Term
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Definition
| Reproduction by cell division of a single-celled organism. |
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Term
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Definition
| A community of microorganisms embedded in a polysaccharide matrix, forming a highly resistant coating on almost any moist surface. |
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Term
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Definition
| The production of light by biochemical processes in an organism. |
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Term
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Definition
| An organism that must obtain both carbon and energy from organic substances. (Contrast with chemolithotroph, photoautotroph, photoheterotroph.) |
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Term
| chemolithotroph [Gk. lithos: stone, rock] |
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Definition
| An organism that uses carbon dioxide as a carbon source and obtains energy by oxidizing inorganic substances from its environment. (Contrast with chemoheterotroph, photoautotroph, photoheterotroph.) |
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Term
| chlamydias (Chlamydiae) [38] |
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Definition
| A group of very small Gram-negative bacteria; they live as intracellular parasites of other organisms. |
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Term
| crenarchaeotes (Crenarchaeota) [43] |
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Definition
| A major and diverse group of archaeans [3], defined on the basis of rRNA base sequences. Many are extremophiles (inhabit extreme environments), but the group may also be the most abundant archaeans in the marine environment. |
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Term
| cyanobacteria (Cyanobacteria) [40] |
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Definition
| A group of unicellular, colonial, or filamentous bacteria that conduct photosynthesis using chlorophyll a. |
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Term
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Definition
| Organisms that metabolize organic compounds in debris and dead organisms, releasing inorganic material; found among the bacteria, protists, and fungi. See detritivore. |
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Term
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Definition
| Metabolic activity by which nitrate and nitrite ions are reduced to form nitrogen gas; carried on by certain soil bacteria. |
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Term
| euryarchaeotes (Euryachaeota) [44] |
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Definition
| A major group of archaeans [3], diagnosed on the basis of rRNA sequences. Includes many methanogens, extreme halophiles, and thermophiles. |
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Term
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Definition
| Highly toxic proteins released by living, multiplying bacteria. |
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Term
| facultative anaerobes (alternatively, facultative aerobes) |
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Definition
| Prokaryotes that can shift their metabolism between anaerobic and aerobic operations depending on the presence or absence of O2. |
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Term
| flagellum (fla jell´ um) (plural: flagella) [L. flagellum: whip] |
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Definition
| Long, whiplike appendage that propels cells. Prokaryotic flagella differ sharply from those found in eukaryotes. |
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Term
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Definition
| A differential purple stain useful in characterizing bacteria. The peptidoglycan-rich cell walls of Gram-positive bacteria stain purple; cell walls of Gram-negative bacteria generally stain orange. |
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Term
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Definition
| A large, thick-walled cell in the filaments of certain cyanobacteria; performs nitrogen fixation. |
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Term
| high-GC Gram-positives (Actinobacteria) [39] |
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Definition
| Gram-positive bacteria with a relatively high G+C/A+T ratio of their DNA, with a filamentous growth habit. |
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Term
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Definition
| A set of rules for establishing that a particular microorganism causes a particular disease. |
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Term
| korarchaeotes (Korarchaeota) |
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Definition
| A group of archaeans [3] known only by evidence from nucleic acids derived from hot springs. Its phylogenetic relationships within the Archaea are unknown. |
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Term
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Definition
| The transfer of genes from one species to another, common among bacteria and archaea. |
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Term
| low-GC Gram-positives (Firmicutes) [41] |
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Definition
| A diverse group of bacteria [2] with a relatively low G+C/A+T ratio of their DNA, often but not always Gram-positive, some producing endospores. |
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Term
| nanoarchaeotes (Nanoarchaeota) |
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Definition
| A hypothetical group of extremely small, thermophilic archaeans [3] with a much-reduced genome. The only described example can survive only when attached to a host organism. |
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Term
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Definition
| The oxidation of ammonia to nitrite and nitrate ions, performed by certain soil bacteria. |
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Term
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Definition
| Conversion of nitrogen gas to ammonia, which makes nitrogen available to living things. Carried out by certain prokaryotes, some of them free-living and others living within plant roots. |
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Term
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Definition
| An anaerobic prokaryote that cannot survive exposure to O2. |
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Term
| pathogen (path´ o jen) [Gk. pathos: suffering + genesis: source] |
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Definition
| An organism that causes disease. |
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Term
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Definition
| The cell wall material of many bacteria, consisting of a single enormous molecule that surrounds the entire cell. |
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Term
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Definition
| An organism that obtains energy from light and carbon from carbon dioxide. (Contrast with chemolithotroph, chemoheterotroph, photoheterotroph.) |
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Term
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Definition
| An organism that obtains energy from light but must obtain its carbon from organic compounds. (Contrast with chemolithotroph, chemoheterotroph, photoautotroph.) |
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Term
| proteobacteria (Proteobacteria) [42] |
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Definition
| A large and extremely diverse group of Gram-negative bacteria that includes many pathogens, nitrogen fixers, and photosynthesizers. Includes the alpha, beta, gamma, delta, and epsilon proteobacteria. |
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Term
| spirochetes (Spirochaetes) [37] |
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Definition
| Motile, Gram-negative bacteria with a helically coiled structure and characterized by axial filaments. |
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Term
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Definition
| Any asexual reproductive cell capable of developing into an adult organism without gametic fusion. In plants, haploid spores develop into gametophytes, diploid spores into sporophytes. In prokaryotes, a resistant cell capable of surviving unfavorable periods. |
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Term
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Definition
| Nonreproductive, nonflowering, or asexual. |
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