• The Korean Journal of Physiology and Pharmacology
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• v.11 no.5
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• pp.175-182
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• 2007

Members of prostaglandin(PG) E-series elicit cellular effects mainly through adenylyl cyclase-cAMP signaling. The role of $PGE_2$-induced increase in cAMP has been shown to be compartmentalized in the cardiac myocytes: $PGE_2$-induced increase of cAMP is not involved in the control of cardiomyocytic contraction. The purpose of the present study was to define the effect of $PGE_1$ on the cGMP levels and the role of $PGE_1$ in the atrial secretory function. Experiments were performed in perfused beating rabbit atria and atrial contractile responses, cGMP and cAMP efflux, and atrial natriuretic peptide(ANP) secretion were measured. $PGE_1$ increased cGMP as well as cAMP efflux concentration in a concentration-dependent manner, however, no significant changes in atrial secretory responses were observed(with $1.0{\mu}M\;PGE_1$; for cGMP, $144.76{\pm}37.5%$, n=11 versus $-16.81{\pm}4.76%$, n=6, control, p<0.01; for cAMP, $187.60{\pm}41.52%$, n=11 versus $7.38{\pm}19.44%$, n=6, control, p<0.01). $PGE_1$ decreased atrial dynamics slightly but transiently, whereas $PGE_2$ showed similar effects but with lower potency. Isoproterenol increased atrial cAMP efflux(with 2.0 nM; $145.71{\pm}41.89$, n=5 versus $7.38{\pm}19.44%$, n=6, control, p<0.05) and mechanical dynamics and decreased ANP secretion. The $PGE_1$-induced increase in cGMP efflux showed a bell-shaped concentration-response curve. $PGE_1$-induced increase of cGMP efflux was not observed in the presence of L-NAME, an inhibitor of nitric oxide(NO) synthase, or ODQ, an inhibitor of NO-sensitive guanylyl cyclase. L-NAME and ODQ showed no significant effect on the $PGE_1$-induced transient decrease of atrial dynamics. These data indicate that $PGE_1$ increases cGMP levels via NO-soluble GC signaling in the cardiac atrium and also show that $PGE_1$-induced increases in cGMP and cAMP levels are not involved in the regulation of atrial secretory and contractile functions.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.12-18
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• 2016

This study was carried out to investigate the change on soil $CO_2$ efflux rates, soil temperature, soil water content and soil pH by thinning intensity treatments (heavy thinning, light thinning, control) of a black pine (Pinus thunbergii Parl.) stand disturbed by pine wilt disease in Wola National Experimental Forests in Jinju, Gyeongnam province. Monthly variations of soil $CO_2$ efflux rates were not significantly different between the thinning and the control treatments (P>0.05). The annual mean soil $CO_2$ efflux rates were $0.58g\;CO_2m^{-2}h^{-1}$ for the light thinning, $0.49g\;CO_2m^{-2}h^{-1}$ for the heavy thinning and $0.45g\;CO_2m^{-2}h^{-1}$ for the control treatments, respectively. There was a significant exponential relation between soil $CO_2$ efflux rates and soil temperature, but no correlation between soil water content or soil pH and soil $CO_2$ efflux rates. The values of $Q_{10}$ were 3.40 for the light thinning, 3.20 for the heavy thinning and 3.06 for the control treatments, respectively. The results indicate that soil $CO_2$ efflux rates in a black pine stand disturbed by pine wilt disease could be affected by thinning treatments.

• The Korean Journal of Physiology
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• v.8 no.1
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• pp.45-53
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• 1974

The effects of kanendomycin on the potassium permeability in the rabbit erythrocyte membrane are investigated and the results are summarized as follows. 1. Kanendomycin causes the efflux of $K^+\;and\;influx\;of\;Na^+$ across the rabbit erythrocyte membrane. 2. Osmotic resistance of kanendomycin treated erythrocytes is diminished. This diminution of osmotic resistance is more pronounced by increasing concentration of kanendomycin and longer incubation time. But osmotic resistance is rather increased in the presence of lower concentration of kanendomycin. 3. Cysteine and glutathione have little influence on $K^+$ efflux induced by kanendomycin. 4. EDTA has no effect on the increase in $K^+$ outflux by kanendomycin while PCMB augments slightly on $K^+$ outflux. 5. Kanendomycin inhibits $Ca^{++}$ binding competitively to rabbit erythrocyte membrane fragments.

• The Korean Journal of Ecology
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• v.1 no.1
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• pp.3-10
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• 1977

The sigmoiod kinetics of mass-action in a biosystem have been studied by theoretical bases on the carrier hypothesis of influx and efflux of substrates. The sigmoid kinetic equations of assimilation and dissimilation rates indicate that each trophicfactor and each bio-factor behave according to the sigmoid kinetic equation and the bell shape case, and all of them are multiplicative. The general sigmoid kinetics of mass-action is given by the equation (30) which is determined by the total of the equation (28) of the assimilation rate and the equation (29) of the dissimilation rate. The sigmoid kinetic model of photosynthesis has been derived from the general equation of the sigmoid kinetics of mass-action.

• Journal of Ocean Engineering and Technology
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• v.11 no.1
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• pp.55-64
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• 1997

A wing operating in close proximity to the ground exhibits a reduction in induced drag, which increase the lift/drag ratio. The poert-augmented ram (RAR) phenomenon involves directiing the efflux from forward mounted propulsion ststem under the wings, with the efflux nearly stagnated under the wings. In the present paper, 3 dimentional PAR was numerically studied by solving the Navier-Stokes equations. Pressure distribution and velocity vectors are calculated around the wing surface and the ground. Through the numerical simulation, Cp values and lift/drag ratio are carefully reviewed by changing the height/chord; 0.05, 0.1, 0.3 and 0.8. The shape of model is NACA 0012 with a span/chord ratio of 3.0. According to the numerical results, the relationship between lift/drag and height/chord is fairly reasonable.

• Journal of Integrative Natural Science
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• v.5 no.2
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• pp.72-78
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• 2012

Multidrug resistance is a major obstacle in cancer chemotherapy. Cancer cells efflux chemotherapeutic drug out of cell by means of transporter and reduce the active concentration of it inside cell. Such transporters are member of the ATP binding cassettes (ABC) protein. It includes P-gp, multiple resistant protein (MRP), and breast cancer resistant protein (BCRP). These proteins are widely distributed in the human cells such as kidney, lung, endothelial cells of blood brain barrier etc. However, there are number of drugs developed for it, but most of them are getting transported by it. So, still there is necessity of a good modulator, which could effectively combat the transport of chemotherapeutic agents. Natural products origin modulators were found to be effective against transporter such as flavonoids, which belongs to third generation modulators. They have advantage over synthetic inhibitor in the sense that they have simple structure and abundant in nature. This review focuses on the P-gp structure its architecture, efflux mechanism, herbal inhibitors and their mechanism of action.

• BMB Reports
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• v.28 no.6
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• pp.552-555
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• 1995

Treatment of microsomal vesicles isolated from etiolated Pisum sativum L cv. Alaska epicotyl tissue with agents inhibiting protein dephosphorylation, namely NaF and/or ATP, resulted in increased binding of the phytotropin NPA to the putative auxin efflux carriers localized on the plasma membrane. The phytotropin effect was especially conspicuous if the vesicles were simultaneously treated with Triton X-100. Kinetic analysis of the binding indicated the existance of two distinct sites for NPA, each having different affinities. Increased binding of the phytotropin to the membrane where protein dephosphorylation was inhibited was attributable to the increased ligand affinity of both sites. Treatment of tissue segments with flubride was found to enhance in vivo auxin transport. Implications of covalent modification of the auxin efflux carrier complex for the regulation of membrane transport of auxin molecules are discussed.

• The Korean Journal of Ecology
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• v.20 no.2
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• pp.83-94
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• 1997

Stomatal closing by ozone and water stress could reduce further ozone injury by inhibition of ozone influx to the tissue. Direct effect of ozone on stomata can be explained from two aspects which are a stimulation of stomatal closing and an inhibition of stomatal opening. An increase of $Ca^{2+}$ influx into cytoplasm by ozone could stimulate potassium efflux ion channel and inhibits inward potassium ion channels. By this mechanism ozone could induce stomatal closing. On the other hand, ozone could inhibit stomatal opening by affecting the activity of $H^{+}$ dependent ATPase of the membrane in guard cells. This would inhibit proton efflux which precede stomatal opening. It is also possible that ozone could reduce the activity of photosynthesis in guard cells which lead to affect the production of osmotically active sugars and energy. Indirect effect of ozone to stomata is through the effect of $CO_2$ elevation as a result of damage of the photozynthetic machinery. This indirect effect is slower than the direct effect.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.77-77
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• 1998

No Abstract, See Full Text

• BMB Reports
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• v.35 no.1
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• pp.41-46
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• 2002