Sagar Aryal, PhD 
(Type A and proteolytic strains of types B and F) Basic Characteristics Properties (Clostridium botulinum) Ammonia Production Positive (+ve) 20% Bile Negative (-ve) Capsule Negative (-ve) Catalase Negative (-ve) Flagella … Read more
The Davson–Danielli model (or paucimolecular model) was a model of the plasma membrane of a cell, proposed in 1935 by Hugh Davson and James Danielli. The model describes a phospholipid bilayer that lies between two layers of globular proteins and it … Read more
Secretory Vesicles Definition Vesicles are small, membrane-enclosed sacs that store and transport substances to and from one cell to another and from one part of a cell to another. The … Read more
The plasma membrane, also known as the cell surface membrane or plasmalemma, defines the boundary of the cell. They are a special type of membranes which are lipid structures that … Read more
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 … Read more
Laboratory diagnosis of Streptococcus pneumoniae Specimen: Sputum, blood, endotracheal aspirate, bronchoalveolar lavage, cerebrospinal fluid (CSF), pleural fluid, joint fluid, abscess fluid, bones, and other biopsy material. Microscopy Gram staining of … Read more
Virulence factors of Streptococcus pneumoniae Polysaccharide capsule The capsule is antiphagocytic, inhibiting complement deposition and phagocytosis. 2. Cell wall associated polymers and proteins Teichoic acid – binds to epithelial cells … Read more
A microbe that is capable of causing disease is referred to as a pathogen. Pathogenicity is the ability of a microorganism to cause disease in another organism, namely the host. Pathogens vary in … Read more
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 … Read more
Both light microscopes and electron microscopes use radiation (light or electron beams) to form larger and more detailed images of objects which cannot be seen clearly through an unaided eye. Light Microscope … Read more
