• Nutrition Research and Practice
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• v.17 no.4
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• pp.670-681
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• 2023

BACKGROUND/OBJECTIVES: Oxidative stress is caused by reactive oxygen species and free radicals that accelerate inflammatory responses and exacerbate fatigue. Tormentic acid (TA) has antioxidant and anti-inflammatory properties. Thus, the aim of present study is to determine the fatigue-regulatory effects of TA in H₂O₂-stimulated myoblast cell line, C2C12 cells and treadmill stress test (TST) and forced swimming test (FST) animal models. MATERIALS/METHODS: In the in vitro study, C2C12 cells were pretreated with TA before stimulation with H₂O₂. Then, malondialdehyde (MDA), lactate dehydrogenase (LDH), creatine kinase (CK) activity, tumor necrosis factor (TNF)-α, interleukin (IL)-6, superoxide dismutase (SOD), catalase (CAT), glycogen, and cell viability were analyzed. In the in vivo study, the ICR male mice were administered TA or distilled water orally daily for 28 days. FST and TST were then performed on the last day. In addition, biochemical analysis of the serum, muscle, and liver was performed. RESULTS: TA dose-dependently alleviated the levels of MDA, LDH, CK activity, TNF-α, and IL-6 in H₂O₂-stimulated C2C12 cells without affecting the cytotoxicity. TA increased the SOD and CAT activities and the glycogen levels in H₂O₂-stimulated C2C12 cells. In TST and FST animal models, TA decreased the FST immobility time significantly while increasing the TST exhaustion time without weight fluctuations. The in vivo studies showed that the levels of SOD, CAT, citrate synthase, glycogen, and free fatty acid were increased by TA administration, whereas TA significantly reduced the levels of glucose, MDA, LDH, lactate, CK, inflammatory cytokines, alanine transaminase, aspartate transaminase, blood urea nitrogen, and cortisol compared to the control group. CONCLUSIONS: TA improves fatigue by modulating oxidative stress and energy metabolism in C2C12 cells and animal models. Therefore, we suggest that TA can be a powerful substance in healthy functional foods and therapeutics to improve fatigue.

• Korean Journal of Environment and Ecology
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• v.36 no.2
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• pp.150-164
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• 2022

The objective of this study is to analyze the biodiversity changes and characteristics of the benthic macroinvertebrate community in the Nakdong River with eight weirs, which was constructed as one of the Four Major River Restoration Projects from May to October 2020. The study also includes the analysis of changes in the major groups of benthic macroinvertebrates for about ten years, from 2010 to 2020. The surveys collected 97 species of benthic macroinvertebrates belonging to 83 genera, 52 families, 18 orders, five classes, three phyla, and 128.1 individuals/m². Chironomidae sp. and Tubificidae spp., which are pollutant indicators, dominated throughout the sections. The community analysis result shows the average dominant index and the diversity index of 0.62±0.20 and 1.87±0.63, respectively, and indicated the most stability of the freshwater ecosystem in the upper stream of the Nakdong River. The survey showed dominance by Chironomidae sp. at the center of the Nakdong River weir and the most unstable community in Chilgok and Gangjeong Goryeong weirs. The results of the community stability analysis showed a high distribution of the characteristic group I with high resilience and resistance and small distribution of characteristic group III with low resistance and resilience, indicating a very unstable condition of communities in the Nakdong River weir section. Predators were relatively abundant among the functional feeding groups (FFGs), whereas shredders, gathering-collectors, and filtering-collectors were relatively lower. Among the habitat orientation groups (HOGs), burrowers and climbers were dominant, indicating a wide distribution of groups in ecosystems with low dissolved oxygen. An endangered species level II of Macromia daimoji was found in Sangju and Nakdan weirs. The analysis results for 10 years from 2010 showed that the number of species and populations increased immediately after the dam construction but plummeted in 2016 and are now stabilizing. Chironomidae spp. has been dominant in all sections over the past 10 years, and they are currently maintained at a rate of about 50%. The EPT groups have decreased significantly since 2011, and the Plecoptera and Trichoptera of the group have not yet been restored. The population of Tubificidae spp. showed an increase after construction was completed in 2012 and drastically increased in 2015 and 2020. The species of Cristaria plicata, designated as endangered species level I, has not been observed since 2011 in Hapcheon Changnyeong weir. Moreover, Macromia daimoji was rarely observed in seven weirs until 2015, and it has been confirmed that the current distribution habitat has decreased rapidly.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.1-7
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• 2005

Tidal flats have been regarded to carry out transformation and removal of land-derived organic matter, and this purifying capability of organic matter by tidal flats is one of very important reasons for their conservation. However, integral biogeochemical studies on production and decomposition of organic matter by benthic microbes in tidal flats have been absent in Korea, although the information is indispensable to quantification of the purifying capability. Our major goals in this multidisciplinary research were to understand major biogeochemical processes and rates mediated by diverse groups of microbes dominating material cycles in the tidal flats, and to assess the contribution of benthic microbes to removal of organic matter and nutrients in the tidal flats. Our study sites were Ganghwa and Incheon north-port tidal flats that had been regarded as naturally well reserved and organically polluted, respectively. Our research group measured over 3 years primary production, biomass and community structure of primary producers, abundance and production of bacteria, enzyme activities, distribution of protozoa and protozoan grazing rates, rates of denitrification and sulfate reduction, early sediment diagenesis, primary production and respiration based on oxygen microelectrode. We analyzed major features of each biogeochemical process and their interactions. The results are compiled in the following articles in this special issue: An (2005), Hwang and Cho (2005), Mok et at. (2005), Na and Lee (2005), Yang et at. (2005), and Yoo and Choi (2005).

• 한국체육학회지인문사회과학편
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• v.51 no.3
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• pp.373-382
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• 2012

The purpose of this study is to predict VO₂max with body index and submaximal metabolic responses. The subjects are consisted of 250 male aging from 18 to 34 and we separated them into two groups randomly; 179 for a sample, 71 for a cross-validation group. They went through maximal exercise testing with Bruce protocol, and we measured the metabolic responses in the end of the first(3 minute) and second stage(6 minute). To predict VO₂max, we applied multiple regression analysis to the sample with stepwise method. Model 1's variables are weight, 6 minute HR and 6 minute VO₂(R=0.64, SEE=4.74, CV=11.7%, p<.01), and the equation is VO₂max(ml/kg/min)= 72.256-0.340(Weight)-0.220(6minHR)+0.013(6minVO₂). Model 2's variables are weight, 6 minute HR, 6 minute VO₂, and 6 minute VCO₂(R=0.67, SEE=4.59, CV=11.3%, p<.01), and the equation is VO₂max(ml/kg/min)= 68.699-0.277(Weight) -0.206(6minHR)+0.020(6minVO₂)-0.009(6minVCO₂). And the result did not show multicolinearity for both models. Model 2 demonstrated more correlation compared to Model 1. However, when we conducted cross-validation of those models with 71 men, measured VO₂max and estimated VO₂ Max had statistical significance with correlation (R=0.53, 0.56, P<.01). Although both models are functional with validity considering their simplicity and utility, Model 2 has more accuracy.