Mechanism of competence in the transformation of streptococci of serological group H

Cegłowski, Piotr; Dobrzanski, W.T.

doi:10.1007/bf00333875

Cited by 10 publications

References 18 publications

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Plasmid transformation of Streptococcus sanguis (Challis) occurs by circular and linear molecules

Behnke

1981

Molec. Gen. Genet.

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Transformation of Streptococcus sanguis (Challis) by antibiotic resistance plasmids has shown that (a) competence developed with identical kinetics for chromosomal and plasmid DNA; (b) dependence of transformant yield on plasmid DNA concentration was second order; (c) open circular plasmid DNA transformed Challis, although at reduced frequency, (d) linearization of plasmid DNA by restriction enzymes cutting at unique sites inactivated the transforming capacity; (e) transforming activity was restored when linear plasmid molecules generated by different restriction enzymes were mixed; (f) restoration of transforming activity depended on the distance between the linearizing cuts, i.e. on the presence of sufficiently long overlapping homologous sequences; (g) when linear deletion mutants were mixed with linear parental plasmids the smaller plasmid was restored with significantly higher frequency. Based on these data, a model for plasmid transformation of Challis is proposed according to which circular plasmid is linearized during binding and uptake. One DNA strand enters the cell and restoration of circular plasmids inside the cell occurs by annealing of complementary single strands from two different donor molecules. Implications of this model for recombinant DNA experiments in streptococci are discussed.

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Plasmid transformation of Streptococcus sanguis (Challis) occurs by circular and linear molecules

Behnke

1981

Molec. Gen. Genet.

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Bacterial Transformation

Venema

1979

Advances in Microbial Physiology

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Genetic Transformation in Streptococcus Sanguis

Gaustad

1979

Acta Pathologica Microbiologica Scandinavica Section B Microbio

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Forty‐one strains of Streptococcus sanguis (37 of serogroup H and four of the newly‐described serogroup W) were examined semiquantitatively for genetic transformation with streptomycin as marker. The material comprised eight reference laboratory strains and 33 recent isolates. Eighteen strains (16 of serogroup H and two of W) showed spontaneous competence in genetic transformation (without added competence factor, i.e. culture filtrate.). Individual culture filtrates from 19 spontaneously competent and ten incompetent strains were tested for competence‐inducing effect on 23 spontaneously incompetent strains. Competence was induced in 16 of the strains, and 20 of the culture filtrates were active. There was considerable variation with respect to the number of recipient strains which were induced to competence by individual filtrates. Furthermore the recipients varied as regards the number of filtrates that were able to induce that particular strain. There was some relationship, but no complete association, between competence, competence‐inducing ability and the occurrence of spreading zones around the colonies assumed to correspond generally to fimbriation. Thus, three incompetent strains had an active culture filtrate and one spontaneously competent strain had an inactive filtrate. Most, but not all, strains with spontaneous or inducible competence showed spreading, as did most of the strains from which broadly inducing filtrates could be produced.

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Mechanism of competence in the transformation of streptococci of serological group H

Cited by 10 publications

References 18 publications

Plasmid transformation of Streptococcus sanguis (Challis) occurs by circular and linear molecules

Plasmid transformation of Streptococcus sanguis (Challis) occurs by circular and linear molecules

Bacterial Transformation

Genetic Transformation in Streptococcus Sanguis

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