Isolation and in silico analysis of antioxidants in response to temporal variations in the cyanobacterium Oscillatoria sp.

Abstract

Abstract The present study aims to investigate the responses of certain antioxidants and photosynthetic pigments to temporal variations during winter, summer and rainy seasons in the cyanobacterium Oscillatoria sp. inhabiting sewage water. Native-PAGE enzyme profile of superoxide dismutase (SOD) explicated that while isoform number 1 identified as Mn-SOD was observed solely during rainy season, isoform number 2 identified as Fe-SOD was present persistently in all the three seasons. However, densitometry analyses illustrated intra-specific seasonal variations depicting Fe-SOD isoform intensity being highest in summer season followed by rainy and winter seasons respectively. Native-PAGE enzyme profile elucidated the presence of four isoforms of catalase enzyme during summer season followed by three isoforms during winter and single isoform during summer seasons. Correlation matrix revealed that except phycocyanin which shows negative correlation with allophycocyanin, all other polar and non-polar solvent soluble photosynthetic pigments reveal positive correlation among themselves in response to temporal variations. 3D models of Fe-SOD and Mn-SOD in Oscillatoria sp. generated by homology modeling were validated to be of good quality. High conservation of all metal binding positions was also observed. The phylogenetic tree revealed that Planktothricoides sp. SR001 and Phormidiumam biguum were closest evolutionary homolog of Fe-SOD and Mn-SOD respectively in Oscillaroria sp. Thus, enzymatic and non-enzymatic antioxidants contribute jointly and specifically to combat oxidative stress thereby serving as biomarker of the response to various unfavorable temporal environmental cues prevailing at the natural habitat of Oscillatoria sp. The cyanobacterial antioxidative potential may be a crucial sustainable resource for several industrial processes exploiting biochemical and biotechnological applications.