Why is it necessary to use an old culture of Bacillus for Endospore staining?
Why are older cultures typically used for endospore staining (A hint: why would a fresh young culture be inappropriate for endospore staining?)? Young culture of spore-forming microbes may not demonstrate any endospores b/c the vegetative cells may not have been subjected to sufficient stress to stimulate sporulation.
What does a positive result for the endospore stain indicate about the organism quizlet?
If you get a positive result for the spore stain, it indicates (barring contamination) that the organism produces spores.
Why do you suppose the acid fast stain is not as widely used as the Gram stain quizlet?
Why is the acid fast stain not as widely used as the gram stain? When is it more useful than the gram stain? very few bacteria are acid fast positive, so the test is less useful than a gram stain, which separates organisms into two large groups.
Why is it not necessary to include a negative control for this stain procedure?
why is it not necessary to include a negative control for the endospore stain procedure? because an endospore stain is a differential type of staining procedure. it allows us to see both spores and vegetative cells. therefore, including a separate negative control consisting of only vegetative cells isn't necessary.
How might the age of the culture affect the results of the endospore stain?
How does culture age affect the results of a spore stain? old cultures tend to have more spores, bacteria produce more endospores when they get older.
What is the appropriate age of the bacterial culture if you need to use spore stain technique?
between 18 and 36 hours old Using aseptic technique, smear a bacterial colony into the liquid to produce a thin, even layer. Note: Endospores generally do not form in young cells; therefore, the culture is recommended to be between 18 and 36 hours old (9).
What does a spore stain tell you?
This staining technique is known as the Endospore stain, also known as the spore stain. It is used majorly to detect and identify the presence of a bacterial endospore and bacterial vegetative forms in a cell. Examples of these endospore-forming bacteria include Clostridium spp and Bacillus spp.
Why do endospores do not stain easily?
Because of their tough protein coats made of keratin, spores are highly resistant to normal staining procedures. The primary stain in the endospore stain procedure, malachite green, is driven into the cells with heat.
Why is acid-fast not used as much as Gram stain?
The reason for weak Gram staining is that the outer membrane of the acid-fast cell wall contains large amounts of glycolipids, especially mycolic acids that in the genus Mycobacterium, make up approximately 60% of the acid-fast cell wall.
How does heating the bacterial smear during Zn stain promote entry of carbol Fuchsin into the acid-fast cell wall?
How does heating the bacterial smear during a ZN stain promote entry of carbolfuchsin into the acid-fast cell wall? Heating melts the mycolic acid and allows the stain to penetrate the cell walls.
Why are cultures 48 hours and older used to test for endospores?
1. Why does this exercise call for an older (48-hour or 5-day) culture of Bacillus? –Young cultures of spore-forming microbes may not demonstrate any endospores because the vegetative cells may not have been subjected to sufficient stress to stimulate sporulation.
Why do you need positive and negative control samples as well as your experimental samples?
The importance of including ELISA controls, both positive and negative, in your immunoassay helps to verify that the assay was run properly and everything is performing accurately.
What might affect the results of the endospore stain?
How does the culture affect the results of an endospore stain? If the culture is a harsh environment there would be more spores than vegetative cells. The same goes vise-versa.
Why is using cultures older than 24 hours not advisable in Gram staining method?
Old cultures tend to lose the peptidoglycan cell walls, which predisposes gram-positive cells to be gram-negative or gram variable.
Why does culture age affect the results of a spore stain?
How does culture age affect the results of a spore stain? old cultures tend to have more spores, bacteria produce more endospores when they get older.
What diseases can be diagnosed with the endospore stain?
Infectious diseases such as anthrax, tetanus, gas gangrene, botulism, and pseudomembranous colitis are transmitted to humans by endospores.
What does a positive spore stain results indicate about an organism?
a. What does a positive result for the endospore stain indicate about the organism? -If you get a positive result for the endospore stain, it indicates (barring contamination) that the organism produces spores.
Are Bacillus acid-fast?
Acid-fast bacillus (AFB) is a type of bacteria that causes tuberculosis and certain other infections. Tuberculosis, commonly known as TB, is a serious bacterial infection that mainly affects the lungs. It can also affect other parts of the body, including the brain, spine, and kidneys.
Why acid-fast bacilli are called acid-fast?
Acid-fast bacteria, also known as acid-fast bacilli or simply AFB, are a group of bacteria sharing the characteristic of acid fastness. Acid fastness is a physical property that gives a bacterium the ability to resist decolorization by acids during staining procedures.
Why does the bacterial smear needs to be heated when performing acid-fast staining and spore staining?
The heat “melts” the waxy cell wall and permits the absorption of the dye by the cells. Then the slide is allowed to cool and a solution of acid and alcohol is added as a decolorizer.
Why is the Ziehl neelsen method called the hot method while the kinyoun method the cold method?
The Ziehl-Neelsen method of staining is also called the hot method as it involves heating the carbolfuchsin stain. In contrast, the historic method of staining called the Kinyoun method does not involve heating and is hence known as the cold method. Currently, the cold method is already obsolete.
Why was a 48 hour culture of B subtilis used rather than a fresh culture for the endospore stain?
Why is a 48 hour culture required for an endospore stain? Endospores form under environemental stress. If you wait 48 hours, the bacteria will be lacking nutrients.
Why should a positive and a negative control be included along with patient samples when performing an ELISA?
The importance of including ELISA controls, both positive and negative, in your immunoassay helps to verify that the assay was run properly and everything is performing accurately.
Why is it important to include negative and positive controls when performing a test?
Negative controls are particular samples included in the experiment that are treated the same as all the others but are not expected to change from any variable in the experiment. The positive control sample will show an expected result, helping the scientist understand that the experiment was performed properly.
How does the age of a bacterial culture affect the interpretation of a Gram stain reaction?
how does the age of a culture affect the gram stain reaction? what is an optimum culture age for a valid gram reaction? old cultures of gram positive cells may not retain stain as well as younger cultures and could give false negative results (ex) pink cells. Cultures that are 16-18 hrs are best.
Why does the age of the bacterial culture matter for Gram staining?
what is an optimum culture age for a valid gram reaction? old cultures of gram positive cells may not retain stain as well as younger cultures and could give false negative results (ex) pink cells. Cultures that are 16-18 hrs are best.
Why do gram-positive cells more than 24 hours old stain gram-negative?
Why do gram-positive cells more than 24 hours old stain gram-negative? Because the cell wall begins to deteriorate and change.
What is the purpose of Bacillus structure?
The cell wall of Bacillus is a structure on the outside of the cell that forms the second barrier between the bacterium and the environment, and at the same time maintains the rod shape and withstands the pressure generated by the cell's turgor.
Does Bacillus produce endospores?
Examples of bacteria that can form endospores include Bacillus and Clostridium. The endospore consists of the bacterium's DNA and part of its cytoplasm, surrounded by a very tough outer coating. Endospores can survive without nutrients.
Why is bacilli called acid-fast?
Acid-fast bacteria, also known as acid-fast bacilli or simply AFB, are a group of bacteria sharing the characteristic of acid fastness. Acid fastness is a physical property that gives a bacterium the ability to resist decolorization by acids during staining procedures.