• Journal of Aquaculture
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• v.20 no.4
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• pp.205-211
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• 2007

Stress-inducible proteins may function in part as molecular chaperones, protecting cells from damage due to various stresses and helping to maintain homeostasis. We examined the mRNA expression patterns of a 68-kDa heat shock protein (HSP68) and 78-kDa glucose-regulated protein (GRP78) in relation to physiological changes in Pacific oyster Crassostrea gigas under osmotic stress. Expression of HSP68 and GRP78 mRNA in the gill significantly increased until 48 h in a hypersaline environment (HRE) and 72 h in a hyposaline environment (HOE), and then decreased. Osmolality and the concentrations of $Na^+$, $Cl^-$, and $Ca^{2+}$ in the hemolymph of HRE oysters significantly increased until 72 h (the highest value) and then gradually decreased; in HOE oysters, these values significantly decreased until 72 h (the lowest value), and then increased. These results suggest that osmolality and $Na^+$, $Cl^-$, and $Ca^{2+}$ concentrations were stabilized by HSP68 and GRP78, and indicate that these two stress-induced proteins play an important role in regulating the metabolism and protecting the cells of the Pacific oysters exposed to salinity changes.

• Restorative Dentistry and Endodontics
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• v.20 no.1
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• pp.342-350
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• 1995

To determine the factors which affect the flow of dentinal fluid through cat dentinal tubules in vivo, the flow of fluid was measured by observing the movement of the fat droplets of dilute milk in a glass capillary with a microscope connected to the monitor. After measuring the exposed area of dentin, hydraulic conductances of dentin were calculated. The mean pressure which stoped the outward flow of dentinal fluid was 9.5mmHg. The hydraulic conductance of dentin under the condition of pulp exposed was increased by 21 % from that under the condition of dentin exposed. Under the conditions of pulp cut and pulp removed, the hydraulic conductances of dentin were increased by 22 % and 31 % respectively from that under the condition of dentin exposed. These results show that the direction and rate of dentinal fluid flow in cat dentin is affected mainly by the hydrostatic pressure of interstitial fluid of pulp tissue in the state of low compliance. Both of the osmotic effect produced by the protein constituents of interstitial fluid across the odontoblast tell layer and the change of interstitial fluid pressure produced by the state of the microcirculation of the pulp also affect the direction and rate of dentinal fluid in some degree.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.321-325
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• 2016

The Pressure Retarded Osmosis (PRO) is the next generation desalination technique and is considered as a eco-friendly energy. This was conducted to evaluate the effect of the temperature and pressure on the PRO performance. The flux of the permeation was measured under different operating conditions and estimated the power density. An improvement of PRO performance is depend on increasing solution temperature and optimum pressure. The effect of increasing feed solution temperature has stronger impact on the PRO performance comparing to the draw solution temperature. The reason of the results was due to the change of osmotic power, viscosity, water permeability and structure parameter(s).

• Journal of the Korean Electrochemical Society
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• v.1 no.1
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• pp.55-59
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• 1998

The water absorption in protective coatings, which may greatly influence the durability of these coatings, was studied using quartz crystal microbalance and electrochemical impedance technique. The water absorption in protective coatings and the change of coating capacitance with concentration of electrolyte were measured. The water absorption in coatings seems to be driven by osmotic pressure, and larger amount of water was absorbed in thinner coatings at initial stage of absorption. The amount of water absorbed in coatings changed with the type and crosslinking density of resin used in coating formulation. When water absorption and desorption of coating occured by exposing the coatings to electrolyte solutions of different concentration, increase in impedance caused by desorption of water was found to be higher in the case of thinner film.

• Korean journal of applied entomology
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• v.26 no.3 s.72
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• pp.145-150
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• 1987

Carborhydrate contents were compared between diapausing and non-diapausing pupae of the fall webworm, Hyphantria cunea DRURY. Glycogen content in the whole body of diapausing pupae kept at $-5{\pm}1^{\circ}C$ was less than that of those left at room temperature, while the amounts of trehalose and sorbitol showed the reverse trend. The osmotic pressure of haemolymph was higher in diapausing pupae than that in non-diapausing pupae. The mean oxygen consumption rate of diapausing pupae was $4{\sim}6.7$ times less than that of non-diapausing, normal pupae.

• Journal of Microbiology and Biotechnology
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• v.32 no.12
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• pp.1547-1552
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• 2022

β-Amyrin is a pentacyclic triterpene widely distributed in leaves and stems worldwide. The ability of β-amyrin to induce the production of reactive oxygen species (ROS) in microorganisms suggests its potential as an antimicrobial agent. Thus, this study aimed to elucidate the antibacterial mode of action of β-amyrin. We treated Escherichia coli cells with β-amyrin and found that it triggered ROS accumulation. Excessive stress caused by ROS, particularly hydroxyl radicals, induces glutathione (GSH) dysfunction. GSH protects cells from oxidative and osmotic stresses; thus, its dysfunction leads to membrane depolarization. The resultant change in membrane potential leads to the release of apoptotic proteins, such as caspases. The activated caspases-like protein promotes the cleavage of DNA into single strands, which is a hallmark of apoptosis-like death in bacteria. Apoptotic cells usually undergo events such as DNA fragmentation and phosphatidylserine exposure, differentiating them from necrotic cells, and the cells treated with β-amyrin in this study were positive for annexin V and negative for propidium iodide, indicating apoptosis-like death. In conclusion, our findings suggest that the antibacterial mode of action of β-amyrin involves the induction of ROS, which resulted in apoptosis-like death in E. coli.

• The Korean Journal of Physiology
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• v.28 no.1
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• pp.79-90
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• 1994

The objective of the present study is to assess the contribution of bulk flow to the regulatory mechanism of amniotic fluid volume and its ionic concentration in the membranes surrounding the amniotic fluid. For quantitative assessment, we prepared 4 kinds of artificial amniotic fIuids (isotonic isovolumetric, hypotonic isovolumetric, isotonic hypervolumetric and hypotonic hypervolumetric ones) by replacing 70% of amniotic fluid of pregnant rabbits with water or normal Tyrode solutions. Isoosmotic saline of 0.5 ml volume containing 0.05% Censored and 15 mM/l LiCl was administered initially into amniotic sacs of all subject animals. Samples of amniotic fluid were collected in after 30 and 90 minute intervals; the concentrations of Censored, $Na^+\;and\;Li^+$ were determined and compared. Followings are the results obtained. 1. from isovolumetric and increased Congcord group, we couldn't find significant change in $Li^+\;and\;Na^+$ concentration in isotonic amniotic fluid. However, $Na^+$ concentration increased significantly as well as a striking increase in Censored concentration in hypotonic amniotic fluid. 2. In isovoIumetric and decreased Censored group, the rate of $[Li^+]$ decrement and the rate of $[Na^+]$ increment were much higher in hypotonic amniotic fluid than in isotonic. 3. In hypervolumetric and increased Censored group, the rate of $Na^+$ efflux increased proportionately with the increment of Censored concentration up to 0.98, which was higher than the rate of $Li^+$ efflux in isotonic amniotic fluid. However, the increment of $Na^+$ concentration was rather related with the initial $Na^+$ concentration in hypotonic amniotic fluid, showing inverse relationship. $Li^+$ concentration increased only when there was a marked increase in Censored concentration and approached near a maximum value or 1. 4. For hypervolumetric and decreased Censored group, the observations were identical to isovolumetric and decreased Censored group. From these results the following conclusions could be made: 1) There is no net movement of water or monovalent cations across the membranes surrounding amniotic fIuid in isotonic isovolumetric condition. In contrast, there is a net efflux of amniotic fluid by osmotic bulk flow, resulting in elevation of $Na^+$ concentration in hypotonic isovolumetric condition. 2) In hypervolumetric conditions, there is a massive efflux of amniotic fluid or solvent drag through the surrounding membranes by fiItrative bulk flow, where the rate of $Na^+$ efflux has a linear relationship with that of water efflux. This is assumed to be carried out through enlarged and newly opened intercellular spaces resulting from increased intraamniotic pressure. 3) Once increasing intraamniotic pressure reaches a point allowing $Li^+$ to pass through during osmotic bulk flow in hypotonic amniotic fIuid, $Na^+$ influx seems to occur by diffusion simultaneously or immediately thereafter, too.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.23 no.3
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• pp.103-108
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• 2012

Objectives : The aim of this study is to investigate the effectiveness of treatment with osmotic-release oral system methylphenidate (OROS-MPH) on quality of life (QOL) in children with attention-deficit hyperactivity disorder (ADHD). Another aim is to assess the relationship between change in QOL and other factors including children's symptoms and academic performance or parents' depression and parenting stress. Methods : A total of 111 medication-naive children with ADHD in a multicenter, open-label, 12-week trial of OROS-MPH completed an evaluation using diverse rating scales at two time points; at baseline and after 12 weeks of treatment. Scales for investigation of children included the Parent Report Form-Children's Health and Illness Profile-Children's Edition (PRF-CHIP-CE) on QOL, the ADHD Rating Scale-IV on symptoms, and the Academic Performance Rating Scale (APRS). The Beck Depression Inventory and Parenting Stress Index were used for assessment of their parents. Results : Total scores for mean PRF-CHIP-CE increased from $207.9{\pm}26.7$ at baseline to $226.3{\pm}25.9$ after 12 weeks of treatment (p<.001). The change of APRS showed the strongest correlation with the increment of PRF-CHIP-CE scores (Pearson coefficient=0.561, p<.001), even after controlling for other factors (partial correlation coefficient=0.420, p<.001). Conclusion : Treatment with MPH-OROS results in improvement of QOL in children with ADHD in Korea. The advance in academic performance plays a key role in this change of QOL.

• Journal of Korean Society of Forest Science
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• v.61 no.1
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• pp.8-14
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• 1983

This study was to diagnose the ontogenetic ability of drought tolerance in trees, and was to investigate the seasonal changes in tissue-water relations parameters, ${\pi}_o$, ${\pi}_p$, $E_{max}$, $N_s/DW$, $V_o/W_s$ and $RWC_{(tlp)}$, obtained from P-V curves on the Pinus koraiensis and Abies holophylla shoots. The results obtained are as follows; 1) Seasonal changes of original osmotic pressure at maximum turgot, ${\pi}_o$, were -1.2 to -1.6 MPa in Pinus koraiensis and -1.4 to -1.7 MPa in Abies holophylla. 2) Seasonal changes of osmotic pressure at incipient plasmolysis, ${\pi}_p$, were -1.8 to -2.1 MPa in Pinus koraiensis and -1.6 to -2.1 MPa in Abies holophylla. 3) Seasonal changes of relative water content at incipient plasmolysis, $RWC_{(tlp)}$, were 70 to 77% in Pinus koraiensis and 69 to 85% in Abies holophylla. 4) Seasonal changes of maximum bulk modulus of elasticity at maximum hydration, $E_{max}$, were 2.2 to 6.3 MPa in Pinus koraiensis and 3.1 to 7.9 MPa in Abies holophylla. 5) Seasonal changes of number of osmoles of solute in symplasm versus dry weight, $N_s/DW$, were 0.5 to 1.3 in Pinus koraiensis and 0.3 to 1.0 in Abies holophylla. 6) Seasonal changes of original osmotic water volume versus total water volume (symplasmic and apoplastic water), $V_o/W_s$, were 55 to 65%r in Pinus koraiensis and 40 to 65% in Abies holophylla. Consequently, as the comparative values of ${\pi}_o$, ${\pi}_p$, $E_{max}$, $N_s/DW$, $V_o/W_s$, and $RWC_{(tlp)}$, it might be suggested that Abies holophylla shoot could have more or less a greater ability of drought tolerance as compared with Pinus koraiensis shoot.

• BMB Reports
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• v.30 no.6
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• pp.379-384
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• 1997

The effects of several ions on the specific activity and isozyme patterns of cellular and secretory isoperoxidases were studied in suspension-cultured cells of rice (Oryza sativa L.). Peroxidase release into the culture medium occurred in the absence of added calcium. The addition of calcium ion greatly stimulated the secretion of cationic isoperoxidases such as C2 and C3 into the medium: a maximum 11 fold increase of secretions occurred in the presence of 5 mM $CaCl_2$, and the secretion was accomplished within 1 hour after the addition of $CaCl_2$. About a 10 fold increase of the peroxidase secretion into the medium did occur with 0. 5% NaCl, whereas cellular isoperoxidase levels were reduced notably. About a 6 fold increase of the specific activity of cellular isoperoxidase was found in 5 mM $NiCl_2$-treated cell, while $NiCl_2$ had no effect on the secretion of peroxidase into the medium. Various concentrations of KCl did not change peroxidase secretion, but 5 mM $ZnCl_2$ reduced peroxidase secretion greatly. The major secretory isoperoxidases stimulated by $CaCl_2$, NaCl and cellulase were composed of cationic isoperoxidases C2 and C3, which were found to be localized in the cell wall of rice by examination of the enzyme in the protoplast. Furthermore, the secretion rates of secretory isoperoxidases were increased rapidly when cellulase was treated in the absence of the osmotic stabilizer of 0.4 M mannitol. These results suggest that the stimulations of secretory isoperoxidase levels seem to be due to the stimulation of secretion into the culture medium of rice.