• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.213-219
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• 2007

It has been well established that aluminum (Al) inhibits root tip growth rapidly in acid soil. We report the correlation between Al induced growth inhibition and impaired $H^+-flux$ in mung bean (Vigna radiate L. cv. Kumsung). The root growth inhibition was dependent on Al concentration (0, 10, 25, 50, $100{\mu}M$) and exposure time (12 and 24 h). Using Hematoxylin staining, it was observed that the root damage was occurred preferentially in regions with high Al accumulation. Using the pH indicator, it was shown that the surface pH of root tip was strongly alkalized in the control whereas changed only slightly in the $50{\mu}M$ Al-treated root. The $H^+-ATPase$ activity of plasma membrane vesicles was inhibited by 56% in the Al-treated roots compared to control root. Decrease in the amount of the plasma membrane $H^+-ATPase$ (100 kDa) translation in the plant roots under Al stress was demonstrated by Western blot analysis. These results indicate that the dynamics of $H^+-flux$ across the root tip play an important role in root growth under Al stress.

• Journal of Applied Biological Chemistry
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• v.59 no.1
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• pp.31-36
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• 2016

Chlorine dioxide has been used for a disinfectant by exhibiting antimicrobial activity and is also potent to kill insect pests infesting stored grains. This study aimed to extend the usefulness of chlorine dioxide with respect to anticancer and antiviral activities. Cytotoxicity of chlorine dioxide was assessed against five different human cancer cell lines. Chlorine dioxide exhibited significant cytotoxicity against two breast cancer cell lines (MCF-7, MDA-MB-231) and three colorectal cancer cell lines (LoVo, HCT-116, SW-480). This cytotoxicity appeared to be associated with the capacity of chlorine dioxide to induce the production of reactive oxygen species (ROS). Compared to control insect cell lines, the cancer cell lines possessed much higher levels of ROS. On the other hand, a treatment of an antioxidant, vitamin E, significantly reduced the cytotoxicity, suggesting that the cytotoxicity was induced by high levels of ROS production. Chlorine dioxide exhibited antiviral activity against different viruses. A baculovirus, Autographa californica nuclear polyhedrosis virus (AcNPV), is a dsDNA insect virus and lost its viral activity to form polyhedral viral particles in response to chlorine dioxide. The antiviral activity against AcNPV was dependent on the incubation time with chlorine dioxide. Tobacco mosaic virus is a ssRNA plant virus and was reduced in its population after exposure to chlorine dioxide along with significant decrease of viral symptoms. These results indicate that chlorine dioxide possesses anticancer and antiviral activities probably due to its inducing activity of ROS production.

• The Korean Journal of Pharmacology
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• v.30 no.1
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• pp.87-100
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• 1994

It has been known for some time that dopamine-containing cells are existed in sympathetic ganglia, i.e., small, intensely fluorescent cells. However, its role and mechanism of action as a peripheral neurotransmitter are poorly understood so far. In the present study, an attempt was made to examine the effect of apomorphine, which is known to be a selective agonist of dopaminergic $D_2$. receptor on secretion of catecholamines (CA) from the isolated perfused rat adrenal gland. The perfusion of a low concentration of 10uM apomorphine into an adrenal vein for 20 min produced significant reduction in CA secretion induced by 5.32 mM ACh, 56 mM KCl, 100 uM DMPP and 100 uM McN-A-343. Increasing apomorphine concentration to 30 uM led to more markedly decreased CA secretion as compared to the case of 10 uM apomorphine and also did inhibit clearly CA release by $10^{-5}M$ Bay-K-8644. Furthermore, in adrenal glands preloaded with a higher dose of 100 uM apomorphine, CA releases evoked by ACh, excess $K^+$, DMPP and McN-A-343 were almost abolished by the drug. The perfusion of $3.3{\pm}10^{-5}M$ metoclopramide, which is well-known as a selective dopaminergic $D_2$ antagonist, produced significantly inhibitory effect of CA release by ACh, DMPP and McN-A-343 but did not affect that by excess $K^+$. However, preloading of 30uM apomorphine in the presence of metoclopramide did not modify the CA secretory effect of excess $K+$ and DMPP. These experimental results demonstrate that apomorphine causes dose-dependent inhibition of CA secretion by cholinergic receptor stimulation and also by membrane depolarization from the isolated perfused rat adrenal gland, suggesting that these effects appear to be exerted by inhibiting influx of extracellular calcium into the rat adrenal medullary chromaffin cells through activation of inhibitory dopaminergic receptors.

• The Korean Journal of Pharmacology
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• v.18 no.1
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• pp.43-54
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• 1982

Bile formation is a complex process comprised of three separate physiologic mechanism operating at two anatomical sites. At present time, it was known that at least two processes are responsible for total canalicular secretion at the bile canaliculus. One of the processes is bile salt-dependent secretion (BSDS) hypothesis that the active transport of bile salts from plasma to bile provided a primary stimulus for bile formation: the osmotic effect of actively transported bile acid was responsible for the movement of water and ions into bile. The other process is bile salt-independent secretion (ESIS), which is unrelated to bile salt secretion at the canaliculus and which may involve the active transport of sodium. The third process for bile formation involves the biliary ductal epithelium. Secretin-stimulated bile characteristically contained bicarbonate in high concentration. Therefor, it was suggested that secretin stimulated water and bicarbonate secretion from the biliary ductules. One the other hand, it was found that a large amounts of cAMP was present in canine bile but no apparent relationship between bile salt secretion and cAMP content in dog bile. However, bile flow studies in human have demonstrated that secretin and glucagon increase bile cAMP secretion as does secretin in baboons. Secretin increases baboon bile duct mucosal cAMP levels in addition to bile CAMP levels suggesting that in that species secretin-stimulated bile flow may be cAMP mediated. It has been postulated that glucagon and theophylline which increase the bile salt-independent secretion in dogs might act through an increased in liver cAMP content. In a few studies, the possible role of cAMP on bile formation has teen tested by administration of an exogenous derivative of cAMP, dibutyryl cAMP. In the rat, DB cAMP did not modify bile flow, but injection of DB cAMP in the dog promoted an increase in the bile salt-independent secretion. Because of these contradictory results, this study was carried out to examine the relationship between cyclic nucleotides and bile flow due to various bile salts as well as secretin or theophylline. Experiments were performed in rabbits with anesthesia produced by the injection of seconal(30 mg/kg). Rabbits had the cystic duct ligated and the proximal end of the divided common duct cannulated with an appropriately sized polyethylene catheter. A similar catheter was placed into the inferior vena cava for administration of drugs. Bile was collected for determination of cyclic nucleotides and total cholate in 15 min. intervals for a few hours. The results are summerized as followings. 1) Administrations of taurocholic acid or chenodeoxycholic acid increased significantly the concentrations of cAMP and cGMP in bile of rabbits. 2) Concentration of cAMP in bile during the continuous infusion of ursodeoxycholic acid, was remarkedly increased in accordance with the increase of bile flow, while on the contrary concentration of cGMP in bile was decreased significantly. 3) Dehydrocholic acid and deoxycholic acid significantly increased bile flow, total cholate output and cyclic nucleotides in bile. 4) Only cAMP concentration in bile was significantly increased from control value by secretin, while theophylline increased cAMP as well as cGMP in rabbit bile. 5) In addition, the administration of secretin to taurocholic acid-stimulated bile flow increased cAMP while theophylline produced the increases of cAMP and cGMP in bile. 6) The administration of insulin to taurocholic acid-stimulated bile flow decreased cAMP concentration, while on the contrary cGMP was remarkedly increased in rabbit bile.

• Clinical and Experimental Pediatrics
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• v.45 no.6
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• pp.732-742
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• 2002

Purpose : In order to evaluate the hypoxia-ischemia(H-I) induced neurotoxicity and the protective effect of xanthine oxidase(XO) inhibitor(allopurinol), cell number, cell viability, lactate dehydrogenase(LDH), protein synthesis(PS) and protein kinase C(PKC) activity were measured in cerebral neurons and astrocytes. Methods : Cytotoxic effect was measured by in vitro assay at 12-72 hours after H-I on cerebral neurons and astrocytes derived from 7-day old neonatal rats which were subjected to unilateral common carotid artery occlusion and exposed to hypoxic condition for 3 hours. The protective effect of XO inhibitor was examined by the cell number, cell viability, LDH and PS on 14 days after H-I with allopurinol intraperitoneal injection 15 minutes prior to H-I. In addition, the effect of allopurinol on PKC activity in hypoxic conditions was examined in neurons. Results : 72 hours from H-I, the cell numbers and viability were decreased significantly in time-dependent manner on neurons and those of astrocytes also decreased slightly, compared with control. In neonatal rats treated with H-I, the cell number, cell viability, and PS in neurons were decreased, but LDH was increased significantly compared with control. In neonatal rats pretreated with allopurinol, the cell number and viability, and PS in neurons were increased and LDH was decreased significantly compared with H-I. PKC was increased remarkably after hypoxic condition. But PKC was decreased significantly against hypoxic condition after allopurinol pretreatment. Conclusion : From these results, it is suggested that H-I is more toxic in neurons than astrocytes and allopurinol is very protective with increasing of PS, and decreasing of LDH and PKC in neurons from hypoxic-ischemic condition.

• Clinical and Experimental Pediatrics
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• v.52 no.9
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• pp.1015-1020
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• 2009

Purpose:The aim of this study is to explore the effect of the Toll-like receptor 9 (TLR9) expressed in plasmacytoid dendritic cells (pDCs) that respond to antigen to Th2 immune deviation in allergic patients. Methods:Subjects consisted of 19 allergic patients and 17 healthy volunteers. Skin prick tests and nasal provocation tests were performed for the two groups. Peripheral blood mononuclear cells (PBMCs) were collected from subjects and analyzed for the Lineage Cocktail (CD3, CD14, CD16, CD19, CD20, CD56) (-), HLA-DR (+), and CD123 (+) using flow cytometry. In addition, we analyzed TLR9 mRNA by reverse transcriptase-polymerase chain reaction. The level of $interferon-{\alpha}$ ($IFN-{\alpha}$) of the PBMCs following stimulation with the TLR9 ligand CpG-ODN 2216 was also evaluated. Results:Analyses of CD123 (+) revealed a nearly similar distribution for the classical pDC markers in the allergic group ($0.1%{\pm}0.04%$) and in the controls ($0.25%{\pm}0.23%$). The mRNA levels of TLR9 on PBMCs were not different between the allergic group and the controls ($1.29{\pm}0.41$ vs. $1.25{\pm}0.23$, respectively). Additionally, the level of $IFN-{\alpha}$ in PBMCs exposed to stimuli of the TLR9 ligand CpG-ODN 2216 was not significantly different between the two groups ($911{\pm}829$ vs. $1,095{\pm}888pg/mL$, respectively). Conclusion:We found no evidence that TLR9-dependent immune responses in human pDCs are associated with allergic status.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.181-186
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• 1988

This experiment was conducted to examine the $PGF{2{\alpha}}$-induced changes in concentrations of ovarian and pituitary hormones of Korean native goats. Each goats received two injections of $PGF{2{\alpha}}$ (5mg each ; 3 hours apart) on day 10 of the estrous cycle. Jugular venous blood samples were collected at 0, 3, 6, 12, 24, 48 and 72 hours postinjection for quantification of LH, FSH, prolactin, progesterone and estradiol-$17{\beta}$. The results were summarized as follows ; The blood serum concentration of progesterone was decreased from pretreatment level of $4.15{\pm}1.8ng/ml$ to $2.52{\pm}1.2ng/ml$ (about 60%) within 3 hours and to $0.81{\pm}0.3ng/ml$ at 12 hours of the $PGF{2{\alpha}}$ injection. After 12 hours, the concentrations of progesterone were less than 1.02ng/ml by 72 hours postinjection. The concentrations of estradiol-$17{\beta}$ following treatment increased (p < 0.05) over the 72 hours. Initial concentration of LH was $3.0{\pm}0.3{\mu}IU/ml$. After treatment with $PGF{2{\alpha}}$, concentrations of LH increased within 12 hours but declined 12 and 72 hours from $4.1{\mu}IU/ml$ to $2.5{\mu}IU/ml$. Prior to administration of $PGF{2{\alpha}}$, mean concentration of FSH was $3.5{\pm}0.5{\mu}IU/ml$. Concentrations of FSH declined over time in goats treated with $PGF{2{\alpha}}$ on day 10 postestrus. The mean prolactin concentrations in the blood serum after $PGF{2{\alpha}}$ treatment were not significantly different from those of the pretreatment. It is concluded that the initial increase in LH is dependent on a decrease in serum progesterone and differences in patterns of secretion of gonadotropins might be caused by differences in progesterone or progesterone-estradiol ratio when luteal regression is induced on day 10 of the estrous cycle.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.5
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• pp.761-767
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• 2007

This study was conducted to determine the effects of exogenous zinc-metallothionein (Zn-MT) on anti-oxidative function and pork quality. After feeding a corn-soybean meal-based diet for two weeks, 48 pigs ($Duroc{\times}Landrace{\times}Chinese\;Black Pig$) were assigned randomly to four groups. Pigs in Group 1 were maintained under non-stress conditions, whereas pigs in Groups 2, 3 and 4 were aggressively handled for 25 min to produce stress. Pigs in Groups 1, 2, 3, and 4 received intramuscular administration of saline (control group; CON), 0 (negative control group; NCON), 0.8 (low dose group; LOW), and 1.6 (high dose group; HIGH) mg rabbit liver Zn-MT per kg body weight, respectively. Pigs were slaughtered at 3 and 6 h post-injection. Zn-MT treatment increased (p<0.05) the activities of superoxide dismutase (SOD) and glutathione-peroxidase (GSH-PX) while decreasing the concentration of malondialdehyde (MDA) in liver. These responses were greater (p<0.05) at 6 h than at 3 h post Zn-MT injection. Zn-MT treatment increased (p<0.05) hepatic SOD mRNA levels in a time and dose-dependent manner and decreased (p<0.05) serum glutamate-pyruvate transaminase and lactate dehydrogenase activities (indicators of tissue integrity). Zn-MT administration decreased (p<0.05) lactate concentration and increased (p<0.05) pH and water-holding capacity in the longissimus thorasis meat. Collectively, our results indicate that intramuscular administration of Zn-MT to pre-slaughter stressed pigs improved tissue anti-oxidative ability and meat quality.

• Journal of Nutrition and Health
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• v.53 no.4
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• pp.390-405
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• 2020

Purpose: The effect of prebiotics intake after administration of a synbiotics mixture (a probiotic, Bifidobacterium longum, and a prebiotic, xylooligosaccharide containing sugar [XOS]) on human intestinal microflora and defecation characteristics was investigated in a randomized controlled trial. Methods: Twenty-five healthy young volunteers (11 males and 14 females) were randomly assigned to 2 groups (BL2XO2 and BL2XO6). The synbiotics mixture was orally administered to both groups for 2 weeks, and the prebiotics were subsequently administered to the BL2XO6 group for 4 additional weeks. The daily dose of the synbiotics mixture comprised 10¹⁰ colony-forming unit of Bifidobacterium longum and 10 g of XOS, and during the prebiotics period, the daily dose of prebiotics comprised only 10 g of XOS. The fecal pH, microflora, and defecation characteristics were analyzed at baseline and at weeks 1, 2, 4, and 6. Results: The counts of B. longum and Bifidobacterium spp. in the BL2XO6 group exhibited a steady, increasing trend during the synbiotics and prebiotics periods, whereas those of the BL2XO2 group exhibited considerable variation in each week of the study period. Although there was no significant difference, the counts of fecal Bifidobacterium in the BL2XO6 group tended to be higher than those of the BL2XO2 group at week 6. The growth of Lactobacillus spp. exhibited a time-dependent variation, peaking at week 6 in both groups. Low counts of Clostridium spp. were observed after treatment with the synbiotics and prebiotics in the BL2XO6 group (p < 0.05) throughout the study, whereas the inhibitory effect on Clostridium spp. was maintained only during the synbiotics period in the BL2XO2 group. The defecation characteristics did not differ between the two groups. Conclusion: Administration of XOS after a synbiotics mixture containing B. longum and XOS can exert a prebiotic effect in healthy young volunteers by stimulating Bifidobacteriun spp. growth and inhibiting growth of Clostridium spp.

• Journal of Intelligence and Information Systems
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• v.21 no.2
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• pp.19-47
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• 2015

In this era of knowledge economy, a variety of virtual communities are proliferating for the purpose of knowledge creation and utilization. Since the voluntary contributions of members are the essential source of knowledge, member turnover can have significant implications on the survival and success of virtual communities. However, there is a dearth of research on the effect of membership turnover and even the method of measurement for membership turnover is left unclear in virtual communities. In a traditional context, membership turnover is calculated as the ratio of the number of departing members to the average number of members for a given time period. In virtual communities, while the influx of newcomers can be clearly measured, the magnitude of departure is elusive since explicit withdrawals are seldom executed. In addition, there doesn't exist a common way to determine the average number of community members who return and contribute intermittently at will. This study initially examines the limitations in applying the concept of traditional turnover to virtual communities, and proposes five membership fluidity measures based on a preliminary analysis of editing behaviors of 2,978 featured articles in English Wikipedia. Subsequently, this work investigates the relationships between three selected membership fluidity measures and group collaboration performance, reflecting a moderating effect dependent on work characteristic. We obtained the following results: First, membership turnover relates to collaboration efficiency in a right-shortened U-shaped manner, with a moderating effect from work characteristic; given the same turnover rate, the promotion likelihood for a more professional task is lower than that for a less professional task, and the likelihood difference diminishes as the turnover rate increases. Second, contribution period relates to collaboration efficiency in a left-shortened U-shaped manner, with a moderating effect from work characteristic; the marginal performance change per unit change of contribution period is greater for a less professional task. Third, the number of new participants per month relates to collaboration efficiency in a left-shortened reversed U-shaped manner, for which the moderating effect from work characteristic appears to be insignificant.