What is Cynobacteria

Cynobacteria,formerly  known as  blue - green algae, are evolved at least 2.5 billion years ago, which is roughly 1 billion years before the first eukaryotes. Cynobacteria are the largest and most diverse group of photosynthetic prokaryotes. Their great variety of size, shapes and metabolic activities allows them to thrive in many environments; in thermal hot springs where temperature can be over 80°C; in the snow of high mountains in marine and fresh waters; in soils; even on otherwise lifeless volcanic rocks.


Cynobacteria is a plant or bacteria?

The taxonomic treatment, primarily based on their plant like photosynthetic activities, became untenable around 1960 when fundamental differences in cellular organisation of prokaryotes and eukaryotes were fully elucidated. 

It is now clear that while cyanobacteria and plants have many common features, they are really very different. While plants are eukaryotes, cynobCynobac are prokaryotes like other minerals. While both Cynobacteria and plant have cell wall, the plant wall is made up of cellulose, while the bacterial wall of peptidoglycan. A major difference from plants is that many forms of Cynobacteria can fix atmospheric nitrogen.

Similarities between Cynobacteria and Bacteria

Cohn (1853) first recognise the affinities between blue green algae and bacteria and placed them under a single division Schizophyta. Later Copeland (1936) classified the blue green algae and bacteria under Monera.

Some similarities between Cynobacteria and Bacteria are as follows:-
  • Nucleus has no membrane and not well organised
  • Thylakoids are present but these are not membrane bound as in eukaryotes.
  • Plastids are absent.
  • There is no gamete formation, fusion or meiosis.
  • Genetic recombination is reported in both.
  • Diaminopimilic acid is found in the cell wall.
  • Mucilage sheath is preasent in both.

Vegetative structure of Cynobacteria

Cynobacteria are unicellular, colonial or form chains of cell known as trichomes . In colonial forms all cells of a colony occur in a common gelatinous matrix. In some Cynobacteria, specialised structure, known as heterocysts, are present. They may be terminal or intercalary in position. They are supposed to be the Nitrogen fixation. They show gliding or jerky movements; flagella being altogether absent.

Reproduction in a Cynobacteria

Reproduction takes place by vegetative and asexual methods. Sex organs, gametes and flagellated zoospores are altogether absent.
However in some Cynobacteria genetic recombination has been reported. Vegetative reproduction takes place usually by cell division and fragmentation, whereas asexual reproduction is by akinetes, endospores and heterocysts.

Economic Importance Of Cynobacteria

Nostoc commune

CyniCynobact are economically important. Spirulina, a non toxic, fast growing Cynobacteria is cultured in tanks as a protein rich food. 
Nostoc commune is eaten as food in China and Java. Synchrococcus serves food in space flights and nuclear membrane. It is also water recycling and oxygen regenerating organism.

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