A set of two stains that are used to stain (crystal violet and iodine) and counterstain
(fuchsin) bacteria.
Gram-negative bacteria are completely decolorized after treating the stained bacteria
with ethanol or acetone and can be visualized by the counterstain. They have a complex
cell wall in which the
peptidoglycan layer is covered by
lipopolysaccharides in an outer
membrane structure.
Gram-positive bacteria resist decolorization by ethanol or acetone, they retain the initial
Gram stain. They have a cell wall consisting predominantly of
peptidoglycan not overlayed by an outer
membrane.
Source:
PAC, 1992, 64, 143
(Glossary for chemists of terms used in biotechnology (IUPAC Recommendations 1992))
on page 155
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.
