title: Discovery of a conjugative megaplasmid in Bifidobacterium breve.
abstract: Bifidobacterium breve is a common and sometimes very abundant inhabitant of the human gut. Genome sequencing of B. breve JCM 7017 revealed the presence of an extrachromosomal element, designated pMP7017 consisting of >190 kb, thus representing the first reported bifidobacterial megaplasmid. In silico characterization of this element revealed several genomic features supporting a stable establishment of the megaplasmid in its host, illustrated by predicted CRISPR-Cas functions that are known to protect the host against intrusion of foreign DNA. Interestingly, pMP7017 is also predicted to encode a conjugative DNA transfer apparatus and, consistent with this notion, we demonstrate here the conjugal transfer of pMP7017 to representative strains of B. breve and B. longum subsp. longum. We also demonstrate the presence of a megaplasmid with homology to pMP7017 in three B. longum subsp. longum strains.
authors.affiliation: Alimentary Pharmabiotic Centre, National University of Ireland, Cork, Ireland.
authors.forename: Francesca
authors.initials: F
authors.lastname: Bottacini
authors.affiliation: Alimentary Pharmabiotic Centre, National University of Ireland, Cork, Ireland School of Microbiology, National University of Ireland, Cork, Ireland.
authors.forename: Mary
authors.initials: M
authors.lastname: O'Connell Motherway
authors.affiliation: School of Microbiology, National University of Ireland, Cork, Ireland.
authors.forename: Eoghan
authors.initials: E
authors.lastname: Casey
authors.affiliation: School of Microbiology, National University of Ireland, Cork, Ireland.
authors.forename: Brian
authors.initials: B
authors.lastname: McDonnell
authors.affiliation: School of Microbiology, National University of Ireland, Cork, Ireland.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Mahony
authors.affiliation: Laboratory of Probiogenomics, Department of Life Sciences, University of Parma, Parma, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Ventura
authors.affiliation: Alimentary Pharmabiotic Centre, National University of Ireland, Cork, Ireland School of Microbiology, National University of Ireland, Cork, Ireland d.vansinderen@ucc.ie.
authors.forename: Douwe
authors.initials: D
authors.lastname: van Sinderen
mesh_terms: D001644:Bifidobacterium / Q000235:genetics*; D064113:CRISPR-Cas Systems; D003227:Conjugation, Genetic; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010957:Plasmids; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial