• 한국환경보건학회지
• /
• 제26권4호
• /
• pp.88-96
• /
• 2000

The aim of the current study was to evaluate the transport system in EMT-6 cell for the uptake of the methylmercury(MeHg). Several inhibitors ere used to test used to test which potential transport system might be involoved in MeHg uptake. Probenecid was used to test the organic transport system, valinomycin for testing the effect of the membrane potential, cytochalasin B for testing the facilitated diffusive D-glucose transport system and colchicine for testing the microtubule system. Ouabain for evaluating active transport system, 4',4-diisothiocyano-2',2-stilbenedisulfonic acid(DIDS) the Cl- ion transport system and verapamil for the $Ca^{2+}$ transprot system. Significantly, MeHg decreased the synthesis of nitric oxcide(NO) and intracellular ATP in ENT-6 cells. In the condition of ouabain containing with MeHg decreased the production of NO and intracelluar ATP. In the treatment of inhibitors, ouabain showed protective effect against cytotoxicity of MeHg but ather inhibitors not showed protective effects. The protective effects of ouabain against the cytotoxicity of MeHg deoended on the concentration of added ouabain to the culture medium for MET-6 cells. These result showed that the uptake of MeHg might be involved in the active transport system. Active transports system seems to share similarities with the transport systems for the uptake of MeHg when using MeHg and MeHg-glutathione complex.x.

• Journal of Pharmaceutical Investigation
• /
• 제34권2호
• /
• pp.101-106
• /
• 2004

This work aims at examining the cellular uptake behavior of poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles derivatized with a protein transduction domain (PTD) using HeLa cells. For this purpose, $Tat_{49-57}$ peptide derived from transcriptional activation (Tat) protein of HIV type-1 was covalently conjugated to the terminal end of PLGA. Nanoparticles were ten prepared with the $Tat_{49-57}-PLGA$ conjugates by a spontaneous phase inversion method. The prepared particles had a mean diameter of ca. 84 nm, as measured by dynamic light scattering. The interaction of the Tat-PLGA nanoparticles with cells was examined by using confocal laser scanning microscopy. It was found tat Tat-PLGA nanoparticles incubated with HeLa cells could efficiently translocate into cytoplasm, while plain PLGA nanoparticles showed negligible cellular uptake. In addition, even at $4^{\circ}C$ or in the presence of sodium azide significant cellular internalization of Tat-PLGA nanoparticles was still observed. These results indicate that a non-endocytotic translocation mechanism might be involved in the cellular uptake of Tat-PLGA nanoparticles.

• Archives of Pharmacal Research
• /
• 제20권1호
• /
• pp.7-12
• /
• 1997

Glutamate uptake inhibitor, L-trans-pyrrolidine-2, 4-dicarboxylate (PDC, $20{\mu}M$) elevated basal and N-methyl-D-aspartate (NMDA, $100{\mu}M$)-induced extracellular glutamate accumulation, while it did not augment kainate $100{\mu}M$-induced glutamate accumulation in cultured cerebellar granule neurons. However, pretreatment with PDC for 1 h significantly reduced NMDA-induced glutamate accumulation, but did not affect kainate-induced response. Pretreatment with glutamate $(5{\mu}M)$ for 1 h also reduced NMDA-induced glutamate accumulation, but did not kainate-induced response. Upon a brief application (3-10 min), PDC did neither induce elevation of intracellular calcium concentration $([Ca^{2+}]_i)$ nor modulate NMDA-indLiced $[Ca^{2+}]_1$ elevation. Pretreatment with PDC for 1 h reduced NMDA-induced $[Ca^{2+}]_1$ elevation, but it did not reduce kainate-induced $[Ca^{2+}]_1$ elevation. These results suggest that glutamate concentration in synaptic clefts of neurana cells is increased by prolonged exposure (1 h) of the cells to PDC, and the accumulated glutamate subsequently induces selective desensitization of NMDA receptor.

• 약학회지
• /
• 제48권6호
• /
• pp.352-357
• /
• 2004

Atrial myocytes have two functionally separate groups of ryanodine receptors (RyRs): those at the periphery colocalized with L-type $Ca^{2+}$channels (DHPRS) and those a t the cell interior not associated with DHPRs. $Ca^{2+}$ current ($I_{ca}$) directly gates peripheral RyRs on action potential and the subsequent peripheral $Ca^{2+}$ release propagates into the center of atrial myocytes. The mechanisms that regulate the $Ca^{2+}$+ propagation wave remain Poorly understood. Using 2-D confocal$Ca^{2+}$ imaging, we examined the role of inositol 1,4,5-trisphosphate receptor (IP $_3R$) and mitochondria on ($I_{ca}$)- gated local $Ca^{2+}$ signaling in rat atrial myocytes. Blockade of IP $_3R$ by xestospongin C (XeC) partially suppressed the magnitudes of I ca-gated central and peripheral $Ca^{2+}$ releases with no effect on $I_{ca}$. Mitochondrial staining revealed that mitochondria were aligned with ${\thickapprox}2-{\mu}m$ separations in the entire cytoplasm of ventricular and atrial myocytes. Membrane depolarization induced rapid mitochondrial $Ca^{2+}$ rise and decay in the cell periphery with slower rise in the center, suggesting that mitochondria may immediately uptake cytosolic $Ca^{2+}$, released from the peripheral SR on depolarization, and re-release the $Ca^{2+}$ into the cytosol to activate neighboring central RyRs. Our data suggest that the activation of IP $_3R$ and mitochondrial $Ca^{2+}$ handing on action potential may serve as a cofactor for the $Ca^{2+}$ propagation from the DHPR-coupled RyRs to the DHPR-uncoupled RyRs with large gaps between them.

• The Korean Journal of Ecology
• /
• 제24권1호
• /
• pp.51-59
• /
• 2001

1995년부터 1999년까지의 임업통계 자료를 사용하여 남한 삼림에서의 연순생산량과 질소(N) 및 염기성 양이온 (BC=K, Mg, Ca)의 흡수량을 추정하였다. 줄기와 가지의 연순생산량은 약 1.8 ton DM h $a^{-1}$ y $r^{-1}$이었으며 침엽수림에 비해 활엽수림의 연순생산량이 높게 나타났다. 삼림 전체 면적인 6.246$\times$106 ha에서 전 연순생산량은 약 1.13$\times$$10^{7}$ ton DW/yr 이었다. 1999년의 용재생산량으로 추정한 남한 삼림에서 줄기와 가지의 수확량은 약 6.1$\times$$10^{5}$ ton DW/yr 이었으며 단위 면적당 수확량은 98 kg DM h $a^{-1}$ y $r^{-1}$이었다. 한편, 생장에 의한 N과BC의 흡수량은 각각 350 mol h $a^{-1}$y sup -1/와 296 mol h $a^{-1}$ y $r^{-1}$이었고, 수확량에 포함된 N과 BC의 양은 각각 20mol h $a^{-1}$ y $r^{-1}$와 16 mol h $a^{-1}$ y $r^{-1}$로 BC에 비해 N의 흡수량이 높게 나타났다. 남한의 전 삼림에서 생장과 수확에 의한 N과 BC의 총 흡수량은 각각 2.309$\times$$10^{9}$ mol/yr와 1.953$\times$$10^{9 mol}$yr 이었다.

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 1997년도 한국생물과학협회 학술발표대회
• /
• pp.219.2-219
• /
• 1997

No Abstract, See Full Text

• 한국토양비료학회지
• /
• 제46권5호
• /
• pp.351-358
• /
• 2013

A suitable supply of mineral elements into shoot via a root system from growth media makes plants favorable growth and yield. The shortage or surplus of minerals directly affects overall physiological reactions to plants and, especially, strongly influences carbohydrate metabolism as a primary response. We have studied mineral uptake and synthesis and translocation of soluble carbohydrates in N, P or K-deficient tomato plants, and examined the interaction between soluble carbohydrates and mineral elements. Four-weeks-old tomato plants were grown in a hydroponic growth container adjusted with suboptimal N ($0.5mmol\;L^{-1}\;Ca(NO_3)2{\cdot}4H_2O$ and $0.5mmol\;L^{-1}\;KNO_3$), P ($0.05mmol\;L^{-1}\;KH_2PO_4$), and K ($0.5mmol\;L^{-1}\;KNO_3$) for 30 days. The deficiency of specific mineral element led to a significant decrease in its concentration and affected the concentration of other elements with increasing treatment period. The appearance of the reduction, however, differed slightly between elements. The ratios of N uptake of each treatment to that in NPK sufficient tomato shoots were 4 (N deficient), 50 (P deficient), and 50% (K deficient). The P uptake ratios were 21 (N deficient), 19 (P deficient), and 28% (K deficient) and K uptake ratios were 11 (N deficient), 46 (P deficient), and 7% (K deficient). The deficiency of mineral elements also influenced on carbohydrate metabolism; soluble sugar and starch was substantially enhanced, especially in N or K deficiency. In conclusion, mineral deficiency leads to an adverse carbohydrate metabolism such as immoderate accumulation and restricted translocation as well as reduced mineral uptake and thus results in the reduced plant growth.

• 한국약용작물학회지
• /
• 제20권3호
• /
• pp.195-201
• /
• 2012

The management and the use of major mineral nutriments such as nitrogen, phosphorous, and potassium, etc have been practiced and improved in various cultivating methods of Panax ginseng C. A. Meyer. The purposes of this study were to examine the content of major mineral nutrients on different ginseng aging from 1 to 6 years old, to analyze their uptake and utilization in tissues of ginseng, and to find out their proper managing techniques throughout the cultivation of ginseng. In case of the leaves, the N content was not clearly different from 1 to 6 years old, while the content of P and K was generally decreased throughout the cultivating years. In case of the roots, the content of N and K was gradually decreased from 1 to 6 years old, while the P content was increased until 3 years old, decreased at 4 years old, increased again at 5 years old, and decreased again at 6 years old. The uptake amount of N was increased in root of ginseng from 1 to 6 years old, 0.02 to 2.79kg/10a based on dry weight, respectively. Other minerals of P, K, Ca, and Mg were increased for the cultivating year. Comparing the uptake amounts of N, P, K with different cultivating year, they were the highest uptake amount at 4 years old and then were decreased. The management techniques of major mineral in cultivation of ginseng would be studied and evaluated more in order to have better ginseng production.

• The Korean Journal of Physiology
• /
• 제29권2호
• /
• pp.225-232
• /
• 1995

The present study was conducted to evaluate the effect of phorbol 12,13-dibutyrate (PDBu) on the contraction of rabbit jugular vein in vitro. PDBu concentrations of greater than 10 nM induced a periodic contraction which was composed of rapid contraction, plateau and slow relaxation. The frequency of periodic contraction increased as PDBu concentration increased. The PDBu-induced contraction was inhibited by staurosporine (100 nM), it was not changed by tetrodotoxin $(1\;{\mu}M).$ In $Ca^{2+}$-free medium, PDBu induced a sustaining contraction, but not periodic contraction. Addition of $Ca^{2+}$ to medium evoked periodic contraction which was inhibited by nifedipine, PDBu concentrations of greater than $0.1\;{\mu}M$ increased ^{45}Ca^{2+}$ uptake without changing $^{45}Ca^{2+}$ efflux. Charybdotoxin and apamin, $Ca^{2+}$-activated K^{+}$ channel blockers, did not affect the PDBu-induced periodic contraction, whereas tetraethylammonium (TEA) abolished the periodicity. Pinacidil $(10\;{\mu}M).$, a potassium channel activator, blocked PDBu induced periodic contraction, which was recovered by glybenclamide $(10\;{\mu}M).$. In high potassium solution, PDBu did not produce the periodic contraction. These results suggest that the PDBu-induced periodicity of contraction is modulated by voltage dependent $Ca^{2+}$ channel and ATP-sensitive $K^{+}$ channel.

• Toxicological Research
• /
• 제18권3호
• /
• pp.227-232
• /
• 2002

In order to find out the appropriate in vitro method for high correlation with in vivo, we com-pared the sensitivities of phototoxicity (PT) in vitro method between in human keratinocytes, HaCaT cells and in 3T3 fibroblast cells derived from Balb/c mice. Both cells were exposed to six known phototoxic chemicals : promethazine, neutral red, chlortetracycline, amiodarone, bithionol, 8-methoxypsoralen, or non-phototoxic chemical, ALS (ammonium laureth sulfate) and then irradiated with 5 J/$cm^2$ of UVA. Cell viability ($IC_{50}$ ) was measured by neutral red uptake (NRU) assay. The ratio of $IC_{50}$ value of chemicals in the presence and absence of UVA was determined by the cut-off value. The phototoxic potential of test chemicals in NRU assay was determined by measuring the photoirriation factor (PIF) with a cut-off value of 5. In both 3T3 and HaCaT cells, all known phototoxic chemicals were positive (over 5 of PIF value), except that bithionol was found to be non-phototoxic to HaCaT cells, and ALS, non-phototoxic chemical was negative. These results suggest that Balb/c 3T3 cell was more sensitive than HaCaT cell to predict phototoxicity potential.