The Development of Microbiology This

This chapter gives the history of the development of microbiology as a science, and names the pioneers in the field and their discoveries. An English scientist, Robert Hooke, published a book called ôMicrographie in 1665 on chemistry and the microscope. The real impetus came from Anton van Leeuwenhoek, a Dutch haberdasher who ground lenses in his spare time, and was the first to observe things under the microscope. He described his findings on examining blood cells, sperm, and tiny insects, and found what he called ôanimalculesö in water from a marsh.

Until the 1800s, scientists believed that disease was caused by what they termed ômiasmaö - an altered chemical quality of the atmosphere caused by decaying and diseased bodies. It had been thought since the days of Aristotle that small animals arose on decaying matter by spontaneous generation. Woven into this theory was that of Girolamo Fracostoro, who believed disease was caused by infection passed among individuals. In the mid 1600s, Athanasius Kircher reported seeing little worms in the blood of plague victims, but was largely ignored. In the 1670s, Francesco Redi first put forward the theory that flies had reproductive organs and laid eggs on meat. He tested the theory by putting meat in enclosed jars and some in open jars to prove his point. John Needham, a British cleric, repeated the experiment, and managed to grow microorganisms in sealed flasks, thus supporting t

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nce; transposons are larger than insertion sequences, but similarly interrupt the coding sequences. Base triplets can code for more than one amino acid so mutations can affect the production of more than one protein. Most agents which cause mutations cause cancer in humans so the Ames test was developed. If an agent can induce mutations in bacteria, it can cause cancer in humans. In transformation, donor cells break apart and release fragments of DNA. Transformation only occurs between cells of the same species. A fragment of double stranded DNA passes into a recipient cell, where an enzyme degrades one strand of the DNA and the other is incorporated into the cellsÆ own DNA. During conjugation, two bacterial cells come together and the donor transfers DNA to the recipient. Conjugation occurs between Escherichia and Shigella, Salmonella and Serratia, and Escherichia and Salmonella, and is known as intergenic transfer. It has significance because it transfers antibiotic resistance genes on plasmids. Transduction is a process whereby bacterial DNA is altered by a bacteriophage. It can be done in two ways. In generalized transduction, bacteriophages invade a bacterium and while replicating inside it, they produce a long
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Some common words found in the essay are:
Bacterial Diseases, Principles Chemistry, STD Gonorrhea, Diseases Bacillus, Salmonella Shigellosis, Diseases Intoxications, Bacterial DNA, Escherichia Salmonella, Metabolism Bacteria, Tobramycin Pseudomonas, amino acids, food poisoning, bacterial dna, protein synthesis, caused rickettsia, staphylococcus aureus, amino acid, typhoid fever, blood cells, food water, red blood cells, chlamydia trachomatis causes, amino acid chains, caused spirochete borrelia, 20 amino acids,
Approximate Word count = 6790
Approximate Pages = 27 (250 words per page)