Dataset Information

Bioconversion From Docosahexaenoic Acid to Eicosapentaenoic Acid in the Marine Bacterium Shewanella livingstonensis Ac10.

ABSTRACT: Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which belong to the same class of long chain ?-3 polyunsaturated fatty acids (PUFAs), are present in marine ?-proteobacteria. In contrast to their de novo biosynthesis that has been intensively studied, their metabolic fates remain largely unknown. Detailed information regarding bacterial ?-3 PUFA metabolism would be beneficial for understanding the physiological roles of EPA/DHA as well as the industrial production of EPA, DHA, and other PUFAs. Our previous studies revealed that the EPA-producing marine bacterium Shewanella livingstonensis Ac10 produces EPA from exogenous DHA independently of de novo EPA biosynthesis, indicating the presence of an unidentified metabolic pathway that converts DHA into EPA. In this study, we attempted to reveal the molecular basis for the bioconversion through both in vivo and in vitro analyses. Mutagenesis experiments showed that the gene disruption of fadH, which encodes an auxiliary ?-oxidation enzyme 2,4-dienoyl-CoA reductase, impaired EPA production under DHA-supplemented conditions, and the estimated conversion rate decreased by 86% compared to that of the parent strain. We also found that the recombinant FadH had reductase activity toward the 2,4-dienoyl-CoA derivative of DHA, whereas the intermediate did not undergo ?-oxidation in the absence of the FadH protein. These results indicate that a typical ?-oxidation pathway is responsible for the conversion. Furthermore, we assessed whether DHA can act as a substitute for EPA by using an EPA-less and conversion-deficient mutant. The cold-sensitive phenotype of the mutant, which is caused by the lack of EPA, was suppressed by supplementation with EPA, whereas the DHA-supplementation suppressed it to a lesser extent. Therefore, DHA can partly substitute for, but is not biologically equivalent to, EPA in S. livingstonensis Ac10.

SUBMITTER: Ogawa T

PROVIDER: S-EPMC7264947 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Bioconversion From Docosahexaenoic Acid to Eicosapentaenoic Acid in the Marine Bacterium <i>Shewanella livingstonensis</i> Ac10.

Ogawa Takuya T Hirose Kazuki K Yusuf Yustina Y Kawamoto Jun J Kurihara Tatsuo T

Frontiers in microbiology 20200526

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which belong to the same class of long chain ω-3 polyunsaturated fatty acids (PUFAs), are present in marine γ-proteobacteria. In contrast to their <i>de novo</i> biosynthesis that has been intensively studied, their metabolic fates remain largely unknown. Detailed information regarding bacterial ω-3 PUFA metabolism would be beneficial for understanding the physiological roles of EPA/DHA as well as the industrial production of EPA, DHA, ...[more]

PMID: 32528457

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Project description:PurposeTo evaluate the associations between intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and the intermediate and advanced stages of age-related macular degeneration (AMD).DesignProspective cohort study.ParticipantsWe followed 75 889 women from the Nurses' Health Study and 38 961 men from the Health Professionals Follow-Up Study who were at least 50 years old, from 1984 to 2012 and 1986 to 2010, respectively. Cohort participants are mostly white (≥95%).MethodsWe assessed dietary intake by a validated food frequency questionnaire (FFQ) at baseline and every 4 years. We calculated cumulative average intakes of EPA and DHA from FFQs and also computed predicted erythrocyte and plasma scores directly from food intake using regression models. Cox proportional hazards models were used to compute the associations with AMD outcomes.Main outcome measuresWe confirmed 1589 incident intermediate and 1356 advanced AMD cases (primarily neovascular AMD) with a visual acuity of 20/30 or worse, owing primarily to AMD, by medical record review.ResultsFor intermediate AMD, the pooled hazard ratio (HR) between the 2 cohorts for DHA comparing the extreme quintiles of intake was 0.78 (95% confidence interval [CI], 0.66-0.92; P trend, 0.008) and for EPA + DHA was 0.83 (95% CI, 0.71-0.98; P trend, 0.03). The pooled HR for fatty fish, comparing ≥5 servings per week to almost never, was 0.61 (95% CI, 0.46-0.81; P trend, <0.001). For advanced AMD, the pooled HR for DHA was 1.01 (95% CI, 0.84-1.21; P trend, 0.75) and for fatty fish was 0.80 (95% CI, 0.59-1.08; P trend, 0.11). Secondary analyses using predicted erythrocyte and plasma scores of EPA and DHA yielded slightly stronger inverse associations for intermediate AMD and similar results for advanced AMD.ConclusionsHigher intakes of EPA and DHA may prevent or delay the occurrence of visually significant intermediate AMD. However, the totality of current evidence for EPA and DHA and advanced AMD is discordant, though there was no association with advanced AMD in the present study.

Dataset Information

Bioconversion From Docosahexaenoic Acid to Eicosapentaenoic Acid in the Marine Bacterium Shewanella livingstonensis Ac10.

Publications

Bioconversion From Docosahexaenoic Acid to Eicosapentaenoic Acid in the Marine Bacterium <i>Shewanella livingstonensis</i> Ac10.

Similar Datasets

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