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, n. (Microbiol.) A group of single-celled microorganisms including the methanogens and some halophiles and thermoacidophiles, recognized in the 1970's by C. R. Woese and his colleagues as being a distinct group on the basis of RNA sequences, cell walls, and coenzymes differing from those of other microbes. It is believed to be an ancient form of living organism that evolved separately from the eubacteria and blue-green algae. It is classified as a separate kingdom by some taxonomists. See also The Archaebacteria. [ PJC ]

‖n.; pl. Coccobacteria [ NL., fr. Gr. &unr_; a grain + NL. bacterium. So called from its round shape. ] (Biol.) One of the round variety of bacteria, a vegetable organism, generally less than a thousandth of a millimeter in diameter. [ 1913 Webster ]

pl. [ from the pigment phycocyanin. ] any of a group of photosynthetic autotrophic prokaryotic microorganisms possessing characteristics of both bacteria and plants. When classed as bacteria, they are assigned to the Cyanobacteria; when classed as plants, they are assigned to the Cyanophyta. They were earlier named blue-green algae, a term less used now in technical discussions. Since the chlorophyll within the cyanobacteria is diffused throughout the cell, rather than being contained in chloroplasts, they are no longer thought of as true plants. [ PJC ]

‖n. pl. [ Gr. desmo`s bond + E. bacteria. ] See Microbacteria. [ 1913 Webster ]

n. pl. rod-shaped gram-negative bacteria of the family Enterobacteriaceae; most occur normally or pathogenically in intestines of humans and other animals; some, such as those of the genus Erwinia, are found in plants.
Syn. -- enteric bacteria, enterics. [ WordNet 1.5 ]

prop. n. (Microbiol.) a natural family of rod-shaped gram-negative bacteria, most of which occur normally or pathogenically in intestines of humans and other animals, and some of which grow in plants. The type genus is Escherichia. They are aerobic and facultatively anaerobic, and may be motile or non-motile. Most are easily cultured on artificial growth media. Both pathogenic and non-pathogenic strains exist. [ PJC ]

a. Of or pertaining to the enterobacteria. [ PJC ]

n. one of the enterobacteria; a member of the family Enterobacteriaceae.
Syn. -- enteric bacterium, enteric. [ PJC ]

n.; pl. halobacteria or halobacters Any halophilic bacterium of the archaebacteria group, expecially of the genera Halobacterium and Halococcus, which live in saline environments such as the Dead Sea or salt flats.
Syn. -- halobacteria, halobacter. [ WordNet 1.5 +PJC ]

‖n. pl. [ NL. See Micro-, and Bacterium. ] (Biol.) In the classification of Cohn, one of the four tribes of Bacteria. [ 1913 Webster ]

☞ In this classification bacteria are divided into four tribes: 1. Spherobacteria, or spherical bacteria, as the genus Micrococcus. 2. Microbacteria, or bacteria in the form of short rods, including the genus Bacterium. 3. Desmobacteria, or bacteria in straight filaments, of which the genus Bacillus is a type. 4. Spirobacteria, or bacteria in spiral filaments, as the genus Vibrio. [ 1913 Webster ]

n. pl. A group of rod-shaped bacteria, some saprophytic or causing diseases.
Syn. -- mycobacterium. [ WordNet 1.5 ]

n.; pl. mycobacteria Any of various rod-shaped bacteria, some saprophytic or causing diseases. [ WordNet 1.5 ]

prop. n. (Microbiol.) One genus of myxobacteria. [ PJC +PJC ]

prop. n. A family of bacteria living mostly in soils and on dung; called also Polyangiaceae.
Syn. -- Polyangiaceae, family Polyangiaceae, family Myxobacteriaceae. [ WordNet 1.5 ]

n.; pl. myxobacteria A type of bacteria that form colonies in self-produced slime; they inhabit moist soils or decaying plant matter or animal waste.
Syn. -- myxobacterium, myxobacter, gliding bacteria, slime bacteria. [ WordNet 1.5 ]

prop. n. A genus of rod-shaped soil bacteria.
Syn. -- genus Nitrobacter. [ WordNet 1.5 ]

n. Soil bacteria that convert nitrites to nitrates.
Syn. -- nitric bacteria. [ WordNet 1.5 ]

prop. n. A natural family of usually rod-shaped bacteria that oxidize ammonia or nitrites: nitrobacteria.
Syn. -- family Nitrobacteriaceae. [ WordNet 1.5 ]

‖n. [ NL. See Photo-, and Bacterium. ] (Bacteriol.) A genus including certain comma-shaped marine bacteria which emit bluish or greenish phosphorescence. Also, any microorganism of this group. [ Webster 1913 Suppl. ]

n. pl. [ Pseudo- + bacteria. ] (Biol.) Microscopic organic particles, molecular granules, powdered inorganic substances, etc., which in form, size, and grouping resemble bacteria. [ 1913 Webster ]

The globules which divide and develop in form of chains are organized beings; when this does not occur, we are dealing with pseudobacteria. Sternberg. [ 1913 Webster ]

‖n. pl.; sing. Spherobacterium /sing>. [ NL. See Sphere, and Bacterium. ] (Biol.) See the Note under Microbacteria. [ 1913 Webster ]

‖n. pl.; sing. Spirobacterium /sing>. [ NL. See 4th Spire, and Bacterium. ] (Biol.) See the Note under Microbacteria. [ 1913 Webster ]