Experimental Evolutionary Studies of Temperate Adaptation: The Evolution of Bioenergetic and Growth Rate Responses of a Mesophilic Bacterium

温度的变化对生化反应的速率有显著的影响。我们知道温度的短期变化如何影响微生物的生长速度、呼吸和生长效率，但我们对这些因素在适应温度变化的进化过程中如何变化知之甚少。本研究将对比温度对大肠杆菌祖先菌株的能量学和生长的影响以及细菌在进化适应过程中发生的变化。从一种普通菌种衍生出的多种菌种将在新的热环境中培养，包括高温、低温和可变温度。对于每一个菌种，生长速率、呼吸速率以及细菌将食物转化为新细菌组织的效率都将被确定。这项研究将确定对特定热环境的适应如何改变细菌在其他热环境中生长和竞争的能力。多菌种选择实验的重复将揭示对新热环境的遗传反应的变异范围。这项研究将提高我们预测细菌对环境变化的长期反应的能力，这很重要，因为微生物是自然生态系统中重要的能量消费者和营养循环者。它将确定在不同温度下赋予适应优势的特征，并证明这些适应对生物能量学的影响。在不同温度下提高生长效率的性状的鉴定将在商业养殖操作中具有潜在价值。

9507416 Changes in temperature have significant effects on the rates of biochemical reactions. We know how short term changes in temperature affect the growth rate, respiration and growth efficiency of microbes, but we know relatively little about how these factors change during evolutionary adaptation to change in temperature. This research will contrast the effects of temperature on energetics and growth of ancestral strains of the bacterium Escherichia coli with changes that occur during evolutionary adaptation of the bacteria. Multiple lines of bacteria derived from a common stock will be cultured in new thermal environments, including high, low, and variable temperature. For each line, growth rate, respiration rate, and the efficiency with which the bacteria convert food into new bacterial tissue will be determined. The research will determine how adaptation to a particular thermal regime alters the ability of the bacteria to grow and compete in other thermal environments. Replication of selection experiments with multiple lines of bacteria will reveal the range of variation in genetic responses to new thermal environments. This research will increase our ability to predict the long term response of bacteria to environmental variation, which is important because microbes are important energy consumers and nutrient recyclers in natural ecosystems. It will identify traits that confer adaptive advantages at different temperatures, and demonstrate the impact of those adaptations on bioenergetics. The identification of traits that increase growth efficiency at different temperatures will be of potential value in commercial culture operations.