Toxicological study on the xanthid crab Zosimus aeneus in Taiwan

Toxicological study on the xanthid crab Zosimus aeneus in Taiwan

491 Abstracts Khow’ and V. Sitprija’ (‘Queen Saovabha Memorial Srinakharinwirot University, Bangkok, Thailand). Institute, and ?Department of Chem...

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491

Abstracts Khow’ and V. Sitprija’ (‘Queen Saovabha Memorial Srinakharinwirot University, Bangkok, Thailand).

Institute,

and ?Department

of Chemistry,

Faculty

of Science.

Generally, the Thai cobra (Naju knourhiu), the only subspecies in Thailand that cannot spit venom, has a monocellate hood marking (a single ring). We found 13 variations of this ‘usual’ form. We were interested in studying how hood markings might relate to venom composition. The two common variations are a standard monocellate and an irregular form. The venom of seven cobras from each of the two groups was studied by reverse-phase high-performance liquid chromatography (RP-HPLC) in order to investigate variations in protein components. The pooled fractions under the same protein peak were collected and each peak was assayed for A 2, acetylcholinesterase and direct lytic factor and for a toxicity test. The the activities of phospholipase chromatographic patterns obtained from the monocellate hood marking group and the irregular blood marking group showed no differences in protein components. However, among each group there were few differences in protein components. Phospholipase A2 activities were found in peaks VII and VIII. Acetylcholinesterase activities were seen in peaks III-VI. Peaks VI-XIII showed direct lytic activities. The most toxic peak of both groups was peak IV. From these investigations we conclude that variations in hood markings do not necessarily relate to venom protein composition.

T~~sico/ogic~~/ study* on t/z? vanthid crab Zosimus aeneus in Taiwan. D.-F. Hwang of Marine Food Science, National Taiwan Ocean University. Keelung. Taiwan,

and Y.-H. Tsai (Department R.O.C.).

Seventy-five specimens of the xanthid crab Zosinzus creneus were collected from October 1992 to November 1993 at Lanyu. Taitung Prefecture, in south-east Taiwan, and Wanlitung and Hsiaoliuchiu, Pingtung Prefecture, in south-west Taiwan. All specimens were assayed for the presence of tetrodotoxin (TTX) by the official method. The frequency value of toxic specimens was 71% and the average toxicity was 7, 3 and 8 mU,‘g in appendages, cephalothorax and viscera, respectively. It was found that the toxicity in south-west Taiwan was higher than that in south-east Taiwan. The toxicity of Z. aeneus was higher in October at Lanyu; in April at Wanlitung and Hsiaoliuchiu. The toxic specimens were extracted and partially purified by ultrafiltration and Bio-Gel P-2 column chromatography. Electrophoresis, TLC, HPLC, UV spectrum and GC-MS analyses indicated that the toxin ol Z. clmeu.7 was mainly composed of TTX and anhydrotetrodotoxin (anh-TTX), along with minor gonyautoxins (GTXs).

Cigurr/o.ricit>s qfcoinl re
of Marine

Food

More than 280 specimens of 21 species of coral reef fish were collected from adjacent waters of Taiwan during the period March 1992 to April 1994, subsequently examining the anatomical distribution of ciguatoxicity by the mouse bioassay method. The toxicity exhibited a distinct variation depending upon species, individual. tissue. region. and season of catch. Among 21 species, only the goat fish Parupenrus rrifasciam was non-toxic. Eighteen out of 21 species showed higher toxicity in the viscera than in the head and flesh. The specimens of barracuda. .S$/!~rf~~~n~~ crwlipinnis. and moray eel. Gymnorhrnz pescdoris, were more toxic during November to March. The toxlclty of the viscera in four fish, i.e. barracuda, S. ncutipinnis, moray eel, G. pe.wardori.c. parrotfish. Sum.\ gihhus, and rabbit fish, Signnus cannliculafus, was more than 3 MU/g; toxicities ;n others we;e lower than this value. The highest toxicity in the head, flesh and viscera was 2.21. 1.70 and 6.47 MU/e. resoectivelv. The toxin from barracuda, S. acu&innis, was partially purified using a silica gel column. The chemical behaviour of the toxin in the silica gel column and thin-layer chromatography of silica plates was similar to those of ciguatoxin and scaritoxin-like compounds.

.4 myoro.ric,fkction /Kim the rvnom qj’Bungarus C. E. Gwee? (Venom and Toxin Research Group, National University of Singapore, Singapore).

caeruleus. K. Alok,’ R. Yuen,’ P. Gopalakrishnakone’ and M. Departments of ‘Anatomy, ?Biochemistry, and ‘Pharmacology.

A non-lethal fraction C-VII, showing strong phospholipase A, (PLA?) activity (specific activity 326 nmoles/min/mg), was purified to homogeneity from the venom of Bun,qms caerukus by a combination of ion-exchange QAE Sephadex C-25 and CM Sephadex C-50 chromatography. C-VII is a protein of approximate mol. wt 25,000 as determined by high-performance liquid chromatoeranhv IHPLC) ael filtration and sodium dodecyl sulfate-polyacrylamide gel (SD&PAGE). It cdnstitutes 10%~of’to;al‘venom protein. It is not lethal to mice. as even a high dose of C-VII (2 mg/kg) did not kill mice, whereas the LD IOOof crude venom is 0.8 mg,‘kg. C-VII produced 100% block of indirectly evoked twitches on chick biventer cervicis muscle but it did not block the contractions caused by ACh and CCh. It did not cause any haemolysis in blood. It was found to be mildly haemorrhagic when injected intrddermally. After i.m. injection of C-VII (0.9 mg/kg) into the calf muscle of mice. light microscopy showed severe contraction of muscle fibres with delta lesion and infiltration with macrophagea, indicating severe muscle necrosis. We conclude that fraction C-VII from the venom of B. ctrmhus is a presynaptic neurotoxin with potent myotoxic effects when injected locally into the calf muscle of mice.