Chlorobaculum tepidum modulates amino acid composition in response to energy availability, as revealed by a systematic exploration of the energy landscape of phototrophic sulfur oxidation
Chlorobaculum tepidum modulates amino acid composition in response to energy availability, as revealed by a systematic exploration of the energy landscape of phototrophic sulfur oxidation
复制标题
对光养硫氧化能量景观的系统探索揭示了温绿杆菌根据能量可用性调节氨基酸组成
DOI：
10.1128/aem.02111-16
复制
发表时间：
2016
影响因子：
4.4
通讯作者：
Hanson, Thomas E.
中科院分区：
文献类型：
--
作者：
Levy, Amalie T.;Lee, Kelvin H.;Hanson, Thomas E.
微生物硫代谢，特别是不溶性元素硫（SO）的形成和消耗，是一个重要的生物地球化学引擎，已被利用的应用范围从生物沥滤和生物采矿的废物流的修复。暗绿杆菌是一种光自养硫氧化细菌，能氧化多种硫物种，并表现出对更多还原电子供体的偏好：硫化物> S0>硫代硫酸盐。为了理解这种偏好的背景下，光能利用率，“能源景观”的光养硫氧化构建不同的电子供体身份，光通量，和文化的持续时间。生物量和细胞参数。分析了在这片土地上生长的温带文化。根据这些数据，开发了比色蛋白测定的校正因子，从而能够更准确地测量C. tepidum，以及其他生物。C. tepidum的散装氨基酸组成与能源景观参数，包括减少光通量下的倾向于较低的能量昂贵的氨基酸。这种相关性，再加上在富电子生长条件下观察到的细胞大小和储存碳产量的增加，表明C。tepidum已经进化到通过调整其蛋白质组以获得能量效率和储存化合物以科普不断变化的能量可用性。重要信息微生物如何科普和适应不同的能量可用性是理解微生物生态学和设计有效生物技术过程的重要因素。我们探讨了一个模型的光养生物，绿杆菌tepidum，在析因实验设计，使同时变化和分析多种生长条件下，我们称之为“能源景观”的反应。C. tepidum生物质组成在低光照水平下向能量较低的昂贵氨基酸转移。这一观察结果为微生物蛋白质组的进化效率提供了实验证据，并强调了能量通量在生物体适应性反应中可能发挥的作用。从实际的角度来看，我们的数据表明，散装生物质氨基酸组成可以提供一个简单的代理，以监测和识别微生物系统中的能量应力。
Microbial sulfur metabolism, particularly the formation and consumption of insoluble elemental sulfur (S0), is an important biogeochemical engine that has been harnessed for applications ranging from bioleaching and biomining to remediation of waste streams. Chlorobaculum tepidum, a low-light-adapted photoautolithotrophic sulfur-oxidizing bacterium, oxidizes multiple sulfur species and displays a preference for more reduced electron donors: sulfide > S0> thiosulfate. To understand this preference in the context of light energy availability, an “energy landscape” of phototrophic sulfur oxidation was constructed by varying electron donor identity, light flux, and culture duration. Biomass and cellular parameters of C. tepidum cultures grown across this landscape were analyzed. From these data, a correction factor for colorimetric protein assays was developed, enabling more accurate biomass measurements for C. tepidum, as well as other organisms. C. tepidum's bulk amino acid composition correlated with energy landscape parameters, including a tendency toward less energetically expensive amino acids under reduced light flux. This correlation, paired with an observation of increased cell size and storage carbon production under electron-rich growth conditions, suggests that C. tepidum has evolved to cope with changing energy availability by tuning its proteome for energetic efficiency and storing compounds for leaner times.IMPORTANCEHow microbes cope with and adapt to varying energy availability is an important factor in understanding microbial ecology and in designing efficient biotechnological processes. We explored the response of a model phototrophic organism, Chlorobaculum tepidum, across a factorial experimental design that enabled simultaneous variation and analysis of multiple growth conditions, what we term the “energy landscape.” C. tepidum biomass composition shifted toward less energetically expensive amino acids at low light levels. This observation provides experimental evidence for evolved efficiencies in microbial proteomes and emphasizes the role that energy flux may play in the adaptive responses of organisms. From a practical standpoint, our data suggest that bulk biomass amino acid composition could provide a simple proxy to monitor and identify energy stress in microbial systems.