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Why would you want to know if a gram stain is positive or negative?
Gram negative bacteria (pink gram stain) contain no outer cell membrane, while gram positive bacteria (purple gram stain) do contain an outer cell membrane. Gram negative and positive bacteria can respond differently to antibiotics. Many only work on only one of the two bacteria types. A gram stain is also the first step in identifying a bacteria, dividing bacteria into two large and distinct groups.
What would be the appearance of the gram positive bacterium if you forget to counterstain with safranin?
If you forget to counter stain color of Gram positive would be violet or blue . The above answer is good. Here is why the above answer is good. Yes it would still be Violet or blue. Gram positive bacteria are gram positive, because it holds onto the crystal violet stain that washes out of gram negative bacteria. Counterstaining with safranian turns gram negative bacteria pink to red only because the crystal violet has washed out of the gram negative. The lighter safranian has little to no effect on gram positive bacteria. The cause of the difference has to do with the makeup of the cell wall in the different bacteria.
How do you isolate and identify gram positive cocci?
I'm not sure exactly what you are asking. How would a person stain cocci? What makes cocci gram positive? Or how would a person g How does a person contract gram cocci
Why is counterstaining necessary when using a differential staning technique such as the gram stain?
The counter-stain allows you to see all the structures that were not stained with the primary stain. Without the counter-stain, all you would see is the purple-stained structures (nucleus, some cytoplasmic proteins), but you would have a difficult time observing the cell membrane and many cytoplasmic structures.
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.
Why would you want to know if a gram stain is positive or negative?
Gram negative bacteria (pink gram stain) contain no outer cell membrane, while gram positive bacteria (purple gram stain) do contain an outer cell membrane. Gram negative and positive bacteria can respond differently to antibiotics. Many only work on only one of the two bacteria types. A gram stain is also the first step in identifying a bacteria, dividing bacteria into two large and distinct groups.
What would be the appearance of the gram positive bacterium if you forget to counterstain with safranin?
If you forget to counter stain color of Gram positive would be violet or blue . The above answer is good. Here is why the above answer is good. Yes it would still be Violet or blue. Gram positive bacteria are gram positive, because it holds onto the crystal violet stain that washes out of gram negative bacteria. Counterstaining with safranian turns gram negative bacteria pink to red only because the crystal violet has washed out of the gram negative. The lighter safranian has little to no effect on gram positive bacteria. The cause of the difference has to do with the makeup of the cell wall in the different bacteria.
Methylene blue can be prepared as a basic stain or an acidic stain. How would the pH affect the staining of bacteria?
# The pH will determine if the bacteria will have a particular charge. If the chromophore is a positive ion like the methylene blue in the equation shown in the reading, the stain is considered a basic stain; if it is a negative ion, it is an acidic stain. Most bacteria are stained when a basic stain permeates the cell wall and adheres by weak ionic bonds to the negative charges of the bacterial cell.
Why is the gram stain technique more valuable than the simple stain technique in the diagnostic laboratory Under what circumstances might the simple stain be preferable to the gram stain technique?
There are two types of stains, the simple stain and the differential stain. A simple stain colors all objects the same while a differential stain is used to spot differences in microorganisms. A gram stain is a differential stain, which is used to tell the difference in gram negative and gram positive bacteria. A simple stain would stain all the organisms the same and this difference would not be noted. You would be able to determine their shape, whether it is a cocci or bacillus (rod), but not the type. I'm not sure why the simple stain would be preferable unless you just wanted a quick answer as to the shape of the bacteria. In some cases, a wet prep can be made of a presumptive gram positive cocci to tell the difference between bacteria or yeast. Otherwise, I would say that the gram stain is the only way to go.
How do you isolate and identify gram positive cocci?
I'm not sure exactly what you are asking. How would a person stain cocci? What makes cocci gram positive? Or how would a person g How does a person contract gram cocci
Does a micrococcus luteus is positive for capsule stain?
yes as it have capsule it give positive test for capsule staining when stain with malachite green The problem with the above answer is that a capsule stain is NOT done with malachite green.
Why is counterstaining necessary when using a differential staning technique such as the gram stain?
The counter-stain allows you to see all the structures that were not stained with the primary stain. Without the counter-stain, all you would see is the purple-stained structures (nucleus, some cytoplasmic proteins), but you would have a difficult time observing the cell membrane and many cytoplasmic structures.
Which stain would be the best choice for detecting mycobacterium the bacteria responsible for tuberculosis and leprosy?
ZN 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.
What is the purpose of staining an unknown organism?
By doing differential stains on an unknown organism, you can learn more about that organism. One of the most helpful stains would be the Gram stain. The gram stain will differentiate from Gram positive and Gram negative cells, narrowing your bacteria down a lot. Other stains include: Acid-Fast stain, Capsule stain, Endospore stain, and PHB stain.
What would happen if you decolorized your slide too much on a gram stain?
The purpose of any microbiological stain (gram or otherwise), is to enable visualization of features that would otherwise be clear/invisible in a sample. In this case, the darker crystal violet is used to stain the peptidoglycan cell walls of gram-positive bacteria. Washing the sample with too much ethanol (decolorizing too much) will remove too much stain, making it difficult or impossible to distinguish between gram-negative and gram-positive cells. Only the counterstain that is added after the ethanol wash (safranin, for example) will be visible.(see related links for example descriptions of Gram staining)
How would you describe the gram stain?
Describe the Gram stain technique and the effect on Gram-positive and Gram-negative bacteria after each step. Be very specific about what is happening at each step and why it happens. (hint: be sure to fully explain your answer and not just list the steps)
