• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.15-15
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• 2015

Aspergillus fumigatus is a major cause of invasive aspergillosis (IA), a significant health issue worldwide with high mortality rates up to 95%. Our lab is interested in how A. fumigatus adapts to low oxygen conditions 'hypoxia', which is one of the important host microenvironments. A. fumigatus SrbA is a basic helix-loop-helix (bHLH) transcriptional regulator and belongs to sterol regulatory element binding protein (SREBP) family members. Loss of SrbA completely blocks growth in hypoxia and results in avirulence in murine models of IA suggesting an essential role of SrbA in hypoxia adaptation and virulence in A. fumigatus. We conducted chromatin immunoprecipitation sequencing (ChIP-seq) with A. fumigatus wild type using a SrbA specific antibody, and 97 genes were revealed as SrbA direct targets. One of the 'SrbA regulons' (AFUB_099590) was a putative bHLH transcriptional regulator whose sequence contained a characteristic tyrosine substitution in the basic portion of the bHLH domain of SREBPs. Therefore, we designated AFUB_099590 SrbB. Further characterization of SrbB demonstrated that SrbB is important for radial growth, biomass production, and biosynthesis of heme intermediates in hypoxia and virulence in A. fumigatus. A series of quantitative real time PCR showed that transcription of several SrbA regulons is coordinately regulated by two SREBPs, SrbA and SrbB in hypoxia. This suggests that SrbA and SrbB have both dependent and independent functions in regulation of genes responsible for hypoxia adaptation in A. fumigatus. Together, our data provide new insights into complicated roles of SREBPs in adaptation of host environments and virulence in pathogenic fungi.

• Archives of Plastic Surgery
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• v.37 no.5
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• pp.600-606
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• 2010

Purpose: Although traditional and current treatment strategies may demonstrate success, persistence or recurrence of difficult-to-heal wounds remain significant problems. A novel product, Hyalomatrix$^{(R)}$ (Fidia Advanced Biopolymer, Abano Terme, Italy) is a bilayer of an benzyl esterified hyaluronan scaffold beneath a silicone membrane. The scaffold delivers hyaluronan to the wound, and the silicone membrane acts as a temporary epidermal barrier. We present the results obtained with Hyalomatrix$^{(R)}$ in the treatment of difficult-to-heal wounds. Methods: From November, 2008 to March, 2010, Hyalomatrix$^{(R)}$ has been used on total 10 patients with wounds that were expected difficult to heal with traditional and other current strategies. After average 37.4 days from development of wounds, Hyalomatrix$^{(R)}$ was applied after wound debridement. On the average, Hyalomatrix$^{(R)}$ application period was 17.6 days. After average 16.5 days from removal of Hyalomatrix$^{(R)}$, skin grafts was performed. Results: In all cases, regeneration of fibrous granulation tissues and edge re-epithelization were present after the application of the Hyalomatrix$^{(R)}$. And all of the previous inflammatory signs were reduced. After skin grafts, no adverse reactions were recorded in 9 cases. But in one case, postoperative wound infection occured due to a lack of efficient fibrous tissues. In this model, the Hyalomatrix$^{(R)}$ acts as a hyaluronan delivery system and a barrier from the external environments. In tissue repair processes, the hyaluronan performs to facilitate the entry of a large number of cells into the wounds, to orientate the deposition of extracellular matrix fibrous components and to change the microenvironment of difficult-to-heal wounds. Conclusion: Our study suggests that Hyalomatrix$^{(R)}$ could be a good and feasible approach for difficult-to-heal wounds. The Hyalomatrix$^{(R)}$ improves microenvironments of difficult-to-heal wounds, reduces infection rates and physical stimulus despite of aggravating factors.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.304-304
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• 2017

In semi-arid countries such as Namibia, the flooding unexpectedly happens in a rainy season, causing losses in the yield of upland-adapted cereal crop. In flooding conditions, rice roots sequentially form aerenchyma and a barrier to radial oxygen loss (ROL), and oxygen is released into the rhizosphere near the root tips. Iijima et al. (2016) and Awala et al. (2016) reported that close mixed-planting with rice can mitigate the flood stress of co-growing upland-adapted cereal crop by modifying their rhizosphere microenvironments via the oxygen released from the rice roots. Moreover, by using the model system of hydroponic culture, it was confirmed that oxygen from rice roots was transferred to co-growing upland-adapted cereal crop in close mixed planting system (Kawato et al., 2016). However, it is not sure whether the ability of oxygen release varies among rice cultivars, because Kawato et al. (2016) used only one japonica cultivar, Nipponbare (Oryza sativa). The objective of this study was to compare the ability of oxygen release in rhizosphere among rice cultivars. The experiment was conducted in a climate chamber in Kindai University. We used 10 rice cultivars from three different rice species (O. sativa (var. japonica (2), var. indica (3)), Oryza glaberrima Steud. (2) and their interspecific progenies (3)) to compare the ability of oxygen release from the roots. According to the method by Kawato et al. (2016), the dissolved oxygen concentration of phase I (with shoot) and phase II (without shoot) were measured by a fiber optic oxygen-sensing probe. The oxygen released from rice roots was calculated from the difference of the measurements between phase I and phase II. The result in this study indicated that all of the rice cultivars released oxygen from their roots, and the amount of released oxygen was significantly correlated with the above-ground biomass (r = 0.710). The ability of oxygen release (the amount of the oxygen release per fresh root weight) of indica cultivars (O. sativa) tended to be higher as compared with the other cultivars. On the other hand, that of African rice (O. glaberrima) and the interspecific progenies tended to be lower. These results suggested that the ability of oxygen release widely varies among rice cultivars, and some of indica cultivars (O. sativa) may be suitable for close mixed-planting to mitigate flood stress of upland-adapted cereal crop.

• Journal of Life Science
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• v.23 no.2
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• pp.324-331
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• 2013

The addition and removal of N-acetylglucosamine (GlcNAc) molecules on serine or threonine residues of a protein is called O-GlcNAcylation. This post-translational modification occurs on both cytoplasmic and nuclear protein, and is fast and reversible as comparable to phosphorylation. In contrast to the phospho-signaling cycles, this emerging moon-lightening signaling is cycled by only two enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). The simple machinery is a good evolutionary adaptation of a cell for quick accommodation to continuously fluctuating intra- and extracellular microenvironments. Rather than "switching" on or off a specific proteins - this would be done by phosphorylation where numerous specific kinases and phosphatases are involved - O-GlcNAcylation would play a "rheostat" which would be much more delicately increase or decrease the efficacy of signal transductions in response to cellular nutrient and stress conditions. Interestingly, recent evidence indicates that O-GlcNAc is further modified by phosphorylation. The O-GlcNAc-P will upgrade the modulation efficiency of cellular processes to continuous 'analogue' level. So far, only one protein AP180 was reported to have O-GlcNAc-P on Thr310. But, proteomic data from our laboratory indicate that there are multiple O-GlcNAc-P proteins, constituting "O-GlcNAc-P'om". This will focus on the possibility of existence of "O-GlcNAc-P'om".

• Journal of Environmental Health Sciences
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• v.45 no.3
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• pp.247-257
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• 2019

Objectives: The Korea Ministry of Environment regulates concentrations of hazardous air pollutants (HAPs) through Atmosphere Environmental Standards to protect public health from HAPs. However, simply determining the exceedance of HAP concentrations has several limitations and more comprehensive assessment is required. In addition, integrated risk assessment is needed considering exposure in all microenvironments, including outdoor as well as indoor environments. The purpose of this study was to assess the differences in risk by sub-population groups according to time-activity patterns and reported concentrations, as well as the lifetime risk for Koreans. Methods: In this study, we calculated time-weighted average exposure concentrations for benzene and $PM_{10}$ among preschool-age children, students, housewifes, workers, and the elderly using residential time and concentrations for indoor (house, school or workplace, other), outdoor, and transport by the meta-analysis method. The risk assessments were conducted by excess cancer risk and disease death risk using 1,000,000 Monte-Carlo simulations for probabilistic analysis. Results: Preschool-age children, students, housewifes, workers, and the elderly spent 91.9, 86.0, 79.8, 82.2, and 77.3% of their day in their house, workplace, or school, respectively. The more than 99% excess cancer risk for benzene exceed 1.0E-06 in all sub-populations and lifetime. The acute disease death risk for $PM_{10}$ for housewifes and workers for lifetime were 3.35E-04 and 3.18E-04, and chronic disease death risks were 2.84E-03 and 2.70E-03, respectively. Conclusions: The risk of benzene and $PM_{10}$ by sub-population group and for the lifetime of housewifes and workers were assessed. Benzene showed risky results for this study. All disease death risks of $PM_{10}$ were higher than 1.0E-04 and showed different risks by sub-population. This study can be used as a basis for lifetime exposure and risk assessment to benzene and $PM_{10}$.

• Journal of Environmental Health Sciences
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• v.45 no.2
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• pp.113-125
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• 2019

Objectives: Although the risk assessments for nitrogen dioxide ($NO_2$) and ozone ($O_3$) have been extensively studied, most of the existing risk assessments were limited mainly to indoor environments such as workplaces, schools, and multi-use facilities. Therefore, integrated risk assessment is needed to consider exposure in all microenvironments, including outdoors. The purpose of this study was to assess the differences in risk among sub-population groups according to time-activity patterns and reported concentrations, as well as the lifetime risk of Koreans. Methods: In this study, we estimated time-weighted average exposure concentrations of $NO_2$ and $O_3$ for preschool children, students, housewives, workers, and seniors using residential time and indoor concentrations (house, school or workplace, other), outdoors, and transport by meta-analysis method. The risk for $NO_2$ and $O_3$ were assessed by hazard quotient using reference concentrations 30 and 60 ppb, respectively. The risk assessments were conducted through 1,000,000 Monte-Carlo simulations for probabilistic analysis. Results: Preschool children, students, housewives, workers, and seniors spent 91.9, 86.0, 79.8, 82.2, and 77.3% of their day in a house, school, or workplace, respectively. The risk assessment for the lifetime of a housewife and a worker showed that 33.8 and 28.4% of hazard quotients of $NO_2$ exceed 1, respectively, and more than 99% of hazard quotient of $O_3$ were less than 1. Conclusions: The risk of $NO_2$ and $O_3$ by sub-population group and for the lifetime of housewives and workers were assessed. The risk for $NO_2$ was higher than for $O_3$ and showed a different risk by sub-population group. Both $NO_2$ and $O_3$ showed a higher risk for housewives than for workers. This study can be used as a basis for lifetime exposure and risk assessment for $NO_2$ and $O_3$.

• Particle and aerosol research
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• v.14 no.4
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• pp.97-105
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• 2018

Recently, people's interest in particulate matter (PM) has been increasing, due to its hazardous health effects. The purpose of this study was to investigate the concentrations and as well as the inhaled weight of PM, correlated with person's heart rate in subway, bus, vehicle and bicycle in the major public transportation (Sadang - Jamsil and Nowon - Dongdaemun) in Seoul. The concentration of $PM_{10}$ and $PM_{2.5}$ were measured from each of transportation means and calculated the average concentrations which were 87.2 and $57.8{\mu}g/m^3$ for subway, 62.8 and $42.5{\mu}g/m^3$ for vehicle, 61.5 and $36.8{\mu}g/m^3$ for bus and 53.0 and $29.4{\mu}g/m^3$ for bicycle in $PM_{10}$ and $PM_{2.5}$ respectively. Inhalation dose for $PM_{10}$ and $PM_{2.5}$ were estimated at 248.1 and $139.4{\mu}g$ for bicycle, 56.7 and $39.3{\mu}g$ for vehicle, 49.4 and $29.9{\mu}g$ for bus and 44.3 and $29.1{\mu}g$ for subway, respectively. Even though subway had the highest concentration, the highest inhalation dose was the bicycle. It was due to the long travel time-exposure and breathing rate which leads to maximum of $PM_{10}$ 5.6 and $PM_{2.5}$ with 4.8 times inhalation dose comparing with other modes of transportation. With regards to future studies, the amount of inhalation in each transportation means should be considered in risk assessments of PM.

• Korean Journal of Environment and Ecology
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• v.35 no.1
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• pp.37-47
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• 2021

This study carried out the plant sociological survey of Abies nephrolepis forest in Mt. Seorak, which is in danger of deterioration due to the accelerated climate change. We examined seventy quadrats obtained from the survey and used the TWINSPAN technique to classify communities. We then performed the DCA method for the sequence analysis and analyzed the characteristics of each community. A. nephrolepis forest of Mt. Seorak is composed of four communities (A. nephrolepis-Lonicera caerulea var. edulis community, A. nephrolepis-Acer komarovii community, A. nephrolepis-Ac. pseudosieboldianum community, and A. nephrolepis-Betula costata community). Each community showed a different distribution according to location because different microenvironments are formed depending on location such as altitude and slope direction, resulting in different species composition. Each community showed differences in environmental characteristics such as altitude, rock ratio, soil characteristics, and litter layer thickness. As a result, there were significant differences between communities in the number of species and individuals, coverage, tree size, and species diversity, as well as differences in species composition. The A. nephrolepis-L. caerulea var. edulis and A. nephrolepis-Ac. komarovii communities were located in high altitude with high rock ratios and had little development of tree layer. On the other hand, the A. nephrolepis-Ac. pseudosieboldianum and A. nephrolepis-B. costata communities were relatively in low altitude with high soil ratio and had the development of tree layer with high species diversity.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.11
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• pp.812-820
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• 2011

This study was conducted to characterize $CO_2$ biomineralization on several minerals (i.e., CaO, MgO, $SiO_2$) by bottle test in an aqueous solution and solidified sludge using different aerobic bacterial strains like Bacillus megaterium and Bacillus pasteurii by batch test. These bacteria promote the formation of microenvironments that facilitate the precipitation of mineral phases that were unsaturated in the bulk solution. For one type of mineral solely amended, the $CO_2$ was reduced at the highest of 4.0 mmol for MgO while it was not that much lower for CaO and $SiO_2$ showing 1.1 and 0.3 mmol $CO_2$2, respectively. For two types of minerals simultaneously amended, the $CO_2$ was reduced at the greater extent for both Ca + Mg and Mg + Si showing 2.7 and 2.3 mmol, respectively whereas it was less for Ca + Si at 1.8 mmol. For solidified sludge, the $CO_2$ reduction rate changed depending on the volume of solidified sludge placed in the medium and the input $CO_2$ concentration.. The reduction rate of $CO_2$ was increased with increasing the volume of solidified sludge. Results of XRD analysis indicate that $CaCO_3$ (Calcite) was dominantly formed among others (e.g., Aragonite, Dolomite). SEM analysis showed that the sample with Bacillus pasteurii, could more form minerals rather than control. As demonstrated in this study, $CO_2$ would be effectively sequestered in biomineralization process.