TOXICITY OF SELECT ORGANIC ACIDS TO THE SLIGHTLY THERMOPHILIC ACIDOPHILE ACIDITHIOBACILLUS CALDUS
TOXICITY OF SELECT ORGANIC ACIDS TO THE SLIGHTLY THERMOPHILIC ACIDOPHILE ACIDITHIOBACILLUS CALDUS
复制标题
DOI：
10.1897/08-277.1
复制
发表时间：
2009-02-01
影响因子：
4.1
通讯作者：
Peyton, Brent M.
中科院分区：
文献类型：
--
作者：
Aston, John E.;Apel, William A.;Peyton, Brent M.
酸性钙硫杆菌是一种嗜热嗜酸菌，存在于商业生物采矿、酸性矿井排水系统和自然环境中。以前的研究表明，caldus是一种能在有氧条件下利用还原性硫化合物的化能营养自养生物。有机酸在低ph环境中对趋化养石生物尤其有毒，因为它们更容易扩散到细胞内并在细胞质内去质子化。本研究在批量条件下考察了草酰乙酸、丙酮酸、2-酮戊二酸、乙酸、苹果酸、琥珀酸和富马酸对caldus菌株BC13的毒性作用。所有被试有机酸均表现出一定的抑制作用。草酰乙酸在250 μ M的浓度下完全抑制生长，而其他有机酸在1000 ~ 5000 μ M的浓度下完全抑制生长。在这些实验中，有机酸的测量浓度随着时间的推移而降低，表明细胞吸收或同化。磷脂脂肪酸分析表明有机酸对细胞膜的影响。显著的差异包括有机酸存在时环脂肪酸的增加，这表明细胞包膜可能不稳定。这一点得到了场发射扫描电子显微照片的支持，照片显示，在有机酸存在的情况下，生长的细胞出现了气泡和脱落。
Acidithiobacillus caldus is a thermophilic acidophile found in commercial biomining, acid mine drainage systems, and natural environments. Previous work has characterized A. caldus as a chemolithotrophic autotroph capable of utilizing reduced sulfur compounds under aerobic conditions. Organic acids are especially toxic to chemolithotrophs in low-pH environments, where they diffuse more readily into the cell and deprotonate within the cytoplasm. In the present study, the toxic effects of oxaloacetate, pyruvate, 2-ketoglutarate, acetate, malate, succinate, and fumarate on A. caldus strain BC13 were examined under batch conditions. All tested organic acids exhibited some inhibitory effect. Oxaloacetate was observed to inhibit growth completely at a concentration of 250 mu M, whereas other organic acids were completely inhibitory at concentrations of between 1,000 and 5,000 mu M. In these experiments, the measured concentrations of organic acids decreased with time, indicating uptake or assimilation by the cells. Phospholipid fatty acid analyses indicated an effect of organic acids on the cellular envelope. Notable differences included an increase in cyclic fatty acids in the presence of organic acids, indicating possible instability of the cellular envelope. This was supported by field emission scanning-electron micrographs showing blebbing and sluffing in cells grown in the presence of organic acids.