LEXEN: Adaptations of Unicellular Eukaryotes to Extremely Acidic Environments

deb - 0085486 -米切尔SoginDr。马萨诸塞州伍兹霍尔海洋生物实验室的米切尔·索金（Mitchell Sogin）获得了一项资助，研究真核微生物对极端酸性环境的适应。对极端环境下生命的研究很少关注真核微生物。然而，有明确的证据表明，原生生物栖息并有时主导着非常酸性或非常碱性的生态系统。一个特别有趣的系统是里约热内卢Tinto，它是西班牙西南部的一个河流盆地。这是一个酸性环境，pH值在1.7-2.5之间，铁浓度高达20毫克/毫升。这条河并不直接支持多细胞动物，但它充满了真核微生物，有时占生物量的65%。本提案的目标是定义里约热内卢Tinto中的原生生物多样性，并探索可能允许真核微生物在这种极端环境中生长的生理机制的变化。Sogin的团队将结合培养和分子技术来估计原生生物的多样性。从里约热内卢Tinto生物膜样品中分离的基因序列的分子研究将提供原生生物多样性的估计。这些将与可以带入文化的原生生物的多样性进行比较。他们还将使用培养分离物来探索生理特性的自然变化，这些生理特性是嗜酸原生生物种群稳定性的基础。我们将确定在极低pH下生长需要对现有真核生物机制进行哪些修改，以及真核生物如何适应极端酸性环境。

DEB-0085486Mitchell SoginDr. Mitchell Sogin of the Marine Biological Laboratory at Woods Hole, MA has been awarded a grant to study the adaptation of eukaryotic microorganisms to extremely acidic environments. Studies of life in extreme environments rarely focus upon eukaryotic microbes. Yet there is clear evidence that protists inhabit and sometimes dominate ecosystems that are either very acidic or very alkaline. A particularly interesting system is the Rio Tinto, a river basin in southwestern Spain. This is an acidic environment where the pH ranges from 1.7-2.5 and iron concentrations are as high as 20 mg/ml. The river does not directly support multi-cellular animals but it is teeming with eukaryotic microbes, sometimes representing as much as 65% of the biomass. The goal of this proposal is to define protist diversity in the Rio Tinto and to explore alterations in physiological mechanisms that might allow the growth of eukaryotic microbes in this extreme environment. Sogin's team will use a combination of culturing and molecular techniques to estimate protist diversity. Molecular studies of gene sequences that have been isolated from the Rio Tinto biofilm samples will provide estimates of protist diversity. These will be compared to the diversity of protists that can be brought into culture. They will also use the culture isolates to explore natural variation in physiological properties that underlie the stability of acidophilic protist populations. We will determine what modifications to existing eukaryotic mechanisms are necessary for growth at extremely low pH and how eukaryotes have adapted to extreme acid environments.