Dictionary:
clos·trid·i·um (klŏ-strĭd'ē-əm)  |
[New Latin Clōstridium, genus name, from Greek klōstēr, klōstr-, spindle, from klōthein, to spin.]
clostridial clos·trid'i·al (-əl) adj.| 5min Related Video: clostridium |
| Britannica Concise Encyclopedia: clostridium |
For more information on clostridium, visit Britannica.com.
| Sci-Tech Encyclopedia: Clostridium |
A genus of bacteria comprising large anaerobic spore-forming rods that usually stain gram-positive. Most species are anaerobes, but a few will grow minimally in air at atmospheric pressure.
The clostridia are widely distributed in nature, and are present in the soil and in the intestinal tracts of humans and animals. They usually live a saprophytic existence, and play a major role in the degradation of organic material in the soil and other nature environments. A number of clostridia release potent exotoxins and are pathogenic for humans and animals. Among the human pathogens are the causative agents of botulism (Clostridium botulinum), tetanus (C. tetani), gas gangrene (C. perfringens), and an antibiotic-associated enterocolitis (C. difficile). See also Anaerobic infection; Botulism; Toxin.
Clostridial cells are straight or slightly curved rods, 0.3–1.6 micrometers wide and 1–14 μm long. They may occur singly, in pairs, in short or long chains, or in helical coils. The length of the cells of the individual species varies according to the stage of growth and growth conditions. Most clostridia are motile with a uniform arrangement of flagella. See also Cilia and flagella.
The endospores produced by clostridia are dormant structures capable of surviving for prolonged periods of time, and have the ability to reestablish vegetative growth when appropriate environmental conditions are provided. The spores of clostridia are oval or spherical and are wider than the vegetative bacterial cell. Among the distinctive forms are spindle-shaped organisms, club-shaped forms, and tennis racket-shaped structures:
Clostridia are obligate anaerobes: they are unable to use molecular oxygen as a final electron acceptor and generate their energy solely by fermentation. Clostridia exhibit varying degrees of intolerance of oxygen. Some species are sensitive to oxygen concentrations as low as 0.5%, but most species can tolerate concentrations of 3–5%. The sensitivity of clostridia to oxygen restricts their habitat to anaerobic environments; habitats that contain large amounts of organic matter provide optimal conditions for their growth and survival.
A primary property of all species of Clostridium is their inability to carry out a dissimilatory reduction of sulfate. Most species are chemoorganotrophic. The substrate spectrum for the genus as a whole is very broad and includes a wide range of naturally occurring compounds. Extracellular enzymes are secreted by many species, enabling the organism to utilize a wide variety of complex natural substrates in the environment.
| Food and Nutrition: Clostridium |
A genus of bacteria, of which C. botulinum is responsible for botulism, a rare but often fatal form of food poisoning. It is found widely distributed in soil; during growth on favourable food materials, the organism synthesizes an extremely potent neurotoxin which is released into the food when the cell dies. The spores are extremely heat-resistant and their thermal death time is used as a minimum standard for processing foods with pH values higher than 4.5.
| Dental Dictionary: Clostridium |
A genus of spore-forming anaerobic bacteria of the Bacillaceae family.
| Veterinary Dictionary: clostridial |
Pertaining to or emanating from infection by Clostridium spp.
| Wikipedia: Clostridium |
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 SEM micrograph of Clostridium difficile colonies from a stool sample.
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C. acetobutylicum |
Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores.[1][2] Individual cells are rod-shaped, which gives them their name, from the Greek kloster (κλωστήρ) or spindle. These characteristics traditionally defined the genus, however many species originally classified as Clostridium have been reclassified in other genera.
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Clostridium consists of around 100 species[3] that include common free-living bacteria as well as important pathogens.[4] There are four main species responsible for disease in humans:
Honey sometimes contains spores of Clostridium botulinum, which may cause infant botulism in humans one year old and younger. The bacteria produce botulinum toxin, which eventually paralyzes the infant's breathing muscles.[9] Adults and older children can eat honey safely, because the clostridia do not compete well with the other rapidly growing bacteria present in the GI tract.
C. sordellii has been linked to the deaths of more than a dozen women after childbirth.[citation needed]
Clostridium is sometimes found in raw swiftlet birds' nests, a Chinese delicacy. Nests are washed in a sulfite solution to kill the bacteria before being imported to the U.S. [10]
Neurotoxin types Neurotoxin production is the unifying feature of the species C. botulinum. Seven types of toxins have been identified and allocated a letter (A-G). Most strains produce one type of neurotoxin but strains producing multiple toxins have been described. C. botulinum producing B and F toxin types have been isolated from human botulism cases in New Mexico and California. The toxin type has been designated Bf as the type B toxin was found in excess to the type F. Similarly, strains producing Ab and Af toxins have been reported. Organisms genetically identified as other Clostridium species have caused human botulism; Clostridium butyricum producing type E toxin and Clostridium baratii producing type F toxin. The ability of C. botulinum to naturally transfer neurotoxin genes to other clostridia is concerning, especially in the food industry where preservation systems are designed to destroy or inhibit only C. botulinum but not other Clostridium species.
C. thermocellum can utilize lignocellulosic waste and generate ethanol, thus making it a possible candidate for use in ethanol production. It also has no oxygen requirement and is thermophilic, reducing cooling cost.
C. acetobutylicum, also known as the Weizmann organism, was first used by Chaim Weizmann to produce acetone and biobutanol from starch in 1916 for the production of gunpowder and TNT.
The anaerobic bacterium C. ljungdahlii, recently discovered in commercial chicken wastes, can produce ethanol from single-carbon sources including synthesis gas, a mixture of carbon monoxide and hydrogen that can be generated from the partial combustion of either fossil fuels or biomass. Use of these bacteria to produce ethanol from synthesis gas has progressed to the pilot plant stage at the BRI Energy facility in Fayetteville, Arkansas.[11]
Fatty acids are converted by yeasts to long-chain dicarboxylic acids and then to 1,3-propanediol using Clostridium diolis.[citation needed]
Genes from C. thermocellum have been inserted into transgenic mice to allow the production of endoglucanase. The experiment was intended to learn more about how the digestive capacity of monogastric animals could be improved. Hall et al. published their findings in 1993.
Non-pathogenic strains of clostridia may help in the treatment of diseases such as cancer. Research shows that clostridia can selectively target cancer cells. Some strains can enter and replicate within solid tumours. Clostridia could, therefore, be used to deliver therapeutic proteins to tumours. This use of Clostridia has been demonstrated in a variety of preclinical models.[12]
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This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
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 | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| Britannica Concise Encyclopedia. Britannica Concise Encyclopedia. © 2006 Encyclopædia Britannica, Inc. All rights reserved. Read more |
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| Sci-Tech Encyclopedia. McGraw-Hill Encyclopedia of Science and Technology. Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved. Read more |
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| Food and Nutrition. A Dictionary of Food and Nutrition. Copyright © 1995, 2003, 2005 by A. E. Bender and D. A. Bender. All rights reserved. Read more |
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| Dental Dictionary. Mosby's Dental Dictionary. Copyright © 2004 by Elsevier, Inc. All rights reserved. Read more |
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| Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved. Read more |
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| Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Clostridium". Read more |
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