
Thermophilic bacteria can thrive in extreme heat because their proteins have an abundance of disulfides (yellow, above), covalent bonds between sulfur atoms that improve stability and likely boost heat-tolerance. (Yeates et al.)Warm-blooded creatures maintain a relatively stable body temperature that cannot tolerate the stress of intense heat (or cold). When it's too hot proteins destabilize and degrade--in some cases, with fatal results. But some bacterial and archaeal organisms appear to defy nature (as we think of it) by flourishing in extremely high temperatures. The archaeal microbe Pyrobaculum aerophilum, for example--originally found in a boiling marine water hole in Italy--thrives at ~100 °C (212 °C).

