This work examines the physiologic basis of stress tolerance in bacterial strains of the genus Rhodanobacter that dominate in the acidic and highly metal contaminated near-source subsurface zone of the Oak Ridge Integ...This work examines the physiologic basis of stress tolerance in bacterial strains of the genus Rhodanobacter that dominate in the acidic and highly metal contaminated near-source subsurface zone of the Oak Ridge Integrated Field Research Challenge(ORIFRC)site.Tolerance of R.denitrificans to levels of different stresses were studied in synthetic groundwater medium and R2A broth.Two strains of R.denitrificans,strains 2APBS1T and 116-2,tolerate low to circumneutral pH(4–8),high Uranium(1 mmol/L),elevated levels of nitrate(400 mmol/L)and high NaCl(2.5%).A combination of physiologic traits,such as growth at low pH,increased growth in the presence of high organics concentration,and tolerance of high concentrations of nitrate,NaCl and heavy metals is likely responsible for dominance of Rhodanobacter at the ORIFRC site.Furthermore,extended incubation times and use of low carbon media,better approximating site groundwater conditions,are critical for accurate determination of stress responses.This study expands knowledge of the ecophysiology of bacteria from the genus Rhodanobacter and identifies methodological approaches necessary for acquiring accurate tolerance data.展开更多
基金the US Department of Energy(Grant Nos.DE-FG02-00ER62986 and DE-FG02-07ER64373 to J.E.K.)the Department of Biotechnology,Govt.of India(Grant No.BT/Coord.II/01/03/2016)for their support.Fellowship funding for one of the authors(Dr.Pooja Singh)by the Department of Science and Technology(DST),Government of India,is greatly acknowledged.
文摘This work examines the physiologic basis of stress tolerance in bacterial strains of the genus Rhodanobacter that dominate in the acidic and highly metal contaminated near-source subsurface zone of the Oak Ridge Integrated Field Research Challenge(ORIFRC)site.Tolerance of R.denitrificans to levels of different stresses were studied in synthetic groundwater medium and R2A broth.Two strains of R.denitrificans,strains 2APBS1T and 116-2,tolerate low to circumneutral pH(4–8),high Uranium(1 mmol/L),elevated levels of nitrate(400 mmol/L)and high NaCl(2.5%).A combination of physiologic traits,such as growth at low pH,increased growth in the presence of high organics concentration,and tolerance of high concentrations of nitrate,NaCl and heavy metals is likely responsible for dominance of Rhodanobacter at the ORIFRC site.Furthermore,extended incubation times and use of low carbon media,better approximating site groundwater conditions,are critical for accurate determination of stress responses.This study expands knowledge of the ecophysiology of bacteria from the genus Rhodanobacter and identifies methodological approaches necessary for acquiring accurate tolerance data.
