Very few environments are exposed to just one physical or chemical extreme. Most natural environments, from the interior of volcanoes to the interior of the human body, expose microorganisms to multiple extremes. Yet we know very little about how organisms adapt to multiple stresses, whether these stresses are synergistic or antagonistic and when they are defined by energetic limitations of the cell of physical limits.
In this project, we will use both laboratory and theoretical approaches to investigate the limits of life at extremes and in particular to study the physiological and biochemical response of microbes to individual and combined multiple extremes such as pH, temperature, salts and others. We will investigate whether the lack of isolated organisms at certain combined stresses reflects a sampling bias or a fundamental physical or energetic barrier to adaptation to these extremes. Modelling will be focused on understanding how we can more accurately predict the interaction of different extremes in determining microbial survival and growth.
As well as informing a general understanding of how life adapts to extremes, this work has diverse implications, for example for understanding how microbial life adapts to combined extremes within the human body as pathogens and whether it could potentially evolve in the multiple extremes of extraterrestrial environments.
 Harrison JP, Dobinson L, Freeman K, McKenzie, R, Wyllie D, Nixon, SL, Cockell CS. 2015. Aerobically respiring prokaryotic strains exhibit a broader temperature–pH– salinity space for cell division than anaerobically respiring and fermentative strains. J. R. Soc. Interface 12: 20150658
 Harrison JP, Hallsworth JE, Cockell CS. 2015. Reduction of the temperature sensitivity of Halomonas hydrothermalis by iron starvation combined with microaerobic conditions. Applied Environ Microbiology 81, 2156-2162.
 Harrison JP, Gheeraert N, Tsigelnitskiy D, Cockell CS. 2013. The limits for life under multiple extremes. Trends in Microbiology 21, 204-212.
The project supervisors welcome informal enquiries about this project.
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