Dental plaque is defined as the tenacious microbial deposit that forms on the hard tissue of the tooth surface. It comprises of living, dead and dying bacteria and their metabolic products as well as the components from the host saliva. Plaque formation also occur on restorations and other prosthetic appliances fixed in individuals who may […]
Hydrogen sulphide test: Hydrogen sulphide test is used to identify bacteria that produce the gas, hydrogen sulphide (H2S). Hydrogen sulphide (H2S) production test is used for the detection of hydrogen sulphide (H2S) gas produced by an organism. H2S is produced by bacteria during the anaerobic metabolism of sulphur containing amino acids (e.g. cysteine). This gas
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Biochemical Tests in Microbiology Lab
Methyl red test is used to identify pathogenic bacteria that produce acid from glucose phosphate. Some bacterial isolates ferment glucose through the mixed acid fermentation pathway to produce several acids including acetic acid, formic acid and lactic acid. Production of steady amounts of acids by these microorganisms will result in a pH level that is
Amylase (Starch hydrolysis) test is used to identify bacteria that hydrolyze starch (including amylopectin and amylose) with the help of the enzyme amylase. Amylase is an enzyme that hydrolyzes starch into maltose, glucose, and dextrin’s. Some bacterial isolates including Bacillus and Clostridium have the ability to produce α-amylase and other enzymes that degrade starch molecules
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Biochemical Tests in Microbiology Lab
Blood agar haemolysis is used to determine the haemolytic ability of some pathogenic microorganisms including Streptococcus pneumoniae, Staphylococcus aureus and Micrococcus species. Some pathogenic bacteria are capable of expressing some specific exotoxins known as haemolysin – which reacts as antibodies homologous to the surface antigens of red blood cells (erythrocytes). This phenomenon allows these organisms
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Biochemical Tests in Microbiology Lab
Satellitism test is a culture-based test which is used to identify Haemophilus influenzae in the laboratory. Haemophilus influenzae is a fastidious bacterium that requires both X factor (haemin) and V factor (NAD or NADP) for growth. Blood agar lacking any of these growth factors will not support most strains of H. influenzae. When grown in
Fungal reproduction is unique and distinct from those of other microbial cells such as bacteria. Generally, fungi exhibit two modes of reproduction which are sexual and asexual reproduction. In this section, the terms conidia and spores are synonymously used but with caution since conidia are generally used to describe asexual spores of fungi. Asexual reproduction
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Mycology
Key facts about zika virus infection Zika virus is a mosquito-borne flavivirus that was first identified in Uganda in 1947 in monkeys. It was later identified in humans in 1952 in Uganda and the United Republic of Tanzania. Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Asia and the Pacific. From
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Virology
Chikungunya is a mosquito-borne viral disease first described during an outbreak in southern Tanzania in 1952. It is an RNA virus that belongs to the alphavirus genus of the family Togaviridae. The name “chikungunya” derives from a word in the Kimakonde language, meaning “to become contorted”, and describes the stooped appearance of sufferers with joint pain (arthralgia).
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Virology
Baird–parker agar is a selective medium for the enumeration of Staphylococcus aureus in foods and this was first reported by Baird–Parker. Baird-Parker Agar was developed by Baird Parker in 1962. It is a selective medium for the detection and enumeration of coagulase-positive staphylococci from food samples. Baird-Parker agar is a type of agar used for
