Esculin Hydrolysis Test- Principle, Procedure, Results, Uses

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Esculin Hydrolysis Test- Principle, Procedure and Result Interpretation

What is the Esculin Hydrolysis Test? Esculin hydrolysis is a useful test in the differentiation of both gram-positive and gram-negative bacteria covering a broad spectrum of aerobes, facultative anaerobes, and anaerobes. Esculin hydrolysis is utilized as a taxonomic tool in the identification of a wide variety of microorganisms, including the family Enterobacteriaceae, genera Streptococcus and Listeria, non-fermentative gram-negative bacilli, and anaerobes. Esculin hydrolysis is a differential test that differentiates bacteria on the basis of their ability to hydrolyze esculin. This … Read more

Lipase Test- Objectives, Principle, Procedures, Results, Uses

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Result Interpretation of Lipase Test

Objectives of Lipase Test The objective is to identify bacteria capable of producing the exoenzyme lipase. The Lipase Test is used to detect and enumerate lipolytic bacteria, especially in high-fat dairy products. A variety of other lipid substrates, including corn oil, olive oil, and soybean oil, are used to detect differential characteristics among members of Enterobacteriaceae, Clostridium, Staphylococcus, and Neisseria. Several fungal species also demonstrate lipolytic ability. Principle of Lipase Test Fats are formed by ester linkage between three molecules of fatty acids … Read more

Asexual vs Sexual Reproduction- Definition, 16 Differences, Examples

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Differences Between Asexual and Sexual Reproduction

Asexual Reproduction Definition Asexual reproduction is a mode of reproduction that occurs without the fusion of gametes and doesn’t involve the exchange of genetic information, resulting in offsprings identical to their parents. Asexual reproduction in living beings is characterized by the absence of male and female gametes and the lack of change in the number of chromosomes in the offspring. As no specific gametes are formed during asexual reproduction, the somatic cells act as gametes. The body of the organism … Read more

Hypersensitivity Type I, II, III and IV- Summary in table form

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Hypersensitivity Type I, II, III and IV in one table

Image Source: Pinterest. Here is the comparison table: Alternative Name Type I Type II Type III Type IV Allergic hypersensitivity Cytotoxic hypersensitivity Immune complex hypersensitivity Cell-mediated hypersensitivity/ Delayed type of hypersensitivity Principle Type I Type II Type III Type IV Antibody-mediated degranulation of granulocytes leading to the destruction of cells. Antibody-mediated destruction of healthy cells. Antigen-antibody complex-mediated destruction of cells. T lymphocytes mediated the destruction of cells. Primary Mediator Type I Type II Type III Type IV IgE IgG/IgM IgG/IgM … Read more

DNase Test- Definition, Principle, Procedure, Result, Uses

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DNase Test Agar- Principle, Procedure and Result Interpretation

Deoxyribonuclease (DNase) Test Definition Deoxyribonuclease (DNase) Test is a biochemical test performed to differentiate organisms on the basis of their ability to produce the DNase enzyme. Deoxyribonucleic acid (DNA) is a large molecular-sized polymer composed of multiple nucleotides monomer that is large in size and thus, cannot enter the bacterial cell membrane. Microorganisms produce the deoxyribonuclease enzyme to breakdown the DNA into smaller monomers which can then be taken into the cell easily. The nucleotides are used to make nucleic … Read more

Prokaryotes vs Eukaryotes- Definition, 47 Differences, Examples

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Differences between Prokaryotes and Eukaryotes

Differences between Prokaryotes and Eukaryotes Here are some of the differences: S.N. Character Prokaryotes Eukaryotes 1. Term Origin Greek for “primitive nucleus” Greek for “true nucleus” 2. Definition Organisms made up of cell(s) that lack a cell nucleus or any membrane-encased organelles. Organisms made up of cells that possess a membrane-bound nucleus as well as membrane-bound organelles. 3. Major groups Bacteria, Archae, and Bluegreen algae Algae, fungi, protozoa, plants, animals 4. Origin Around 3.5 billion years ago. Around 2 billion years … Read more

Serum vs Plasma- Definition and 17 Major Differences

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Differences between Serum and Plasma

Differences between Serum and Plasma Here are the major differences: S.N. Characteristics Serum Plasma 1. Definition The clear yellow fluid separated when blood is allowed to clot freely. Yellowish and slight alkaline fluid, in which blood cells float. 2. Clotting factors It is the watery fluid from blood without the clotting factors. It is the blood fluid that contains blood-clotting agents. 3. Composition The serum contains proteins, electrolytes, antibodies, antigens, and hormones. It contains all suspended blood cells with proteins, … Read more

Optochin Susceptibility Test- Principle, Procedure and Results

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Optochin Susceptibility Test- Principle, Procedure and Results

Objectives of Optochin Susceptibility Test To determine the effect of Optochin (ethyl hydrocupreine hydrochloride) on an organism. To differentiate between alpha-hemolytic Streptococcus pneumoniae from other alpha-hemolytic viridans Streptococci. Principle of Optochin Susceptibility Test Optochin (ethylhydrocupreine hydrochloride) is a chemical and is completely soluble in water. Optochin is an antibiotic that interferes with the ATPase and production of adenosine triphosphate (ATP) in microorganisms. Optochin is used in the presumptive identification of alpha-hemolytic Streptococcus pneumoniae. The chemical tests the fragility of the bacterial cell membrane and causes … Read more

Novobiocin Susceptibility Test- Principle, Procedure, Results, Uses

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Result Interpretation of Novobiocin Susceptibility Test

Objectives of Novobiocin Susceptibility Test To determine the susceptibility pattern of a bacterium to novobiocin. To distinguish or differentiate Staphylococcus saprophyticus from other coagulase-negative staphylococci. Principle of Novobiocin Susceptibility Test Novobiocin is an antibiotic interfering with the unpackaging and repackaging of DNA during DNA replication and the bacterial cell cycle. Novobiocin binds to DNA gyrase and blocks adenosine triphosphatase (ATPase) activity.  Laboratory identification of S. saprophyticus is made on the basis of the absence of hemolysis, coagulase, and resistance to novobiocin. Staphylococcus saprophyticus, Gram-positive coagulase-negative Staphylococci, is a … Read more

PYR Test- Objectives, Principle, Procedure, Result, Limitations

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Result Interpretation of PYR Test

Objectives of Pyrrolidonyl Arylamidase (PYR) Test To determine the ability of organism to produce L-pyrrolidonyl arylamidase enzyme. It aids in the presumptive identification of group A streptococci (Streptococcus pyogenes) and Enterococci by the presence of the enzyme L-pyrrolidonyl arylamidase. Principle of Pyrrolidonyl Arylamidase (PYR) Test Pyrrolidonyl Arylamidase (PYR) test is a rapid test that is used for the presumptive identification of group A beta-hemolytic Streptococci and Enterococci based on the activity of the enzyme pyrolidonyl arylamidase. Pyrrolidonyl arylamidase (PYR), also known as … Read more