Last updated on June 7th, 2021Capsule stain is a type of differential stain which uses acidic and basic dyes to stain background & bacterial cells respectively so that presence of capsule is easily visualized. Capsule is […]
Last updated on May 30th, 2021Streptococcus pyogenes is the leading cause of uncomplicated bacterial pharyngitis and tonsillitis commonly referred to as strep throat. Acute diseases associated with Streptococcus pyogenes occur chiefly in the respiratory tract (sinusitis, otitis), bloodstream (sepsis, endocarditis, meningitis), or theskin (impetigo, […]
Last updated on June 12th, 2021The cell wall of Gram-negative bacteria is more complex than those of Gram-positive bacteria. Gram-negative bacteria contain an extra layer of cells called outer membrane or lipopolysaccharide (LPS) layer which […]
Last updated on June 3rd, 2021The term peptidoglycan was derived from the peptides and the sugars (glycan) that make a molecule; it is also called ‘murein’ or ‘mucopeptide’. This is a complex interwoven network of […]
Last updated on June 1st, 2021Transposons are mobile genetic elements that are found in almost all organisms. Scientists believe that transposons make up more than 40% of the human genome. They are also referred to […]
Last updated on May 30th, 2021Concentrated deposits of certain substances which are presented/located in the cytoplasm of certain bacteria are known as cytoplasmic granules or inclusion bodies. They serve as storage areas for nutrients, e.g. […]
Last updated on June 3rd, 2021Many gram-positive bacteria have acidic components called teichoic acids embedded in their cell wall. Teichoic acids were discovered in 1958 by Armstrong and co-authors. The term teichoic acid encompasses a […]
Last updated on May 30th, 2021Lipopolysaccharide (LPS) layer also called the outer membrane is the outermost layer present in the cell wall of gram-negative bacteria. It is a characteristics feature of Gram-negative bacteria. As in […]
Last updated on May 30th, 2021Found mainly in Gram-negative organisms, fimbriae or pili (singular: pilus) are hair-like filaments (tiny hollow projections) that extend from the cell membrane into the external environment. A pilus is composed […]
Last updated on May 30th, 2021Flagella (singular, flagellum) are the locomotory structures of many prokaryotes. The flagellum functions by rotation to push or pull the cell through a liquid medium. Bacterial Flagella Bacterial flagella are […]
Last updated on May 29th, 2021Bacterial spores are highly resistant, dormant structures (i.e. no metabolic activity) formed in response to adverse environmental conditions. They help in the survival of the organisms during adverse environmental conditions; […]
Last updated on June 1st, 2021Capsule (also known as K antigen) is a major virulence factor of bacteria, e.g. all of the principal pathogens which cause pneumonia and meningitis, including Streptococcus pneumoniae, Haemophilus influenzae, Neisseria […]
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