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Hornetin: a hornet lethal protein with phospholipase A1 activity from Vespa flavitarsus venom
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First A s i a - Pacific Congress
economic loss of animals by acute envenomation. The chronic cases, however, are even more important, as many of the toxins are either accumulated in the animal or excreted with the milk. By this food chain natural toxins or metabolites thereof may become harmful to man. We have investigated the plants Solanum
malacoxylon, Polygala klotzschii, Baccharis coridifolia, B. dracunculifolia, Thiloa glaucocarpa, Palycourea marcgravii, Pseudocalymma elegans and five species of Senecio. Isolation of the toxins has been performed by extraction and separation via different chromatographic procedures. Structure elucidation has been performed by mass spectrometry, i.r. spectroscopy and n.m.r, spectroscopy of 1H and t3C. Symptoms of poisoning by the whole plant has been correlated with the pure compounds experimentally. Post mortem examinations show that similar symptoms may be caused by chemically quite different compounds.
Study on the toxicity of blue-green algal blooms in Lake Donghu, Wuhan. Z. HE, J. He, J. Yu and M. Yu (Department of Phycology, Institute of Hydrobiology, Academia Sinica, Wuhan, Peoples Republic of China). THE TOXINSof blue-green algal blooms in the Lake Donghu region were investigated. Samples were collected in the bloom seasons (from April to November) during 1984- 1986 at regular intervals. Toxicity was tested by bioassay (mouse, intracerebral and intraperitoneal injection). The toxin was purified by extraction, ionexchange chromatography and high pressure liquid chromatography. The blooms in Lake Donghu region contained 7 species, among which 4 species were toxic, e.g. Microcystis aeruginosa, M. aeruginosa var. major, M. marginata and Anabaena flos-aquae. The toxicity and pigment composition of the blooms varied with seasons. The highest toxicity of M. aeruginosa was detected in November 1986 (LD~024.4 mg/kg mouse wt); the lowest was in August (LDs0400 mg/kg mouse wt). The purified toxin ofM. aeruginosa has u.v. absorbance at 230 and 240 nm. The toxin is a polypeptide; the main amino acids are asparatic acid, glutamic acid, alanine, serine and phenylalanine. The molecular weight is about 937. The toxin is stable to heat and an alkaline environment. It is demonstrated as a hepatotoxin. Conclusion: Microcystis aeruginosa and Anabaena flos-aquae blooms of Lake Donghu region were recognized as toxic.
Structural predictions for rattlesnake venom myotoxins. J. T. HENDERSONand A. L. BIEBER (Department of Chemistry, Arizona State University, Tempe, Arizona 85287, U.S.A.). STRUCTURALpredictions, calculated from the primary sequence data of crotamine (Crotalus durissus durissus), myotoxin a (Crotalus viridis viridis), myotoxins I and II (Crotalus viridis concolor) and peptide c (Crotalus viridis hellerO are described and the results are compared. All of the aromatic amino acids are invariant in the myotoxins studied and the lone tyrosine residue occupies the amino terminus. Predictions of secondary structural features and predictions of regions with average hydropathy values, indicating locations of antigenic sites or areas of membrane association, are of particular importance to structure-function relationships. Calculations were made using established methods. Secondary structure predictions for the myotoxins were very similar to each other. A predicted helical arrangement in the amino terminal region was consistant with data from high resolution NMR experiments on myotoxin a. Several regions were predicted as possible antigenic sites. It was therefore not surprising that production of monoclonal antibodies from several hybridoma lines was possible, even though the molecule itself is only weakly antigenic in mice. Antigenicity prediction further indicated that three of the myotoxic proteins have an antigenic determinant region which is not present in the other two. We conclude that myotoxins are likely to have similar secondary structures and predict that monoclonal antibodies can be generated that will distinguish some rattlesnake myotoxins from others. Supported by National Institutes of Health grant ROI GM34925.
Hornetin: a hornet lethal protein with phospholipase AI activity from Vespa flavitarsus venom. CHEWN-LANG HO and JAr~-LxNt~ KO (Institute of Biological Chemistry, Academia Sinica, Talpei, Taiwan, R.O.C.). WASP and hornet venoms are known to be allergic. However, deaths caused by vespid stings in humans and animals do not all result from allergic reactions. By gel filtration on a Fractogel TSK HW-50 column followed by ion-exchange chromatography on Cellulose CM-52, a lethal protein, designated as hornetin, was purified from the venom of Vespaflavitarsus. Hornetin is a highly basic protein (pI -- 10.2) with a molecular weight of about 32,000. Its amino acid composition is characterized by a high content of lysine, aspartic acid and glutamic acid, and no tryptophan or cysteine. The lack of cysteine in the molecule is distinct from other known vespid proteins. The i.v. LDsoof the toxin is 0.42/~g/g mouse. Assayed on the red blood cells of the mouse and the guinea-pig, as well as on the isolated n e r v e - muscle preparations of the chick and the mouse, hornetin showed direct hemolysis and pre-synaptic neurotoxicity at the microgram level and displayed musculotropic effects at higher concentrations. The toxin is also capable of catalyzing the hydrolysis of emulsified phosphatidylcholine, but not sphingomyelln. Its potency is about ten times that of porcine pancreatic phospholipase A2. By examining the protein magnetic resonance spectra of the phospholipid and its hydrolysed products (lyso-compound and fatty acid), it is evident that the toxin possesses a phospholipase activity of the A~ type.
First A s i a - Pacific Congress
economic loss of animals by acute envenomation. The chronic cases, however, are even more important, as many of the toxins are either accumulated in the animal or excreted with the milk. By this food chain natural toxins or metabolites thereof may become harmful to man. We have investigated the plants Solanum
malacoxylon, Polygala klotzschii, Baccharis coridifolia, B. dracunculifolia, Thiloa glaucocarpa, Palycourea marcgravii, Pseudocalymma elegans and five species of Senecio. Isolation of the toxins has been performed by extraction and separation via different chromatographic procedures. Structure elucidation has been performed by mass spectrometry, i.r. spectroscopy and n.m.r, spectroscopy of 1H and t3C. Symptoms of poisoning by the whole plant has been correlated with the pure compounds experimentally. Post mortem examinations show that similar symptoms may be caused by chemically quite different compounds.
Study on the toxicity of blue-green algal blooms in Lake Donghu, Wuhan. Z. HE, J. He, J. Yu and M. Yu (Department of Phycology, Institute of Hydrobiology, Academia Sinica, Wuhan, Peoples Republic of China). THE TOXINSof blue-green algal blooms in the Lake Donghu region were investigated. Samples were collected in the bloom seasons (from April to November) during 1984- 1986 at regular intervals. Toxicity was tested by bioassay (mouse, intracerebral and intraperitoneal injection). The toxin was purified by extraction, ionexchange chromatography and high pressure liquid chromatography. The blooms in Lake Donghu region contained 7 species, among which 4 species were toxic, e.g. Microcystis aeruginosa, M. aeruginosa var. major, M. marginata and Anabaena flos-aquae. The toxicity and pigment composition of the blooms varied with seasons. The highest toxicity of M. aeruginosa was detected in November 1986 (LD~024.4 mg/kg mouse wt); the lowest was in August (LDs0400 mg/kg mouse wt). The purified toxin ofM. aeruginosa has u.v. absorbance at 230 and 240 nm. The toxin is a polypeptide; the main amino acids are asparatic acid, glutamic acid, alanine, serine and phenylalanine. The molecular weight is about 937. The toxin is stable to heat and an alkaline environment. It is demonstrated as a hepatotoxin. Conclusion: Microcystis aeruginosa and Anabaena flos-aquae blooms of Lake Donghu region were recognized as toxic.
Structural predictions for rattlesnake venom myotoxins. J. T. HENDERSONand A. L. BIEBER (Department of Chemistry, Arizona State University, Tempe, Arizona 85287, U.S.A.). STRUCTURALpredictions, calculated from the primary sequence data of crotamine (Crotalus durissus durissus), myotoxin a (Crotalus viridis viridis), myotoxins I and II (Crotalus viridis concolor) and peptide c (Crotalus viridis hellerO are described and the results are compared. All of the aromatic amino acids are invariant in the myotoxins studied and the lone tyrosine residue occupies the amino terminus. Predictions of secondary structural features and predictions of regions with average hydropathy values, indicating locations of antigenic sites or areas of membrane association, are of particular importance to structure-function relationships. Calculations were made using established methods. Secondary structure predictions for the myotoxins were very similar to each other. A predicted helical arrangement in the amino terminal region was consistant with data from high resolution NMR experiments on myotoxin a. Several regions were predicted as possible antigenic sites. It was therefore not surprising that production of monoclonal antibodies from several hybridoma lines was possible, even though the molecule itself is only weakly antigenic in mice. Antigenicity prediction further indicated that three of the myotoxic proteins have an antigenic determinant region which is not present in the other two. We conclude that myotoxins are likely to have similar secondary structures and predict that monoclonal antibodies can be generated that will distinguish some rattlesnake myotoxins from others. Supported by National Institutes of Health grant ROI GM34925.
Hornetin: a hornet lethal protein with phospholipase AI activity from Vespa flavitarsus venom. CHEWN-LANG HO and JAr~-LxNt~ KO (Institute of Biological Chemistry, Academia Sinica, Talpei, Taiwan, R.O.C.). WASP and hornet venoms are known to be allergic. However, deaths caused by vespid stings in humans and animals do not all result from allergic reactions. By gel filtration on a Fractogel TSK HW-50 column followed by ion-exchange chromatography on Cellulose CM-52, a lethal protein, designated as hornetin, was purified from the venom of Vespaflavitarsus. Hornetin is a highly basic protein (pI -- 10.2) with a molecular weight of about 32,000. Its amino acid composition is characterized by a high content of lysine, aspartic acid and glutamic acid, and no tryptophan or cysteine. The lack of cysteine in the molecule is distinct from other known vespid proteins. The i.v. LDsoof the toxin is 0.42/~g/g mouse. Assayed on the red blood cells of the mouse and the guinea-pig, as well as on the isolated n e r v e - muscle preparations of the chick and the mouse, hornetin showed direct hemolysis and pre-synaptic neurotoxicity at the microgram level and displayed musculotropic effects at higher concentrations. The toxin is also capable of catalyzing the hydrolysis of emulsified phosphatidylcholine, but not sphingomyelln. Its potency is about ten times that of porcine pancreatic phospholipase A2. By examining the protein magnetic resonance spectra of the phospholipid and its hydrolysed products (lyso-compound and fatty acid), it is evident that the toxin possesses a phospholipase activity of the A~ type.