• Journal of Life Science
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• v.13 no.1
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• pp.21-28
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• 2003

The purpose of this experiment was to compare the energy expenditure and the physiological response among two groups by percent body fat(group A: 30-35% body fat, B: 35-40% body fat) to walking and running at several equivalent speeds. Subjects in group A and B followed A group(mean$\pm$SD, age; 24.0$\pm$0.4yrs, body fat; 32.3$\pm$0.7) and B group (age; 25.2$\pm$0.7yrs, body fat; 36.7$\pm$0.9). The walking and running protocol consisted of treadmill speeds for five min at each of the following speeds: 5.0, 5.5, 6.0, 6.5, 7.0 km.$hr^{-1}$. The obtained data reveal in group A, the rate of oxygen consumption and energy expenditure was higher during walking compared to running ate treadmill speeds $\geq$ 6.6km.$hr^{-1}$. In group 5, the rate of oxygen consumption and energy expenditure was higher during walking compared to running ate treadmill speeds $\geq$ 6.8km.$hr^{-1}$. Heart rates and respiratory exchange ratio were higher at treadmill speeds $\geq$5.8 in group A and $\geq$5.5 in group B. these findings demonstrated that a difference of percent body fat in obese women have no large effect on energy efficiency of walking, but walking within speeds 6.5~7.0km/hr resulted in rates of energy expenditure that were as high or higher than jogging at the same speeds even though the relative stress was greater during walking.

• Weed & Turfgrass Science
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• v.2 no.4
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• pp.368-375
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• 2013

Whole genome transcriptomes from Miscanthus species were sequenced and analyzed, which provided 50 different types of transcription factor (TF) involving various developmental processes or environmental stresses. Among the explored TF, WRKY gene family was the major type and one of the WRKY genes, MSIR7180_WRKY4, induced under low temperature environment was selected to investigate how the Miscanthus-originated MSIR7180_WRKY4 TF responds when exposed to low temperature in four warm-season turfgrasses (Z. matrella 'Semil', bermudagrass, St. Augustinegrass, and seashore paspalum). The MSIR7180_WRKY4 was expressed higher during low temperature period in Bermudagrass, but the expression was enhanced in St. Augustinegrass. In contrast, the gene in 'Semil' cultivar was barely expressed and relatively less expressed, but repressed gradually in seashore paspalum, which seems to allow two turfgrasses stay-green longer in the fall season. The results indicate that bermudagrass and St. Augustinegrass adapt to low temperature quickly, but relative tolerance to low or cold temperature at the molecular level needs to be further investigated at different physiological stages and the corresponding genes systematically.

• Journal of Bio-Environment Control
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• v.29 no.3
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• pp.306-312
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• 2020

This study was conducted to investigate cucumber plants response to greenhouse environments by solar shading in greenhouse in the summer. In order to estimate heat stress reduction of cucumber plants by solar shading in greenhouse, we measured and analyzed physiological conditions of cucumber plants, such as leaf temperature, leaf-air temperature, rubisco maximum carboxylation rate, maximum electron transport rate, thermal breakdown, light leaf respiration, etc. Shading levels were 90% mobile shading of full sunlight, 40% mobile shading of full sunlight and no shading(full sunlight). The 90% shading screen was operated when the external solar radiation is greater than 650 W·m^-2. Air temperature, solar radiation, leaf temperature, leaf-air temperature and light leaf respiration in the 90% shading of full sunlight was lower than those of 40% shading and no shading. Rubisco maximum carboxylation rate, arrhenius function value and light leaf respiration of the 90% shading were significantly lower than those of 40% shading and no shading. The thermal breakdown, high temperature inhibition, of 90% shading was significantly higher than that of 40% shading and no shading. Therefore, these results suggest that 90% mobile shading made a less stressful growth environment for cucumber crops.

• Korean Journal of Weed Science
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• v.30 no.2
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• pp.111-121
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• 2010

Differential tolerance to protoporphyrinogen oxidase (Protox)-inhibiting herbicides, oxyfluorfen was observed between leaf ages in squash. Physiological responses to oxyfluorfen, including leaf injury, cellular leakage, accumulation of tetrapyrroles, and antioxidative enzymes activity, were investigated in leaf age classes of squash to identify mechanisms of oxyfluorfen tolerance. Leaf 1, 2, and 3 injuries for Joongangaehobak were >10,000, 1,286, and 1.6-fold higher than that of leaf 4, after treatment of oxyfluorfen. On the other hand, leaf 1, 2, and 3 injuries for Sintowjahobak were 725, 366, and >0.6-fold higher than that of leaf 4, after treatment of oxyfluorfen. However, in contrast to oxyfluorfen treatment results, leaf injury of squash leaf 4 treated with paraquat was much smaller than in leaves 1, 2 and 3. Electrolyte leakage from the tissues treated with oxyfluorfen was higher in the youngest leaf (Leaf 4) than in the older leaves 1, 2, and 3. Differential leaf response to oxyfluorfen of squash appears to be due in large part to differences in protoporphyrin IX (Proto IX), Mg-Proto IX, and Mg-Proto IX monomethyl ester accumulation in treated leaves. In contrast, leaf 4 had higher activities of superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, and glutathione reductase than leaf 1 after treatment with oxyfluorfen. However, the induction in antioxidant activity in leaf 4 was not enough to overcome the toxic effects of a Protox inhibitor, oxyfluorfen, so the leaf eventually died.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.419-425
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• 2004

Two different groups (30 and 60 inds.) of olive flounder (Paralichthys olivaceus) were abruptly (within 30 min) exposed to hypo-salinities from seawater (SW, 35$\textperthousand$) to freshwater (FW, 0$\textperthousand$) (30FW and 60FW) and to 35$\textperthousand$ (30SW and 60SW) in a flow through seawater culture systems. Analysis of plasma samples showed the following significant increase at 0$\textperthousand$: cortisol from $2.8\;ng\;mL^{-1}$ to $66.9\;ng\;mL^{-1}$ (30FW) and from $2.7\;ng\;mL^{-1}$ to $314.1\;ng\;mL^{-1}$ (60FW) after 24 hours of exposure; glucose from $15.8\;mg\;dL^{-1}$ to $257.7\;mg\;dL^{-1}$ after 3 hours exposure and to $164.0\;mg\;dL^{-1}$ after 24 hours in 60FW. Plasma $Na^+$ concentration of 30FW and 60FW were decreased until 24 hours after expose. However that in 30SW and 60SW showed no significant differences. Plasma $Cl^-$ concentration of 60FW was decreased from $59.0\;mEq\;L^{-1}$ to $43.5\;mEq\;L^{-1}$ and to $30.0\;mEq\;L^{-1}$ after 3 and 24 hours of exposure, respectively. At all experimental groups, survival were 100% until 24 hours.

• Journal of Life Science
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• v.32 no.2
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• pp.167-174
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• 2022

In modern society, interest in antioxidants is increasing as the stress caused by oxidants increases. However, the demand for synthetic antioxidants is decreasing because some studies have confirmed that they are harmful when consumed in large quantities; thus, studies on antioxidants derived from natural substances are actively being conducted to replace synthetic antioxidants. Blueberry, known as one of the world's top ten long-lived foods, is a plant of the Vaccinium (Ericaceae) family, and various pharmacological activities of blueberry including antioxidant activity have been studied. Vaccinium oldhamii (VO) is a deciduous broad-leaved shrub in the same genus as blueberries, and in this paper, we summarize the studies on the efficacy analysis of VO extracts and purified products. The content of phenolic compounds in VO fruits was proportional to antioxidant and anti-influenza activity such as the inhibition of NO production, and the total content of polyphenols and anthocyanin was higher than that in blueberries. VO fruit extracts showed anti-inflammatory activity and anti-cancer activity against human acute leukemia; in contrast, VO branch extracts showed anti-inflammatory activity, activity to inhibit osteoclast differentiation and bone resorption due to inflammatory response, and anti-cancer activity against several human cancer cell lines. Compared to blueberries, VO showed higher phenolic compound content, antioxidant activity, and various physiological activities. In addition, VO is considered to have sufficient value as an alternative crop to blueberries, such as it can be grown natively in Korea, with simple mass cultivation and no need to pay royalties for commercialization.

• Journal of Nutrition and Health
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• v.55 no.5
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• pp.523-532
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• 2022

Vitamin C is an important physiological antioxidant which neutralizes reactive oxygen species (ROS) and reduces the oxidative stress in the body. Although it has been associated with various diseases, few studies have reported the dose-response relationship between vitamin C intake, storage and functions in the body, including its antioxidant function. The criteria to establish the Dietary Reference Intakes for Koreans (KDRIs) for vitamin C were based on the changes in plasma concentrations and saturation of leukocytes according to intake levels and the effects on antioxidant capacity and risk of metabolic diseases. When establishing the 2020 vitamin C KDRI, while there was no change in the criteria from those of 2015, the reference values were recalculated and revised to reflect changes such as the new standard weight by age. As the number of people consuming dietary supplements has increased over the last decade, only about 10% of adults consume less than the average total vitamin C, but the proportion of adolescents and elderly who consume less than the average is high. On the other hand, as the intake of vitamin C supplements increases, the proportion of people consuming excessive vitamin C is also increasing. There is a body of opinion that it is necessary to establish a vitamin C KDRI for smokers or people with chronic diseases such as the metabolic syndrome, but these standards have not been established due to the lack of supporting scientific evidence. As a result, studies to establish vitamin C KDRI for Korean smokers and patients with the metabolic syndrome, as well as studies on the excessive intake of vitamin C due to supplementation and interactions with other nutrients, are needed.

• Science of Emotion and Sensibility
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• v.25 no.2
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• pp.79-86
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• 2022

With external air pollution forcing many people indoors, new methods of facilitating healthier indoor life are necessary. This study, therefore, investigates the effects of indoor oxygen concentration and respiration methods on biosignals and cognitive ability. The study included twenty healthy subjects who inhaled air through a mask from a gas delivery system. All subjects were asked to perform three types of breathing (nasal, oral, and oral breathing with high oxygenation) and respond to cognitive stimuli (rest close eye, rest open eye, 1-back and 2-back working memory tasks). The changes in cognitive load according to respiration were analyzed by measuring response time, accuracy, and biosignals to stimuli. The result showed that, in all three respirations, heart rate significantly increased with the increase in cognitive load. Also, in oral respiration, the airway respiration rate significantly increased according to the increase in cognitive load. The change appeared to compensate for insufficient oxygen supply in oral respiration during cognitive activity. Conversely, there was no significant change in airway respiration rate during oral respiration with a high concentration oxygen supply as in nasal respiration. This result suggests that a high concentration oxygen supply might play a role in compensating for insufficient oxygen concentration or inefficient oxygen inhalation, such as oral respiration. Based on the results of this study, a follow-up study is necessary to determine the impact of changes in the autonomic nervous system, such as stress and emotions, to find out more precise and comprehensive effects of oxygen concentration and breathing type.

• Biomolecules & Therapeutics
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• v.31 no.1
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• pp.73-81
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• 2023

Sirtuins (SIRTs) belong to the nicotinamide adenine dinucleotide (NAD+)-dependent class III histone deacetylase family. They are key regulators of cellular and physiological processes, such as cell survival, senescence, differentiation, DNA damage and stress response, cellular metabolism, and aging. SIRTs also influence carcinogenesis, making them potential targets for anticancer therapeutic strategies. In this study, we investigated the anticancer properties and underlying molecular mechanisms of a novel SIRT1 inhibitor, MHY2251, in human colorectal cancer (CRC) cells. MHY2251 reduced the viability of various human CRC cell lines, especially those with wild-type TP53. MHY2251 inhibited SIRT1 activity and SIRT1/2 protein expression, while promoting p53 acetylation, which is a target of SIRT1 in HCT116 cells. MHY2251 treatment triggered apoptosis in HCT116 cells. It increased the percentage of late apoptotic cells and the sub-G1 fraction (as detected by flow cytometric analysis) and induced DNA fragmentation. In addition, MHY2251 upregulated the expression of FasL and Fas, altered the ratio of Bax/Bcl-2, downregulated the levels of pro-caspase-8, -9, and -3 proteins, and induced subsequent poly(ADP-ribose) polymerase cleavage. The induction of apoptosis by MHY2251 was related to the activation of the caspase cascade, which was significantly attenuated by pre-treatment with Z-VAD-FMK, a pan-caspase inhibitor. Furthermore, MHY2251 stimulated the phosphorylation of c-Jun N-terminal kinase (JNK), and MHY2251-triggered apoptosis was blocked by pre-treatment with SP600125, a JNK inhibitor. This finding indicated the specific involvement of JNK in MHY2251-induced apoptosis. MHY2251 shows considerable potential as a therapeutic agent for targeting human CRC via the inhibition of SIRT1 and activation of JNK/p53 pathway.

• Journal of Marine Life Science
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• v.9 no.1
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• pp.22-32
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• 2024

The purpose of this study was to determine the effect of external biologger attachment methods on the blood parameters and attachment efficiency of spotted sea bass Lateolabrax maculatus (mean body weight 2630.8 g). The fish were tagged using four different external attachment methods with dummy biologgers: no attachment (control), anchor attachment (AA), monofilament attachment (MA), and silicon tube attachment (SA), each with triplicates. Blood indices and biologger attachment efficiency were assessed on days 1, 7, 14, 28, 56, and 84 after attachment. The concentrations of hematocrit, Na⁺, Cl^-, glutamic pyruvic transaminase and total protein, and the activity of superoxide dismutase in blood were not affected by the external attachment method of biologger. The concentrations of glutamic oxaloacetic transaminase (day 1 of attachment), hemoglobin (day 56) and total cholesterol (day 56 and 84) in AA group, the concentrations of glucose and cortisol (day 14) and total cholesterol (day 84) in MA group showed significantly higher than those of control (p<0.05). During the experiment period, the SA group had no differences from the control in all blood properties. The biologger attachment efficiencies of the AA, MA, and SA groups after 84 days were 0.0%, 33.3%, and 100.0%, respectively. These results indicate that the optimum external biologger attachment method under our experimental conditions is SA type.