Bioinformatic Analyses of Chromium Tolerant Genes in Cyanobacteria and Identification of Chromium Tolerant Operon in Synechococcus sp. IU 625

摘要

Heavy metal contamination in the environment is always a big concern. Many microorganisms have developed metal tolerant/resistant mechanisms to survive in such environment. Cyanobacterium Synechococcus sp. IU 625 (S. IU 625) has been used an indicator for studying many EPA targeted heavy metals such as Zn(2+), Cu(2+), Hg(2+). This microorganism has been reported to have resistant mechanisms to mercury and zinc. In this study, bioinformatics tools were used to determine the plasmid-mediated chromium resistant genes of S. IU 625. An operon involved in chromium resistance has been proposed. For each gene within the proposed operon, PCR primers were designed to amplify the plasmid DNA of S. IU 625. The complete sequence of the operon has been obtained. Homology search suggested that this operon has high homology to Synechococcus elongatus PCC 7942. The phylogenic analysis of the chromate transporters has shown some distance among cyanobacteria.