I. Purpose The purpose of the study is to identify an unknown microorganism using multiple microbiology lab techniques. Through this process I will gain knowledge on how to perform these techniques as well as the importance of these tests on identifying unknown microorganisms. This is significant as the goal of this course is to familiarize ourselves with the common microbiology tests as well as the microorganisms we encounter in our daily activities. II. Materials Media: TSA TSB Thioglycolate Motility Gel Agar Simmon’s citrate agar Nutrient broth MR-VP broth Nitrate broth Starch Agar plate Skim milk agar plate Urea slant Phenylalanine agar SIM Spirit Blue Agar Dnase Agar Nutrient Gelatin Mineral Oil Carbohydrate …show more content…
To perform this test we first did a Gram stain on our organism to determine if it was gram-positive or gram-negative. After this we performed a mixed Gram stain by incorporating our organism with a known bacteria that stained opposite of unknown. We were given the size of the known bacteria and performed a comparative analysis under the microscope to determine the size of our unknown. In my case the control was a gram-negative bacteria Escherichia coli. Acid-fast Stain: The Acid-fast stain is used to determine whether are unknown contains a high amount of mycolic acid in its cell wall. Those organisms that are acid fast will retain the basic fuschin stain while those who are not will have this stain washed away by ethanol and subsequently stained blue with methyl blue in the final step of this stain. The details of this procedure are listed in Brown, Microbiological Applications p. 115. Spore Stain: The spore stain is used to determine if the unknown organism produces endospores as way of protecting itself. This stain is useful for detecting bacteria in the genus Bacillus and Clostridia. The endospores are highly resistance to staining a simple stain is not usual in visualizing them. Heat must be used as a mordant to drive in the malachite green stain. The endospore will then appear green. The details of this procedure are listed in Brown, Microbiological Applications p.
One bacterium was gram negative. It underwent four different tests. These tests were the EMB test (Eosin Mehylene Blue), the Sulfur Indole Motility (SIM) test, the Urease test, and the Simmon’s Citrate Utilization test. The EMB test checks for a bacteria’s ability to ferment lactose. This test is accomplished by placing the bacteria on Eosin Methylene Blue agar. The agar is selective for gram negative bacteria and those bacteria that can ferment lactose will have colored growth, usually a metallic green sheen.
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.
The purpose of this project was to identify unknown bacteria species from a mixed culture. The two unknown species were initially plated onto Tryptic Soy Agar (TSA), Eosin Methylene Blue (EMB), Mannitol Salt Agar (MSA), and blood agar plates to distinguish between the two different bacteria using colony size, color, shape, and growth characteristics. By identifying and inoculating the differing types of colonies, the two unknown bacteria were purified and able to be tested
The name to this lab is identification of unknown species. To know the species from unknown culture, our instructor handover test tube labeled with different number to all students each student with different number. I got test tube labeled #15 culture, which was assigned our instructor. We need to use different media and reagents to work safely and correctly. Before started to working we need to know how to do Gram Stain technique and biochemical testing to determine the name of the unknown species. We used 18 media with 15 reagents, to determine unknown species, which was provided by the Eastfield Dallas community College’s science department. All the methods to determine the “Unknown Lab” were in the book written by Tammy Oliver, Ph.D.
After incubation, we checked the broth for the production gas and a color change from red to yellow which would indicate the presence of an acid. In order to perform a gram stain, we obtained a colony that we had grown on the TSA slant. Then we gathered one test tube containing tryptone broth, one containing citrate slant, and the last two containing MVRP broths. For the MVRP broths, one test tube should be labeled with MR and the next tube should be labeled VP. Next, we inoculated each test tube with the coliforms that we had confirmed as containing negative
The unknown identification laboratory test is made for students to guide themselves into the microbiology laboratory. Students will use the producers, techniques and experiment that they have been used and learned in other pervious classes. During previous laboratory test, many bacteria have been tested and experimented in finding the results of what bacteria was truly growing. There are so many bacteria in our surroundings many of them can be found all around us and in our environment. Some of the bacteria have been tested and are known to help patients when they are sick, they can treat diseases, certain foods, and make antibiotics and many other things. Thought-out this laboratory
In the experiment, five periods are done to accomplish the goal of identification of the unknown microorganism. The first period aims to isolate the genomic DNA from the unknown microorganism using a
In order to preform this experiment you will need; cotton swabs, agar plates, microscope, unused slides, oil immersion, nigrosin, and crystal violet. The first task we must do is use the cotton swabs and swab an item out side of the laboratory, that has the capability of containing either yeast, bacteria, and mold. My lab partners and I chose to swab one of our group members cell phone. Once we swabbed the phone with the cotton swab, we then each had a plate of agar. To start the process of the transfer of the microorganisms you will need to label the agar plates and state where the plate is going to be located after you run your cotton swab over the plate of agar. One group member placed it in the 37C incubator and the others placed it in the cabinet to be stored at room temperature.
The mystery microbe T4 first results were from my gram stain that showed a purple color, rod shape bacteria, that demonstrated the stain was positive. The next test preformed was spore stain, it was positive for spores by taking up on the counterstain that appeared green. The capsule stain was negative the microbes did not have clear halos around them. Next up was the Acid-fast stain that appeared purple/bluish color meaning it was negative.
In the late 1800s, Hans Christian Gram developed the gram staining procedure. Gram staining is a valuable diagnostic tool used in the clinical and research world. The gram stain is a method used to determine the identification of unknown bacteria. (BIO215, 2017)
Most of the results from the science experiments conducted did not occur like they were expected. Most of the results were false negative or false positive due to a human error within preparation of the bacteria slides. For example, the simple stain results for the Corynebacterium xerosis bacteria were inconclusive because they appeared to be very tiny circular dots instead of their usual rod shape. There is a possibility that it could have been the result of overheating the bacteria during the heat fixing process. This also could have been the result of leaving the crystal violet dye on for too long allowing the dye to dry up on the slide. The next example of an experiment’s results gone wrong is apparent in the Gram staining experiment. The
Of course, before we began the experiment, it is crucial for us to perform aseptic technique in order to minimize contamination. In the wake of setting up the smears of the microorganisms, the smears were air dried. Then we stain both smears using crystal violet dyes. Crystal violet dyes are basic dyes that have positively charges particles that helps them to bind to negatively charged particles. The following step is to add iodine to the smear. Next, we washed the iodine with tap water and dried off the excess water. After that, absolute methanol was being added to act as a decolorizing agent. For gram positive bacteria, the addition of alcohol dehydrated the layer of peptidoglycan which thus would trap the CVI complex. This causes the gram positive bacteria to appear to be purple as the CVI complex are being held. The addition of alcohol is not to be over 15 seconds as this would break the cell wall of the bacteria, thus resulting in no stain to be observed. The slides are washed with water and dried off. In the next step, safranin was utilized to counterstain the smear. This is to enable the gram negative bacteria to be visualized easily as it can be stained pink. The gram positive bacteria does not being stained pink when safranin was being introduced because the peptidoglycan layer as of now have CVI complex. At that point, the slides were washed utilizing tap water and dried off.
Gram staining can also be called Gram’s Method because of the biologist it was named
The gram stain reaction of L. interrogans is gram negative. To stain this bacteria you must use a relatively new staining technique termed immunofluorescence which uses a ultraviolet light to identify its staining. You can also use an older technique that is very time consuming, which is silver staining.
A microscopic examination was usually paired with a stain. For example, a Gram stain can be used to identify the shape of the microorganism and the number of peptidoglycan layers it has. The shape can be and type of cell can be used to determine which genera the unknown bacteria could be classified under.