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Unlike negative staining, positive staining uses basic dyes to color the specimen against a bright background. While chromophore is used for both negative and positive staining alike, the type of chromophore used in this technique is a positively charged ion instead of a negative one.
Basic dyes are also used in the coloration of paper. Direct or substantive dyeing is normally carried out in a neutral or slightly alkaline dye bath, at or near boiling point, with the addition of either sodium chloride (NaCl) or sodium sulfate (Na 2 SO 4) or sodium carbonate (Na 2 CO 3). Direct dyes are used on cotton, paper, leather, wool ...
It describes the appearance of cells, tissues and cellular structures as seen through the microscope after a histological section has been stained with a basic dye. The most common such dye is haematoxylin. The name basophilic refers to the characteristic of these structures to be stained very well by basic dyes. This can be explained by their ...
Counterstain, which is usually positively charged safranin or basic fuchsine, is applied last to give decolorized gram-negative bacteria a pink or red color. [3] [20] Both gram-positive bacteria and gram-negative bacteria pick up the counterstain. The counterstain, however, is unseen on gram-positive bacteria because of the darker crystal ...
The mechanism of action of the Ziehl-Neelsen stain is not completely understood, but it is thought to involve a chemical reaction between the acidic dyes and the cell walls of the bacteria. The acidity of the dyes causes them to bind more strongly to the cell walls of the bacteria than to other cells or tissues. This results in the selective ...
Trypan Blue, a living-cell exclusion dye; Triphenyl tetrazolium chloride; Erythrosine, which is Red No. 3 in food coloring, can be used as an exclusion dye. 7-Aminoactinomycin D used e.g. in flowcytometric studies of hematopoietic stem cell viability. Other Vital Stains : Janus Green B is a basic dye and vital stain used in histology.
The H&E staining procedure is the principal stain in histology [3] [7] [2] [5] in part because it can be done quickly, [7] is not expensive, and stains tissues in such a way that a considerable amount of microscopic anatomy [9] [10] is revealed, [7] [5] [4] and can be used to diagnose a wide range of histopathologic conditions. [8]
Adjective dyes are those dyes that require use of a mordant to bind the color to the fiber. [2] alkanet Alkanet or dyer's bugloss (Alkanna tinctoria) is a traditional plant source of red dye. [3] alum Alum (aluminum sulfate) is a naturally occurring basic mordant widely used in the ancient world. [4] añil