Differential response of growth, photosynthesis, antioxidant enzymes and lipid peroxidation to UV-B radiation in three cyanobacteria

Differential Response to Moderate UV-B Irradiation of Two Heterocystous Cyanobacteria Isolated from a Temperate Ricefield

“…BI42, after 3 hours of exposure showed a significant increase of lipid membrane damage measured as TBARS ( Table 1). This provides indirect evidence of increased photoxidative damage stress by ROS after UV-B exposure in this cyanobacterium as has been reported before [27,46]. There was no significant change in lipid peroxidation in Calothrix sp.…”

“…High activity of these enzymes in cyanobacteria could be linked to stress tolerance efficiency [46].…”

The combined effects of UV-B radiation and herbicides on photosynthesis, antioxidant enzymes and DNA damage in two bloom-forming cyanobacteria

“…This was attributed to the most active non-enzymatic antioxidants, ASC, which directly scavenged O2 À , OH and reduced H 2 O 2 to water via ascorbate peroxidase to provide powerful protection for membranes under stress conditions (Noctor and Foyer, 1998;Smirnoff, 2011). Increased UV-B radiation affects the normal metabolism in all organisms Zeeshan and Prasad, 2009). …”

“…These increased ROS can easily destroy proteins, DNA and other biological molecules, and subsequently affect growth and reproduction, survival, photosynthetic energy harvesting enzymes, and the content of photosynthetic pigments (Wang and Zhang, 2001;Apel and Hirt, 2004;Holzinger and Lütz, 2006). UV radiation can also alter species composition, and the vertical distribution and metabolism of aquatic ecosystems, which causes shifts in phytoplankton community structure and the food web (Häder et al, 1995;Häder, 2000;Zeeshan and Prasad, 2009). However, cyanobacteria have also developed adaptation strategies to counteract the damaging effects of UV irradiance, which include avoidance, scavenging, screening, repair and programmed cell death (Quesada and Vincent, 1997;Sinha et al, 1998;Sinha and Häder, 2008;Singh et al, 2010).…”

Damage to DNA caused by UV-B radiation in the desert cyanobacterium Scytonema javanicum and the effects of exogenous chemicals on the process

“…In low doses, the radiation influences metabolism and growth in many organisms, particularly in photo-autotrophs, which need light as a source of energy to synthesize biomass (Holzinger and Lütz, 2006;Zeeshan and Prasad, 2009). However, evidence that UV-B radiation causes cell damage in all forms of life continues to grow.…”