Why stain bacteria?
Bacteria is stained to identify the organism and its structure. Staining also can help in identification of a species. Bacteria are translucent in appearance therefore a stain is applied to allow them to become visible.
Bacteria are gram positive or gram negative. Serratia happens to be a gram negative bacteria. They appear pink on a gram stain. Gram positive bacteria stain to a purple color on a gram stain. We can classify and ID bacteria using their gram stain and shape. Some antibiotics only work on gram negative bacteria and some only work on gram positive bacteria. It helps a doctor know which antibiotic to use.
What is the difference between a simple and a differential stain? A simple stain depends on the fact that bacteria differ chemically from their surroundings and thus can be stained with their environments. A differential stain can distinguish betweeen 2 types of bacteria because bacteria differ from one another chemically & physically to react differently to a given staining procedure.
Yes. The gram stain procedure separates all bacteria into one of two groups - into gram-negative bacteria which do not stain purple and into gram-positive cells which do stain purple. In structural terms, the ability of a cell to become stained during the gram stain procedure is due to the chemical makeup of the cell wall.
The decolorizing agent makes sure that the cells that are not supposed to retain the first stain, actually do release it so that the second stain can show the difference. For example when doing a Gram Stain, the first stain is the crystal-violet stain which is retained by the gram-positive bacteria. If the decolorizer isnt applied though, then the gram-negative bacteria will also hold onto the crystal violet stain and then you wont be able…
Actinomyces: cause respiratory diseases and cavities. Bacillus: anthrax and food poisoning. Clostridium: tetanus, food poison, gas gangrene and botulism. Corynebacterium: diphtheria. Gardnerella: vaginitis. Lactobacillus: vaginal flora. Listeria: newborn meningitis. Mycobacterium: leprosy and tuberculosis. Mycoplasma: walking pneumonia. Propionibacterium: acne. Staphylococcus: Methicillin Resistant Staph aureus (MRSA) and Vancomycin Resistant Staph aureus (VRSA).Streptococcus: pneumonia and cavities.
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.
Why is it necessary to excessively rinse the smear with water in experiment identifying bacteria using gram stain?
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.
When we stain bacteria we use a substance called Gram's stain. The bacteria take up the red or the purple in the stain depending on their type. Gram positive bacteria picks up the purple portion in the gram stain and the gram negative pick up the red color of the stain. As an example, Staphylococcus and Streptococcus are gram positive bacteria while E. which is the most common bacteria in urinary tract infections are gram…
Why is counterstaining necessary when using a differential staning technique such as the gram stain?
On the basis of cell wall, bacteria can be divided in to Gram's positive or negative bacteria. Those stained by primary stain are positive while those which are not stained by primary stain are subjected to counterstain that is safranin and are known as Gram's negative bacteria, safranin gives pink or red color to Gram's negative bacteria and helps differentiating them from Gram positive bacteria which are have a violet or purple color due to…
No, the Gram stain is a differential stain which classifies bacteria as either gram-positive or gram negative. The cell is first stained with a primary stain such as crystal violet.All bacteria are stained purple by this basic dye. after that a mordant(Grams iodine) is applied. Next a decolorizing agent (ethanol or ethanol-acetone)is applied. The primary stain is washed out(decolorized) of some bacteria(Gram -Neg),whereas others are unaffected(Gram-Pos).A secondary or counterstain such as safranin is applied, this…
Gram positive bacteria stain purple with the Gram stain. This is because of the fact that they contain a thick layer of murein in their cell wall, which takes up the stain very well. Gram negative bacteria, however, do not display the thick layer of peptidoglycan on their outer surface. Therefore, they stain red with the counter stain.
Gram variability of bacteria is a function of the cell wall composition. For gram positive bacteria (they stain in violet!) the cell wall is composed of peptidoglycan and they do not have a lipopolysaccharide layer above this peptidoglycan layer. Gram negative bacteria (stain pink!) have a lipopolysaccharide layer above the peotidoglycan layer which do stain violet with crystal violet, but are washed off by the ethanol treatment. The peptidoglycan layer beneath remains untouched by the…
gram staining differentiates between gram negative and gram positive bacteria by showing different colors. it shows blue or purple like color for gram positive bacteria and red color for gram negative bacteria. where as simple stain gives the same color to all the types of bacteria. hence it is difficult to differentiate between them.
Simple stain , is just used to bring the bacteria from the fore ground so you can see it better, and it's heat fix so it's no longer alive. Differential stain, is also heat fix, but you used Crystal violet which binds to the cell wall of the bacteria that have a thick cell wall, and Iodine is used as a mordant too help crystal violet attach to the cell wall, the counter stain is…
What is there in the structure of bacteria that causes some to stain purple and others to stain red?
The purple stained bacteria are called gram positive bacteria and retain the stain after washing by having a thick cell wall one one layer of a heavily crossed linked material called peptidoglycan. ( Google that ) The red stained bacteria are gram negative because they posses two thinner layers of peptidogylcan cell wall that that do not hold the gram stain and it is mostly washed away in rinsing the bacterial samples.