The mechanism of competence in the transformation ofStreptococci of serological group H

Osowiecki, H; Nalecz, J.; Dobrzanski, W.T.

doi:10.1007/bf00750310

Cited by 15 publications

(10 citation statements)

References 5 publications

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“…There is also evidence that donor strains of Escherichia colh produce "recombination stimulating factors" (18) which affect recipients. Transformable streptococci produce competence factors, extracellular proteins required for transformation (19,20). Many fungal sex hormones have been described (for a review see ref.…”

Section: Discussionmentioning

confidence: 99%

Induced cell aggregation and mating in Streptococcus faecalis: evidence for a bacterial sex pheromone.

Dunny¹,

Brown²,

Clewell³

1978

Proc. Natl. Acad. Sci. U.S.A.

507

335

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Recipient strains of Streptococcus faecalis produce a trypsin sensitive, heat resistant, nuclease resistant factor, designated clumping-inducing agent (CIA) which causes strains carrying certain conjugative plasmids to aggregate. RNA and protein synthesis but not DNA synthesis are required for aggregation to occur. Recipient filtrates that contain CIA activity also induce donors to mate at high frequencies. Introduction of a transferable plasmid into strains producing CIA dramatically reduces the amount of CIA activity produced by the strain but allows the strain to respond to exogenously added CIA. Our data suggest that CIA represents a bacterial sex hormone (pheromone).

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Section: Discussionmentioning

confidence: 99%

Induced cell aggregation and mating in Streptococcus faecalis: evidence for a bacterial sex pheromone.

Dunny¹,

Brown²,

Clewell³

1978

Proc. Natl. Acad. Sci. U.S.A.

507

335

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“…The activity of cpf was determined in biological units as described previously (Osowiecki et al, 1969) by measuring the degree of competence induction in S. wicky.…”

Section: Methodsmentioning

confidence: 99%

“…It was found, in studies on purification of S. challis cpf, that some partly purified cpf preparations contained a factor inactivating transforming DNA in vitro (Osowiecki et al, 1969). Preliminary data on the factor and on its relationship to competence in group H Streptococci have been published elsewhere (Nat¢cz et al, 1970).…”

mentioning

confidence: 99%

Correlation between the occurrence of competence in the transformation of group HStreptococci and the presence of the competence factor and thein vitro DNA-inactivating factor

Nalecz¹,

Dobrzanski²

1972

Molec. Gen. Genet.

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In experiments with strains of group H streptococci (S. challis, S. wicky, S. blackburn, S. channon, and S. wicky transformants producing the competence factor) new observations were made suggesting that the occurrence of competence is associated not only with the presence of the competence factor (epf) but also with the in vitro DNA-inactivating group H streptococcal factor (iF) which was previously described by us.The iF preparations--cell surface extracts--were shown to contain nuclease, most likely DNase. The iF activity increased after short heating at 90 °. Further evidence was presented that cpf and iF are separate activities. The non-transformable strains S. blackburn and S. channon were found to produce cpf.Proteolytic enzymes, when added to the culture several minutes prior to, or at the competence peak, were found to increase markedly the transformation yield, at the same time making it impossible to detect cpf in the cell extracts. This observation may suggest that the presence of cpf in cell layers accessible to the enzymes is not necessary in the period when DNA is taken up, although epf has to be produced previously by the recipient or has to be in contact with it. Enzyme addition did not influence the iF activity in vivo.In crude iF preparations a factor was detected which inactivates cpf in vitro. Some aspects of the competence mechanism are discussed.

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“…. 67 Bacillus subtilis is the most desirable organism for transformation studies because: (1) it is avirulent, (2) it can be grown in a simple, chemically defined medium, and (3) numerous auxotrophic mutants can be isolated,…”

Section: List Of Tablesmentioning

confidence: 99%

The effect of osmotic shocking upon Bacillus subtilis transformation

Pierson¹,

Weppner²,

Leach³

1972

Can. J. Microbiol.

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Osmotic shocking of competent Bacillus subtilis reduced transformability by 80–90% through depressing the uptake of radioactive DNA. The supernatant solution from competent cultures restored both transformation and DNA uptake. A factor, which was inactivated by proteolytic enzymes and which was released into the supernatant solution concomitant with the development of maximum competence, was responsible for restoration of transformability. This factor was both heat and pH labile and was produced only by competent strains. While the shock fluid did not restore transformability to shocked ceils, it increased competence 20-fold in a low-transforming strain. The supernatant solution from competent cultures also increased transformability of the low-competence strain. Thus it appears that at least two factors are involved in competence restoration.

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The mechanism of competence in the transformation ofStreptococci of serological group H

Cited by 15 publications

References 5 publications

Induced cell aggregation and mating in Streptococcus faecalis: evidence for a bacterial sex pheromone.

Induced cell aggregation and mating in Streptococcus faecalis: evidence for a bacterial sex pheromone.

Correlation between the occurrence of competence in the transformation of group HStreptococci and the presence of the competence factor and thein vitro DNA-inactivating factor

The effect of osmotic shocking upon Bacillus subtilis transformation

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