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BACKGROUND: This study aimed to investigate the effect of cold plasma treatment on the improvement of seed germination and surface sterilization of ginseng seeds. METHODS: Dehisced ginseng (Panax ginseng) seeds were exposed to dielectric barrier discharge (DBD) plasma operated in argon (Ar) or an argon/oxygen mixture (Ar/O2), and the resulting germination and surface sterilization were compared with those of an untreated control group. Bacterial and fungal detection assays were performed for plasma-treated ginseng seeds after serial dilution of surface-washed suspensions. The microbial colonies (fungi and bacteria) were classified according to their phenotypical morphologies and identified by molecular analysis. Furthermore, the effect of cold plasma treatment on the in vitro antifungal activity and suppression of Cylindrocarpon destructans in 4-year-old ginseng root discs was investigated. RESULTS: Seeds treated with plasma in Ar or Ar/O2 exhibited a higher germination rate (%) compared with the untreated controls. Furthermore, the plasma treatment exhibited bactericidal and fungicidal effects on the seed surface, and the latter effect was stronger than the former. In addition, plasma treatment exhibited in vitro antifungal activity against C. destructans and reduced the disease severity (%) of root rot in 4-year-old ginseng root discs. The results demonstrate the stimulatory effect of plasma treatment on seed germination, surface sterilization, and root rot disease suppression in ginseng. CONCLUSION: The results of this study indicate that the cold plasma treatment can suppress the microbial community on the seed surface root rot in ginseng.
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Oxidative stress enhances cellular DNA oxidation and may cause mutations in DNA bases, including 8oxoguanine (8oxoG). Our recent study reported that exposure of cells to nonthermal dielectric barrier discharge (DBD) plasma generates reactive oxygen species and damages DNA. The present study investigated the effect of nonthermal DBD plasma exposure on the formation of 8oxoG in HaCaT human keratinocytes. Cells exposed to DBD plasma exhibited increased level of 8oxoG. In addition, mRNA and protein expression levels of 8oxoguanine glycosylase 1 (OGG1), an 8oxoG repair enzyme, were reduced in plasmaexposed cells. Furthermore, the expression level of nuclear factor erythroid 2related factor 2 (Nrf2), a transcription factor that regulates OGG1 gene expression, was reduced following exposure to DBD plasma. Pretreatment of cells with an antioxidant, Nacetyl cysteine (NAC), prior to plasma exposure suppressed the formation of 8oxoG and restored the expression levels of OGG1 and Nrf2. In addition, phosphorylation of protein kinase B (Akt), which regulates the activation of Nrf2, was reduced following plasma exposure. However, phosphorylation was restored by pretreatment with NAC. These findings suggested that nonthermal DBD plasma exposure generates 8oxoG via inhibition of the AktNrf2OGG1 signaling pathway in HaCaT cells.
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Daño del ADN/efectos de los fármacos , ADN Glicosilasas/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Guanina/análogos & derivados , Gases em Plasma/toxicidad , Regulación hacia Arriba/efectos de los fármacos , Acetilcisteína/farmacología , Línea Celular , ADN/aislamiento & purificación , ADN/metabolismo , ADN Glicosilasas/genética , Ensayo de Inmunoadsorción Enzimática , Guanina/análisis , Guanina/metabolismo , Humanos , Queratinocitos/citología , Queratinocitos/metabolismo , Factor 2 Relacionado con NF-E2/genética , Factor 2 Relacionado con NF-E2/metabolismo , Estrés Oxidativo/efectos de los fármacos , Fosforilación/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Colorectal cancer is a common type of tumor among both men and women worldwide. Conventional remedies such as chemotherapies pose the risk of sideeffects, and in many cases cancer cells develop chemoresistance to these treatments. Nonthermal gas plasma (NTGP) was recently identified as a potential tool for cancer treatment. In this study, we investigated the potential use of NTGP to control SNUC5 human colon carcinoma cells. We hypothesized that NTGP would generate reactive oxygen species (ROS) in these cells, resulting in induction of endoplasmic reticulum (ER) stress. ROS generation, expression of ER stressrelated proteins and mitochondrial calcium levels were analyzed. Our results confirmed that plasmagenerated ROS induce apoptosis in SNUC5 cells. Furthermore, we found that plasma exposure resulted in mitochondrial calcium accumulation and expression of unfolded protein response (UPR) proteins such as glucoserelated protein 78 (GRP78), protein kinase R (PKR)like ER kinase (PERK), and inositolrequiring enzyme 1 (IRE1). Elevated expression of spliced Xbox binding protein 1 (XBP1) and CCAAT/enhancerbinding protein homologous protein (CHOP) further confirmed that ROS generated by NTGP induces apoptosis through the ER stress signaling pathway.
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Neoplasias del Colon/terapia , Proteínas de Choque Térmico/biosíntesis , Gases em Plasma/uso terapéutico , Factor de Transcripción CHOP/biosíntesis , Proteína 1 de Unión a la X-Box/biosíntesis , eIF-2 Quinasa/biosíntesis , Apoptosis/genética , Apoptosis/efectos de la radiación , Calcio/metabolismo , Neoplasias del Colon/genética , Neoplasias del Colon/patología , Chaperón BiP del Retículo Endoplásmico , Estrés del Retículo Endoplásmico/genética , Estrés del Retículo Endoplásmico/efectos de la radiación , Regulación Neoplásica de la Expresión Génica/efectos de la radiación , Proteínas de Choque Térmico/genética , Humanos , Mitocondrias/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Factor de Transcripción CHOP/genética , Respuesta de Proteína Desplegada/genética , Proteína 1 de Unión a la X-Box/genética , eIF-2 Quinasa/genéticaRESUMEN
Atmospheric pressure plasma (APP) has been shown effective in sterilization by reducing the number of viable microbes during surface cleaning, food processing, or human tissue treatment. For safe conduct, the majority of previous research focused on complete abolition of microbes, which may require severe treatments. Our aim is to investigate the minimal treatment conditions necessary for effective inactivation of bacteria in such a manner that the APP treated bacteria would not be able to harm the host cells. For this, we ought to identify the objective criteria to make the bacteria dysfunctional. We choose the motile properties and the host-cell invasion capability as two measures to quantify the pathogenic state of bacteria. In this paper, we investigated how the APP treatment in a minimal dosage affects the activity of Salmonella Typhimurium. At 100 W and 15 kHz for 20 s, the APP treatment effectively suppressed active "run and tumble" type motility and induced formation of abnormally long structures. With 20 s exposure, the bacterial cells failed to cause pyroptosis in the host cells with >90% survival after 12 h of co-incubation. Our results suggest novel measures to evaluate the functional pathogenic state for identifying safe APP treatment conditions.
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Desinfección/métodos , Manipulación de Alimentos , Gases em Plasma/química , Salmonella typhimurium/citología , Presión Atmosférica , Línea Celular Tumoral/microbiología , Proliferación Celular , Supervivencia Celular , Humanos , Pruebas de Sensibilidad Microbiana , Microscopía Electrónica de Rastreo , Nitrógeno/química , Fenotipo , Salmonella typhimurium/patogenicidad , VirulenciaRESUMEN
The microbiological safety, quality changes, and genotoxicity of chicken breasts treated with flexible thin-layer dielectric barrier discharge (FTDBD) plasma inside a sealed package were investigated. Following 10 min plasma treatment, the numbers of total aerobic bacteria, Listeria monocytogenes, Escherichia coli, and Salmonella Typhimurium were reduced by 3.36, 2.14, 2.73, and 2.71 Log CFU/g, respectively. Color L* and b* values increased whereas a* value decreased following plasma treatment with increasing exposure duration. Lipid oxidation was unaffected by plasma treatment. In sensory evaluation, flavor decreased and off-flavor increased with extended plasma exposure time, however, these changes had no effect on acceptability. Increased cohesiveness was the only texture profile analysis parameter that changed following plasma treatment. No genotoxicity was detected in plasma-treated chicken breast using the Salmonella mutagenicity assay. Therefore, FTDBD plasma is applicable since it is able to improve microbiological safety with minimal changes in sensory properties of the chicken breast.
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The aim of this study was to identify the mechanisms through which dielectric-barrier discharge plasma damages human keratinocytes (HaCaT cells) through the induction of oxidative stress. For this purpose, the cells were exposed to surface dielectric-barrier discharge plasma in 70% oxygen and 30% argon. We noted that cell viability was decreased following exposure of the cells to plasma in a time-dependent manner, as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The levels of intracellular reactive oxygen species (ROS) were determined using 2',7'-dichlorodihydrofluorescein diacetate and dihydroethidium was used to monitor superoxide anion production. Plasma induced the generation of ROS, including superoxide anions, hydrogen peroxide and hydroxyl radicals. N-acetyl cysteine, which is an antioxidant, prevented the decrease in cell viability caused by exposure to plasma. ROS generated by exposure to plasma resulted in damage to various cellular components, including lipid membrane peroxidation, DNA breaks and protein carbonylation, which was detected by measuring the levels of 8-isoprostane and diphenyl-1-pyrenylphosphine assay, comet assay and protein carbonyl formation. These results suggest that plasma exerts cytotoxic effects by causing oxidative stress-induced damage to cellular components.
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Argón/efectos adversos , Queratinocitos/patología , Estrés Oxidativo , Oxígeno/efectos adversos , Gases em Plasma/efectos adversos , Línea Celular , Supervivencia Celular , Humanos , Queratinocitos/citología , Queratinocitos/metabolismo , Peroxidación de Lípido , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Isorhamnetin (3-methylquercetin) is a flavonoid derived from the fruits of certain medicinal plants. This study investigated the photoprotective properties of isorhamnetin against cell damage and apoptosis resulting from excessive ultraviolet (UV) B exposure in human HaCaT keratinocytes. Isorhamnetin eliminated UVB-induced intracellular reactive oxygen species (ROS) and attenuated the oxidative modification of DNA, lipids, and proteins in response to UVB radiation. Moreover, isorhamnetin repressed UVB-facilitated programmed cell death in the keratinocytes, as evidenced by a reduction in apoptotic body formation, and nuclear fragmentation. Additionally, isorhamnetin suppressed the ability of UVB light to trigger mitochondrial dysfunction. Taken together, these results indicate that isorhamnetin has the potential to protect human keratinocytes against UVB-induced cell damage and death.
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Excessive ultraviolet (UV) radiation, a constituent of sunlight, can induce multiple types of skin damage. We recently demonstrated that americanin B, a lignin compound, protected cells against hydrogen peroxide (H2O2)-induced damage by exerting antioxidant effects and inhibiting apoptosis. In this study, we investigated the ability of americanin B to protect against cell injury induced by UVB (280-320nm), the most harmful UV wavelengths, in human HaCaT keratinocytes. Americanin B absorbed UVB, eliminated UVB-induced intracellular reactive oxygen species (ROS), and decreased the extent of UVB-induced oxidative modification of lipids, proteins, and DNA. In addition, americanin B inhibited UVB-induced apoptosis, as indicated by reductions in apoptotic body formation and DNA fragmentation. Furthermore, americanin B reversed the depolarization of the mitochondrial membrane induced by UVB exposure. These protective activities were associated with down-regulation of apoptosis-promoting proteins, Bax, caspase-9, and caspase-3 and up-regulation of an apoptosis inhibitor, Bcl-2. These results suggest that americanin B can protect human keratinocytes against UVB-induced cell damage.
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Antioxidantes/farmacología , Daño del ADN/efectos de los fármacos , Dioxanos/farmacología , Apoptosis , Supervivencia Celular , Células Cultivadas , Regulación de la Expresión Génica/efectos de los fármacos , Humanos , Queratinocitos/citología , Queratinocitos/efectos de los fármacos , Queratinocitos/efectos de la radiación , Peroxidación de Lípido/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Rayos UltravioletaRESUMEN
A 2.45 GHz electron cyclotron resonance (ECR) source with a magnetron magnetic field configuration was developed to meet the demand of a hyperthermal neutral beam (HNB) flux on a substrate of more than 1x10(15) cm(-2) s(-1) for industrial applications. The parameters of the operating pressure, ion density, electron temperature, and distance between the neutralization plate and the substrate for the HNB source are specified in a theoretical analysis. The electron temperature and the ion density are measured to characterize the ECR HNB source using a Langmuir probe and optical emission spectroscopy. The parameters of the ECR HNB source are in good agreement with the theoretically specified parameters.
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A Multi-Purpose Plasma (MP(2)) facility has been renovated from Hanbit mirror device [Kwon et al., Nucl. Fusion 43, 686 (2003)] by adopting the same philosophy of diversified plasma simulator (DiPS) [Chung et al., Contrib. Plasma Phys. 46, 354 (2006)] by installing two plasma sources: LaB(6) (dc) and helicon (rf) plasma sources; and making three distinct simulators: divertor plasma simulator, space propulsion simulator, and astrophysics simulator. During the first renovation stage, a honeycomblike large area LaB(6) (HLA-LaB(6)) cathode was developed for the divertor plasma simulator to improve the resistance against the thermal shock fragility for large and high density plasma generation. A HLA-LaB(6) cathode is composed of the one inner cathode with 4 in. diameter and the six outer cathodes with 2 in. diameter along with separate graphite heaters. The first plasma is generated with Ar gas and its properties are measured by the electric probes with various discharge currents and magnetic field configurations. Plasma density at the middle of central cell reaches up to 2.6 x 10(12) cm(-3), while the electron temperature remains around 3-3.5 eV at the low discharge current of less than 45 A, and the magnetic field intensity of 870 G. Unique features of electric property of heaters, plasma density profiles, is explained comparing with those of single LaB(6) cathode with 4 in. diameter in DiPS.
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Electroquímica/instrumentación , Electrodos , Gases/química , Calefacción/instrumentación , Electroquímica/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Calefacción/métodos , Calor , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
A concerted computational and experimental study has been undertaken to probe the conformational structure and excited-state dynamics of bis(9-fluorenyl)methane (BFM). We have observed that the relative intensity of the delayed excimer fluorescence of BFM is greatly enhanced in comparison with that of the normal fluorescence. This is presumably because the relative concentration of the triplet excimer is enhanced in comparison with the singlet excimer. B3LYP DFT/6-31G(d) calculations indicate that the sandwich conformer of BFM in the singlet ground state is unstable, whereas that in the triplet excited state has a bound state, being very slightly higher in internal and Gibbs free energies than that of the lowest state of the near-orthogonal conformer.