Word: bug
(lookup in dictionary)
(lookup stats)
Dates: during 1970-1979
Sort By: most recent first
(reverse)
...test tube the long, slender, infective form of the single-celled parasite Trypanosoma brucei. That feat-accomplished by Hiroyuki Hirumi, a Japanese-born American scientist, and John Doyle, a Scottish colleague-has been the aim of medical scientists for years. In the past, whenever researchers tried to culture the bug, it invariably reverted to a harmless form. Thus they were unable to learn much about the deadly parasite-to say nothing of devising weapons against...
Unfortunately, the defect proved insufficient. Some of the descendants of the new microbe mutated naturally and began manufacturing their own DAP. So Curtiss went a step further and deleted another gene involved in DAP production. These newly designed bugs remained DAPless. But more frustration awaited Curtiss: the mutants managed to survive and multiply even without DAP. How? Dennis Pereira, a graduate student who worked with Curtiss on the project, discovered that they were producing a sticky substance called colanic acid that held them together in the absence of their normal outer coat. By manipulating still another of the microbe...
After a few more genetic refinements, Curtiss had developed what seemed to be a safe research bacterium. But a major problem remained. Even dying E. coli bacteria can conjugate with healthy ones, transferring their possibly dangerous genetic material in the process. Thus an escaped and dying bug might still pose a danger. Again Curtiss worked his genetic magic, this time taking away from the microbe the ability to produce the chemical thymine, which is a component of the bug's own DNA. Without thymine supplied in the lab, the E. coli could not pass its genes on to healthy...
...more perfect-or defective-microbe for recombinant DNA research. But for the time being, genetic engineers have available a tailor-made microbe that cannot survive outside the laboratory and that cannot colonize or even live in the human intestinal tract. Nor is this the only indication that the bug would make a poor pathogen, or disease organism. Curtiss' handmade microbe will not survive in human serum-including that of cancer patients. It is also easily destroyed by common household detergents...
Curtiss named his transmuted bug E. coli x1776-in honor of the Bicentennial. In November 1976, the NIH certified it for use in genetic engineering experiments, removing one of the major obstacles to resuming recombinant DNA research...