title: Chaotropic solutes cause water stress in Pseudomonas putida.
abstract: Low water availability is the most ubiquitous cause of stress for terrestrial plants, animals and microorganisms, and has a major impact on ecosystem function and agricultural productivity. Studies of water stress have largely focused on conditions that affect cell turgor, i.e. induce osmotic stress. We show that chaotropic solutes that do not affect turgor reduce water activity, perturb macromolecule-water interactions and thereby destabilize cellular macromolecules, inhibit growth, and are powerful mediators of water stress in a typical soil bacterium, Pseudomonas putida. Chaotropic solute-induced water stress resulted mostly in the upregulation of proteins involved in stabilization of biological macromolecules and membrane structure. Many environmental pollutants and agricultural products are chaotropic chemicals and thus constitute a previously unrecognised but common form of biological stress in water bodies and soils.
authors.affiliation: Department of Biological Sciences, University of Essex, Colchester, CO4 3SQ, UK. jehalls@essex.ac.uk
authors.forename: John E
authors.initials: JE
authors.lastname: Hallsworth
authors.forename: Sabina
authors.initials: S
authors.lastname: Heim
authors.forename: Kenneth N
authors.initials: KN
authors.lastname: Timmis
mesh_terms: D000222:Adaptation, Physiological; D001426:Bacterial Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D003681:Dehydration; D050356:Lipid Metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D009930:Organic Chemicals / Q000494:pharmacology*; D020543:Proteome / Q000032:analysis / Q000187:drug effects; D016958:Pseudomonas putida / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D018832:Molecular Chaperones; D009930:Organic Chemicals; D020543:Proteome