Obligate intracellular bacteria transmitted by ticks may cause Rocky Mountain spotted fever and typhus Gram-negative, highly pleomorphic bacteria (may be cocci, rods, or threads) Nitrogen-fixing bacteria that live in soil and form symbiotic relationship with roots of legumes (e.g., clover, alfalfa, and beans) Gram-negative, rectangular bacilli with rounded ends forming clusters Obligatory intracellular bacteria can be transported from cell to cell transmitted by ticks cause ehrlichiosis (destruction of white blood cells and inflammation) in humans and dogs Very small, gram-negative, coccoid or ovoid bacteria Obligatory intracellular bacteria cause Q fever potential for use as biological weapon Used in studies on cellular adaptation and differentiation because of its peculiar life cycle (during cell division, forms “swarm” cells and “stalked” cells) Gram-negative, small, flagellated coccobacillusįacultative intracellular bacteria, transmitted by contaminated milk from infected cows, cause brucellosis in cattle and humans Gram-negative, pleomorphic, flagellated coccobacillusįacultative intracellular bacteria, transmitted by lice and fleas, cause trench fever and cat scratch disease in humans rickettsii infects ticks and can be transmitted to humans via a bite from an infected tick ( Figure 4.4). rickettsii causes Rocky Mountain spotted fever, a life-threatening form of meningoencephalitis (inflammation of the membranes that wrap the brain). include a number of serious human pathogens. They cannot synthesize their own adenosine triphosphate (ATP), and, therefore, rely on cells for their energy needs. When not growing inside a host cell, Rickettsia are metabolically inactive outside the host cell. Some species are characterized as oligotrophs, organisms capable of living in low-nutrient environments such as deep oceanic sediments, glacial ice, or deep undersurface soil.Īmong the Alphaproteobacteria are rickettsias, obligate intracellular pathogens, that require part of their life cycle to occur inside other cells called host cells. The first class of Proteobacteria is the Alphaproteobacteria, many of which are obligate or facultative intracellular bacteria. The Proteobacteria are further divided into five classes: Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, and Epsilonproteobacteria ( Appendix D). It includes many bacteria that are part of the normal human microbiota as well as many pathogens. 10 This phylum of gram-negative bacteria subsequently received the name Proteobacteria. In 1987, the American microbiologist Carl Woese (1928–2012) suggested that a large and diverse group of bacteria that he called “purple bacteria and their relatives” should be defined as a separate phylum within the domain Bacteria based on the similarity of the nucleotide sequences in their genome.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |