An extensive comparative genome analysis of oligonucleotide (OU), codon and aminoacid usage patterns will be undertaken within the genus Arthrospira in reference to other prokaryote genomes. These composition-based approaches will help us to unravel the adaptive strategies employed by Arthrospira to survive extreme high doses of radiation.
In addition, for a wide range of prokaryotes adapted to ionising radiation (IR), a full catalogue of genes involved in all aspects of radioresistance will be made including genes that are, according to literature, involved in ROS-avoidance and –detoxification, general antioxidant functions, metal ion homeostasis, oxygen transport, redox sensing, cell wall synthesis, cell division, SOS-response, and DNA-repair. Any other cellular processes reportedly affected by IR will be investigated. Based on this catalogue (which would entail building a database of protein sequences for all selected genes) a search will be undertaken for Arthrospira orthologs by performing a BLASTp operation of this database against the eight Arthrospira proteomes known sofar (Arthrospira platensis YZ, C1, and NIES-39, Arthrospira sp. TJSD091, Arthrospira maxima CS328, and three subtypes of strain PCC 8005). In parallel, protein sequences corresponding to IR-affected PCC 8005 genes (fold change between 2 and 0.5) will be collected to form a protein sequence set that will be compared (by BLASTp) to the proteomes from a range of IR-sensitive and IR-resistant organisms. It is expected that these bioinformatic analyses will give first clues on the distribution of particular genes and their products across multiple organisms and may result in a broad correlation between the presence and absence of certain genes, or the differential expression of certain genes, in respect to IR-resistant and IR–sensitive phenotypes. In this way we also hope to identify protein signatures that allow the reliant discrimination between IR-sensitive and –resistant bacteria.