Genomic factors contributing to the upper temperature growth limits of bacteria

所有有生命的有机体的生长都有温度上限。纵观地球历史，平均气温有过几次变化，但目前的气候变化可能是自约6000万年前古新世-始新世最热时期以来最快的变暖周期之一。地球上的生物将不得不适应这些变化，许多生物将进化出对高温的更大抵抗力。*在这项建议中，我们研究了细菌使用的一些热适应。在之前的一系列实验室实验中，我们发现有证据表明，细菌用来适应致命温度的一种机制是增加一种不耐热的蛋白质的表达。这是通过改变蛋白质从信使RNA翻译的速度来实现的。另一种可能的机制是，另一种有助于保持不耐热蛋白质完整性的未知蛋白质被大量合成，最终结果是不耐热蛋白质实际上具有更长的半衰期。在拟议的研究中，我们将确定增加蛋白质翻译和其他机制是否在细菌适应更高的温度方面发挥重要作用。*从拟议的研究中获得的知识将有助于我们理解适应更温暖的温度。此外，这些结果将有助于指导生物制造中使用的耐高温细菌的实验室进化。重要的是，耐热性往往与对工业生产的化学品(如酒精)的抵抗力有关，我们的研究可能有助于创造出能够承受更高浓度的生物燃料的细菌。

All living organisms have an upper temperature limit to their growth. Throughout earth's history there have been several shifts in its average temperature, but the current climate change may be one of the fastest warming cycles since the Paleocene-Eocene Thermal Maximum which occurred about 60 M years ago. Organisms on earth will have to adapt to these changes, and many will evolve a greater resistance to heat. *** In this proposal we examine some of the heat adaptations that bacteria use. In a laboratory series of experiments we previously found evidence that one mechanism bacteria use to adapt to a lethal temperature is to increase the expression of a thermo-labile protein. This is accomplished by changing the rate that the protein is translated from the messenger RNA. Another presumed mechanism is that another, unknown protein, that helps preserve the integrity of thermo-labile proteins, is made in larger amounts, and the end result is that thermo-labile proteins effectively have longer half-lives. In the proposed research we will determine if increased protein translation and other mechanisms play an important role in the adaptation of bacteria to higher temperatures. *** The knowledge gained from the proposed research will contribute to our understanding of adaptation to warmer temperatures. In addition the results will help guide laboratory-evolution of temperature-resistant bacteria used in bio-manufacturing. Importantly, thermo-resistance often correlates with resistance to industrially-produced chemicals, such as alcohols, and our research may help to create bacteria that can withstand higher concentrations of the bio-fuels that they produce.