Superoxide Dismutase in the Symbiont <i>Anabaena azollae</i> Strasb.

Canini, Antonella; Galiazzo, Francesca; Rotilio, G.; Caiola, M. Grilli

doi:10.1104/pp.97.1.34

Cited by 14 publications

(9 citation statements)

References 29 publications

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“…For all samples from the Baltic Sea, the density of gold particles was low compared with that measured in Azolla (Canini et al, 1991) and cycad cyanobionts (Grilli Caiola & Canini, 1994), but similar to that found in Anabaena cylindrica grown at low incident irradiance (Grilli Caiola & Canini, 1993). Our data show a clear correlation between irradiance and areal Fe-SOD concentrations and confirm the earlier findings of Canini et al (1996) that the heterocysts of trichomes of Nodularia spp.…”

Section: -50 % Of the Values For ' Scum ' Samples (Figs 2-4)supporting

confidence: 90%

Localization of Fe‐containing superoxide dismutase in cyanobacteria from the Baltic Sea: depth and light dependency

1998

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The abundance and cellular location of Fe-containing superoxide dismutase (Fe-SOD) in trichomes of Nodularia, Aphanizomenon and Anabaena collected from various depths in the Baltic Sea, and in trichomes of a cultured Nodularia strain, BC Nod-9427, isolated from the Baltic Sea, was examined by immunogold labelling. For trichomes collected from natural populations the areal concentration of Fe-SOD labelling decreased with depth : trichomes collected from surface accumulations had between 8 and 11 gold particles µm −# whereas trichomes collected from a depth of 18 m were unlabelled. When trichomes collected from a depth of 10 m (mean areal labelling density 0n5 gold particles µm −# ) were exposed to the higher irradiances present at 1 m, the areal concentration of Fe-SOD increased to 3n5-4 gold particles µm −# within 4 h. When cultures of Nodularia strain BC Nod-9427, adapted to low light (10 µmol m −# s −" ), were transferred to an incident irradiance of 1350 µmol m −# s −" , a doubling of the areal concentration of Fe-SOD gold label was observed within 1 h. Addition of 3-(3,4-dichlorophenyl)-1,1h-dimethylurea (DCMU) to cultures immediately before their transfer to increased illumination resulted in a decrease in areal Fe-SOD concentrations whereas addition of CdCl # caused an increase over and above that induced by the elevated irradiance. These results suggest that Baltic Sea cyanobacteria are able to modulate their Fe-SOD content but that this might be in response to oxidative stress rather than to light per se.

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Section: -50 % Of the Values For ' Scum ' Samples (Figs 2-4)supporting

confidence: 90%

Localization of Fe‐containing superoxide dismutase in cyanobacteria from the Baltic Sea: depth and light dependency

1998

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“…However, given that this protective effect lasted only briefly, we were unable to establish whether cell degeneration was a consequence of decreased Fe‐SOD activity or whether the decreased Fe‐SOD activity was a consequence of cell degeneration. Although increased Fe‐SOD activity has been observed in relation to increased irradiance in A. cylindrica (Grilli Caiola & Canini, 1993), A. azollae (Canini et al. , 1991) and Nodularia sp.…”

Section: Discussionmentioning

confidence: 99%

“…, 1996). In many cyanobacteria, the greatest proportion of SOD activity in cells is due to Fe‐SOD, whose concentration has been shown to increase when cyanobacteria are transferred from low to high levels of photosynthetically active radiation (Canini et al. , 1991; Grilli Caiola & Canini, 1993).…”

Section: Introductionmentioning

confidence: 99%

Superoxide dismutase activity in the cyanobacterium Microcystis aeruginosa after surface bloom formation

2001

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Summary• The presence of superoxide dismutase (SOD) enzymes and the response of SOD after in vitro induction and decay of a surface bloom are shown in cultures of the cyanobacterium Microcystis aeruginosa .• The SOD enzymes of surface blooms, early degenerate and completely degenerate cultures were assayed by staining for SOD activity, immunoblotting and immunogold labelling.• One band of Mn-and three bands of Fe-SOD were detected in cell extracts. During surface bloom formation, Fe-SOD activity increased fivefold compared with that in control cells; no variation was detected in Mn-SOD activity. However, in early degenerate cultures, Fe-SOD activity decreased to that seen in control cultures, while activity disappeared in completely degenerate cultures. Immunogold labelling showed that Fe-SOD was localized in the cytoplasmic and thylakoid membranes of Microcystis . The extent of labelling paralleled the course of Fe-SOD activity with an increase in particles in surface blooming cells.• The results suggest Fe-SOD increased due to photooxidative stress. However, under prolonged photooxidative stress, high concentrations of active oxygen species could directly, or indirectly, inactivate and degrade Fe-SOD.

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“…Canini et al . 20 proposed that cyanophycin serves as a plug that closes the neck of the heterocyst connection to the vegetative cell. However, until now hardly anything is known about the physical properties of this insoluble polymer and it is therefore unknown whether this material is gas tight.…”

Section: Discussionmentioning

confidence: 99%

The effect of oxygen concentration and temperature on nitrogenase activity in the heterocystous cyanobacterium Fischerella sp.

Stal

2017

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Heterocysts are differentiated cells formed by some filamentous, diazotrophic (dinitrogen-fixing) cyanobacteria. The heterocyst is the site of dinitrogen fixation providing the oxygen-sensitive nitrogenase with a low-oxygen environment. The diffusion of air into the heterocyst is a compromise between the maximum influx of dinitrogen gas while oxygen is kept sufficiently low to allow nitrogenase activity. This investigation tested the hypothesis that the heterocyst is capable of controlling the influx of air. Here, the thermophilic heterocystous cyanobacterium Fischerella sp. was analysed for the effects of oxygen concentration and temperature on nitrogenase activity. Dark nitrogenase activity is directly related to aerobic respiration and was therefore used as a measure of the influx of oxygen into the heterocyst. Above 30% O2, the influx of oxygen was proportional to its external concentration. Below this concentration, the influx of oxygen was higher than expected from the external concentration. A higher or lower temperature also triggered the heterocyst to increase or decrease, respectively, dark nitrogenase activity while the external concentration of oxygen was kept constant. A higher dark nitrogenase activity requires a higher rate of respiration and therefore a higher flux of oxygen. Hence, the heterocyst of Fischerella sp. is capable of controlling the influx of air.

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Superoxide Dismutase in the Symbiont Anabaena azollae Strasb.

Cited by 14 publications

References 29 publications

Localization of Fe‐containing superoxide dismutase in cyanobacteria from the Baltic Sea: depth and light dependency

Localization of Fe‐containing superoxide dismutase in cyanobacteria from the Baltic Sea: depth and light dependency

Superoxide dismutase activity in the cyanobacterium Microcystis aeruginosa after surface bloom formation

The effect of oxygen concentration and temperature on nitrogenase activity in the heterocystous cyanobacterium Fischerella sp.

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