What are the physical and chemical limits of life? After all, some microbes are happy to live at temperatures that boil water. Molecular biologist Hiromi Kagawa studies extremophiles, organisms that live in what we consider to be very unusual conditions, such as extreme heat or cold, environments that are very dry, are highly acidic, or are subject to massive amounts of radiation. The hardy organisms that can manage to thrive in such conditions could give us essential clues to how life might cope with tough environments on other worlds, and possibly how we might co-opt some of these survival strategies for protecting ourselves during space flight to other planets.
In particular, Hiromi is studying an extremophile microbe known as Sulfolobus shibatae, originally isolated from an acidic hot spring in Japan. Its acid-resistant envelope and powerful proton pump keep the interior of this diminutive life form at a neutral pH even in extremely acidic, near-boiling environments. Its biomolecules, including lipids and proteins, are naturally heat stable or stabilized by some still-mysterious mechanism, and understanding the latter is one of the goals of Hiromi’s research.
Extreme environments on Earth might be normal environments in the cosmos. By studying the coping mechanisms of the life that can survive in such hostile habitats, we could be studying aliens on Earth.