Monday, September 16, 2019
Bacteria
Bacteria ? small prokaryotic microorganisms that can be found everywhere ? can cause disease. This may seem like basic knowledge today, but it was not in the past. In the 19th century, the spread of disease was believed to be either inherited, due to lifestyle choices, or a result of environmental factors; water and air-borne infections were not generally accepted, which was, in reality, the cause of a significant amount of diseases during that time period. In addition, their treatments were largely based on the change of location to an area with cleaner air along with the removal of the disease through blood, vomit, and feces. (Marsh, 2016) These beliefs started to disappear when scientists and physicians such as Robert Koch began to undergo breakthroughs. Koch had a significant number of discoveries that helped create and develop what we now call bacteriology such as discovering the bacteria responsible for anthrax, tuberculosis, and cholera. (Nobel Media AB, 2014) In fact, he is even considered the father of bacteriology. Without the research conducted and discoveries made by Robert Koch, the field of bacteriology would not be nearly as advanced and evolved as it is today. Robert Koch, born on December 11, 1843 in Clausthal, Germany, showed great intelligence throughout his life, even during its first few years; he taught himself to read by the age of five through newspapers and showed interest in biology in high school, foreshadowing the significant contributions he would go on to make in the field. (Nobel Media AB, 2014) Koch attended the University of GÃ ¶ttingen to study medicine during which he was influenced by the view of his anatomy professor, Jacob Henle, that infectious diseases were caused by living parasitic organisms which was published in 1840. (Nobel Media AB, 2014) This led to him developing a strong interest in pathology and infectious diseases as a medical student. (Famous Scientists, n.d.) Following him receiving his M.D. in 1866, Koch went to Berlin to study chemistry under Virchow and then worked in the General Hospital at Hamburg in general practice. (Nobel Media AB, 2014) Later on, he settled in the Province of Posen where he passed the District Medical Officer's Examination. (Nobel Media AB, 2014) After serving as a field surgeon in the Franco-Prussian War in 1870, he served as the District Medical Officer in Wollstein from 1872 to 1880. (Nobel Media AB, 2014) As the District Medical Officer, he built a small laboratory that contained a microscope, a microtome, and a homemade incubator in which he began his study of algae and then pathogenic organisms. (Stevenson, 1998) The beliefs of the early 19th century, such as those mentioned previously, were all about to change. The germ theory was being developed by Louis Pasteur (Brought to Life, n.d.) who had shifted from studying fermentation to studying disease. (Ullmann, n.d.) However, the role of bacteria in contagious disease was uncertain, which is where Koch decided to begin his research. (Brought to Life, n.d.) Robert Koch made significant discoveries regarding the cause of three diseases that were prevalent at the time: anthrax, tuberculosis, and cholera. His study of anthrax began when he noticed many of the farm animals in the Wollstein district, where he worked, were being infected by anthrax. (Nobel Media AB, 2014) The bacteria Bacillus anthracis had already been discovered, but Koch scientifically proved it was the cause of anthrax. (Nobel Media AB, 2014) He did this by infecting mice with the bacteria and observing it had contracted anthrax and had even passed it to other mice (Brought to Life, n.d.) In addition, while studying anthrax, Koch discovered the anthrax life cycle by growing cultures on an ox eye. The life cycle showed how the bacteria can turn into spores that can survive harsh conditions and then redevelop into the disease-causing bacteria years later. (Stevenson, 1998) Along with the anthrax research, Koch discovered the tubercle bacillus responsible for causing tuberculosis, Mycobacterium tuberculosis, and the method for growing pure cultures of it. (Nobel Media AB, 2014) He did this by developing and altering his method of staining to find a more efficient way to view samples. (Stevenson, 1998) The last disease Koch studied was cholera, and he discovered the vibrio that causes the disease, Vibrio cholerae, in Egypt where he was sent to observe the outbreak of the disease. (Nobel Media AB, 2014) The discovery of these bacteria had an immense impact on the medical field. First, the discovery of the cause for anthrax, tuberculosis, and cholera led to the development of their vaccines, for had scientists not known for sure what caused those diseases, they would not have been able to develop the preventative measures. Also, Koch's work and research with anthrax produced the first definite piece of proof of the causal relationship between a specific microorganism and a specific disease, providing the basis of Koch's postulates. (Stevenson, 1998) He developed Koch's postulates which are four standards that must be met in order to determine the cause of an infectious disease ? another way he impacted the medical field. (Famous Scientists, n.d.) It was very useful because it was, and still is, a universal method for testing whether a specific bacterium causes a particular disease which also helped him discover the cause behind tuberculosis. (Hodkinson, 2015) It was for his work with tuberculosis that Robert Koch received a Nobel prize in 1905 in physiology or medicine. (Brought to Life, n.d.) This research conducted by Koch successfully provided proof for the germ theory, strengthening the understanding of disease. Without the work done by Koch to determine the bacteria that cause these diseases, many deadly diseases may have still been around decades after they should have been eradicated, for it was largely due to him that other scientists went on to figure out the causes of various other diseases.(Brought to Life, n.d.) While finding and determining the cause of these diseases, Robert Koch discovered more efficient methods for viewing bacteria. One of the methods is the process of heat fixing. In his paper published in 1877, Koch described his technique of preparing a thin layer of bacteria on a glass slide and fixing them by passing the slide over a flame, exposing it to gentle heat. (Stevenson, 1998) Moreover, Koch and his team developed methods of staining bacteria to improve its visibility under a microscope. (Brought to Life, n.d.) Along with that, he created a solid substance on which to grow bacteria. He reached the final product by first evaluating coagulated egg albumen, starch paste, and a clean slice of potato and then deciding on a broth solidified using gelatin or agar. (Nobel Media AB, 2014) These procedures greatly impacted bacteriology, providing scientists with more efficient ways to carefully study bacteria under a microscope and in the pure form. The processes of heat fixing and staining allowed Koch himself to discover the tubercle bacillus and have enabled scientists after that to make remarkable breakthroughs and discoveries. The creation of the solid medium using gelatin was an extraordinary achievement; it made it possible to isolate bacterial colonies. This was crucial during the research conducted, for pure cultures were necessary in order to isolate the bacteria and definitively carry out experiments. The development of all these procedures assisted Koch himself in his discoveries along with other scientists and physicians later on. Robert Koch, with the help of methods he developed including heat fixing, staining, and isolating colonies on a hard medium, successfully determined and proved the bacteria that cause anthrax, tuberculosis, and cholera. All the discoveries and achievements have had a great impact in medicine, especially in bacteriology which is what it is today due to the work of Robert Koch.
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