have been extensively investigated; however, the parasite-host relationship and the physiology of the worm are still inadequately studied. The biliary disturbances caused by this worm are not well understood. In the hope that a better picture may be arrived at, from the chemical viewpoint, for elucidating the effect the worm has upon its host, it is desirable to ascertain the chemical composition of the worm with the idea that this information may provide some basic explanation of its physiological activities. A survey of the parasitological literature shows that trace elements have been little investigated; the nutritional significance of these elements hardly needs to be emphasized. Attempts to determine some of the trace elements therefore were made, and the copper content in the worm tissue and in the eggs was found to be high. This has led us to examine whether this element was associated with certain enzymes, and polyphenol oxidase activities were consequently detected. Further study showed that this enzyme played an important part in eggshell formation. The following reports the results of these investigations. MATERIALS AND METHODS Assay of inorganic substances Collection of worms: Adult worms were collected from postmortem human liver specimens cut into slices which were carefully squeezed for recovery of the worms. Cutting instruments made of stainless steel were used. The worms were washed thoroughly in a Biichner funnel with 0.9% NaC1 prepared with deionized water and then briefly rinsed with water; they were allowed to drain at 4 C for at least 4 hr. These worms then were transferred to Whatman No. 42 paper to remove water and weighed for the following analyses. Preparation of ash: About 10 g of worms, collected from a single liver specimen, were dried and ashed in a platinum dish at 105 ? 5 C and 600 ? 10 C, respectively, until constant weight was attained. Two 1-ml portions of concentrated HNO3 were added before the ashing was complete. Received for publication 11 December 1962.