Staining Techniques Lab Report

a)What type of stain would you use to determine whether there had been any changes in total cell number following administration of the neurotoxin?

First a thin smear of bacteria, placed on a clean slide, covered with crystal violet stain for 1 minute. Next, completion of a wash and then an iodine solution is added to the smear to enhance staining for 1 minute. Being rinsed again in water and then 95% ethanol for one minute. Washing the violet stain off will differentiate between the two types of bacteria. If the bacteria retains the violet color, it means they are gram positive, while the others without strain are gram negative. The cell wall of the gram positive bacteria has a thick outer layer made up of peptidoglycan and the cell plasma membrane causing the stain to stick. The gram negative bacteria has an outer layer made up of lipopolysaccharides and proteins and then a thin layer of peptidoglycan and the plasma membrane. The lipids from the outer membrane dissolve with the ethanol wash, causing them to lose the violet stain. After the ethanol wash, the smear is washed in water and stained with safranin for one minute allowing for the gram negative bacteria visualization. Before the

This stain is helpful and widely employed for any kind of overview staining, modified toluidine blue includes glacial-sulpharic acid, this reagent was used for treating the smears prior to staining, sulphation stage help to clear background material from the preparation by digesting away most of the background material in which almost all background material was removed in both lavages and sputum, and not affect either fungal elements or P. jirovecii enabling the cysts to be seen more clearly, it is specific for cysts and more rapid than silver stain, the disadvantage of modified toluidine blue is the using of noxious chemicals, It may be harmful when inhaled (152).

Finally, the slide is washed again and stained with a counterstain, such as safranin. The counterstain will dye the gram negative cell and will not effect the gram positive cell.

Repeat steps 4-5 with a CLEAN SWAB to serve as reference to distinguish the colour change

In this lab, we used the procedure from Differential and Special Stains. This experiment was similar to the Simple Stain experiment but only a few changes were made to it. After we had gone with the heat-fixing the slide, we covered the slide with crystal violet, and we left it on fore 30 seconds. We rinsed the slide gently with a wash bottle water and we also covered the slide the slide with iodine for 12-60 seconds. We rinsed the slide again with a wash bottle water and then we held

The purpose of the gram stain test is to see if an organism is gram negative or gram positive based on it’s color and shape. Using an inoculating loop and inserting it into the incinerator for 10 seconds, it was sterilized. A small drop of water was then applied onto a clean glass slide by using the now sterile inoculating loop. The loop was used to spread the organism back and forth on the slide until a good portion of the glass is covered. The organism and water were left to dry completely before heat fixing the glass slide. After heat fixing, over a sink crystal violet was applied to the glass slide for one minute. It was then rinsed with water and iodine was applied for one minute. The slide was then rinsed with water and 95% ethanol was

The Gram’s staining procedure is still used today and is the method that forms the basis for identifying bacteria. In order to perform this procedure, you will need a Bunsen Burner or a Tirrill burner, alcohol- cleaned microscope slide, and water. You will also need The following reagents: Crystal violet, Gram’s iodine solution, 95% alcohol, and safranin. These stain reagents are important because they are used to determine the Gram reaction for microorganisms’ identification. Crystal violet will stain the bacterial cell, and Iodine will bind the stain. The alcohol differentiates bacteria retaining or not the crystal violet within the cell wall, and the safranin will be used as a counterstain to stain the bacteria. You are now ready to start you process.

The reaction of the Gram-stain in a bacteria is determined by the biochemical composition within that bacteria. Gram-positive cell walls are composed of tightly linked peptidoglycans which traps the iodine complex, thus retaining the violet color after decolorization is complete. Gram positive,on the other hand, have a

Indicated by its name, this method of hystogical staining involves two dyes. The first of which is Hematoxylin. As a basic dye, hematoxylin works as an acidophilic substance. Because of this, it stains nucleic acids blue and purple. Thus, with this stain the nuclei of cells are stained blue. The second dye, eosin, is basophilic. Any basic or negatively charged structures, like proteins with cationic amino acid group, are stained pink. Of the two, eosin tends to be the overpowering stain, coloring cytoplasmic content, muscle and connective tissues, erythrocytes, and various other cellular content.

The Gram stain uses crystal violet as a primary stain, ethanol-acetone as a negative stain, and safranin as a counterstain. A small amount of the culture was heat-fixed to a glass microscope slide. The culture was flooded with methylene blue, and allowed to sit for one

The Gram stain is a chemical preparation which allows bacteria to be classified into Gram positive and Gram negative by their ability to retain the stain. Bacteria which keep the purple stain are Gram positive and those that loose the stain or turn a pink colour are Gram negative. This procedure is based on the differences in the cell walls structure. The bacterial cell walls will all contain peptidoglycan but the gram positive bacteria the peptidoglycan layer will be thicker. Gram negative, as well as having a thinner peptidoglycan layer, will also have lipopolysaccharides covering the peptidoglycan layer causing less of the stain to be retained.

When viewing live specimens with the microscope it can be very difficult to see. What makes slides hard to examine is the contrast between a cell and its background, which are both primarily water. In order to provide information and characteristics about the chemistry of a specimen a method called, staining is used to increase its differences. Stains/dyes are a salt that colors the ion it penetrates. There are two types of colors retrieved when staining; in a basic stain the color appears in the positively charged ion, while in an acidic stain the color is in the negatively charged ion. Examples of basic dyes include: methylene blue, crystal violet, and safranin.

The purpose of this process is to be able to determine the morphology and arrangement of bacterial cells. No heat fixation or other chemicals are done to the slide. After performing my simple stain technique using crystal violet, the morphology of my unknown was bacillus and the arrangement was singly.

3. Describe the process of how bacteria can be identified by their metabolic products using indicator media.