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The biosynthesis of aflatoxins and its control
Abstracts
143
activity is in fact this destruction of the membrane . But several toxins act without any apparent destructive effect, on the inner side of the cell membrane. They have a means of penetrating the cell membrane which results from their being bipartite, that is, consisting of two separable parts, A (for active) and B (for binding). These parts may be held together by noa~ovalent bonds or by easily cleavable covalent bonds, viz. peptide bonds that are `nicked' by professes and sulphydryl bonds that are cleaved by reducing agents. The B components, are inert, but bind to specific receptors on the cell membrane, and in so going facilitate the transport of the active A component through the membrane . The bipartite active macromolecules that will be discussed are diphtheria toxin, cholera toxin, ricin, abrin, possibly tetanus and botulinum toxins, and thyrotropic hormone.
PLANTS INVESTIGATIONS ON SOME TOXIC CONSTITUENTS OF INDIAN PLANTS T. R. GOVII~ACHARI, B. S. Josfn and N. V~tweruzx uv Natural Products Division, CIBA-GEIGY Research Centre, Goregaon, Bombay 400 063, India During the routine screening of plants for biological activity, several toxic constituents have been encountered. The chemical and biological investigations on somo of these compounds will be presented. The studies pertain to the following plants : Cleistanthus collines, S~meearpus anacardium, Mappia joeNda, Ochrocarpes lortgjjolius and Lasiosiphoe eriocephalus . INVESTIGATION OF LEUKOCYTOSIS AND DEGENERATION OF SKELETAL MUSCLES INDUCED BY PLANT TOXINS
R. R Iüo Toxicology and Pathology Department, CIBA-GEIGY Research Centre, Goregaon, Bombay 400 063, India Cleistanthin, a new glycoside from Cleistanthus collines (Ro-sb.) a plant employed as a fish poison, induced significant increave in neutrophilic granulocytes (NG) when a single dose was administered either orally or parenterally to normal rats, mice, cats and monkeys. Prophylactic and curative effect of Cleistanthin on leukope~nia, induced in rats with cyclophosphamide and benzeno was evaluated. Details of these experiments as well as toxicological investigations will be presented. Widespread skeletal muscle degeneration associated with a disease syndrome characterized by an afebrile course, dark red urine, ataxia, recumbency and death was observed in animals fed on leaves and pods of Cassia occidentalis plant. Pathological investigations on the affected animals will be presented. THE BIOSYNTHESIS OF AFLATOXINS AND TTS CONTROL T. A. VsrtxiTesvsn~ruaes and K. K. NL~c~ox Department of Biochemistry, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi-110 007, India With a view to control the formation of afiatozins in agricultural commodities, the biosynthesis of aflatoxins have been studied. A synthetic medium was developed in our laboratory giving good afiatoxin yields . Using this medium, various factors such as substitution of ammonium sulphate by various nitrogen sources and substituting the sucrose by different carbon sources and carboxylic acid on equivalent carbon basis were studied. The trace metals play a very significant role in aflatozin biosynthesis. The effect of various trace metals (zinc, barium, cadmium, vanadium and copper) were investigated. The role of zinc phytic acid is aflatoxin-resistance of soyabean, stimulatory action of zinc on afiatoxin formation and primary metabolism of Aspergillus parasiticus and a comparative study of afiatoxigenic and non-aflatoxigenic strains have been carried out. The influence of TCA cycle intermediates on acetate incorporation into aflatoxin and the effect of mercaptoethanol has also been investigated . The comparative blochemistry of the toxigcnic strain and the aoa-toxigenic strain have been carried out with respoct to fat, protein, carbohydrate and nucleotide content. Some of the enzymes of the glycolytic activity and TCAcycle is the two strains have also been investigated .
143
activity is in fact this destruction of the membrane . But several toxins act without any apparent destructive effect, on the inner side of the cell membrane. They have a means of penetrating the cell membrane which results from their being bipartite, that is, consisting of two separable parts, A (for active) and B (for binding). These parts may be held together by noa~ovalent bonds or by easily cleavable covalent bonds, viz. peptide bonds that are `nicked' by professes and sulphydryl bonds that are cleaved by reducing agents. The B components, are inert, but bind to specific receptors on the cell membrane, and in so going facilitate the transport of the active A component through the membrane . The bipartite active macromolecules that will be discussed are diphtheria toxin, cholera toxin, ricin, abrin, possibly tetanus and botulinum toxins, and thyrotropic hormone.
PLANTS INVESTIGATIONS ON SOME TOXIC CONSTITUENTS OF INDIAN PLANTS T. R. GOVII~ACHARI, B. S. Josfn and N. V~tweruzx uv Natural Products Division, CIBA-GEIGY Research Centre, Goregaon, Bombay 400 063, India During the routine screening of plants for biological activity, several toxic constituents have been encountered. The chemical and biological investigations on somo of these compounds will be presented. The studies pertain to the following plants : Cleistanthus collines, S~meearpus anacardium, Mappia joeNda, Ochrocarpes lortgjjolius and Lasiosiphoe eriocephalus . INVESTIGATION OF LEUKOCYTOSIS AND DEGENERATION OF SKELETAL MUSCLES INDUCED BY PLANT TOXINS
R. R Iüo Toxicology and Pathology Department, CIBA-GEIGY Research Centre, Goregaon, Bombay 400 063, India Cleistanthin, a new glycoside from Cleistanthus collines (Ro-sb.) a plant employed as a fish poison, induced significant increave in neutrophilic granulocytes (NG) when a single dose was administered either orally or parenterally to normal rats, mice, cats and monkeys. Prophylactic and curative effect of Cleistanthin on leukope~nia, induced in rats with cyclophosphamide and benzeno was evaluated. Details of these experiments as well as toxicological investigations will be presented. Widespread skeletal muscle degeneration associated with a disease syndrome characterized by an afebrile course, dark red urine, ataxia, recumbency and death was observed in animals fed on leaves and pods of Cassia occidentalis plant. Pathological investigations on the affected animals will be presented. THE BIOSYNTHESIS OF AFLATOXINS AND TTS CONTROL T. A. VsrtxiTesvsn~ruaes and K. K. NL~c~ox Department of Biochemistry, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi-110 007, India With a view to control the formation of afiatozins in agricultural commodities, the biosynthesis of aflatoxins have been studied. A synthetic medium was developed in our laboratory giving good afiatoxin yields . Using this medium, various factors such as substitution of ammonium sulphate by various nitrogen sources and substituting the sucrose by different carbon sources and carboxylic acid on equivalent carbon basis were studied. The trace metals play a very significant role in aflatozin biosynthesis. The effect of various trace metals (zinc, barium, cadmium, vanadium and copper) were investigated. The role of zinc phytic acid is aflatoxin-resistance of soyabean, stimulatory action of zinc on afiatoxin formation and primary metabolism of Aspergillus parasiticus and a comparative study of afiatoxigenic and non-aflatoxigenic strains have been carried out. The influence of TCA cycle intermediates on acetate incorporation into aflatoxin and the effect of mercaptoethanol has also been investigated . The comparative blochemistry of the toxigcnic strain and the aoa-toxigenic strain have been carried out with respoct to fat, protein, carbohydrate and nucleotide content. Some of the enzymes of the glycolytic activity and TCAcycle is the two strains have also been investigated .