title: Complete sequence of low-copy-number plasmid MccC7-H22 of probiotic Escherichia coli H22 and the prevalence of mcc genes among human E. coli.
abstract: The complete sequence of the plasmid MccC7-H22 encoding microcin C7, isolated from probiotic E. coli H22, was determined and analyzed. DNA of pMccC7-H22 comprises 32,014 bp and contains 39 predicted ORFs. Two main gene clusters, i.e., genes involved in plasmid replication and maintenance and genes encoding microcin C7 synthesis, are separated by several ORFs homologous to ORFs present in IS (insertion sequence) elements and transposons. Additional 14 ORFs code for proteins with similarities to known proteins (4 ORFs) or for hypothetical proteins with unknown function (10 ORFs). The differences in G+C content of individual ORFs and gene clusters of pMccC7-H22 indicate a mosaic structure for the plasmid, resulting from recombination events. Real-time PCR quantification was applied to measure the copy number of pMccC7-H22. Escherichia coli H22 carries approximately 5 copies of pMccC7-H22 per chromosome and thus pMccC7-H22 belongs to the group of relatively low-copy-number plasmids. Following 360 generations, all bacterial colonies (out of 100 tested) synthesized microcin C7 indicating that pMccC7-H22 is stably maintained in E. coli H22. Screening of 105 E. coli strains isolated from human fecal samples revealed 2 (1.9%) strains that produced microcin C7.
authors.affiliation: Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 5, Building A6, 625 00 Brno, Czech Republic. dsmajs@med.muni.cz
authors.forename: David
authors.initials: D
authors.lastname: Smajs
authors.forename: Michal
authors.initials: M
authors.lastname: Strouhal
authors.forename: Petra
authors.initials: P
authors.lastname: Matejková
authors.forename: Darina
authors.initials: D
authors.lastname: Cejková
authors.forename: Luciana
authors.initials: L
authors.lastname: Cursino
authors.forename: Edmar
authors.initials: E
authors.lastname: Chartone-Souza
authors.forename: Jan
authors.initials: J
authors.lastname: Smarda
authors.forename: Andréa M A
authors.initials: AM
authors.lastname: Nascimento
mesh_terms: D001430:Bacteriocins / Q000235:genetics*; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics*; D019936:Probiotics; D017422:Sequence Analysis, DNA
chemical_list: D001430:Bacteriocins; C020411:microcin