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 ...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.展开更多
AIM:To investigate the effect of MEK/ERK1/2 pathway on peroxisome proliferator-activated receptors(PPARγ)agonist-induced alterations in Δ6-desaturase(Δ6D)and stearoyl-CoA desaturase 1(SCD1)in hepatocellular carcino...AIM:To investigate the effect of MEK/ERK1/2 pathway on peroxisome proliferator-activated receptors(PPARγ)agonist-induced alterations in Δ6-desaturase(Δ6D)and stearoyl-CoA desaturase 1(SCD1)in hepatocellular carcinoma cell line HepG2.METHODS:HepG2 cells cultured in RPMI-1640 were exposed to the commonly used ERK1/2 pathway inhibitor PD98059 and PPARγ agonist,pioglitazone.Total RNA was isolated and reverse transcribed from treated cells.Changes in gene expression and metabolites ratio,as activity index for Δ6D and SCD1,were then determined using reverse transcriptionpolymerase chain reaction and gas liquid chromatography,respectively.RESULTS:The expression of both Δ6D(P = 0.03)and SCD1(P = 0.01)increased following PD98059 treatment,with a higher impact on SCD1(24.5%vs 62.5%).Although pioglitazone increased the mRNA level(1.47 ± 0.10 vs 0.88 ± 0.02,P = 0.006)and activity index(1.40 ± 0.07 vs 0.79 ± 0.11,P < 0.001)of Δ6D,no such changes have been observed for SCD1 activity index in pioglitazone-treated cells.SCD1 gene expression(+26.4%,P = 0.041)and activity index(+52.8%,P = 0.035)were significantly increased by MEK inhibition in the presence of pioglitazone,as compared with pioglitazone alone and control cells.However,the response of Δ6D expression and activity index to pioglitazone was unaffected by incubation with PD98059.CONCLUSION:PPARγ and ERK1/2 signaling pathway affect differentially and may have inhibitory crosstalk effects on the genes expression of 6D and SCD1,and subsequently on their enzymatic activities.展开更多
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)
文摘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.
基金Supported by A Grant from the Drug Applied Research Center of Tabriz University of Medical Sciences,to Darabi M,Research Projects numbers 89/102 and 90/73
文摘AIM:To investigate the effect of MEK/ERK1/2 pathway on peroxisome proliferator-activated receptors(PPARγ)agonist-induced alterations in Δ6-desaturase(Δ6D)and stearoyl-CoA desaturase 1(SCD1)in hepatocellular carcinoma cell line HepG2.METHODS:HepG2 cells cultured in RPMI-1640 were exposed to the commonly used ERK1/2 pathway inhibitor PD98059 and PPARγ agonist,pioglitazone.Total RNA was isolated and reverse transcribed from treated cells.Changes in gene expression and metabolites ratio,as activity index for Δ6D and SCD1,were then determined using reverse transcriptionpolymerase chain reaction and gas liquid chromatography,respectively.RESULTS:The expression of both Δ6D(P = 0.03)and SCD1(P = 0.01)increased following PD98059 treatment,with a higher impact on SCD1(24.5%vs 62.5%).Although pioglitazone increased the mRNA level(1.47 ± 0.10 vs 0.88 ± 0.02,P = 0.006)and activity index(1.40 ± 0.07 vs 0.79 ± 0.11,P < 0.001)of Δ6D,no such changes have been observed for SCD1 activity index in pioglitazone-treated cells.SCD1 gene expression(+26.4%,P = 0.041)and activity index(+52.8%,P = 0.035)were significantly increased by MEK inhibition in the presence of pioglitazone,as compared with pioglitazone alone and control cells.However,the response of Δ6D expression and activity index to pioglitazone was unaffected by incubation with PD98059.CONCLUSION:PPARγ and ERK1/2 signaling pathway affect differentially and may have inhibitory crosstalk effects on the genes expression of 6D and SCD1,and subsequently on their enzymatic activities.
