Clinical Microbiology: Open Access

Identification and characterization of the origin of replication of the multiple chromosomes in Rhodobacter sphaeroides

3^rd Global Microbiologists Annual Meeting

August 15-17, 2016 Portland, Oregon, USA

Madhusudan Choudhary

Sam Houston State University, USA

Posters & Accepted Abstracts: Clin Microbiol

Abstract:

Rhodobacter sphaeroides is a facultative anaerobic bacterium which belongs to the α-3 subdivision of Proteobacteria. It has a complex genome, consisting of two chromosomes, chromosome I (CI) and chromosome II (CII), which are approximately 3 Mb and 0.9 Mb, respectively. The objective of this study was to identify and characterize the origins of replication of the two chromosomes and analyze them with respect to chromosomal or plasmid origin type. Using bioinformatics approaches, such as Z-curve and GC-skew analyses, three and five putative chromosomal origin regions were identified on CI and CII, respectively. The flanking regions of these putative regions were analyzed for the conservation of genes known to be located near confirmed replicative origins of other bacterial species. Each of the putative regions were amplified and cloned into a pLO1 vector, which contains a Kanamycin resistance gene and acts as a suicide vector in R. sphaeroides. These recombinant pLO1 plasmids were mobilized into R. sphaeroides using biparental mating of E. coli S17-1 and R. sphaeroides. Resulting transconjugants were characterized for the autonomous replication of the plasmid in R. sphaeroides. Conservation of genes proximal to the replication origins as well as biological characterization of these putative origin sequences confirmed the respective origins of the two chromosomes. Results also revealed that the replicative origin of the primary chromosome is a typical bacterial chromosomal type, while secondary chromosome is located near parA and parB genes, an arrangement shared by a number of megaplasmids in other bacteria.

Biography :

Email: mxc017@SHSU.EDU