title: Baker's Yeast Deficient in Storage Lipid Synthesis Uses cis-Vaccenic Acid to Reduce Unsaturated Fatty Acid Toxicity.
abstract: The role of cis-vaccenic acid (18:1n-7) in the reduction of unsaturated fatty acids toxicity was investigated in baker's yeast Saccharomyces cerevisiae. The quadruple mutant (QM, dga1Δ lro1Δ are1Δ are2Δ) deficient in enzymes responsible for triacylglycerol and steryl ester synthesis has been previously shown to be highly sensitive to exogenous unsaturated fatty acids. We have found that cis-vaccenic acid accumulated during cultivation in the QM cells but not in the corresponding wild type strain. This accumulation was accompanied by a reduction in palmitoleic acid (16:1n-7) content in the QM cells that is consistent with the proposed formation of cis-vaccenic acid by elongation of palmitoleic acid. Fatty acid analysis of individual lipid classes from the QM strain revealed that cis-vaccenic acid was highly enriched in the free fatty acid pool. Furthermore, production of cis-vaccenic acid was arrested if the mechanism of fatty acids release to the medium was activated. We also showed that exogenous cis-vaccenic acid did not affect viability of the QM strain at concentrations toxic for palmitoleic or oleic acids. Moreover, addition of cis-vaccenic acid to the growth medium provided partial protection against the lipotoxic effects of exogenous oleic acid. Transformation of palmitoleic acid to cis-vaccenic acid is thus a rescue mechanism enabling S. cerevisiae cells to survive in the absence of triacylglycerol synthesis as the major mechanism for unsaturated fatty acid detoxification.
authors.affiliation: Department of Membrane Biochemistry, Institute of Animal Biochemistry and Genetics, Slovak Academy of Sciences, Moyzesova 61, 900 28, Ivanka pri Dunaji, Slovakia.
authors.forename: Peter
authors.initials: P
authors.lastname: Sec
authors.forename: Martina
authors.initials: M
authors.lastname: Garaiova
authors.forename: Peter
authors.initials: P
authors.lastname: Gajdos
authors.forename: Milan
authors.initials: M
authors.lastname: Certik
authors.forename: Peter
authors.initials: P
authors.lastname: Griac
authors.forename: Ivan
authors.initials: I
authors.lastname: Hapala
authors.forename: Roman
authors.initials: R
authors.lastname: Holic
mesh_terms: D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology; D051048:Diacylglycerol O-Acyltransferase / Q000172:deficiency; D005229:Fatty Acids, Monounsaturated / Q000032:analysis* / Q000633:toxicity; D009154:Mutation; D009829:Oleic Acids / Q000032:analysis* / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics*; D002785:Sterol O-Acyltransferase / Q000172:deficiency; D014280:Triglycerides / Q000096:biosynthesis
chemical_list: D003470:Culture Media; D005229:Fatty Acids, Monounsaturated; D009829:Oleic Acids; D029701:Saccharomyces cerevisiae Proteins; D014280:Triglycerides; C008757:palmitoleic acid; C065593:cis-vaccenic acid; C494880:DGA1 protein, S cerevisiae; D051048:Diacylglycerol O-Acyltransferase; C543386:ARE1 protein, S cerevisiae; C543388:ARE2 protein, S cerevisiae; D002785:Sterol O-Acyltransferase