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Frederik Hammes - One of the best experts on this subject based on the ideXlab platform.

  • kinetics of Membrane Damage to high hna and low lna nucleic acid bacterial clusters in drinking water by ozone chlorine chlorine dioxide monochloramine ferrate vi and permanganate
    Water Research, 2011
    Co-Authors: Maaike K Ramseier, Urs Von Gunten, Pietro Freihofer, Frederik Hammes
    Abstract:

    Drinking water was treated with ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate to investigate the kinetics of Membrane Damage of native drinking water bacterial cells. Membrane Damage was measured by flow cytometry using a combination of SYBR Green I and propidium iodide (SGI+PI) staining as indicator for cells with permeabilized Membranes and SGI alone to measure total cell concentration. SGI+PI staining revealed that the cells were permeabilized upon relatively low oxidant exposures of all tested oxidants without a detectable lag phase. However, only ozonation resulted in a decrease of the total cell concentrations for the investigated reaction times. Rate constants for the Membrane Damage reaction varied over seven orders of magnitude in the following order: ozone > chlorine > chlorine dioxide approximate to ferrate > permanganate > chloramine. The rate constants were compared to literature data and were in general smaller than previously measured rate constants. This confirmed that Membrane integrity is a conservative and therefore safe parameter for disinfection control. Interestingly, the cell Membranes of high nucleic acid (HNA) content bacteria were Damaged much faster than those of low nucleic acid (LNA) content bacteria during treatment with chlorine dioxide and permanganate. However, only small differences were observed during treatment with chlorine and chloramine, and no difference was observed for ferrate treatment. Based on the different reactivity of these oxidants it was suggested that HNA and LNA bacterial cell Membranes have a different chemical constitution. (C) 2010 Elsevier Ltd. All rights reserved.

  • kinetics of Membrane Damage to high hna and low lna nucleic acid bacterial clusters in drinking water by ozone chlorine chlorine dioxide monochloramine ferrate vi and permanganate
    Water Research, 2011
    Co-Authors: Maaike K Ramseier, Pietro Freihofer, Urs Von Gunten, Frederik Hammes
    Abstract:

    Drinking water was treated with ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate to investigate the kinetics of Membrane Damage of native drinking water bacterial cells. Membrane Damage was measured by flow cytometry using a combination of SYBR Green I and propidium iodide (SGI+PI) staining as indicator for cells with permeabilized Membranes and SGI alone to measure total cell concentration. SGI+PI staining revealed that the cells were permeabilized upon relatively low oxidant exposures of all tested oxidants without a detectable lag phase. However, only ozonation resulted in a decrease of the total cell concentrations for the investigated reaction times. Rate constants for the Membrane Damage reaction varied over seven orders of magnitude in the following order: ozone > chlorine > chlorine dioxide ≈ ferrate > permanganate > chloramine. The rate constants were compared to literature data and were in general smaller than previously measured rate constants. This confirmed that Membrane integrity is a conservative and therefore safe parameter for disinfection control. Interestingly, the cell Membranes of high nucleic acid (HNA) content bacteria were Damaged much faster than those of low nucleic acid (LNA) content bacteria during treatment with chlorine dioxide and permanganate. However, only small differences were observed during treatment with chlorine and chloramine, and no difference was observed for ferrate treatment. Based on the different reactivity of these oxidants it was suggested that HNA and LNA bacterial cell Membranes have a different chemical constitution.

Maaike K Ramseier - One of the best experts on this subject based on the ideXlab platform.

  • kinetics of Membrane Damage to high hna and low lna nucleic acid bacterial clusters in drinking water by ozone chlorine chlorine dioxide monochloramine ferrate vi and permanganate
    Water Research, 2011
    Co-Authors: Maaike K Ramseier, Urs Von Gunten, Pietro Freihofer, Frederik Hammes
    Abstract:

    Drinking water was treated with ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate to investigate the kinetics of Membrane Damage of native drinking water bacterial cells. Membrane Damage was measured by flow cytometry using a combination of SYBR Green I and propidium iodide (SGI+PI) staining as indicator for cells with permeabilized Membranes and SGI alone to measure total cell concentration. SGI+PI staining revealed that the cells were permeabilized upon relatively low oxidant exposures of all tested oxidants without a detectable lag phase. However, only ozonation resulted in a decrease of the total cell concentrations for the investigated reaction times. Rate constants for the Membrane Damage reaction varied over seven orders of magnitude in the following order: ozone > chlorine > chlorine dioxide approximate to ferrate > permanganate > chloramine. The rate constants were compared to literature data and were in general smaller than previously measured rate constants. This confirmed that Membrane integrity is a conservative and therefore safe parameter for disinfection control. Interestingly, the cell Membranes of high nucleic acid (HNA) content bacteria were Damaged much faster than those of low nucleic acid (LNA) content bacteria during treatment with chlorine dioxide and permanganate. However, only small differences were observed during treatment with chlorine and chloramine, and no difference was observed for ferrate treatment. Based on the different reactivity of these oxidants it was suggested that HNA and LNA bacterial cell Membranes have a different chemical constitution. (C) 2010 Elsevier Ltd. All rights reserved.

  • kinetics of Membrane Damage to high hna and low lna nucleic acid bacterial clusters in drinking water by ozone chlorine chlorine dioxide monochloramine ferrate vi and permanganate
    Water Research, 2011
    Co-Authors: Maaike K Ramseier, Pietro Freihofer, Urs Von Gunten, Frederik Hammes
    Abstract:

    Drinking water was treated with ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate to investigate the kinetics of Membrane Damage of native drinking water bacterial cells. Membrane Damage was measured by flow cytometry using a combination of SYBR Green I and propidium iodide (SGI+PI) staining as indicator for cells with permeabilized Membranes and SGI alone to measure total cell concentration. SGI+PI staining revealed that the cells were permeabilized upon relatively low oxidant exposures of all tested oxidants without a detectable lag phase. However, only ozonation resulted in a decrease of the total cell concentrations for the investigated reaction times. Rate constants for the Membrane Damage reaction varied over seven orders of magnitude in the following order: ozone > chlorine > chlorine dioxide ≈ ferrate > permanganate > chloramine. The rate constants were compared to literature data and were in general smaller than previously measured rate constants. This confirmed that Membrane integrity is a conservative and therefore safe parameter for disinfection control. Interestingly, the cell Membranes of high nucleic acid (HNA) content bacteria were Damaged much faster than those of low nucleic acid (LNA) content bacteria during treatment with chlorine dioxide and permanganate. However, only small differences were observed during treatment with chlorine and chloramine, and no difference was observed for ferrate treatment. Based on the different reactivity of these oxidants it was suggested that HNA and LNA bacterial cell Membranes have a different chemical constitution.

Jiyong Park - One of the best experts on this subject based on the ideXlab platform.

  • bacterial inactivation in water dna strand breaking and Membrane Damage induced by ultraviolet assisted titanium dioxide photocatalysis
    Water Research, 2013
    Co-Authors: Kashif Ghafoor, Mei Feng, Jungyeon Hong, Jiyong Park
    Abstract:

    The effects of UV-assisted TiO2-photocatalytic oxidation (PCO) inactivation of pathogenic bacteria (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella typhimurium) in a liquid culture using different domains of UV irradiation (A, B and C) were evaluated. Structural changes in super-coiled plasmid DNA (pUC19) and genomic DNA of E. coli were observed using gel electrophoresis to demonstrate the photodynamic DNA strand breaking activity of UV-assisted TiO2-PCO. Membrane Damage in bacterial cells was observed using both a scanning electron microscope (SEM) and a confocal laser scanning microscope (CLSM). Both UVC-TiO2-PCO and UVC alone resulted in an earlier bactericidal phase (initial counts of approximately 6 log CFU/mL) in 60 s and 90 s, respectively, in liquid culture. UVC-TiO2-PCO treatment for 6 min converted all plasmid DNA to the linear form; however, under UVC irradiation alone, super-coiled DNA remained. Prolonged UVC-TiO2-PCO treatment resulted in structural changes in genomic DNA from E. coli. SEM observations revealed that bacteria suffered severe visible cell Damage after UVC-TiO2-PCO treatment for 30-60 mm. S. typhimurium cells showed visible Damage after 30 min, which was confirmed using CLSM. All treated cells were stained red using propidium iodide under a fluorescent light. (C) 2013 Elsevier Ltd. All rights reserved.

  • bacterial inactivation in water dna strand breaking and Membrane Damage induced by ultraviolet assisted titanium dioxide photocatalysis
    Water Research, 2013
    Co-Authors: Soohyun Kim, Mei Feng, Jungyeon Hong, Kashif Ghafoor, Joo Young Lee, Dongun Lee, Jiyong Park
    Abstract:

    The effects of UV-assisted TiO2-photocatalytic oxidation (PCO) inactivation of pathogenic bacteria (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella typhimurium) in a liquid culture using different domains of UV irradiation (A, B and C) were evaluated. Structural changes in super-coiled plasmid DNA (pUC19) and genomic DNA of E. coli were observed using gel electrophoresis to demonstrate the photodynamic DNA strand breaking activity of UV-assisted TiO2-PCO. Membrane Damage in bacterial cells was observed using both a scanning electron microscope (SEM) and a confocal laser scanning microscope (CLSM). Both UVC-TiO2-PCO and UVC alone resulted in an earlier bactericidal phase (initial counts of approximately 6 log CFU/mL) in 60 s and 90 s, respectively, in liquid culture. UVC-TiO2-PCO treatment for 6 min converted all plasmid DNA to the linear form; however, under UVC irradiation alone, super-coiled DNA remained. Prolonged UVC-TiO2-PCO treatment resulted in structural changes in genomic DNA from E. coli. SEM observations revealed that bacteria suffered severe visible cell Damage after UVC-TiO2-PCO treatment for 30-60 min. S. typhimurium cells showed visible Damage after 30 min, which was confirmed using CLSM. All treated cells were stained red using propidium iodide under a fluorescent light.

Urs Von Gunten - One of the best experts on this subject based on the ideXlab platform.

  • kinetics of Membrane Damage to high hna and low lna nucleic acid bacterial clusters in drinking water by ozone chlorine chlorine dioxide monochloramine ferrate vi and permanganate
    Water Research, 2011
    Co-Authors: Maaike K Ramseier, Pietro Freihofer, Urs Von Gunten, Frederik Hammes
    Abstract:

    Drinking water was treated with ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate to investigate the kinetics of Membrane Damage of native drinking water bacterial cells. Membrane Damage was measured by flow cytometry using a combination of SYBR Green I and propidium iodide (SGI+PI) staining as indicator for cells with permeabilized Membranes and SGI alone to measure total cell concentration. SGI+PI staining revealed that the cells were permeabilized upon relatively low oxidant exposures of all tested oxidants without a detectable lag phase. However, only ozonation resulted in a decrease of the total cell concentrations for the investigated reaction times. Rate constants for the Membrane Damage reaction varied over seven orders of magnitude in the following order: ozone > chlorine > chlorine dioxide ≈ ferrate > permanganate > chloramine. The rate constants were compared to literature data and were in general smaller than previously measured rate constants. This confirmed that Membrane integrity is a conservative and therefore safe parameter for disinfection control. Interestingly, the cell Membranes of high nucleic acid (HNA) content bacteria were Damaged much faster than those of low nucleic acid (LNA) content bacteria during treatment with chlorine dioxide and permanganate. However, only small differences were observed during treatment with chlorine and chloramine, and no difference was observed for ferrate treatment. Based on the different reactivity of these oxidants it was suggested that HNA and LNA bacterial cell Membranes have a different chemical constitution.

Pietro Freihofer - One of the best experts on this subject based on the ideXlab platform.

  • kinetics of Membrane Damage to high hna and low lna nucleic acid bacterial clusters in drinking water by ozone chlorine chlorine dioxide monochloramine ferrate vi and permanganate
    Water Research, 2011
    Co-Authors: Maaike K Ramseier, Urs Von Gunten, Pietro Freihofer, Frederik Hammes
    Abstract:

    Drinking water was treated with ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate to investigate the kinetics of Membrane Damage of native drinking water bacterial cells. Membrane Damage was measured by flow cytometry using a combination of SYBR Green I and propidium iodide (SGI+PI) staining as indicator for cells with permeabilized Membranes and SGI alone to measure total cell concentration. SGI+PI staining revealed that the cells were permeabilized upon relatively low oxidant exposures of all tested oxidants without a detectable lag phase. However, only ozonation resulted in a decrease of the total cell concentrations for the investigated reaction times. Rate constants for the Membrane Damage reaction varied over seven orders of magnitude in the following order: ozone > chlorine > chlorine dioxide approximate to ferrate > permanganate > chloramine. The rate constants were compared to literature data and were in general smaller than previously measured rate constants. This confirmed that Membrane integrity is a conservative and therefore safe parameter for disinfection control. Interestingly, the cell Membranes of high nucleic acid (HNA) content bacteria were Damaged much faster than those of low nucleic acid (LNA) content bacteria during treatment with chlorine dioxide and permanganate. However, only small differences were observed during treatment with chlorine and chloramine, and no difference was observed for ferrate treatment. Based on the different reactivity of these oxidants it was suggested that HNA and LNA bacterial cell Membranes have a different chemical constitution. (C) 2010 Elsevier Ltd. All rights reserved.

  • kinetics of Membrane Damage to high hna and low lna nucleic acid bacterial clusters in drinking water by ozone chlorine chlorine dioxide monochloramine ferrate vi and permanganate
    Water Research, 2011
    Co-Authors: Maaike K Ramseier, Pietro Freihofer, Urs Von Gunten, Frederik Hammes
    Abstract:

    Drinking water was treated with ozone, chlorine, chlorine dioxide, monochloramine, ferrate(VI), and permanganate to investigate the kinetics of Membrane Damage of native drinking water bacterial cells. Membrane Damage was measured by flow cytometry using a combination of SYBR Green I and propidium iodide (SGI+PI) staining as indicator for cells with permeabilized Membranes and SGI alone to measure total cell concentration. SGI+PI staining revealed that the cells were permeabilized upon relatively low oxidant exposures of all tested oxidants without a detectable lag phase. However, only ozonation resulted in a decrease of the total cell concentrations for the investigated reaction times. Rate constants for the Membrane Damage reaction varied over seven orders of magnitude in the following order: ozone > chlorine > chlorine dioxide ≈ ferrate > permanganate > chloramine. The rate constants were compared to literature data and were in general smaller than previously measured rate constants. This confirmed that Membrane integrity is a conservative and therefore safe parameter for disinfection control. Interestingly, the cell Membranes of high nucleic acid (HNA) content bacteria were Damaged much faster than those of low nucleic acid (LNA) content bacteria during treatment with chlorine dioxide and permanganate. However, only small differences were observed during treatment with chlorine and chloramine, and no difference was observed for ferrate treatment. Based on the different reactivity of these oxidants it was suggested that HNA and LNA bacterial cell Membranes have a different chemical constitution.