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Gangliosides as receptors for bacterial toxins
142
Abstracts
AUTOLYSINS OF CLOSTRIDIUM BOTULINUM TYPES A, E AND F M. Isror.a~rovstuYa, G. Srrat~osmvucova, I. Catn.gova and L. ANL4IMOVa Gamaleya Institute Academy of Medical Sciences, U.S .S .R . It was established that C. botulinum cells of different types produce autolysins . The subcellular structure were isolated from the cells after sonic treatment and subsequent differential ultracentrifugation . The cell wall fraction was used as a substrate. Simultaneously a specific enzyme was isolated from cell walls rich in sutolysin. The rate of autolysis of cell wall suspension by wall sutolysin varied, dependent on the type of botulinal microbe. Autolytic activity of type F was investigated, depending on culturee growth and growth medium. The rate sutolysis of one day growth culture was more intensive than that of 2 days. Autolytic activity decreased during sporulation . Autolysin was found to localise in cell walls and partially in cytoplasm. The sutolysin binding with the cell walls was labile ; after freeze-thawing up to SO ~ of sutolytic activity was found in the liquid phase. Divalent ions blocked lytic activity. Dithiothreitol did not affect sutolysin. We did not find any correlation between autolysin activity, lysis intensity and excretion of toxin. We failed to find any sutolytic activity during lysis and spore-forming period.
BIOLOGICAL AND IMMUNOLOGICAL STUDIES ON B. PERTUSSIS ENDOTOXIN S. S. Jant~av and B. B. GatzoxnE Haffkine Institute, Bombay, India Crude pertussis toxin was prepared by sonicating Bordetella pertussis o+~~;`ma , It was confirmed by acrylamide electrophoresis that pertussis toxin consists of 22 different fractions, of which 15 a.re anionic and 7 are cationic . Pertussis toxin was fractionated using starch block electrophoresis and each individual fraotion and crude toxin was studied for its pharmacological and immunological properties . In addition to the already reported properties such as hypoglycemia, B-adrenergic blockade, histamine sensitisation and neurological complications it also possesses a heat labile hypothermic factor which was investigated in detail . We have also tried to investigate the mechanism of action of histamine sensitisation and 13-adrenergic blockade. In our immunological studies we have observed that 2 cationic and 4 anionic fractions which were tenable to produce any pharmacological effects, were able to produce satisfactory immunological responses. The relevance of these findings will be discussed.
GANGLIOSIDES AS RECEPTORS FOR BACTERIAL TOXINS W. E. Vax Hsrrrttvoart Master of St. Cross College, University of Oxford, OXl 3TU, U.K . In 1898 WasserttKart and Taxata showed that tetanus toxin, which acts exclusively on nervous tissue, is bound by the grey matter of nervous tissue. Sixty years later it was shown that the substance in nervous tissue responsible for this binding is a ganglioside. Subsequently it was shown that there are many gangliosides. Gangliosides are amphipathic molecules consisting of water-insoluble ceramide moieties and watersoluble oligosaccharide molecules containing one sialic acid residue attached by a sialidase-stable bond and up to three others attached by sialidase-labile bonds. Tetanus has a special affinity for a particular sialidasolabile disialosylganglioside. More recently it has been shown that cholera toxin binds avidly and specifically to the sialidase-stable monosialosylganglioside known as GGnSLC, or GMI . This ganglioside, or a complex containing it, is the cell membrane receptor for cholera toxin. Gangliosides now appear to be involved in the action of several other biologically active substances, viz. E. coil toxin, staphylococcal alpha toxin, T~ibrio porahaemolyticus toxin, thyrotropic hormone, interferon, Sendai virus.
THE BIPARTITE TOXINS: EXCITING NEW DEVELOPMENTS W. E. Vart Henvnvo~v Master of St. Cross College, University of Oxford, OXl 3TU, U.K . Before a bacterial toxin or any other active macromolecule can affect a cell it must deal with the cell membrane which prevents most macromolecules from entering the cytoplasm. Some toxins, such as the cytolytic clostridial, staphylococcal and streptococcal toxins, actually destroy the membrane and their toxic
Abstracts
AUTOLYSINS OF CLOSTRIDIUM BOTULINUM TYPES A, E AND F M. Isror.a~rovstuYa, G. Srrat~osmvucova, I. Catn.gova and L. ANL4IMOVa Gamaleya Institute Academy of Medical Sciences, U.S .S .R . It was established that C. botulinum cells of different types produce autolysins . The subcellular structure were isolated from the cells after sonic treatment and subsequent differential ultracentrifugation . The cell wall fraction was used as a substrate. Simultaneously a specific enzyme was isolated from cell walls rich in sutolysin. The rate of autolysis of cell wall suspension by wall sutolysin varied, dependent on the type of botulinal microbe. Autolytic activity of type F was investigated, depending on culturee growth and growth medium. The rate sutolysis of one day growth culture was more intensive than that of 2 days. Autolytic activity decreased during sporulation . Autolysin was found to localise in cell walls and partially in cytoplasm. The sutolysin binding with the cell walls was labile ; after freeze-thawing up to SO ~ of sutolytic activity was found in the liquid phase. Divalent ions blocked lytic activity. Dithiothreitol did not affect sutolysin. We did not find any correlation between autolysin activity, lysis intensity and excretion of toxin. We failed to find any sutolytic activity during lysis and spore-forming period.
BIOLOGICAL AND IMMUNOLOGICAL STUDIES ON B. PERTUSSIS ENDOTOXIN S. S. Jant~av and B. B. GatzoxnE Haffkine Institute, Bombay, India Crude pertussis toxin was prepared by sonicating Bordetella pertussis o+~~;`ma , It was confirmed by acrylamide electrophoresis that pertussis toxin consists of 22 different fractions, of which 15 a.re anionic and 7 are cationic . Pertussis toxin was fractionated using starch block electrophoresis and each individual fraotion and crude toxin was studied for its pharmacological and immunological properties . In addition to the already reported properties such as hypoglycemia, B-adrenergic blockade, histamine sensitisation and neurological complications it also possesses a heat labile hypothermic factor which was investigated in detail . We have also tried to investigate the mechanism of action of histamine sensitisation and 13-adrenergic blockade. In our immunological studies we have observed that 2 cationic and 4 anionic fractions which were tenable to produce any pharmacological effects, were able to produce satisfactory immunological responses. The relevance of these findings will be discussed.
GANGLIOSIDES AS RECEPTORS FOR BACTERIAL TOXINS W. E. Vax Hsrrrttvoart Master of St. Cross College, University of Oxford, OXl 3TU, U.K . In 1898 WasserttKart and Taxata showed that tetanus toxin, which acts exclusively on nervous tissue, is bound by the grey matter of nervous tissue. Sixty years later it was shown that the substance in nervous tissue responsible for this binding is a ganglioside. Subsequently it was shown that there are many gangliosides. Gangliosides are amphipathic molecules consisting of water-insoluble ceramide moieties and watersoluble oligosaccharide molecules containing one sialic acid residue attached by a sialidase-stable bond and up to three others attached by sialidase-labile bonds. Tetanus has a special affinity for a particular sialidasolabile disialosylganglioside. More recently it has been shown that cholera toxin binds avidly and specifically to the sialidase-stable monosialosylganglioside known as GGnSLC, or GMI . This ganglioside, or a complex containing it, is the cell membrane receptor for cholera toxin. Gangliosides now appear to be involved in the action of several other biologically active substances, viz. E. coil toxin, staphylococcal alpha toxin, T~ibrio porahaemolyticus toxin, thyrotropic hormone, interferon, Sendai virus.
THE BIPARTITE TOXINS: EXCITING NEW DEVELOPMENTS W. E. Vart Henvnvo~v Master of St. Cross College, University of Oxford, OXl 3TU, U.K . Before a bacterial toxin or any other active macromolecule can affect a cell it must deal with the cell membrane which prevents most macromolecules from entering the cytoplasm. Some toxins, such as the cytolytic clostridial, staphylococcal and streptococcal toxins, actually destroy the membrane and their toxic