Effect of UV-B radiation on amino acids profile, antioxidant enzymes and lipid peroxidation of some cyanobacteria and green algae

Abstract

Background

UV radiation and its impact on living organisms became an essential concern over the past three decades and will be essential in the years to come. So, the present investigation was devoted to examining the impact of artificial UV-B radiation on the accumulation of amino acids and MDA contents as well as some antioxidant enzymes activities in three freshwater cyanobacterial species; Planktothrix cryptovaginata, Nostoc carneum and Microcystis aeruginosa, one freshwater green alga; Scenedesmus acutus and one marine cyanobacterium; Microcystis.

Methods

The algal cultures were exposed directly to artificial UV-B radiation for 1, 3, 5, and 7 hours and amino acids, MDA contents, and the antioxidant enzyme activities; CAT, POD, APX, and SOD were analyzed.

Results

The data obtained indicated that alteration in MDA and antioxidant enzymes by UV stress depends on the algal species and the exposure time. The treatment of the investigated algae with different periods of UV-B exposure stimulated the biosynthesis of some individual amino acids and inhibited the accumulation of some others. In some cases, exposure to UV-B was accompanied by the disappearance of some amino acids. In addition, UV-B exposure for 3 hours stimulated the accumulation of total amino acids in M. aeruginosa and S. acutus, while 7 hours of UV-B enhanced the biosynthesis of total amino acids in M. aeruginosa only from the investigated algae.

Conclusion

Exposure of some cyanobacteria and green algae to UV-B radiation stimulated the biosynthesis of some individual amino acids and inhibited the accumulation or accompanied by the disappearance of some others. However, the alteration in MDA and antioxidant enzymes by UV stress depends on the algal species and the exposure time.

Keywords:

• Antioxidant enzymes
• amino acids
• chlorophyta
• cyanobacteria
• MDA
• UV-B radiation

Acknowledgments

The authors would like to thank Prof. Dr. Wesam Salem, Faculty of Science, South Valley University for his valuable help in statistical analysis of the data.

Disclosure statement

The authors declare no conflict of interest and are alone responsible for the content and writing of the paper.

Additional information

Notes on contributors

Hani Saber

Hani Saber is a Lecturer of Phycology at South Valley University and he is working on the effect of UV radiation on the growth and metabolism of algae and cyanobacteria.

Mostafa M. El-Sheekh

Mostafa El-Sheekh is Professor of Phycology application at Tanta University. He has published and worked extensively on applications of UV and supervised many theses on the impact of UV on Microrganisms.

Aml Ibrahim

Aml Ibrahim is a Master’s student studying radiation application at South Valley University.

Eman A. Alwaleed

Eman A. Alwaleed is a Lecturer of Phycology at South Valley University and he is working on the effect of UV radiation on the growth and metabolism of algae and cyanobacteria.