title: Characterization of reutericyclin produced by Lactobacillus reuteri LTH2584.
abstract: Lactobacillus reuteri LTH2584 exhibits antimicrobial activity that can be attributed neither to bacteriocins nor to the production of reuterin or organic acids. We have purified the active compound, named reutericyclin, to homogeneity and characterized its antimicrobial activity. Reutericyclin exhibited a broad inhibitory spectrum including Lactobacillus spp., Bacillus subtilis, B. cereus, Enterococcus faecalis, Staphylococcus aureus, and Listeria innocua. It did not affect the growth of gram-negative bacteria; however, the growth of lipopolysaccharide mutant strains of Escherichia coli was inhibited. Reutericyclin exhibited a bactericidal mode of action against Lactobacillus sanfranciscensis, Staphylococcus aureus, and B. subtilis and triggered the lysis of cells of L. sanfranciscensis in a dose-dependent manner. Germination of spores of B. subtilis was inhibited, but the spores remained unaffected under conditions that do not permit germination. The fatty acid supply of the growth media had a strong effect on reutericyclin production and its distribution between producer cells and the culture supernatant. Reutericyclin was purified from cell extracts and culture supernatant of L. reuteri LTH2584 cultures grown in mMRS by solvent extraction, gel filtration, RP-C(8) chromatography, and anion-exchange chromatography, followed by rechromatography by reversed-phase high-pressure liquid chromatography. Reutericyclin was characterized as a negatively charged, highly hydrophobic molecule with a molecular mass of 349 Da. Structural characterization (A. Höltzel, M. G. Gänzle, G. J. Nicholson, W. P. Hammes, and G. Jung, Angew. Chem. Int. Ed. 39:2766-2768, 2000) revealed that reutericyclin is a novel tetramic acid derivative. The inhibitory activity of culture supernatant of L. reuteri LTH2584 corresponded to that of purified as well as synthetic reutericyclin.
authors.affiliation: Institut für Lebensmitteltechnologie, Universität Hohenheim, D-70599 Stuttgart, Germany. michael.gaenzle@blm.tu-muenchen.de
authors.forename: M G
authors.initials: MG
authors.lastname: Gänzle
authors.forename: A
authors.initials: A
authors.lastname: Höltzel
authors.forename: J
authors.initials: J
authors.lastname: Walter
authors.forename: G
authors.initials: G
authors.lastname: Jung
authors.forename: W P
authors.initials: WP
authors.lastname: Hammes
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis* / Q000302:isolation & purification / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects; D004655:Emulsions; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000254:growth & development; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000254:growth & development; D007700:Kinetics; D007778:Lactobacillus / Q000187:drug effects / Q000502:physiology*; D008070:Lipopolysaccharides / Q000096:biosynthesis; D008826:Microbial Sensitivity Tests; D013211:Staphylococcus aureus / Q000187:drug effects; D013720:Tenuazonic Acid / Q000031:analogs & derivatives
chemical_list: D000900:Anti-Bacterial Agents; D004655:Emulsions; D005227:Fatty Acids; D008070:Lipopolysaccharides; C416127:reutericyclin; D013720:Tenuazonic Acid