• The Korean Journal of Mycology
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• v.51 no.4
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• pp.447-460
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• 2023

Fire blight, a plant disease caused by Erwinia amylovora, continues to cause considerable damage to fruit-bearing trees belonging to the Rosaceae family, such as apples and pears. In Korea, to hinder its rapid spread diseased apple and pear trees have been buried since its first occurrence. To determine the safety of this control method, the buried plant materials and adjacent soil have been investigated. In the process of investigating the microbiota of the buried soil, Bisifusarium allantoides, Botryotrichum domesticum, Microascus verrucosus, Paraphoma pye, Phaeosphaeria culmorum, Ramophialophora globispora, Sordaria tomentoalba, and Striaticonidium brachysporum were identified as unrecorded species in Korea. To report the above eight species as Korean unrecorded species, we report their morphological and molecular features in this study.

• Ocean and Polar Research
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• v.34 no.2
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• pp.137-149
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• 2012

Hemocyte parameters of the wild Pacific oyster Crassostrea gigas inhabiting intertidal zones in small bays (Gwangyang and Jinhae Bay) on the southern coast of Korea were evaluated using flow cytometry and neutral red retention (NRR) assay. Morphological features, cell count, mortality, DNA damage, phagocytosis, and lysosomal membrane stability of hemocytes were analyzed. Three types of hemocytes were identified in the oyster hemolymph: granulocytes, hyalinocytes, and blast-like cells. Immune related functions of hemocyte including phagocytosis and lysosomal membrane stability were significantly different among the study areas (P<0.05), while cell count, mortality, and DNA damage of hemocytes were not significantly different. In Gwangyang Bay, phagocytosis of granulocytes and lysosomal membrane stability of oyster hemocytes inhabiting inside bay were significantly lower than those of oyster hemocytes in outside bay (P<0.05), indicating that oysters in inside bay of Gwangyang were relatively suppressed the immunological function in hemocytes. Contrary to Gwangyang Bay, immune parameters of oyster hemocytes in Jinhae Bay not showed the difference between sampling sites. In conclusion, flow cytometry and NRR assay using oyster hemocyte has a powerful tool to investigate the cell level in a short time due to no-preprocessing of material.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.7
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• pp.828-834
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• 2006

We investigated whether two-kinds of mixture (NHDT-1 and NHDT-2) mainly composed of Hovenia dulcis Thunb had beneficial actions for alcohol and acetaldehyde degradation in acute alcohol treatment and liver protection from fatty liver induced by chronic alcohol administration. In acute alcohol degradation experiment, serum alcohol and acetaldehyde concentrations exhibited lower 1, 3 and 5 hours after taking 3 g ethanol per kg body weight in NHDT-1 treated rats, but not NHDT-2 including ginseng. On the contrast to the acute effect on alcohol degradation, the long-term alcohol administration revealed that NHDT-2, not NHDT-1, protected the increase in serum concentration of aspartate aminotransferase, alanine aminotrasferase and ${\gamma}-triglyceride$ metabolism similar to the rats not consuming alcohol, leading to decreased triglyceride accumulation in blood and liver. In liver morphological study, NHDT-1 preserved the regular hepatocyte morphology, decreased fat accumulation and reduced sinusoidal leukocyte infiltration in hepatocytes. In conclusion, NHDT-1 plays an important role in alcohol and acetaldehyde degradation without protecting liver damage while NHDT-2 works as hepatocyte protector from alcohol mediated damage.

• Restorative Dentistry and Endodontics
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• v.16 no.2
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• pp.155-164
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• 1991

The purpose of this study was to evaluate the effects of bleaching agent through the dentinal tubules of cervical area in the intracoronal bleaching of pulpless teeth on cutured fibroblast cells. Extracted human incisors were enlarged to # 40 K-file and obturated with gutta-perella and AH 26 sealer. The gutta-percha was removed to 2mm below the cementoenamel junction of the root The teeth were divided into 3 experimental and control groups. Experimental groups; Experimental group 1: Temporary inlay wax filld with 30% $H_2O_2$ in pulp cavity. Experimental group 2: Temporary inlay wax filld with 30% $H_2O_2$ in pulp cavity after placement of ZOE cement to cementoenamel junction. Experimental group 3: Temporary inlay wax filld with 30% $H_2O_2$ in pulp cavity after application of Copalite to cementoenamel junction. Control group: Temporary inlay wax filled without 30% $H_2O_2$ in pulp cavity under the same condition at each experimental group. Each tooth was immersed in well of multidish cultured fibroblast cell for 48 hours. The cellular multiplication and cell viability were calculated at the interval of 1, 3, 5. 7 hours and the morphological changes in well were observed and their photographs were taken with inverted microscope. The obtained results were as follows : CD The cellurar multiplicaton and cell viability decreased in all experimental groups at 1 hour after experiment and the morphology of fibroblast cell was changed from star shape to round (2) The cell viability was lowered to 34 % in experemental group 1, 44 % in experimental group 2, and 38 % in experemental group 3 at 3 hours after experiment (3) The cell multiplication was decreased to 54% in experemental group 1. 47% in experimental group 2, and 40% in experemental group 3 at 7 hours after experiment. (4) The decrease of cell number and morphological changes of fibroblast cell were remarkable in experimental group 1, group 3 and 2 in order. These results suggest that the fibroblast cells receive severe damage by 30% $H_2O_2$ solution leaked through the dentinal tubules and the dentinal tubules are able to be obturated better by ZOE cement than by Copalite.

• The Journal of Korean Medicine
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• v.26 no.1 s.61
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• pp.174-186
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• 2005

Objectives : The water extract of Samul-tang (SMT) has traditionally been used for treatment of ischemic heart and brain damage in oriental medicine. However, little is known about the mechanism by which the water extract of SMT rescues cells from these damages. Methods: This study was designed to investigate the protective mechanisms of SMT on oxidative stress-induced toxicity in H9c2 cardiomyoblast cells. Treatment with $H_2O_2$ markedly induced death of H9c2 cardiomyoblast cells in a dose-dependent manner. Results: The characteristics of H20z-induced death of H9c2 showed apparent apoptotic features such as DNA fragmentation and morphological change. However, SMT significantly reduced both H202-induced cell death and morphological change. The decrease of Bc-2 expression by High were inhibited by SMT. In addition, the increase of Bax expression was also inhibited by SMT. The cotreatment of SMT and $H_2O_2$ in H9c2 cells also induced the phosphorylation of ERK in a time-dependent manner. Moreover, PD98059, a specific inhibitor of ERK1/2 attenuated the protective effects of SMT on $H_2O_2-induced$ toxicity in H9c2 cardiomyoblast cells. These results suggest that both ERK1/2 signaling pathways play important roles in the protective effects of SMT on $H_2O_2-induced$ apoptotic death of H9c2 cells. Also, the expression profile of proteins in $H_2O_2$ cardiomyoblast cells were screened by using two-dimensional (2-D) gel electrophoresis. Among 300 spots resolved in 2-D gels, the comparison of control versus apoptosis cells revealed that signal intensity of 17 spots increased and 11 spots decreased. Conclusions: Taken together, this study suggests that the protectiw effects of the water extract of SMT against oxidative damages may be mediated by the modulation of Bc1-2 and Bax expression via the regulation of the ERK signaling pathway.

• Journal of Applied Biological Chemistry
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• v.61 no.4
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• pp.397-403
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• 2018

The leaves of Spiraea prunifolia were extracted with 80% aqueous MeOH and the concentrates were partitioned into EtOAc, n-BuOH, and $H_2O$ fractions. The repeated $SiO_2$ or ODS column, and medium pressure liquid chromatographies for the n-BuOH fraction led to isolation of two phenolic glucosides. The chemical structures of these compounds were determined as isosalicin (1) and crenatin (2) based on spectroscopic analyses including Nuclear magnetic resonance and MS. Extracts were analyzed using UPLC-MS/MS providing a short analysis time within 5 min using MRM technique. The concentration of crenatin was higher as 9.53 mg/g and isosalicin was lower as 0.65 mg/g. Neuroprotective effects of these compounds against hydrogen peroxide ($H_2O_2$)-induced neurotoxicity were evaluated. The results showed that exposure to $H_2O_2$ induced morphological changes, cell death and neurotoxicity in SK-N-MC cells. However, pretreatment with crenatin resulted in inhibition of morphological change, reduction of loss of cell viability and attenuation of neuronal damage. These results suggested that neuroprotective effect of crenatin isolated from S. prunifolia can be a good candidate for the development of health beneficial foods which can ameliorate the degenerative neuronal disease caused by oxidative stress.

• Journal of Wetlands Research
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• v.23 no.2
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• pp.154-162
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• 2021

The naturally opened Han river estuary is a place where the flows of the Han river, Imjin river, Yaesung river meet with West Sea of Korea, so the hydrodynamic mechanism(Impact-Response) structure of Han river estuary is complex. Continuous observation and measurement due to the morphological characteristics at the estuary are required to maintain the estuary environment and river management facilities. However, the Sannam wetland(the study area) is in the military operation area. Therefore, Sannam wetland has the limited access under the control from military office. In 2020, there had a natural disaster due to flooding in August and COVID-19, and it made a survey hard. The noncontact survey technique, the analysis of LANDSAT images at Sannam wetland, was applied to analyze riverbed fluctuation and morphological transformation around Sannam wetland. LANDSAT images obtained from EarthExplorer, USGS and analyzed by QGIS. The analysis was performed based on the area and the distance near Sannam wetland. As a result, an erosion was happened on the downstream of the study area, and the upstream of the study area did not have any serious sediment transport. Considering the resolution of LANDSAT images, this noncontect survey technique is applicable to manage the study area. From the analysis of LANDSAT images, it is assumed that the tidal effect is greater than the inflow from the upstream. The pattern change of tidal response causes the damage of the river facilities near the Hangang river estuary.

• The Korean Journal of Pharmacology
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• v.31 no.1 s.57
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• pp.95-102
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• 1995

The pathogenesis of diabetic nephropathy is still not completely understood while renal disease is one of the most common disabling complications of diabetes. We, in the present study, investigated the possible involvement of oxidative stress in the development of diabetic nephropathy. To hasten the development of diabetic nephropathy, streptozotocin was injected to unilaterally nephrectomized rats (NEPH-STZ). Eight weeks later, NEPH-STZ rats developed severe hyperglycemia, proteinuria, and hypertension. The kidneys of these rats showed compensatory hypertrophy and mesangial expansion. In contrast, the rats with streptozotocin injection alone (STZ) did not increase urinary protein excretion. Nephrectomized non-diabetic rats (NEPH) developed increased urine protein excretion, but without prominent renal morphological changes. However, oxidation of renal cortical tissue protein significantly increased in all 3 groups of NEPH, STZ and NEPH-STZ in comparison to control rats (CONT). The result indicates the non-specificity of the oxidative tissue damage and suggests that the oxidative damage is hardly a sole mechanism leading to the development of the diabetic nephropathy. However, it would still be a contributing factor considering that the oxidative stress is a common final pathway mediating tissue damages in chronic diabetic complications and other serious illness.

• Korean journal of applied entomology
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• v.22 no.2 s.55
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• pp.52-66
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• 1983

The brown planthopper, N. lugens (Stal), has become a serious pest of rice in tropical Asia during the last decade. At high pest density, its feeding damage causes 'hopperburn' or complete wilting and drying of the rice plant. It also transmits grassy and ragged stunt virus diseases. The estimated losses caused by the pest in tropical Asia exceed $US\$300$ millions. While cultivation of resistant rice varieties has proved to be highly effective against the pest, their long-term stability is threatened because of the evolution of prolific biotypes which can destroy these varieties. At present, identification of biotypes is based principally on the differential reactions of host rice varieties to the pest and on host-mediated behavioral and physiological responses of the pest. Recent findings of morphological differences in adult rostrum, legs, and antennae, body parts that possess receptors for host plant location and discrimination, and cytological differences in N. lugens populations maintained as stock cultures strongly complement other biotype studies. So far, three N. lugens biotypes have been identified in the Philippines. Biotype I can survive on and damage varieties that do not carry and genes for resistance, while Biotype 2 survives on resistant varieties carrying Bph 1 gene and Biotype 3 on varieties carrying gene bph 2. However, none of these biotypes can survive on varieties with genes Bph 3 or bph 4. Several varieties which are resistant in the Philippines are susceptible in India and Sri Lanka as the South Asian biotypes of N. lugens are more virulent than Southeast Asian biotypes. To monitor the pest biotypes in different geographical regions and to identify new sources of resistance, an International Brown Planthopper Nursery has been established in many cooperating countries. The evolution of biotypes is an exceedingly complex process which is governed by the interactions of genetic and biological factors of the pest populations and the genetic makeup of the cultivated varieties. While the strategy for sequential release of varieties with major resistance genes has been fairly successful so far, the monegenic resistance of these varieties makes them vulnerable to the development of the pest biotypes. Therefore, present breeding endeavors envisage utilizing both major and minor resistance genes for effective control of the pest.

• Journal of radiological science and technology
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• v.26 no.3
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• pp.41-49
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• 2003

This study was undertaken to observe the histopathologic changes in submandibular glands of the white rats when exposed to megavoltage fractionated dose of CLINAC 2100 C-D 6 MV X-RAY irradiation and 42 female white rats, weighing approximately 100gm, were divided into control and 2 experimental groups. At sacrifice, submandibular glands were excised and examined microscopically and electromicroscopically. The results were as follows : 1. The acinar cells of submandibular gland showed damage varied with dose, 12 Gy resulted in very mild injury while 24 Gy caused extensive injury. 2. The acinar cells of sumandibular gland showed similar ultrastructual alterations, appeared as pleomorphic nucleus, decreased numbers and pleomorpgism of secretory granules, distention of rough endoplasmic reticulum, expansion and pallor appearance of mitochondria, and hypertrophy of Golgi complex. 3. A serous cells were the most sensitive components, displaying morphological alterations of radiation damage as early as 3 hours, followed by submandibular seromucinous cells and secretory tubular cells. 4. The mucous cells, as well as the whole ductal lining cells, displayed no significant alterations. 5. No evidence of microvascular injury through whole experimental groups indicated that microvascular impairment dose not contribute to early. salivary gland injury.