rbradbur@oracle.UUCP (Robert Bradbury) (02/18/88)
The Feb 13 issue of Science News has a very interesting article about life forms (nematodes, brine shrimp, tardigrades) which can "live" after "death" by dehydration. The gist of the article is that these animals have evolved a bio-chemistry which allows them to be de-hydrated to the point that metabolism *may* cease. They can be re-hydrated after 5 to 120 years and return to "life". The survival rates for 5 year dehydration of nematodes is 80-90%. The bio-chemistry seems to be fairly simple in that high concentrations of trehalose (a two glucose ring sugar) keep lipids (in cell walls) from breaking down and trehalose in combination with zinc protects proteins and enzymes. The sugar prevents damage when the water is removed by "locking" the lipids and proteins in their "hydrated" shape. They can then be re-hydrated without much damage. This leads to some interesting questions: - If metabolism stops in de-hydrated life forms have they "died"? One of the researchers (John Crowe - UC Davis) proposes that the definition for "life" might have to be simply "organized structure". If that is true then are mineral crystals or computer chips alive? - If the survival rates of these animals is so high are efforts to preserve organs/human beings by freezing somewhat misdirected? Shouldn't the process be to bathe the tissues in a trehalose and zinc solution, de-hydrate and then freeze? I'm a fairly strong believer that science is going to eventually solve the freezing/re-animation problem and would be interested in views on that impact on society (insurance, wills, religion, etc). (We might want to move such things to a more appropriate group though.) -- Robert Bradbury Oracle Corporation (206) 784-9726 hplabs!oracle!rbradbur
akkana%brain@sdcsvax.ucsd.edu (Akkana) (02/25/88)
In article <245@oracle.UUCP>, rbradbur@oracle.UUCP (Robert Bradbury) writes: > The Feb 13 issue of Science News has a very interesting article about > life forms (nematodes, brine shrimp, tardigrades) which can "live" > after "death" by dehydration. The gist of the article is that Did you ever buy "Sea Monkeys" when you were a kid? :-) (For those who didn't, they were little packets of dried brine shrimp which turned into breeding colonies of live wiggling brine shrimp when you dumped them into water. Neat stuff. The literature which came with them wasn't very scientific, though -- it was all about "Bringing you the MIRACLE of INSTANT LIFE!" and that sort of thing ...) .. ...Akkana LaboratoryForBiologicalDynamicsAndTheoreticalMedicine, UCSD akkana%brain@ucsd.edu ihnp4!lanl!brain.ucsd.edu!akkana "I think I'll take a walk. Hmm, wonder where this wire goes?" -- Max Headroom