Levels of Ca2+-dipicolinic acid in individual Bacillus spores determined using microfluidic raman tweezers
Levels of Ca2+-dipicolinic acid in individual Bacillus spores determined using microfluidic raman tweezers
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DOI：
10.1128/jb.00282-07
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发表时间：
2007-07-01
影响因子：
3.2
通讯作者：
Li, Yong-Qing
中科院分区：
文献类型：
--
作者：
Huang, Shu-Shi;Chen, De;Li, Yong-Qing
吡啶-2，6-二羧酸(DPA)与钙离子形成1：1的螯合物(Ca-DPA)，占芽孢杆菌孢子干重的5%~15%。CA-DPA在孢子对许多环境胁迫的抗性和孢子稳定性方面是重要的，孢子种群中的Ca-DPA水平可以随着孢子种类/菌株的不同而变化，也可以随着产孢量的变化而变化。我们用微流控拉曼光谱仪测量了各种芽孢杆菌种群中大量单个孢子中的Ca-DPA水平，其中单个孢子被聚焦的激光捕获，其Ca-DPA是根据拉曼光谱中位于1,017 cm(-1)的Ca-DPA特异带的强度来定量的。这些测量得出的结论包括：(I)孢子芯中的Ca-DPA浓度为800 mM，远高于Ca-DPA的溶解度；(Ii)SpoVA蛋白可能参与了孢子形成过程中对Ca-DPA的吸收；(Iii)群体中不同孢子之间的Ca-DPA水平存在显著差异，但这种差异很大程度上可能是由于单个孢子的大小不同所致。
Pyridine-2,6-dicarboxylic acid (dipicolinic acid [DPA]) in a 1:1 chelate with calcium ion (Ca-DPA) comprises 5 to 15% of the dry weight of spores of Bacillus species. Ca-DPA is important in spore resistance to many environmental stresses and in spore stability, and Ca-DPA levels in spore populations can vary with spore species/strains, as well as with sporulation conditions. We have measured levels of Ca-DPA in large numbers of individual spores in populations of a variety of Bacillus species and strains by using microfluidic Raman tweezers, in which a single spore is trapped in a focused laser beam and its Ca-DPA is quantitated from the intensity, of the Ca-DPA-specific band at 1,017 cm(-1) in Raman spectroscopy. Conclusions from these measurements include the following: (i) Ca-DPA concentrations in the spore core are > 800 mM, well above Ca-DPA solubility; (ii) SpoVA proteins may be involved in Ca-DPA uptake in sporulation; and (iii) Ca-DPA levels differ significantly among individual spores in a population, but much of this variation could be due to variations in the sizes of individual spores.