Capsule Stain- Principle, Procedure and Result Interpretation

A capsule is a gelatinous outer layer that is secreted by the cell and that surrounds and adheres to the cell wall. It is not common to all organisms. Cells that have a heavy capsule are generally virulent and capable of producing disease, since the structure protects bacteria against the normal phagocytic activities of host cells. Chemically, the capsular material …

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Negative Staining- Principle, Procedure and Result Interpretation

Negative Staining- Principle, Procedure and Result Interpretation

Objectives of Negative Staining To perform a negative staining procedure. To understand the benefit obtained from visualizing unstained microorganisms. Principle of Negative Staining Negative staining requires the use of an acidic stain such as India ink or nigrosin. The acidic stain, with its negatively charged chromogen, will not penetrate the cells because of the negative charge on the surface of …

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Simple Staining- Principle, Procedure and Result Interpretation

Simple Staining- Principle, Procedure and Result Interpretation

Objectives of Simple Staining To perform a simple staining procedure. To compare the morphological shapes and arrangements of bacterial cells. Principle of Simple Staining In simple staining, the bacterial smear is stained with a single reagent, which produces a distinctive contrast between the organism and its background. Basic stains with a positively charged chromogen are preferred because bacterial nucleic acids and certain …

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Acridine Orange Stain- Principle, Procedure and Result Interpretation

Acridine Orange Stain- Principle, Procedure and Result Interpretation

Objective Differential staining of nucleic acids including DNA and RNA. Principle Acridine orange, a vital stain, will intercalate with nucleic acid, changing the dye’s optical characteristics so that it will fluoresce bright orange under ultraviolet light. All nucleic acid–containing cells will fluoresce orange. Acridine orange is a metachromatic stain and under appropriate conditions, RNA will stain orange and DNA will …

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Acid Fast Stain (Kinyoun-Cold Method)- Principle, Procedure and Result Interpretation

Acid Fast (Kinyoun-Cold Method)- Principle, Procedure and Result Interpretation

Objective of Kinyoun-Cold Method Identification of acid-fast Mycobacterium spp. and parasites such as Cryptosporidium and Isopora spp. Principle of Kinyoun-Cold Method Acid-fast mycobacteria contain mycolic acid in their outer membrane, making the cells waxy and resistant to staining with aqueous based stains such as the Gram stain. The primary stain, carbolfuchsin, is applied to the cells and phenol is used to allow …

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Acid Fast Stain- Principle, Reagents, Procedure and Result Interpretation

Acid Fast Stain- Principle, Reagents, Procedure and Result Interpretation

It is also know as Ziehl-Neelsen stain. Objective of Acid Fast Stain The main aim objective of this stain is to differentiate bacteria into acid fast group and non-acid fast groups. Principle of Acid Fast Stain Acid-fast mycobacteria contain mycolic acid in their outer membrane, making the cells waxy and resistant to staining with aqueous based stains such as the Gram …

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Bile Esculin Test- Principle, Procedure and Result Interpretation

Bile Esculin Test- Principle, Procedure and Result Interpretation

Bile Esculin Test- Principle, Procedure and Result Interpretation Objectives of Bile Esculin Test This test is used for the presumptive identification of enterococci and organisms in the Streptococcus bovis group. The test differentiates enterococci and group D streptococci from non–group D viridans streptococci. Principle of Bile Esculin Test Gram-positive bacteria other than some streptococci and enterococci are inhibited by the bile salts …

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