Effects of Fe(II) on anammox community activity and functional genes expression

Four Fe(II) concentrations (0.03, 0.09, 0.12 & 0.75 mM) were tested to investigate the stimulation and inhibition effects of ferrous iron on anammox bacterial activity. RNAs were extracted from the cultures, and the synthesized cDNAs by reverse transcription were used to carry out GeoChip analysis, by which the functional communities and expression level differences in functional genes under different Fe(II) concentrations conditions were obtained, and the response of anammox bacteria to Fe(II) stimulation and inhibition are speculated. Enriched anammox culture was taken out from the parent reactor and used as inoculum. Then four Fe(II) concentrations (0.03, 0.09, 0.12 & 0.75 mM) were applied to four independent experimental cultures. RNAs in 0.03, 0.09 and 0.12 mM Fe(II) cultures were isolated at the end of the experiments, while RNA in 0.75 mM Fe(II) culture was extracted after the inhibition occured. All of the RNAs were reversely transcribed into cDNAs, and then were used to do Geochip analysis.