Explain Why Is It Important To Have A Mixed Culture

One of these reasons is in regards to pathogens. If a bacterium is pathogenic, it is important to know the identity of the bacteria so that its characteristics can be examined and used in the treatment of the infected host. For example, if the identification of an unknown pathogen leads to the knowledge that the pathogen contains a beta-lactam ring in its cell wall, a drug targeting this cellular component can be used in the treatment of this pathogen. If this information was unknown and the pathogen did not contain a beta-lactam, the drug would not help the infected host. Another reason it is beneficial to identify unknown bacteria is for clinical uses. Many pharmaceutical drugs are based upon or isolated from products made by bacteria. Penicillin is an obvious example of a beneficial drug that was isolated from a mold. By identifying new bacteria and discovering the unique properties of a new or under researched species, beneficial medical products may be able to be derived or produced as a result. A third important reason to identify bacterial unknowns can tie into the safety and conservation of the environment. Because of the varying properties and abilities of bacteria, it is beneficial to identify bacteria that may be able to help clean up human impact. For example, Alcanivorax borkumensis, is a bacterium that has been discovered to aid in the cleanup of spilled petroleum. Other bacteria have been discovered to aid in eating pollution and other toxins in water. The identification of important bacteria such as these can lead to increased efforts in environmental conservation that use a more organic clean up approach.

This experiment was centered on metabolic and biochemical testing procedures. The rationale of performing these tests was to distinguish six different microbes from one another and to compare how their metabolic and biochemical processes differ from species to species to determine the unknown sample.

3. Microbiologists employee a number of approached to acquiring a pure culture from a from sample containing a number of different types of bacteria. Briefly describe three different procedures commonly used to secure pure cultures from a mixed culture. The use of simple labeled diagrams may be quite helpful.

Read in your lab manual about the following agar mediums: Blood Agar (pg 168), EMB Agar (pg 170), Mannitol Salt Agar (MSA)(pg 172) ), MacConkey Agar (pg 174), and PEA Agar (pg 176) to answer the following:

Being able to figure out an unknown culture or bacteria is very important and a great knowledge to have. It helps people every day from finding cures to bacterial infections, discovering new kinds or simply just knowing the limits of what they are capable of. It allows scientist to know how to kill them treat then and ect. along with determining if they are harmful or benefit humans, and plants Along with being able to identify different species of

For this particular assignment, I was given a slant with an unknown bacteria by my lab instructor. There were several procedures performed to identify the unknown bacteria. The first procedure was streaking tryptic soy agar plate (TSY). The purpose of streaking is to identify the bacteria in a sample presenting a pure culture of colony morphologies. After several hours of incubating the streaked plate, visual isolated colonies were present. The steps to streaking are as follows; Flaming an inoculation loop with a Bunsen burner until red hot, then allow to cool before taking the unknown bacterial sample. Streaking four quadrants onto the TSY medium plate by dragging the loop gently through first quadrant then sterilizing the loop by flaming it again. This procedure was continued into the third and fourth quadrant. The second procedure performed was the bacteria smear. The motive of the smear is to have the bacteria ready for a stain after it has been heat fixed on a slide. These steps conclude by first labeling the slide with the my initials, flaming the inoculated loop, then allowing the loop to cool before spreading the unknown bacteria on slide after instilling a drop of distilled water. This process took about 10 minutes for the wet surface to dry before heat fixing. Heat fixing is when a bacteria smear is smeared on a slide and dried at room temperature before passing a slide through a hot flame of a Bunsen burner. Soon after the slide had been heat fixed and

You can grow microorganisms in liquid media or on solid media. Most bacteria can be grown in labs as long as the media contain a source of the major nutrients; carbon, nitrogen, sulphur, and phosphorous. They may also need to have other nutrients. These nutrients are made into a broth and the pH and salinity can be adjusted. The nutrient broth is placed in test tubes, which are plugged with cotton wool, capped with foil and then sterilised in an autoclave, at 121c for 20minutes. These tubes are then cooled before they are inoculated. To prepare the streak plates we dipped an inoculating loop into ethanol then placed it in the flame until the loop glowed red. Still holding the inoculating loop by its handle we removed the lid from

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).

In the 10-3 pasteurized sample, the plate exhibited 71,000 cells/mL. The results of the additional dilution samples contained too few colony forming units to count. However, in the 10-7 dilution, although the plate demonstrated 12 colonies, there should have been no colony forming units on this plate. The reasons for this could have been that this sample was contaminated from “double-dipping” the sample before dispensing it onto the plate or when using the pipette, it mistakenly was inserted in a higher concentration sample and then immediately to a lower concentration sample before it was dispensed onto the plate.

Most selective growth media contain a protein source and a fermentable sugar. Selective medium types include EMB agar, Mannitol Salt agar, MacConkey agar, and Phenylethyl Alcohol (PEA) agar. Differential media distinguish microorganisms from one another based on their biological characteristics. Examples include blood agar, Eosin Methylene Blue agar, Mannitol Salt agar, and MacConkey agar. Some medias contain both selective and differential properties.

In order to obtain well-isolated discrete colonies, the quadrant streak and spread technique was used. This allowed dilution of the original microbial material over the entire surface of the plate. As the original sample was diluted by streaking and spreading it, over successive quadrants the number of organism decreases. Usually by the third or fourth quadrant only a few organism were transferred on the by the inoculating loop and theses produce a few isolated

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

The purpose of this experiment is to obtain isolation of individual species of particles from the mixed culture. This is completed through the isolation technique of streak plate. The objective of this experiment is to replicate the technique of streak plate but on a much larger scale. Because it is on a larger scale the particles are able to be visually observed as they are isolated using the streaking technique as the experiment is conducted. The benefits of the streaking technique is when a cultures has multiple species they are able to be more easily identified once they have been isolated. This experiment is much like the experiments completed on an agar plate but on one a much larger scale and where techniques

-Sterility: Each sample will placed in a sealed bag, preventing the introduction of extraneous bacteria.

THEORY: Nutrient agar media is used to facilitate the growth of the wide range of non-fastidious bacteria.