crystal violet is the primary stain in the gram stain.
what is the primary stain in the gram stain?
crystal violet
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 gram stain:









































bullet::::- applying a primary stain (crystal violet) to a heat-fixed smear of a bacterial culture. heat fixation kills some bacteria but is mostly used to affix the bacteria to the slide so that they don't rinse out during the staining procedure.
gram stain
some bacteria, after staining with the gram stain, yield a gram-variable pattern: a mix of pink and purple cells are seen. in cultures of bacillus, butyrivibrio, and clostridium, a decrease in peptidoglycan thickness during growth coincides with an increase in the number of cells that stain gram-negative. in addition, in all bacteria stained using the gram stain, the age of the culture may influence the results of the stain.









































gram-indeterminate bacteria do not respond predictably to gram staining and, therefore, cannot be determined as either gram-positive or gram-negative. examples include many species of "mycobacterium", including "m. tuberculosis" and "m. leprae".
gram stain