• Molecules and Cells
• /
• v.26 no.1
• /
• pp.18-25
• /
• 2008

Arsenic trioxide (ATO) can affect many biological functions such as apoptosis and differentiation in various cells. We investigated the involvement of ROS and GSH in ATO-induced HeLa cell death using ROS scavengers, especially N-acetylcysteine (NAC). ATO increased intracellular ${O_2}^{{\cdot}-}$ levels and reduced intracellular GSH content. The ROS scavengers, Tempol, Tiron and Trimetazidine, did not significantly reduce levels of ROS or GSH depletion in ATO-treated HeLa cells. Nor did they reduce the apoptosis induced by ATO. In contrast, treatment with NAC reduced ROS levels and GSH depletion in the ATO-treated HeLa cells and prevented ATO-induced apoptosis. Treatment with exogenous SOD and catalase reduced the depletion of GSH content in ATO-treated cells. Catalase strongly protected the cells from ATO-induced apoptosis. In addition, treatment with SOD, catalase and NAC slightly inhibited the G1 phase accumulation induced by ATO. In conclusion, NAC protects HeLa cells from apoptosis induced by ATO by up-regulating intracellular GSH content and partially reducing the production of ${O_2}^{{\cdot}-}$.

• Plant Biotechnology Reports
• /
• v.2 no.1
• /
• pp.21-31
• /
• 2008

In plants, the oxygen generated by photosynthesis can be excited to form reactive oxygen species (ROS) under excessive sunlight. Excess ROS including singlet oxygen ($^1O_2$) inhibit the growth, development and photosynthesis of plants. To isolate ROS-resistant crop plants, we used paraquat (PQ), a generator of $O_2{^-}$ as a source of screening and mutagen, and obtained two PQ-resistant lines in Pisum sativum, namely R3-1 and R3-2. Both lines showed greater resistance to PQ than their wild type (WT) siblings with respect to germination, root growth, and shoot growth. Biochemical analysis showed differences in these lines, in which ROS-scavenging enzymes undergo changes with a distinguishable increase in Mn-SOD. We further observed that the cytosolic catalases (CATs) in leaves in both lines were shifted in a native-PAGE analysis compared with that of the WT, indicating that the release of bound $^1O_2$ was enhanced. Phenotypic analysis revealed distinguishable differences in leaf development, and in flowering time and position. In addition, R3-1 and R3-2 showed shorter individual inter-node lengths, dwarf plant height, and stronger branching compared with the WT. These results suggested that PQ-induced ROS-resistant Pisum have the potential pleiotropic effects on flowering time and stem branching, and that ROS including $^1O_2$ plays not only important roles in plant growth and development as a signal transducer, but also appears as a strong inhibitor for crop yield.

• BMB Reports
• /
• v.52 no.4
• /
• pp.265-270
• /
• 2019

We investigated whether SIRT1 is associated with reactive oxygen species (ROS) accumulation during CK2 downregulation-mediated senescence. SIRT1 overexpression suppressed ROS accumulation, reduced transcription of FoxO3a target genes, and nuclear export and acetylation of FoxO3a, which were induced by CK2 downregulation in HCT116 and MCF-7 cells. Conversely, overexpression of a dominant-negative mutant SIRT1 (H363Y) counteracted decreased ROS levels, increased transcriptional activity of FoxO3a, and increased nuclear import and decreased acetylation of FoxO3a, which were induced by CK2 upregulation. CK2 downregulation destabilized SIRT1 protein via an ubiquitin-proteasome pathway in human cells, whereas CK2 overexpression reduced ubiquitination of SIRT1. Finally, the SIRT1 activator resveratrol attenuated the accumulation of ROS and lipofuscin as well as lifespan shortening, and reduced expression of the DAF-16 target gene sod-3, which were induced by CK2 downregulation in nematodes. Altogether, this study demonstrates that inactivation of the SIRT1-FoxO3a axis, at least in part, is involved in ROS generation during CK2 downregulation-mediated cellular senescence and nematode aging.

• The Journal of Asian Finance, Economics and Business
• /
• v.7 no.1
• /
• pp.47-58
• /
• 2020

The research aims to investigate the determinants of the financial performance of 1343 Vietnamese companies categorized into six different industries listed on the Vietnamese Stock Exchange over a four-year period from 2014 to 2017 using STATA software. Those determinants include firm size, liquidity, solvency, financial leverage, and financial adequacy while the financial performance is evaluated by three different ratios: return on assets (ROA), return on equity (ROE), and return on sales (ROS). The research results from these companies during the given period indicate that: (1) Firm size has a positive impact on both ROA and ROS, especially ROA but it has the opposite effect on ROE, (2) Adequacy ratio impacts positively on ROA and ROS but negatively on ROE, (3) Financial leverage considerably negative influences on ROE and ROS but positively impacts on ROA, (4) Liquidity has a positive effect on both ROA and ROE but a negative one on ROS and (5) Solvency has a positive impact on ROA and ROS but the negative impact on ROE. Furthermore, agriculture accounted for the highest percentage of profitability at the beginning, which was replaced by service for ROA but manufacture for ROE from 2016 to 2017 as opposed to the least in transportation.

• Environmental Analysis Health and Toxicology
• /
• v.13 no.1_2
• /
• pp.1-9
• /
• 1998

The ROS-producing potency of chromium compounds of several oxidation states were determined in the H4 cells. $K_2Cr_2O_7$ as Cr (VI), synthetic Cr (V) compounds and Cr (III) as TPP produced high level of ROS. However, ROS values of Cr-picolinate as Cr (III), CrCl$_2$, CrCI$_2$, were almost equal to the control. The effects of physiological antioxidants compounds which react with free radicals were examined for their effects on chromate-induced production of reactive oxygen species (ROS) in A549 cells after the addition of $K_2Cr_2O_7$. The compounds used were vitamin C (ascorbate), vitamin E ($\alpha$-tocopherol), superoxide dismutase (SOD) and catalase. The preincubation of ascorbate (200uM) with A549 cells for 20hr resulted in a significant reduction of hexavalent chromate(100uM) induced ROS. However, there is no effects of preincubation of the cells with vitamin E succinate (10 and 20uM, 20hr) on the ROS production. Also, the effects of Cr (VI) on the cell cycle of A549 cells was measured by adding the DNA intercalating agent, propidium iodide. S phase of the cell cycle was increased by the chromium (VI) compounds up to 20uM indicating toxicity or possible mitogenic action of the cell. The shoulder in Go/G1 phase at 20uM Cr (VI) with 24 hr treatment indicates apoptosis.

• Journal of Plant Biotechnology
• /
• v.38 no.1
• /
• pp.22-29
• /
• 2011

Although reactive oxygen species (ROS) are inevitable by-products of many redox reactions in eukaryotic cells, they play a crucial role as signaling molecules in many cellular processes for development and defense response to abiotic stresses. The biphasic ROS production which was peaked twice in a first transient phase and a second massive phase was occurred after treatment of abiotic stress such as oxidative stress, high salinity. This biphasic generation of ROS was followed by the biphasic production of stress hormone, ethylene. The mechanism of interactions between ROS and ethylene biosynthesis is studied in tobacco (Nicotiana tabaccum L.) plants under the abiotic stresses. The stress-induced ethylene production was significantly inhibited in RbohD-AS and RbohF-AS, in which antisense expression of NADPH oxidase genes was performed. The accumulation of ROS, which was determined by DAB and DCFH-DA staining, was significantly decreased after abiotic stresses in transgenic plants. The suppression of signaling with ethylene and ROS induced more tolerance in response to abiotic stress. The transgenic plants were more tolerant in MS medium supplemented with salinity stress in contrast with wild-type. Stress-induced cell damage determined by DNA fragmentation was decreased at phase II in those transgenic plants. Therefore, the first burst of ROS is more responsible for making a role as a signaling molecule during stress-induced response. These results suggested that ethylene and ROS act in a positive feedback cycle that results in mutual enhancement of ethylene and ROS production during stress-induced cell death.

• Archives of Pharmacal Research
• /
• v.25 no.5
• /
• pp.675-680
• /
• 2002

In order to investigate the underlying mechanism of HCI in oesophagitis, the inflammatory response to HCI was observed in RBL-2H3 mast cells. Rat basophilic leukemia (RBL-2H3) cells were used to measure histamine release, arachidonic acid (AA) release, reactive oxygen species (ROS) and peroxynitrite generation induced by HCI. Exogenous HCl increased the level of histamine release and ROS generation in a dose dependent manner, whereas it decreased the spontaneous release of [$^3$H] M and the spontaneous production of peroxynitrite. Mepacrine (10 $\mu$M), oleyloxyethyl phosphorylcholine (10 $\mu$M) and bromoenol lactone (10 $\mu$M) did not affect both the level of histamine release and ROS generation induced by HCI. U73122 (1 $\mu$M), a specific phospholipase C (PLC) inhibitor did not have any influence on level of histamine release and ROS generation. Propranolol (200 $\mu$M), a phospholipase D (PLD) inhibitor, and neomycin (1 mM), a nonspecific PLC and PLD inhibitor, significantly inhibited both histamine release and ROS generation. Diphenyleneiodonium (10 $\mu$M), a NADPH oxidase inhibitor, and tiron (5 mM), an intracellular ROS scavenger significantly inhibited the HCI-induced histamine release and ROS generation. These findings suggest that the inflammatory responses to HCI is related to histamine release and ROS generation, and that the ROS generation by HCI may be involved in histamine release via the PLD pathway in RBL-2H3 cells.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.10
• /
• pp.1386-1394
• /
• 2013

In our previous study, the 25-mer antimicrobial peptide pleurocidin (Ple) had been thought to induce apoptosis in Candida albicans. This study demonstrated that reactive oxygen species (ROS) production was a major cause of Ple-induced apoptosis. Four truncated analogs were synthesized to understand the functional roles in the N- and C-terminal regions of Ple on the apoptosis. Ple, Ple (4-25), Ple (1-22), and Ple (1-19) produced ROS, including hydroxyl radicals, on the order of [Ple > Ple (1-22) > Ple (4-25) > Ple (1-19)], whereas Ple (7-25) did not induce any ROS production. The results suggested that the N-terminal deletion affected the ROS-inducing activities much more than that of the C-terminal deletion, and net hydrophobicity [Ple > Ple (1-22) > Ple (4-25) > Ple (1-19) > Ple (7-25)] was related to ROS generation rather than other primary factors like net charge. Hence, we focused on the N-terminal-truncated peptides, Ple (4-25) and Ple (7-25), and examined other apoptotic features, including mitochondrial membrane depolarization, caspase activation, phosphatidylserine externalization, and DNA and nuclear fragmentation. The results also confirmed the disappearance of apoptotic activity of Ple (7-25) by the truncation of the N-terminal region (1-6) and the specific activity patterns between Ple and analogs. In conclusion, the N-terminal region of Ple played an important role in apoptosis.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.31 no.4
• /
• pp.57-66
• /
• 2003

The purpose of this study is to evaluate the resource value of existing mud flats in JANGWHARI, KANGWHADO, as strategies for ecotourism. The research methods used in this study are Limits of Acceptable Change(LAC), and Recreation Opportunity Spectrum(ROS). The LAC process draws attention to the existing area conditions that are judged to be acceptable. Managers must define desired area conditions and undertake actions to maintain or achieve these conditions. The ROS is within each of the recreation opportunity classes identified as being used at the regional level. The Results of this study are as follows: 1) The Opportunity Class of the ROS is ecological, physical, social, managerial setting as primitive, semi-primitive. non-motorized, semi-primitive$.$motorized, and roaded natural. 2) The indicator of the LAC is ecological, physical, social, and managerial setting; the indicator of ecological is wildlife populations, water quality, road paving; the indicator of physical is facilities; the indicator of social is visitor needs for knowledge, adventure, eco-experience, and environmental education programs; and, the indicator of managerial is limits of law, and degree of management. 3) Currently, the Opportunity Class of the ROS of JANGWHARI, KANGWHADO is levels II-III, and the Opportunity Class of the suggested ROS is levels I-II. 4) This paper describes strategies for mud flat area management: detection of water quality, resolving problems of equipment, supply of both environmental education programs and guide equipment.

• YAKHAK HOEJI
• /
• v.53 no.4
• /
• pp.179-183
• /
• 2009

We explored the role of reactive oxygen species (ROS) in LPS-induced bone loss. LPS was shown to increase the concentration of ROS in osteoclast precursors. The antioxidant decreased osteoclast formation by LPS. Furthermore, the antioxidant decreased NFATc1 expression by LPS, suggesting that ROS mediates NFATc1 expression in the regulation of LPS-induced osteoclast formation. Finally, the antioxidant decreased LPS-induced RANKL mRNA expression in osteoblasts. Taken together, these data indicate that LPS mediates ROS to induce bone loss.