gram-positive
/'græm'pɔzətiv/
Học thuậtThân thiện
Definition
- Adjective:
- Relating to bacteria that stain violet in Gram's method: Describes bacteria that retain the primary crystal violet stain during the Gram staining procedure, due to the thick peptidoglycan layer in their cell walls.
Usage
- Adjective:
- This term is used to classify bacteria based on their cell wall structure and staining characteristics.
- It is primarily used in scientific, medical, and microbiological contexts.
Examples
- Adjective:
- Staphylococcus aureus is a common gram-positive bacterium.
- The laboratory report identified the infection as being caused by a gram-positive coccus.
- Penicillin is often effective against many gram-positive organisms.
Advanced Usage
- "Gram-positive cocci": A common phrase in microbiology specifying the shape (spherical) of the bacteria.
- The blood culture grew gram-positive cocci in clusters.
- "Gram-positive rod": A phrase specifying a rod-shaped, gram-positive bacterium.
- Bacillus anthracis is a gram-positive rod.
Variants and Related Words
- Gram-negative (adj): The contrasting category; bacteria that do not retain the crystal violet stain and instead take up a counterstain (appearing pink or red).
- Escherichia coli is a gram-negative bacterium.
- Gram stain (n): The differential staining technique developed by Hans Christian Gram.
- The Gram stain is a fundamental test in microbiology.
Synonyms
- There are no direct synonyms for this specific scientific classification. The term is precise and standard.
Related Phrases
- Gram reaction: The staining characteristic (positive or negative) of a bacterium.
- The Gram reaction is the first step in bacterial identification.
- Gram-variable: Describing bacteria that stain inconsistently or show a mix of positive and negative reactions.
- Some Actinomyces species can exhibit a gram-variable reaction.
Adjective
- (of bacteria) being or relating to a bacterium that retains the violet stain used in Gram's method