Query: NC_017216:1356930 Bifidobacterium animalis subsp. lactis BLC1, complete genome
Lineage: Bifidobacterium animalis; Bifidobacterium; Bifidobacteriaceae; Bifidobacteriales; Actinobacteria; Bacteria
General Information: Representatives of this genus naturally colonize the human gastrointestinal tract (GIT) and are important for establishing and maintaining homeostasis of the intestinal ecosystem to allow for normal digestion. Their presence has been associated with beneficial health effects, such as prevention of diarrhea, amelioration of lactose intolerance, or immunomodulation. The stabilizing effect on GIT microflora is attributed to the capacity of bifidobacteria to produce bacteriocins, which are bacteriostatic agents with a broad spectrum of action, and to their pH-reducing activity. Most of the ~30 known species of bifidobacteria have been isolated from the mammalian GIT, and some from the vaginal and oral cavity. All are obligate anaerobes belonging to the Actinomycetales, branch of Gram-positive bacteria with high GC content that also includes Corynebacteria, Mycobacteria, and Streptomycetes. Bifidobacterium animalis and Bifidobacterium lactis were originally considered to be separate species. Recent studies evaluating the DNA relatedness and phenotypic similarities of these species has determined that they represent a single species.
Subject: NC_003888:5550582 Streptomyces coelicolor A3(2), complete genome
Lineage: Streptomyces coelicolor; Streptomyces; Streptomycetaceae; Actinomycetales; Actinobacteria; Bacteria
General Information: Well-studied antiobiotic-producing bacterium. These bacteria are widely distributed in nature, especially in the soil. 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. This bacterium is a soil-dwelling filamentous organism responsible for producing more than half of the known natural antibiotics. It is a well-studied species of Streptomyces and genetically is the best known representative.