Structure of Major Histocompatibility Complex (MHC)

Structure of Major Histocompatibility Complex (MHC)

Class I and Class II MHC antigens have a somewhat different structure. MHC Class I molecules MHC Class I molecules in both human and mouse consist of two polypeptide chains that dramatically differ in size. The larger (α) chain has a molecular weight of 44 kDa in humans and 47 kDa in the mouse, and … Read more Structure of Major Histocompatibility Complex (MHC)

Normal Human Microbiota

Normal Human Microbiota

Through normal everyday activities, the human body is exposed to microorganisms in the environment. Hundreds of species and countless individual microbial cells, collectively called the normal microflora, grow on or in the human body. This is the human microbiome, the sum total of all microorganisms that live on or in the human body. The normal … Read more Normal Human Microbiota

Innate Immune System- An Introduction

Innate Immune System- An Introduction

Introduction The innate immune system provides the first line of host defense against microbes, before adaptive immune responses have had sufficient time to develop. The mechanisms of innate immunity exist before exposure to microbes. The cellular components of the innate immune system include epithelial barriers and leukocytes (neutrophils, macrophages, NK cells, lymphocytes with invariant antigen … Read more Innate Immune System- An Introduction

Biochemical Test of Bacillus cereus

Biochemical Test of Bacillus cereus

Biochemical Test of Bacillus cereus ­Basic Characteristics Properties (Bacillus cereus) Catalase Positive (+ve) Citrate Positive (+ve) Gelatin Hydrolysis Negative (-ve) Gram Staining Positive (+ve) Growth in KCN Positive (+ve) Hemolysis Positive (+ve) Indole Negative (-ve) Motility Positive (+ve) MR (Methyl Red) Negative (-ve) Nitrate Reduction Variable Oxidase Negative (-ve) Pigment Negative (-ve) Shape Rods Spore … Read more Biochemical Test of Bacillus cereus

How viruses cause disease?

How viruses cause disease

Viruses gain access to the host through skin and mucous membranes, and via the respiratory, gastrointestinal, and genital tracts. Their virulence or lack of it may be determined by very small mutations in the genome. Viral infection of cells may result in lysis, fusion and syncytium formation, the appearance of inclusion bodies, or, in some … Read more How viruses cause disease?

Biochemical Test of Serratia marcescens

Biochemical Test of Serratia marcescens

Biochemical Test of Serratia marcescens ­Basic Characteristics Properties (Serratia marcescens) Capsule Negative (-ve) Catalase Positive (+ve) Citrate Positive (+ve) Flagella Positive (+ve) Gas Variable Gelatin Hydrolysis Positive (+ve) Gram Staining Negative (-ve) H2S Negative (-ve) Indole Negative (-ve) Motility Positive (+ve) MR (Methyl Red) Negative (-ve) Nitrate Reduction Positive (+ve) OF (Oxidative-Fermentative) Facultative Anaerobes Oxidase … Read more Biochemical Test of Serratia marcescens

Viruses- Structure, Replication and Diagnosis

Viruses- Structure, Replication and Diagnosis

Structure of Virus LIPID ENVELOPE Usually formed from a lipid bilayer taken from their host, into which the virus inserts its own glycoproteins (enveloped virus). Not all viruses have envelopes (naked virus). Viruses without envelopes are less prone to damage by external factors, such as pH, than those with envelopes. The lipid envelope also determines … Read more Viruses- Structure, Replication and Diagnosis

Vaccines- Introduction and Types with Examples

Vaccines- Introduction and Types

A vaccine is a medical preparation given to provide immunity from a disease. Vaccines use a variety of different substances ranging from dead microorganisms to genetically engineered antigens to defend the body against potentially harmful microorganisms. Effective vaccines change the immune system by promoting the development of antibodies that can quickly and effectively attack disease-causing … Read more Vaccines- Introduction and Types with Examples

Differences between antigen and antibody (Antigen vs Antibody)

Differences between antigen and antibody

Differences between antigen and antibody Antibodies are produced by the immune system in response to antigens (material perceived as foreign). The antibody response to a particular antigen is highly specific and often involves a physical association between the two molecules. This association is governed by biochemical and molecular forces. The reaction between antigens (Ags) and antibodies … Read more Differences between antigen and antibody (Antigen vs Antibody)

Biochemical Test of Clostridium difficile

Biochemical Test of Clostridium difficile

Biochemical Test of Clostridium difficile ­Basic Characteristics Properties (Clostridium difficile) Capsule Capsulated Catalase Negative (-ve) Flagella Flagellated Gelatin Hydrolysis Positive (+ve) Gram Staining Positive (+ve) H2S Positive (+ve) Hemolysis Negative (-ve) Indole Negative (-ve) Motility Motile Nitrate Reduction Negative (-ve) OF (Oxidative-Fermentative) Anaerobic Oxidase Negative (-ve) Shape Rods Spore Positive (+ve) Urease Negative (-ve) VP … Read more Biochemical Test of Clostridium difficile