gram staining

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gram staining

Postby scidely on September 14th, 2006, 12:38 pm 

a bacterthat has a cell wall composed of chemicals that readily absorb certain chemical lab dyes and become stained are called

a-gram positive
b-gram negative
c-Archaebacteria
d-none of above
scidely
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Postby tess on September 14th, 2006, 1:07 pm 

Gram-positive bacteria are classified as bacteria that retain a crystal violet dye during the gram stain process. Gram-positive bacteria will appear blue or violet under a microscope.

Gram-negative bacteria are those that do not retain crystal violet dye in the Gram staining protocol. Gram-positive bacteria will retain the dark blue dye after an alcohol wash, whereas Gram-negative do not.

work this our for yourself :D
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so

Postby graemhoek on September 14th, 2006, 2:24 pm 

Not quite, Tess. You're very close. It is not the crystal violet that stains the gram negative bacteria red but rather the counter stain. You can treat with just mordant iodine solution and crystal violet and get clear cells (gram negative) and purple cells (gram positive). Safranin confers a pink color to both bacteria but the purple is much brighter than the red so you just don't see it.
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Postby tess on September 14th, 2006, 2:30 pm 

:oops: I did biology so many years ago.
Sorry
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so

Postby graemhoek on September 14th, 2006, 2:31 pm 

Don't be sorry. We're all here to learn and I'm happy to teach where I can and learn everywhere else.
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Re: so

Postby Tranquil on September 17th, 2006, 2:11 pm 

graemhoek wrote:Not quite, Tess. You're very close. It is not the crystal violet that stains the gram negative bacteria red but rather the counter stain. You can treat with just mordant iodine solution and crystal violet and get clear cells (gram negative) and purple cells (gram positive). Safranin confers a pink color to both bacteria but the purple is much brighter than the red so you just don't see it.


Yes, but I think either you are not 100% right. Gram-negative bacteria does dye crystal violet, but doesnt hold this dye so much as G+ do. When decolorizing, then(in order to differentiate G+ and G-) Gram-negative decolorize. And thats the point. . . then we can counterstain them and thats why tey appear other color in light-microscope.
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so

Postby graemhoek on September 17th, 2006, 5:18 pm 

I think what fifik is referring to is the step post treatment with crystal violet where you apply alcohol to destain and subsequently differentiate the differing lipopolysaccharide layers of the gram negative and gram positive microbes.
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Re: so

Postby Tranquil on September 19th, 2006, 12:29 pm 

graemhoek wrote:I think what fifik is referring to is the step post treatment with crystal violet where you apply alcohol to destain and subsequently differentiate the differing lipopolysaccharide layers of the gram negative and gram positive microbes.


Yes you're right. The main thing, that we understand each other . . .
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Postby Kathryn on September 19th, 2006, 5:11 pm 

hehe, I remember gram staining in micro labs.
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Postby Tranquil on September 20th, 2006, 2:07 pm 

Kathryn wrote:hehe, I remember gram staining in micro labs.


:) I´m experiencing it right now :( I dont like microbiology a lot.
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Postby Kathryn on September 20th, 2006, 2:23 pm 

Yeah I didn't like micro either.
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so

Postby graemhoek on September 20th, 2006, 11:12 pm 

!? How can you do science without microbiology!? It's like the animal husbandry of molecular biology!
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Re: so

Postby Tranquil on September 21st, 2006, 4:52 pm 

graemhoek wrote:!? How can you do science without microbiology!? It's like the animal husbandry of molecular biology!


science has different faces . . . I´m doing laser stimulation of wound and burns. I dont need microbiology so far . . . And we have the bad teacher. So I really hate it ! But I havent said that I dont like immunology, that has much methods similar like ELISA, RIA, BLOTTING, immunoprecipitation and others . . . Including Flow cytometry, that I want to see once. We dont have it here in our city
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Postby Kathryn on September 23rd, 2006, 4:57 pm 

I find that there are alot of interesting topics in microbiology, but it wasn't really my thing. I guess everyone has different interests though
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Re: gram staining

Postby peterle on December 1st, 2017, 9:18 am 

Gram Staining is Procedure of Identifying Bacteria in Biology and Pathology Laboratories
The Gram Stain Kit (Modified Brown & Brenn) is intended for the demonstration and differentiation of Gram-positive and Gram-negative bacteria.

Gram Positive Bacteria: Blue
Gram Negative Bacteria: Red
Other Tissue: Slightly Yellow - Pink
Nuclei: Red
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