Ames Test – Introduction, Principle, Procedure, Uses and Result Interpretation

Ames Test Procedure

Ames test it is a biological assay to assess the mutagenic potential of chemical compounds. It utilizes bacteria to test whether a given chemical can cause mutations in the DNA of the test organism. The test was developed by Bruce N. Ames in 1970s to determine if a chemical at hand is a mutagen. Objective To determine …

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Antibiotics: Comprehensive Guide

Guide to Antibiotics

Antibiotics (Greek anti, “against”; bios, “life”) are chemical compounds used to kill or inhibit the growth of infectious organisms. An antibiotic was originally defined in the 1940s as a substance produced by one microorganism which, in low concentrations, inhibited the growth of other microorganisms. Antibiotics are naturally occurring substances produced by a fungus or bacteria. …

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Difference between O Antigen and H Antigen

Difference between O Antigen and H Antigen

The antigen used to define serological test of Salmonella include Somatic O antigen, Flagellar H antigen and Vi antigen (Capsular antigen). Some of the differences between O Antigen and H Antigen are as follows: S.N. Characteristics O Antigen H Antigen 1. Types Somatic Antigen Flagellar antigen 2. Composition Polysaccharide Proteinaceous 3. Antibody formation Rapid and …

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List of culture media used in microbiology with their uses

Media Microbiology

Media Uses ·   Alkaline Peptone Water Enrichment media for Vibrio cholerae ·   Alkaline Salt Transport Medium ·   Taurocholate Peptone Transport Medium Transport media for diarrheal diseases suspected of being caused by V. cholerae ·   Anaerobic Media Liquid media by addition of ·     Glucose (0.5 % to 1 %) ·     Ascorbic Acid (0.1 %) ·     Cysteine …

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Differences Between Bacteria and Viruses

Differences Between Bacteria and Viruses

Although bacteria and viruses both are very small to be seen without a microscope, there are many differences between Bacteria and Viruses. Some of the Differences Between Bacteria and Viruses are as follows: S.N. Characteristics Bacteria Viruses 1 Size Larger (1000 nm) Smaller (20-400 nm) 2 Cell Wall Peptidoglycan or Lipopolysaccharide No cell wall. Protein …

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Differences Between Diarrhea And Dysentery

Differences Between Diarrhea And Dysentery

Diarrhea is a condition that involves the frequent passing of loose or watery stools while Dysentery is an intestinal inflammation, especially in the colon, that can lead to severe diarrhea with mucus or blood in the feces. The major differences between Diarrhea and Dysentery are as follows: S.N. Diarrhea Dysentery 1. Diarrhea is presented as watery …

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Differences Between Exotoxins and Endotoxins

Differences Between Exotoxins and Endotoxins

Many bacteria produce toxins, enzymes and pigments. Toxins and enzymes play important role in pathogenecity. Toxins are of two types: Exotoxins are usually heat labile proteins secreted by certain species of bacteria which diffuse into the surrounding medium. Endotoxins are heat stable lipopolysaccharide-protein complexes which form structural components of cell wall of Gram Negative Bacteria …

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Differences Between Cilia and Flagella

Differences Between Cilia and Flagella

Flagella are the complex filamentous cytoplasmic structure protruding through cell wall. These are unbranched, long, thread like structures, mostly composed of the protein flagellin, intricately embedded in the cell envelope. Cilia are slender, microscopic, hair-like structures or organelles that extend from the surface of nearly all mammalian cells (multiple or single). S.N. Characteristics Cilia Flagella …

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Differences between Gram Positive and Gram Negative Bacteria

Differences between Gram Positive and Gram Negative Bacteria

S.N. Characteristics Gram Positive Gram Negative 1 Gram Reaction Retain crystal violet dye and stain blue or purple Can be decolorized to accept counterstain (safranin) and stain pink or red 2 Cell Wall Cell Wall is 20-30 nm thick. Cell Wall is 8-12 nm thick. 3 Cell Wall The wall is Smooth. The wall is …

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Different Size, Shape and Arrangement of Bacterial Cells

Different Size, Shape and Arrangement of Bacterial Cells

Bacteria are prokaryotic, unicellular microorganisms, which lack chlorophyll pigments. The cell structure is simpler than that of other organisms as there is no nucleus or membrane bound organelles. Due to the presence of a rigid cell wall, bacteria maintain a definite shape, though they vary as shape, size and structure. When viewed under light microscope, …

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Haemolysis of Streptococci and its types with examples

Haemolysis of Streptococci and its types with examples

Hemolysis is the breakdown of red blood cells (RBC). A substance that causes hemolysis is a hemolysin. Brown (1919) introduced three terms alpha, beta and gamma to indicate three types of streptococci based on haemolytic reactions observed on blood agar plates. Beta-hemolytic Streptococci Beta-hemolysis (β-hemolysis) is associated with complete lysis of red cells surrounding the colony. Beta …

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How to protect yourself from infectious diseases like diarrhoea, swine flu, etc. after an earthquake

How to protect yourself from infectious diseases like diarrhoea, swine flu, etc. after an earthquake

The eventual death toll from the massive earthquake that struck Nepal on April 25 will be unbearable. The death toll from Saturday’s deadly 7.9 magnitude quake and a series of aftershocks that struck various parts of Nepal has reached 4347 leaving 8154 injured as of Tuesday morning. The overwhelming majority of deaths immediately after a natural disaster …

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Top 50 Microbiology Colleges and Universities in the World

Top 50 Microbiology Colleges and Universities in the World

Microbiology is the study of microorganisms like bacteria, virus, fungi, protozoans which is seen only under the microscope and which have many economic importance. These are the world top 50 Microbiology Colleges and Universities on the basis of: Global research reputation, Regional research reputation, Publications, Normalized citation impact, Total citations, Number of publications that are …

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Differences between Light Microscope and Electron Microscope

Light Microscope and Electron Microscope

Differences between Light Microscope and Electron Microscope Light Microscope Electron Microscope Illuminating source is the Light. Illuminating source is the beam of electrons. Specimen preparation takes usually few minutes to hours. Specimen preparation takes usually takes few days. Live or Dead specimen may be seen. Only Dead or Dried specimens are seen. Condenser, Objective and eye …

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