Cumulative Effects of Ultraviolet Radiation and Photosyntheically Active Radiation on Phycobiliproteins of A Hot-Spring Cyanobacatrium Nostoc sp. strain HKAR-2

Adinath Adinath,Rajneesh Rajneesh,Akhlaqur Rahman,Arun S Sonker,Jainendra Pathak,Rajeshwar P Sinha,Shanthy Sundaram,Vinod K Kannaujiya

doi:10.3126/ijasbt.v4i3.15595

Abstract

Cyanobacteria are cosmopolitan in distribution and have adapted to diverse habitats. Adaptation of cyanobacteria is one of the key factors to withstand harsh environmental conditions. We have investigated the effects of photosynthetically active radiation (PAR; 400–700 nm), ultraviolet-B (UV-B; 280–315 nm) radiation and PAR+UV-B radiations on phycobiliproteins (PBPs) of a hot-spring cyanobacterium Nostoc sp. HKAR-2. There was a continuous induction of both phycoerythrin (PE) and phycocyanin (PC) after exposure of PAR up to 300 min. However, there was an induction in the synthesis of both PE and PC up to 240 min exposure of UV-B and PAR+UV-B radiations. Further exposure showed decline in the synthesis due to rapid uncoupling, bleaching and degradation of PBPs. Similarly, emission fluorescence also showed an induction with a shift towards longer wavelengths after 240 min of UV-B and PAR+UV-B exposure. These results indicate that short duration of UV radiation may promote the synthesis of PBPs that can be utilized in various biotechnological and biomedical applications. Int J Appl Sci Biotechnol, Vol 4(3): 247-253

Highlights

Cyanobacteria are the most ancient and dominant group of Gram-negative photosynthetic prokaryotes having cosmopolitan distribution from moderate to extreme habitats (Fischer, 2008; Ballaré et al, 2011)
Solar spectrum is physically divided into three major groups such as infrared (IR; 780 nm), photosynthetically active radiation (PAR; 400–700 nm), and ultraviolet radiation (UVR; 100–400 nm) that reaches on the Earth’s surface
The aim of present investigation was to study the cumulative effects of UV-B and PAR irradiations on PBPs composition of a hot-spring cyanobacterium Nostoc sp. strain HKAR-2

Summary

Introduction

Cyanobacteria are the most ancient and dominant group of Gram-negative photosynthetic prokaryotes having cosmopolitan distribution from moderate to extreme habitats (Fischer, 2008; Ballaré et al, 2011). Solar spectrum is physically divided into three major groups such as infrared (IR; 780 nm), photosynthetically active radiation (PAR; 400–700 nm), and ultraviolet radiation (UVR; 100–400 nm) that reaches on the Earth’s surface. About 5% UV-B radiation which is not completely absorbed by stratospheric ozone layer reaches to the Earth’s surface and is harmful to all living organisms (Polo et al, 2014). Kannaujiya et al (2016) Int J Appl Sci Biotechnol, Vol 4(3): 247-253 cyanobacteria It has been characterized into three groups such as phycoerythrin (PE), phycocyanin (PC) and allophycocyanin (APC) with absorbance ranging from 450 to 660 nm (Grossman et al, 1993; Sinha and Häder, 2003). PBSs are arranged in trimeric-hexameric macromolecular assembly (3-7M Da) with colorless linker polypeptides in six to eight rods and a core having two to five cylinders (Adir, 2008) (Fig. 1A, B, C)

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Materials and Methods

Results and Discussion

Conclusion