Transcriptional level of Mb in C. sinensis incubated in different oxygen contents. (A) The fold increase was calculated by comparing intensities between experimental and control groups. The Cs Mb transcripts were much higher in the 20% oxygen group than in the 1% oxygen group. The transcriptional level of Cs Mb in the 5% oxygen group was 3-fold higher than that in the 1% oxygen group. (B) Changes of Mb transcript levels in C. sinensis caused by oxidative chemicals. The worms were stimulated with H2O2 (0–1.8 mM) for 1 h at 37 °C. Cs Mb transcript amounts were significantly increased at H2O2 concentrations greater than 0.6 mM. (*p < 0.01).