Microbial utilization, mobilization and uptake of elemental sulfur

微生物对元素硫（S0）的吸收和利用是一个具有挑战性的生物化学问题，因为S0具有极强的疏水性，几乎不溶于水。尽管如此，它仍然被大量的化能营养型和光营养型硫细菌所使用。这些生物体中S0的活化、吸收和转化在很大程度上尚未探索。基于我们最近的发现，即缺氧光养细菌Allochromatium vinosum可以吸收聚合链状硫，但不能吸收更稳定的环八硫，并使用创新方法（XANES光谱法、纳米壳微胶囊化）和经典的生理和分子遗传技术，我们想要解决以下问题：吸收哪些硫物种？细胞与硫的直接接触对硫的吸收是必要的吗？哪些蛋白质参与了这种相互作用？细胞动员和吸收元素硫的机制是什么？本研究将重点研究两种紫色硫细菌模式生物：（1）A. vinosum，Chromatiaceae科，形成细胞内硫球。操纵遗传学的方法是可用的。(2)嗜盐红旋菌（Halorhodospira halophila），外硫红旋菌科（Ectothiorhodospiraceae），形成细胞外硫球。一个完整的基因组序列是可用的，促进蛋白质组学研究。

The uptake and use of elemental sulfur (S0) by microorganisms is a challenging biochemical problem because S0 is extremely hydrophobic and virtually insoluble in water. Still, it is used by a large number of chemotrophic and phototrophic sulfur bacteria. Activation, uptake and transformation of S0 in these organisms are largely unexplored. Based on our recent finding that the anoxygenic phototrophic bacterium Allochromatium vinosum can take up polymeric chain-like sulfur but not the more stable cyclo-octasulfur and using a combination of innovative methods (XANES spectroscopy, microencapsulation with nanoshells) and classical physiological and molecular genetic techniques we want to solve the following questions: Which sulfur species are taken up? Is direct cell-sulfur contact necessary for sulfur uptake and which proteins are involved in this interaction? Which mechanisms are employed by the cells for mobilization and uptake of elemental sulfur? We will concentrate on two purple sulfur bacterial model organisms: (1) A. vinosum, family Chromatiaceae, forms intracellular sulfur globules. Methods for manipulative genetics are available. (2) Halorhodospira halophila, family Ectothiorhodospiraceae, forms extracellular sulfur globules. A complete genome sequence is available facilitating proteomic studies.