title: Cyanobacteria and ultraviolet radiation (UVR) stress: mitigation strategies.
abstract: Cyanobacteria are primitive photosynthetic oxygen-evolving prokaryotes that appeared on the Earth when there was no ozone layer to protect them from damaging ultraviolet radiation (UVR). UVR has both direct and indirect effects on the cyanobacteria due to absorption by biomolecules and UVR-induced oxidative stress, respectively. However, these organisms have developed several lines of mitigation strategies/defense mechanisms such as avoidance, scavenging, screening, repair and programmed cell death to counteract the damaging effects of UVR. This review presents an update on the effects of UVR on cyanobacteria and the defense mechanisms employed by these prokaryotes to withstand UVR stress. In addition, recent developments in the field of molecular biology of UV-absorbing compounds such as mycosporine-like amino acids and scytonemin, are also added and the possible role of programmed cell death, signal perception as well their transduction under UVR stress is being discussed.
authors.affiliation: Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, D-91058 Erlangen, Germany.
authors.forename: Shailendra P
authors.initials: SP
authors.lastname: Singh
authors.forename: Donat-P
authors.initials: DP
authors.lastname: Häder
authors.forename: Rajeshwar P
authors.initials: RP
authors.lastname: Sinha
mesh_terms: D000596:Amino Acids / Q000378:metabolism / Q000528:radiation effects; D017209:Apoptosis / Q000502:physiology / Q000528:radiation effects; D002470:Cell Survival / Q000502:physiology / Q000528:radiation effects; D000458:Cyanobacteria / Q000502:physiology / Q000528:radiation effects*; D007211:Indoles / Q000378:metabolism / Q000528:radiation effects; D018384:Oxidative Stress / Q000502:physiology / Q000528:radiation effects*; D010636:Phenols / Q000378:metabolism / Q000528:radiation effects; D015398:Signal Transduction / Q000502:physiology / Q000528:radiation effects; D013312:Stress, Physiological / Q000502:physiology / Q000528:radiation effects*; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D000596:Amino Acids; D007211:Indoles; D010636:Phenols; C083368:scytonemin