Word: bacterias
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Upstaging the Bacteria. Until only 20 years ago, the disease makers that dominated medicine's attention were the bacteria, hulking big microbes (by comparison with viruses) that generally attack by producing systemic poisons rather than by invading the body's cells. Antibiotics have wiped out or brought under control virtually all the major bacterial diseases: tuberculosis, some forms of pneumonia, diphtheria, scarlet fever, typhoid fever, gonorrhea, syphilis and most of the other illnesses that stir memories of Paul de Kruif's heroic Microbe Hunters...
Most of the bacteria studied by Pasteur and his early followers were big enough to be trapped in fine porcelain filters, devised by Pasteur's assistant Charles Chamberland, and to be seen under the 19th century light microscope. It was a temperamental Dutch botanist, Martinus Beijerinck (1851-1931), who found that whatever caused mosaic disease in tobacco plants could slip through the minute pores of these filters. In 1897 he concluded that this infectious, filter-passing fluid was a "filterable virus." The word virus had been loosely used for centuries to denote any "poison" that caused infectious disease...
...Laboratory) and the electron microscopists, a virus can now be defined as an infectious particle that has no metabolism of its own and reproduces itself only by taking over the metabolic processes of the living cell it invades. Viruses are the ultimate parasites. They parasitize everything in nature from bacteria and flowering plants up through invertebrates such as mosquitoes, and the vertebrates from fish, amphibians, reptiles, birds and mammals...
...these is an enzyme that can dissolve part of a cell's outer coating. Presumably, this is what the flu virus uses to open a hole in the cell-factory wall for its nucleic-acid core to slip through. A virus known as T2 bacteriophage (it attacks bacteria) was found to have a tadpole shape; the "tail" is like a coiled spring around a tiny hypodermic needle that stabs the cell wall, and through this the nucleic-acid core is injected. Micrographs show whether viruses are basically cubic or helical in structure. They also reveal that viruses may have...
...made with killed virus: "I don't think you can do better than nature itself does when it gives you the disease." Back at tissue culture after the war, Enders was joined by two research fellows. Drs. Frederick C. Robbins and Thomas Weller. The work was bedeviled by bacteria contaminating the cultures, making them useless before a slow-starting virus multiplied. Virologists began adding antibiotics to their cultures to keep out bacteria; Enders hit upon a particularly successful combination of penicillin and streptomycin. Yet even in uncontaminated cultures, Enders failed to isolate and grow the obstreperous measles virus...