• Korean Journal of Microbiology
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• v.44 no.2
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• pp.147-155
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• 2008

The diversity of sulfate reducing bacteria was investigated in different depths of sediments in Lake Sihwa, Korea and Lake Aha, China by PCR amplification, denaturing gradient gel electrophoresis (DGGE) and clone libraries targeting dissimilatory sulfite redectase (dsr) gene. In the analysis of DGGE band patterns, the community compositions of dsr gene in the sediments of both lakes were significantly different whereas bands in all depths of each environment revealed similar patterns. Bands from Lake Sihwa were produced much more than those from Lake Aha, demonstrating a higher diversity of dsr gene in Lake Sihwa. Total 68 clones containing dsr gene were obtained to analyze their sequences. Sequences from the sediment of Lake Sihwa were affiliated to Deltaproteobacteria, the Gram-positive thermophilic sulfate reducers belonging to the genus Desulforomaculum and archaeal thermophilic SRB belonging to the genus Archaeoglobus, whereas sequences from the sediments of Lake Aha were related to genus Desulfotomaculum. Clones retrieved from sediment of Lake Sihwa revealed a higher numbers than those of Lake Aha, demonstrating a higher diversity of dsr gene in Lake Sihwa. Most of clones (59%) were distantly related to the known cultivated SRB with $60\sim65%$ of similarity, which were clustered only the sequences from the environments showed less than 90% similarity. These habitat specific sequences suggested that the clustered dsr sequences represent species or groups of species that were indigenous to these environments. This study showed that these lakes have a specific bacterial communities having dsr gene distinct from those in other environments such as soil and marine ecosystems around the world.

• The Korean Journal of Physiology and Pharmacology
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• v.19 no.4
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• pp.309-318
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• 2015

Alcohol consumption increases the risk of type 2 diabetes. However, its effects on prediabetes or early diabetes have not been studied. We investigated endoplasmic reticulum (ER) stress in the pancreas and liver resulting from chronic alcohol consumption in the prediabetes and early stages of diabetes. We separated Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a type-2 diabetic animal model, into two groups based on diabetic stage: prediabetes and early diabetes were defined as occurrence between the ages of 11 to 16 weeks and 17 to 22 weeks, respectively. The experimental group received an ethanol-containing liquid diet for 6 weeks. An intraperitoneal glucose tolerance test was conducted after 16 and 22 weeks for the prediabetic and early diabetes groups, respectively. There were no significant differences in body weight between the control and ethanol groups. Fasting and 120-min glucose levels were lower and higher, respectively, in the ethanol group than in the control group. In prediabetes rats, alcohol induced significant expression of ER stress markers in the pancreas; however, alcohol did not affect the liver. In early diabetes rats, alcohol significantly increased most ER stress-marker levels in both the pancreas and liver. These results indicate that chronic alcohol consumption increased the risk of diabetes in prediabetic and early diabetic OLETF rats; the pancreas was more susceptible to damage than was the liver in the early diabetic stages, and the adaptive and proapoptotic pathway of ER stress may play key roles in the development and progression of diabetes affected by chronic alcohol ingestion.

• Korean Journal of Remote Sensing
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• v.30 no.5
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• pp.627-639
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• 2014

Accurate correction of surface effect from back scattered solar radiance is one of key issue to retrieve aerosol information from satellite measurements. In this study, two different methods are applied to retrieve surface reflectance by using single visible channel measurement from meteorological imager onboard COMS. The first one is minimum reflectance method, which composes the minimum value among previously measured reflectances at each pixel over a certain search window length. This method assumes that the darkest pixel corresponds to the aerosol-free condition, and deduces surface reflectance by correcting atmospheric scattering from the measured visible reflectance. The second method, named as the "atmospheric correction method" in this study, estimates the result by correcting aerosol and atmospheric scattering with ground-based observation of aerosol optical properties. The purpose of this study is to investigate the retrieval accuracy of the widelyused minimum reflectance method. Also, the retrieval error caused by the loading of background aerosol is mainly estimated. The comparison between surface reflectances retrieved from the two methods shows good agreement with the correlation coefficient of 0.87. However, the results from the minimum reflectance method are slightly overestimated than the values from the atmospheric correction method when surface reflectance is lower than 0.2. The average difference between the two results is 0.012 without the background aerosol correction. By considering the background aerosol effect, however, the difference is reduced to 0.010.

• Molecules and Cells
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• v.28 no.5
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• pp.431-439
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• 2009

Rice Oryza sativa accelerated cell death and resistance 1 (OsACDR1) encodes a putative Raf-like mitogen-activated protein kinase kinase kinase (MAPKKK). We had previously reported upregulation of the OsACDR1 transcript by a range of environmental stimuli involved in eliciting defense-related pathways. Here we apply biochemical, gain and loss-of-function approaches to characterize OsACDR1 function in rice. The OsACDR1 protein showed autophosphorylation and possessed kinase activity. Rice plants overexpressing OsACDR1 exhibited spontaneous hypersensitive response (HR)-like lesions on leaves, upregulation of defense-related marker genes and accumulation of phenolic compounds and secondary metabolites (phytoalexins). These transgenic plants also acquired enhanced resistance to a fungal pathogen (Magnaporthe grisea) and showed inhibition of appressorial penetration on the leaf surface. In contrast, loss-of-function and RNA silenced OsACDR1 rice mutant plants showed downregulation of defense-related marker genes expressions and susceptibility to M. grisea. Furthermore, transient expression of an OsACDR1:GFP fusion protein in rice protoplast and onion epidermal cells revealed its localization to the nucleus. These results indicate that OsACDR1 plays an important role in the positive regulation of disease resistance in rice.

• Journal of Ecology and Environment
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• v.45 no.3
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• pp.143-151
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• 2021

Background: Plants are able to optimize defense responses induced by various herbivores, which have different feeding strategies. Local and systemic responses within a plant after herbivory are essential to modulate herbivore-specific plant responses. For instance, leaf-chewing herbivores elicit jasmonic acid signaling, which result in the inductions of toxic chemicals in the attacked leaf (tissue-specific responses) and also in the other unattacked parts of the plant (systemic responses). Root herbivory induces toxic metabolites in the attacked root and alters the levels of transcripts and metabolites in the unattacked shoot. However, we have little knowledge of the local and systemic responses against stem-boring herbivores. In this study, we examined the systemic changes in metabolites in the wild tobacco Nicotiana attenuata, when the stem-boring herbivore Trichobaris mucorea attacks. Results: To investigate the systemic responses of T. mucorea attacks, we measured the levels of jasmonic acid (JA), JA-dependent secondary metabolites, soluble sugars, and free amino acids in 7 distinct tissues of N. attenuata: leaf lamina with epidermis (LLE), leaf midrib (LM), stem epidermis (SE), stem pith (SP), stem vascular bundle (SV), root cortex with epidermis (RCE), and root vascular bundle (RV). The levels of JA were increased in all root tissues and in LM by T. mucorea attacks. The levels of chlorogenic acids (CGAs) and nicotine were increased in all stem tissues by T. mucorea. However, CGA was systematically induced in LM, and nicotine was systematically induced in LM and RCE. We further tested the resource allocation by measuring soluble sugars and free amino acids in plant tissues. T. mucorea attacks increased the level of free amino acids in all tissues except in LLE. The levels of soluble sugars were significantly decreased in SE and SP, but increased in RV. Conclusions: The results reveal that plants have local- and systemic-specific responses in response to attack from a stem-boring herbivore. Interestingly, the level of induced secondary metabolites was not consistent with the systemic inductions of JA. Spatiotemporal resolution of plant defense responses against stem herbivory will be required to understand how a plant copes with attack from herbivores from different feeding guilds.

• Journal of The Korean Astronomical Society
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• v.55 no.5
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• pp.173-194
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• 2022

We complete the survey for finite-source/point-lens (FSPL) giant-source events in 2016-2019 KMTNet microlensing data. The 30 FSPL events show a clear gap in Einstein radius, 9 𝜇as < 𝜃_E < 26 𝜇as, which is consistent with the gap in Einstein timescales near t_E ~ 0.5 days found by Mróz et al. (2017) in an independent sample of point-source/point-lens (PSPL) events. We demonstrate that the two surveys are consistent. We estimate that the 4 events below this gap are due to a power-law distribution of free-floating planet candidates (FFPs) dN_FFP/d log M = (0.4 ± 0.2) (M/38 M_⊕)^-p/star, with 0.9 ≲ p ≲ 1.2. There are substantially more FFPs than known bound planets, implying that the bound planet power-law index 𝛾 = 0.6 is likely shaped by the ejection process at least as much as by formation. The mass density per decade of FFPs in the Solar neighborhood is of the same order as that of 'Oumuamua-like objects. In particular, if we assume that 'Oumuamua is part of the same process that ejected the FFPs to very wide or unbound orbits, the power-law index is p = 0.89 ± 0.06. If the Solar System's endowment of Neptune-mass objects in Neptune-like orbits is typical, which is consistent with the results of Poleski et al. (2021), then these could account for a substantial fraction of the FFPs in the Neptune-mass range.

• Atmosphere
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• v.32 no.2
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• pp.103-118
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• 2022

This study evaluates the simulated meteorological fields with a particular focus on the low-level wind, which plays an important role in air pollutants dispersion, under the varying synoptic environment. Additionally, the effects of subgrid-scale orography parameterization and improved topography/land-use data on the simulated low-level wind is investigated. The WRF model version 4.1.3 is utilized to simulate two cases that were affected by different synoptic environments. One case from 2 to 6 April 2012 presents the substantial low-level wind speed over the Korean peninsula where the synoptic environment is characterized by the baroclinic instability. The other case from 14 to 18 April 2012 presents the relatively weak low-level wind speed and distinct diurnal cycle of low-level meteorological fields. The control simulations of both cases represent the systematic overestimation of the low-level wind speed. The positive bias for the case under the baroclinic instability is considerably alleviated by applying the subgrid-scale orography parameterization. However, the improvement of wind speed for the other case showing relatively weak low-level wind speed is not significant. Applying the high-resolution topography and land-use data also improves the simulated wind speed by reducing the positive bias. Our analysis shows that the increased roughness length in the high-resolution topography and land-use data is the key contributor that reduces the simulated wind speed. The simulated wind direction is also improved with the high-resolution data for both cases. Overall, our study indicates that wind forecasts can be improved through the application of the subgrid-scale orography parameterization and high-resolution topography/land-use data.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.4773-4780
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• 2014

Background: To investigate the effects of small interference RNA (siRNA) targeting BCR/ABL mRNA on proliferation and apoptosis in the K562 human chronic myeloid leukemia (CML) cell line and to provide a theoretical rationale and experimental evidence for its potential clinical application for anti-CML treatment. Materials and Methods: The gene sequence for BCR/ABL mRNA was found from the GeneBank. The target gene site on the BCR/ABL mRNA were selected according to Max-Planck-Institute (MPI) and rational siRNA design rules, the secondary structure of the candidate targeted mRNA was predicted, the relevant thermodynamic parameters were analyzed, and the targeted gene sequences were compared with BLAST to eliminate any sequences with significant homology. Inhibition of proliferation was evaluated by MTT assay and colony-formation inhibiting test. Apoptosis was determined by flow cytometry (FCM) and the morphology of apoptotic cells was identified by Giemsa-Wright staining. Western blotting was used to analyze the expression of BCR/ABL fusion protein in K562 cells after siRNA treatment. Results: The mRNA local secondary structure calculated by RNA structure software, and the optimal design of specific siRNA were contributed by bioinformatics rules. Five sequences of BCR/ABL siRNAs were designed and synthesized in vitro. Three sequences, siRNA1384, siRNA1276 and siRNA1786, which showed the most effective inhibition of K562 cell growth, were identified among the five candidate siRNAs, with a cell proliferative inhibitory rate nearly 50% after exposure to 12.5nmol/L~50nmol/L siRNA1384 for 24,48 and 72 hours. The 50% inhibitory concentrations ($IC_{50}$) of siRNA1384, siRNA1276 and siRNA1786 for 24hours were 46.6 nmol/L, 59.3 nmol/L and 62.6 nmol/L, respectively, and 65.668 nmol/L, 76.6 nmol/L, 74.4 nmol/L for 72 hours. The colony-formation inhibiting test also indicated that, compared with control, cell growth of siRNA treated group was inhibited. FCM results showed that the rate of cell apoptosis increased 24 hours after transfecting siRNA. The results of annexinV/PI staining indicated that the rate of apoptosis imcreased (1.53%, 15.3%, 64.5%, 57.5% and 21.5%) following treamtne with siRNAs (siRNA34, siRNA372, siRNA1384, siRNA1276 and siRNA1786). Morphological analysis showed td typical morphologic changes of apoptosis such as shrunken, fragmentation nucleus as well as "apoptotic bodies" after K562 cell exposure to siRNA. Western blot analysis showed that BCR/ABL protein was reduced sharply after a single dose of 50nmol/L siRNA transfection. Conclusions: Proliferation of K562 cells was remarkbly inhibited by siRNAs (siRNA1384, siRNA1276 and siRNA1786) in a concentration-dependent manner in vitro, with effective induction of apoptosis at a concentration of 50 nmol/L. One anti-leukemia mechanism in K562 cells appeared that BCR/ABL targeted protein was highly down-regulated. The siRNAs (siRNA1384, siRNA1276 and siRNA1786) may prove valuable in the treatment of CML.

• Progress in Medical Physics
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• v.19 no.2
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• pp.95-101
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• 2008

In this study, we observed the alteration of choline signal intensity in hippocampus region of the depressive rat model induced by forced swimming test (FST). The purpose of this study was to evaluate the antidepressant efficacy in the depressive animal model using MR spectroscopy. Fourteen experimentally naive male Sprague-Dawley rats weighting $160{\sim}180\;g$ were used as subjects. Drug injection group was exposed to the FST except for control group. The drugs were administered subcutaneously (SC) in a volume equivalent to 2ml/kg. And three injections were administered 23, 5, and 1h before beginning the given test. 1H MR spectra were obtained with use of a point resolved spectroscopy (PRESS) localization sequence performed according to the following parameters: repetition time, 2500 ms; echo time, 144 ms; 512 average; 2048 complex data points; voxel dimensions, $1.5{\times}2.5{\times}2.5\;mm^3$ ; acquisition time, 25min. There were no differences in NAA/Cr and Cho/Cr ratio between the right and the left hippocampus both normal control rats and antidepressant-injected rats. Also, no differences were observed in NAA/Cr and Cho/Cr ratio between the normal control rats and the antidepressant-injected rats both the right and the left hippocampus. In this study, we found the recovery of choline signals in the depressive animal model similar to normal control groups as injecting desipramine-HCl which was antidepressant causing anti-immobility effects. Thus, we demonstrated that MR spectroscopy was able to aid in evaluating the antidepressant effect of desipramine-HCl.