Microbiology

Microbiology Study Guide

subsequently immune from re-infection, variolation , which is an induction of a mild form of the disease. This involved the inhalation and sniffing of dried crusts from a smallpox lesion. Later this practice changed to inoculation through the use of the pus from a lesion scratched into the skin. In 1796 after hearing from a milkmaid that she could not contract smallpox because she had already had cowpox, Edward Jenner took scrapings from cowpox lesions then used these scrapings when scratching the arm of a young child. A small bump appeared in a few days, followed by the mild illness of cowpox. He then directly exposed that same boy to smallpox, with the result of no smallpox disease development, thus confirming vaccination. Discovery of Viruses The very first virus discovered is credited to the St. Petersburg Academy of Science in 1892 by Dmitri Iwanowsk (1864-1920), a Russian botanist. While studying mosaic tobacco disease, he found that the agent causing the disease was small enough to pass through a ceramic filter small enough to trap bacteria. This is generally accepted as the beginning of virology. During the 1940s the electron microscope was invented, which allowed microbiologists a more in-depth observation of viruses. Development of Chemotherapeutic Agents (Chemicals, Medications, and Drugs) Once microbiologists were knowledgeable on the relationship between microbes and disease, scientists wanted to find substances to destroy the microbes that caused disease. Chemotherapy is the treatment of diseases with the use of chemical substances. Antibiotics and synthetic drugs are chemotherapy agents. Antibiotics are derived from naturally existing bacteria and fungi, while synthetic drugs are developed as chemicals in a laboratory. The first chemotherapy drugs were quinine, a bark extract used to treat malaria and salvarsan, and were developed in 1910 by Paul Ehrlich. Salvarsan contained arsenic and was used to treat syphilis. 1.2 Naming and Classifying Microorganisms Nomenclature The system of nomenclature (naming) for organisms used today was established in 1735 by Carlos Linnaeus. Scientific names are in Latin. Scientific nomenclature assigns two names: the Genus is the first name and is always capitalized; the specific epithet (species) is the second name and is not capitalized. The organism is referred to by both names and is always underlined or italicized . Once the scientific name has been mentioned completely, it can then be abbreviated with the initial of the first name followed by the second name. Scientific names can describe an organism, honor a researcher, or identify the habitat of a species. For example, Staphylococcus aurens is the scientific name for a bacterium found on skin. Staphylo describes the clustered arrangement of cells; coccus means that they are shaped like spheres. The specific epithet (second name), aurens is Latin for golden, which is the color of many colonies of these prevention was undertaken through the practice of

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