On the mechanism of conjugation in Escherichia coli K 12

Бреслер, С. Е.; Lanzov, Vladislav A.; Lukjaniec-Blinkova, A. A.

doi:10.1007/bf00433718

Cited by 39 publications

(14 citation statements)

References 30 publications

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“…pOLA52, belonging to the IncXI incompatibility group, has two recognition sites for the EcoKI system, while pHHA45, belonging to the IncN incompatibility group, does not contain any sites. Both IncXI and IncN plasmids are known to transfer in the single-stranded form (24,25,30,31).…”

Section: Methodsmentioning

confidence: 99%

“…Other experiments have shown reduced conjugational transfer between different bacterial species with diverse restriction-modification systems, indicating that they may be the cause of this reduction in transfer (21, 22), but none of these observations have been confirmed with isogenic strains by modern molecular techniques. Recent studies indicated that SauI, a type I RM system for Staphylococcus aureus, may be a barrier to transfer into and between S. aureus isolates (23), but Veiga and Phino showed that inactivation of the SauI system was not sufficient for producing strains that efficiently take up foreign DNA (6), again questioning the importance of RM systems as barriers to conjugational transfer.In the current study, we aimed to clarify the impact of a restriction-modification system in the conjugational gene transfer of single-stranded plasmidic DNA (24,25) at the genotypic level. We focused on the impact of the type I RM system EcoKI, with the recognition sequence AACN 6 GTGC, in the transfer of conjugative plasmids between RM variants of the E. coli K-12 strain MG1655.…”

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confidence: 99%

“…In the current study, we aimed to clarify the impact of a restriction-modification system in the conjugational gene transfer of single-stranded plasmidic DNA (24,25) at the genotypic level. We focused on the impact of the type I RM system EcoKI, with the recognition sequence AACN 6 GTGC, in the transfer of conjugative plasmids between RM variants of the E. coli K-12 strain MG1655.…”

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confidence: 99%

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The EcoKI Type I Restriction-Modification System in Escherichia coli Affects but Is Not an Absolute Barrier for Conjugation

Roer¹,

Aarestrup²,

Hasman³

2014

J. Bacteriol.

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The rapid evolution of bacteria is crucial to their survival and is caused by exchange, transfer, and uptake of DNA, among other things. Conjugation is one of the main mechanisms by which bacteria share their DNA, and it is thought to be controlled by varied bacterial immune systems. Contradictory results about restriction-modification systems based on phenotypic studies have been presented as reasons for a barrier to conjugation with and other means of uptake of exogenous DNA. In this study, we show that inactivation of the R.EcoKI restriction enzyme in strain Escherichia coli K-12 strain MG1655 increases the conjugational transfer of plasmid pOLA52, which carriers two EcoKI recognition sites. Interestingly, the results were not absolute, and uptake of unmethylated pOLA52 was still observed in the wild-type strain (with an intact hsdR gene) but at a reduction of 85% compared to the uptake of the mutant recipient with a disrupted hsdR gene. This leads to the conclusion that EcoKI restriction-modification affects the uptake of DNA by conjugation but is not a major barrier to plasmid transfer. The exchange of chromosomal and/or extrachromosomal DNA, such as plasmids, viruses, and transposons, is crucial for the evolution of bacteria and their ability to adapt to new environments. Exchange of genetic material occurs among both related and unrelated species of bacteria and is driven by the three horizontal gene transfer (HGT) mechanisms: conjugation, transformation, and transduction (1-3). Restriction-modification (RM) systems are described as major barriers to HGT (4-6) and comprise restriction endonucleases with a cognate methyltransferase. These recognize and cleave DNA not modified by the methyltransferase, thereby making the bacterium able to distinguish between its own (methylated) DNA and incoming nonmethylated DNA.Based on their protein-complex subunit composition and functionality, RM systems can be divided into four types; this study focuses on type I. Type I systems require products of the three genes hsdR (restriction), hsdM (methylation), and hsdS (sequence specificity) and cleave randomly at a remote distance from the recognition sequence. Restriction occurs only when a protein complex of all three gene products (R 2 M 2 S) is formed, whereas methylation of the DNA requires formation of a complex of only the HsdM and HsdS proteins (M 2 S) (7).Some studies have indicated that transfer by conjugation is unaffected by RM systems but that unmodified phage or free DNA in transformation is readily degraded (8-11). This has led to the view that the conjugational transfer of plasmids through a singlestranded DNA intermediate is immune to restriction by RM systems, as the great majority of these recognize only nonmethylated double-stranded DNA (12-17). Other studies have, however, contradicted this. In 1964, Arber and Morse (18) proposed that host specificity (RM systems) might play a role in the acceptance or rejection of DNA transferred by conjugation in Escherichia coli. In many studies from the 1960s, the t...

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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The EcoKI Type I Restriction-Modification System in Escherichia coli Affects but Is Not an Absolute Barrier for Conjugation

Roer¹,

Aarestrup²,

Hasman³

2014

J. Bacteriol.

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“…58 We know that Vaginov not only finished his novel but even managed to incorporate the editor's "ideological" comments so that the text might be published in the Soviet Union. 59 Once he had completed his work on Bambocciada, Vaginov apparently strove to become socially active as a "field specialist": in autumn 1930 he and Nikolai Chukovskii ran a literary circle at the "Svetlana" factory, and in 1932 he collaborated with other contributors to produce Four Generations, a book dedicated to the history of the workers' movement in the Narva outpost region. 60 Beginning in autumn 1932 Vaginov began to collect urban folklore and argot in his notebook, which he called "Seeds"; some of this material found its way into his final novel.…”

Section: Harpagoniana: Closing the Circlementioning

confidence: 99%

“…Inasmuch as Vaginov, not unlike Aleksandr Afinogenov, is an extremely autobiographical author, then it is valid to single out that stratum of Soviet subjectivity that Hellbeck found in the diaries of his heroes. 20 Following in Hellbeck's footsteps, we believe that we have no reason not to trust the words of the subject, that is, to distinguish between a certain objective "inner self" and an "outer mask. "…”

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confidence: 99%

The Soviet Writer Konstantin Vaginov: From Poetics to Subjectivity

Falikova

Uspenskij

2019

The Russian Review

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This article examines the prose of Konstantin Vaginov (1899–1934) through the prism of the theory of Soviet subjectivity. It analyzes four of Vaginov's novels (Goat Song, Works and Days of Svistonov, Bambocciada, and Harpagoniana) as examples of discursive praxis in the context of the creation of the “new Soviet person.” In each novel, Vaginov combines elements of both modernist and Soviet literature, but the authorial position invariably remains contradictory. This allows us to draw conclusions about the paradoxical evolution of the writer's own subjectivity, while bringing into sharp relief one of the more “successful” examples of the formation of the Soviet “I” in the late 1920s and early 1930s.

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A Redefinition of the Mating Phenomenon in Bacteria

Achtman¹,

Skurray²

1977

Microbial Interactions

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On the mechanism of conjugation in Escherichia coli K 12

Cited by 39 publications

References 30 publications

The EcoKI Type I Restriction-Modification System in Escherichia coli Affects but Is Not an Absolute Barrier for Conjugation

The EcoKI Type I Restriction-Modification System in Escherichia coli Affects but Is Not an Absolute Barrier for Conjugation

The Soviet Writer Konstantin Vaginov: From Poetics to Subjectivity

A Redefinition of the Mating Phenomenon in Bacteria

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