Cyanothece
| Generic name: CYANOTHECE Komárek, 1976. Arch. Protistenk. 118: 146. | ||||||||||
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| Type species:Cyanothece aeruginosa (Nägeli) Komárek 1976 | ||||||||||
| Description: Komárek & Anagnostidis (1998): Cells solitary or in twos after division (but sometimes aggregated in groups, clusters and mats), without gelatinous, envelopes or with a narrow (rarely wide), fine, hyaline, indistinct gelatinous margin around single cells. Cells widely oval to almost cylindrical with widely rounded ends, With length/width ratio = (1)1.2-1.8(2.6) : 1. Cell content with net-like (reticulate) keritomization (= irregular to radial arrangement of thylakoids, intrathylakoidal spaces). S-layer with p2 symmetry was found in C. aeruginosa. Net-like type of nucleoids. Involution cells irregular (never filamentous as in Synechococcus); (fig. 27d, 30). In several species motility was recorded. Komárek (1992): Unicellular; cells solitary or in irregular groups, oval, widely oval, ellipsoidal or almost cylindrical with widely rounded ends, mainly longer than 3 μm (up to 100 μm long) and (1.8)6-52 μm wide, without mucilage or with very fine and thin gelatinous layer around the cells. Cells with blue-green, olive-green or pinkish up to violet cell content, sometimes with dispersed prominent granules and with keritomized chromatoplasma (especially arranged groups of thylakpids). Cells immotile or slightly motile. GC-content of the DNA = approx. 42 mol. percent (acc. to Rippka et Cohen-Bazire 1983, only two strains studied). Involution cells irregular. |
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| Genotype differences, molecular data: | ||||||||||
| Reproduction strategies, life cycles, cell division: Komárek & Anagnostidis (1998): Cells always divide by binary fission (cleavage) into two morphologically equal, hemispherical daughter cells, in one plane, which is perpendicular to the longer cell axis in successive generations. Cells grow to the original size and shape before the next division takes place. Reproduction by cell division and succeeding separation of daugther cells. Komárek (1992):Reproduction by the cell division, perpendicular to one (longer) axis of the cell into two morphologically identical semiglobular daughter cells, which grow up to the original shape before the next division; the cells_divide repeatedly in only one plane in the succeeding generations. |
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| Ultrastructure: | ||||||||||
| Taxonomic position, higher hierarchy: Cyanophyceae, Chroococcales, Synechococcaceae, Aphanothecoideae Notes to taxonomy, misinterpretations:From 12 described species were 6 confirmed. The majority of species have their limited areas of distribution (in respect of their special ecology). The members with "small" (3-3.5 um) cells and the strains studied by Rippka and Cohen-Bazire (1983) belong probably to the genus Cyanobium or into a special genus |
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| Ecology, ecophysiology, ecological significance: Komárek (1992):In metaphyton of shallow pits, pools, moors, swamps and small lakes with plenty of water plants, rarely secondary in plankton; two (and probably more) species occur in salinic and hypersalinic swamps; few species grow subaerophytically on barks of trees wet rocks and in humid, several only in thermal spring. |
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| Physiology and biochemistry: |
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| Distribution, endemism, problematic citations: |
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| Infrageneric scheme, species concept: |
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| List of species: Cyanothece aeruginosa (Nägeli) Komárek 1976 Cyanothece epiphytica M. Watanabe et Komárek 1998 Cyanothece halobia Roussomoustakaki et Anagnostidis 1991 Cyanothece lineata Komárek et Komárková-Legnerová 2002 Cyanothece major (Schröter) Komárek 1976 Cyanothece shiloi (Campbell et Golubić) Komárek et Anagnostidis 1995 Unclear taxa: |
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Drawings: Komárek (1992) |
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Literature:
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