title: Stress resistance of Escherichia coli and Bacillus subtilis is modulated by auxins.
abstract: Two bacterial species, Gram-negative Escherichia coli and Gram-positive Bacillus subtilis, were exposed to different auxins to examine possible effects of these substances on bacterial stress tolerance. Bacterial resistance to UV irradiation, heat shock, and streptomycin was assessed with and without previous exposure to the following auxins: indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), and 1-naphthalene acetic acid (NAA). Escherichia coli and B. subtilis cultures pretreated with any of the 3 auxins survived UV irradiation better than the untreated cultures. Also, B. subtilis cultures pretreated with IBA or NAA survived prolonged heat exposure better than the untreated cultures, while IAA pretreatment had no effect on heat shock survival. In contrast, auxin pretreatment rendered E. coli more sensitive to heat shock. Escherichia coli cultures pretreated with auxins were also more sensitive to streptomycin, while auxin pretreatment had no effect on sensitivity of B. subtilis to streptomycin. These results show that auxins may either enhance or reduce bacterial tolerance to different stressors, depending on the bacterial species and the type and level of the stress. Auxins usually had similar effects on the same bacterial species in cases when the same type and level of stress were applied.
authors.affiliation: a Department of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia.
authors.forename: J
authors.initials: J
authors.lastname: Repar
authors.forename: S
authors.initials: S
authors.lastname: Šućurović
authors.forename: K
authors.initials: K
authors.lastname: Zahradka
authors.forename: D
authors.initials: D
authors.lastname: Zahradka
authors.forename: M
authors.initials: M
authors.lastname: Ćurković-Perica
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects* / Q000528:radiation effects; D004926:Escherichia coli / Q000187:drug effects* / Q000528:radiation effects; D018869:Heat-Shock Response / Q000187:drug effects; D007210:Indoleacetic Acids / Q000494:pharmacology*; D007211:Indoles / Q000494:pharmacology; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D013307:Streptomycin / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects*; D014466:Ultraviolet Rays
chemical_list: D000900:Anti-Bacterial Agents; D007210:Indoleacetic Acids; D007211:Indoles; D009280:Naphthaleneacetic Acids; C014612:indolebutyric acid; C034182:1-naphthaleneacetic acid; C030737:indoleacetic acid; D013307:Streptomycin