Examples of Gram stain in the following topics:
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- Gram staining (or Gram's method; is a method of differentiating bacterial species into two large groups (Gram-positive and Gram-negative).
- A Gram positive results in a purple/blue color while a Gram negative results in a pink/red color.
- The Gram stain is almost always the first step in the identification of a bacterial organism, and is the default stain performed by laboratories over a sample when no specific culture is referred.
- While Gram staining is a valuable diagnostic tool in both clinical and research settings, not all bacteria can be definitively classified by this technique, thus forming Gram-variable and Gram-indeterminate groups as well.
- This is a microscopic image of a Gram stain of mixed Gram-positive cocci (Staphylococcus aureus, purple) and Gram-negative bacilli (Escherichia coli, red).
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- Gram-positive bacteria have cell envelopes made of a thick layer of peptidoglycans.
- Gram-positive bacteria are stained dark blue or violet by Gram staining .
- While Gram staining is a valuable diagnostic tool in both clinical and research settings, not all bacteria can be definitively classified by this technique, thus forming Gram-variable and Gram-indeterminate groups as well.
- A Gram-positive results in a purple/blue color while a Gram-negative results in a pink/red color.
- The Gram stain is almost always the first step in the identification of a bacterial organism, and is the default stain performed by laboratories over a sample when no specific culture is referred.
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- Examples of chemical assays include the classic test for Gram-positive or Gram-negative bacteria via Gram staining.
- Gram staining is utilized to differentiate bacteria into either of these Gram groups.
- The Gram staining technique is based on both chemical and physical properties of bacterial cell walls and tests for the presence of peptidoglycan.
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- Within prokaryotes, archaeal cell structure is most similar to that of Gram-positive bacteria.
- The Gram stain, developed in 1884 by Hans Christian Gram, characterizes bacteria based on the structural characteristics of their cell walls.
- The thick layers of peptidoglycan in the "Gram-positive" cell wall stain purple , while the thin "Gram-negative" cell wall appears pink.
- By combining morphology and Gram-staining, most bacteria can be classified as belonging to one of four groups (Gram-positive cocci, Gram-positive bacilli, Gram-negative cocci, and Gram-negative bacilli).
- Some organisms are best identified by stains other than the Gram stain, particularly mycobacteria or Nocardia, which show acid-fastness on Ziehl–Neelsen or similar stains.
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- Despite there being little agreement on the major subgroups of the Bacteria, gram staining results were commonly used as a classification tool.
- Until the advent of molecular phylogeny the Kingdom Prokaryotae was divided into four divisions, a classification scheme still formally followed by Bergey's manual of systematic bacteriology.The various species differ amongst each other based on several characteristics determined by gram staining, which allowed their identification and classification.
- Major groups of this system include: Gracilicutes (gram negative); Firmacutes (gram positive); Mollicutes (gram variable, e.g.
- Mycoplasma); and Mendocutes (uneven gram stain, "metlynogenic bacteria" now known as the Archaea).
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- According to the way their cell wall structure stains, bacteria can be classified as either Gram-positive or Gram-negative when using the Gram staining .
- This is a microscopic image of a Gram stain of mixed Gram-positive cocci (Staphylococcus aureus, purple) and Gram-negative bacilli (Escherichia coli, red).
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- The Firmicutes are a phylum of bacteria, most of which have Gram-positive cell wall structure and some of which do not produce spores.
- These are a phylum of bacteria, most of which have Gram-positive cell wall structure .
- A few, however, such as Megasphaera, Pectinatus, Selenomonas and Zymophilus, have a porous pseudo-outer-membrane that causes them to stain Gram-negative.
- A Gram-positive, catalase-positive bacterium which is rod-shaped, and has the ability to form a tough, protective endospore, allowing the organism to tolerate extreme environmental conditions.
- This is a microscopic image of Bacillus subtilis (ATCC 6633) with a gram staining of magnification: 1,000.
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- Direct microscope observation of a fresh or stained specimen is one of the most rapid methods of determining characteristics.
- Stains most often employed for bacteria are the gram stain, though they do not work on some organisms.
- From such isolates, clinical microbiologists obtain information about a pathogen's microscopic morphology and staining reactions, culture appearance, motility, oxygen requirements, and biochemical characteristics.
- Describe how direct microscope observation of a fresh or stained specimen is one of the most rapid methods of determining its characteristics
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- Gram Positive.
- Streptococcus pneumoniae is a Gram-positive bacterium that often lives in the throat of people who do not have pneumonia.
- Other important Gram-positive causes of pneumonia are Staphylococcus aureus and Bacillus anthracis.
- Gram Negative.
- In reality, they are "atypical" because they do not gram stain as well as gram-negative and gram-positive organisms.
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- Endospore formation is usually triggered by a lack of nutrients, and usually occurs in Gram-positive bacteria.
- Endospore formation is usually triggered by lack of nutrients, and usually occurs in Gram-positive bacteria.
- While the rest of a bacterial cell may stain, the endospore is left colorless.
- To combat this, a special stain technique called a Moeller stain is used.
- Another staining technique for endospores is the Schaeffer-Fulton stain, which stains endospores green and bacterial bodies red .