title: Survival and growth in the presence of elevated copper: transcriptional profiling of copper-stressed Pseudomonas aeruginosa.
abstract: Transcriptional profiles of Pseudomonas aeruginosa exposed to two separate copper stress conditions were determined. Actively growing bacteria subjected to a pulse of elevated copper for a short period of time was defined as a "copper-shocked" culture. Conversely, copper-adapted populations were defined as cells actively growing in the presence of elevated copper. Expression of 405 genes changed in the copper-shocked culture, compared to 331 genes for the copper-adapted cultures. Not surprisingly, there were genes identified in common to both conditions. For example, both stress conditions resulted in up-regulation of genes encoding several active transport functions. However, there were some interesting differences between the two types of stress. Only copper-adapted cells significantly altered expression of passive transport functions, down-regulating expression of several porins belonging to the OprD family. Copper shock produced expression profiles suggestive of an oxidative stress response, probably due to the participation of copper in Fenton-like chemistry. Copper-adapted populations did not show such a response. Transcriptional profiles also indicated that iron acquisition is fine-tuned in the presence of copper. Several genes induced under iron-limiting conditions, such as the siderophore pyoverdine, were up-regulated in copper-adapted populations. Interesting exceptions were the genes involved in the production of the siderophore pyochelin, which were down-regulated. Analysis of the copper sensitivity of select mutant strains confirmed the array data. These studies suggest that two resistance nodulation division efflux systems, a P-type ATPase, and a two-component regulator were particularly important for copper tolerance in P. aeruginosa.
authors.affiliation: Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Gail M
authors.initials: GM
authors.lastname: Teitzel
authors.forename: Ashley
authors.initials: A
authors.lastname: Geddie
authors.forename: Susan K
authors.initials: SK
authors.lastname: De Long
authors.forename: Mary Jo
authors.initials: MJ
authors.lastname: Kirisits
authors.forename: Marvin
authors.initials: M
authors.lastname: Whiteley
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Parsek
mesh_terms: D000222:Adaptation, Physiological; D002463:Cell Membrane Permeability; D003300:Copper / Q000378:metabolism / Q000633:toxicity*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006706:Homeostasis; D007501:Iron / Q000378:metabolism; D050296:Microbial Viability; D020411:Oligonucleotide Array Sequence Analysis; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D012329:RNA, Bacterial / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000235:genetics; D014158:Transcription, Genetic; D015032:Zinc / Q000633:toxicity
chemical_list: D012329:RNA, Bacterial; D012333:RNA, Messenger; D003300:Copper; D007501:Iron; D015032:Zinc