Genetic modifi cation is useful for improving the nutritional qualities of cyanobacteria. To increase the total unsaturated fatty acid content, along with the ratio of ω-3/ω-6 fatty acids, genetic engineering can be...Genetic modifi cation is useful for improving the nutritional qualities of cyanobacteria. To increase the total unsaturated fatty acid content, along with the ratio of ω-3/ω-6 fatty acids, genetic engineering can be used to modify fatty acid metabolism. S ynechococcus sp. PCC7002, a fast-growing cyanobacterium, does not contain a Δ6 desaturase gene and is therefore unable to synthesize γ-linolenic acid(GLA) and stearidonic acid(SDA), which are important in human health. In this work, we constructed recombinant vectors Syd6 D, Syd15 D and Syd6Dd15 D to express the Δ15 desaturase and Δ6 desaturase genes from Synechocystis PCC6803 in Synechococcus sp. PCC7002, with the aim of expressing polyunsaturated fatty acids. Overexpression of the Δ15 desaturase gene in S ynechococcus resulted in 5.4 times greater accumulation of α-linolenic acid compared with the wild-type while Δ6 desaturase gene expression produced both GLA and SDA. Co-expression of the two genes resulted in low-level accumulation of GLA but much larger amounts of SDA, accounting for as much to 11.64% of the total fatty acid content.展开更多
This study evaluates the incorporation of alpha-linolenic acid （LNA, 18：3n-3） through the golden flaxseed in snacks＇ formulations with and without seasoning. Snacks with different formulations presented significan...This study evaluates the incorporation of alpha-linolenic acid （LNA, 18：3n-3） through the golden flaxseed in snacks＇ formulations with and without seasoning. Snacks with different formulations presented significant differences （P 〈 0.05） in their proximate composition, mainly for total lipids and moisture content. Regarding the fatty acids profile, six different fatty acids were found： 16：0, 18：0, 18：1n-9, 18：1n-7, 18：2n-6 （LA） and 18：3n-3. The majority fatty acid was 18：2n-6 （LA） due to the predominance of corn in the products formulation. The incorporation of 18：3n-3 was observed, and this fatty acid was not affected by the extrusion temperature during the processing or the storage time. The results of sensory evaluation indicated that the product developed with addition of golden flaxseed had mild acceptance among the panelists. Thus, it was concluded that the addition of flaxseed is feasible for the nutritional enrichment of corn snacks.展开更多
基金Supported by the International S&T Cooperation Program of China(No.2012DFA30450)the National Natural Science Foundation of China(No.30871541)+1 种基金the Taishan Scholar Foundation of Shandong Province(No.tshw20091014)the Innovation Program of the University Institutes of Jinan,Shandong Province(No.201004044)
文摘Genetic modifi cation is useful for improving the nutritional qualities of cyanobacteria. To increase the total unsaturated fatty acid content, along with the ratio of ω-3/ω-6 fatty acids, genetic engineering can be used to modify fatty acid metabolism. S ynechococcus sp. PCC7002, a fast-growing cyanobacterium, does not contain a Δ6 desaturase gene and is therefore unable to synthesize γ-linolenic acid(GLA) and stearidonic acid(SDA), which are important in human health. In this work, we constructed recombinant vectors Syd6 D, Syd15 D and Syd6Dd15 D to express the Δ15 desaturase and Δ6 desaturase genes from Synechocystis PCC6803 in Synechococcus sp. PCC7002, with the aim of expressing polyunsaturated fatty acids. Overexpression of the Δ15 desaturase gene in S ynechococcus resulted in 5.4 times greater accumulation of α-linolenic acid compared with the wild-type while Δ6 desaturase gene expression produced both GLA and SDA. Co-expression of the two genes resulted in low-level accumulation of GLA but much larger amounts of SDA, accounting for as much to 11.64% of the total fatty acid content.
文摘This study evaluates the incorporation of alpha-linolenic acid （LNA, 18：3n-3） through the golden flaxseed in snacks＇ formulations with and without seasoning. Snacks with different formulations presented significant differences （P 〈 0.05） in their proximate composition, mainly for total lipids and moisture content. Regarding the fatty acids profile, six different fatty acids were found： 16：0, 18：0, 18：1n-9, 18：1n-7, 18：2n-6 （LA） and 18：3n-3. The majority fatty acid was 18：2n-6 （LA） due to the predominance of corn in the products formulation. The incorporation of 18：3n-3 was observed, and this fatty acid was not affected by the extrusion temperature during the processing or the storage time. The results of sensory evaluation indicated that the product developed with addition of golden flaxseed had mild acceptance among the panelists. Thus, it was concluded that the addition of flaxseed is feasible for the nutritional enrichment of corn snacks.
