Publications

• Isolation and characterization of genes from the marine microalga Pavlova salina encoding three front-end desaturases involved in docosahexaenoic acid biosynthesis.

  Zhou X.R., Robert S.S., Petrie J.R., Frampton D.M., Mansour M.P., Blackburn S.I., Nichols P.D., Green A.G., Singh S.P.

  The marine microalga Pavlova salina produces lipids containing approximately 50% omega-3 long chain polyunsaturated fatty acids (LC-PUFA) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Three cDNA sequences, designated PsD4Des, PsD5Des, PsD8Des, were isolated from P. salina and ... >> More

  The marine microalga Pavlova salina produces lipids containing approximately 50% omega-3 long chain polyunsaturated fatty acids (LC-PUFA) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Three cDNA sequences, designated PsD4Des, PsD5Des, PsD8Des, were isolated from P. salina and shown to encode three front-end desaturases with Delta4, Delta5 and Delta8 specificity, respectively. Southern analysis indicated that the P. salina genome contained single copies of all three front-end fatty acid desaturase genes. When grown at three different temperatures, analysis of fatty acid profiles indicated P. salina desaturation conversions occurred with greater than 95% efficiency. Real-Time PCR revealed that expression of PsD8Des was higher than for the other two genes under normal growth conditions, while PsD5Des had the lowest expression level. The deduced amino acid sequences from all three genes contained three conserved histidine boxes and a cytochrome b(5) domain. Sequence alignment showed that the three genes were homologous to corresponding desaturases from other microalgae and fungi. The predicted activities of these three front-end desaturases leading to the synthesis of LC-PUFA were also confirmed in yeast and in higher plants. << Less

  Phytochemistry 68:785-796(2007) [PubMed] [EuropePMC]

  This publication is cited by 7 other entries.

• The Delta8-desaturase of Euglena gracilis: an alternate pathway for synthesis of 20-carbon polyunsaturated fatty acids.

  Wallis J.G., Browse J.

  Desaturation of fatty acids is an important metabolic process. In mammals, 20-carbon and longer polyunsaturated fatty acids are not only incorporated into cellular membranes in a tissue-specific manner, but also serve as the precursors to synthesis of eicosanoid metabolic regulators. The processes ... >> More

  Desaturation of fatty acids is an important metabolic process. In mammals, 20-carbon and longer polyunsaturated fatty acids are not only incorporated into cellular membranes in a tissue-specific manner, but also serve as the precursors to synthesis of eicosanoid metabolic regulators. The processes of desaturation and elongation in human liver are well characterized, but an alternate Delta8 desaturation pathway that may be important in certain tissues or in cancer cells is less well examined. The Delta8-desaturase enzyme introduces a double bond at the 8-position in 20-carbon fatty acids that have an existing Delta11 unsaturation. We have isolated the first fatty acid Delta8-desaturase, from the protist Euglena gracilis, in order to explore this alternate pathway. A full-length cDNA was obtained after reverse transcription of mRNA purified from heterotrophically grown Euglena, followed by PCR amplification with primers degenerate to conserved histidine-rich regions of microsomal desaturases. The protein predicted from the cDNA sequence is highly homologous to Delta5 and Delta6 desaturases of Caenhorabditis elegans. When the cDNA was expressed in Saccharomyces cerevisiae, the yeast cultures readily desaturated appropriate 20-carbon fatty acids by inserting an additional double bond at the Delta8-position. The enzyme demonstrated a preference for substrates of metabolic significance, 20:3 Delta11,14,17 and 20:2 Delta11,14. Cloning of a Delta8 fatty acid desaturase offers the opportunity to examine an alternate pathway of long chain fatty acid biosynthesis. << Less

  Arch. Biochem. Biophys. 365:307-316(1999) [PubMed] [EuropePMC]

  This publication is cited by 9 other entries.