title: Potential aquaculture probiont Lactococcus lactis TW34 produces nisin Z and inhibits the fish pathogen Lactococcus garvieae.
abstract: Bacteriocin-producing Lactococcus lactis TW34 was isolated from marine fish. TW34 bacteriocin inhibited the growth of the fish pathogen Lactococcus garvieae at 5 AU/ml (minimum inhibitory concentration), whereas the minimum bactericidal concentration was 10 AU/ml. Addition of TW34 bacteriocin to L. garvieae cultures resulted in a decrease of six orders of magnitude of viable cells counts demonstrating a bactericidal mode of action. The direct detection of the bacteriocin activity by Tricine-SDS-PAGE showed an active peptide with a molecular mass ca. 4.5 kDa. The analysis by MALDI-TOF-MS detected a strong signal at m/z 2,351.2 that corresponded to the nisin leader peptide mass without the initiating methionine, whose sequence STKDFNLDLVSVSKKDSGASPR was confirmed by MS/MS. Sequence analysis of nisin structural gene confirmed that L. lactis TW34 was a nisin Z producer. This nisin Z-producing strain with probiotic properties might be considered as an alternative in the prevention of lactococcosis, a global disease in aquaculture systems.
authors.affiliation: Centro Nacional Patagónico (CENPAT-CONICET), Blvd. Brown Nº 2915, U9120ACD, Puerto Madryn, Chubut, Argentina, sequeiro@cenpat-conicet.gob.ar.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Sequeiros
authors.forename: Marisa E
authors.initials: ME
authors.lastname: Garcés
authors.forename: Marisol
authors.initials: M
authors.lastname: Vallejo
authors.forename: Emilio R
authors.initials: ER
authors.lastname: Marguet
authors.forename: Nelda L
authors.initials: NL
authors.lastname: Olivera
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000378:metabolism / Q000494:pharmacology; D017756:Aquaculture; D004591:Electrophoresis, Polyacrylamide Gel; D005393:Fish Diseases / Q000382:microbiology* / Q000517:prevention & control*; D005399:Fishes / Q000382:microbiology; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology / Q000517:prevention & control / Q000662:veterinary*; D017045:Lactococcus / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D013294:Lactococcus lactis / Q000235:genetics / Q000502:physiology*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D009561:Nisin / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D053719:Tandem Mass Spectrometry
chemical_list: D000900:Anti-Bacterial Agents; D009561:Nisin; C071364:nisin Z