title: Isolation and Characterization of a Broad Spectrum Bacteriocin from Bacillus amyloliquefaciens RX7.
abstract: We isolated a Bacillus strain, RX7, with inhibitory activity against Listeria monocytogenes from soil and identified it as Bacillus amyloliquefaciens based on 16S rRNA gene sequencing. The inhibitory activity was stable over a wide range of pH and was fully retained after 30 min at 80°C, after which it decreased gradually at higher temperatures. The activity was sensitive to the proteolytic action of α-chymotrypsin, proteinase-K, and trypsin, indicating its proteinaceous nature. This bacteriocin was active against a broad spectrum of bacteria and the fungus Candida albicans. Direct detection of antimicrobial activity on a sodium dodecyl sulfate-polyacrylamide gel suggested an apparent molecular mass of approximately 5 kDa. Ammonium sulfate precipitation and anion-exchange and gel permeation chromatography integrated with reverse phase-high-performance liquid chromatography were used for bacteriocin purification. Automated N-terminal Edman degradation of the purified RX7 bacteriocin recognized the first 15 amino acids as NH2-X-Ala-Trp-Tyr-Asp-Ile-Arg-Lys-Leu-Gly-Asn-Lys-Gly-Ala, where the letter X in the sequence indicates an unknown or nonstandard amino acid. Based on BLAST similarity search and multiple alignment analysis, the obtained partial sequence showed high homology with the two-peptide lantibiotic haloduracin (HalA1) from Bacillus halodurans, although at least two amino acids differed between the sequences. A time-kill study demonstrated a bactericidal mode of action of RX7 bacteriocin.
authors.affiliation: Department of Animal Resources Science, Dankook University, Cheonan 31116, Republic of Korea.
authors.forename: Kong Boon
authors.identifier: 0000-0003-3105-5533
authors.initials: KB
authors.lastname: Lim
authors.affiliation: Department of Animal Resources Science, Dankook University, Cheonan 31116, Republic of Korea.
authors.forename: Marilen P
authors.identifier: 0000-0002-3899-5125
authors.initials: MP
authors.lastname: Balolong
authors.affiliation: Department of Animal Resources Science, Dankook University, Cheonan 31116, Republic of Korea.
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Animal Resources Science, Dankook University, Cheonan 31116, Republic of Korea.
authors.forename: Ju Kyoung
authors.identifier: 0000-0002-8554-1863
authors.initials: JK
authors.lastname: Oh
authors.affiliation: National Instrumentation Center for Environmental Management, Seoul National University, Seoul 08826, Republic of Korea.
authors.forename: Ji Yoon
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Department of Animal Resources Science, Dankook University, Cheonan 31116, Republic of Korea.
authors.forename: Dae-Kyung
authors.identifier: 0000-0001-9241-1250
authors.initials: DK
authors.lastname: Kang
mesh_terms: D000890:Anti-Infective Agents / Q000302:isolation & purification* / Q000494:pharmacology*; D000069977:Bacillus amyloliquefaciens / Q000737:chemistry* / Q000235:genetics; D001430:Bacteriocins / Q000302:isolation & purification* / Q000494:pharmacology*; D002176:Candida albicans / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008089:Listeria monocytogenes / Q000187:drug effects; D008970:Molecular Weight; D059748:Proteolysis / Q000187:drug effects; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012988:Soil Microbiology; D013696:Temperature
chemical_list: D000890:Anti-Infective Agents; D001430:Bacteriocins; D012336:RNA, Ribosomal, 16S