GENERAL MICROBIOLOGY - T.P. Pyrog - 2004

18. PHOTOTROPHIC BACTERIA AND PHOTOSYNTHESIS

18.2. CYANOBACTERIA

Based on morphological characteristics, they are divided into five groups (Table 18.2).

Class="center">Table 18.2.

Characteristics of Cyanobacteria

Groups

Characteristics

Representatives

1. Chroococcalean cyanobacteria

Unicellular rods and cocci, occurring singly or in aggregates held together by capsules or mucilage. Reproduction occurs by binary fission or budding.

Genera Synechococcus, Gloeobacter, etc.

2. Pleurocapsalean cyanobacteria

Also unicellular forms, but capable of reproducing by multiple fission. In this process, numerous small Cells—baeocytes—are formed within the dividing mother Cell.

Genera Pleurocapsa, Dermocarpella, Myxosarcina, etc.

3. Filamentous cyanobacteria lacking heterocysts

Trichomes consist exclusively of vegetative cells.

Genera Oscillatoria, Spirulina, Plectonema, etc.

4. Filamentous cyanobacteria

with heterocysts

In addition to heterocysts, they can form akinetes—resting cells that differentiate from a vegetative cell by developing a thick outer wall, increasing in volume, and accumulating cyanophycin, Glycogen, Lipids, and carotenoids. Cells divide in a single

plane.

Genera Anabaena, Nostoc, etc.

5. Filamentous cyanobacteria with heterocysts

Differ from group 4 in that the cells divide in more than one plane.

Genus Fischerella


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