ABSTRACT
A Citrobacter sp. originally isolated from metal-polluted soil accumulates heavy metals via metalphosphate deposition utilizing inorganic phosphate liberated via PhoN phosphatase activity. Further strain development was limited by the non-transformability of this environmental isolate. Recombinant Escherichia coli DH5 alpha bearing cloned phoN or the related phoC acquired metal-accumulating ability, which was compared with that of the Citrobacter sp. with respect to removal of uranyl ion (UO2(2+)) from dilute aqueous flows and its deposition in the form of polycrystalline hydrogen uranyl phosphate (HUO2PO4). Subsequently, HUO2PO4-laden cells removed Ni2+ from dilute aqueous flows via intercalation of Ni2+ into the HUO2PO4 lattice. Despite comparable acid phosphatase activity in all three strains, the E. coli DH5 alpha (phoN) construct was superior to Citrobacter N14 in both uranyl and nickel accumulation, while the E. coli DH5 alpha (phoC) construct was greatly inferior in both respects. Expression of phosphatase activity alone is not the only factor that permits efficient and prolonged metal phosphate accumulation, and the data highlight possible differences in the PhoN and PhoC phosphatases, which are otherwise considered to be related in many respects.
Subject(s)
Escherichia coli/genetics , Nickel/metabolism , Phosphoric Monoester Hydrolases/genetics , Phosphoric Monoester Hydrolases/metabolism , Uranium/metabolism , Water Pollutants, Chemical/metabolism , Biodegradation, Environmental , Citrobacter/enzymology , Citrobacter/genetics , Citrobacter/isolation & purification , Escherichia coli/enzymology , Genes, Bacterial , Soil Microbiology , Soil PollutantsABSTRACT
A method for the high resolution, high sensitivity analysis of polluted air for individual organic compounds is described. Samples collected from 50 mL of ambient air at 87 K (liquid argon) are injected without use of a valve into a silica capillary column which is then temperature programmed from -30 degrees C to 180 degrees C. Hydrocarbons (4 to 10 carbons) as well as carbonyl compounds, chlorinated compounds and terpenes can be identified and quantified. The detection limit, not strongly dependent on carbon number, is estimated to be 0.3 ppbc in a 50 mL sample. Use of small samples eliminates the need to remove water vapor, a procedure which might jeopardize sample integrity.
Subject(s)
Air Pollutants, Occupational/analysis , Chromatography, GasSubject(s)
Air Pollutants , Fluorocarbon Polymers , Fluorocarbons , Air Pollutants/analysis , California , Fluorocarbons/analysisSubject(s)
Air Pollution , California , Chemical Phenomena , Chemistry , Meteorological Concepts , SmogSubject(s)
Air Pollution/analysis , Hydrocarbons, Fluorinated/analysis , California , Chromatography, Gas , Environment , Methane/analysis , Photolysis , Seasons , Smog/analysis , WeatherSubject(s)
Air Pollution/analysis , Aldehydes/analysis , Formaldehyde/analysis , Chemical Phenomena , Chemistry , Chlorides , Colorimetry , Hydrazines , Hydrogen-Ion Concentration , Iron , Methods , Oxidation-Reduction , Sulfates , ThiazolesSubject(s)
Air Pollution/analysis , Aldehydes/analysis , Chemical Phenomena , Chemistry , Chlorides , Colorimetry , Ethanol , Hexylresorcinol , Mercury , Methods , Spectrophotometry , Trichloroacetic AcidSubject(s)
Air Pollution/analysis , Antipyrine , Phenols/analysis , Amines , Chemical Phenomena , Chemistry , Hydrogen-Ion Concentration , Methods , Oxidation-Reduction , Pyrazoles , SpectrophotometryABSTRACT
Infrared spectra of smog aerosol are similar to those of sulfuric acid aerosol, but they do not show the prominent CH and carbonyl bands of organic aerosols from terpenes. Some features of the smog aerosol spectra are not present in the spectra from either type of synthetic aerosol.
