Prokaryotes are still being researched and are a very diverse group. Hydrogen sulfide H2S was produced. When observing them under microscopes, we use various methods to make microbes apparent. To learn dyes used at different staining methods in differential staining Procedure: A Gram Staining In this procedure different types of bacteria are used throughout the laboratory. By using different stains, one can preferentially stain certain cell components, such as a nucleus or a cell wall, or the entire cell. Another theory such as presence of Magnesium ribonucleate in Gram positive bacteria and its absence in Gram negative bacteria has not received widespread acceptance. Please note that the quality of the smear too heavy or too light cell concentration will affect the Gram Stain results.
A Sulfur test was performed on Gram - bacteria. I much prefer 70% ethanol. Similarly, rapid decolorization may lead to under-decolorization of smear wherein Gram negative bacteria appear Gram positive. A smear of bacteria is prepared at the center of the slide in two methods as follows. Gram positive cell wall contain thick layer of with numerous teichoic acid cross linking which resists the decolorization. Staining techniques play an essential role in the studying of microorganisms; they help to reveal characteristics of microbes, such as their morphologies, sizes, arrangements, chemical components and many more. Research question: How does the different.
Therefore, microbes cannot be seen with our naked eyes thus different types of staining methods are used to increased visibility and contrast, accentuate specific morphological features, to detect extracellular and intracellular components of microbes and preserve them for future use. Bacteria, Enterobacteria, Enterobacteriaceae 1647 Words 7 Pages Gbengon,Sennie Microbiology Lab Case study 5 November 1,2012 1. Bacteria, Bacterial cell structure, Cell wall 1400 Words 6 Pages Gram Staining Introduction Prokaryotes are a large group of organisms with no membrane bound organelles. But if i may ask, which step in Gram staining tech can be omited without affecting the final result? The catalase test result was positive and Staphylococcas aureus was one the two unknown bacteria. Now, the stain- mordant complex is difficult to be removed by the decolourising agent and the cells retain the purple- blue colour of the primary stain.
When finished, lower the stage, click the low power lens into position and remove the slide. It is a prudent practice to always include a positive and negative control on the staining procedure to confirm the accuracy of the results Murray et al 1994 and to perform proficiency testing on the ability of the technicians to correctly interpret the stains Andserson, et al. The hypothesis of this experiment was that the bacterium is of the bacillus family due to the rod shape. Specimen B is fermented glucose and formed neutral end-products. Gram positive did not grow. Principle of Gram Staining When the bacteria is stained with primary stain Crystal Violet and fixed by the mordant, some of the bacteria are able to retain the primary stain and some are decolorized by alcohol.
This study was done by applying all of the methods that have been learned so far in the microbiology laboratory. In some cases, a rapid, presumptive identification of the organism or elimination of a particular organism is possible. While we provide a slide containing both Gram positive cocci and Gram negative bacilli in the smear for routine practical classes, you may get slides containing either of them alone or a mixture during your examination. Basic dyes consist of an anion that does not give off any color and a cation. Proteus vulgaris obtain energy and electrons from organic molecules. Do not use more than a 5 second water rinse at any stage of the procedure. The varying characteristics of bacteria play a crucial function in their identification Hogan, 2010.
Other alternatives include safranin and neutral red. We used a polysaccharide-containing material, in other words glycocalyx, lying outside of the bacterial cell to stain. Gram-positive bacteria did not grow. However, the bacteria that grew from these samples is not necessarily Acetobacter. Expected experimental result, Escherichia coli E. The following image shows what the tubes looked like for the Methyl Red portion of the test.
Blood agar test was also tested for Gram + bacteria. Heating the stain: Great care must be taken when heating the carbol fuchsin especially if staining is carried out over a tray or other container in which highly fiammable chemicals have collected from previous staining. The smear is flooded with the counter-stain, safranin, for 1 minute. Most stains can be used on fixed, or non-living cells, while only some can be used on living cells; some stains can be used on either living is or non-living What Cellularcells. Results The first test performed on the gram negative bacteria, was a Casein Test. All cells can be categorized either prokaryotic or eukaryotic and the primary difference between these two cell types is the presence of a membrane-bound nucleus. Dry smear, and cover the bacteria on the slid with crystal violet and wait for 1 min.
Depending on the results of each test we could narrow down the different bacteria to determine what our unknown is. This immediately ruled two of the gram positive bacteria Bacillus cerus and Bacillus subtilis. It is important to classify bacteria in order to identify them. The next test performed was a Nitrate Test which gave a positive result. This assignment is worth a total of 100 points — there are 20 questions worth 5 points each. The organism tested does not ferment mannitol. These dyes called negative stains, they stain environment like Indian ink staining.
In order to identify the Gram-positive bacteria, a sample from the original test tube was streaked on a Mannitol Salt Agar plate and placed in the incubator at 37 Degrees Celsius. Introduction In a lab today, I am to identify an unknown bacterium that is causing. Gram Staining is the most consistent when done on bacteria that less than 24 hours, while the older cultures may not retain the primary stain and give inaccurate results. This allows the Gram-negative cells to accept the counter stain safranin. It can also cleave a peptide from a synthetic substrate, yielding a chromophore p-nitroaniline which is yellow and can be measured photometrically at 385 nm Iwanaga 1987. A sample was taken from the isolated nutrient agar and a gram stain was done as directed by the lab manual 1. The Gram Staining Method is used as a tool for differentiation of Gram-positive and Gram-negative bacteria, as a first step to determine the identity of a particular bacterial sample.
Perhaps the most distinctive feature of our Type 2 bacteria is its reluctance to form distinct colonies, as can be seen in both the picture of the entire plate and the detail of only two distinct colonies that formed. Meanwhile, the slid with sample on was to fix the bacteria onto the slide. A Vibrio B Strepto C Spirillum D Staphylo E Cocci. One of the most important methods is staining. Specimen A fermented cytochrome oxidase. These organisms are only found in extreme environments such as volcanoes. This corresponds with Acetobacter, which also does not form endospores.