|
|
|
|
|
|
Streptococcus is a genus of spherical, Gram-positive bacteria of the phylum Firmicutes. These bacteria grow in chains or pairs, with cell division occurring only along one axis. In this sense they are contrasted with Staphylococcus, which divides along several axes, generating a cluster of cells, which resemble clusters of grapes. Members of the genus Streptococcus which cause disease include: Group A Streptococci (Streptococcus pyogenes) which causes Group A streptococcal infection Group B Streptococci (Streptococcus agalactiae), also known as GBS, which causes meningitis in neonates and the elderly, with occasional systemic bacteremia. They can also colonise the female reproductive tract, increasing the risk for premature rupture of membranes and transmission to the child. While only 10 percent of TB infection progresses to TB disease, if untreated the death rate is 50 percent. TB infection begins when TB bacilli reach the pulmonary alveoli, from which they may spread to local lymph nodes, and then through the bloodstream to the more distant tissues and organs where TB disease is likely to develop: lung apices, peripheral lymph nodes, kidneys, brain, and bone. The bacterium causes a type IV immune hypersensitivity response. T-lymphocytes secrete cytokines and recruit and activate macrophages. These macrophages form spherical aggregates in the tissues called granulomas. A granuloma when viewed under the microscope by histology shows a central zone of large macrophagic cells surrounded by a zone of T-lymphocytes. Some of the macrophages fuse to form multinucleate giant cells termed Langerhans Giant cells. Tuberculosis is therefore classed as one of the granulomatous inflammatory conditions. Click on following items to see more information: Agrobacteria, Antibiotic, Antibiotic prophylaxis, Antibacterial, Bacilli, Bacillus subtilis, Bacterium, Bacterial, Phages, Bacteroides, C. botulinum, C. albicans, Cell suspension, Clostridium, Culture media, E. coli, E. coli, E. coli, E. coli, E. coli, Enterobacter, Fermentation, Yeast, Gram negative, Haemophilus, Lactococcus, Bacterium, Bacterial, Bacterium, Neisseria, Pichia, P. aeruginosa, Pseudomonas putida, Saccharomyces cerevisiae, Saccharomyces cerevisiae, Salmonella typhimurium, Bacteremia, S. aureus, Streptococcus, Streptococcus, Thermophilic, Yeast Bordetella is a genus of proteobacteria. Members of the species B. pertussis and occasionally B. parapertussis cause pertussis or whooping cough in humans. Several other species cause similar disease in other mammals, such as B. bronchiseptica, and in birds, such as B. avium and B. hinzii. Sphingomonas was defined in 1990 as a group of Gram-negative, rod-shaped, chemoheterotrophic, strictly aerobic bacteria that possess ubiquinone 10 as the major respiratory quinone, contain glycosphingolipids (GSLs) instead of lipopolysaccharide in their cell envelopes, and typically produce yellow-pigmented colonies. By 2001, the genus included more than 20 species that were quite diverse in terms of their phylogenetic, ecological, and physiological properties. As a result, the Sphingomonas were subdivided into four genera: Sphingomonas, Sphingobium, Novosphingobium and Sphingopyxis. The sulfate-reducing have been treated as phenotypic group, together with the other sulfur-reducing bacteria, for identification purposes. They are found in several different phylogenetic lines. Three lines are included among the Proteobacteria, all in the delta subgroup: Desulfobacterales Desulfovibrionales Syntrophobacterales A fourth group including thermophiles is given its own phylum, the Thermodesulfobacteria. The remaining sulfate-reducers are included with other bacteria among the Nitrospirae and the gram-positive Peptococcaceae - for instance Thermodesulfovibrio and Desulfotomaculum, respectively. There is also a single genus of Archaea capable of sulfate reduction, Archaeoglobus.
|
© 2005
Transgalactic Ltd (manufacturer of Bioscreen C software) |
Privacy Statement | P.O. Box
1393, 00101 Helsinki, Finland,
Last modified: May 25, 2005
| ||||||
