Pre_GI: SWBIT SVG BLASTP

Query: NC_012943:2103662 Mycobacterium tuberculosis KZN 1435 chromosome, complete genome

Lineage: Mycobacterium tuberculosis; Mycobacterium; Mycobacteriaceae; Actinomycetales; Actinobacteria; Bacteria

General Information: M. tuberculosis strain KZN 1435 was isolated from a patient in KwaZulu-Natal, South Africa. This strain is multidrug-resistant (resistant to isoniazid and rifampin). This bacterium is the causative agent of tuberculosis - a chronic infectious disease with a growing incidence worldwide. This species is responsible for more morbidity in humans than any other bacterial disease. It infects 1.7 billion people a year (~33% of the entire world population) and causes over 3 million deaths/year. This bacterium does not form a polysaccharide capsule, and is an extremely slow growing obligate aerobe. The sluggish growth rate is a result of the tough cell wall that resists the passage of nutrients into the cell and inhibits waste products to be excreted out of the cell. The specialized cell envelope of this organism resembles a modified Gram positive cell wall. The envelope contains the typical polypeptide layer, the peptidoglycan layer, and free lipids. It also contains complex fatty acids, such as mycolic acids, that cause the waxy appearance and impermeability of the envelope. These acids are found bound to the cell envelope, but also form cord factors when linked with a carbohydrate component to form a cord-like structure. These fatty acid-carbohydrate complexes inhibit phago-lysosome fusion and are often considered to be indicators of virulent strains. The cell envelope also includes adhesins and aggressions, but does not contain any known toxins. Primary infection occurs by inhalation of the organism in droplets that are aerosolized by an infected person. The organism initially replicates in cells of the terminal airways, after which it is taken up by, and replicates in, alveolar macrophages. Macrophages distribute the organism to other areas of the lungs and the regional lymph nodes. Once a cell-mediated hypersensitivity immune response develops, replication of the organism decreases and the bacteria become restricted to developing granulomas.

Subject: NC_010572:7304290 Streptomyces griseus subsp. griseus NBRC 13350, complete genome

Lineage: Streptomyces griseus; Streptomyces; Streptomycetaceae; Actinomycetales; Actinobacteria; Bacteria

General Information: Soil bacterium producing an antituberculosis agent. The characteristic earthy smell of freshly plowed soil is actually attributed to the aromatic terpenoid geosmin produced by species of Streptomyces. There are currently 364 known species of this genus, many of which are the most important industrial producers of antibiotics and other secondary metabolites of antibacterial, antifungal, antiviral, and antitumor nature, as well as immunosuppressants, antihypercholesterolemics, etc. Streptomycetes are crucial in the soil environment because their diverse metabolism allows them to degrade the insoluble remains of other organisms, including recalcitrant compounds such as lignocelluloses and chitin. Streptomycetes produce both substrate and aerial mycelium. The latter shows characteristic modes of branching, and in the course of the streptomycete complex life cycle, these hyphae are partly transformed into chains of spores, which are often called conidia or arthrospores. An important feature in Streptomyces is the presence of type-I peptidoglycan in the cell walls that contains characteristic interpeptide glycine bridges. Another remarkable trait of streptomycetes is that they contain very large (~8 million base pairs which is about twice the size of most bacterial genomes) linear chromosomes with distinct telomeres. These rearrangements consist of the deletion of several hundred kilobases, often associated with the amplification of an adjacent sequence, and lead to metabolic diversity within the Streptomyces group. Sequencing of several strains of Streptomyces is aimed partly on understanding the mechanisms involved in these diversification processes.