Arsenic resistance of selected bacteria. (A) Genetic organization of arsenic resistance gene clusters compiled from the completed genome sequences of Bifidobacterium longun DJO10A, Bacillus subtilis 168 , Bacteroides thetaiotamicron VPI-5482 , Lactobacillus brevis ATCC 367 , L. plantarum WCFS1 , L. johnsonii NCC 533  and E. coli K-12 . a, 48 kb element that is excised by the site-specific recombinase SpoIVCA during sporulation, b, indicates a plasmid sequence, arsR, repressor, arsA, arsenite stimulated ATPase, arsB, arsenite efflux pump, arsC, arsenate reductase, arsD, arsenic chaperone, hyp, hypothetical protein. (B) Comparison of arsenic resistance activity in B. longum DJO10A with fermentation adapted B. animalis subsp. lactis strains, E. coli and Lactobacillus plantarum. c, calculated from data presented in van Kranenburg et al., .