Anabaena variabilis

A shift in temperature from 38 to 22 °C leads to desaturation of fatty acids in Anabaena variabilis [110], resulting in control of the fluidity of the plasma membrane. Mutants have been isolated in Synechocystis PCC 6803 that were defective in desaturation of fatty acids, and the growth rate of one of these mutants was much lower than that of the wild-type at 22 °C [112]. It turned out that the mutant strain had a mutation in the gene desA, and when the wild-type allele was introduced into the chilling-sensitive cyanobacterium Anacystis nidulans, it resulted in increasing the tolerance of that strain to low temperature [113]. These experiments nicely demonstrate the existence of a mechanism of adaptation to low temperature in a chilling-tolerant cyanobacterium. 

The action spectmm of positive and negative phototaxis of Anabaena variabilis was measured recently106). This species contains no C-phycoerythrin. Accordingly, maximum activity is found at around 615 nm (Fig. 7). In addition, in this form a second maximum occurs at around 675 nm, and a third small, but distinct, one at 440 nm, both indicating that chlorophyll a is also involved in the active light absorption (see above). The utilization via photosynthesis, however, could be excluded in this case, since the trichomes oriented themselves perfectly well to the light direction in the presence of photosynthetic inhibitors, such as DCMU and DBMIB, at concentrations in which the photosynthetic oxygen evolution was almost completely inhibited. 

Fig. 7. Action spectrum of positive phototaxis (circles and solid line) and in vivo absorption spectrum (solid line) of Anabaena variabilis. Abscissa wavelength in nm Ordinates phototactic effect in relative units and absorbance respectively (after Nultsch et al.102))...

Source Porphyridium cruentum Gastroclonium coulter i Anabaena variabilis Anabaena variabilis... 

Kumar, H.D. and G. Prakash. 1971. Toxicity of selenium to the blue-green algae, Anacystis nidulans and Anabaena variabilis. Ann. Bot. 35 697-705. 

T. Happe, K. Schiitz, H. Bohm (2000) Transcriptional and mutational analysis of the uptake hydrogenase of the filamentous cyanobacterium Anabaena variabilis ATCC 29413.. /. Bacteriology, 182 1624-1631... 

T. Thiel (1993) Characterization of genes for an alternative nitrogenase in the cyanobacterium Anabaena variabilis. J. Bacteriol., 175 6276-6286... 

It is interesting to note that the plastocyanin from the alga Anabaena variabilis has a similar structure to that isolated from poplar, while having a different amino acid sequence.58 This results in an overall positive charge of +2. Thus, as shown in Figure 32a, it affords a wellshaped response for the Cu(II)/Cu(I) reduction E° = + 0.32 V vs. NHE) using a perpendicular pyrolytic graphite electrode, without the presence of additives. 

Figure 32 Cyclic voltammograms recorded at an edge-oriented pyrolitic graphite electrode in an aqueous solution (pH 7.0) of plastocyanin from Anabaena variabilis. In the absence (a) and in the presence (a) of Mg(II) salts. Scan rate 0.01 V s ...

Fig. 4. View of the blue copper and a5Rupis59) centers in ruthenated Anabaena variabilis plastocyanin. The edge-edge distance is 11.9 A [39]...

These enzymes are found in filamentous Cyanobacteria, e.g. Anabaena 7120 (Houchins and Burris 1981), Nostoc sp. strain PCC73102 (Oxelfelt et al. 1998) and Anabaena variabilis (Schmitz et al. 1995) where they occur in the heterocysts. They may also occur in vegetative Anabaena cells grown under microaerobic or anaerobic non-N2-fixing... 

Borodin, V. B., Tsygankov, A. A., Rao, K. K. and Hall, D. O. (2000) Hydrogen production by Anabaena variabilis PK84 under simulated outdoor conditions. Biotechnol. Bioeng., 69, 478-85. 

Kentemich, T., Danneberg, G., Hundeshagen, B. and Bothe, H. (1988) Evidence for the occurrence of the alternative, vanadium-containing nitrogenase in the cyanohacterium Anabaena variabilis. PEMS Microbiol. Lett., 51, 19-24. 

Serebryakova, E. T., Medina, M., Zorin, N. A., Gogotov, I. N. and Cammack, R. (1996) Reversible hydrogenase of Anabaena variabilis ATCC 29413 Catal) tic properties and characterization of redox centers. FEBS Lett., 383, 79-82. 

Spiller, H., Bookjans, G. and Shanmugam, K. T. (1983) Regulation of hydrogenase activity in vegetative cells oi Anabaena variabilis. J. BacterioL, 155, 129-37. 

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... 

Ogawa, T., Vernon, L.P. and Mollenhauer, H.H. 1969. Properties and structure of fractions prepared from Anabaena variabilis by the action of Triton X-100. Biochim. Biophys. Acta, 172.216-229. 

Boison, G., Bothe, H., and Schmitz, O. 2000. Transcriptional analysis of hydrogenase genes in the cyanobacteria Anacystis nidulans and Anabaena variabilis monitored by RT-PCR. Curr. Microbiol. 40 315-321. 

Thiel, T., and Pratte, B. 2001. Effect of heterocyst differentiation of nitrogen fixation in vegetative cells of the cyanobacterium Anabaena variabilis ATCC 29413. J. Bacteriol. 183, 280-286. 

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