Life on the 'mild' side: adaptation of an extremophile archaeon to a mesophilic lifestyle

“温和”的生活：极端微生物古菌适应中温生活方式

• 批准号: NE/X012662/1
• 负责人: Danna Gifford
• 金额: $ 10.27万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FX012662%2F1
• 关键词: Life; mild; side; adaptation; extremophile

Extremophilic organisms have evolved specialised adaptations for coping with harsh environments. Maintaining genomic integrity under such conditions requires high DNA replication fidelity and repair systems to prevent genome degradation. However, these systems may hinder the generation of novel genetic variation required to adapt to mesophilic conditions. The Aim of this project is to identify evolutionary transitions, and constraints on adaptation, that occur during adaptation of an extremophile archaeon to mesophilic conditions (i.e. environmental cooling and alkalinization). We will characterise mesophilic adaptation in Sulfolobus acidocaldarius, a thermoacidophilic archaeon with optimal growth at 75-80 degrees Celsius and pH 2-3. We will first assess whether S. acidocaldarius is mutation limited under mesophilic conditions. We will then use laboratory experimental evolution to gradually adapt S. acidocaldarius to decreased temperature and increased pH, and use genomic sequencing to identify key adaptive mutations. Finally, we will assess whether adapting to mesophilic conditions was preceded by, or associated with, an increase in mutation rate. We hypothesise that evolutionary 'potentiating' mutations will involve loss-of-function or function-reducing variation in one or more of the highly-specialised DNA repair and replication fidelity systems possessed by S. acidocaldarius. This work will determine, for the first time, both the environment-specific adaptations and the evolutionary mechanisms underpinning mesophilic adaptation. This will shed light on transitions between extremophile and mesophile lifestyles, as may have occurred early in the evolutionary history of life on Earth under changing environmental conditions, on both global and microscopic scales.

极端生物已经进化了专门的改编，以应对恶劣的环境。在这种情况下保持基因组完整性需要高的DNA复制保真度和修复系统，以防止基因组降解。但是，这些系统可能会阻碍适应中嗜性疾病所需的新遗传变异的产生。该项目的目的是识别在对中嗜性条件（即环境冷却和碱化）适应期间发生的进化转变和对适应的约束。我们将表征磺胺酸酸氧化磺胺硫酸糖（Sulfolobus Acidocaldarius）的嗜热适应，这是一种热酸性古老的古老的古老的古老的古老，在75-80摄氏度下，摄氏75-80摄氏度和pH 2-3。我们将首先评估在嗜嗜性条件下是否有限的酸性链球菌是突变的。然后，我们将使用实验室实验进化来逐渐适应酸性链球菌以降低温度并增加pH，并使用基因组测序来鉴定关键的适应性突变。最后，我们将评估适应中嗜嗜性疾病之前还是与突变率提高有关。我们假设进化的“增强”突变将涉及在一个或多个高度探索的DNA修复和复制忠诚度系统中具有功能丧失或降低功能的变化。这项工作将首次确定环境特异性适应和基于中介适应的进化机制。这将揭示出极端和中间人生活方式之间的过渡，就像在不断变化的环境条件下，在全球和微观尺度上，地球生命的进化史上可能发生的那样。