A division of the kingdom Prokaryotae consisting of unicellular or filamentous bacteria that are either nonmotile or possess a gliding motility, reproduce by binary fission, and perform photosynthesis with the production of oxygen. These blue-green bacteria were formerly referred to as blue-green algae. SYN: Cyanophyceae.
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Cy·a·no·bac·te·ria (si″ə-no-bak-tērґe-ə) [cyano- + bacteria] the blue-green bacteria (formerly called blue-green algae), a phylum of unicellular or filamentous phototrophic organisms of the domain Bacteria that use water as an electron donor and produce oxygen in the presence of light. Cells are enclosed by a rigid wall containing peptidoglycan, are generally motile, and reproduce by fission. Photopigments include chlorophyll a and phycobilin proteins. Cyanobacteria are the only organisms that fix both carbon dioxide (in the presence of light) and nitrogen. Most species are photosynthetic and many are strong nitrogen fixers. Several species are common causes of water pollution and are often used as indicators of eutrophication of lakes and streams; see cyanobacteria poisoning, under poisoning.Medical dictionary. 2011.