School of Biological Sciences, Medical Biology Centre, Queen's University, Belfast BT9 7BL, Northern Ireland.
Proc Natl Acad Sci U S A. 2010 Apr 27;107(17):7835-40. doi: 10.1073/pnas.1000557107. Epub 2010 Apr 19.
Microbial cells, and ultimately the Earth's biosphere, function within a narrow range of physicochemical conditions. For the majority of ecosystems, productivity is cold-limited, and it is microbes that represent the failure point. This study was carried out to determine if naturally occurring solutes can extend the temperature windows for activity of microorganisms. We found that substances known to disorder cellular macromolecules (chaotropes) did expand microbial growth windows, fungi preferentially accumulated chaotropic metabolites at low temperature, and chemical activities of solutes determined microbial survival at extremes of temperature as well as pressure. This information can enhance the precision of models used to predict if extraterrestrial and other hostile environments are able to support life; furthermore, chaotropes may be used to extend the growth windows for key microbes, such as saprotrophs, in cold ecosystems and man-made biomes.
微生物细胞，最终是地球的生物圈，在狭窄的物理化学条件范围内发挥作用。对于大多数生态系统来说，生产力是受低温限制的，而微生物则是限制因素。本研究旨在确定天然存在的溶质是否可以扩大微生物活性的温度窗口。我们发现，已知会扰乱细胞大分子的物质（离液剂）确实扩大了微生物生长窗口，真菌优先在低温下积累离液代谢物，溶质的化学活性决定了微生物在温度和压力极端条件下的生存能力。这些信息可以提高用于预测外星和其他恶劣环境是否能够支持生命的模型的精度；此外，离液剂可以用于扩大寒冷生态系统和人为生物群落中关键微生物（如腐生生物）的生长窗口。
