Influence of the growth at high osmolality on the lipid composition, water permeability and osmotic response of Lactobacillus bulgaricus
Influence of the growth at high osmolality on the lipid composition, water permeability and osmotic response of Lactobacillus bulgaricus
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DOI：
10.1016/j.abb.2005.09.004
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发表时间：
2005-11-15
影响因子：
3.9
通讯作者：
Disalvo, EA
中科院分区：
文献类型：
--
作者：
Tymczyszyn, EE;Gómez-Zavaglia, A;Disalvo, EA
水的渗透性和膜包装的变化进行了测量，在保加利亚乳杆菌的细胞和从他们提取的脂质制备的囊泡。全细胞和囊泡的渗透反应进行了比较，在高渗透压介质中生长的细菌之一。细菌和囊泡都具有渗透压计的作用。这意味着体积减少是由NaCl浓度差驱动的水流出促进的，认为在这些条件下Na+和Cl-都不渗透细胞或脂质膜。因此，体积变化可以与水渗透穿过细胞或囊泡膜的速率相关。通过测量脂质的体积变化和饱和比，分析水的渗透作为脂质种类的函数。为了使膜过程相关，还分析了用从在正常和高渗透压条件下生长的细菌中提取的脂质制备的脂质囊泡的渗透性质。利用二苯基己三烯（DPH）的荧光各向异性，研究了细胞膜和囊泡膜的物理性质与渗透响应的关系。膜性质的改变与在高渗透压介质中生长所引发的膜组成的变化有关。这些变化似乎与整个脂质池的糖含量和饱和脂肪酸残基的增加有关。(c)2005年爱思唯尔公司All rights reserved.
Changes in water permeability and membrane packing were measured in cells of Lactobacillus bulgaricus and in vesicles prepared with lipids extracted from them. The osmotic response of whole cells and vesicles is compared with the one of bacteria grown in a high osmolal medium. Both bacteria and vesicles, behave as osmometers. This means that the volume decrease is promoted by the outflow of water, driven by the NaCl concentration difference, arguing that neither Na+ nor Cl- permeates the cell or the lipid membrane in these conditions. Therefore, the volume changes can be correlated with the rate of water permeation across the cell or the vesicle membranes. The permeation of water was analyzed as a function of the lipid species by measuring the volume changes and the saturation ratio of the lipids. To put into relevance the membrane processes, the permeation properties of lipid vesicles prepared with lipids extracted from bacteria grown in normal and high osmolality conditions were also analyzed. The permeation response was correlated with the physical properties of the membrane of whole cells and vesicles, by means of fluorescence anisotropy of diphenyl hexatriene (DPH). The modifications in membrane properties are related with the changes in the membrane composition triggered by the growth in a high osmolal medium. The changes appear related to an increase in the sugar content of the whole pool of lipids and in the saturated fatty acid residues. (c) 2005 Elsevier Inc. All rights reserved.