• Journal of Ecology and Environment
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• v.29 no.3
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• pp.305-321
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• 2006

Atmospheric Acid Deposition: Nitrogen Saturation of Forests: Volume weighted annual average wet deposition of nitroge at 33 sites in Korea during 1999-2004 ranged 7.28 to $21.05kgN{\cdot}ha^{-1}{\cdot}yr^{-1}$ with average $12.78kgN{\cdot}ha^{-1}{\cdot}yr^{-1}$, which values are similar level with nitrogen deposition of Europe and North America. The temperate forests that suffered long-term high atmospheric nitrogen deposition are gradually saturated with nitrogen. Such nitrogen saturated forest watersheds usually leach nitrate ion ($NO_3^-$) in stream water and soil solution. It may be likely that Korean forest ecosystems are saturated by much nitrogen deposition. In leaves with nitrogen saturation ratios of N/P, N/K and N/Mg are so enhanced that mineral nutrient system is disturbed, suffered easily frost damage and blight disease, reduced fine-root vitality and mycorrhizal activity. Consequently nitrogen saturated forests decrease primary productivity and finally become forest decline. Futhermore understory species are replaced the nitrophobous species by the nitrophilous one. In soil with nitrogen saturation uptake of methane ($CH_4$) is reduced and emission of nitrogen monoxide (NO) and nitrous oxide ($N_{2}O$) are increased, which gases are greenhouse gas accelerating global warming.

• Journal of Periodontal and Implant Science
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• v.26 no.4
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• pp.799-821
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• 1996

The ultimate goal of periodontal treatment has been to facilitate regeneration of diseased periodontal tissues, destroyed by inflammatory periodontal disease. For regeneration of the periodontium to occur, all of component tissues must be restored to their original position and architecture. Growth factors which were known to promote the cellular processes, ie, proliferation, migration and matrix synthesis, have been in the spotlight of current periodontics. Platelet-derived growth factor(PDGF) stimulates collagen and non collagen protein synthesis, migration and proliferation of periodontal ligament cells. Insulin-like growth factor(IGF) has potentials to induce collagen and bone matrix synthesis so that it regulates normal bone remodeling. Application of the combination have been known to facilitate formation of bone and cementum, and to synergistically interact to promote coronal migration and proliferation of periodontal ligament cells. These two growth factors have been reported to exhibit positive effect in the periodontally diseased teeth or class m furcation defects. The aim of the present study was to test the hypothesis that PDGF-BB alone or the combination of PDGF-BB and IGF-I can predictably enhance regeneration of the periodontium in the dehiscence defect. Following the resection of premolars, roots were embedded. After 12 weeks of healing period, standardized experimental $4{\times}4mm$ dehiscence defects were created on the mid-facial of the premolar roots in each of 4 young adult dogs. In control group, only methylcellulose gel was inserted in the defects. In experimental group I and II, gel with $2{\mu}g$ of PDGF-BB or $2{\mu}g$ of PDGF-BB and $1{\mu}g$ of IGF-I was inserted in the defects, respectively. At 8 weeks postsurgery, the dogs were sacrificed. The results were observed histologically and analyzed histomorphometrically.The results of this study were as follws. 1. The new cementum formation was $1.26{\pm}0.69mm$ in the control group, $1.80{\pm}0.84mm$ in the experimental group I, $1.93{\pm}0.51mm$ in the experimental group II. The experimental group III, the experimental group I, the control group were in the order of cementum formation without statistically significant differences between control and all experimental groups. 2. The new bone formation was $1.00{\pm}0.53mm$ in the control group, $1.53{\pm}0.63mm$ in the experimental group I, $l.33{\pm}0.45mm$ in the experimental group II. The experimental group I, the experimental group II, the control group were in the order of bone formation without statistically significant differences between control and all experimental groups. 3. The root resorption was $1.12{\pm}0.64mm$ in the control group, $1.34{\pm}0.73mm$ in the experimental group I, $0.79{\pm}0.59mm$ in the experimental group II without statistically significant differences between control and all experimental groups. These results suggested that the use of PDGF-BB alone or PDGF-BB and IGF-I in the dehiscence defects might facilitate periodontal regeneration in some degree, but has not shown statistically significant results.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.529-538
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• 1995

It has been believed that the increased release of free oxygen radicals ($O_2^-,H_2O_2$, and $OH^-$) might be a factor in the pathogenesis of periodontal diseases. Antioxidant enzymes such as glutathione peroxidase(GSH-PX) and catalase can protect the tissue damage from the $H_2O_2$. In order to investigate the GSH-PX and catalase activity in the blood plasma and red blood cells(RBCs) of the patients with periodontitis, 19 patients who had good general health, attachment loss more than 6 mm and bone loss were selected as periodontitis group, 7 patients who had severely inflamed gingiva were selected as gingivitis group, and 15 volunteers with good general and periodontal health were selected as normal group. 17 of 26 patients were performed scaling and root planing to reduce the gingival inflammation for gingivitis and periodontitis groups, and were selected as posttreatment group. After blood plasma and RBCs were collected and separated 1 ml of peripheral blood from each subject, GSH-PX activity in blood plasma and RBCs was measured by the same method that Stefan et al. did, and catalase activity in RBCs was measured by the same method that Beers et al. did. The difference of GSH-PX and catalase activity between normal, gingivitis, and periodontitis groups was statistically analyzed by ANOVA with SPSS/PC+ program, and the difference between pretreatment and posttreatment groups was analyzed by Student t-test. The results were as follows : 1. GSH-PX activity in blood plasma was significantly lower in the gingivitis group($0.8683{\pm}0.0658$), periodontitis group($0.7130{\pm}0.1333$) than in the normal group($1.0241{\pm}0.0801$)(p<0.05), and GSH-PX activity in RBCs was significantly lower in the gingivitis groupt. $0.8156{\pm}0.1167$), periodontitis group($0.7533{\pm}0.1185$) than in the normal group($l.1963{\pm}0.2044$)(P<0.05), but there was no statistical significance in the difference of GSH-PX activity in RBCs between the gingivitis group and periodontitis group(p>0.05). 2. Catalase activity in RBCs was siginficantly lower in the periodontitis group($117.34{\pm}35.01$) than in the normal group($l52.38{\pm}32.09$)(p<0.05). 3. GSH-PX activity in blood plasma was significantly increased in the posttreatment groupe $1.0376{\pm}0.2820$) compared to the pretreatment group(0.7608 0.1600) (p<0.05), and GSH-PX activity in RBC was significantly increased in the posttreatment group($1.0421{\pm}0.2330$) compared to the pretreatment group($0.7728{\pm}0.1210$)(p<0.05). 4. There was no statistical significance in the difference of catalase activity in RBCs between the pretreatment group($112.04{\pm}43.65$) and posttreatment group($l33.41{\pm}39.16$)(p>0.05).The results, within the limits of the present experiment, suggest that the lowered activity of GSH-PX and catalase in blood plasma and RBCs may be related with periodontopathogenesis.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.539-556
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• 1995

Periodontal therapeutic modalities should be re-establishing and regenerating the periodontal tissue previously lost to the disease. To achieve periodontal regeneration, periodontal ligament cells must selective migrate to the deneded root surface, attached and proliferated it. Local pH concentration is one of the most factors that periodontal regeneration. The aims of this study were to examine on biological effects of pH to the human periodontal ligament cells in vitro, especially on the cell morphology, attachment, activity, vitality and viability. Human periodontal ligament cells were cultured from extracted tooth for non-periodontal reason. Immediately after extraction, any soft tissue adhering to the cervical parts of the roots was carefully removed with a sterile curette. To produce different pH levels in the media, Eagle's MEM was adjusted from pH 6.6 to 8.2 in 0.2 intervals with 1 M NaOH and 1 N HCl. After cultivation, Then, Periodontal ligament cells were cultured at pH ranging from 6.6-8.2. attachment assay was done at 1, 2 day incubation and activity assay was done at 1, 2, 3 day incubation. The experiments were evaluated by scaning electron microscopic techniques (HITACHIX-650 Scaning Electron Microanalyzer, Tokyo, Japan), MTT assay, and the cultured periodontal ligament cells were fixed in neutral formalin for 24 hours and immunohistochemically processed by PCNA for proliferating ability. The surviving cells in the medium showed slightly increased volume and widening intercellular distances at low concentration of pH than control group (pH 7.4), and apparently shrinkage at high concentration of pH than control group (pH 7.4). The results of the statistical analysis from the experiment on attachment, vitality and viability were as follows. Attachment of periodontal ligament cells at 1st and 2nd day, similar attachment rate of low concentration pH compared with control value (pH 7.4). But above pH 8.0, attachment rate were statistically significant decrease from control value(P<0.05). Periodontal ligament cell's activities were maximum at pH 7.6 by MTT assay. Similar with control value at low concentration of pH. But, the activities were statistically significant decrease at high concentraration of pH(P<0.05). Cellular proliferating rate (PCNA index) were statistically significant decrease from control value at low and high concentration of pH(p<0.05). This results suggested that hjgh concentration pH, in other words, alkali pH was cytotoxic effects on human periodontal ligament cells in vitro.

• Journal of Periodontal and Implant Science
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• v.24 no.3
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• pp.633-648
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• 1994

Synthetic bone graft materials have been used for the regeneration of periodontal tissue lost due to periodontal disease, but the limitations of these materials had prompted the use of composite grafts. Among those, a composite graft of calcium carbonate(CC) and calcium sulfate(CS) is one of those materials that has not been studied extensively. CC, which is extracted from a natural coral, is known to possess osteoconductive property. SC can play an adjunctive role in the regeneration of bone tissue, and has shown good resorbability and biocompatibility. This study was conducted in order to investigate the effects of CC and CS composite graft to the regeneration of bone in the intrabony defects of dogs. 3-wall intrabony defects ub size of $4mm{\times}4mm{\times}4mm$ were created in the alveolar bone in the premolar areas. Then those defects that were treated with root planning only were designated as control, while the experimental group 1 and 2 each received the CC and CS composite grafts in the ratio of 8 : 2 and 5 : 5 the animals were sacrificed after 8weeks and the specimens were histologically analyzed. The results were as follows ; 1. No inflammation or foreign body reaction were observed in all subjects. CS has not been seen due to complete resorption, and resorption pattern of CC was observed. 2. Significant differences(p<0.05) in new cementum formation were observed between control($1.42{\pm}0.64mm$) and experimental groups(group 1 ; $2.53{\pm}0.94mm$, group 2 ; $2.23{\pm}0.96mm$) but the difference between the two experimental groups was not significant. 3. Significant differences(p<0.01) in new bone formation were observed between control($0.59{\pm}0.55mm$) and experimental groups(group 1 ; $2.27{\pm}0.61mm$, group 2 ; $2.05{\pm}0.56mm$) but the difference between the two experimental groups was not significant. 4. The extent of apical epithelial migration has shown no significant difference between control($1.18{\pm}1.24mm$) and experimental groups(group 1 ; $0.51{\pm}0.54mm$, group 2 ; $0.73{\pm}0.70mm$). 5. The extent of bone formation was generally limited to the extent of cementum formation for all groups, and significant correlation was found in the amount of bone formation and cementum formation in experimental group 1.(Co.=0.86, p<0.01) These results suggest that the composite graft of CC and CS is biocomplatible and effective in the new bone and new cementum formations. In the case of 3-wall intrabony defects of dogs, the composite ratio of 8 : 2 and 5 : 5 had shown no significant differences in the healing.

• Molecules and Cells
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• v.40 no.12
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• pp.966-975
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• 2017

Excessive salt disrupts intracellular ion homeostasis and inhibits plant growth, which poses a serious threat to global food security. Plants have adapted various strategies to survive in unfavorable saline soil conditions. Here, we show that humic acid (HA) is a good soil amendment that can be used to help overcome salinity stress because it markedly reduces the adverse effects of salinity on Arabidopsis thaliana seedlings. To identify the molecular mechanisms of HA-induced salt stress tolerance in Arabidopsis, we examined possible roles of a sodium influx transporter HIGH-AFFINITY $K^+$ TRANSPORTER 1 (HKT1). Salt-induced root growth inhibition in HKT1 overexpressor transgenic plants (HKT1-OX) was rescued by application of HA, but not in wild-type and other plants. Moreover, salt-induced degradation of HKT1 protein was blocked by HA treatment. In addition, the application of HA to HKT1-OX seedlings led to increased distribution of $Na^+$ in roots up to the elongation zone and caused the reabsorption of $Na^+$ by xylem and parenchyma cells. Both the influx of the secondary messenger calcium and its cytosolic release appear to function in the destabilization of HKT1 protein under salt stress. Taken together, these results suggest that HA could be applied to the field to enhance plant growth and salt stress tolerance via post-transcriptional control of the HKT1 transporter gene under saline conditions.

• Journal of Ginseng Research
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• v.32 no.4
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• pp.275-278
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• 2008

Ginseng stem fungus gnat, Phytosciara procera, is reported as a ginseng pest for the first time. It is new to science that a member of the family Sciaridae is a ginseng pest. In our observation, larvae of the gnat can penetrate the stem of ginseng, and then they make a shaft in shoot and root. Number of adults captured by yellow sticky traps were peaked in twice, from late July to early August and from late August to early September. In a ginseng field, 29.7% of ginseng damaged by Phytosciara procera is also infected by bacterial disease caused by Erwinia carotobora. However, there is a possibility on environmental-friendly control, as a result of decreasing effect of damage over 85% when remaining a part of berry on peduncle than tatally remove.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.201-201
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• 2017

Delayed stem senescence of soybean is a phenomenon of retarded leaf and stem yellowing, where plants maintain a high stem water content and remain chlorophyll in leaf and stem at maturity stage. This phenomenon was one of the most important physiological disease in Japanese soybean cultivation. The occurrence of delayed stem senescence was affected by sowing time. And the most of Japanese field, soybean seeds were sowed in June. June is the rainy season in Japan, and the soil water content of field become higher in this season. In this study, the effects of late sowing (July sowing) on the yield and the occurrence of delayed stem senescence in soybean cultivars Enrei, Tachinagaha and Ayakogane were examined from 2013 to 2015, in the experimental farm at Nihon University (Fujisawa-city, Kanagawa, Japan). The seeds of all cultivars were sowed in June (June-normal density plot) or July (July-normal density plot, July-high density plot and July-super high density plot) in field experiment. The pot experiments were carried out in 2014. In all cultivars, the yield of July-high density plot and July-super high density were higher than that of June normal density plot. And the yield of June-normal density plot was the same as that of July-normal density plot. In all cultivars, the occurrence of delayed stem senescence was increased by seeding in June sowing. And in July sowing plots, no significance difference in the occurrence of delayed stem senescence was observed among density plots. One of reason about the increasing the occurrence of delayed stem senescence in June-normal plot was the increasing of the damaged seeds by bean bugs. Add one of reason about the decreasing of the occurrence of delayed stem senescence of July plots was the decreasing of the amount of cytokinin supplied from root to top and water stress after the flowering time was improved compared with the June plot. In conclusion, the yield of Enrei, Tachinagaha and Ayakogane were not changed by changing the sowing time from June to July. In all cultivars, the occurrence of delayed stem senescence were decreasing by seeding in July.

• Research in Plant Disease
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• v.12 no.3
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• pp.197-204
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• 2006

Crown gall on lower stem and root of chrysanthemum(Dendranthema grandiflorum Kitamura) was observed at Hwasung and Gumi in 2001 and 2004, respectively. Tumors were semi-round with rough surface texture of dark brown color. Nine isolates inducing gall formation on lower stem of chrysanthemum among twenty isolates from the tumor tissues were characterized. Their colonies were convex, glistening, circular with an entire edge and whitish or tannish cream in color on potato dextrose agar supplemented with 0.5% $CaCO_3$. The virulent isolates were rod-shaped with peritrichous flagellae, gram negative, aerobic and growing on D1M agar. Among nine virulent isolates, one isolate was identified as Agrobacterium rubi and eight isolates were A. tumefaciens based on biochemical and physiological characteristics, fatty acid profiles and substrate utilization patterns. A. tumefaciens had strong pathogenicity and broad host range compared with A. rubi. This is the first report on crown gall of chrysanthemum in Korea. To our knowledge, crown gall of chrysanthemum caused by A. rubi is first report in this study worldwide.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.2
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• pp.144-152
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• 2005

To evaluate the effect of lead biomarkers including bone lead on neurobehavioral test in lead workers, 652 lead workers without any occupational exposure to organic solvent, mercury and arsenic were agreed to participate this study. For the control subjects 102 non-occupationally lead exposed blue collar workers in general manufacturing industries were also joined this study. All study subjects joined this study with written informed consent. The study variables of lead exposure were blood and patella lead. For the general characteristics of study subjects, standardized questionnaire regarding age, sex, past disease history, job duration, body mass index (BMI), drinking and smoking habit were provided. For the past history of neurotoxicity related diseases, all study subjects were interviewed by qualified occupational health physician. The results obtained were as follows: 1. Compared with controls without occupational lead exposure, lead exposed subjects had worse performance on all tests(p<0.05). 2. After adjustment for covariates (age, sex, job duration, education level, BMI, smoking and drinking status), the signs of the regression coefficients for blood lead were negative for 13 of the 14 tests. Blood lead was a significant predictor of poorer scores on 8 tests (simple reaction time(ms & root MSD), Trail-Making Test B, Digit Symbol Substitution, Purdue Pegboard assembly, Digit Span Test, Benton Visual Retention, and Purdue pegboard both hand). 3. After adjustment for covariates (age, sex, job duration, education level, BMI, smoking and drinking status), the signs of the regression coefficients for patella lead were negative for 12 of the 14 tests. Patella lead was a significant predictor of poorer scores on 8 tests (simple reaction time(ms). Purdue Pegboard assembly, Digit Span Test, Benton Visual Retention. Pursuit Aiming rest (no. of correct & no. of incorrect), Purdue pegboard non-dominant hand and both hand). With above results, blood lead and patella lead were associated with poorer performance of neurobehavioral tests. In addition, patella lead was confirmed to be better predictor of manual dexterity test in neurobehavioral test battery in lead workers