LExEN: Life in Acid

LExEN：酸中的生活

• 批准号: 9978205
• 负责人: Jillian Banfield
• 金额: $ 45万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-10-01 至 2003-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9978205&HistoricalAwards=false
• 关键词: LExEN; Life; Acid

9978205BanfieldUnusual microorganisms thrive in hot, extremely acidic solutions associated with weathered pyrite-rich rocks. Prior work has documented a dynamic archaeal, bacterial, and eukaryotic community in 30 - 50 degrees C, pH 0 - 1.0 solutions. Reduced iron and sulfur from pyrite are key microbial energy sources. Microbes that catalyze the oxidation of Fe2+ dramatically impact sulfuric acid generation rates. Populations of lithotrophs and heterotrophs vary with temperature, solution composition, pH, and location. This project will explore how these populations change with changes in geochemical conditions and determine the specific acid and ionic strength resistance and energy generation mechanisms that allow microbial communities to exist in extremely acidic environments. In general, little is known about the identity and survival strategies of the majority of members of extremely acidiphilic microbial communities. A novel mesothermophilic iron-oxidizing archaea (Ferromonas acidiphilium) has been isolated from a field site at Iron Mountain, CA. Additional species will be isolated from samples known to contain the little studied Acidomicrobium ferrooxidans and previously recognized and new relatives of "Leptospirillum ferrooxidans". Isolates will be used in biochemical investigations. Many organisms from this site have not been identified; these will be the focus of further sequencing and isolation efforts. It is anticipated that cells will employ passive pH resistance mechanisms (involving cell membrane constituents, possibly in conjunction with S-layers). Thus, the dependence of cell wall composition (i.e., fatty acids and/or proteins) on growth conditions will be explored, and thereby possible resistance mechanisms evaluated. Prior work indicates that cytochromes other than rusticyanin (used by Thiobacillus ferrooxidans) are important for iron oxidation by bacterial and archaeal species. Relevant cytochromes will be identified in order to evaluate the diversity of energy generation mechanisms that underpin the ecosystem.

9978205班菲尔德不寻常的微生物在与风化的富含黄铁矿的岩石相关的高温、极酸性溶液中茁壮成长。先前的工作已经记录了30 - 50摄氏度，pH 0 - 1.0溶液中的动态古菌，细菌和真核生物群落。 黄铁矿中的还原铁和硫是重要的微生物能源。催化Fe 2+氧化的微生物显著影响硫酸产生速率。石养生物和异养生物的种群随温度、溶液组成、pH和位置而变化。该项目将探索这些种群如何随着地球化学条件的变化而变化，并确定特定的酸和离子强度阻力以及允许微生物群落在极端酸性环境中存在的能量产生机制。 在一般情况下，很少有人知道的身份和生存策略的大多数成员的极端嗜酸微生物群落。 一种新的嗜中温铁氧化古菌（Ferromonas acidophilium）已从加利福尼亚州铁山的一个现场分离出来。将从已知含有很少研究的氧化亚铁酸微菌和以前认识到的“氧化亚铁纤微菌”的新亲戚的样品中分离出其他菌种。 分离株将用于生化研究。该研究中心的许多微生物尚未鉴定;这些将是进一步测序和分离工作的重点。预计细胞将采用被动pH抗性机制（涉及细胞膜成分，可能与S层结合）。 因此，细胞壁组成的依赖性（即，脂肪酸和/或蛋白质）对生长条件的影响，从而评估可能的抗性机制。 先前的工作表明，除了rusticyanin（由氧化亚铁硫杆菌使用）之外的细胞色素对细菌和古细菌物种的铁氧化很重要。将确定相关的细胞色素，以评估支撑生态系统的能量产生机制的多样性。