Combined solvent and water activity stresses on turgor regulation and membrane adaptation in Oceanimonas baumannii ATCC 700832
Combined solvent and water activity stresses on turgor regulation and membrane adaptation in Oceanimonas baumannii ATCC 700832
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DOI：
10.1023/a:1023348928376
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发表时间：
2003-01-01
影响因子：
2.6
通讯作者：
Cummings, SP
中科院分区：
文献类型：
--
作者：
Brown, GR;Sutcliffe, IC;Cummings, SP
鲍曼海洋单胞菌ATCC 700832是一种革兰氏阴性海洋细菌，能够将苯酚作为唯一碳源利用。研究了该细菌在基本培养基中以琥珀酸盐或苯酚为底物时耐受低水活度的能力。随着盐度增加，膜脂和蛋白质组成呈现出两个不同的适应阶段。首先，当氯化钠浓度从0.15%（w/v）（观察到生长的最低浓度）增加到1%氯化钠（w/v）时，膜中两性离子磷脂与阴离子磷脂的比例显著增加。同时，饱和脂肪酸与不饱和脂肪酸的比例以及总膜蛋白显著降低。当盐度从1%增加到7%氯化钠（w/v）时观察到第二个阶段，此时两性离子磷脂与阴离子磷脂的比例降低，膜蛋白增加。然而，饱和脂肪酸与不饱和脂肪酸的比例未受影响。盐度也影响了培养物对高浓度苯酚的耐受性。在0.15%氯化钠（w/v）中生长的培养物能够耐受12 mM苯酚，而在1%氯化钠（w/v）存在的情况下，培养物在高达20 mM苯酚中仍能继续生长，在7%氯化钠（w/v）中培养物能够耐受8 mM苯酚。当苯酚浓度处于可耐受的最大值时，也观察到膜磷脂和脂肪酸组成的变化。在这种情况下，与以4 mM苯酚为底物的培养物相比，两性离子磷脂与阴离子磷脂的比例在除7%氯化钠（w/v）培养物（无显著影响）外的所有盐度中降低了两倍。与以4 mM苯酚培养的培养物相比，在所有盐度中饱和脂肪酸与不饱和脂肪酸的比例均显著增加。
Oceanimonas baumannii ATCC 700832 is a Gram negative marine bacterium capable of utilising phenol as a sole carbon source. The ability of the bacterium to tolerate low water activity when utilising either succinate or phenol as a substrate in minimal medium was studied. The membrane lipid and protein composition showed two discreet adaptive phases as salinity increased. Firstly, when NaCl concentration was increased from 0.15% (w/v), the minimum at which growth was observed, to 1% NaCl (w/v), the ratio of zwitterionic to anionic phospholipids in the membrane increased significantly. At the same time the ratio of saturated to unsaturated fatty acids and the total membrane protein decreased significantly. The second phase was observed when salinity was increased from 1% to 7% NaCl (w/v) as the ratio of zwitterionic to anionic phospholipids decreased and membrane protein increased. However, the ratio of saturated to unsaturated fatty acids was unaffected. Salinity also affected the tolerance of cultures to elevated levels of phenol. Cultures grown in 0.15% NaCl (w/v) could tolerate 12 mM phenol, whereas in the presence of 1% NaCl (w/v) cultures continued to grow in up to 20 mM phenol and in 7% NaCl (w/v) cultures 8 mM phenol could be tolerated. Changes to the composition of the membrane phospholipids and fatty acids were also observed when phenol concentrations were at the maximum that could be tolerated. Under such conditions the ratio of zwitterionic to anionic phospholipids decreased twofold compared to cultures utilising 4 mM phenol as the substrate, in all salinities except in 7% NaCl (w/v) cultures, where there was no significant effect. The ratio of saturated to unsaturated fatty acids increased significantly in all salinities compared to cultures grown with 4 mM phenol.