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New insight into the residual inactivation of Microcystis aeruginosa by dielectric barrier discharge.

Li L, Zhang H, Huang Q - Sci Rep (2015)

Bottom Line: Our results showed that the numbers of both dead and apoptotic cells increased with DBD treatment delay time, and hydrogen peroxide produced by DBD was the main reason for the time-delayed inactivation effect.However, apart from the influence of hydrogen peroxide, the DBD-induced initial injures on the algal cells during the discharge period also played a considerable role in the inactivation of the DBD treated cells, as indicated by the measurement of intracellular reactive oxygen species (ROS) inside the algal cells.We therefore propose an effective approach to utilization of non-thermal plasma technique that makes good use of the residual inactivation effect to optimize the experimental conditions in terms of discharge time and delay time, so that more efficient treatment of cyanobacterial blooms can be achieved.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Ion Beam Bio-engineering, Institute of Biotechnology and Agriculture Engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, 230031.

ABSTRACT
We report the new insight into the dielectric barrier discharge (DBD) induced inactivation of Microcystis aeruginosa, the dominant algae which caused harmful cyanobacterial blooms in many developing countries. In contrast with the previous work, we employed flow cytometry to examine the algal cells, so that we could assess the dead and living cells with more accuracy, and distinguish an intermediate state of algal cells which were verified as apoptotic. Our results showed that the numbers of both dead and apoptotic cells increased with DBD treatment delay time, and hydrogen peroxide produced by DBD was the main reason for the time-delayed inactivation effect. However, apart from the influence of hydrogen peroxide, the DBD-induced initial injures on the algal cells during the discharge period also played a considerable role in the inactivation of the DBD treated cells, as indicated by the measurement of intracellular reactive oxygen species (ROS) inside the algal cells. We therefore propose an effective approach to utilization of non-thermal plasma technique that makes good use of the residual inactivation effect to optimize the experimental conditions in terms of discharge time and delay time, so that more efficient treatment of cyanobacterial blooms can be achieved.

No MeSH data available.


The identification of three states of the algal cells after DBD treatment without delay.(A) The flow cytometry results of the DBD treated cells; (B) The statistical graph of the flow cytometry results change with discharge time. In the flow cytometry graphs, three regions are indicated: I- live cells; II-apoptotic-like cells; III- dead cells.
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f2: The identification of three states of the algal cells after DBD treatment without delay.(A) The flow cytometry results of the DBD treated cells; (B) The statistical graph of the flow cytometry results change with discharge time. In the flow cytometry graphs, three regions are indicated: I- live cells; II-apoptotic-like cells; III- dead cells.

Mentions: We conducted the DBD experiments using the set-up as shown in Fig. 1. We changed the voltage from 10 to 20 kV, and it was observed that the inactivation rate increased with the discharge voltage, and when the applied voltage was over 16 kV, the inactivation rate was raised significantly (Supplementary Fig. S1). The inactivation effect is also dependent on the working gas of DBD, as we observed that air-DBD was more efficient in activation of M. aeruginosa than argon-DBD (Supplementary Fig. S2). For convenience, in this paper unless otherwise mentioned we only present the data obtained from atmospheric argon-DBD with applied voltage at 16 kV. After the DBD treatment, we employed flow cytometry to examine the DBD-treated algal cells, which were labeled with SYBR green I and/or propidium iodide (PI) for discriminating the cells with intact and damaged membrane, respectively. As seen in Fig. 2, the number of living cells decreases while the number of dead cells increases with discharge time. Strikingly, with the facility of flow cytometry, we discovered that apart from the living and dead cells, there also existed the third state of cells different from the states of living cells and dead cells, and the population of these cells also increased with plasma discharge time.


New insight into the residual inactivation of Microcystis aeruginosa by dielectric barrier discharge.

Li L, Zhang H, Huang Q - Sci Rep (2015)

The identification of three states of the algal cells after DBD treatment without delay.(A) The flow cytometry results of the DBD treated cells; (B) The statistical graph of the flow cytometry results change with discharge time. In the flow cytometry graphs, three regions are indicated: I- live cells; II-apoptotic-like cells; III- dead cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561898&req=5

f2: The identification of three states of the algal cells after DBD treatment without delay.(A) The flow cytometry results of the DBD treated cells; (B) The statistical graph of the flow cytometry results change with discharge time. In the flow cytometry graphs, three regions are indicated: I- live cells; II-apoptotic-like cells; III- dead cells.
Mentions: We conducted the DBD experiments using the set-up as shown in Fig. 1. We changed the voltage from 10 to 20 kV, and it was observed that the inactivation rate increased with the discharge voltage, and when the applied voltage was over 16 kV, the inactivation rate was raised significantly (Supplementary Fig. S1). The inactivation effect is also dependent on the working gas of DBD, as we observed that air-DBD was more efficient in activation of M. aeruginosa than argon-DBD (Supplementary Fig. S2). For convenience, in this paper unless otherwise mentioned we only present the data obtained from atmospheric argon-DBD with applied voltage at 16 kV. After the DBD treatment, we employed flow cytometry to examine the DBD-treated algal cells, which were labeled with SYBR green I and/or propidium iodide (PI) for discriminating the cells with intact and damaged membrane, respectively. As seen in Fig. 2, the number of living cells decreases while the number of dead cells increases with discharge time. Strikingly, with the facility of flow cytometry, we discovered that apart from the living and dead cells, there also existed the third state of cells different from the states of living cells and dead cells, and the population of these cells also increased with plasma discharge time.

Bottom Line: Our results showed that the numbers of both dead and apoptotic cells increased with DBD treatment delay time, and hydrogen peroxide produced by DBD was the main reason for the time-delayed inactivation effect.However, apart from the influence of hydrogen peroxide, the DBD-induced initial injures on the algal cells during the discharge period also played a considerable role in the inactivation of the DBD treated cells, as indicated by the measurement of intracellular reactive oxygen species (ROS) inside the algal cells.We therefore propose an effective approach to utilization of non-thermal plasma technique that makes good use of the residual inactivation effect to optimize the experimental conditions in terms of discharge time and delay time, so that more efficient treatment of cyanobacterial blooms can be achieved.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Ion Beam Bio-engineering, Institute of Biotechnology and Agriculture Engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences, 230031.

ABSTRACT
We report the new insight into the dielectric barrier discharge (DBD) induced inactivation of Microcystis aeruginosa, the dominant algae which caused harmful cyanobacterial blooms in many developing countries. In contrast with the previous work, we employed flow cytometry to examine the algal cells, so that we could assess the dead and living cells with more accuracy, and distinguish an intermediate state of algal cells which were verified as apoptotic. Our results showed that the numbers of both dead and apoptotic cells increased with DBD treatment delay time, and hydrogen peroxide produced by DBD was the main reason for the time-delayed inactivation effect. However, apart from the influence of hydrogen peroxide, the DBD-induced initial injures on the algal cells during the discharge period also played a considerable role in the inactivation of the DBD treated cells, as indicated by the measurement of intracellular reactive oxygen species (ROS) inside the algal cells. We therefore propose an effective approach to utilization of non-thermal plasma technique that makes good use of the residual inactivation effect to optimize the experimental conditions in terms of discharge time and delay time, so that more efficient treatment of cyanobacterial blooms can be achieved.

No MeSH data available.