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Why can tooth and gum bacterium be seen with negative staining?
Not all oral bacteria are gram negative, but those that are there can be seen with Gram stain.
Why can treponema denticola be seen with negative staining?
Because it is a Gram-negative bacterium and can be stained with Gram-negative stain.
Can Gram-positive organism appear as Gram-negative?
Staphylococcus are Gram positive because, in Gram's test, the decolorizing agent (ETOH) cannot penetrate the thick cell walls, and the stain remains behind: hence Gram positive. I am not aware of a gram negative staph species and, considering the degree of mutation that would be needed to form such a strain, I do not believe that it's possible. I should add that a not-so-brief scan of the net showed me no Gram negative staph mentioned anywhere. So -- for now -- no. That said, let's see what the future holds.
Are human cells gram positive?
Human cells are Gram-negative because they do not contain certain structures. More simply, if they don't have a cell wall they cannot be Gram-positive.
Biochemical tests to confirm micrococcus luteus?
I had a bacterial unknown of M. luteus in my microbiology lab. M. luteus is a Gram positive cocci (as seen by a gram stain). A good definitive test for Gram + cocci is the catalase test. M. luteus is catalase positive. Then a nitrate test can be performed to determine that M. luteus is nitrate negative. Those alone should be enough to confirm M. luteus.
Why can tooth and gum bacterium be seen with negative staining?
Not all oral bacteria are gram negative, but those that are there can be seen with Gram stain.
Why can treponema denticola be seen with negative staining?
Because it is a Gram-negative bacterium and can be stained with Gram-negative stain.
What is the current theory about the mechanism of the gram stain?
The gram stain is a basic differential stain used to determine if a bacterial cell is gram positive or negative. Gram positive cells have a thick peptidoglycan layer that will trap the crystal violet iodine crystalls and apear purple. Gram negative cells only have a thin peptidoglycan layer that allows the crystals to diffuse out of the cell and will only be seen with the application of a counterstain, such as safranin which turns the cells pink.
Can Gram-positive organism appear as Gram-negative?
Staphylococcus are Gram positive because, in Gram's test, the decolorizing agent (ETOH) cannot penetrate the thick cell walls, and the stain remains behind: hence Gram positive. I am not aware of a gram negative staph species and, considering the degree of mutation that would be needed to form such a strain, I do not believe that it's possible. I should add that a not-so-brief scan of the net showed me no Gram negative staph mentioned anywhere. So -- for now -- no. That said, let's see what the future holds.
WHAT ARE the different reagents in gram stain method and its uses?
Mordant is the reagent used in the gram stain method. By using this type of reagent bacteria are more easily seen. It is important to a doctor to know what kind of bacteria is present so that he knows what to prescribe to a patient to get rid of the bacteria.
What is a decolorizer do in gram staining?
It removes the crystal violet (primary stain) from gram negative bacteria. It does not remove Crystal violet as easily from gram positive bacteria, because the highly peptidoglycan walls of gram positive bacteria interact with crystal violet and iodine to form a strong bond (CV-Iodine complex). So, gram positive cells hold on to the stain instead of letting it wash away.
Are human cells gram positive?
Human cells are Gram-negative because they do not contain certain structures. More simply, if they don't have a cell wall they cannot be Gram-positive.
Biochemical tests to confirm micrococcus luteus?
I had a bacterial unknown of M. luteus in my microbiology lab. M. luteus is a Gram positive cocci (as seen by a gram stain). A good definitive test for Gram + cocci is the catalase test. M. luteus is catalase positive. Then a nitrate test can be performed to determine that M. luteus is nitrate negative. Those alone should be enough to confirm M. luteus.
Did you stain the bacterial cell wall or the cell cytoplasm?
Yes, it is. Using the Gram staining method, the wall can be seen.
What is fluorochrome staining technique for mycobacterium?
A flourochrome stain is an ultraviolet reactive dye that shines when exposed to UV. By using this stain, acid-fast bacilli (such as mycobacterium) can be easily seen. Flourochrome is used because standard techniques such as Gram stains can result in inconclusive results.
What are the differences between gram positive and gram negative bacteria?
The cell walls are the difference. Gram stain will be positive, as the cell wall is thicker. Gram-positive bacteria retain the (crystal violet) dye. Then a decolorizer will be added and then the pink counterstain. This will give all gram-negative bacteria a red or pink coloring. All the steps are done for all cultures being Gram stained and when they grow, the color will be seen as well as the shape.
What are the three basic Theories on the principle of gram staining reactions?
The gram stain is a basic differential stain used to determine if a bacterial cell is gram positive or negative. Gram positive cells have a thick peptidoglycan layer that will trap the crystal violet iodine crystalls and apear purple. Gram negative cells only have a thin peptidoglycan layer that allows the crystals to diffuse out of the cell and will only be seen with the application of a counterstain, such as safranin which turns the cells pink.
