Dr Mark Roth and his colleagues wondered how it is that some people can enter a state of frozen suspended animation and then recover from it safely, whereas in general such a change of body temperature is deadly.
The scientists now think they may be on the track of an answer, having learned how to perform the same trick reliably with other lifeforms; in this case yeasts and nematode worms. Yeasts and worms, like humans, will normally simply die if they are chilled down past a certain point. But Roth and his colleagues have found that if the little creatures are starved of oxygen before turning on the cold, they will go into suspended animation from which they recover on warming and go on to live normal yeasty or wormy lives.
Roth and his colleagues think that their work might lead to techniques that would let paramedics or doctors “buy time” for severely injured or ill patients by putting them into suspended states.
The orderly progression through the cell division cycle is of paramount importance to all organisms, as improper progression through the cycle could result in defects with grave consequences. Previously, our lab has shown that model eukaryotes such as Saccharomyces cerevisiae, Caenorhabditis elegans, and Danio rerio all retain high viability after prolonged arrest in a state of anoxia-induced suspended animation, implying that in such a state, progression through the cell division cycle is reversibly arrested in an orderly manner. Here, we show that S. cerevisiae (both wild-type and several cold-sensitive strains) and C. elegans embryos exhibit a dramatic decrease in viability that is associated with dysregulation of the cell cycle when exposed to low temperatures. Further, we find that when the yeast or worms are first transitioned into a state of anoxia-induced suspended animation before cold exposure, the associated cold-induced viability defects are largely abrogated. We present evidence that by imposing an anoxia-induced reversible arrest of the cell cycle, the cells are prevented from engaging in aberrant cell cycle events in the cold, thus allowing the organisms to avoid the lethality that would have occurred in a cold, oxygenated environment