Ninhydrin tested for both amino acids and protein. The medium used in this test is the Simmons Citrate Agar, which is a type of utilization media. If you spill any reagent or acid, immediately notify your laboratory instructor. However, rabbinate had a greenish tint and our unknown matched in color more closely to ribose dark blue. After properly inoculating the urea broth with the unknown bacteria, the urea broth tube was incubated for 24 hours in a hot room of 37 degrees Celsius, they were checked after 24 hours and then incubated again for several more days to get proper results from the test. Why did you use these controls in this lab? They were positive and acidic. All proteins are polymers of amino acids, covalently bonded in long chains called peptide bonds.
Red brick precipitate is formed for positive results. So, the timing to heat the sample is set to 3. Because of this fact, we have deduced that vegetable oil is non-polar. If iodine added to a solution turns black-blue than starch is present positive test. This means that more than one test has to be performed in order to deduce which compound is present by process of elimination. Originally, a sample from the Unknown tube was supposed to be inoculated on a nutrient agar plate using the quadrant streak technique.
Glucose and fructose are monosaccharide. By using different glass pipettes, 5 ml of Fehling A and 5 ml of Fehling B are added into each test tubes. The gram positive bacteria did produce urease having a positive reaction, eliminating Staphylococcus aureus and leaving Staphylococcus epidermidis. This same goes for starch. Evaluation of Nutrients Test Control Unknown Benedict's Test Glucose- Turns the color red when glucose is present A - B + C - D - E + F - G + H + I - J + Iodine Test Cornstarch- Turns dark blueish black when starch is present A - B - C + D + E + F + G + H - I - J - Biuret Test Egg Albumin- Turns purple when protein is present A + B - C - D + E + F + G + H - I - J - Biuret Test Oil- turns dark brown and does not go away if oil is present A - B - C - D - E - F - G + H - I + J + Post Lab Analysis: 1. There are two possible results yielded from this test: a gelatinase-positive organism which breaks down the Gelatin medium into liquid, and a gelatinase-negative organism that does not liquefy the medium therefore meaning that it does not secrete gelatinases.
Fructose, lactose and glucose are reducing sugars which give brick red precipitate after the solutions are heated. The pathogenic cell produces slime, which is secreted from the teichoic acid in the cell wall, resulting in a biofilm formation. Lactobacillus is used for treating and preventing diarrhea, including infectious types such as rotaviral diarrhea in children and traveler's diarrhea. The Biuret test was used to detect the presence of peptide bonds within proteins, and they were found present in test tube 9 control for peptide bonds. Proteins are also made up of these base elements but it also contains nitrogen N. The gram positive bacterium did not isolate on the first nutrient agar plate so in order for the gram positive to grow it most be placed on a selective medium.
Oats did not react with the Benedicts test, but did react with the Iodine test; so it is a polysaccharide. You may have observed this reaction of oil and water in everyday experience. Starch, glycogen, dextran and cellulose are polysaccharides. They will repeat the process two more times. After the broth is incubated reagent A and B are added to determine if the reduction occurred; if the broth turns red a positive reaction occurs if not zinc is added.
These ions will then be precipitated as red copper I oxide which is not soluble in drinking water. Aldohexoses reacts so more slowly to form the same product. Distilled water gave negative test because it is not carbohydrate. Test tubes were removed and any color change was recorded for each in table 5. Gram positive organisms are able to retain the crystal violet stain because of the high amount of peptidoglycan in the cell wall. If test is positive it produces green color.
To confirm Staphylococcus epidermidis is the unknown gram positive bacteria a mannitol test was inoculated and incubated. If the tube of distilled water had shown a positive reaction, then I would have concluded that the sample was contaminated. That the purpose of heat it in longer time compare to sucrose. Gram negative bacteria cell walls have a thin peptidoglycan layer, in which an ample amount of lipids cross throughout the peptidoglycan and cell membrane. Glucose is a simple sugar with the molecular formula C6H12O6. Three drops of iodine were added to each tube and swirled.
Solutions can change color as a function of pH levels. All monosaccharides are reducing sugars; they all have a free reactive carbonyl group. The base elements of carbohydrates and lipids are carbon C , hydrogen H , and oxygen O. Incline the test tube and add carefully 2 ml of concentrated sulphuric acid along the side of the test tube so as to form 2 layers. Then, we turned on the hot plate. The iodine molecules slip inside of the amylase coil.
The study and test was done by applying all of the methods that have been learned so far in the microbiology laboratory class for the identification of an unknown bacterium which I was using unknown 25. A Simmons citrate test was performed it see if citrate was used a sole carbon source. The first technique that was performed was isolating the unknown broth on an nutrient agar plate, by streaking the unknown broth using the isolation streak method that was described in the lab manual. Materials and Methods The experimental material and methods used to carry out this experiment is out lined in the Biol. Within this test, all kind of carbohydrates gives a positive effect. The Iodine test is used to detect the presence of carbohydrates.