title: The RND protein is involved in the vulnibactin export system in Vibrio vulnificus M2799.
abstract: Vibrio vulnificus, an opportunistic marine bacterium that causes a serious, often fatal, infection in humans, requires iron for its pathogenesis. This bacterium exports vulnibactin for iron acquisition from the environment. The mechanisms of vulnibactin biosynthesis and ferric-vulnibactin uptake systems have recently been reported, while the vulnibactin export system has not been reported. Mutant growth under low-iron concentration conditions and a bioassay of the culture supernatant indicate that the VV1_0612 protein plays a crucial role in the vulnibactin secretion as a component of the resistance-nodulation-division (RND)-type efflux system in V. vulnificus M2799. To identify which RND protein(s) together with VV1_0612 TolC constituted the RND efflux system for vulnibactin secretion, deletion mutants of 11 RND protein-encoding genes were constructed. The growth inhibition of a multiple mutant (Δ11) of the RND protein-encoding genes was observed 6 h after the beginning of the culture. Furthermore, ΔVV1_1681 exhibited a growth curve that was similar to that of Δ11, while the multiple mutant except ΔVV1_1681 showed the same growth as the wild-type strain. These results indicate that the VV1_1681 protein is involved in the vulnibactin export system of V. vulnificus M2799. This is the first genetic evidence that vulnibactin is secreted through the RND-type efflux systems in V. vulnificus.
authors.affiliation: Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kawano
authors.affiliation: Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
authors.forename: Katsushiro
authors.initials: K
authors.lastname: Miyamoto
authors.affiliation: Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Yasunobe
authors.affiliation: Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Murata
authors.affiliation: Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
authors.forename: Tomoka
authors.initials: T
authors.lastname: Myojin
authors.affiliation: Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tsuchiya
authors.affiliation: Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, 4-2 Bunkyo-cho, Matsuyama, Ehime 790-8578, Japan.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Tanabe
authors.affiliation: Laboratory of Hygienic Chemistry, College of Pharmaceutical Sciences, Matsuyama University, 4-2 Bunkyo-cho, Matsuyama, Ehime 790-8578, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Funahashi
authors.affiliation: Department of Analytical Chemistry, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
authors.forename: Takaji
authors.initials: T
authors.lastname: Sato
authors.affiliation: Department of Analytical Chemistry, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Azuma
authors.affiliation: Department of Analytical Chemistry, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Mino
authors.affiliation: Department of Microbiology, Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan. Electronic address: tsujibo@gly.oups.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsujibo
mesh_terms: D000577:Amides / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry; D004252:DNA Mutational Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D017353:Gene Deletion; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010080:Oxazoles / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D041261:Vibrio vulnificus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D000577:Amides; D003470:Culture Media; D004269:DNA, Bacterial; D026901:Membrane Transport Proteins; D010080:Oxazoles; C086667:vulnibactin
keywords: RND-type efflux system; Vibrio vulnificus; Vulnibactin secretion