E. Coli Experiment

Depending on what a bacteria can and cannot do, will help to correctly identify it. It is always important to start out with a purity check. To achieve that, you can inoculate an agar plate and incubate for 48 hours. Make sure you only see one type of colonies on the plate. Knowing the optimal temperature for the bacteria will also let a scientist know where to place the different types of medias he/she inoculates with the unknown bacteria. Knowing if you are working with a gram positive or gram negative bacterium, a scientist will need to perform a gram stain. This will also help to see the shape and arrangement of the bacteria. The size can be determined by doing a simple stain. The size of most bacteria ranges from .5- 10um. This specific bacteria that I was working with, was smaller than 2um. Most bacteria can grow with the presence of oxygen. A simple test like the gas pack can be performed to figure out if growth is possible without oxygen is doable. My unknown bacteria needs oxygen to grow. Throughout my study, the unknown bacteria was tested to see if it can grow in acidic conditions, however no growth occurred. Before inoculation, the substrate was a clear yellow color and in liquid state. After receiving the negative result, I kept the broth in the 37C incubator for 7 more days to confirm the negative result. Using premade slants with different types of sugars such as Mannitol, Sorbitol, Lactose, Trehalose, Maltose and Sucrose, to determine if the bacteria can metabolize glucose and if the bacteria is oxidative or fermentative. It was determined that my bacteria is strictly oxidative (needs oxygen to grow) and cannot metabolize glucose. Another test was done to confirm if the bacteria was able to utilize different carbohydrates in the presence of oxygen. I used Cellobiose, Arabinose, Adonitol, Fructose and Malonate wee tabs. Out of the 5 different types of carbohydrates, only 3 different

The purpose of this lab was to identify two unknown bacteria from a mixed culture. The reason for identification of unknown bacteria was to help students recognize different bacteria through different biochemical tests and characteristics. This is important in the medical field because identification of unknown bacteria can help treat a patient by knowing the contributing source of a disease. Also knowledge of different bacteria helped others make antibiotics used today. This lab was completed by using the methods learned thus far in identification of bacteria.

The first result of importance was the result of the Gram stain. The observations of the unknown bacteria from the slant culture after Gram staining showed that the unknown bacteria were Gram negative bacilli (Image 1). After determining the unknown bacteria was Gram negative, an oxidase test was conducted on a sample from the slant culture. The cotton swap with the sample of bacteria did not change color when the oxidase reagent was applied, thus providing a negative result. With a negative oxidase test, further tests were conducted to determine various characteristics of the unknown bacteria. A MR-VP broth was inoculated with a sample from a slant culture of unknown bacteria. After incubation, the methyl red reagent was added to the broth, and the broth turned red, providing a positive result (Image 2). An EMB agar streak plate was inoculated with a sample from a slant culture of the unknown bacteria, and after incubation, growth was found on the plate, providing a positive result (Image 3). A Citrate agar slant was inoculated, and after incubation, growth was found on the media, providing a positive result (Image 4). A Urea agar slant was inoculated, and after incubation, the agar had changed from a peach color to a bright pink color, providing a positive result (Image 5). Using the flowchart (Figure 1) developed from the Table of Expected Results, the lab partners started at the oxidase test. Given the negative result of the oxidase test, the flowchart is

The purpose of this lab was to identify two unknown bacteria cultures using various differential tests. The identification of these unknown cultures was accomplished by separating and differentiating possible

The purpose of this lab was to identify two unknown bacteria cultures using various differential tests. The identification of these unknown cultures was accomplished by separating and differentiating possible bacteria based on specific biochemical characteristics. Whether the tests performed identified specific enzymatic reactions or metabolic pathways, each was used in a way to help recognize those specifics and identify the unknown cultures. The differential tests used to identify the unknown cultures were oxidase, catalase, lactose and sucrose fermentation, Kugler/iron agar, nitrate reduction, gelatin hydrolysis, starch hydrolysis, manitol salt, MR-VP, citrate, bile esculin,

2. List what it is caused by (specific scientific and common names of the organism: Escherichia coli

CDC says that 63 people were infected with the outbreak strains of E.Coli 0121 and that 026 have been reported from 24 states. The sickness started from December 21, 2015 to September 5, 2016 and 17 sick people were hospitalized. CDC found out that some people who got sick had to of eaten or dealt with raw dough. FDA’s investigation determined that the raw dough restaurants were using General Mills flour that had to of been produced in November of 2015. General Mills flour manufactured that it was likely to be the source of the outbreak. General Mills contacted all of the costumers who have gotten flour from there and told them about the recall. FDA and General Mills are working together to make sure that the costumers have all been notified.

This experiment is about bacterial growth. We will demonstrate a bacterial growth curve using a closed system. Bacterial growth usually takes up to 12-24 hours to get an accurate result so we will be monitoring this growth between two classes. We also used different methods to determine bacterial growth as well as a few different calculations. One way of receiving data is by using a spectrophotometer where we will record the absorption at a given time to create the bacterial growth curve. We also used the plate count method after performing a serial dilution to calculate the actual cell density at different times given. By using this method we can count the population number of the same given and see the maximum cell density

The impaired portion of Brock Run (TMDL ID: VAN-F15R BRK01A06), located in Spotsylvania County, was first identified as impaired for E. coli bacteria on VADEQ's 2008 303(d) Total Maximum Daily Load Priority List because of exceedances of the state's water quality criterion for E. coli bacteria. The 2.56 miles long impaired segment begins at the confluence with Aunt Sarah Spring Creek, which is approximately 0.95 miles downstream of Ashbys Pond, and flows to the confluence with Ni River. According to the 2014 Water Quality Integrated Assessment period (February 11, 2004 – December 31, 2012), 6 out of 19 samples (31.6%) surpassed the maximum water quality assessment criterion (235 cfu/100ml) for E. coli bacteria at Station 8BRK000.06,

Abstract:Conjugation is a natural occurring process that involves the transfer of DNA from one cell into another through a physical connection between the cells. In the following experiment, two strains of Escherichia coli bacterial cells (donor F'lac+strs and recipient F-lac-strr) underwent conjugation to produce a transconjugant strain (F'lac+strr). MAC plates and streptomycin were utilized to determine if conjugation had occurred. When plated, the donor colonies appeared red and the recipient colonies appeared white. The transconjugant plates showed red and white colonies. Using alkaline lysis miniprep, a DNA plasmid was isolated from the donor and transconjugant strains and FIGE electrophoresis was used to determine the size of the

After incubating of the two replicate strains of E. coli each in the 0%, 0.1%, 0.25% and 0.5% garlic extract dilutions, the optical densities of E. coli were taken at an absorbance reading of 600 nm in a spectrophotometer over a growth timespan of 25 hours. The exponential growth curves as seen in Figure 2A were measured from the timepoint of the hour 2 to hour 6, the growth phase, which was where majority of the growth grew in an upward slope, and then the growth curves had slowed into the stationary phase around the seventh to eighth hour where the growth curves were becoming more constant all the way to the 25th hour timepoint as seen in Figure 1A.

In this lab experiment, students had to create a growth curve for E. coli. The E. coli growth curve would illustrate the progression of the population of E. coli a set time period. In this case, the growth curve depicted the population of E. coli over a 12-hour period. The growth curve for E. coli was created from the absorbance levels, the optical density(OD), recorded from the spectrophotometer.

2. Introduction: Each student was given unknown bacteria and was instructed to perform a variety of experimental tests that would help to identify their bacteria. During the process of identification, the unknown bacteria was added to many different testing medias using aseptic technique. They are as follows: lactose fermentation on eosin methylene blue (EMB), TSI (Triple Sugar Iron agar), Phenol red sucrose, the SIM test, H2S by SIM, IMViC (indole, motility, voges-proskauer, and citrate), Urease (urea broth), PDase (Phenylalanine Deaminase), Lysine Decarboxylase, and Ornithine Decarboxylase. Colonial morphology on EMB was used to

Introduction: Through the conduction of numerous experiments, the identity of two bacterial isolates was determined. The tested specimen was an unknown sample of a mixed culture of two different species of bacteria. The first step that was taken was obtaining a pure culture of each species of bacteria by isolating one species from the other. Once isolation was complete, the isolated cultures were tested using procedures that had been performed during previous lab sessions. A gram stain was performed on the two isolates. The isolate which had tested gram negative was then tested for the presence of cytochrome C and lactose fermentation. For the gram positive isolate, cell shape was determined and a catalase test was performed.

This experiment was performed to test the hypothesis if LB nutrient broth, +pGLO and -pGLO Ampicillin, and Arabinose was placed in the E. coli plates, then there will be a significant growth in the newly transformed bacteria and it will possess the ability to glow under UV light. The measurements were recorded from the bent glass tube in each glass test tube. The transformation protocol tested for the newly possessed traits in E.coli bacteria. Throughout the experiment there were many probable reasons for failure. If the pipettes and sterile loop were not thrown out in between each use, a cross contamination could cause a miscalculation in the experiment causing the data results to fail. The hypothesis that was tested was validated due to the positive results with each experiment stating that newly transformed organisms due in fact pass on traits.