To limit the amount of errors or contamination in any procedure lab safety rules, gloves, and the aseptic technique was strictly enforced throughout the experiment. The first step to identifying the unknown bacterium was the Streak Plate Method. This method is used to isolate a pure culture from a mixed culture. Also, this method included streaking a tryptic soy agar (TSA) plate into four quadrants, and later incubating the plate for 24 hours. The second step performed was the Gram Stain test. The Gram Stain was used to determine whether the unknown bacterium was gram-positive or gram-negative. First, the unknown sample was smeared onto a slide along with a drop of distilled water. Second, the unknown was air dried and was heat fixed. Third, a series of stains/solution such as crystal violet, iodine, ethanol, and Safranin were used to complete the Gram Stain. During this process each stain/solution was left on the emulsion for a limited amount of time. Also between each stain, there was a removal of the previous stain by rinsing the slide clear with distilled water. After the gram stain was completed, the slide was blotted dry with bibulous paper and was placed under the microscope. While under the microscope, a drop of oil …show more content…
The Catalase test was used to determine whether or not the unknown contains Catalase enzymes that would react when hydrogen peroxide was added. If the unknown contained Catalase enzymes then the unknown would bubble/fizz when the hydrogen peroxide was added, and would be recorded as a positive reaction. If the unknown did not contain Catalase enzymes there would be no reaction, and would be recorded as a negative reaction. The procedures for this test included: obtaining a microscope slide with your unknown sample on it and placing 1-2 drops of hydrogen peroxide on it. The results of the Catalase test would be determined that same
Last test, inoculation of phenylalanine agar is used to determine if phenylalanine deaminase oxidizes phenylalanine into phenylpyruvic acid and ammonia. Sixth test, is a Multiple Test Media used to determine the physiological characteristics of unknown #398. First test, Inoculation of Kligler 's Iron agar was used to determine the production of hydrogen sulfide from cysteine and fermentation of glucose and lactose. Last test, inoculation of litmus milk is used to determine the fermentation of lactose, casein, lactalbumin, and
If the catalase enzyme is present in the organism being tested then when in the presence of hydrogen peroxide (H2O2), the enzyme will convert the solution to water and oxygen, this can be observed bubbling of the organism when hydrogen peroxide is added to the test tube. EMB agar is both a selective and differential media; it is selective for gram-negative cells, in that when a gram-positive culture is plated there will be no colonies after incubation because the eosin and methylene dyes prevent the growth of gram-positive organisms, the
Mannitol Salt Agar (MSA) plate, MacConkey agar (MC) plate, Eosin Methylene Blue agar (EMB), and Hektoen Enteric Agar (HEA) (3). The MacConkey agar plate and the Mannitol Salt agar plate are both used in the identification of the unknown. The MC plate is a selective and differential medium. It is considered a selective medium because the bile salts and crystal violet aspect of the medium prevent the growth of gram positive bacteria (3). This medium is differential because of the lactose and neutral red.
In this experiment, we cultivated an unknown specimen containing two microorganisms. The purpose of this experiment was to use a variety of biochemical test previously learned in the lab to identify the unknown bacteria. The identification of unknown bacteria is a major part of microbiology. Microbiologist observe samples such as blood and sputum in the laboratory for the presence of microorganisms. Identifying unknown bacteria is extremely important in clinical settings because it helps physicians find treatment for infections.
A starch agar plate was inoculated with a streak of the unknown bacteria and then incubated. On the second day of incubation, the plate was removed from the incubator and placed over a hot plate heating Iodine solids. The smoke of the Iodine stained the plate to display the presence or absence of a halo around the bacteria 2.12 Lipid Hydrolysis This test was done by making a single line streak inoculation on a tributyrin agar plate and allowing incubation. After the incubation period, the plate was observed for the presence or absence of a halo around the bacteria.
Staphylococcus epidermidis is the organism that was identified based on the tests that I had conducted. The tests that I used to identify this organism were the coagulase test and the catalase test. My bacterium was beta hemolytic as well. First, a gram stain had to be done to determine whether the organism was a gram positive organism or a gram negative organism. This determined which set of tests that had to be done.
Each plate serves as a first step to identify the unknowns. The TSA (tryptic soy agar) can be used to do a gram stain, which differentiates gram-negatives from gram-positives, based on the structural make up of the cell wall (Carson, 2015). The blood agar plate is used to test for hemolytic activity, which is useful for distinguishing gram-positives. A MacConkey plate is selective by inhibiting the growth of gram-positives and differential due to the fermentation of lactose by certain gram-negative species. In the
Being able to identify unknown microbes from systematic testing is what makes the field of microbiology so important, especially in infectious disease control. Using the testing procedure laid out by the microbiology field we are able to identify unknown bacteria present in our everyday lives, and along the way learn a lot about their characteristics that separate them from other types of bacteria. Being able to do this is vital in order for us to understand why microbes are present in certain places, how they are able to grow and what restricts their growth, that way they can be combatted if necessary. These techniques for determining unknowns are also important for isolating and testing infectious disease microbes in order to prevent spreading. Another important aspect of being able to identify unknown microbes is the
Testing for the Presence of Macromolecules in McDonald’s Happy Meals Clayton Wagoner MST Biology White 4 duPont Manual High School Introduction Carbohydrates, lipids, proteins, and nucleic acids are organic molecules found in every living organism. These macromolecules are large carbon based structures. The macromolecules are assembled by joining several smaller units, called monomers, together through a chemical reaction called dehydration synthesis. The resulting polymer can be disassembled through the complementary process called hydrolysis.
Counting the bacteria means determining the number of bacteria in a specific sample. There are many ways that we can use to count the microorganisms, one of which is the plate count. The plate count technique is used to count only the living bacteria by counting the number of colonies. Due to the large number of bacteria, and to be able to count it, the bacteria should be diluted several times and spread on an agar plate. In this way, colonies can be counted.
Since unknown organism B was gram positive, I had decided my first biochemical test would be the Catalase test per lab manual. The result of the catalase test after adding H2O2 was immediate air bubbles. The second biochemical test performed on organism B was starch agar per lab manual. Once the reagent was added I did not
From the Unknown tube professor Cooper gave me, I scratched a little on the slant surface with the sterilized inoculating loop. Then I place it on a clean prepared slide which already had a slight drop of water. The two substances are mixed together in the middle of the slide and let dry completely. One extra step of “heat fix” is necessary to adhere everything to the surface of the slide. To start gram staining, I slightly pour crystal-violet all over the slide and let it sit for 30 seconds before wash it off with water.
This is a method in which when a stool sample is checked for bacteria under a microscope. It is the “gold standard” of cholera diagnosis. • • A rapid diagnostic test. This method is suitable for areas of limited laboratory resources. It provides early signs that a cholera outbreak is taking place at a location.
This can be tested by simply mixing the serum of suspected individual which contain the antibodies with the antigens of specific bacteria the accumulation of clumps confirms the presence of particular bacterial infection.[2] This test can be performed in various ways including slide agglutination reaction, tube agglutination reaction, indirect agglutination inhibition reactions etc. Another important practical application involves blood group test of
It also better to ensure that the materials like hemocytometer and pipettes are sterilized and clean so that there would be lesser or no artifacts would be seen under the microscope. The researcher was to use trypan blue exclusion method to test for cell viability, observe the non-viable and viable cells, and was able to have a cell count using the