title: Genomic and Functional Characterization of the Unusual pLOCK 0919 Plasmid Harboring the spaCBA Pili Cluster in Lactobacillus casei LOCK 0919.
abstract: Here, we report the extensive bioinformatic and functional analyses of the unusual pLOCK 0919, a plasmid originating from the probiotic Lactobacillus casei LOCK 0919 strain. This plasmid is atypical because it harbors the spaCBA-srtC gene cluster encoding SpaCBA pili. We show that all other spaCBA-srtC sequences of the Lactobacillus genus that have been previously described and deposited in GenBank are present in the chromosomal DNA. Another important observation for pLOCK 0919 is that the spaCBA-srtC gene cluster and its surrounding genes are highly similar to the respective DNA region that is present in the most well-known and active SpaCBA pili producer, the probiotic Lactobacillus rhamnosus GG strain. Our results demonstrate that the spaCBA-srtC clusters of pLOCK 0919 and L. rhamnosus GG are genealogically similar, located in DNA regions that are rich in transposase genes and are poorly conserved among the publicly available sequences of Lactobacillus sp. In contrast to chromosomally localized pilus gene clusters from L. casei and Lactobacillus paracasei, the plasmidic spaC of L. casei LOCK 0919 is expressed and undergoes a slight glucose-induced repression. Moreover, results of series of in vitro tests demonstrate that L. casei LOCK 0919 has an adhesion potential, which is largely determined by the presence of the pLOCK 0919 plasmid. In particular, the plasmid occurrence positively influenced the hydrophobicity and aggregation abilities of L. casei LOCK 0919. Moreover, in vivo studies indicate that among the three Lactobacillus strains used to colonize the gastrointestinal tract of germ-free mice, already after 2 days of colonization, L. casei LOCK 0919 became the dominant strain and persisted there for at least 48 days.
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland tamara@ibb.waw.pl.
authors.forename: Tamara
authors.initials: T
authors.lastname: Aleksandrzak-Piekarczyk
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Koryszewska-Bagińska
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Grynberg
authors.affiliation: Institute of Fermentation Technology and Microbiology, Lodz University of Technology, Lodz, Poland.
authors.forename: Adriana
authors.initials: A
authors.lastname: Nowak
authors.affiliation: Department of Pathology, The Children's Memorial Health Institute, Warsaw, Poland.
authors.forename: Bożena
authors.initials: B
authors.lastname: Cukrowska
authors.affiliation: Laboratory of Gnotobiology, Institute of Microbiology of the CAS, v. v. i., Novy Hradek, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Kozakova
authors.affiliation: Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Bardowski
mesh_terms: D000595:Amino Acid Sequence; D019881:Aminoacyltransferases / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D003546:Cysteine Endopeptidases / Q000235:genetics; D010861:Fimbriae, Bacterial / Q000235:genetics*; D016680:Genome, Bacterial; D007780:Lacticaseibacillus casei / Q000235:genetics*; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D010957:Plasmids / Q000235:genetics; D019895:Transposases / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; C104625:SpaC protein, bacteria; C509822:sortase C; D019881:Aminoacyltransferases; D019895:Transposases; D003546:Cysteine Endopeptidases
keywords: Lactobacillus; adhesion; in silico analyses; plasmid; probiotic properties; spaCBA pilus cluster