de Carvalho Carla C C R, Marques Marco P C, Hachicho Nancy, Heipieper Hermann J
Institute of Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisbon, Portugal,
Appl Microbiol Biotechnol. 2014 Jun;98(12):5599-606. doi: 10.1007/s00253-014-5549-2. Epub 2014 Mar 6.
Bacterial cells are known to adapt to challenging environmental conditions such as osmotic stress. However, most of the work done in this field describes the adaptation of growing populations where the new generations acquire traits that improve their ability to survive. In the present study, the responses of Rhodococcus erythropolis cells within the first 30 min after exposure to osmotic stress caused by sodium chloride were studied. The cells changed the total lipid fatty acid composition and also the net surface charge in the 30 min following exposure. Surprisingly, the cells produced a high percentage of polyunsaturated fatty acids. In the presence of 7.5 % NaCl, these polyunsaturated fatty acids, mainly eicosapentaenoic acid (C20:5ω3), arachidonic acid (C20:4ω6) and docosapentaenoic acid (C22:5ω3), comprise more than 36 % of the total fatty acids. The possible function of these very uncommon fatty acids in bacteria could be the decrease in the number of negatively charged groups in ion channels resulting in a repellence of the NaCl.
已知细菌细胞能够适应具有挑战性的环境条件，如渗透胁迫。然而，该领域的大多数研究描述的是生长群体的适应性，即新一代获得提高其生存能力的性状。在本研究中，研究了红平红球菌细胞在暴露于由氯化钠引起的渗透胁迫后的前30分钟内的反应。在暴露后的30分钟内，细胞改变了总脂质脂肪酸组成以及净表面电荷。令人惊讶的是，细胞产生了高比例的多不饱和脂肪酸。在7.5%氯化钠存在的情况下，这些多不饱和脂肪酸，主要是二十碳五烯酸（C20:5ω3）、花生四烯酸（C20:4ω6）和二十二碳五烯酸（C22:5ω3），占总脂肪酸的36%以上。这些非常罕见的脂肪酸在细菌中的可能功能可能是减少离子通道中带负电荷基团的数量，从而导致对氯化钠的排斥。
