PhD Defense | Anu Yadav | Mechanisms of ionizing radiation resistance in Arthrospira sp. PCC 8005 | UHasselt

Mechanisms of ionizing radiation resistance in Arthrospira sp. PCC 8005 

The multicellular cyanobacterium Arthrospira has been studied for many years because of its excellent nutritive value as a food- and feedstock and its many applications in biomedical sciences. Arthrospira sp. PCC 8005 (now known as Limnospira indica PCC 8005) is a principal organism and edible end product of the MELiSSA bioreactor, a life support system being developed by an ESA-funded international consortium, with SCK CEN as a research partner. This organism is highly radioresistant, i.e., surviving upto 5000 Gy of ⁶⁰Co gamma radiation, yet the mechanisms for this resistance remain elusive.

In this study, we investigated the radiation resistance mechanisms of strain PCC 8005 and the differences between the helical form (designated P6) and a new linear form (designated P2) found in the lab during continuous culturing, when subjected to acute gamma exposure at a dose rate of 600 Gy.h^-1. We obtained the full genome sequences for the P2 and P6 strains allowing comparative analysis with the genome of the Arthrospira sp. PCC 8005 parental strain as reference. These two morphotypes P2/P6 were also subjected to chronic gamma radiation at a dose rate of ca. 80 Gy.h^-1 for one lifecycle under continuous light and were analyzed for differential gene expression using RNAseq analysis. Five genes of the arh locus,of unknown function but highly expressed in response to gamma irradiation, were cloned and heterologously expressed in E. coli for further study.

Promotors:

• Ann Cuypers (UHasselt)

SCK CEN mentors:

• Paul Janssen (SCK CEN)

• Natalie Leys (SCK CEN)

Click here for a list of obtained PhD degrees.