Cyanobacteria carbon dioxide fixation

They are not especially abundant in vivo. They exhibit less than 30% sequence identity to other thioredoxins although the overall tertiary structure may be conserved. They cannot be reduced by NADPH which suggests that the ferredoxin-dependent system (11) is the primary source of electrons. The evidence indicates that these thioredoxins have functions which are unique to photosynthetic organisms such as activation of enzymes in the carbon dioxide fixation cycle. Since the primary structures of these two thioredoxins do not appear to be similar, it may be that the cyanobacterial thioredoxin has diverged and may also have functions unique to cyanobacteria. 

Gantt E., Lipschultz C.A. Zilinskas B.A. (1977) Phycobilisomes in relation to the thylakoid membranes, Brookhaven Symp. Biol. 28, 357-357. Joset-Espardellier-F., Astier C., Evans E.H. and Carr, N.G. (1978) Cyanobacteria grown under Photoautotrophic, Photoheterotrophic and Heterotrophic regimes sugar metabolism and carbon dioxide fixation,... 

The photoheterotrophic microorganisms are represented by cyanobacteria such as Nostoc sp. and Anabaena variabilis. They are capable of photosynthesis using sunlight and carbon dioxide in a similar manner as the photoautotrophs. They are also capable of nitrogen fixation mediated by a nitrogenase enzyme, and this is where the carbon is needed, according to the formula... 

The lithoautotrophs have to form cellular materials from carbon dioxide. The process to change carbon dioxide into organic compounds is called fixation of carbon dioxide. On the basis of the knowledge to date, all algae and cyanobacteria, and many of the plants, fix carbon dioxide through the Calvin-Benson cycle (or reductive pentose phosphate cycle) (Bassham et al., 1954), while the plants of 20 families and 1200 species have been known to fix carbon dioxide through the Hatch-Slack pathway (or C4 dicarboxylate pathway) (Hatch et al., 1967). 

The oxidized forms of carbon available for photosynthesis are the carbon dioxide in the atmosphere and the soluble bicarbonate and carbonate in the waters of the earth s surface. On land, seed plants are the principal agents of photosynthesis accompanied by a minor contribution by the algae and cyanobacteria. In the oceans, the unicellular photosynthetic algae play the most important role in photosynthesis. It has been estimated that the total animal fixation of carbon in the oceans amounts to approximately 1.2 x 10 tons, whereas that on the land is about 1.6 x 10 tons [11]. 

Carbon dioxide assimilation, carbon fixation the incorporation of COj into larger organic compounds. C.d.a. is sometimes used as a synonym for photosynthesis, but strictly speaking photosynthesis is a series of reactions that generate the ATP and NAD(P)H required to drive the reactions of Cd.a. By far the greatest amount of C. d. a. occurs in green plants and cyanobacteria. Most of this occurs in the... 

---