Stabilization of model membranes during drying by compatible solutes involved in the stress tolerance of plants and microorganisms
Stabilization of model membranes during drying by compatible solutes involved in the stress tolerance of plants and microorganisms
复制标题
DOI：
10.1042/bj20040746
复制
发表时间：
2004-10-15
影响因子：
4.1
通讯作者：
Hagemann, M
中科院分区：
文献类型：
--
作者：
Hincha, DK;Hagemann, M
许多生物在环境胁迫条件下积累相容性溶质。蓝细菌积累兼容的溶质响应增加的外部盐度，从苏（蔗糖）或海藻糖2-O-（α-D-glcopyranosyl）-甘油和甘氨酸甜菜碱积累物种的耐受性增加。目前尚不清楚这些不同的溶质如何影响耐盐性。一种可能的解释可能是这些溶质在应力条件下稳定膜的能力不同。因此，我们在相容性溶质存在下用脂质体进行干燥实验。Sue、海藻糖和山梨糖醇保护脂质体在干燥和再水化过程中不发生可溶性标记物渗漏和膜融合。2-O-（α-D-吡喃葡萄糖基）甘油的效果较差，甘氨酸甜菜碱几乎没有任何效果。与Sue组合，后两种溶质显示出改善的保护。已知脂质相变有助于溶质从脂质体中渗漏。我们确定在干膜中的溶质的存在或不存在的相变，使用傅立叶变换红外光谱。溶质降低相变温度的能力与其保护脂质体免受溶质泄漏的能力密切相关。所有溶质与脂质头基中的磷酸盐相互作用。在不对称的P=O伸缩振动的位移的幅度密切相关的脂质相变温度。这表明溶质提供的膜保护程度主要取决于其与膜脂质相互作用的能力。然而，这并不是细胞对盐胁迫的保护的决定因素，因为溶质在对这些胁迫的保护方面排名时显示出相反的顺序。
Many organisms accumulate compatible solutes under environmental stress conditions. Cyanobacteria accumulate compatible solutes in response to increased external salinity, with tolerance increasing from Sue (sucrose) or trehalose to 2-O-(alpha-D-ghlcopyranosyl)-glycerol and glycinebetaine accumulating species. It is not clear how these different solutes influence salt tolerance. One possible explanation may be a differential ability of these solutes to stabilize membranes under stress conditions. We therefore performed drying experiments with liposomes in the presence of compatible solutes. Sue, trehalose and sorbitol protected liposomes from leakage of a soluble marker and from membrane fusion during drying and rehydration. 2-O-(alpha-D-glucopyranosyl)glycerol was less effective and glycinebetaine showed hardly any effect. In combination with Sue, the latter two solutes showed improved protection. Lipid-phase transitions are known to contribute to solute leakage from liposomes. We determined phase transitions in dry membranes in the absence or presence of the solutes, using Fourier-transform infrared spectroscopy. The ability of the solutes to decrease the phase transition temperature corresponded closely to their ability to protect the liposomes against solute leakage. All solutes interacted with the phosphate in the lipid headgroups. The magnitude of the shift in the asymmetric P=O stretching vibration correlated closely with the lipid-phase transition temperature. This indicates that the degree of membrane protection afforded by the solutes is mainly determined by their ability to interact with the membrane lipids. However, this is not a determinant of cellular protection against salt stress, as the solutes show a reverse order when ranked with regard to protection against these stresses.