Word: bacterium
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Dates: during 1970-1979
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What worries many of the townspeople is Harvard's intention to learn more about DNA, the master molecule of heredity, by inserting segments of DNA from other organisms into E. coli, a common intestinal bacterium often used in genetic research. Some scientists fear that fusion of these DNA segments with E. coli's DNA might create new, lethal microbes against which humans have no immunity. To guard against this and other possible threats, the National Institutes of Health recently issued tough rules to govern such research...
...experiments, which involve transferring DNA into specimens of E coli, a commonly used bacterium, are designed to produce a new species, whose characteristics will be unknown and possibly dangerous...
NITROGEN FIXATION. At present only legumes such as peas, beans and alfalfa-with the aid of a soil-dwelling bacterium called rhizobium-are known to be naturally capable of fixing nitrogen from the air-joining it to other substances to form compounds necessary for plant growth. Most other plants must obtain their nitrogen from natural and man-made fertilizers. But scientists are seeking to give more plants this nitrogen-fixing ability. At Utah's Brigham Young University, biologists are attempting to "infect" other species of plants with rhizobia. Scientists in England have isolated the segment of the rhizobial...
Healthy Appetite. Chakrabarty first determined that the genes for oil-degrading enzymes were carried not on the microbes' chromosomes, where most genetic material is found, but elsewhere in the cell. He discovered that although the "plasmids," as these genes are called, were isolated and transferred from one bacterium to another easily enough, the two batteries of genes he tested would not stay together in the same cell; nor could cells of different strains be paired. When they were, the bacteria competed with and inhibited each other...
...practical; spruce and balsam are best adapted to the north woods and, says Fred Holt, director of Maine's bureau of forestry, "they always come back when you plant something else." Biological controls-most notably one that involves spraying the foliage with a solution containing Bacillus thuringiensus, a bacterium that kills only caterpillars-are still too expensive and difficult to apply over a wide area...