Beef from Japanese Black cattle (JBK), is popular in Japan and valued for its highly marbled fat content. In JBK, genes affecting oleic acid content in meat have been studied mainly to lower the fat melting point and ...Beef from Japanese Black cattle (JBK), is popular in Japan and valued for its highly marbled fat content. In JBK, genes affecting oleic acid content in meat have been studied mainly to lower the fat melting point and improve tenderness;however, there has been no direct correlation demonstrated between beef taste and oleic acid. To investigate genes affecting other fatty acids other than oleic acid, polymorphisms of the fatty acid desaturase 2 (FADS2) gene were genotyped and associations with fatty acid profile in JBK beef were investigated. Amplifications of 5’-flanking regions, 12 exons, and 3’-untranslated regions of the FADS2 gene in three Japanese and five Western cattle breeds via PCR, were amplified, sequenced and SNPs were identified using specific TaqMan genotyping assay. Fatty acid composition of intramuscular adipose tissue of the Trapezius muscle was analyzed in JBK steers. Six of the 15 identified SNPs are novel and have never been registered in any public bovine SNP database. A non-synonymous SNP (rs211580559;C > T;294 Ala > Val) in exon 7 was examined in order to evaluate its association with fatty acid profiles. The data showed that highly significant association existed between rs211580559 and C18:2 (n-6) composition, and accounted for 22.3% of the variation. There were no significant relationships between rs2115-80559 and the other fatty acids. It was concluded that rs211580559 of the FADS2 gene may be a useful selection marker for reducing unfavorable volatiles generated from linoleic acid in JBK beef during the cooking process.展开更多
Background：Fatty acid（FA） composition is the most important parameter affecting the flavor and nutritional value of the meat.The final and the only committed step in the biosynthesis of triglycerides is catalyzed b...Background：Fatty acid（FA） composition is the most important parameter affecting the flavor and nutritional value of the meat.The final and the only committed step in the biosynthesis of triglycerides is catalyzed by diacylglycerol acyltransferase 2（DGAT2）.The role of DGAT2 in lipid accumulation has been demonstrated in adipocytes,However,little is known about the effect of DGAT2 on the FA composition of these cells.Methods：To investigate the role of DGAT2 in regulating lipid accumulation,FA composition and the expression of adipogenic genes,we cloned the open reading frame of the porcine DGAT2 gene and established 3T3-L1 cells that overexpressed DGAT2.Cells were then cultured in differentiation medium（DM） without FA,with a mixture of FAs（FA-DM）,or containing a ^（13）C stable isotope-labeled FA mixture（IFA-DM）.The FA composition of adipocytes was analyzed by gas chromatography-mass spectrometry and gas chromatography-isotope ratio mass spectrometry.Quantitative PCR and western blotting were employed to detect expression of adipogenic genes in 3T3-L1 adipocytes cultured with FA-DM for 12 d.Results：The triacylglyceride（TAG） content was significantly higher in 3T3-L1 adipocytes overexpressing DGAT2 than in control cells.When cultured in DM or FA-DM for 12 d,cells overexpressing DGAT2 showed a higher proportion of unsaturated FAs（C16：1 and C18：1）.However,when cells overexpressing DGAT2 were cultured with FA-DM for30 min,the FA composition was almost identical to that of controls.Further,the proportion of stable isotope-labeled FAs were similar in 3T3-L1 adipocytes overexpressing DGAT2 and control cells cultured in IFA-DM for 12 d.These results collectively indicate that the higher proportion of mono-unsaturated FAs,C16：1 and C18：1,may originate from de novo FA synthesis but not from the uptake of specific FAs from the medium.This hypothesis is further supported by evidence that both mRNA and protein expression of genes involved in FA synthesis（ACACA,FASN,SCD1,and A-FABP）were significantly higher in cells overexpressing DGAT2 than in control cells.Conclusions：In conclusion,our study revealed that TAG accumulation,the proportion of MUFAs,and the expression of adipogenic genes were higher in 3T3-L1 cells overexpressing DGAT2 than in control cells.展开更多
The chemical composition of Pellonula leonensis fish oils from the Congo River (at Boko city) was carried out. The fatty acids were determined by gas chromatography. The Sn-2 position of fatty acids on glycerol was ca...The chemical composition of Pellonula leonensis fish oils from the Congo River (at Boko city) was carried out. The fatty acids were determined by gas chromatography. The Sn-2 position of fatty acids on glycerol was carried out by the ISO 6800 standard. The separation of the compounds (as free fatty acids, monoglycerides, diglycerides, triglycerides, sterols and methyl esters, etc.) was carried out by HPLC using gel permeation with refractometric detection. The phospholipid composition was by HPLC with an evaporative light scattering detector. We obtained oil contents of 32.10 (±0.46)%. The major fatty acids were Palmitic acid (27.41%) and oleic acid (24.23%). The SFA were of 44.50%. The MUFA represent 32.54% and PUFA 22.60%. Regarding the Sn-2 position on glycerol, 48.0% were by SFA and 51.3% were by unsaturated fatty acids. Among them 34.2% of fatty acids were 17.5% oleic acid molecules, 3.3% DHA molecules and 2.1% EPA molecules. Free fatty acids have contents of more than 62%, Diglycerides 16.63% and triglycerides 20.46%. Seven different phospholipids were identified, namely: Phosphatidylglycerol (PG), Phosphatidylethanolamine (PE), Phosphatidylinositol (PI), Phosphatidylcholine (PC), Sphingomyelin (SM), Lyso Phosphatitdylcholine (LPC) and Lyso Phosphatidylethanolamine (LPE). According to the high levels in position 2 of the glycerol of palmitic acid, the consumption of Pellonula leonensis fish could be moderate.展开更多
文摘Beef from Japanese Black cattle (JBK), is popular in Japan and valued for its highly marbled fat content. In JBK, genes affecting oleic acid content in meat have been studied mainly to lower the fat melting point and improve tenderness;however, there has been no direct correlation demonstrated between beef taste and oleic acid. To investigate genes affecting other fatty acids other than oleic acid, polymorphisms of the fatty acid desaturase 2 (FADS2) gene were genotyped and associations with fatty acid profile in JBK beef were investigated. Amplifications of 5’-flanking regions, 12 exons, and 3’-untranslated regions of the FADS2 gene in three Japanese and five Western cattle breeds via PCR, were amplified, sequenced and SNPs were identified using specific TaqMan genotyping assay. Fatty acid composition of intramuscular adipose tissue of the Trapezius muscle was analyzed in JBK steers. Six of the 15 identified SNPs are novel and have never been registered in any public bovine SNP database. A non-synonymous SNP (rs211580559;C > T;294 Ala > Val) in exon 7 was examined in order to evaluate its association with fatty acid profiles. The data showed that highly significant association existed between rs211580559 and C18:2 (n-6) composition, and accounted for 22.3% of the variation. There were no significant relationships between rs2115-80559 and the other fatty acids. It was concluded that rs211580559 of the FADS2 gene may be a useful selection marker for reducing unfavorable volatiles generated from linoleic acid in JBK beef during the cooking process.
基金supported by grants from the National Basic Research Program of China-the 973 Program(2012CB1247012013CB127306)+2 种基金the Talent Project of guangdong collegesthe Natural Science Foundation of Guangdong Province of China(S2012020011048)the Research Fund for the Doctoral Program of Higher Education
文摘Background：Fatty acid（FA） composition is the most important parameter affecting the flavor and nutritional value of the meat.The final and the only committed step in the biosynthesis of triglycerides is catalyzed by diacylglycerol acyltransferase 2（DGAT2）.The role of DGAT2 in lipid accumulation has been demonstrated in adipocytes,However,little is known about the effect of DGAT2 on the FA composition of these cells.Methods：To investigate the role of DGAT2 in regulating lipid accumulation,FA composition and the expression of adipogenic genes,we cloned the open reading frame of the porcine DGAT2 gene and established 3T3-L1 cells that overexpressed DGAT2.Cells were then cultured in differentiation medium（DM） without FA,with a mixture of FAs（FA-DM）,or containing a ^（13）C stable isotope-labeled FA mixture（IFA-DM）.The FA composition of adipocytes was analyzed by gas chromatography-mass spectrometry and gas chromatography-isotope ratio mass spectrometry.Quantitative PCR and western blotting were employed to detect expression of adipogenic genes in 3T3-L1 adipocytes cultured with FA-DM for 12 d.Results：The triacylglyceride（TAG） content was significantly higher in 3T3-L1 adipocytes overexpressing DGAT2 than in control cells.When cultured in DM or FA-DM for 12 d,cells overexpressing DGAT2 showed a higher proportion of unsaturated FAs（C16：1 and C18：1）.However,when cells overexpressing DGAT2 were cultured with FA-DM for30 min,the FA composition was almost identical to that of controls.Further,the proportion of stable isotope-labeled FAs were similar in 3T3-L1 adipocytes overexpressing DGAT2 and control cells cultured in IFA-DM for 12 d.These results collectively indicate that the higher proportion of mono-unsaturated FAs,C16：1 and C18：1,may originate from de novo FA synthesis but not from the uptake of specific FAs from the medium.This hypothesis is further supported by evidence that both mRNA and protein expression of genes involved in FA synthesis（ACACA,FASN,SCD1,and A-FABP）were significantly higher in cells overexpressing DGAT2 than in control cells.Conclusions：In conclusion,our study revealed that TAG accumulation,the proportion of MUFAs,and the expression of adipogenic genes were higher in 3T3-L1 cells overexpressing DGAT2 than in control cells.
文摘The chemical composition of Pellonula leonensis fish oils from the Congo River (at Boko city) was carried out. The fatty acids were determined by gas chromatography. The Sn-2 position of fatty acids on glycerol was carried out by the ISO 6800 standard. The separation of the compounds (as free fatty acids, monoglycerides, diglycerides, triglycerides, sterols and methyl esters, etc.) was carried out by HPLC using gel permeation with refractometric detection. The phospholipid composition was by HPLC with an evaporative light scattering detector. We obtained oil contents of 32.10 (±0.46)%. The major fatty acids were Palmitic acid (27.41%) and oleic acid (24.23%). The SFA were of 44.50%. The MUFA represent 32.54% and PUFA 22.60%. Regarding the Sn-2 position on glycerol, 48.0% were by SFA and 51.3% were by unsaturated fatty acids. Among them 34.2% of fatty acids were 17.5% oleic acid molecules, 3.3% DHA molecules and 2.1% EPA molecules. Free fatty acids have contents of more than 62%, Diglycerides 16.63% and triglycerides 20.46%. Seven different phospholipids were identified, namely: Phosphatidylglycerol (PG), Phosphatidylethanolamine (PE), Phosphatidylinositol (PI), Phosphatidylcholine (PC), Sphingomyelin (SM), Lyso Phosphatitdylcholine (LPC) and Lyso Phosphatidylethanolamine (LPE). According to the high levels in position 2 of the glycerol of palmitic acid, the consumption of Pellonula leonensis fish could be moderate.
