Western Governors University
A: In wet mount stain, color of the slide is same gray, colorless and glossy. Liquid or fluid appearance is visible. Bacteria and background don’t have a much of difference in color. Although, bacteria are defined and visible noted. Most of the time they are single round cells. In direct stain with crystal violet, again background is colorless and glossy. Bacteria is blue and some uneven grouping is noted. In this example the dye methylene blue stain is used. In indirect stain with Congo red stain, background is again colorless and glossy. Bacteria are orange to red and fine defined. At smaller magnified example they are grouping in uneven clusters, but in highest magnifier we can see single bacteria dark cell. B: On each examples bacterial morphologies are visible and easy identified. In the wet mount example with yeast, cocci is noted, while is hard to determine in cheek smears. Check smear and yeast smear contain cocci with direct staining. At direct staining plaque smear contain cocci and bacillus. Yeast with indirect staining contains cocci as well. On same picture bacteria are singled while on some pictures bacteria are in group and uneven clusters. Different type of stain plays role to differentiate the shape of bacteria. C: When we are talking about difference between direct and indirect stains, main importance is acidity of the dye. Dye that we are using in direct staining is basic. The colored part of this dye is positive charge, but when in contact with negative cytoplasm of bacteria, at that point bacteria change color and become stained with purple hue. For direct staining we are using crystal violet or methylene blue stain. For indirect staining we are using dyes that are acidic. Usually we are using Congo red, nigrosine or India ink. The acidic dye contains negatively charged color portion. When applied and...
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