A diverse collection of microorganisms co-exist with life on Earth; most of them as inhabitants among plants or oceans, many as normal flora in humans, and some in remote locations in the most extreme habitats. Despite being ubiquitous in nature and typically harmless, bacteria get particular attention for causing disease in humans.
Correct identification of a microorganism allows for proper investigation of a particular species, and prevention or treatment of a disease if necessary. During lab, students were instructed to choose a test tube inoculated with an unknown organism and then prompted to initiate a series of appropriate lab tests to correctly identify the organism.
RESULTS
Unknown 3 was received in Trypticase Soy Broth. A Gram test was immediately performed to reveal that the bacterium was a Gram positive cocci. Once the morphology and Gram stain were determined and the presence of growth on a Trypticase Soy Agar slant was apparent, two tests were used to narrow down the list of possible organisms; those tests were the Methyl Red test and Urea hydrolysis.
The Methyl Red test is used to distinguish an organism’s ability to ferment mixed acid, which is verified by the change in color of the Methyl Red broth after a reagent is added. There was no change in color of the broth which indicated a negative result. Unknown 3 was also inoculated in a Urease broth, which tested for the presence of Urease, an enzyme responsible for hydrolyzing Urea into ammonia and carbon dioxide. If Urea had metabolized, indicating a positive test, the broth would have turned pink. The test was negative. The figures below provide a summary and supplement the analysis; Figure 1 describes the purpose of the test, the results and its implicatio...
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...s culminates in the identification of the organism Micrococcus roseus.
REFERENCES
1. LeBeoffe, Michael J. (2012). Brief Microbiology Laboratory Theory and Application. 2nd Edition. Englewood, Colorado: Morton Publishing Company.
2. Nester, Eugene. (2012). The Diversity of Prokaryotic Organism. Microbiology: A Human Perspective. 7th Edition (pp. 264, 275). New York, NY: McGraw-Hill.
3. Todar, Kenneth. (2012). Staphylococcus. Retrieved from http://textbookofbacteriology.net/staph.html
4. Tortora, Gerard, B. Funke & C. Case. (2010). Interaction Between Microbe and Host: Normal Microbiota. Microbiology: An Introduction. 10th Edition. (pp. 401 -403). San Francisco, CA: Pearson Education, Inc.
5. Wistreich, George. (2007). Microbiology Perspectives: A Photographic Survey of the Microbial World. 2nd Ed. Upper Saddle River, New Jersey: Pearson Education, Inc.
The isolate possesses some enzymes required for hydrolytic reactions. Hydrolytic enzymes found to be secreted from the bacterium, are -amylase, casein, and PYRase. In the starch hydrolysis and casein tests, there was a zone of clearing around the bacterium, which was indicative of the secreted enzymes necessary to break down starch and casein. In the PYR test, the presence of PYRase was detected by a color change to red on the PYR disc after the addition of the PYR reagent (p-dimethylaminocinnamaldehyde). Hydrolytic enzymes for which the EI tested negative were urease, gelatinase, and DNAse. In the Urea Hydrolysis test, it was observed that the urea broth did not have a color change, indicating that there was no urease secreted to break down urea in the broth. Similarly, there was no gelatinase present to break down gelatin in the Gelatin Hydrolysis test, so the nutrient gelatin remained solid. It was concluded that the EI does not possess DNase because there was no clearing zone around the bacteria, indicating that DNA had not been
The first day an unknown sample was assigned to each group of students. The first test applied was a gram stain to test for gram positive or gram-negative bacteria. The morphology of the two types of bacteria was viewed under the microscope and recorded. Then the sample was put on agar plates using the quadrant streak method for isolation. There were three agar plates; one was incubated at room temperature, the second at 30 degrees Celsius, and the third at 37 degrees Celsius. By placing each plate at a different temperature optimal growth temperature can be predicted for both species of bacteria.
In this lab project, the microbiology students were given 2 unknown bacteria in a mixed broth each broth being numbered. The goal of this project is to determine the species of bacteria in the broth. They had to separate and isolate the bacteria from the mixed broth and ran numerous tests to identify the unknown bacteria. The significance of identifying an unknown bacteria is in a clinical setting. Determining the exact bacteria in order to prescribe the right treatment for the patient. This project is significant for a microbiology students because it gives necessary skills to them for future careers relating to clinical and research work.
They can be found anywhere and identifying them becomes crucial to understanding their characteristics and their effects on other living things, especially humans. Biochemical testing helps us identify the microorganism present with great accuracy. The tests used in this experiment are rudimentary but are fundamental starting points for tests used in medical labs and helps students attain a better understanding of how tests are conducted in a real lab setting. The first step in this process is to use gram-staining technique to narrow down the unknown bacteria into one of the two big domains; gram-negative and gram-positive. Once the gram type is identified, biochemical tests are conducted to narrow down the specific bacterial species.
After the end of the experiment the unknown 10 sample was Staphylococcus epidermidis. Came to this conclusion by first beginning with a Gram Stain test. By doing this test it would be easier to determine which route to take on the man made flow chart. Gram positive and gram negative bacteria have a set of different tests to help determine the unknown bacterium. Based on the different tests that were conducted in lab during the semester it was determined that the blood agar, MSA, and catalase test are used for gram positive bacteria while Macconkey, EMB, TSI, and citrate tests are used for gram negative bacteria. The results of the gram stain test were cocci and purple. This indicated that the unknown bacteria were gram positive. The gram stain test eliminated Escherichia coli, Klebsiella pneumonia, Salmonella enterica, and Yersinia enterocolitica as choices because these bacteria are gram negative. Next a Blood Agar plate was used because in order to do a MSA or a Catalase test there needs to be a colony of the bacteria. The result of the Blood Agar plate was nonhemolytic. This indicated that there was no lysis of red blood cells. By looking at the plate there was no change in the medium. Next an MSA test was done and the results showed that there was growth but no color change. This illustrates that the unkown bacteria could tolerate high salt concentration but not ferment mannitol. The MSA plate eliminated Streptococcus pneumonia and Streptococcus pyogenes as choices since the bacteria can’t grow in high salt concentration. Staphylococcus aureus could be eliminated because not only did the unknown bacteria grow but also it didn’t change color to yellow. Lastly a Catalase test was done by taking a colony from the Blood Agar plate...
I also inoculated a tryptic soy broth (TSB), a nutrient gelatin deep, a motility agar deep, a fluid thioglycollate medium (FTM) tube, and a TSA plate with my unknown culture. All of these inoculated media were incubated until the next class period (about 48 hours). Then when I came to class most of my inoculated tubes and my streak plate appeared to have growth. The next step I took was making a gram stain to determine the gram reaction and cellular morphology of my unknown. I used my working slant to do this, after careful examination of the gram stain, I learned that my unknown was a gram-positive bacterium. I then preceded by making a negative stain to see the size of the cells of my unknown bacteria. The cell shape was cocci and the cells occurred in clusters of tetrads. After discovering that my unknown bacteria was gram-positive cocci, I turned to page 207 of the lab manual to narrow down my options, there was only four out of the gram-positive list that were
Jennifer Ackerman's main focus in her article The Ultimate Social Network, is that of the functions concerning bacteria within humans. Although scientists have had presumptions about humans being proficient in governing their body’s innermost structure, they soon come to recognize the sophistication of our inner space which holds an extensive plethora of bacteria and other microorganisms that lie within each and every one of us. Moreover, scientists' new and emerging view of how the human body operates, and the cause of increasing present-day diseases (i.e. obesity and different autoimmune disorders) are uncovered by analyzing effects of certain microbe species in our bodies. By italicizing on points such as the above, in conjunction with bacteria's genetic variations, and modern computing technology, the author proves that scientists are quickly progressing with the characterization the most prevalent species of microbes, which, in her opinion, is definitely paying off.
Bacteria play a large role in our health, the environment, and most aspects of life. They can be used in beneficial ways, such as decomposing wastes, enhancing fertilizer for crops, and breaking down of substances that our bodies cannot. However, many bacteria can also be very harmful by causing disease. Understanding how to identify bacteria has numerous applications and is incredibly important for anyone planning to enter the medical field or begin a career in research. Having the background knowledge of identifying an unknown bacteria may one day aid healthcare professionals diagnose their patient with a particular bacterial infection or help researchers determine various clinical, agricultural, and numerous other uses for bacteria.
Linton, Alan. 1982. Microbes, Man and Animals: The Natural History of Microbial Interactions. John Wiley & Sons. 342pp
I identified the genus and species of an unknown bacterial culture, #16, and I applied the following knowledge of morphologic, cultural and metabolic characteristics of the unknown microorganism according to the laboratory manual as well as my class notes and power point print outs. I was given an incubated agar slant labeled #16 and a rack of different tests to either examine or perform myself; the tests are as follows: Gram Stain; Nutrient Gelatin Test; Carbohydrate Fermentation; Dextrose, Lactose and Sucrose; IMVIC tests; Citrate, Indole, Mythel-Red and Vogues Proskauer test; as well as a Urease and TSI Test. Materials and Methods/Results Upon receiving the Microorganism (M.O.) #16, I prepared a slide by cleaning and drying it. Then, using a bottle of water I placed a sterile drop of water on the slide and used an inoculating loop, flame sterilized, I took a small sample of the unknown growth in my agar slant and smeared it onto the slide in a dime sized circle and then heat fixed it for ten minutes.
...standing the nature of relationship between the residing microbes inside human cells and about their function is very important to put an end to this war and to live in peace with the natural organisms that are benefitting human body and their survival has become our primary importance.
Microbes are everywhere in the biosphere, and their presence invariably affects the environment in which they grow. The effects
Leboffe, M. J., & Pierce, B. E. (2010). Microbiology: Laboratory Theory and Application, Third Edition 3rd Edition (3rd Ed.). Morton Publishing
When you hear the word bacteria the first thing that might come to mind would be a germ. Although there can be many harmful types of bacteria, it is an essential part of life. Bacterium is all over...
The human microbiome is the collective ensemble of a wide diversity and density of living micro organisms found both in and on the human body (i.e. the collective genome of the human microbiota). Its relevance has become so important as of late that is has taken its place at the top of 21st century scientific discoveries. (Ash 2014) It consists of mostly bacteria but also includes some archaea, fungi, viruses and protozoa. The main microbiome communities active in the body reside on and in deep layers of skin, the oral cavity,the nasal cavity, the urogenital tract and in the gastrointestinal tracts. (Blaser 2010)