dubois@uwmacc.UUCP (Paul DuBois) (04/19/85)
> The following article appeared in the February issue of "Adhesives > Age", p. 60: > Bacteria Munch on Nylon > Despite man's persistent efforts to create a substance that is imper- > meable to time, the elements, and hungry critters, nature seems to be finding > ways to prevail. > According to a story in the *Atlanta Constitution*, a strain of > bacteria has evolved a taste for the man-made ingredients in nylon, suggesting > that the stubborn substance may now be biodegradable. > The strain of bacteria, called Flavorbacterium spK172, was first > discovered in 1972 in waste streams flowing from factories in Japan. These > bacteria recently have evolved enzymes that allow them to live solely on the > ingredients of the man-made plastics. > Up to now, the man-made chemical components of plastics like nylon -- > chemicals that aren't found in nature -- have been resistant to metaboliza- > tion by bacteria, fungi, or other living things. They have so resisted decay, > in fact, that nondegradable plastics are a major waste control problem, taking > up space in landfills and trash heaps and littering the landscape. > According to Dr. Susumo Ohno, the enzymes' discoverer, the new > developments may be evidence that evolution sometimes occurs with incredible > swiftness, instead of over billions of years. It is only 45 years since > nylon began entering the environment in large amounts. > Panic not, wearers of pantyhose -- scientists have found no evidence > that Flavorbacteria eat finished nylon or plastic products like stockings, > fishing line, credit cards, or plush carpeting . . .yet. Well. Ray Miller posted an article containing a report on a newspaper story (from Pravda). It was quickly and roundly rejected as irrelevant, as Pravda is a newspaper and not a scientific journal. Ok, fine. (Not really, but for the sake of argument.) Now we have a report on a story in the "Atlanta Constitution". Does the same logic apply? --- But let us accept the above article at face value. It is stated that the bacteria recently have evolved enzumes that allow them to matabolize man-made plastics, and that the discoverer of the bacteria feels this may be evidence of rapidly occurring evolution. I guess the real question is whether the enzyme was present in 1972 or not. What does 'recently evolved' mean? 1985? or 1972? If 1972, then nothing has been shown, because one cannot say that the enzyme wasn't present before (or that it was, of course), and in that case the claim falls to the ground. If it CAN be shown, then what sort of evolution does this constitute? For example, is it substantially different than, say, production of a "new" antibody in response to immunization? --- Note that none of this is anti-science. These are questions that ANY scientist ought to think of. -- | Paul DuBois {allegra,ihnp4,seismo}!uwvax!uwmacc!dubois --+-- | "Danger signs, a creeping independence" |
mrh@cybvax0.UUCP (Mike Huybensz) (04/23/85)
In article <947@uwmacc.UUCP> dubois@uwmacc.UUCP (Paul DuBois) writes: > Well. Ray Miller posted an article containing a report on a newspaper > story (from Pravda). It was quickly and roundly rejected as irrelevant, > as Pravda is a newspaper and not a scientific journal. Ok, fine. (Not > really, but for the sake of argument.) Now we have a report on a story > in the "Atlanta Constitution". > > Does the same logic apply? Yup. It isn't necessary to hypothesize evolution of a new enzyme. > But let us accept the above article at face value. It is stated that > the bacteria recently have evolved enzumes that allow them to > matabolize man-made plastics, and that the discoverer of the bacteria > feels this may be evidence of rapidly occurring evolution. Anybody who has studied bacteria much can tell you that new bacteria are a dime a dozen. Alternatively, genes from other bacteria may have been transported by phages into the new ones. > I guess the real question is whether the enzyme was present in 1972 or > not. What does 'recently evolved' mean? 1985? or 1972? If 1972, > then nothing has been shown, because one cannot say that the enzyme > wasn't present before (or that it was, of course), and in that case > the claim falls to the ground. What evidence is there that this bacterium recently evolved. > If it CAN be shown, then what sort of evolution does this constitute? > For example, is it substantially different than, say, production of a > "new" antibody in response to immunization? If this is indeed evolution, it could represent relocation of genome fragments between species by phages, or through sex. Or it could represent repeated alteration of a precurser enzyme to a more efficient form. But this would all be a form of microevolution: changes within a population, rather than speciation. (The question of what composes a bacterial species is a darn good one....) -- Mike Huybensz ...decvax!genrad!mit-eddie!cybvax0!mrh