Elemental economy: microbial strategies for optimizing growth in the face of nutrient limitation.
Elemental economy: microbial strategies for optimizing growth in the face of nutrient limitation.
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DOI：
10.1016/b978-0-12-398264-3.00002-4
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发表时间：
2012
影响因子：
--
通讯作者：
Helmann, John D.
中科院分区：
文献类型：
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作者：
Merchant, Sabeeha S.;Helmann, John D.
微生物在营养物质的地球化学循环中起着主导作用。它们因其将碳和氮固定到有机物中的设施而受到正确的赞扬，微生物驱动的过程已经明显改变了生物圈及其周围大气的化学组成。尽管微生物具有惊人的分子转化能力，但在元素的不可改变性面前却无能为力。对特定元素的限制，无论是短暂的还是持续的，都在微生物的基因组、生理学及其原子组成上留下了不可磨灭的痕迹。本文综述了元素限制对微生物的影响，重点介绍了海洋生态系统中的遗传模式系统和代表性微生物。基因组和蛋白质组分析表明，在面对持续或反复出现的元素限制时，进化适应性增强了生长。这些变化范围从极端（例如免除对难以获得的元素的要求）到极其微妙（蛋白质氨基酸序列的变化，轻微但显着地减少细胞对碳，氮或硫的需求）。一种近乎普遍的适应是发展复杂的适应程序，通过这种程序，细胞调整其化学成分以应对不断变化的环境。当特定的因素变得有限，驯化通常开始增加承诺收购和随之而来的动员储存的资源。如果元素限制持续存在，细胞实施紧缩措施，包括元素节约和元素回收。对这些基本细胞特性的见解已经从许多不同层次的研究中出现;包括生态学，生物海洋学，生物地球化学，分子遗传学，基因组学和微生物生理学。在这里，我们提出了这些不同的研究综合，并试图辨别一些总体主题。
Microorganisms play a dominant role in the biogeochemical cycling of nutrients. They are rightly praised for their facility at fixing both carbon and nitrogen into organic matter, and microbial driven processes have tangibly altered the chemical composition of the biosphere and its surrounding atmosphere. Despite their prodigious capacity for molecular transformations, microorganisms are powerless in the face of the immutability of the elements. Limitations for specific elements, either fleeting or persisting over eons, have left an indelible trace on microbial genomes, physiology, and their very atomic composition. We here review the impact of elemental limitation on microbes, with a focus on selected genetic model systems and representative microbes from the ocean ecosystem. Evolutionary adaptations that enhance growth in the face of persistent or recurrent elemental limitations are evident from genome and proteome analyses. These range from the extreme (such as dispensing with a requirement for a hard to obtain element) to the extremely subtle (changes in protein amino acid sequences that slightly, but significantly, reduce cellular carbon, nitrogen, or sulfur demand). One near universal adaptation is the development of sophisticated acclimation programs by which cells adjust their chemical composition in response to a changing environment. When specific elements become limiting, acclimation typically begins with an increased commitment to acquisition and a concomitant mobilization of stored resources. If elemental limitation persists, the cell implements austerity measures including elemental-sparing and elemental-recycling. Insights into these fundamental cellular properties have emerged from studies at many different levels; including ecology, biological oceanography, biogeochemistry, molecular genetics, genomics, and microbial physiology. Here, we present a synthesis of these diverse studies and attempt to discern some overarching themes.