• Journal of Ecology and Environment
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• v.29 no.1
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• pp.23-27
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• 2006

This study was conducted to evaluate forest carbon cycling and soil $CO_2$ efflux rates in a 42-year-old pine (Pinus densiflora) stand located in Hamyang-gun, Korea. Aboveground and soil organic carbon storage, litterfall, litter decomposition, and soil $CO_2$ efflux rates were measured for one year. Estimated aboveground biomass carbon storage and increment in this stand were $3,250gC/m^2\;and\;156gC\;m^{-2}yr^{-1}$, respectively. Soil organic carbon storage at the depth of 30 cm was $10,260gC/m^2$ Mean organic carbon inputs by needle and total litterfall were $176gC\;m^{-2}yr^{-1}\;and\;235gC\;m^{-2}yr^{-1}$, respectively. Litter decomposition rates were faster in nne roots less than 2 mm diameter size ($<220\;g\;kg^{-1}yr^{-1}$) than in needle litter ($<120\;g\;kg^{-1}yr^{-1}$). Annual mean and total soil respiration rates were $0.37g\;CO_2m^{-2}h^{-1}$ and $2,732g\;CO_2m^{-2}yr^{-1}$ during the study period. A strong positive relationship existed between soil $CO_2$ efflux and soil temperature (r=0.8149), while soil $CO_2$ efflux responded negatively to soil pH (r=-0.3582).

• KSBB Journal
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• v.13 no.4
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• pp.383-390
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• 1998

Bacillus subtilis DT134 was resistant to 50-fold higher concentration of cadmium ions (Cd2+) than cadmium-sensitive B. subtilis BD224 in Luria Broth (LB) medium. Minimal inhibition concentration test in LB agar plates also showed similar results. The elevated cadmium resistance of B. subtilis DT134 strongly suggested a possible existence of cadmium resistance gene in it. Southern blot with Staphylococcus aureus cadA gene fragment (757 bp NlaIV-XmnI cadA DNA fragment) as probe was carried out to test the existence and similarity of the gene. In high stringency condition, there was no detectable signal, but in low stringency, a strong signal specific to the cadA probe could be detected. These results strongly suggested that there was some similarity between total DNA of B. subtilis DT134 and S. aureus pl258 in terms of cadmium resistance gene and the resistance mechanism might be an efflux mechanism. The subsequent efflux experiment showed that the cadmium resistance mechanism of B. subtilis DT134 was also due to the efflux of cadmium.

• Bulletin of the Korean Chemical Society
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• v.5 no.4
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• pp.154-158
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• 1984

In order to characterize the permeability of small unilamellar vesicles (SUV), efflux of 6-carboxyfluorescein (6-CF) from the vesicles was monitored spectrophotofluorometrically. Since the entrapped highly quenched 6-CF (200 mM) became fluorescent upon release from the vesicles, the 6-CF could be used as an efflux probe. SUV containing entrapped 6-CF was prepared from egg phosphatidylcholine and separated by gel filtration on Sepharose 4B. Observed change of relative fluorescent intensity with time was sigmoidal. From this curve, the parameter of permeability was determined either by half-time or a released amount per unit time from the initial slope. Half-time of efflux of prepared SUV having 302 ng phospholipid/ml in 10 mM Tris-HCl buffer pH 7.4 was 21.0 min at $37{\circ}C$. Various factors which could affect the half-time were examined including temperature, pH, salt, and vesicle concentration. In particular the effect of vesicle concentration on the efflux revealed that the permeability can be a function of the concentration.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.69.2-69.2
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• 2003

The purpose of this study is to examine whether the efflux system for taurine from brain to blood is present on the blood-brain barrier (BBB) using the brain efflux index (BEl) method and taurine transport system is regulated by CNS cell damage with oxidative stress agent such as diethyl maleate (DEM) or tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) in vivo. ［$^3$H]Taurine was microinjected into parietal cortex area 2 (Par2) of the rat brain, and was eliminated from the brain with efflux transport rate of 1.22 10$\^$-2//min, and the process is saturable with a $K_{m}$ of 43.5 ${\mu}$M. (omitted)

• Journal of Forest and Environmental Science
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• v.28 no.4
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• pp.232-241
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• 2012

We investigated the relationship between vegetation type and soil carbon dynamics in even-aged alder (Alnus hirsuta) and Korean pine (Pinus koraiensis) plantations in central Korea. Both forests were located on the same soil parent material and occupied similar topographic positions. Soil $CO_2$ efflux in the two plantations was determined using a dynamic chamber method accompanied by measurements of soil moisture content and temperature. Mean soil temperature was similar in the two plantations, but mean soil water content was significantly higher in the alder plantation than in the pine plantation. In both plantations, seasonal patterns in soil $CO_2$ efflux exhibited pronounced variation that corresponded to soil temperature. Soil water content did not affect the seasonal variation in soil $CO_2$ efflux. However, in summer, when soil temperature was above $17^{\circ}C$, soil $CO_2$ efflux increased linearly with soil water content in the alder plantation. Estimated $Q_{10}$ was 3.3 for the alder plantation and 2.7 for the pine plantation. Mean soil respiration during the measurement period in the alder plantation was 0.43 g $CO_2\;m^{-2}\;h^{-1}$, which was 1.3 times higher than in the pine plantation (0.33 g $CO_2\;m^{-2}\;h^{-1}$). Higher soil $CO_2$ efflux in the alder plantation might be related to nitrogen availability, particularly the concentration of $NO_3{^-}$, which was measured using the ion-exchange resin bag method.

• Nutrition Research and Practice
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• v.1 no.3
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• pp.200-205
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• 2007

The effects of taurine on plasma and liver cholesterol, erythrocyte ouabain sensitive Na efflux and platelet aggregation were examined in Sprague Dawley rats fed control or 0.5% cholesterol with 0.2% cholate diet. Plasma and liver levels of total cholesterol were increased significantly (p<0.05) in rats fed cholesterol diet compared to the control, and taurine significantly decreased the elevated plasma level of cholesterol in rats fed cholesterol diet (p<0.05). HDL-cholesterol was decreased in groups fed the cholesterol diet regardless of taurine supplementation and the difference between groups with and without cholesterol was significant (p<0.01). Plasma triglyceride was decreased and liver triglyceride was increased both significantly (p<0.05) in rats fed cholesterol compared to the control. Plasma and liver triglyceride in rats fed taurine was decreased significantly compared to the control (p<0.05). Intracellular Na tended to be lower in rats fed cholesterol or taurine and higher in rats fed cholesterol plus taurine compared to the control. Na efflux through Na-K ATPase and the passive leak of Na was somewhat reduced in rats fed cholesterol or taurine and was augmented in rats fed cholesterol plus taurine compared to the control, which showed a similar trend to the intracellular Na. Taurine supplementation caused a suppression of Na efflux in groups fed control diet and restored the suppressed Na efflux in groups fed cholesterol. Platelet aggregation was significantly decreased in the group fed taurine compared to the control (p<0.05) and the group fed cholesterol plus taurine was also a little lower in aggregation than the group fed cholesterol. Microscopic examination showed that taurine prevented fatty liver in rats fed cholesterol diet. Taurine known for stimulating Na-K ATPase in some cell types rather decreased erythrocyte ouabain sensitive Na-K ATPase in the present study. Taurine had hypolipidemic and hypocholesterolemic effects and inhibited platelet aggregation which may be favorable for prevention of cardiovascular diseases.

• Environmental Analysis Health and Toxicology
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• v.22 no.3
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• pp.227-233
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• 2007

It has been reported that hepatic glutathione (GSH) levels are decreased in diabetic patients, and glucagon increases hepatic efflux of GSH into blood. The signaling pathways responsible for mediating the glucagon effects on GSH efflux, however, are unknown. The signaling pathways involved in the regulation of GSH efflux in response to glucagon and insulin were examined in primary cultured rat hepatocytes. The GSH concentrations in the culture medium were markedly increased by the addition of glucagon, although cellular GSH levels are significantly decreased by glucagon. Insulin was also increased the GSH concentrations in the culture medium, but which is reflected in elevations of both cellular GSH and protein. Treatment of cells with 8-bromo-cAMP or dibutyryl-cAMP also resulted in elevation of the GSH concentrations in the culture medium. Pretreatment with H89, a selective inhibitor of protein kinase A, before glucagon addition markedly attenuated the glucagon effect. These results suggest that glucagon changes GSH homeostasis via elevation of GSH efflux, which may be responsible for decrease in hepatic GSH levels observed in diabetic condition. Furthermore, the present study implicates cAMP and protein kinase A in mediating the effect of glucagon on GSH efflux in primary cultured rat hepatocytes.

• Korean Journal of Environment and Ecology
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• v.28 no.6
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• pp.762-768
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• 2014

The purpose of this study is to analyze the soil $CO_2$ efflux and micro-climate of a preserved forest area located in a Mt. bulam urban nature park Quercus acutissima stand from June 2013 to May 2014. The research showed that the soil and heterotrophic $CO_2$ efflux were $28.14{\pm}7.99$ to $582.47{\pm}318.51$ and $12.32{\pm}8.04$ to $415.71{\pm}159.92mg\;CO_2{\cdot}m^{-2}{\cdot}h^{-1}$, respectively. In addition the seasonal soil $CO_2$ efflux of summer, autumn, winter, spring were 1169.1, 454.81, 72.08 and $494.23g\;CO_2{\cdot}m^{-2}{\cdot}month^{-1}$, respectively. On the other hand, the seasonal heterotrophic $CO_2$ efflux were 526.20, 340.09, 45.13 and $374.9g\;CO_2{\cdot}m^{-2}{\cdot}month^{-1}$, respectively. Moreover, the annual soil and heterotrophic $CO_2$ efflux was found to be 2190.22 and $1286.33g\;CO_2{\cdot}m^{-2}{\cdot}yr^{-1}$, respectively. The exponential function was also utilized for the regression analysis in order to correlate the environmental factors with the soil and heterotrophic $CO_2$ efflux. It was found out that both air and soil temperatures were positively correlated with the soil and heterotrophic $CO_2$ efflux. However, the amount of solar radiation and soil moisture has showed low correlation for both types of $CO_2$ efflux. Contribution of root $CO_2$ efflux to total soil $CO_2$ efflux in this Quercus acutissima stand was 33.60%.

• Korean Journal of Environment and Ecology
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• v.26 no.5
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• pp.780-786
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• 2012

A trenching method was used to determine the contribution of root respiration to soil respiration in Quercus acutissima forest in the vicinity of Gongju, Chungnam Province, Korea. $CO_2$ efflux in soil respiration plot($R_{control}$, $R_c$) and microblal respiration plot($R_{trenched}$, $R_t$) in Q. acutissima forest were measured from June 2011 to May 2012 by using IRGA soil respiration analyzer. Seasonal $CO_2$ efflux in $R_c$ and $R_t$ were higher in summer season than in winter season. In August, maximun $CO_2$ efflux in $R_c$ and $R_t$ was 1.345 and 0.897 g $CO_2\;m^{-2}\;hr^{-1}$, respectively. $CO_2$ efflux in $R_t$ was lower by 33.31% than that in $R_c$(P<0.05). In January, $CO_2$ efflux in $R_c$ and $R_t$ was 0.097 and 0.032g $CO_2\;m^{-2}\;hr^{-1}$, respectively. $CO_2$ efflux in $R_t$ was lower by 67.01% than that in $R_c$(P<0.01). The amount of annual $CO_2$ efflux from $R_c$ and $R_t$ was 4.320, 2.834kg $CO_2\;m^{-2}\;yr^{-1}$, respectively. There was a significant correlations between soil temperatures and soil respiration. Contribution of root respiration to total soil respiration in this Q. acutissima forest was 34.40%.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.3
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• pp.186-190
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• 2013

Soil respiration in forest ecosystems play an important role in global carbon cycle. This study was carried out to determine the annual variation of soil $CO_2$ efflux for 4 years in a broadleaved deciduous forest of the Geumsan (Mt.) Long-Term Ecological Research (GLTER) site in Southern Korea. The soil $CO_2$ efflux in the GLTER site showed annual variations with the fluctuations of annual mean soil temperature, but not with those of soil water content. The annual mean soil $CO_2$ efflux except for winter season was 0.32 g $CO_2\;m^{-2}h^{-1}$ for 2008, 0.40 g $CO_2\;m^{-2}h^{-1}$ for 2009, 0.41 g $CO_2\;m^{-2}h^{-1}$ for 2007, and 0.54 g $CO_2\;m^{-2}h^{-1}$ for 2010. The lowest soil $CO_2$ effluxin 2008 was associated with the lowest soil temperature ($2.0^{\circ}C$) in comparison with those of other years ($13.0-13.5^{\circ}C$). The exponential relationships between monthly soil $CO_2$ efflux and the corresponding soil temperature at the soil depth of 20 cm were significant ($R^2$ = 0.31-0.75, P < 0.05). The results indicate that the annual variation of soil $CO_2$ efflux was attributed to the variations of soil temperature rather than soil water content in the GLTER site.