Bacteria, Bacterial cell structure, Bacteriology 659 Words 2 Pages Introduction Most common bacteria are either Gram-positive or Gram-negative based on cell wall structure. Always carefully read the entire label before using a chemical. Gram-positive bacteria appear purple and Gramnegative bacteria appear pink after staining. Through this experiment, gram staining skills develop. Inflammation occurs as a result of cytokine production, which can also produce host toxicity. It was critical to follow each step correctly while using sterile technique because from this test not only is the stain determined but also the shape of the cells.
Fig: Colour changes that occur at each step in the staining process. Procedure Three - Gram Staining 1. I noted this result and looked at the lab key to see what the results narrowed. Hypothesis — The experiment will allow for further insight into stained organisms, allowing extended contrast, differentiating shape and structure through utilization of microscope. They also have an additional outer membrane which contains lipids, which is separated from the cell wall by means of periplasmic space. This step was performed to kill the bacteria and attach it to the slide so it wouldn't wash off during the following steps.
There are also Autotroph bacteria that get their energy from photosynthesis or the oxidation of inorganic molecules. For simple staining basic dyes which are positively charged are used. Gram-positive bacteria are not decolorized by alcohol and will remain as purple. If the decolorizing agent is applied on the cell for too long time , the Gram-positive organisms to appear Gram-negative. Conversely, the outer membrane of Gram negative bacteria is degraded and the thinner peptidoglycan layer of Gram negative cells is unable to retain the crystal violet-iodine complex and the colour is lost. It is often the cause of postsurgical wound infections and one of the five most common causes of nosocomial infections Todar, 2012.
This explains the horrible effects of food poisoning that these two bacterium can have on a human. Do this several times to get maximum distribution. Bacterial vaginosis in pregnancy: distribution of bacterial species in different gram-stain categories of the vaginal flora. Results The first test performed on the gram negative bacteria, was a Casein Test. What is the purpose of staining samples? The purpose of this study was to identify an unknown bacterium by applying all methods that were previously conducted and learned in the microbiology laboratory class. As you do so, look for cells that are purple in color.
To avoid the spread and contamination of P. Which of the following stains is used to classify microorganisms based on their cell. They can be connected in chains, clusters or various other arrangements. The Gram-positive bacteria that are purple hold the stain due to it's layered cell membrane. Bacteria, Bacterial cell structure, Bacteriology 1775 Words 6 Pages Title: Staining Introduction: Microorganisms are small and colorless, invisible to unaided eyes.
S aureus can become pathogenic through tissue invasion and toxin pollution. The difference in charges between the cells and dyes causes an ionic attraction - keeping the dye attached to the cell. Reproducibility of interpretation of Gram-stained vaginal smears for the diagnosis of bacterial vaginosis. This is called gram-variable reaction. These features make the Gram stain method a more desirable screening procedure for bacterial vaginosis in a clinic population. As a result, the diffusion of the violet-iodine complex is blocked, and the bacteria remain stained.
Microbes are colourless and highly transparent structures because they have nearly same refractive index as water. This test was also incubated at 37 degrees Celsius for 48 hours and returned a good isolated colony. Some potential error in our experiment was not considering the possibility that the light switch had just been cleaned. Which of the following stains is used to classify microorganisms based on their cell wall content? Tables 1 and 2 lists the tests, purposes, reagents used and the results of each test. According to me, Grams staining process is a simple technique that assists in recognition of etiological agent and therefore can be called as one of the most significant staining practices in microbiology. At this stage, all cells will turn purple.
Mr Len artifacts results from poor methods of rinsing of slides. In all there were four different kinds of gram positive bacteria, two notably different types of gram negative bacteria, and only one gram insensitive bacteria. The culture was then inoculated onto a Mannitol Salt Agar plate. Use the fine adjustment, if available. Rebekah Worley February 21, 2012 Mitchell Section 4 Biol 311 Staining and Identifying Unknown Bacteria Introduction: The microbiology lab up to this point has been used to teach the students how to stain and identify bacteria. The gram negative bacteria in unknown 123 is a very aggressive bacteria that makes the growth of a gram positive bacteria difficult.
In this lab we focused on trying to identify if the bacteria found had a lot of peptidoglycan by gram staining. The slide is kept on a staining tray and flooded with the primary stain, crystal violet, for 1 minute. He saw this bacterium in pus inside an abscess in a knee joint. We accomplished this by transferring less culture material into each successive quadrant using gentle pressure. Procedure Two - Culturing Bacteria Using Aseptic Techniques 1.