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Yes, the age of the culture may influence the results of the stain.
With the current theory behind gram staining, it is thought that in gram-positive bacteria, the crystal violet and iodine combine to form a larger molecule that precipitates out within the cell. The alcohol/acetone mixture then causes dehydration of the multilayered peptidoglycan in the gram-positive call wall, thus decreasing the space between the molecules and causing the cell wall to trap the crystal violet-iodine complex within the cell. In the case of gram-negative bacteria, the alcohol/acetone mixture, being a lipid solvent, dissolves the outer membrane of the gram-negative cell wall (and may also damage the cytoplasmic membrane to which the peptidoglycan is attached). The thin layer of peptidoglycan is unable to retain the crystal violet-iodine complex and the cell is decolorized.
It is important to note that gram-positivity (the ability to retain the purple crystal violet-iodine complex) is not an all-or-nothing phenomenon but a matter of degree. There are several factors that could result in a gram-positive organism staining gram-negatively:
1. The method and techniques used. Overheating during heat fixation, over decolorization with alcohol, and even too much washing with water between steps may result in gram-positive bacteria losing the crystal violet-iodine complex.
2. The age of the culture. Cultures more than 24 hours old may lose their ability to retain the crystal violet-iodine complex.
3. The organism itself. Some gram-positive bacteria are more able to retain the crystal violet-iodine complex than others.
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∙ 11y ago
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∙ 15y agoVery young and very old cells often produce poor results. cells that are healthy and growing optimally, tend to give dependable results
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∙ 14y agohi i am the blackfoot. are maie food was the bufflo. the wenmen main role was to
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∙ 13y agoThe age of the microbe can give the Gram stain a false negative if the microbe is too old.
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Why would bacteria stain gram variable?
A gram-negative cell will lose its outer membrane and the peptidoglycan layer is left exposed. or it is best to use younger cells ( 12-24hr) because older gram positive bacteria are subject to break down of the cell wall by enzymes that are produced with age which may result ingram variable staining.
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.
How does culture age affect the results of a sproe stain?
Spores are formed when cells are under unfavourable conditions, as for the bacteria they are means of survival. So the older the culture the higher the cell number in that culture, which means less nutrients for the cells. Under this conditions cells will start spore production. Depending on the "age" of the culture you can get a mixture of vegetative cells with spores inside and spores that are already released or mostly spores with rare vegetative cells, which means the cells are dead.
Why are older bacterial cells more easily decolorized than younger colonies?
OIder bacteria cells are decolorized more easily than younger cells, because as cells age their cell walls become "leaky" and allow molecules to pass more readily out of the cell. In gram stain, the crystal violet-iodine complex is more readily lost during the decolorization step.
What effect does age have on your sensitivity to various smell?
Age will affect your sense of smell, taste and hearing. Age will decrease sensitivity of senses.
You preformed a gram stain on a sample from a pure culture of bacteria and observed a field of red and purple cocci adjacent cells were not always the same color what do you conclude?
This is a Gram Stain. If the technique was proper, the red rods are Gram-negative and the purple cocci are Gram-positive. This staining technique is used to help identify various bacteria. The Gram-positive bacteria that are purple hold the stain due to it's layered cell membrane. It contains a peptidoglycan layer that acts as a lattice trapping the crystal violet-Iodine dye complex.
How does culture age affect results of a spore stain?
Older cultures produce more spores. If the culture is not old enough, the spores will be few, and possibly undetectible.
What are advantages and disadvantages of staining a sample?
Some cells produce gram-variable results. Some cells produce no results. The age of the culture can influence the results. It has limited usage in environmental biology and is not as good as molecular techniques.
What are the factors that can result in variable gram reaction?
Genetics, Age of culture, type of growth medium, and technique used could result in a gram-variable reaction
Why would bacteria stain gram variable?
A gram-negative cell will lose its outer membrane and the peptidoglycan layer is left exposed. or it is best to use younger cells ( 12-24hr) because older gram positive bacteria are subject to break down of the cell wall by enzymes that are produced with age which may result ingram variable staining.
Why do gram negative cells stain pink?
Gram negative bacteria actually stain red because they have a less complex cell wall than Gram positive bacteria and they are easily decolorised by the decoloriser acetone alcohol. Hence they take up the colour of the counter stain safranin which is red during the Gram staining procedure.
Why must fresh bacterial cultures be used in a Gram stain?
Why must young cultures be used when doing a Gram stain Young cultures must be used so the crystal violet can stick to the cell walls of Gram positive bacteria. The cell walls break down in old cultures and the staining process is not accurate
Three factors that may affect gram stain reaction?
(i) The age of bacterial culture should not be more than 24 h. At older age cell loses Gram positivity and will appear as Gram negative. (ii) Application of heat during the fixation of smears is another important step. Too much heating during this step will lead to loss in, Gram positiveness. (iii) Overcrowding of cells in smear also affects the result, due to improper decolourization. (iv) Staining reagents should be freshly prepared. (v) In Gram staining decolourizing step is very important. To obtain satisfactory differentiation, the nature and the exposure time of decolourizing agent should be standardized with the material to be stained. Acetone alone is more powerful decolourizing agent than ethanol. (vi) It is also important not to allow a .bacterial smear to dry. There are many variations of original Gram staining procedure
Does the age of the culture affect the gram stain?
Yes, the age of the culture may influence the results of the stain. With the current theory behind gram staining, it is thought that in gram-positive bacteria, the crystal violet and iodine combine to form a larger molecule that precipitates out within the cell. The alcohol/acetone mixture then causes dehydration of the multilayered peptidoglycan in the gram-positive call wall, thus decreasing the space between the molecules and causing the cell wall to trap the crystal violet-iodine complex within the cell. In the case of gram-negative bacteria, the alcohol/acetone mixture, being a lipid solvent, dissolves the outer membrane of the gram-negative cell wall (and may also damage the cytoplasmic membrane to which the peptidoglycan is attached). The thin layer of peptidoglycan is unable to retain the crystal violet-iodine complex and the cell is decolorized. It is important to note that gram-positivity (the ability to retain the purple crystal violet-iodine complex) is not an all-or-nothing phenomenon but a matter of degree. There are several factors that could result in a gram-positive organism staining gram-negatively: 1. The method and techniques used. Overheating during heat fixation, over decolorization with alcohol, and even too much washing with water between steps may result in gram-positive bacteria losing the crystal violet-iodine complex. 2. The age of the culture. Cultures more than 24 hours old may lose their ability to retain the crystal violet-iodine complex. 3. The organism itself. Some gram-positive bacteria are more able to retain the crystal violet-iodine complex than others.
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.
If iodine step missed in gram stain what will happen?
Iodine (I - or I3 - ) interacts with CV+ and forms large complexes of crystal violet and iodine (CV-I) within the inner and outer layers of the cell. Iodine is often referred to as a mordant, but is a trapping agent that prevents the removal of the CV-I complex and, therefore, color the cell.[10]
Does the age of the culture affect the gram staining reaction?
Yes, the age of the culture may influence the results of the stain. With the current theory behind gram staining, it is thought that in gram-positive bacteria, the crystal violet and iodine combine to form a larger molecule that precipitates out within the cell. The alcohol/acetone mixture then causes dehydration of the multilayered peptidoglycan in the gram-positive call wall, thus decreasing the space between the molecules and causing the cell wall to trap the crystal violet-iodine complex within the cell. In the case of gram-negative bacteria, the alcohol/acetone mixture, being a lipid solvent, dissolves the outer membrane of the gram-negative cell wall (and may also damage the cytoplasmic membrane to which the peptidoglycan is attached). The thin layer of peptidoglycan is unable to retain the crystal violet-iodine complex and the cell is decolorized. It is important to note that gram-positivity (the ability to retain the purple crystal violet-iodine complex) is not an all-or-nothing phenomenon but a matter of degree. There are several factors that could result in a gram-positive organism staining gram-negatively: 1. The method and techniques used. Overheating during heat fixation, over decolorization with alcohol, and even too much washing with water between steps may result in gram-positive bacteria losing the crystal violet-iodine complex. 2. The age of the culture. Cultures more than 24 hours old may lose their ability to retain the crystal violet-iodine complex. 3. The organism itself. Some gram-positive bacteria are more able to retain the crystal violet-iodine complex than others.
