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Citrobacter Freundii
''Citrobacter freundii'' is a species of facultative anaerobic Gram-negative bacteria of the family Enterobacteriaceae which currently consists of 13 recognized species. These bacteria have a rod shape with a typical length of 1–5 μm. Most ''C. freundii'' cells have several flagella used for locomotion, although some non-motile taxa do not. ''C. freundii'' is a soil-dwelling microorganism, but can also be found in water, sewage, food, and the intestinal tracts of animals and humans. The genus Citrobacter was discovered in 1932 by Werkman and Gillen. Cultures of ''C. freundii'' were isolated and identified in the same year from soil extracts. Cell morphology and features Exopolysaccharides from ''C. freundii'' target the hydroxyl radical, demonstrating antioxidant activity. These antioxidant properties are related to many different physical and chemical properties. ''C. freundii'' can also have a positive impact when it comes to the treatment of some cancers; specifically, it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-negative Bacteria
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane. Gram-negative bacteria are found in virtually all environments on Earth that support life. The gram-negative bacteria include the model organism ''Escherichia coli'', as well as many pathogenic bacteria, such as ''Pseudomonas aeruginosa'', '' Chlamydia trachomatis'', and ''Yersinia pestis''. They are a significant medical challenge as their outer membrane protects them from many antibiotics (including penicillin), detergents that would normally damage the inner cell membrane, and lysozyme, an antimicrobial enzyme produced by animals that forms part of the innate immune system. Additionally, the outer leaflet of this membrane comprises a complex lipopol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HeLa
HeLa (; also Hela or hela) is an immortalized cell line used in scientific research. It is the oldest and most commonly used human cell line. The line is derived from cervical cancer cells taken on February 8, 1951, named after Henrietta Lacks, a 31-year-old African-American mother of five, who died of cancer on October 4, 1951. The cell line was found to be remarkably durable and prolific, which allows it to be used extensively in scientific study. The cells from Lacks's cancerous cervical tumor were taken without her knowledge or consent, which was common practice in the United States at the time. Cell biologist George Otto Gey found that they could be kept alive, and developed a cell line. Previously, cells cultured from other human cells would only survive for a few days. Cells from Lacks's tumor behaved differently. History Origin In 1951, a patient named Henrietta Lacks was admitted to the Johns Hopkins Hospital with symptoms of irregular vaginal bleeding, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biofilm
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular polymeric substances (EPSs). The cells within the biofilm produce the EPS components, which are typically a polymeric conglomeration of extracellular polysaccharides, proteins, lipids and DNA. Because they have three-dimensional structure and represent a community lifestyle for microorganisms, they have been metaphorically described as "cities for microbes". Biofilms may form on living or non-living surfaces and can be prevalent in natural, industrial, and hospital settings. They may constitute a microbiome or be a portion of it. The microbial cells growing in a biofilm are physiologically distinct from planktonic cells of the same organism, which, by contrast, are single cells that may float or swim in a liquid medium. Biofilms c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycerol
Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known as glycerides. Because it has antimicrobial and antiviral properties, it is widely used in wound and burn treatments approved by the U.S. Food and Drug Administration. Conversely, it is also used as a bacterial culture medium. It can be used as an effective marker to measure liver disease. It is also widely used as a sweetener in the food industry and as a humectant in pharmaceutical formulations. Because of its three hydroxyl groups, glycerol is miscible with water and is hygroscopic in nature. Structure Although achiral, glycerol is prochiral with respect to reactions of one of the two primary alcohols. Thus, in substituted derivatives, the stereospecific numbering labels the molecule with a "sn-" prefix before the stem name of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propanediol
Propanediol may refer to any of four isomeric organic chemical compounds: Non-geminal diols (glycols) * 1,2-Propanediol, a.k.a. propylene glycol, a vicinal diol * 1,3-Propanediol, a.k.a. trimethylene glycol Geminal diols * 1,1-Propanediol * 2,2-Propanediol {{Chemistry index ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Red
Methyl red (2-(''N'',''N''-dimethyl-4-aminophenyl) azobenzenecarboxylic acid), also called C.I. Acid Red 2, is an indicator dye that turns red in acidic solutions. It is an azo dye, and is a dark red crystalline powder. Methyl red is a pH indicator; it is red in pH under 4.4, yellow in pH over 6.2, and orange in between, with a p''K''a of 5.1. Murexide and methyl red are investigated as promising enhancers of sonochemical destruction of chlorinated hydrocarbon pollutants. Methyl red is classed by the IARC in group 3 - unclassified as to carcinogenic potential in humans. Preparation As an azo dye, methyl red may be prepared by diazotization of anthranilic acid, followed by reaction with dimethylaniline: : Properties Methyl red displays pH dependent photochromism, with protonation causing it to adopt a hydrazone/quinone structure. : Methyl Red has a special use in histopathology for showing acidic nature of tissue and presence of organisms with acidic natured cell walls. Met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voges–Proskauer Test
Voges–Proskauer or VP is a test used to detect acetoin in a bacterial broth culture. The test is performed by adding alpha-naphthol and potassium hydroxide to the Voges-Proskauer broth, which is a glucose-phosphate broth that has been inoculated with bacteria. A cherry red color indicates a positive result, while a yellow-brown color indicates a negative result. The test depends on the digestion of glucose to acetylmethylcarbinol. In the presence of oxygen and strong base, the acetylmethylcarbinol is oxidized to diacetyl, which then reacts with guanidine compounds commonly found in the peptone medium of the broth. Alpha-naphthol acts as a color enhancer, but the color change to red can occur without it. Procedure: First, add the alpha-naphthol; then, add the potassium hydroxide. A reversal in the order of the reagents being added may result in a weak-positive or false-negative reaction. VP is one of the four tests of the IMViC series, which tests for evidence of an enter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biodegradation
Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegradation occurs under a specific set of circumstances. The process of biodegradation is threefold: first an object undergoes biodeterioration, which is the mechanical weakening of its structure; then follows biofragmentation, which is the breakdown of materials by microorganisms; and finally assimilation, which is the incorporation of the old material into new cells. In practice, almost all chemical compounds and materials are subject to biodegradation, the key element being time. Things like vegetables may degrade within days, while glass and some plastics take many millennia to decompose. A standard for biodegradability used by the European Union is that greater than 90% of the original material must be converted into , water and minerals b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tannic Acid
Tannic acid is a specific form of tannin, a type of polyphenol. Its weak acidity ( pKa around 6) is due to the numerous phenol groups in the structure. The chemical formula for commercial tannic acid is often given as C76H52O46, which corresponds with decagalloyl glucose, but in fact it is a mixture of polygalloyl glucoses or polygalloyl quinic acid esters with the number of galloyl moieties per molecule ranging from 2 up to 12 depending on the plant source used to extract the tannic acid. Commercial tannic acid is usually extracted from any of the following plant parts: Tara pods (''Caesalpinia spinosa''), gallnuts from '' Rhus semialata'' or ''Quercus infectoria'' or Sicilian sumac leaves ('' Rhus coriaria''). According to the definitions provided in external references such as international pharmacopoeia, Food Chemicals Codex and FAO-WHO tannic acid monograph only tannins obtained from the above-mentioned plants can be considered as tannic acid. Sometimes extracts from che ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanneries
Tanning may refer to: *Tanning (leather), treating animal skins to produce leather *Sun tanning, using the sun to darken pale skin **Indoor tanning, the use of artificial light in place of the sun **Sunless tanning, application of a stain or dye to the skin (active ingredient in tanning lotion products is dihydroxyacetone (DHA)). * Physical punishment, metaphorically, such as a severe spanking which leaves clear marks See also *Skin whitening *Tan (color) *Tan (other) Tan or TAN may refer to: Businesses and organisations * Black and Tans, a nickname for British special constables during the Irish War of Independence. By extension "Tans" can now also colloquially refer to English or British people in general, ... * Tannin (other) {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fenvalerate
Fenvalerate is a synthetic pyrethroid insecticide. It is a mixture of four optical isomers which have different insecticidal activities. The 2-S ''alpha'' (or SS) configuration, known as esfenvalerate, is the most insecticidally active isomer. Fenvalerate consists of about 23% of this isomer. Fenvalerate is an insecticide of moderate mammalian Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fu ... toxicity. In laboratory animals, central nervous system toxicity is observed following acute or short-term exposure. Fenvalerate has applications against a wide range of pests including some of the more destructive such as the '' Helicoverpa assulta''. Residue levels are minimized by low application rates. Fenvalerate is most toxic to bees and fish. It is found in some emulsifiable concentra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrogen Cycle
The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification. The majority of Earth's atmosphere (78%) is atmospheric nitrogen, making it the largest source of nitrogen. However, atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in many types of ecosystems. The nitrogen cycle is of particular interest to ecologists because nitrogen availability can affect the rate of key ecosystem processes, including primary production and decomposition. Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers, and release of nitrogen in wastewater have dramatically altered the global n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
