Design a cadA-targeted DNA probe for screening of potential bacterial cadmium biosorbents

Due to their metal removal ability, bacterial biosorbents can be effectively used for the treatment of wastewaters containing heavy metals. Searching for bacterial biosorbents for hazardous heavy metals like cadmium is a pivotal for remediation efforts. The gene cadA, that mediates resistance to cadmium over an ATP-dependent efflux mechanism, provides a good target for the selection of potential cadmium biosorbents. For this reason, in this study, a 36-mer-oligonucleotide DNA probe based on the entire 3.5-kb BglII-XbaI fragment of cadA operon from staphylococcal plasmid pI258 was prepared by using Vector NTI Express software. Under the hybridization conditions of 46 °C, 50 % formamide, and 0.028 M NaCl, the designed cadA probe appeared to be highly specific to the cadA-positive Staphylococcus warneri and Delftia acidovorans isolates tested. The results indicated that the newly designed cadA-targeted DNA probe has potential as a specific, sensitive, and quantitative tool in selecting and in situ screening of potential cadmium biosorbents.