fulltext.study @t Gmail

Effects of 60Co γ radiation on thylakoid membrane functions in Anacystis nidulans

Paper ID Volume ID Publish Year Pages File Format Full-Text
31141 44554 2008 11 PDF Available
Title
Effects of 60Co γ radiation on thylakoid membrane functions in Anacystis nidulans
Abstract

In photosynthetic organisms oxidative stress is known to result in photoinactivation of photosynthetic machinery. We investigated effects of 60Co γ radiation, which generates oxidative stress, on thylakoid structure and function in cyanobacteria. Cells of unicellular, non-nitrogen fixing cyanobacterium Anacystis nidulans (Synechococcus sp.) showed D10 value of 257 Gy of 60Co γ radiation. When measured immediately after exposure, cells irradiated with 1500 Gy (lethal dose) of 60Co γ radiation did not show any differences in photosynthetic functions such as CO2 fixation, O2 evolution and partial reactions of photosynthetic electron transport in comparison to unirradiated cells. Incubation of irradiated cells for 24 h in light or dark resulted in decline in photosynthesis. The decline in photosynthesis was higher in the cells incubated in light as compared to the cells incubated in dark. Among the partial reactions of electron transport, only PSII activity declined drastically after incubation of irradiated samples. This was also supported by the analysis of membrane functions using thermoluminescence. Exposure of cyanobacteria to high doses of 60Co γ radiation did not affect the thylakoid membrane ultrastructure immediately after exposure as shown by electron microscopy. The level of reactive oxygen species (ROS) in irradiated cells was 20 times higher as compared to control. In irradiated cells de novo protein synthesis was reduced considerably immediately after irradiation. Treatment of cells with tetracycline also affected photosynthesis as in irradiated cells. The results showed that photoinhibition of photosynthetic apparatus after incubation of irradiated cells was probably augmented due to reduced protein synthesis. Active photosynthesis is known to require uninterrupted replenishment of some of the proteins involved in electron transport chain. The defective thylakoid membrane biogenesis may be leading to photosynthetic decline post-irradiation.

Keywords
Cyanobacteria; 60Co γ radiation; Lethal dose; Photosynthesis; Thylakoid membrane
First Page Preview
Effects of 60Co γ radiation on thylakoid membrane functions in Anacystis nidulans
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 91, Issue 1, 25 April 2008, Pages 9–19
Authors
, , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us