Studies on Structure and Fanction of Staphylococcal Enterotoxin and Bacillus cereus emetic toxin

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The staphylococcal enterotoxins (SEs) are serologically classified in five types(A,B,C : C_1, C_2, C_3, D,and E). It was not yet fully understood by these studies to anaylyze the biologically and functionalyy active sites of SES.Attempts were made to investigate the antigenic determinants (epitopes) of SE-A.The results obtained were as follows.1.Native SE-A molecule contains at least 3 different antigenic determinants (synthetic peptides A-1 : amino acid residues 1-20, A-5 : 81-100 and A-8 : 141-160).2.Amino acid residue 161-180 on SE-A molecule is an essential region for production of murine INF-.To study the correlation between emetic toxin and HEp-2 vacuole activity produced by Bacillus cereus isolated from an outbreak of vomiting type food poisoning, emetic activities of purified HEp-2 factor (Cereulid) to rhesus monkeys and suncus were determined. The results obtained were as follows.1.The purified Cereulide (HEp-2 factor) is strongly suggested to be an emetic toxin itself.2.The Cereulide is stable in the digestive tracts, induce emesis, and show lethal activity leading to be cellular damage.