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Microorganisms with Probiotic Properties

Probiotics are defined as live microorganisms, which when administered in adequate amounts, confer a health benefit on the host. Species of Lactobacillus and Bifidobacterium are most commonly used as probiotics. The yeast Saccharomyces boulardii and [...]

Probiotics, Prebiotics and Health Benefits

World Health Organization (WHO) defines “probiotics” as “live microorganisms that, when administered in adequate amounts, confer a perceived health benefit on the host”. These intentionally ingested microorganisms consist mainly of bacteria but also include yeasts. [...]

Cell Wall–Deficient Bacteria

Last updated on June 30th, 2021 Although most prokaryotes cannot survive in nature without their cell walls, some do so naturally. These include the mycoplasmas, a group of pathogenic bacteria that causes several infectious diseases [...]

Virus: Introduction and Structural Properties

Viruses are genetic elements that cannot replicate independently of a living host cell. Host cells provide energy, metabolic intermediates needed for replication and also synthesize viral proteins. As viruses need suitable living cells to multiply, [...]

Mutation and Types of Mutations

A mutation is a change in the nucleotide sequence of a gene. This gives rise to a new genetic trait or a changed genotype. A cell or an organism that shows the effect of a [...]

Superantigen (SAg): Examples and Roles

Last updated on May 30th, 2021 Superantigens are microbial peptides that can polyclonally activate a large fraction of T cells (up to 20%). They escape normal antigen processing by antigen presenting cells (APCs) and can […]

Cells of the Immune System

The immune system consists of many different organs, tissues, and cells scattered throughout the body but connected via blood vessels or lymphatic channels. These cells communicate with each other using protein signals (cytokines, complement, and […]

Gram Staining: Principle, Procedure, Results

Last updated on June 17th, 2021 Gram staining method, the most important procedure in Microbiology, was developed by Danish physician Hans Christian Gram in 1884. Gram staining is still the cornerstone of bacterial identification and taxonomic […]

API 20E Test System: Results and Interpretations

Last updated on June 21st, 2021 API (Analytical Profile Index) 20E is a biochemical panel from bioMerieux, Inc. for the identification and differentiation of members of the family Enterobacteriaceae. The plastic strip holds twenty mini-test chambers […]

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