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what are some of the reasons for a gram-variable reaction
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What is gram variable bacilli?
Gram-variable bacilli are rod-shaped bacteria that do not consistently take up Gram stain, appearing either Gram-positive or Gram-negative under a microscope. This variability can result from factors such as the age of the culture, the composition of the cell wall, or the presence of certain conditions during staining. Gram-variable bacilli can include various species, some of which are pathogenic and associated with human diseases. Examples include certain strains of Corynebacterium and Mycobacterium.
What are 2 conditions in which an organism might stain gram variable?
An organism might stain gram variable due to the presence of a cell wall structure that is intermediate between gram-positive and gram-negative bacteria, often seen in some members of the Actinobacteria or Firmicutes phyla. Additionally, factors such as the age of the culture, where older cells may lose their ability to retain the crystal violet stain, or exposure to certain environmental stresses, such as changes in temperature or pH, can also lead to a gram variable result.
How does a gram variable organisms appear under the microscope?
Gram-variable organisms can appear inconsistently colored under a microscope after a Gram stain procedure. Some cells may take up the crystal violet stain and appear purple (Gram-positive), while others may not retain the stain and appear pink (Gram-negative) after the counterstain (safranin) is applied. This variability can be due to differences in cell wall structure or damage to the cells. Consequently, a mixed population of purple and pink cells can be observed in the same sample.
Can e coli be gram variable?
Escherichia coli (E. coli) is typically classified as a Gram-negative bacterium, meaning it usually stains pink in the Gram staining procedure due to its thin peptidoglycan layer and outer membrane. However, in certain conditions or due to cellular stress, some E. coli strains may exhibit Gram-variable characteristics, appearing both pink and purple. This variability can be influenced by factors such as age of the culture, environmental conditions, or specific strain characteristics. Despite these occasional variations, E. coli is primarily recognized as a Gram-negative organism.
What is the difference between Jensen's version ang hucker's modification in gram staining based on reagents and gram reaction to fungi?
What is modified in Jensen's modification of Gram stain? Jensen's modification: This method involves use to methyl violet as primary stain, iodine and potassium iodide in water as mordant, absolute alcohol as decolorizer and neutral red as counterstain
Does a variable change in an experiment?
some of them doesindependent variable doesdependent variable doesconstants variable do not
Does a variable change in a experiment?
some of them doesindependent variable doesdependent variable doesconstants variable do not
What are some examples of a scientific variable?
Some examples of a scientific variable is Independent Variable Control Variables :)
What are some words for gram?
The word gram is derived from the Greek gramma, meaning a small weight.
If your organisms were all blue with pink spots what is the Gram reaction if your organisms were all pink but had some blue spots what is the Gram reaction?
Gram positive cells take up the crystal violet, which is then fixed in the cell with the iodine mordant. This forms a crystal-violet iodine complex which remains in the cell even after decolorizing. It is thought that this happens because the cell walls of gram positive organisms include a thick layer of protein-sugar complexes called peptidoglycans. This layer makes up 60-90% of the gram positive cell wall. Decolorizing the cell causes this thick cell wall to dehydrate and shrink, which closes the pores in the cell wall and prevents the stain from exiting the cell. At the end of the gram staining procedure, gram positive cells will be stained a purplish-blue color. Gram negative cells also take up crystal violet, and the iodine forms a crystal violet-iodine complex in the cells as it did in the gram positive cells. However, the cell walls of gram negative organisms do not retain this complex when decolorized. Peptidoglycans are present in the cell walls of gram negative organisms, but they only comprise 10-20% of the cell wall. Gram negative cells also have an outer layer which gram positive organisms do not have; this layer is made up of lipids, polysaccharides, and proteins. Exposing gram negative cells to the decolorizer dissolves the lipids in the cell walls, which allows the crystal violet-iodine complex to leach out of the cells. This allows the cells to subsequently be stained with safranin. At the end of the gram staining procedure, gram negative cells will be stained a reddish-pink color. Remember:
Why is yoga an independent variable?
Yoga can be an independent variable in some experiments and a dependent variable in others.
Is electricity a variable or semi-variable cost?
If electricity expense is dependant on production level then it is variable expenses other wise some of expenses may be of variable nature while some part is fixed or semi variable nature as well.
