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THE GENETIC CONTROL OF VIRULENCE IN GROUP A STREPTOCOCCI
Author(s) -
BUROVA LARISSA A.,
RAVDONIKAS LARISSA E.,
CHRISTENSEN POUL,
SCHALÉN CLAËS,
TOTOLIAN ARTEM A.
Publication year - 1983
Publication title -
acta pathologica microbiologica scandinavica series b: microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0108-0180
DOI - 10.1111/j.1699-0463.1983.tb00010.x
Subject(s) - extrachromosomal dna , plasmid , microbiology and biotechnology , biology , virulence , receptor , dna , genetics , gene
The erythromycin‐resistance marker of two plasmids, pSM19035 and pERL1, could be transferred by conjugation in matings within group A streptococci and between group H and group A streptococci, with a frequency of 10 ‐5 to 8 times 10 ‐7 . Two of the recipient strains used, 22v‐1 and 22v‐2, showed traces of opacity factor (OF) activity. This activity increased markedly upon transfer of both plasmids to the strains, whereas a number of other recipients, viz. 22h‐21, 12Teiko‐1 and Challis 6–1, remained OF‐negative after conjugation. Furthermore, the transconjugants resulting from matings using strains 22v‐1 and 22v‐2 as recipients expressed anti‐phagocytic activity. Attempts were made to type the transconjugants but they did not belong to type M12, M22 (the types from which the parents were derived) M3 or M1. Concomitant with the expression of anti‐phagocytic activity, IgG and IgA Fc‐receptor activity occurred in the transconjugants of 22v‐1 and 22v‐2, whereas the donor and recipient cells were without receptors. It was not possible to demonstrate extrachromosomal DNA in transconjugants possessing anti‐phagocytic, OF or Fc‐receptor activity, although they retained their ability to serve as donors of the Em r marker. It is suggested that the triggering by plasmids of antiphagocytic activity, OF and IgG and IgA Fc‐receptors is due to insertion of plasmid DNA into the chromosome.