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Gram-positive bacteria have a thick mesh-like cell wall made of peptidoglycan (50–90% of cell envelope), and as a result are stained purple by crystal violet, whereas gram-negative bacteria have a thinner layer (10% of cell envelope), so do not retain the purple stain and are counter-stained pink by safranin. There are four basic steps of the ...
When some otherwise non-hemolytic bacteria, such as strains of the cholera-causing bacteria Vibrio cholerae, are plated on blood agar, no clearings are observed surrounding isolated colonies, but the blood surrounding larger areas of growth turns green. This process, called hemodigestion, is caused by the metabolic by-products of the bacteria ...
Giemsa stain is a classic blood film stain for peripheral blood smears and bone marrow specimens. Erythrocytes stain pink, platelets show a light pale pink, lymphocyte cytoplasm stains sky blue, monocyte cytoplasm stains pale blue, and leukocyte nuclear chromatin stains magenta.
Chemiluminescence (also chemoluminescence) is the emission of light (luminescence) as the result of a chemical reaction, i.e. a chemical reaction results in a flash or glow of light. A standard example of chemiluminescence in the laboratory setting is the luminol test. Here, blood is indicated by luminescence upon contact with iron in hemoglobin.
Fermentations: Light spots on some red blood cells are identified by LBA practitioners as fermentations caused by high sugar content in the blood. Fermentation is a chemical reaction of breaking down sugar into alcohol and carbon dioxide catalyzed by enzymes produced in yeast. The red blood cells are not yeasts and cannot ferment sugar. [13] [14]
Bioluminescence is a chemical reaction regulated by a gene or bacteria that enables living organisms to produce light naturally. Over 90 percent of marine organisms are bioluminescent -- algae ...
Blood is normally sterile. [1] The presence of bacteria in the blood is termed bacteremia, and the presence of fungi is called fungemia. [2] Minor damage to the skin [3] or mucous membranes, which can occur in situations like toothbrushing or defecation, [4] [5] can introduce bacteria into the bloodstream, but this bacteremia is normally transient and is rarely detected in cultures because the ...
Light microscopes are used for viewing stained samples at high magnification, typically using bright-field or epi-fluorescence illumination. Staining is not limited to only biological materials, since it can also be used to study the structure of other materials; for example, the lamellar structures of semi-crystalline polymers or the domain ...