Liu Songling, Ren Fazheng, Jiang Jingli, Zhao Liang
The Innovation Centre of Food Nutrition and Human Health (Beijing), China Agricultural University, Beijing 100083, P.R. China.
Higher Institution Engineering Research Center of Animal Product, Beijing 10083, P.R. China.
J Microbiol Biotechnol. 2016 Jul 28;26(7):1190-7. doi: 10.4014/jmb.1511.11013.
The acid response of Bifidobacterium longum subsp. longum BBMN68 has been studied in our previous study. The fab gene, which is supposed to be involved in membrane fatty acid biosynthesis, was demonstrated to be induced in acid response. In order to investigate the relationship between acid response and cell membrane fatty acid composition, the acid adaptation of BBMN68 was assessed and the membrane fatty acid composition at different adaptation conditions was identified. Indeed, the fatty acid composition was influenced by acid adaptation. Our results showed that the effective acid adaptations were accompanied with decrease in the unsaturated to saturated fatty acids ratio (UFA/SFA) and increase in cyclopropane fatty acid (CFA) content, which corresponded to previous studies. Moreover, both effective and non-effective acid adaptation conditions resulted in decrease in the C18:1 cis-9/C18:1 trans-9 ratio, indicating that the C18:1 cis-9/C18:1 trans-9 ratio is associated with acid tolerance response but not with acid adaptation response. Taken together, this study indicated that the UFA/SFA and CFA content of BBMN68 were involved in acid adaptation and the C18:1 cis-9/C18:1 trans-9 ratio was involved in acid tolerance response.
在我们之前的研究中，已经对长双歧杆菌长亚种BBMN68的酸响应进行了研究。假定参与膜脂肪酸生物合成的fab基因在酸响应中被证明会被诱导。为了研究酸响应与细胞膜脂肪酸组成之间的关系，评估了BBMN68的酸适应性，并确定了不同适应条件下的膜脂肪酸组成。事实上，脂肪酸组成受到酸适应性的影响。我们的结果表明，有效的酸适应性伴随着不饱和脂肪酸与饱和脂肪酸比例（UFA/SFA）的降低和环丙烷脂肪酸（CFA）含量的增加，这与之前的研究结果一致。此外，有效的和无效的酸适应条件均导致C18:1顺式-9/C18:1反式-9比例降低，表明C18:1顺式-9/C18:1反式-9比例与耐酸响应有关，但与酸适应响应无关。综上所述，本研究表明BBMN68的UFA/SFA和CFA含量参与酸适应，而C18:1顺式-9/C18:1反式-9比例参与耐酸响应。
