Low temperature atmospheric pressure plasma has emerged as a very powerful technology to improve agricultural and food industries. Recently, various types of atmospheric pressure plasmas have applied to seed germination and plant growth. In this study, the barley (Hordeum vulgare) seeds have treated using a surface dielectric barrier discharge to investigate the biological effects on the seed germination, plant growth and functional metabolites. It was observed that the seed surface was cracked and eroded after plasma treatment, while the surface of non‐treated seed was intact. The growth of plasma treated barley was increased by at the lowest 15% and at the highest 110% depending on plasma treatment duration, respectively. GABA content of plasma treated Saechal barley was slightly increased under no germination process, while DPPH activity was decreased at the same condition. Plasma may affect the biological effects on seed germination, plant growth, and changing of secondary metabolites through physical and chemical interactions, but it needs further experimental investigations and verified data to clarify their mechanisms.

Crops during their early growth stages are vulnerable to a wide range of environmental stressors; thus, earlier seed invigoration and seedling establishment are essential in crop production. As an alternative to synthetic chemical treatments, plasma technology could be one of the emerging technologies to enhance seed germination and seedling vigor by managing environmental stressors. Recent studies have shown its beneficial effects in various stress conditions, suggesting that plasma treatment can be used for early crop stress management. This paper reviewed the effects of different types of plasma treatments on plant responses in terms of the seed surface environment (seed scarification and pathogen inactivation) and physiological processes (an enhanced antioxidant system and activated defense response) during the early growth stages of plants. As a result, plasma treatment can enhance seed invigoration and seedling establishment by alleviating the adverse effects of environmental stressors such as drought, salinity, and pathogen infection. More information on plasma applications and their mechanisms against a broad range of stressors is required to establish a better plasma technology for early crop stress management.

Barley sprouts are 5 to 20 day-old grown whole plants that are widely consumed as a functional vegetable due to their health-promoting compounds such as saponarin, γ-Aminobutyric acid (GABA), and policosanols. Recent plasma applications have been a promising approach in the agricultural and food industries to produce bioactive phytochemicals in sprouted crops. Therefore, this study investigated the plasma effects on the whole plant and its bioactive phytochemicals compared with those of an untreated control in barley sprouts. The optimal plasma exposure during seed germination can change physical and chemical properties of fully hydrated seeds of barley, accelerate the early growth of its sprouts and enhance bioactive phytochemicals in the sprouts. Thus, a single 6 min exposure of the plasma enhanced the fresh weight of whole barley seedlings by 137.5% of the untreated control at 9 d after the exposure and enhanced the contents of the primary metabolites including soluble sugars and free amino acids, and secondary metabolites including special phytochemicals such as saponarin, GABA, and policosanols. Therefore, our results suggest that the optimal plasma exposure can be used as a promising seed priming technique for the whole plant and the bioactive phytochemicals of barley sprouts.

The therapeutic benefits offered by 5-fluorouracil (5-FU) are limited because of the acquisition of drug resistance, the main cause of treatment failure and metastasis. The ability of the cancer cells to undergo epithelial-mesenchymal transition (EMT) contributes significantly to cancer metastatic potential and chemo-resistance. However, the underlying molecular mechanisms of 5-FU-resistance have remained elusive. Here, we show that reactive oxygen species (ROS), produced by dual oxidase 2 (DUOX2), promote 5-FU-induced EMT. First, we showed that 5-FU–resistant SNUC5 colon cancer cells (SNUC5/FUR cells) undergo EMT by analyzing the expression of EMT markers such as N-cadherin, vimentin and E-cadherin. In addition, we found that the resistant cells expressed higher levels of Snail, Slug, Twist and Zeb1, which are all critical EMT regulators and had enhanced migratory and invasive capabilities. Furthermore, SNUC5/FUR cells had increased level of DUOX2, resulting in increased ROS level. This effect was due to the enhanced binding of the ten eleven translocation 1 (TET1) demethylase to the DUOX2 promoter in the SNUC5/FUR cells. Importantly, silencing of TET1 reversed the effects of 5-FU on the cells. Finally, the antioxidant N-acetylcysteine attenuated the effects of 5-FU on EMT and metastasis. Our study demonstrates the existence of a TET1/DUOX2/ROS/EMT axis that could play a role in colon cancer chemo-resistance and the aggressiveness of this cancer.

The quality of avian semen is an important economic trait in poultry production. The present study examines the in vitro effects of non-thermal dielectric barrier discharge plasma on chicken sperm to determine the plasma conditions that can produce the optimum sperm quality. Exposure to 11.7 kV of plasma for 20 s is found to produce maximum sperm motility by controlling the homeostasis of reactive oxygen species and boosting the release of adenosine triphosphate and respiratory enzyme activity in the mitochondria. However, prolonged exposure or further increase in plasma potential impairs the sperm quality in a time- and dose-dependent manner. Optimal plasma treatment of sperm results in upregulated mRNA and protein expression of antioxidant defense-related and energetic metabolism-related genes by increasing their demethylation levels. However, 27.6 kV of plasma exerts significant adverse effects. Thus, our findings indicate that appropriate plasma exposure conditions improve chicken sperm motility by regulating demethylation levels of genes involved in antioxidant defense and energetic metabolism.

Non-thermal plasma treatment is an emerging innovative technique with a wide range of biological applications. This study was conducted to investigate the effect of a non-thermal dielectric barrier discharge plasma technique on immature chicken Sertoli cell (SC) viability and the regulatory role of microRNA (miR)-7450. Results showed that plasma treatment increased SC apoptosis in a time- and dose-dependent manner. Plasma-induced SC apoptosis possibly resulted from the excess production of reactive oxygen species via the suppression of antioxidant defense systems and decreased cellular energy metabolism through the inhibition of adenosine triphosphate (ATP) release and respiratory enzyme activity in the mitochondria. In addition, plasma treatment downregulated miR-7450 expression and activated adenosine monophosphate-activated protein kinase α (AMPKα), which further inhibited mammalian target of rapamycin (mTOR) phosphorylation in SCs. A single-stranded synthetic miR-7450 antagomir disrupted mitochondrial membrane potential and decreased ATP level and mTOR phosphorylation by targeting the activation of AMPKα, which resulted in significant increases in SC lethality. A double-stranded synthetic miR-7450 agomir produced opposite effects on these parameters and ameliorated plasma-mediated apoptotic effects on SCs. Our findings suggest that miR-7450 is involved in the regulation of plasma-induced SC apoptosis through the activation of AMPKα and the further inhibition of mTOR signaling pathway.

Colorectal cancer is a common type of tumor among both men and women worldwide. Conventional remedies such as chemotherapies pose the risk of side‑effects, and in many cases cancer cells develop chemoresistance to these treatments. Non‑thermal 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 stress‑related proteins and mitochondrial calcium levels were analyzed. Our results confirmed that plasma‑generated 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 glucose‑related protein 78 (GRP78), protein kinase R (PKR)‑like ER kinase (PERK), and inositol‑requiring enzyme 1 (IRE1). Elevated expression of spliced X‑box binding protein 1 (XBP1) and CCAAT/enhancer‑binding protein homologous protein (CHOP) further confirmed that ROS generated by NTGP induces apoptosis through the ER stress signaling pathway.

This study investigated the mutual interaction between the plasma and plasma treated water (PTW). Many works have shown that the plasma treatment decreases the pH of PTW due to nitric oxide electrolyte ion but the interactions between PTW and the plasma are still largely unknown. We investigated the effect of PTW on a plasma as well as the effect of a plasma on PTW using a pin-to-liquid discharge system. It is found that PTW affects not only the chemical properties but also the physical properties of the plasma such as breakdown voltage and concentration of plasma column. The decrease of the liquid surface tension of PTW due to nitric oxide electrolyte ion from the plasma results in the increase of plasma current onto the surface of PTW and vice versa. The feedback process will be continued until the transition from normal discharge to abnormal discharge. These results can be basic data for the development of plasma sources to treat liquids.