|
Enrichment Culture
Enrichment culture is the use of certain growth media to favor the growth of a particular microorganism over others, enriching a sample for the microorganism of interest. This is generally done by introducing nutrients or environmental conditions that only allow the growth of an organism of interest. Enrichment cultures are used to increase a small number of desired organisms to detectable levels. This allows for the detection and identification of microorganisms with a variety of nutritional needs. Enrichment cultures are often used for soil and fecal samples. History The microbiologist (and botanist) Martinus Beijerinck is credited with developing the first enrichment cultures. Sergei Winogradsky also experimented on bacteria using different cultures. Examples Media with a high salt concentration will select for halophiles. Selenite broth is used to selectively isolate Salmonella species. Alkaline Peptone Water is used for the cultivation of vibrio. Both these examples are c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Growth Media
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] |
Microorganism
A microorganism, or microbe, is an organism of microscopic scale, microscopic size, which may exist in its unicellular organism, single-celled form or as a Colony (biology)#Microbial colonies, colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in Jain literature authored in 6th-century BC India. The scientific study of microorganisms began with their observation under the microscope in the 1670s by Anton van Leeuwenhoek. In the 1850s, Louis Pasteur found that microorganisms caused food spoilage, debunking the theory of spontaneous generation. In the 1880s, Robert Koch discovered that microorganisms caused the diseases tuberculosis, cholera, diphtheria, and anthrax. Microorganisms are extremely diverse, representing most unicellular organisms in all three domains of life: two of the three domains, Archaea and Bacteria, only contain microorganisms. The third domain, Eukaryota, includes all multicellular o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Martinus Beijerinck
Martinus Willem Beijerinck (, 16 March 1851 – 1 January 1931) was a Dutch microbiologist and botanist who was one of the founders of virology and environmental microbiology. He is credited with the co-discovery of viruses A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almo ... (1898), which he called "''contagium vivum fluidum''". Life Early life and education Born in Amsterdam, Beijerinck studied at the Technical School of Delft, where he was awarded the degree of biology in 1872. He obtained his Doctor of Science degree from the University of Leiden in 1877. At the time, Delft, then a List of institutions using the term "institute of technology" or "polytechnic", Polytechnic, did not have the right to confer doctorates, so Leiden did this for them. He became a teacher in microb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sergei Winogradsky
Sergei Nikolaevich Winogradsky (; ; , Kyiv – 24 February 1953, Brie-Comte-Robert), also published under the name Sergius Winogradsky, was a Ukrainian and Russian microbiologist, ecologist and soil science, soil scientist who pioneered the Biogeochemical cycle, cycle-of-life concept. Winogradsky discovered the first known form of lithotrophy during his research with ''Beggiatoa'' in 1887. He reported that ''Beggiatoa'' oxidized hydrogen sulfide (H2S) as an energy source and formed intracellular sulfur droplets. This research provided the first example of lithotrophy, but not autotrophy. Born in the capital of present-day Ukraine, his legacy is also celebrated by this nation. His research on nitrifying bacteria would report the first known form of chemotroph, chemoautotrophy, showing how a lithotroph carbon fixation, fixes carbon dioxide (CO2) to make organic compounds. He is best known in school science as the inventor of the Winogradsky column technique for the study of sedim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halophile
A halophile (from the Greek word for 'salt-loving') is an extremophile that thrives in high salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ... concentrations. In chemical terms, halophile refers to a Lewis acids and bases, Lewis acidic species that has some ability to extract halides from other chemical species. While most halophiles are classified into the domain Archaea, there are also bacterial halophiles and some Eukaryote, eukaryotic species, such as the alga ''Dunaliella salina'' and fungus ''Wallemia ichthyophaga''. Some well-known species give off a red color from carotenoid compounds, notably bacteriorhodopsin. Halophiles can be found in water bodies with salt concentration more than five times greater than that of the ocean, such as the Great Salt Lake in Utah, Owe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 pink coloured pentahydrate Na2SeO3(H2O)5 is the most common water-soluble selenium compound. Synthesis and fundamental reactions Sodium s ... 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: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmonella
''Salmonella'' is a genus of bacillus (shape), rod-shaped, (bacillus) Gram-negative bacteria of the family Enterobacteriaceae. The two known 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 2,650 serotypes. ''Salmonella'' was named after Daniel Elmer Salmon (1850–1914), an American veterinary surgeon. ''Salmonella'' species are non-Endospore, spore-forming, predominantly motility, motile enterobacteriaceae, enterobacteria with cell diameters between about 0.7 and 1.5 micrometre, 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 Redox, oxidation and reduction reactions, using organic sources. They are also facultative aerobic organism, facultative anaerobes, capable of generating adenosine triphosphate with oxygen ("aerobically") ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptone Water
Peptone water is a microbial growth medium composed of peptic digest of animal tissue and sodium chloride. The pH of the medium is 7.2±0.2 at 25 °C and is rich in tryptophan. Peptone water is also a non-selective broth medium which can be used as a primary enrichment medium for the growth of bacteria. References Growth media 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''. Differe ... Microbiological media {{Biology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibrio
''Vibrio'' is a genus of Gram-negative bacteria, which have a characteristic curved-rod (comma) shape, several species of which can cause foodborne infection or soft-tissue infection called Vibriosis. Infection is commonly associated with eating undercooked seafood. Being highly salt tolerant and unable to survive in freshwater, ''Vibrio'' spp. are commonly found in various salt water environments. ''Vibrio'' spp. are facultative anaerobes that test positive for oxidase and do not form spores. All members of the genus are motile. They are able to have polar or lateral flagellum with or without sheaths. ''Vibrio'' species typically possess two chromosomes, which is unusual for bacteria. Each chromosome has a distinct and independent origin of replication, and are conserved together over time in the genus. Recent phylogenies have been constructed based on a suite of genes (multilocus sequence analysis). O. F. Müller (1773, 1786) described eight species of the genus ''Vibrio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbiological Culture
A microbiological culture, or microbial culture, is a method of multiplying microorganism, microbial organisms by letting them reproduce in predetermined culture medium under controlled laboratory conditions. Microbial cultures are foundational and basic diagnostic methods used as research tools in molecular biology. The term ''culture'' can also refer to the microorganisms being grown. Microbial cultures are used to determine the type of organism, its abundance in the sample being tested, or both. It is one of the primary diagnostic methods of microbiology and used as a tool to determine the cause of infection, infectious disease by letting the agent multiply in a predetermined medium. For example, a throat culture is taken by scraping the lining of tissue in the back of the throat and blotting the sample into a medium to be able to screen for harmful microorganisms, such as ''Streptococcus pyogenes'', the causative agent of strep throat. Furthermore, the term culture is more ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auxanography
Auxanography is the study of the effects of changes in environment on the growth of microorganisms, by means of auxanograms. It was first devised by BeijerinckBeijerinck, M. W. 1889. L'auxanographie, ou la méthode de l'hydrodiffusion dans la gélatine appliquée aux recherches microbiologiques. Arch. Néerl. Sc. 23:367-372. for testing the effect of various nutrient media upon bacteria.JANA GANA MANA – auxanography The bacteria are plated out in a medium known to be poorly adapted for their , and then drops of the tested solutions are added to the surface of the plate. If the requisite nutrient has been added, the bacteria will develop rapidly in these spots ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enriched 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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
