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Salinity‐mediated regulation of DHA production in the marine bacterium Moritella marina
Author(s) -
Gillies Laura A.,
Valentine Raymond C.,
German J. Bruce
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a702
Subject(s) - salinity , docosahexaenoic acid , bacteria , food science , chemistry , biochemistry , effects of global warming on oceans , biology , fatty acid , ecology , polyunsaturated fatty acid , climate change , global warming , genetics
Docosahexaenoic acid (DHA) is important in health and development. DHA is found enriched in the membranes of neurons, sperm, rhodopsin disks, and marine bacteria. The molecular functions of DHA remain poorly understood. While studies have examined the relationship between DHA and temperature or pressure, these factors alone do not adequately explain the necessity of this lipid. We proposed that in marine bacteria DHA provides a selective advantage by altering the Na + leakage rate across the membrane. We examined the response of DHA production in the marine bacterium Moritella marina MP‐1 to varying Na + contents in the medium. Bacteria were grown in varying salt, oxygen, and temperature conditions and lipid composition, growth rates and oxidation products measured. DHA production increased with increasing salinity even at concentrations above sea water. Percent survival and lipid oxidation were measured under aerobic and anaerobic conditions with mild heat shock for 0–20 min. Results indicated that DHA production in M. marina at both 15 and 20 °C is regulated by salinity and differences in survival after mild heat shock are not oxygen dependent. These results demonstrate that DHA enriched membranes are promoted in marine bacteria providing benefits that outweigh the effects of increased oxidation.