Abstract:A conjugation system initially discovered in fl-lactamase-producing gonococci mobilized small non-selftransmissible R plasmids encoding ,8-lactamase (penicillinase) production into other gonococci, Neisseria, and Escherichia coli. This conjugation system was mediated by a separate selftransmissible plasmid of 23.9 x 106 daltons, pFA2. Conjugative plasmids capable of mobilizing R plasmids were also found in nearly 8% of the non-penicillinase-producing gonococci. These were similar to pFA2 in size, buoyant densi… Show more
“…GC base agar (GCBA) plates were routinely used for cultivation of gonococci (28). Antibiotics were obtained from sources previously described (30).…”
mentioning
confidence: 99%
“…Most of this work involved a homogenic set of strains derived from FA288, a penicillinase-producing (Pcr) N. gonorrhoeae strain isolated in the United States in 1976 (11). FA288 contains three plasmids: pFAl, a cryptic 3.9-kb plasmid; pFA2, a 36-kb conjugative plasmid; and pFA3, a 7.1-kb penicillinase plasmid (30). FA293, a penicillinsensitive (Pc') derivative of FA288 which contains pFAl and pFA2 but lacks pFA3 (30), was used as a recipient in transformation.…”
mentioning
confidence: 99%
“…FA288 contains three plasmids: pFAl, a cryptic 3.9-kb plasmid; pFA2, a 36-kb conjugative plasmid; and pFA3, a 7.1-kb penicillinase plasmid (30). FA293, a penicillinsensitive (Pc') derivative of FA288 which contains pFAl and pFA2 but lacks pFA3 (30), was used as a recipient in transformation. Gonococcal Pc' plasmids were transferred to E. coli strain C600.5 (30) by transformation (8) or conjugation (30).…”
Plasmid deoxyribonucleic acid from Neisseria gonorrhoeae containing a 7.1kilobase (kb) (4.7-megadalton) penicillinase (Pcr) plasmid transformed homogenic gonococci to penicillinase production at a low frequency. About 25% of the penicillinase-producing gonococcal transformants contained Pc' plasmids which were either larger or smaller than the 7.1 kb donor plasmid; these Pcr plasmids varied in size from 3.45 to 42 kb. Some of these altered plasmids differed from the donor plasmid in stability or in frequency of mobilization by a 36-kb (24-megadalton) conjugative plasmid. A restriction endonuclease cleavage map of the 7.1kilobase Pcr plasmid and several of the smaller deleted plasmids was constructed. The most common size of altered Pc' plasmid was 5.1 kb (3.4 megadaltons). A Pc' plasmid isolated from a gonococcus in London, England, was identical with these 5.1-kb transformant plasmids in both size and restriction endonuclease cleavage profiles, suggesting that the 5.1-kb pcr plasmid could have arisen from a 7.1-kb Pcr plasmid by a transfonnation-associated deletion in nature.
“…GC base agar (GCBA) plates were routinely used for cultivation of gonococci (28). Antibiotics were obtained from sources previously described (30).…”
mentioning
confidence: 99%
“…Most of this work involved a homogenic set of strains derived from FA288, a penicillinase-producing (Pcr) N. gonorrhoeae strain isolated in the United States in 1976 (11). FA288 contains three plasmids: pFAl, a cryptic 3.9-kb plasmid; pFA2, a 36-kb conjugative plasmid; and pFA3, a 7.1-kb penicillinase plasmid (30). FA293, a penicillinsensitive (Pc') derivative of FA288 which contains pFAl and pFA2 but lacks pFA3 (30), was used as a recipient in transformation.…”
mentioning
confidence: 99%
“…FA288 contains three plasmids: pFAl, a cryptic 3.9-kb plasmid; pFA2, a 36-kb conjugative plasmid; and pFA3, a 7.1-kb penicillinase plasmid (30). FA293, a penicillinsensitive (Pc') derivative of FA288 which contains pFAl and pFA2 but lacks pFA3 (30), was used as a recipient in transformation. Gonococcal Pc' plasmids were transferred to E. coli strain C600.5 (30) by transformation (8) or conjugation (30).…”
Plasmid deoxyribonucleic acid from Neisseria gonorrhoeae containing a 7.1kilobase (kb) (4.7-megadalton) penicillinase (Pcr) plasmid transformed homogenic gonococci to penicillinase production at a low frequency. About 25% of the penicillinase-producing gonococcal transformants contained Pc' plasmids which were either larger or smaller than the 7.1 kb donor plasmid; these Pcr plasmids varied in size from 3.45 to 42 kb. Some of these altered plasmids differed from the donor plasmid in stability or in frequency of mobilization by a 36-kb (24-megadalton) conjugative plasmid. A restriction endonuclease cleavage map of the 7.1kilobase Pcr plasmid and several of the smaller deleted plasmids was constructed. The most common size of altered Pc' plasmid was 5.1 kb (3.4 megadaltons). A Pc' plasmid isolated from a gonococcus in London, England, was identical with these 5.1-kb transformant plasmids in both size and restriction endonuclease cleavage profiles, suggesting that the 5.1-kb pcr plasmid could have arisen from a 7.1-kb Pcr plasmid by a transfonnation-associated deletion in nature.
“…It is significant that a high percentage (59%) of the 160 gonococcal strains studied possessed the 24.5 Md conjugative plasmid. The presence of this transfer plasmid increases the chance of disseminating the R plasmid since it is capable of mobilizing the non-autotransmissible R plasmid into other gonococci, Neisser i a, and Escherichia coli (21). This may account for the high prevalence and steady increase of PPNG strains in Malaysia since they were first isolated in October, 1977 (14).…”
The plasmid profiles of 160 strains of Neisseria gonorrhoeae isolated in Peninsular Malaysia, comprising 80 penicillinase-producing (PPNG) and 80 nonpenicillinase-producing (non-PPNG) isolates, were determined. The 80 PPNG isolates were divided into two plasmid groups. All of them harbored two common plasmid species, a 4.4 megadalton (Md) R plasmid previously associated with p-lactamase production in PPNG strains from the Far East and a 2.6 Md multicopy plasmid of unknown function. In addition to these two plasmids, 60 (75%) PPNG isolates also carried a large 24.5 Md conjugative plasmid.In contrast, the 80 non-PPNG strains were divided into three plasmid groups. All of them possessed the 2.6 Md cryptic plasmid, and 35 (44%) isolates also harbored the 24.5 Md transfer plasmid. Besides these two plasmids, one non-PPNG isolate carried an additional 7.8 Md cryptic plasmid.
“…are constitutively competent, capable of transformation at all phases of growth (3,4). Natural transformation is the primary means of horizontal gene transfer (HGT) in Neisseria with a documented flow of information amongst both commensal and pathogenic members of the genus (5,6). Similar to the vast majority of Gram-negative bacteria, transformation in Neisseria is dependent on a type IV pilus (Tfp) complex (7).…”
The genus Neisseria contains two pathogenic species of notable public health concern: Neisseria gonorrhoeae and Neisseria meningitidis. These pathogens display a notable ability to undergo frequent programmed recombination events. The recombination mediated pathways of transformation and pilin antigenic variation in the Neisseria are well studied systems that are critical for pathogenesis. Here we will detail the conserved and unique aspects of transformation and antigenic variation in the Neisseria. Transformation will be followed from initial DNA binding through recombination into the genome with consideration to the factors necessary at each step. Additional focus is paid to the unique type IV secretion system that mediates donation of transforming DNA in the pathogenic Neisseria. The pilin antigenic variation system uses programed recombinations to alter a major surface determinant which allows immune avoidance and promotes infection. We discuss the trans-and cis-acting factors which facilitate pilin antigenic variation and present the current understanding of the mechanisms involved in the process.
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