Lactose

gram-negative bacteria, and differential between coliform and paracolon bacteria through its use of the pH indicator phenol red, bile salt detergents, and crystal violet to determine the affinity for particular gram-negative bacterium to ferment lactose (Carson, 2016). The following methods were repeated for each of the three agar plates available for experimentation during Week 1’s lab period to isolate pure, uncontaminated samples of individual…

Introduction: Lactase is an enzyme that helps to digest lactose, a sugar found in many dairy products (U.S National Library of Medicine 2013). This enzyme is made through instructions provided by the LCT gene. Lactase is primarily produced and found in the cells that line the walls of the small intestine. At the brush border, an area where microvilli absorb nutrients from food as it passes by, lactose breaks down lactose into simpler sugars like glucose through a hydrolysis reaction (Biology…

a pure bacterial culture. Materials and Methods 1. One test that was used to discover the identity of the given bacterial culture was the carbohydrate utilization tests. This specific set of tests involved two broths, namely phenol red lactose and phenol red sucrose, and a Durham tube placed upside down in the broth tubes. These broths can be broken down by fermentation processes, which produce an acid, gas or both. The broth tubes also contain a pH color indicator, which changes…

and is considered a byproduct of cheese production. Whey is a complete protein because it has 9 amino acids that are essential to us because we cannot naturally produce these amino acids. Additionally, whey comes with a low lactose content which allows people with milk lactose intolerances to still be able to enjoy whey protein. What Can Whey Protein Do for You? Whey naturally contains 9 amino acids meaning that it can supplement any normal diet. Body builders use whey protein to help bulk up,…

The goal of this experiment was to identify as well as learn about an unknown species of bacteria along with learning some techniques when it comes to process of elimination in a scientific study. To do this, many different tests were completed to help rule out species that were provided on a sheet of paper listing the possible candidates for the unknown microbe. The Bergey’s Manual of Determinative Bacteriology flow chart was also used to narrow down choices as tests were completed, along…

into Lac+ and Lac- organisms. The MacConkey agar is selective for Gram-negative bacteria, and differential between lactose fermenters (Lac+). The tests used for identifying these two bacterial species included: MacConkey agar plating, utilization of triple sugar iron, or TSI (and H2S), citrate, and urease testing. The TSI test was done to test for the fermentation of glucose, lactose, and sucrose, and signs of a black precipitate, H2S. The citrate test enabled us to see which organisms…

Title: What is The Effect of the Amount of Lemon Juice on the Mass of Curds? Purpose The purpose of the experiment was to investigate the effect of the amount of drops of lemon juice added to skim milk on the mass of the formed curds. Background Information Milk curd is defined as the byproduct of the effects of acid and enzymes on milk protein and fat (Milk Chemistry). Fresh cows milk has a pH of between 6.7 and 6.5. When milk is acidified, the fat and proteins begin to curdle, or…

MacConkey agar, which is media containing crystal violet and bile salts inhibits Gram positive bacteria (5). The media is also differential since the fermentation of lactose is detectable on MacConkey agar by pH indicators. Eosin Methylene Blue agar (EMB) contains chemicals that inhibit Gram positive growth and can identify lactose and sucrose fermentation through the previously described pH detection (3,5). Sometimes, media is developed to identify specific organisms. An example of this is…

The organism proved to be negative in citrate utilization, narrowing done the options to just three unknowns. The final tests needed to decide the identity of the unknown were the lactose and urease tests. A positive lactose resulted, along with a negative urease test. These two final tests, along with the tests before, led us to the conclusion of the unknown identifying as Escherichia coli. Very often throughout the testing and identification process…

Section 1: Tests used to identify unknown pathogen Mario F. Pedero a 30-year-old male visited his physician complaining of painful bumps and soars on his leg. The patient was diagnosed with HIV + 5 years ago. Due to his diagnosis, cutaneous disorders may manifest from the condition itself, or it can lead to opportunistic infections or infections that are more extensive than normal. The patient was sent to the emergency room were the physical examination revealed skin redness, papule lesions, and…