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Francisella Tularensis Spp.
''Francisella'' is a genus of Gram-negative bacterium, bacteria. They are small coccobacillus, coccobacillary or bacillus, rod-shaped, nonMotility, motile organisms, which are also facultative intracellular parasites of macrophages. Strict Aerobic organism, aerobes, ''Francisella'' colonies bear a morphological resemblance to those of the genus ''Brucella''. Some ''Francisella'' species are pathogenic bacteria but some others are endosymbionts of ticks. Ticks do not use any other food source than vertebrate blood and therefore ingest high levels of protein, iron and salt, but few vitamins. To overcome these nutritional deficiencies, ticks have evolved obligate interactions with nutritional endosymbionts, including ''Francisella'' endosymbionts. Their experimental elimination typically results in decreased tick survival, molting, fecundity and egg viability, as well as in physical abnormalities, which all are fully restored with an oral supplement of B vitamins. The genome sequenci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francisella Tularensis
''Francisella tularensis'' is a pathogenic species of Gram-negative coccobacillus, an aerobic bacterium. It is nonspore-forming, nonmotile, and the causative agent of tularemia, the pneumonic form of which is often lethal without treatment. It is a fastidious, facultative intracellular bacterium, which requires cysteine for growth. Due to its low infectious dose, ease of spread by aerosol, and high virulence, ''F. tularensis'' is classified as a Tier 1 Select Agent by the U.S. government, along with other potential agents of bioterrorism such as ''Yersinia pestis, Bacillus anthracis'', and Ebola virus. When found in nature, ''Francisella tularensis'' can survive for several weeks at low temperatures in animal carcasses, soil, and water. In the laboratory, ''F. tularensis'' appears as small rods (0.2 by 0.2 µm), and is grown best at 35–37 °C. History This species was discovered in ground squirrels in Tulare County, California in 1911. ''Bacterium tularense'' was soon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
