title: The high-energy radiation protectant extracellular sheath pigment scytonemin and its reduced counterpart in the cyanobacterium Scytonema sp. R77DM.
abstract: A cyanobacterial extracellular sheath pigment from Scytonema sp. R77DM was partially characterized and investigated for its increased production under abiotic factors, and UV-screening function. HPLC with PDA detection, and ion trap liquid chromatography/mass spectrometry analysis revealed the presence of a pigment scytonemin and its reduced counterpart. Ultraviolet radiation showed more stimulative effects on scytonemin production. A significant synergistic enhancement of scytonemin synthesis was observed under combined stress of heat and UV radiation. Scytonemin also exhibited efficient UV-screening function by reducing the in vivo production of reactive oxygen species (ROS) and cyclobutane thymine dimer. UV-induced formation of ROS and thymine dimer was also reduced upon exposure of cyanobacterial cells to exogenous antioxidant, ascorbic acid; however, the effect was more significant when both scytonemin and ascorbic acid were applied in combination. Moreover, the results indicate the potential role of scytonemin pigment as natural photoprotectant against high energy solar insolation.
authors.affiliation: BRD School of Biosciences, Sardar Patel Maidan, Vadtal Road, Satellite Campus, Post Box No. 39, Sardar Patel University, Vallabh Vidyanagar 388 120, Anand, Gujarat, India. Electronic address: raj_rastogi@rediffmail.com.
authors.forename: Rajesh P
authors.initials: RP
authors.lastname: Rastogi
authors.affiliation: BRD School of Biosciences, Sardar Patel Maidan, Vadtal Road, Satellite Campus, Post Box No. 39, Sardar Patel University, Vallabh Vidyanagar 388 120, Anand, Gujarat, India. Electronic address: ravi123sonani@gmail.com.
authors.forename: Ravi R
authors.initials: RR
authors.lastname: Sonani
authors.affiliation: BRD School of Biosciences, Sardar Patel Maidan, Vadtal Road, Satellite Campus, Post Box No. 39, Sardar Patel University, Vallabh Vidyanagar 388 120, Anand, Gujarat, India. Electronic address: datta_madamwar@yahoo.com.
authors.forename: Datta
authors.initials: D
authors.lastname: Madamwar
mesh_terms: D000704:Analysis of Variance; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D000458:Cyanobacteria / Q000737:chemistry* / Q000528:radiation effects; D006358:Hot Temperature; D007211:Indoles / Q000032:analysis / Q000378:metabolism*; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis / Q000378:metabolism*; D010860:Pigments, Biological / Q000032:analysis / Q000096:biosynthesis*; D011740:Pyrimidine Dimers / Q000378:metabolism; D011837:Radiation-Protective Agents / Q000032:analysis / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013312:Stress, Physiological / Q000502:physiology* / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D007211:Indoles; D010636:Phenols; D010860:Pigments, Biological; D011740:Pyrimidine Dimers; D011837:Radiation-Protective Agents; D017382:Reactive Oxygen Species; C083368:scytonemin
keywords: Cosmeceutical; Cyanobacteria; Induction; Photoprotection; Scytonemin pigment