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Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

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ABSTRACT

Herein we are the first to report that single-walled carbon nanotubes (SWCNTs) exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS) generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

No MeSH data available.


Intracellular production of ROS in Arabidopsis mesophyll cells. Plant cells were incubated for 24 h without SWCNTs (negative control) or with 0, 15, 25, 50, 100 μg/ml of SWCNTs and stained with C-400. Fluorescent intensity was monitored by flow cytometry. The intracellular generation of ROS is expressed as the percentage of control. Hydrogen peroxide (H2O2) was used as a positive control. Bars indicate the mean ± SE of two independent experiments.
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Figure 8: Intracellular production of ROS in Arabidopsis mesophyll cells. Plant cells were incubated for 24 h without SWCNTs (negative control) or with 0, 15, 25, 50, 100 μg/ml of SWCNTs and stained with C-400. Fluorescent intensity was monitored by flow cytometry. The intracellular generation of ROS is expressed as the percentage of control. Hydrogen peroxide (H2O2) was used as a positive control. Bars indicate the mean ± SE of two independent experiments.

Mentions: We investigated if SWCNTs causes ROS formation in the Arabidopsis mesophyll cells by using DCF(2',7'-dichlorofluorescin diacetate) fluorescence as a reporter of intracellular oxidant production. As shown in Figure 8, as the concentration of SWCNTs in medium increased, the gradually enhanced DCF response was observed after a 24-h exposure to SWCNTs at concentrations of 0, 15, 25, 50, 100 μg/ml, which highly suggest that highly purified SWCNTs can cause oxidative stress reaction of plant cells.


Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells
Intracellular production of ROS in Arabidopsis mesophyll cells. Plant cells were incubated for 24 h without SWCNTs (negative control) or with 0, 15, 25, 50, 100 μg/ml of SWCNTs and stained with C-400. Fluorescent intensity was monitored by flow cytometry. The intracellular generation of ROS is expressed as the percentage of control. Hydrogen peroxide (H2O2) was used as a positive control. Bars indicate the mean ± SE of two independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211858&req=5

Figure 8: Intracellular production of ROS in Arabidopsis mesophyll cells. Plant cells were incubated for 24 h without SWCNTs (negative control) or with 0, 15, 25, 50, 100 μg/ml of SWCNTs and stained with C-400. Fluorescent intensity was monitored by flow cytometry. The intracellular generation of ROS is expressed as the percentage of control. Hydrogen peroxide (H2O2) was used as a positive control. Bars indicate the mean ± SE of two independent experiments.
Mentions: We investigated if SWCNTs causes ROS formation in the Arabidopsis mesophyll cells by using DCF(2',7'-dichlorofluorescin diacetate) fluorescence as a reporter of intracellular oxidant production. As shown in Figure 8, as the concentration of SWCNTs in medium increased, the gradually enhanced DCF response was observed after a 24-h exposure to SWCNTs at concentrations of 0, 15, 25, 50, 100 μg/ml, which highly suggest that highly purified SWCNTs can cause oxidative stress reaction of plant cells.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Herein we are the first to report that single-walled carbon nanotubes (SWCNTs) exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS) generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

No MeSH data available.