• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.63.2-63.2
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• 2008

• Korean Journal of Exercise Nutrition
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• v.24 no.1
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• pp.19-23
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• 2020

[Purpose] Blood glucose and insulin resistance were lower following hypoxic exposure in previous studies. However, the effect of hypoxia as therapy in obese model has not been unknown. [Methods] Six-week-old mice were randomly divided into chow diet (n=10) and high-fat diet (HFD) groups (n=20). The chow diet group received a non-purified commercial diet (65 % carbohydrate, 21 % protein, and 14 % fat) and water ad libitum. The HFD group was fed an HFD (Research Diet, #D12492; 60% kcal from fat, 5.24 kcal/g). Both groups consumed their respective diet for 7 weeks. Subsequently, HFD-induced mice (12-weeks-old) were randomly divided into two treatment groups : HFD-Normoxia (HFD; n=10) and HFD-Hypoxia (HYP; n=10, fraction of inspired=14.6%). After treatment for 4 weeks, serum glucose, insulin and oral glucose tolerance tests (OGTT) were performed. [Results] Homeostatic model assessment values for insulin resistance (HOMA-IR) of the HYP group tended to be lower than the HFD group. Regarding the OGTT, the area under the curve was 13% lower for the HYP group than the HFD group. [Conclusion] Insulin resistance tended to be lower and glucose uptake capacity was significantly augmented under hypoxia. From a clinical perspective, exposure to hypoxia may be a practical method of treating obesity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.400-405
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• 2005

Wet-injury often occurs in upland cereals growing in the paddy field due to oxygen deficiency in the rhizosphere caused by excessive water in the soil. Under hypoxia, energy metabolism is diminished causing non­reversible damage to root cells. This study was conducted to investigate effects of hypoxia on root growth and enzymes involved in the fermentative energy metabolism in upland cereals including barley, wheat, rye and triticale. Young seedlings were subject to hypoxia for up to 7 days. Root fresh weight and dry weight were decreased significantly by hypoxia for 5 to 7 days in all cereal seedlings. Root growth retardation under hypoxia was lowest in barley. Hypoxia-induced increases in activity and isozyme expression of alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH) were commonly observed in roots of all cereal seedlings. The inherent ADH activity levels were higher in barley but the hypoxia-induced increases in ADH activities were lowest in barley than other cereals. The inherent LDH activity levels were lower in barley and the hypoxia-induced increases in LDH activities were lower in barley than other cereals. The results suggest the importance of the rapid enhancement of fermentative enzyme systems for increased tolerance to hypoxia.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.4
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• pp.1082-1091
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• 2003

To elucidate the neuroprotective effect of Kamijihwang-hwan(KSH) on nerve cells damaged by hypoxia, the cytotoxic effects of exposure to hypoxia were determined by XTT, NR, MTT and SRB asssay. The activity of catalase and SOD was measured by spectrophometry, and TNF-α and PKC activity was measured after exposure to hypoxia and treatment of Kamijihwang-hwan(KSH) water extract(KJHWE). Also the neuroprotective effect of KJHWE was researched for the elucidation of neuroprotective mechanism. The results were as follows ; Hypoxia decreased cell viability measured by XTT, NR assay when cultured cerebral neurons were exposed to 95% N2/5% CO₂ for 2～26 minutes in these cultures and KJHWE inhibited the decrease of cell viability. H₂O₂ treatment decreased cell viability measured by MTT, and SRB assay when cultured cerebral neurons were exposed to 1-80 uM for 6 hours, but KJHWE inhibited the decrease of cell viability. Hypoxia decreased catalase and SOD activity, and also TNF-α and PKC activity in these cultured cerebral neurons, but KJHWE inhibited the decrease of the catalase and SOD activity in these cultures. Hypoxia triggered the apoptosis via caspase activation and internucleosomal DNA fragmentation. Also hypoxia stimulate the release of cytochrome c form mitochondria. KJHWE inhibited the apoptosis via caspase activation induced by hypoxia. From these results, it can be suggested that brain ischemia model induced hypoxia showed neurotoxity on cultured mouse cerebral neurons, and the KJHWE has the neuroprotective effect in blocking the neurotoxity induced by hypoxia in cultured mouse cerebral neurons.

• Biomolecules & Therapeutics
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• v.16 no.4
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• pp.377-384
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• 2008

Chungpesagan-tang (CST) has been traditionally used in Korea as a therapeutic for cerebral ischemia. To understand the protective mechanism of CST on hypoxia/reoxygenation insults in N2a cells, the cell viability was determined with the treatment of water solution and several solvent fractions of CST. The highest cell viability occurred when the cells were treated with the hexane soluble fraction of CST. Hypoxia/reoxygenation insults were shown to decrease the glutathione peroxidase (GPx) activity and the level of glutathione (GSH) and increase the superoxide dismutase (SOD) activity. However, treatment with hexane soluble fraction of CST ranging from 0.1 ${\mu}g$/ml to 10 ${\mu}g$/ml recovered the activities of GPx and SOD and maintained the levels of MDA and GSH at control levels. While hypoxia/reoxygenation insults induced the activation of ERK in N2a cells, treatment with the hexane soluble fraction of CST inhibited the activation of ERK in a concentration dependent manner. In this study, we were able to demonstrate that the bioactive compounds of CST can be effectively transferred into the hexane soluble fraction, and more importantly that CST exhibits protective effects against hypoxia/reoxygenation insults most likely by recovering redox enzyme activities.

• Journal of Life Science
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• v.17 no.5 s.85
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• pp.706-713
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• 2007

Scutellaria baicalensis GEORGI(SB) is used in oriental medicine for the treatment of incipient strokes. Although it has been reported that SB is neuroprotective in a hypoxia model, its mechanism is poorly understood. Here, we investigated the effect of SB on the modulation of heme oxygenase-1(HO-1), which has important biological roles in regulating mitochondrial heme protein turnover and in protecting against conditions such as hypoxia, neurodegenerative diseases, or sepsis. Rat cerebrocortical day In vitro(DIV)12 cells were grown in neurobasal medium. On DIV12 cells were treated with SB($20{\mu}g/ml$) and given a hypoxic shock ($2%\;O_2/5%\;CO_2,\;3\;hr$) on DIV14. In situ hybridization results revealed that SB upregulated HO-1 mRNA in neuronal dendrites in both normoxia and hypoxia(38.5% and 59.2%, respectively). At the protein level, SB upregulated HO-1 in the neuronal soma in both normoxia and hypoxia(22.4% and 15.7%, respectively). Interestingly, most significant increase was associated with astrocytes, which increased HO-1 protein by 77.5% compared to SB-untreated culture. These results indicate that SB upregulates both neuronal and glial HO-1 expression, which contributes to the neuroprotection efficacy in hypoxia).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.3
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• pp.172-183
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• 2005

To assess the macrobenthic community of oligohaline Youngam Lake, which is located at the Youngsan Watershed on the southwest part of Korea, macrobenthic fauna were collected at 45 stations during May, 2002. A total of 16 species of macrofauna were recorded with a mean density of 240 individuals per $m^2$ and a mean biomass of 7.07 g wet weight per $m^2$. Major dominant faunal groups were crustacean arthropods in terms of the number of species and abundance, and polychaete annelids in terms of biomass. The mean grain size was $5.7\;{\phi}$ which was dominated by silt fraction. The hydrological environment of the lake was characterised as an oligohaline environment with a mean surface water temperature of $17.8^{\circ}C$ and a mean salinity of 2.08 psu. The major dominant species were amphipods, Corophium sp. ($31\%$) and Jesogammarus sp. ($25\%$). Lowe. values of species diversity (H') with a mean of 0.81 (less than 1.0 from most stations) reflected the overall poor faunal diversity in this area. Multivariate analysis suggested that this benthic faunal community could be divided into four sub-regions such as the area from lake proper to water channel to the south, the stations located at the entrance and northern water channel, the stations near the dike, and the lake proper area. Freshwater and brackish water species which occurred in each station group were corresponded to the oligohaline salinity regime. Bottom hypoxia appeared in the entrance part of the lake between dyke and lake proper on May, which was resulted from stratification from spring season. These facts imply that marine macrobenthos were severely impacted by low salinity and a consequent hypoxia after embankment of the lake due to the restriction of water circulation.

• Journal of Life Science
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• v.19 no.5
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• pp.598-606
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• 2009

Oxidative stress by free radicals is a major cause of neuronal cell death. Excitotoxicity in hypoxia/ischemia causes an increase in reactive oxygen species (ROS) and a loss of mitochondrial membrane potential (MMP), resulting in dysfunction of the mitochondria and cell death. Pinelliae Rhizoma (PR) is a traditional medicine for incipient stroke. We investigated the effects of PR Water-Extract on the modulation of ROS and MMP in a hypoxic model using cultured rat cortical cells. PR Water-Extract was added to the culture medium at various concentrations (0.25${\sim}$5, 5.0 ${\mu}g/ml$) on day in vitro 12(DIV12), given a hypoxic shock (2% $O_2$/5% $CO_2$, $37^{\circ}C$, 3 hr), and cell viability was assessed on DIV15 by Lactate Dehydrogenase Assay (LDH assays). PR Water-Extract showed a statistically significant effect on neuroprotection (10${\sim}$15% increase in viability; p<0.01) at 1.0 and 2.5 ${\mu}g/ml$ in normoxia and hypoxia. Measurement of ROS production by $H_2DCF-DA$ stainings showed that PR Water-Extract efficiently reduced the number and intensity of ROS-producing neurons, especially at 1 hr post shock and DIV15. When MMP was measured by JC-1 stainings, PR Water-Extract efficiently maintained high-energy charged mitochondria. These results indicate that PR Water-Extract protects neurons in hypoxia by preventing ROS production and preserving the cellular energy level.

• The Journal of Internal Korean Medicine
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• v.30 no.1
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• pp.24-35
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• 2009

Object : In conditions of brain infarction, irreversible axon damage occurs in the central nerve system (CNS), because gliosis makes physical and mechanical barriers. If gliosis formation could be suppressed, irreversible axon damage would be reduced. This could mean that an injured CNS could be regenerated. CD81 and GFAP have close relationships to gliosis. The increase in glial cells at CNS injury gives rise to the expression of CD81 and GFAP. CD81 was postulated to play a central role in the process of CNS scar formation. Method : In this study, the author investigated the effect of the water extract of the Moutan Radicis Cortex on regulation of CD81 and GFAP expression in injured CNS cells. MTT assay was used to examine cell viability, while RT-PCR and ELISA methods were carried out to measure the expression of CD81 and GFAP in the astrocyte. Results : We observed that water extract of the Moutan Radicis Cortex increased cell viability under hypoxia induced by $CoCl_2$ and suppressed the expression of CD81 and GFAP up-regulated by hypoxia. Conclusion : These results suggest that the Moutan Redicis Cortex could promote neural regeneration as a consequence of protecting CNS cells from hypoxia and suppressing the reactive gliosis following CNS injury.

• ALGAE
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• v.38 no.4
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• pp.265-281
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• 2023

Hypoxia can indeed impact the survival of protists, which play a crucial role in marine ecosystems. To better understand the protistan community structure and species that can thrive in hypoxic waters, we collected samples from both the surface and bottom waters during the hypoxic period in Jinhae and Masan Bays and the non-hypoxic period in Jinhae Bay. Subsequently, we utilized metabarcoding techniques to identify the protistan species. During hypoxia, with dissolved oxygen concentrations of 0.8 mg L^-1 in Jinhae Bay and 1.8 mg L^-1 in Masan Bay within the bottom waters, the phylum Dinoflagellata exhibited the highest amplicon sequence variants richness among the identified protist phyla. Following the Dinoflagellata, Ochrophyta and Ciliophora also displayed notable presence. In hypoxic waters of Jinhae and Masan Bays, we identified a total of 36 dinoflagellate species that exhibited various trophic modes. These included one autotrophic species, 14 mixotrophic species, 9 phototrophic species with undetermined trophic modes (either autotrophic or mixotrophic), 2 kleptoplastidic species, and 10 heterotrophic species. Furthermore, the hypoxic bottom water exhibited a greater number of heterotrophic dinoflagellate species compared to the non-hypoxic surface water within the same water column or the non-hypoxic bottom water. Therefore, feeding by mixotrophic and heterotrophic dinoflagellates may be partially responsible for their dominance in terms of the number of species surviving in hypoxic waters. This study not only introduces the initial documentation of 26 dinoflagellate species surviving in hypoxic conditions but also establishes a foundation for a more comprehensive understanding of the ecophysiology of dinoflagellates in hypoxic marine environments.