Rosberg-Cody Eva, Johnson Mark C, Fitzgerald Gerald F, Ross Paul R, Stanton Catherine
Microbiology Department, University College Cork, Ireland.
Teagasc, Moorepark Food Research, Biotechnology Centre, Fermoy, Co. Cork, Ireland.
Microbiology (Reading). 2007 Aug;153(Pt 8):2483-2490. doi: 10.1099/mic.0.2006/001966-0.
The linoleic acid isomerase enzyme from Propionibacterium acnes responsible for bioconversion of linoleic acid to trans-10, cis-12 conjugated linoleic acid (t10, c12 CLA) was cloned and overexpressed in Lactococcus lactis and Escherichia coli, resulting in between 30 and 50 % conversion rates of the substrate linoleic acid to t10, c12 CLA. The anti-proliferative activities of the fatty acids produced following isomerization of linoleic acid by L. lactis and E. coli were assessed using the human SW480 colon cancer cell line. Fatty acids generated from both L. lactis and E. coli contained a mixture of linoleic acid and t10, c12 CLA at a ratio of approximately 1.35 : 1. Following 5 days of incubation of SW480 cells with 5-20 microg ml(-1) (17.8-71.3 microM) of the t10, c12 CLA, there was a significant (P<0.001) reduction in growth of the SW480 cancer cells compared with the linoleic acid control. Cell viability after treatment with the highest concentration (20 microg ml(-1)) of the t10, c12 CLA was reduced to 7.9 % (L. lactis CLA) and 19.6 % (E. coli CLA), compared with 95.4 % (control linoleic acid) and 31.7 % (pure t10, c12 CLA). In conclusion, this is believed to represent the first report in which recombinant strains are capable of producing CLA with an anti-proliferative potential.
痤疮丙酸杆菌中负责将亚油酸生物转化为反式-10，顺式-12共轭亚油酸（t10，c12 CLA）的亚油酸异构酶被克隆，并在乳酸乳球菌和大肠杆菌中过表达，使得底物亚油酸向t10，c12 CLA的转化率达到30%至50%。使用人SW480结肠癌细胞系评估了乳酸乳球菌和大肠杆菌对亚油酸异构化后产生的脂肪酸的抗增殖活性。乳酸乳球菌和大肠杆菌产生的脂肪酸均含有亚油酸和t10，c12 CLA的混合物，比例约为1.35:1。用5-20微克/毫升（17.8-71.3微摩尔）的t10，c12 CLA孵育SW480细胞5天后，与亚油酸对照相比，SW480癌细胞的生长显著（P<0.001）减少。用最高浓度（20微克/毫升）的t10，c12 CLA处理后，细胞活力分别降至7.9%（乳酸乳球菌CLA）和19.6%（大肠杆菌CLA），而对照亚油酸为95.4%，纯t10，c12 CLA为31.7%。总之，这被认为是首次报道重组菌株能够产生具有抗增殖潜力的CLA。
