Transmission of Bacteriocinogenicity by Conjugation in Group D Streptococci

Tomura, Tsuneko; Hirano, Toyo; Ito, Takako; Yoshioka, Morimasa

doi:10.1111/j.1348-0421.1973.tb00930.x

Cited by 38 publications

(25 citation statements)

References 13 publications

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“…Such cell-to-cell contact may be mediated by a mechanism similar to that of Streptococcus faecalis (11,18,19,37); however, we have no further information indicating the precise mechanism.…”

Section: Resultsmentioning

confidence: 73%

Transfer of Plasmid-Borne Beta-Lactamase in Neisseria gonorrhoeae

Baron¹,

Saz

Kopecko³

et al. 1977

Antimicrob Agents Chemother

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Neisseria gonorrhoeae strain GC82 contains a plasmid specifying a 8-lactamase (,3-Lam+}. Mixed incubation of strain GC82 with a penicillin-susceptible (X-Lam-), streptomycin-resistant mutant of strain GC9 results in the expression of f8-lactamase activity and streptomycin resistance in the transcipients. The frequency of transfer of the plasmid-specified resistance to penicillin seems to be proportional to the initial input ratio of the mating mixture of donor to recipient and to correlate positively with bacterial density. Cell-to-cell transmission of the deoxyribonucleic acid (DNA) appears to be by a conjugal mechanism or, alternatively, by an as yet undescribed transducing phage. Additionally, whole-cell DNA from a f8-lactamase-producing strain could be used to transform streptomycin-resistant recipients, resulting in the expression of both 8-lactamase activity and streptomycin resistance in the transformants, and purified gonococcal plasmid DNA transformed Escherichia coli but not the gonococcus. Circular DNA extracted from donor GC82 comprised three molecular species (approximately 2.7, 4.8, and 25 megadaltons [Mdal]), whereas the recipients GC9-S (Ste) contained only the 2.7-Mdal cryptic DNA species. DNA from the GC9-S82 (StrW, ,8-Lam+) transcipient contained a 4.8-Mdal species in addition to the cryptic molecular species (2.7 Mdal). The finding that the transcipient will not retransfer f8-lactamase is consistent with the hypothesis that the 25-Mdal plasmid promotes mobilization of the smaller 4.8-Mdal R plasmid.Although Neisseria gonorrhoeae has been traditionally thought of as a susceptible organism, the occurrence of gonococcal strains that are relatively resistant to penicillin and other antibiotics has gradually become an important clinical problem during the past 15 years, necessitating the use of elevated dosages of penicillin. It should be noted that there have been recent indications that the minimal inhibitory concentration (MIC) for penicillin of clinical isolates has decreased somewhat (24, 31).Resistance to penicillin in bacteria is frequently associated with the presence of 18-lactamase. The literature on 83-lactamase in gramnegative bacteria has been reviewed extensively (33). A number of these resistances have been specified by R plasmids. Previously, no /8-lactamase has been reported in N. gonorrhoeae, and resistance of the gonococcus was occasioned by a change in the binding site for penicillin (34). In the last several years the isolation of /3-lactamase-producing strains ofN. gonorrhoeae has been reported (1,2,5,28,30). Recent reports have indicated the presence of plasmid-specified, /8-lactamase-containing gonococci presumably associated with very high levels of resistance in these strains (13) and conjugal transfer of the gonococcal /8-lactamase plasmid (12).Evidence for plasmid deoxyribonucleic acid (DNA) in N. gonorrhoeae strain 2686 type 1 has been presented by Engelkirk and Schoenhard (14) and Maness and Sparling (24). The presence of plasmid DNA in each of the colonial types of...

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“…Such cell-to-cell contact may be mediated by a mechanism similar to that of Streptococcus faecalis (11,18,19,37); however, we have no further information indicating the precise mechanism.…”

Section: Resultsmentioning

confidence: 73%

Transfer of Plasmid-Borne Beta-Lactamase in Neisseria gonorrhoeae

Baron¹,

Saz

Kopecko³

et al. 1977

Antimicrob Agents Chemother

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“…We began to obtain a number of these strains and found plasmids in most of them. One limiting aspect at first was the absence of an efficient approach to doing genetic studies; however, this changed dramatically with reports by Tomura et al 37 in Japan and Jacob and Hobbs 38 in the UK demonstrating conjugation. This was somewhat unexpected, due to a common belief in those days that conjugation was essentially a Gram-negative behavior (Streptomyces being the exception).…”

Section: New Territorymentioning

confidence: 88%

Tales of conjugation and sex pheromones

Clewell¹

2011

Mobile Genetic Elements

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REVIEW REVIEW use of a technique that had recently been reported by Godson and Sinsheimer 6 that utilized a detergent mixture of Brij 58 (a neutral detergent) and deoxycholate for lysis of phageinfected E. coli. During a relatively low-speed centrifugation step, the vast majority of chromosomal DNA pelleted leaving the supernatant greatly enriched in plasmid DNA. Sucrose gradient analyses of these "cleared lysates" revealed a ColE1-protein complex sedimenting slightly faster (24S) than the 23S protein-free supercoiled DNA. Surprisingly, when the 24S complex was exposed to conditions expected to affect protein structure such as proteases, strong ionic detergents or heat, the 24S complex converted to a 17S relaxed (open circular) configuration. The relaxation event involved the introduction of a strand-specific nick in the supercoiled plasmid; we therefore called the 24S entity a "relaxation complex". 7,8 The percentage of plasmid DNA that was present in the complexed state varied from less than 30%, when glucose was in the growth medium, to more than 80% when glucose was absent.

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“…Brock et al [1] and Pleceas et al [3,4] reported the percentage of typability to be 50%, 62%, and 96.2% respectively. Tomura et al [7] have also reported a high (97.5%) percentage of typability. However the latter authors considered a zone of inhibition measuring 1 mm or more as positive.…”

mentioning

confidence: 93%

“…Enterocin typing of group D streptococci has been carried out by Brock et al [1], Pleceas et al [3,4], and Tomura et al [7] on strains isolated in their countries. However no such work has been done in India.…”

mentioning

confidence: 99%

“…Based on biochemical and physiological findings [5], 116 were labeled as Streptococcus faecalis, eight as faecium and two as Streptococcus durans. All of these 130 strains (test strains) were typed by the plate assay technique of Tomura [7], with some modifications. Using a 26-gauge needle, a drop of overnight broth culture of the test strain was dropped on the surface of a serum agar plate.…”

mentioning

confidence: 99%

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