Nitrosomonas europaea cells treated with chloromethane for one hour and compared to untreated cells

We analyzed the global transcriptional response of N. europaea when exposed to chloromethane (3.2 mM for 1 h). Chloromethane treatment led to down regulation of 175 genes and up regulation of 67 genes. This treatment was less harmful to the cells than chloroform Keywords: stress response, global transcription, toxin-antitoxin genes We selected chloromethane concentration and exposure time that caused significant changes in cell physiology but without being too severe. Our experiments demonstrated that 3.2 mM chloromethane caused the desired effect. Based on the physiological, proteomic and transcriptional observations, we analyzed the whole-genome transcriptional responses of N. europaea at 1 h after the chloromethane treatment. Cells from treated samples and untreated control samples were collected for RNA extraction and hybridization with Affymetrix microarray GeneChip.