Citrate test is used to identify Enterobacteriaceae that utilize citrate or citric acid as their sole carbon and energy source. Simmon’s citrate agar or citrate tablet is used in performing this test but only the Simmon’s citrate agar method is expanded in this book. The Simmons citrate agar tests the ability of organisms to utilize […]
Urease test is used to detect and differentiate Enterobacteriaceae that produce urease enzymes from those that do not. The urease test is used to determine the ability of an organism to split urea, through the production of the enzyme urease. Urease is an exoenzyme that hydrolyzes urea to produce ammonia and carbondioxide. Urease positive enterobacteria
Indole test (Tryptophan hydrolysis) is used to identify Enterobacteria that breakdown tryptophan (an amino acid) to produce indole. The indole test is a biochemical test performed on bacterial species to determine the ability of the organism to convert tryptophan into the indole. Tryptophan hydrolysis is catalyzed by the enzyme tryptophanase to produce indole and pyruvic
Oxidase test is used to identify microorganisms that produce the enzyme, cytochrome-c oxidase. Cytochrome-c oxidase, a respiratory enzyme is an important enzyme of the electron transport chain (ETC), where it catalyzes the transport of electrons from a donor compound (e.g. NADH) to oxygen, the final electron acceptor. If cytochrome-c oxidase is present, it will oxidize
Catalase test is used to identify microorganisms that produce catalase enzyme. It is used to differentiate catalase-producing organisms (e.g. Staphylococcus species) from non-catalase producing bacteria (e.g. Streptococcus species). Catalase enzyme breakdown hydrogen peroxide (H2O2) to water and oxygen; and this leads to the release or production of bubbles – which indicates a positive test result
Coagulase test is used to distinguish pathogenic Staphylococcus aureus (which is coagulase positive) from nonpathogenic strains of S. aureus (which is coagulase negative). This test is used to differentiate Staphylococcus aureus (positive) from Coagulase Negative Staphylococcus (CONS). Coagulase is an enzyme produced by S. aureus that converts (soluble) fibrinogen in plasma to (insoluble) fibrin. Staphylococcus
Biochemical tests are series of experiments that can be used to differentiate bacteria based on their metabolic activity or ability to utilize a given substrate such as glucose. These tests are generally useful in characterizing bacteria in the Microbiology Laboratory, and they take advantage of the organism’s physiological, osmotic, and nutritional requirements. The identification of
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Biochemical Tests in Microbiology Lab
The cell as we know is the basic unit of life. Microorganisms are cellular entities, and thus could be likened to a cell. They can either exist as unicellular organisms or organisms with multiple cells (i.e. as multicellular organisms). Microbial cells are ubiquitous in the natural environment, and are found in the soil, water, in
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Microbial Physiology & Metabolism
As one of the world’s most research-intensive industry, biotechnology corporations are high-profit making enterprises that seek to increase their economic base while obtaining high returns from their investments. Research and development (R&D) spending in the biotechnology industries of most nations including the United States of America runs into billions of dollars. Recombinant human insulin for
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Biotechnology
After exposure to an infectious agent, the body becomes contaminated by the agent, and the pathogenic microorganism eventually develops disease or infection in the susceptible human or animal host following a defined pattern (Figure 1). It is the duty of clinical microbiologists to isolate and characterize the infecting pathogenic microorganism(s), and differentiate same from normal
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Bacteriology