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Agar
Agar ( or ), or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from ogonori ('' Gracilaria'') and "tengusa" ('' Gelidiaceae''). As found in nature, agar is a mixture of two components, the linear polysaccharide agarose and a heterogeneous mixture of smaller molecules called agaropectin. It forms the supporting structure in the cell walls of certain species of algae and is released on boiling. These algae are known as agarophytes, belonging to the Rhodophyta (red algae) phylum. The processing of food-grade agar removes the agaropectin, and the commercial product is essentially pure agarose. Agar has been used as an ingredient in desserts throughout Asia and also as a solid substrate to contain culture media for microbiological work. Agar can be used as a laxative; an appetite suppressant; a vegan substitute for gelatin; a thickener for soups; in fruit preserves, ice cream, and ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agarose
Agarose is a heteropolysaccharide, generally extracted from certain red seaweed. It is a linear polymer made up of the repeating unit of agarobiose, which is a disaccharide made up of D-galactose and 3,6-anhydro-L-galactopyranose. Agarose is one of the two principal components of agar, and is purified from agar by removing agar's other component, agaropectin. Agarose is frequently used in molecular biology for the separation of large molecules, especially DNA, by electrophoresis. Slabs of agarose gels (usually 0.7 - 2%) for electrophoresis are readily prepared by pouring the warm, liquid solution into a mold. A wide range of different agaroses of varying molecular weights and properties are commercially available for this purpose. Agarose may also be formed into beads and used in a number of chromatographic methods for protein purification. Structure Agarose is a linear polymer with a molecular weight of about 120,000, consisting of alternating D- galactose and 3,6-an ... [...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 me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agaropectin
Agaropectin is one of the two main components of agar and mainly consists of D-glucuronic acid and pyruvic acid. Structure Agaropectin is a sulphated galactan mixture which composes agar by 30% composition. It is the component of agar that is not agarose and is composed of varying percentages of ester sulfates, D-glucuronic acid and small amounts of pyruvic acid. Pyruvic acid is possibly attached in an acetal form to the D-galactose residues of the agarobiose skeleton. The sulfate content of the agar depends on the source of the raw material from which it is derived. Acetylation of agaropectin yields the chloroform-insoluble agaropectin acetate, as opposed to agarose acetate. This process can be used to separate the two polysaccharides via fractionation Fractionation is a separation process in which a certain quantity of a mixture (of gases, solids, liquids, enzymes, or isotopes, or a suspension) is divided during a phase transition, into a number of smaller quantities ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walther Hesse
Walther Hesse (27 December 1846 – 19 July 1911) is best known for his work in microbiology, specifically his work with his wife Fanny Hesse in developing agar as a medium for culturing microorganisms. Biography He was born in Bischofswerda, Lusatia, as one of 12 children in the family of a medical practitioner. Hesse attended the Kreuzschule in Dresden and studied medicine at the University of Leipzig with Ernst Leberecht Wagner from 1866 till 1870, when he received his doctorate in pathology. Afterwards he participated in the Franco-Prussian War, and therein in the Battle of Gravelotte. As a ship's physician on the New York Line 1872/73 he examined seasickness – his works were classified by Prof. Gavingel of Le Havre as the first scientific study on this topic at all. In New York City, Hesse met his later wife Angelina Fanny Eilshemius. The Eilshemius family were immigrants of Dutch-German origin – Angelina's brother Louis Eilshemius is known as an important painter, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Robert Koch
Heinrich Hermann Robert Koch ( , ; 11 December 1843 – 27 May 1910) was a German physician and microbiologist. As the discoverer of the specific causative agents of deadly infectious diseases including tuberculosis, cholera (though the Vibrio cholerae, bacterium itself was discovered by Filippo Pacini in 1854), and anthrax, he is regarded as one of the main founders of modern bacteriology. As such he is popularly nicknamed the father of microbiology (with Louis Pasteur), and as the father of medical bacteriology. His discovery of the anthrax bacterium (''Bacillus anthracis'') in 1876 is considered as the birth of modern bacteriology. His discoveries directly provided proofs for the germ theory of diseases, and the scientific basis of public health. While working as a private physician, Koch developed many innovative techniques in microbiology. He was the first to use the oil immersion lens, Condenser (optics), condenser, and microphotography in microscopy. His invention of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhodophyta
Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are found in the Florideophyceae ( class), and mostly consist of multicellular, marine algae, including many notable seaweeds. Red algae are abundant in marine habitats but relatively rare in freshwaters. Approximately 5% of red algae species occur in freshwater environments, with greater concentrations found in warmer areas. Except for two coastal cave dwelling species in the asexual class Cyanidiophyceae, there are no terrestrial species, which may be due to an evolutionary bottleneck in which the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity. The red algae form a distinct group characterized by having eukaryotic cells without flagella and centrioles, chloroplasts th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agarophyte
An agarophyte is a seaweed, typically a red alga, that produces the hydrocolloid agar in its cell walls. This agar can be harvested commercially for use in biological experiments and culturing. In some countries (especially in the developing world), the harvesting of agarophytes, either as natural stocks or a cultivated crop, is of considerable economic importance. Notable genera of commercially exploited agarophytes include ''Gracilaria'' and ''Gelidium'' (such as ''Gelidium amansii'' and ''Gelidium corneum''). References Seaweeds {{Rhodophyta-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gracilaria
''Gracilaria'' is a genus of red algae (Rhodophyta) notable for its economic importance as an agarophyte, as well as its use as a food for humans and various species of shellfish. Various species within the genus are cultivated among Asia, South America, Africa and Oceania. Taxonomy ''Gracilaria'' contains the following subtaxa: *''Gracilaria abbottiana'' M.D.Hoyle *''Gracilaria abyssalis'' Gurgel & Yoneshigue-Valentin *''Gracilaria aculeata'' (Hering) Papenfuss *''Gracilaria aggregata'' Hooker f. & Harvey *''Gracilaria ambigua'' Greville *'' Gracilaria apiculata'' P.Crouan & H.Crouan ** ''Gracilaria apiculata'' subsp. ''candelabriformis'' Gurgel, Fredericq & J.N.Norris *''Gracilaria apiculifera'' J.Agardh ** ''Gracilaria arcuata'' f. ''rhizophora'' Børgesen ** ''Gracilaria arcuata'' var. ''attenuata'' Umamaheswara Rao ** ''Gracilaria arcuata'' var. ''snackeyi'' Weber Bosse *''Gracilaria arcuata'' Zanardini *'' Gracilaria armata'' (C.Agardh) Greville *''Gracilaria articulata'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ogonori
''Gracilaria'' is a genus of red algae (Rhodophyta) notable for its economic importance as an agarophyte, as well as its use as a food for humans and various species of shellfish. Various species within the genus are cultivated among Asia, South America, Africa and Oceania. Taxonomy ''Gracilaria'' contains the following subtaxa: *'' Gracilaria abbottiana'' M.D.Hoyle *''Gracilaria abyssalis'' Gurgel & Yoneshigue-Valentin *''Gracilaria aculeata'' (Hering) Papenfuss *''Gracilaria aggregata'' Hooker f. & Harvey *''Gracilaria ambigua'' Greville *'' Gracilaria apiculata'' P.Crouan & H.Crouan ** ''Gracilaria apiculata'' subsp. ''candelabriformis'' Gurgel, Fredericq & J.N.Norris *''Gracilaria apiculifera'' J.Agardh ** ''Gracilaria arcuata'' f. ''rhizophora'' Børgesen ** ''Gracilaria arcuata'' var. ''attenuata'' Umamaheswara Rao ** ''Gracilaria arcuata'' var. ''snackeyi'' Weber Bosse *''Gracilaria arcuata'' Zanardini *'' Gracilaria armata'' (C.Agardh) Greville *''Gracilaria articulata'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substrate (biology)
In biology, a substrate is the surface on which an organism (such as a plant, fungus, or animal) lives. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock (its substrate) can be itself a substrate for an animal that lives on top of the algae. Inert substrates are used as growing support materials in the hydroponic cultivation of plants. In biology substrates are often activated by the nanoscopic process of substrate presentation. In agriculture and horticulture * Cellulose substrate * Expanded clay aggregate (LECA) * Rock wool * Potting soil * Soil In animal biotechnology Requirements for animal cell and tissue culture Requirements for animal cell and tissue culture are the same as described for plant cell, tissue and organ culture (In Vitro Culture Techniques: The Biotechnological Principles). Desirable requirements are (i) air conditioning of a room, (ii) hot room with temperature recorder, (iii) microsc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tokoroten
is a dish in Japanese cuisine made from agarophytes. Tokoroten has been eaten by the Japanese for over a thousand years. Tokoroten is thought to have been introduced to Japan from China during the Nara period. Tokoroten was traditionally made by boiling ''tengusa'' ('' Gelidium amansii'') and then allowing the mixture to congeal into a jelly. Tokoroten was a popular snack during the summertime in Edo (Tokyo) during the Edo period. It was originally made to be eaten immediately and was commonly sold around factories. In the 17th century, it was discovered that freezing tokoroten would result in a stable and dry product known as ''kanten'' (agar). While tokoroten can be made from ''kanten'' based on seaweeds such as ''tengusa'' ('' Gelidiaceae'') and '' ogonori'' ('' Gracilaria''), today commercially produced ''kanten'' is mostly made from ''ogonori''. Pressed against a device, the jelly is shaped into noodles. Unlike gelatin desserts, tokoroten has a firmer texture. Tokoroten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gelidiaceae
The Gelidiaceae is a small family of red algae containing eight genera. Many species of this algae are used to make agar. Uses Agar can be derived from many types of red seaweeds, including those from families such as ''Gelidiaceaae'', ''Gracilariaceae'', '' Gelidiellaceae'' and '' Pterocladiaceae''. It is a polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with ... located in the inner part of the red algal cell wall. It is used in food material, medicines, cosmetics, therapeutic and biotechnology industries.Mohammed Kuddus and Roohi (editors) References Red algae families Edible algae Taxa named by Friedrich Traugott Kützing {{Rhodophyta-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
