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Selenite Broth
Selenite broth is used as a selective medium for the isolation of '' Salmonella'' species. Selenite broth was originated by Leifson, while observing good recovery of Salmonella spp. and reduced growth of fecal coliforms. Selenite broth is used as a selective enrichment for the cultivation of Salmonella spp. that may be present in small numbers and competing with intestinal flora. This medium must not be autoclaved. Once prepared, it is steamed at 100°C for 30 minutes. There should be a very slight red precipitate. To minimize the risk of teratogenicity to workers, sodium selenite Sodium selenite is the inorganic compound with the formula Na2SeO3. This salt is a colourless solid. The pentahydrate Na2SeO3(H2O)5 is the most common water-soluble selenium compound. Synthesis and fundamental reactions Sodium selenite usually i ... must be added separately to the medium. It has a pH of approximately 7.1. Selenite broth gives pale or colorless colonies. Selenite broth contains: R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmonella
''Salmonella'' is a genus of rod-shaped (bacillus) Gram-negative bacteria of the family Enterobacteriaceae. The two species of ''Salmonella'' are ''Salmonella enterica'' and ''Salmonella bongori''. ''S. enterica'' is the type species and is further divided into six subspecies that include over 2,600 serotypes. ''Salmonella'' was named after Daniel Elmer Salmon (1850–1914), an American veterinary surgeon. ''Salmonella'' species are non-spore-forming, predominantly motile enterobacteria with cell diameters between about 0.7 and 1.5 μm, lengths from 2 to 5 μm, and peritrichous flagella (all around the cell body, allowing them to move). They are chemotrophs, obtaining their energy from oxidation and reduction reactions, using organic sources. They are also facultative anaerobes, capable of generating ATP with oxygen ("aerobically") when it is available, or using other electron acceptors or fermentation ("anaerobically") when oxygen is not available. ''Salmonella'' spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Growth Medium
A growth medium or culture medium is a solid, liquid, or semi-solid designed to support the growth of a population of microorganisms or cells via the process of cell proliferation or small plants like the moss ''Physcomitrella patens''. Different types of media are used for growing different types of cells. The two major types of growth media are those used for cell culture, which use specific cell types derived from plants or animals, and those used for microbiological culture, which are used for growing microorganisms such as bacteria or fungi. The most common growth media for microorganisms are nutrient broths and agar plates; specialized media are sometimes required for microorganism and cell culture growth. Some organisms, termed fastidious organisms, require specialized environments due to complex nutritional requirements. Viruses, for example, are obligate intracellular parasites and require a growth medium containing living cells. Types The most common growth media ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autoclave
An autoclave is a machine used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure and/or temperature. Autoclaves are used before surgical procedures to perform sterilization and in the chemical industry to cure coatings and vulcanize rubber and for hydrothermal synthesis. Industrial autoclaves are used in industrial applications, especially in the manufacturing of composites. Many autoclaves are used to sterilize equipment and supplies by subjecting them to pressurized saturated steam at for around 30-60 minutes at a pressure of 15 psi (103 kPa or 1.02 atm) depending on the size of the load and the contents. The autoclave was invented by Charles Chamberland in 1879, although a precursor known as the steam digester was created by Denis Papin in 1679. The name comes from Greek ''auto-'', ultimately meaning self, and Latin ''clavis'' meaning key, thus a self-locking device. Uses Sterilization autoclav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teratogenicity
Teratology is the study of abnormalities of physiological development in organisms during their life span. It is a sub-discipline in medical genetics which focuses on the classification of congenital abnormalities in dysmorphology. The related term developmental toxicity includes all manifestations of abnormal development that are caused by environmental insult. These may include growth retardation, delayed mental development or other congenital disorders without any structural malformations. Teratogens are substances that may cause birth defects via a toxic effect on an embryo or fetus. Known teratogens include: retinol, thalidomide, mercury, alcohol, lead, polychlorinated biphenyls (PCBs), and 2,3,7,8-tetrachlorodibenzodioxin. Etymology The term was borrowed in 1842 from the French , where it was formed in 1830 from the Greek (word stem ), meaning "sign sent by the gods, portent, marvel, monster", and (''-ology''), used to designate a discourse, treaty, science, theory, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Selenite
Sodium selenite is the inorganic compound with the formula Na2SeO3. This salt is a colourless solid. The pentahydrate Na2SeO3(H2O)5 is the most common water-soluble selenium compound. Synthesis and fundamental reactions Sodium selenite usually is prepared by the reaction of selenium dioxide with sodium hydroxide: :SeO2 + 2 NaOH → Na2SeO3 + H2O The hydrate converts to the anhydrous salt upon heating to 40 °C. According to X-ray crystallography, both anhydrous Na2SeO3 and its pentahydrate feature pyramidal SeO32−. The Se-O distances range from 1.67 to 1.72 Å. Oxidation of this anion gives sodium selenate, Na2SeO4. Applications Together with the related barium and zinc selenites, sodium selenite is mainly used in the manufacture of colorless glass. The pink color imparted by these selenites cancels out the green color imparted by iron impurities. Because selenium is an essential element, sodium selenite is an ingredient in dietary supplements such as multi-v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptide
Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. A polypeptide is a longer, continuous, unbranched peptide chain. Hence, peptides fall under the broad chemical classes of biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. A polypeptide that contains more than approximately 50 amino acids is known as a protein. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, or to another protein or other macromolecule such as DNA or RNA, or to complex macromolecular assemblies. Amino acids that have been incorporated into peptides are termed residues. A water molecule is released during formation of each amide bond.. All peptides except cyclic pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mannitol
Mannitol is a type of sugar alcohol used as a sweetener and medication. It is used as a low calorie sweetener as it is poorly absorbed by the intestines. As a medication, it is used to decrease pressure in the eyes, as in glaucoma, and to lower increased intracranial pressure. Medically, it is given by injection or inhalation. Effects typically begin within 15 minutes and last up to 8 hours. Common side effects from medical use include electrolyte problems and dehydration. Other serious side effects may include worsening heart failure and kidney problems. It is unclear if use is safe in pregnancy. Mannitol is in the osmotic diuretic family of medications and works by pulling fluid from the brain and eyes. The discovery of mannitol is attributed to Joseph Louis Proust in 1806. It is on the World Health Organization's List of Essential Medicines. It was originally made from the flowering ash and called manna due to its supposed resemblance to the Biblical food. Mannitol is on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Selenite
Sodium selenite is the inorganic compound with the formula Na2SeO3. This salt is a colourless solid. The pentahydrate Na2SeO3(H2O)5 is the most common water-soluble selenium compound. Synthesis and fundamental reactions Sodium selenite usually is prepared by the reaction of selenium dioxide with sodium hydroxide: :SeO2 + 2 NaOH → Na2SeO3 + H2O The hydrate converts to the anhydrous salt upon heating to 40 °C. According to X-ray crystallography, both anhydrous Na2SeO3 and its pentahydrate feature pyramidal SeO32−. The Se-O distances range from 1.67 to 1.72 Å. Oxidation of this anion gives sodium selenate, Na2SeO4. Applications Together with the related barium and zinc selenites, sodium selenite is mainly used in the manufacture of colorless glass. The pink color imparted by these selenites cancels out the green color imparted by iron impurities. Because selenium is an essential element, sodium selenite is an ingredient in dietary supplements such as multi-v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbiological Media
Microbiology () is the branches of science, scientific study of microorganisms, those being unicellular organism, unicellular (single cell), multicellular organism, multicellular (cell colony), or non-cellular life, acellular (lacking cells). Microbiology encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology, and parasitology. eukaryote, Eukaryotic microorganisms possess membrane-bound organelles and include fungi and protists, whereas prokaryote, prokaryotic organisms—all of which are microorganisms—are conventionally classified as lacking membrane-bound organelles and include Bacteria and Archaea. Microbiologists traditionally relied on culture, staining, and microscopy. However, less than 1% of the microorganisms present in common environments can be cultured in isolation using current means. Microbiologists often rely on molecular biology tools such as DNA sequence based identification, for example the 16S ribosomal RNA, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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