• The Korean Journal of Physiology and Pharmacology
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• 제3권1호
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• pp.59-68
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• 1999

Chemically induced hypoxia has been shown to induce a depletion of ATP. Since intracellular free $Mg^{2+}\;([Mg^{2+}]_i)$ appears to be tightly regulated following cellular energy depletion, we hypothesized that the increase in $[Mg^{2+}]_i$ would result in $Mg^{2+}$ extrusion following hormonal stimulation. To determine the relation between $Mg^{2+}$ efflux and cellular energy state in a hypoxic rat heart and isolated myocytes, $[Mg^{2+}]_i,$ ATP and $Mg^{2+}$ content were measured by using mag-fura-2, luciferin-luciferase and atomic absorbance spectrophotometry. $Mg^{2+}$ effluxes were stimulated by norepinephrine (NE) or cAMP analogues, respectively. $Mg^{2+}$ effluxes induced by NE or cAMP were more stimulated in the presence of metabolic inhibitors (MI). Chemical hypoxia with NaCN (2 mM) caused a rapid decrease of cellular ATP within 1 min. Measurement of $[Mg^{2+}]_i$ confirmed that ATP depletion was accompanied by an increase in $[Mg^{2+}]_i.$ No change in $Mg^{2+}$ efflux was observed when cells were incubated with MI. In the presence of MI, the cAMP-induced $Mg^{2+}$ effluxes were inhibited by quinidine, imipramine, and removal of extracellular $Na^+.$ In addition, after several min of perfusion with $Na^+-free$ buffer, a large increase in $Mg^{2+}$ efflux occurred when $Na^+-free$ buffer was switched to 120 mM $Na^+$ containing buffer. A similar $Mg^{2+}$ efflux was observed in myocytes. These effluxes were inhibited by quinidine and imipramine. These results indicate that the activation of $Mg^{2+}$ effluxes by hormonal stimulation is directly dependent on intracellular $Mg^{2+}$ contents and that these $Mg^{2+}$ effluxes appear to occur through the $Na^+-dependent\;Na^+/Mg^{2+}$ exchange system during chemical hypoxia.

• Journal of Pharmaceutical Investigation
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• 제38권5호
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• pp.295-302
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• 2008

In the present study, we examined the changes of uptake and efflux of taurine under various conditions inducing oxidative stress using rat conditionally immortalized syncytiotrophoblast cell line, TR-TBT cell, as blood-placental barrier in vitro model. In addition, we identified the characteristics of taurine transport in TR-TBT cells including general features, besides effect of calcium ion on taurine transport. Taurine uptake showed time, $Na^+$ and $Cl^-$ dependency, and was decreased by PKC activator in TR-TBT cells. Also, calcium free condition decreased taurine uptake and evoked taurine efflux in the cells. Oxidative stress induced the change of taurine transport in TR-TBT cells, but the changes were different depending on the types of stimulation inducing oxidative stress. The taurine uptake was increased by TNF-$\alpha$, LPS and DEM stimulation but decreased by $H_2O_2$ and NO stimulation. Also, the taurine efflux was regulated by TNF-$\alpha$ stimulation. In conclusion, the taurine transport through the blood-placental barrier was regulated in oxidative stress conditions, and these results demonstrated that oxidative stress affected the taurine supplies to fetus and taurine level of fetus.

• The Korean Journal of Physiology
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• 제12권1_2호
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• pp.1-5
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• 1978

In an attempt to explore the effect of Ginseng on the permeability of the biological membrane to cations we have investigated the effect of Ginseng-alcohol extract on the transport of $Na^+$ human red blood cell preprations. The $Na^+$ influx was measured in intact red cells using $^{22}Na$ as a tracer and the efflux in reseated red cells using $^{24}Na$ as a tracer. 1. The influx of $Na^+$ was not apparently changed by the Ginseng-alcohol extract of 20mg% in the incubation medium. 2. Similarly, 20mg% Ginseng-alcohol extract in the cellular space did not alter the efflux of $Na^+$ from the cell. However, 50mg% of Ginseng-alcohol extract in the cell resulted in a significant increase in the $Na^+$ efflux and this effect was magnified when the cell was suspended in the medium containing the Ginseng-alcohol extract in a concentration of 20mg %. The results suggest that Ginseng-alcohol extract over 50mg% increase permeability of red blood cell membrane to $Na^+$ by altering the membrane integrity.

• 한국농림기상학회지
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• 제18권3호
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• pp.120-126
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• 2016

본 연구는 유사한 입지에서 생육한 소나무와 굴참나무 임분의 토양 이산화탄소($CO_2$)와 이들 방출에 영향을 미치는 환경요인인 토양 온도, 토양 수분, 토양 pH, 전기전도도, 토양 유기탄소 농도 등을 2015년 3월부터 2016년 2월까지 1년 동안 조사하였다. 토양 $CO_2$ 방출량의 월별 변화는 두 임분 사이에 차이가 있어 하절기인 6월과 7월의 경우, 굴참나무 임분이 소나무 임분에 비해 유의적으로 높았으나, 타 계절은 차이가 없었다. 연 평균 토양 $CO_2$ 방출량의 경우, 굴참나무 임분이 $2.27{\pm}0.22{\mu}mol\;m^{-2}s^{-1}$로 소나무 임분의 $1.63{\pm}0.12{\mu}mol\;m^{-2}s^{-1}$ 에 비해 높게 나타났으며, 연 평균 토양 온도와 토양 수분함량도 굴참나무 임분이 소나무 임분에 비해 높았다. 토양 환경요인 중 토양 온도와 토양 $CO_2$ 방출량은 지수함수 관계(P<0.05)가 있었으며, $Q_{10}$ 값의 경우, 굴참나무 임분이 3.35로 소나무 임분 2.72에 비해 높아 토양 온도 상승 시, 굴참나무 임분의 토양 $CO_2$ 방출량이 소나무 임분에 비해 더 크게 증가하는 것으로 나타났다.

• The Korean Journal of Physiology and Pharmacology
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• 제1권6호
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• pp.717-730
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• 1997

$Mg^{2+}$ is the fourth most abundant cation in cellular organisms. Although the biological chemistry and the physiological roles of the magnesium ion were well known, the regulation of intracellular $Mg^{2+}$ in mammalian cells is not fully understood. More recently, however, the mechanism of $Mg^{2+}$ mobilization by hormonal stimulation has been investigated in hearts and in myocytes. In this work we have investigated the regulation mechanism responsible for the $Mg^{2+}$ mobilization induced by ${\alpha}1-adrenoceptor$ stimulation in perfused guinea pig hearts or isolated myocytes. The $Mg^{2+}$ content of the perfusate or the supernatant was measured by atomic absorbance spectrophotometry. The elimination of $Mg^{2+}$ in the medium increased the force of contraction of right ventricular papillary muscles. Phenylephrine also enhanced the force of contraction in the presence of $Mg^{2+}$-free medium. ${\alpha}1-Agonists$ such as phenylephrine were found to induce $Mg^{2+}$ efflux in both perfused hearts or myocytes. This was blocked by prazosin, a ${\alpha}1-adrenoceptor$ antagonist. $Mg^{2+}$ efflux by phenylephrine was amplified by $Na^+$ channel blockers, an increase in extracellular $Ca^{2+}$ or a decrease in extracellular $Na^+$. By contrast, the $Mg^{2+}$ influx was induced by verapamil, nifedipine, ryanodine, lidocaine or tetrodotoxin in perfused hearts, but not in myocytes. $W_7$, a $Ca^{2+}/calmodulin$ antagonist, completely blocked the pheylephrine-, A23187-, veratridine-, $Ca^{2+}-induced$ $Mg^{2+}$ efflux in perfused hearts or isolated myocytes. In addition, $Mg^{2+}$ efflux was induced by $W_7$ in myocytes but not in perfused heart. In conclusion, An increase in $Mg^{2+}$ efflux by ${\alpha}1-adrenoceptor$ stimulation in hearts can be through $IP_3$ and $Ca^{2+}-calmodulin$ dependent mechanism.

• 한국습지학회지
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• 제20권2호
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• pp.116-123
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• 2018

산림생태계에서 대기로의 토양의 이동은 토양 호흡이라는 과정을 통해 이루어진다. 본 연구에서는 임령이 다른 잣나무림을 대상으로 생육기 동안의 토양 호흡값과 토양 내 뿌리의 양, 미생물 개체군 생물량을 측정하여, 토양호흡량이 임령에 따라 어떻게 다르며, 뿌리와 미생물 개체군이 얼마나 기여할 것인지 알아보고자 하였다. 토양 온도와 토양 호흡은 임령과는 상관없이 유사한 패턴을 보여 7월까지는 증가하고 이후 감소하였다. 산림의 임령이 높을수록 토양 호흡량이 대체적으로 높았다. 토양 내 뿌리와 미생물을 조사한 결과, 임령이 높을수록 토양 내 존재하는 지름 2 mm 이하인 세근의 양이 많았으며 토양 미생물 개체군의 생물량이 많았다. 토양에서 뿌리를 제거하였을 때 70년 숲은 변화가 없었으나, 40년 숲에서는 토양 호흡값이 감소하였다. 본 연구결과로 볼 때, 산림의 연령이 높아질수록 토양 호흡량이 커지며, 식물 뿌리와 특히 토양 미생물이 토양 호흡값에 많은 기여를 하고 있는 것으로 생각해 볼 수 있다.

• 한국산림과학회지
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• 제105권1호
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• pp.12-18
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• 2016

경남 진주시의 남부산림자원연구소 월아시험림 내 소나무재선충병 발생 곰솔임분의 간벌 처리구를 대상으로 토양 이산화탄소($CO_2$) 방출량과 토양환경요인 변화를 조사하기 위하여 강도구, 약도구, 대조구를 설치하고 2012년 3월부터 2013년 2월까지 토양 $CO_2$ 방출량, 토양온도, 토양수분함량, 토양 pH 변화를 조사하였다. 토양 $CO_2$ 방출량의 월별 변화는 간벌처리구와 대조구 사이에 유의적 차가 없었다(P>0.05). 연 평균 토양 $CO_2$ 방출량의 경우 처리간 유의적인 차는 없었으나 약도구 $0.58g\;CO_2m^{-2}h^{-1}$, 강도구 $0.49g\;CO_2m^{-2}h^{-1}$, 대조구 $0.45g\;CO_2m^{-2}h^{-1}$ 순으로 약도구가 높게 나타났다. 토양 $CO_2$ 방출량은 토양온도와 유의적인 지수함수 관계(P<0.05)가 있었으나 토양수분과 토양 pH 와는 유의적인 상관관계가 없었다(P>0.05). $Q_{10}$ 값의 경우 약도구 3.40, 강도구 3.20, 대조구 3.06으로 약도구가 가장 크게 나타나 소나무재선충병 발생 곰솔임분의 간벌처리는 토양온도 상승과 함께 토양 $CO_2$ 방출에 영향을 미치는 것으로 나타났다.

• 한국축산시설환경학회지
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• 제1권1호
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• pp.55-64
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• 1995

본 연구는 최근 개발된 광합성세균(Rhodopseudomonas capsulata)을 이용한 연속적 폭기식 생물 반응조(이하 CABR)를 이용한 무희석 양돈 분뇨의 처리 결과를 보고하고 있다. CABR를 이용하여 24시간 동안 양돈 분뇨를 폭기 처리한 결과 유입량의 40%가 증발되었고, 유입분뇨의 전체 BOD, COD중 87%, 32%가 각각 제거되었으며, 전질소(T-N), 전인(T-P)은 각각 110%, 112%로 증가되었다. CABR 배출액의 질소 형태를 분석한 결과 암모니아성 질소($NH_4-N$) 농도는 저하된 반면, 유기태 질소(Org-N)농도는 증가하였다. 양돈분뇨의 주요 BOD원이며 악취의 주요물질인 저급지방산은 CABR의 처리결과 거의 제거 되었다. 한편 CABR 배출액의 유기액비로서의 이용성을 검토하였다. CABR 배출액은 식물성장에 필요한 질소, 인산, 칼리의 함량이 비교적 균형있게 포함되어 있으며, 특히 질소의 86%는 유기태질소(Org0N)로 되어 있어 완효성 비료로서의 이용 가능성이 시사되었다. 또한 중금속의 함량도 낮아 위해성의 문제는 없는 것으로 밝혀졌다. 이탈리안 라이그라스(목초)의 토경재배 실험결과 일반화학비료에 비해 생육량이 증가되었으며, 특히 질산태질소($NO_3-N$)의 작물내 함유량이 매우 낮았다. 이러한 결과는 CABR 배출액이 농작물 생산에 매우 적합한 유기액비로서 이용할 수 있음을 시사하고 있다.

• The Korean Journal of Physiology
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• 제8권1호
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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 Plant Pathology Journal
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• 제36권2호
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• pp.148-156
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• 2020

Pseudomonas syringae pv. tabaci 6605 has two multidrug resistance (MDR) efflux pump transporters, MexAB-OprM and MexEF-OprN. To understand the role of these MDR efflux pumps in virulence, we generated deletion mutants, ΔmexB, ΔmexF, and ΔmexBΔmexF, and investigated their sensitivity to plant-derived antimicrobial compounds, antibiotics, and virulence. Growth inhibition assays with KB soft agar plate showed that growth of the wild-type (WT) was inhibited by 5 μl of 1 M catechol and 1 M coumarin but not by other plant-derived potential antimicrobial compounds tested including phytoalexins. The sensitivity to these compounds tended to increase in ΔmexB and ΔmexBΔmexF mutants. The ΔmexBΔmexF mutant was also sensitive to 2 M acetovanillone. The mexAB-oprM was constitutively expressed, and activated in the ΔmexF and ΔmexBΔmexF mutant strains. The swarming and swimming motilities were impaired in ΔmexF and ΔmexBΔmexF mutants. The flood inoculation test indicated that bacterial populations in all mutant strains were significantly lower than that of WT, although all mutants and WT caused similar disease symptoms. These results indicate that MexAB-OprM extrudes plant-derived catechol, acetovanillone, or coumarin, and contributes to bacterial virulence. Furthermore, MexAB-OprM and MexEF-OprN complemented each other's functions to some extent.