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gram stain Explained

gram stain at English => English (The Britannica Concise) Of Explained:

Universally used staining technique for the initial identification of bacteria, devised in 1884 by the Danish physician Hans Christian Gram (1853-1938). The stain reveals basic differences in the biochemical and structural properties of a living cell. A slide containing a smear of bacteria is treated with a purple dye; the slide is then dipped in an iodine solution, followed by an organic solvent (such as alcohol) that can dissolve the dye. Gram-positive bacteria remain purple because they have a thick cell wall that the solvent cannot easily penetrate; gram-negative bacteria lose their color because they have thin cell walls that allow the solvent to penetrate and remove the dye.

Gram stain at English => English (WordNet) Of Explained:

Gram stain
n : a staining technique used to classify bacteria; bacteria are
stained with gentian violet and then treated with Gram's
solution; after being decolorized with alcohol and
treated with safranine and washed in water, those that
retain the gentian violet are gram-positive and those
that do not retain it are gram-negative [syn: {Gram's
method}, {Gram method}, {Gram's procedure}, {Gram's stain}]