title: Characterization of Linoleate 10-Hydratase ofLactobacillus plantarumand Novel Antifungal Metabolites.
abstract: Lactobacilli convert linoleic acid to the antifungal compound 10-hydroxy-12-octadecenoic acid (10-HOE) by linoleate 10-hydratase (10-LAH). However, the effect of this conversion on cellular membrane physiology and properties of the cell surface have not been demonstrated. Moreover,Lactobacillus plantarumproduces 13-hydroxy-9-octadecenoic acid (13-HOE) in addition to 10-HOE, but the antifungal activity of 13-HOE was unknown. Phylogenetic analyses conducted in this study did not differentiate between 10-LAH and linoleate 13-hydratase (13-LAH). Thus, linoleate hydratases (LAHs) must be characterized through their differences in their activities of linoleate conversion. Four genes encoding putative LAHs from lactobacilli were cloned, heterologous expressed, purified and identified as FAD-dependent 10-LAH. The unsaturated fatty acid substrates stimulated the growth of lactobacilli. We also investigated the role of 10-LAH in ethanol tolerance, membrane fluidity and hydrophobicity of cell surfaces in lactobacilli by disruption oflah. Compared with theL. plantarum lahdeficient strain, 10-LAH in wild-type strain did not exert effect on cell survival and membrane fluidity under ethanol stress, but influenced the cell surface hydrophobicity. Moreover, deletion of 10-LAH inL. plantarumfacilitated purification of 13-HOE and demonstration of its antifungal activity againstPenicillium roquefortiandAspergillus niger.
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton AB, Canada.
authors.forename: Yuan Y
authors.initials: YY
authors.lastname: Chen
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton AB, Canada.
authors.forename: Nuan Y
authors.initials: NY
authors.lastname: Liang
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton AB, Canada.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Curtis
authors.affiliation: Department of Agricultural, Food and Nutritional Science, University of Alberta, EdmontonAB, Canada; College of Bioengineering and Food Science, Hubei University of TechnologyWuhan, China.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Gänzle
keywords: 13-hydroxy-9-octadecenoic acid; antifungal activity; cell membrane fluidity; cell surface hydrophobicity; linoleate 10-hydratase