A bile‐inducible membrane protein mediates bifidobacterial bile resistance

摘要: Bbr_0838 from Bifidobacterium breve UCC2003 is predicted to encode a 683 residue membrane protein, containing both permease domain that displays similarity transporters belonging the major facilitator superfamily, as well CBS (cystathionine beta synthase) domain. The high level of bile efflux pumps other bifidobacteria suggests significant and general role for in tolerance. transcription was shown be monocistronic strongly induced upon exposure bile. Further analysis delineated transcriptional start site minimal region required promoter activity regulation. Insertional inactivation B. resulted strain, UCC2003:838(800) , which exhibited reduced survival cholate compared with parent phenotype reversed when functional, plasmid-encoded gene introduced into . Transcriptome grown presence or absence demonstrated Bbr_0832, macrolide transporter gene, significantly increased bile, representing likely compensatory mechanism removal Bbr_0838. This study represents first in-depth bile-inducible locus bifidobacteria, identifying key relevant bifidobacterial