Exercise 6 : Quantitation Of Microbial Population

This table represents how many pill bugs were on each slice of filter paper, that had a different solution on each of them, over 30 second intervals lasting 5 minutes. This is what were recorded our data on for this part of the lab.

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

Purpose: The purpose of this lab is to help you become a little familiar with some of the tests that can be typically performed in a clinical or research lab facility. These tests may help in determining a particular pathogen’s growth needs.

There are many reasons for knowing the identity of microorganisms. The reasons range from knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics. This study was done by applying all of the methods that have been learned so far in the microbiology laboratory class for the identification of unknown bacteria. The identification process can be completed with a series of deferential stains and biochemical tests. Creating a dichotomous key helps to limit the amount of biochemical tests done on an unknown organism and by observation

In this experiment, an unknown bacterium was given to each individual student. The main purpose of this lab was to identify the given unknown bacteria going through a series of biochemical tests as one of the gram negative bacteria among six different Gram negative bacteria Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Salmonella typhimurium. At the very beginning, streaking method; T-streak technique was used to isolate the pure colonies. For the morphological identification of unknown bacteria, Gram Stain Method was done. Biochemical tests that were conducted for the experiment

1.2 ml of the bacterial cultures are taken to pellet the cells and remove supernatant while

An unknown bacterium 15 was awarded and labeled at the table ready to be identified. Using the skills and test that are taught and learned in microbiology were applied into learning what the unknown bacteria culture was. There were multiple procedures and test done in order to gain all the information needed to determine which bacteria was given. In order to find what the bacteria was the first step was finding the right environment and temperature that would allow the bacteria to thrive and grow. Determining this is one of the most important steps in being able to obtain conclusive results that would allow the results of the test to be accurate and correct. Without the correct temperature and environment the bacteria will give inconclusive results which will alter and skew the end results and may lead to the wrong conclusion. By using the methods that were obtained and learned through the microbiology class allowed the skills and knowledge to determine the bacteria and execute the tests in order to determine the culture.

Abstract: Microorganism need to live in ideal conditions so they can grow. This experiment was performed to determine if there was a greater number of microorganisms in Winthrop lake than Winthrop wetlands. We determined this hypothesis because the lake was bigger. We also made the hypothesis that the pH level of the lake was going to be higher than the wetlands. We tested out the hypothesis by going out to Winthrop lake and wetlands and collecting samples of water. Back in the lab, we examined the samples under a microscope and recorded all the organisms we could find on Excel. Also, we tested the pH levels of the

While completing the 5 tests I used medium that have a purpose selective and differential. Selective mediums “inhibit the growth of some organisms and encourage the growth of others” (1). Differential mediums differentiate between microorganisms using indicators such as color as the pH of the medium changes (1).

Flow Diagram Homework Assignment Name: Preetam Ganti Using the table below, explain the purpose of each of the steps of the Experimental Flow Diagram (Figure 1 from your lab manual – it is provided on the next page) for answering the two research questions guiding this laboratory investigation: 1. Is the bacterial contamination at these three farms due to the same plasmid or different plasmids? 2. What is the frequency of tetracycline resistant bacteria in the beef farm cultures?

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

of being able to analyze multiple samples in a short amount of time. The most efficient way of determining concentration is to prepare a set of standard solutions of known

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

Another purpose of this experiment is to stress the importance of knowing the identity of a microorganism. Knowing the species of microorganism present in a sample provides a

Six experiments were carried in this report concerning the effect that different environmental factors have on microbial growth. The results were recorded into tables where (+) symbolises growth and (–) symbolises no growth.