8
lol, we must be in the same class, b/c i have all of the same questions. did u figure out the answer? I think its a base ... qc the microbiology lab Cute, from the best that I could find some sources say pH 7 and others had given a pH 8. But could not find a solid answer. As a simple stain it would have to have a pH of <7. As we know, the charge on the cell is always going to be negative (an anion). In order to achieve a simple stain we want the stain attracted to the cell wall; therefore, the stain must be positively charged (a cation) for the opposite forces to attract. The more acidic the compound - the smaller its pH number with 7 being neutral. As we know, the [H]+ increases as the pH decreases becoming evermore positively charged. Simple answer: <7
it is used in diagnostic microscopy (to visualize the edges of protein complexes, macromolecules and cells in suspension).
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.
Because the cell wall repels the binding of the negative stain therefore the cells do not stain. Because of this the background is stain with the dye used and the bacteria remain colorless. Basically your staining the background, that is, you are not directly staining the cells.
A negative result for the spores stain indicate that the gram-negative organism is present. A positive result for a spore stain indicates that a gram positive organism is present.
lol, we must be in the same class, b/c i have all of the same questions. did u figure out the answer? I think its a base ... qc the microbiology lab Cute, from the best that I could find some sources say pH 7 and others had given a pH 8. But could not find a solid answer. As a simple stain it would have to have a pH of <7. As we know, the charge on the cell is always going to be negative (an anion). In order to achieve a simple stain we want the stain attracted to the cell wall; therefore, the stain must be positively charged (a cation) for the opposite forces to attract. The more acidic the compound - the smaller its pH number with 7 being neutral. As we know, the [H]+ increases as the pH decreases becoming evermore positively charged. Simple answer: <7
it is used in diagnostic microscopy (to visualize the edges of protein complexes, macromolecules and cells in suspension).
Since there is no heat fixing or strong cemicals are used the bacteria are less distorted
Negative staining has a dark contrasted background and the bacteria is white. Simple staining has a white background and bacteria is the color depended on your stain color.Negative staining when prepared is NOT heat fixed but simple staining when prepared is heat fixed. Heat fixed means when preparing slide with bacteria on it, it is passed over some type of flame, like a Bunsen burner flame, three times or four times.
Yes, uranyl acetate is used as a negative stain in electron microscopy.
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.
Because the cell wall repels the binding of the negative stain therefore the cells do not stain. Because of this the background is stain with the dye used and the bacteria remain colorless. Basically your staining the background, that is, you are not directly staining the cells.
A negative result for the spores stain indicate that the gram-negative organism is present. A positive result for a spore stain indicates that a gram positive organism is present.
Methylene blue
Pink Dye
B. subtilis is indeed a Gram positive rod.However, there is confusion as to whether it is an obligate aerobe or a facultative anaerobe. Although classed as an obligate aerobe, it has been shown to grow under strict anaerobic conditions.
Because negative staining requires the use of an acidic stain, which will not penetrate the cells because of the negative charge on the surface of the bacteria. As a result, the unstained cells can be easily identified against the colored background.