Tuesday, October 1, 2019

Gram Staining and Distilled Water Essay

The purpose of this experiment was to learn how to properly perform a gram stain and to also understand how gram staining can help identify either gram-positive or gram-negative organisms in the laboratory. The materials needed for this experiment included: two microorganisms (Staphylococcus aureus and Pseudomonas fluorescens) in a slant agar, an inoculating loop, a microscope slide, distilled water, a Bunsen burner, four dyes (crystal violet, Gram’s iodine, ethyl alcohol, and safranin), bibulous paper, and a dye tray. The method for this experiment was as follows: 1) Cleaned the microscope slide with both soap and water and then dried 2) Flamed the inoculating loop with the Bunsen burner and then applied two small drops of water to each side (horizontally) of the slide 3) Flamed the inoculating loop again, allowed it to cool, and obtained a small sample of the first organism 4) Mixed the organisms on the inoculating loop with one of the drops of the water on the slide and spread to a nickel-sized drop 5) Repeated steps 3 and 4 for the other organism using the second water drop on the slide 6) Allowed the samples to dry and then heat fixed both samples. Applied the crystal violet dye, let it soak for 20 seconds, and then washed the dye away with distilled water off into the dye tray 8) Applied the Gram’s iodine and let it soak for a minute 9) Washed it off with alcohol for 20 seconds (or until the dye stopped running), and then immediately washed with the distilled water 10) Applied the counter-stain, safranin, and let it soak for a minute. 11) Washed with distilled water after and gently blotted it dry with bibulous paper 12) Observed both microorganisms on slide under the microscope Two different results were observed under the microscope. The first one was purple colored cocci, and the picture of the slide is on the following page. The second one revealed pink-colored rods, and the image is on the page following the first microorganisms. The results of the experiment came out as expected. There didn’t seem to be any flaws in the experiment, since the colors were distinctly different. The purple cocci were identified as the Staphylococcus aureus. Because the violet dye penetrated the membrane and stained it, it was recognized as a gram-positive organism. The pink rods were Pseudomonas florescens. It was discovered to be a gram-negative organism because the organism didn’t stain from the crystal violet. Since everything was easily identifiable, the experiment seemed to have gone as planned.

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