Crystal Violet...
In a discussion, we were talking about the history of Gram staining.
Slowly talk shifted about the use of crystal violet MacConkey agar to inhibit Gram positive bacteria. But how a simple dye inhibit a group of bacteria and become a selective agent?
Here comes the answer,
"The mode of action put forward by Steam & Stearn (1928) that the action of crystal violet is due to the formation of an unionized complex of bacteria with dye, is supported. Gram-negative organisms, such as E. coli, have high isoelectric points and contain less acidic components than Gram-positive bacteria which usually have lower isoelectric points, so the former combine with crystal violet less readily and are more resistant to the dye. "
Very happy to discuss science with youngsters...
Source: http://onlinelibrary.wiley.com/doi/10.1111/j.2042-7158.1967.tb09550.x/abstract
Image Courtesy: http://www.evidentcrimescene.com
Slowly talk shifted about the use of crystal violet MacConkey agar to inhibit Gram positive bacteria. But how a simple dye inhibit a group of bacteria and become a selective agent?
Here comes the answer,
"The mode of action put forward by Steam & Stearn (1928) that the action of crystal violet is due to the formation of an unionized complex of bacteria with dye, is supported. Gram-negative organisms, such as E. coli, have high isoelectric points and contain less acidic components than Gram-positive bacteria which usually have lower isoelectric points, so the former combine with crystal violet less readily and are more resistant to the dye. "
Very happy to discuss science with youngsters...
Source: http://onlinelibrary.wiley.com/doi/10.1111/j.2042-7158.1967.tb09550.x/abstract
Image Courtesy: http://www.evidentcrimescene.com
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