Section – 3
April 15, 2013
Microorganisms are constantly finding ways to resists to antibiotics. For this reason, it is important to test and observe unknown organisms in the lab to continually improve the health and well being of society. The objective of this report was to first isolate a single colony of an unknown culture on a LB agar plate. From here, a slant was made and used for multiple types of testing in order to determine the identity of the unknown organism. The tests performed to identify the unknown organism included Gram Staining, Fluid thioglycollate/aero-tolerance test, Methyl Red-Vogues Proskauer, SIM test, Lysine Decarboxylase test, Lactose Fermentation test, Simmons Citrate test, and TSI test. The Gram staining technique showed that the organism was Gram negative and bacilli shaped. The fluid thioglycollate test showed that the organism was a facultative anaerobe, meaning ATP can be produced through aerobic respiration or fermentation. Positive results for the remaining tests included Vogues Proskauer test, Lysine Decarboxylase test, Simmons Citrate test, and the motility portion of the SIM test. Negative results included Methyl Red test, Lactose Fermentation test, and the indole and sulfur portion of the SIM test. The TSI test showed a yellow butt and slant, with bubbles and no black precipitate. These conclusions identified the unknown organism as Serratia marcescens.
The purpose of this paper was to inform the reader of the importance of microbiology in the world today. Microbiology studies the behavior of microorganisms and teaches students about the effect of bacteria, fungi, viruses, algae, and yeast on living things. Studying these microorganisms gives insight to the spread of different diseases and how they can be controlled, treated, and prevented through antibiotics, antimicrobics, and vaccinations. These microorganisms also play a factor in agriculture and food production, and even food contamination. Additionally, waste management and mineral extractions are connected to microbial strains. Without the observations of several important men, the waste management, food industry, mining, medicine, and all other research would not be where it is today. There is not clear evidence as to who made the first observation of microorganisms, but in the 1600s, a man named Robert Hooke was said to make important observations of different strands of fungi. Another important contributor to the microbiology world was Anton van Leeuwenhoek. From 1670 to 1723, he observed accurate images of protozoa, fungi, and bacteria. After his death in 1723, many years went by with little improvement towards the development of microbiology, and the theory of spontaneous generation developed. However, Francesco Redi eventually disproved this belief along with Lazzaro Spallanzani who each stated that decaying meat and boiled broth would not give rise to microscopic organisms. Lastly, a scientist by the name of Louis Pasteur attempted to prove his theory that bacteria were to blame for products like wine and dairy becoming sour. After many unsuccessful attempts to prove his germ theory, Robert Koch proved this theory by refining anthrax bacteria apart from all other organisms. These discoveries and observations about new microorganisms is important in our world, because it led to new advances and cures of existing and future diseases. It allowed us to quickly respond to different strains of diseases and prevent many deaths and illnesses.
In order to identify an unknown organism, it first was isolated from the sample. This process was completed using aseptic technique in order to prevent contamination that would skew the results. Once the bacteria was cultured in the lab, the different tests listed above were...
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