| conjugative plasmids in neisseria gonorrhoeae. | a conjugation system initially discovered in beta-lactamase-producing gonococci mobilized small non-selftransmissible r plasmids encoding beta-lactamase (penicillinase) production into other gonococci, neisseria, and escherichia coli. this conjugation system was mediated by a separate selftransmissible plasmid of 23.9 x 10(6) 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 i ... | 1978 | 418060 |
| identification and characterization of a new replication region in the neisseria gonorrhoeae beta-lactamase plasmid pfa3. | the 7.1-kilobase-pair (kbp) plasmid pfa3 specifies tem beta-lactamase production in neisseria gonorrhoeae. we studied the minimal region required for replication of this plasmid in escherichia coli by constructing a set of nested deletions of the 3.4-kbp psti-hindiii fragment. the smallest fragment capable of maintenance in e. coli when ligated to a streptomycin-spectinomycin resistance cassette was 2.0 kbp in size and was different from another autonomously replicating fragment of pfa3 reported ... | 1990 | 2110142 |
| nucleotide sequence comparisons of plasmids phd131, pjb1, pfa3, and pfa7 and beta-lactamase expression in escherichia coli, haemophilus influenzae, and neisseria gonorrhoeae. | the sites of initiation for beta-lactamase mrna transcription and the nucleotide sequences of beta-lactamase plasmids derived from haemophilus and neisseria species were determined. in n. gonorrhoeae, transcription from plasmid pfa3 was initiated from two sites, one located about 20 base pairs (bp) and the other 210 bp upstream of the beta-lactamase initiating codon, whereas in h. influenzae, transcriptional initiation from plasmid phd131 occurred at two different sites, approximately 150 and 17 ... | 1987 | 2439488 |
| the construction and characterization of neisseria gonorrhoeae lacking protein iii in its outer membrane. | protein iii (piii) is a highly conserved, antigenically stable gonococcal outer membrane protein that is closely associated with the major outer membrane protein, protein i (pi). we have previously reported the cloning of the piii gene. this gene was inserted into the eco ri site of the runaway plasmid pmob45. the beta-lactamase (beta la) bam hi restriction fragment from the gonococcal plasmid pfa3 was inserted at the xba i site in the piii gene. the plasmid construct was hae iii methylated and ... | 1989 | 2499656 |
| construction of isogenic gonococcal strains varying in the presence of a 4.2-kilobase cryptic plasmid. | a 4.2-kilobase (kb) cryptic plasmid is present in 96% of isolates of neisseria gonorrhoeae. an inability to construct isogenic derivatives which vary in the presence of the 4.2-kb plasmid has prevented the study of its function. we report a method to deliver an intact 4.2-kb plasmid into plasmidless gonococcal strains. the method involved transformation with novel 15.7-kb hybrid penicillinase-producing (pcr) plasmids, which were cointegrates containing two copies of the 4.2-kb plasmid arranged i ... | 1986 | 3090021 |
| marker rescue by a homologous recipient plasmid during transformation of gonococci by a hybrid pcr plasmid. | a 42-kilobase hybrid pcr plasmid (pfa14) was formed when the naturally occurring 7.2-kilobase pcr plasmid pfa3 was introduced by transformation into a competent gonococcal recipient containing the 36-kilobase conjugative plasmid pfa2 (sox et al., j. bacteriol. 138:510-518). analysis of the structure of pfa14 showed that it was a stable recombinant between pfa3 and pfa2. the transformation efficiency of pfa14 was increased 300- to 10,000-fold by the presence in isogenic recipients of the homologo ... | 1982 | 6282813 |
| deletion and transposon mutagenesis and sequence analysis of the pro1600 orir region found in the broad-host-range plasmids of the pqf series. | the nucleotide sequence of the replicative origin (orir) region of the small cryptic broad-host-range plasmid, pro1600, which forms the basis of a number of useful cloning vectors has been determined. in addition it has been subjected to tn5 mutagenesis, deletion analysis, and subcloning in order to define the regions essential for replication in pseudomonas aeruginosa. the sequence (1894 bp) contains a fragment derived from transposon tn1. the orir region is structurally related to other replic ... | 1994 | 8058819 |