Low-Temperature Affected LC-PUFA Conversion and Associated Gene Transcript Level in Nannochloropsis oculata CS-179  

作　　者：MA Xiaolei ZHANG Lin ZHU Baohua PAN Kehou LI Si YANG Guanpin 

机构地区：[1]The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao 266003, P. R. China [2]College of Marine Life Sciences, Ocean University of China, Qingdao 266003, P. R. China

出　　处：《Journal of Ocean University of China》2011年第3期270-274,共5页中国海洋大学学报（英文版）

基　　金：supported by the grants from the National Key Technologies Research and Development Program of China during the Eleventh Five-Year Plan Period(No.2006BAD09A03-2);National High Technology Research and Development Program of China(863 Program)(No.2007AA09Z427);Basic Research Program of Municipal Bureau of Science and Technology of Qingdao(No.09-1-3-22-jch)

摘　　要：Nannochloropsis oculata CS-179, a marine eukaryotic unicellular microalga, is rich in long-chain polyunsaturated fatty acids (LC-PUFAs). Culture temperature affected cell growth and the composition of LC-PUFAs. At an initial cell density of 1.5 × 106 cell mL-1, the highest growth was observed at 25℃ and the cell density reached 3 × 107 cell mL-1 at the beginning of loga-rithmic phase. The content of LC-PUFAs varied with culture temperature.The highest content of LC-PUFAs (43.96%) and EPA (36.6%) was gained at 20℃. Real-time PCR showed that the abundance of Δ6-desaturase gene transcripts was significantly different among 5 culture temperatures and the highest transcript level (15℃) of Nanoc-D6D took off at cycle 21.45. The gene transcript of C20-elongase gene was higher at lower temperatures (10, 15, and 20℃), and the highest transcript level (20℃) of Nanoc-E took off at cycle 21.18. The highest conversion rate (39.3%) of Δ6-desaturase was also gained at 20℃.But the conversion rate of Nanoc-E was not detected. The higher content of LC-PUFAs was a result of higher gene transcript level and higher enzyme activity. Compared with C20-elongase gene, Δ6-desaturase gene transcript and enzyme activity varied significantly with temperature. It will be useful to study the mechanism of how the content of LC-PUFAs is affected by temperature.Nannochloropsis oculata CS-179, a marine eukaryotic unicellular microalga, is rich in long-chain polyunsaturated fatty acids （LC-PUFAs）. Culture temperature affected cell growth and the composition of LC-PUFAs. At an initial cell density of 1.5 × 106 cell mL-1, the highest growth was observed at 25℃ and the cell density reached 3 × 107 cell mL-1 at the beginning of loga-rithmic phase. The content of LC-PUFAs varied with culture temperature.The highest content of LC-PUFAs （43.96%） and EPA （36.6%） was gained at 20℃. Real-time PCR showed that the abundance of Δ6-desaturase gene transcripts was significantly different among 5 culture temperatures and the highest transcript level （15℃） of Nanoc-D6D took off at cycle 21.45. The gene transcript of C20-elongase gene was higher at lower temperatures （10, 15, and 20℃）, and the highest transcript level （20℃） of Nanoc-E took off at cycle 21.18. The highest conversion rate （39.3%） of Δ6-desaturase was also gained at 20℃. But the conversion rate of Nanoc-E was not detected. The higher content of LC-PUFAs was a result of higher gene transcript level and higher enzyme activity. Compared with C20-elongase gene, Δ6-desaturase gene transcript and enzyme activity varied significantly with temperature. It will be useful to study the mechanism of how the content of LC-PUFAs is affected by temperature.

关 键 词：Nannochloropsis oculata fatty acid Δ6-desaturase C20-elongase 

分 类 号：Q943.2[生物学—植物学] S188[农业科学—农业基础科学]