Efflux Values Research Articles

The pH-dependence of efflux ratios determined with bidirectional transport assays across cellular monolayers

MDCK/Caco-2 assays serve as essential in vitro tools for evaluating membrane permeability and active transport, especially mediated by P-glycoprotein (P-gp). Despite their utility, challenges remain in quantifying active transport and using the efflux ratio (ER) to determine intrinsic values for active efflux. Such an intrinsic value for P-gp facilitated efflux necessitates knowing whether this transporter transports the neutral or ionic species of a compound. Utilising MDCK-MDR1 assays, we investigate a method for determining transporter substrate fraction preference by studying ER pH-dependence for basic, acidic and non-dissociating compounds. These results are compared with model fits based on various assumptions of transporter species preference. As an unexpected consequence of these assays, we also give evidence for an additional influx transporter at the basolateral membrane, and further extend our model to incorporate this transport. The combined influences of paracellular transport, the previously unaccounted for basolateral influx transporter, as well as potential pH effects on the transporter impedes the extraction of intrinsic values for active transport from the ER. Furthermore, we determined that using inhibitor affects the measurement of paracellular transport. While clear indications of transporter species preference remain elusive, this study enhances understanding of the MDCK system.

Dense Contaminants Mixing Into the Saltwater Wedge in Coastal Aquifers: Laboratory and Numerical Investigations

AbstractThe saltwater‐freshwater mixing zones in coastal aquifers can host complex physical exchange and biogeochemical transformations. The land‐sourced dense contaminant plumes could be transferred into the mixing zone of the saltwater wedge due to the density effect prior to discharge to the sea. However, the mixing process between dense contaminants and the saltwater wedge has not received much attention, largely due to the lack of physical evidence. This study used laboratory experiments and numerical simulations to investigate the transport and discharge behaviors of variable‐density contaminant plumes in tidally influenced unconfined coastal aquifers. Results demonstrate that the highly dense contaminants mix with the underlying saltwater and finally merge with the saltwater wedge. This process significantly extends the contaminant discharge durations, thereby reducing the peak value of contaminant efflux. The dense contaminants are elongated along the landward margin of the saltwater wedge, leading to a larger spreading area (Ms) than that of constant‐density contaminants. The sensitivity analysis indicates that the high density of contaminants acts as a trigger to induce the mixing of them and wedges. The higher hydraulic conductivity, lower dispersivities and reduced inland freshwater flux significantly increase the residence times (Rt) and discharge duration (Dt) by enhancing the mixing of dense contaminants with seawater. In contrast, both Rt and Dt values are not only non‐monotonic functions of tidal amplitudes but also less sensitive to tidal effects. Compared with the non‐tidal condition, however, the addition of tides significantly increases both Rt and Ms values of dense contaminant plumes. The results presented herein provide valuable insights into the mechanisms of dense contaminants mixing into saltwater wedges, which could guide practitioners in designing effective strategies to protect coastal environments from land‐sourced contaminants.

CO2 and heat energy transport by enhanced fracture permeability in the Monterotondo Marittimo-Sasso Pisano transfer fault system (Larderello Geothermal Field, Italy)

Carbon dioxide is one of the most important gasses naturally released from geothermal systems. Establishing the processes and pathways that regulate the CO2 diffuse degassing can provide valuable information for exploration and exploitation purposes of geothermal reservoirs. In this work, a high-resolution CO2 flux (with records up to 2927 g m–2 d–1) and soil temperature (with records up to 98.8 °C) survey was carried out along with detailed fracture parameters measurements in a selected area of the Monterotondo Marittimo-Sasso Pisano transfer fault (Larderello geothermal system, Tuscany, Italy). The main aim was to define the behavior of diffuse CO2 through the fault system and investigate how the soil CO2 flux and steam change with respect to the architecture of the fault damage zone (i.e., volumetric fracture intensity, permeability, and persistence of the fractures). The presence of multiple populations of CO2 flux suggested that three different transport mechanisms control soil degassing: i) purely diffusive, ii) mixed diffusive-advective, and iii) purely advective, characterized by efflux values of <20, between 20 and 300 and >300 g m–2 d–1, respectively. The spatial distribution of these fluxes well agrees with the fracture distribution and features of the Jurassic radiolarite (Diaspri Fm) dissected by NNE-striking faults. Areas with high CO2 emissions are indeed able to reveal major upflow areas from deep reservoirs through deep-reaching permeable fault zones. The interaction between pre-existing fractures and fracture-related fault-zone locally enhances the secondary rock permeability as highlighted by the correlation between Discrete Fracture Network (DFN) modeling and advective flux. Eventually, by normalizing the CO2 output to the fault strip (1350 m2), a release of CO2 equal to ∼155 t d–1 km–2 was estimated.

Treatment of Cardiovascular Dysfunction with PDE3-Inhibitors in Moderate and Severe Hypothermia-Effects on Cellular Elimination of Cyclic Adenosine Monophosphate and Cyclic Guanosine Monophosphate.

Introduction: Rewarming from accidental hypothermia is often complicated by hypothermia-induced cardiovascular dysfunction, which could lead to shock. Current guidelines do not recommend any pharmacological treatment at core temperatures below 30°C, due to lack of knowledge. However, previous in vivo studies have shown promising results when using phosphodiesterase 3 (PDE3) inhibitors, which possess the combined effects of supporting cardiac function and alleviating the peripheral vascular resistance through changes in cyclic nucleotide levels. This study therefore aims to investigate whether PDE3 inhibitors milrinone, amrinone, and levosimendan are able to modulate cyclic nucleotide regulation in hypothermic settings. Materials and methods: The effect of PDE3 inhibitors were studied by using recombinant phosphodiesterase enzymes and inverted erythrocyte membranes at six different temperatures—37°C, 34°C, 32°C, 28°C, 24°C, and 20°C- in order to evaluate the degree of enzymatic degradation, as well as measuring cellular efflux of both cAMP and cGMP. The resulting dose-response curves at every temperature were used to calculate IC50 and Ki values. Results: Milrinone IC50 and Ki values for cGMP efflux were significantly lower at 24°C (IC50: 8.62 ± 2.69 µM) and 20°C (IC50: 7.35 ± 3.51 µM), compared to 37°C (IC50: 22.84 ± 1.52 µM). There were no significant changes in IC50 and Ki values for enzymatic breakdown of cAMP and cGMP. Conclusion: Milrinone, amrinone and levosimendan, were all able to suppress enzymatic degradation and inhibit extrusion of cGMP and cAMP below 30°C. Our results show that these drugs have preserved effect on their target molecules during hypothermia, indicating that they could provide an important treatment option for hypothermia-induced cardiac dysfunction.

Hydrochemical and Hydroacoustic Investigation of the Yugama Acid Crater Lake, Kusatsu-Shirane, Japan

The gases dissolved in the waters of volcanic lakes can present a serious hazard if the physical-chemical conditions change due to variations in the supply of magmatic gases. The monitoring of gases such as CO2 and He help us understand the degassing process and their connection with magmatic/hydrothermal system. One of the most acidic volcanic lakes on the planet is the Yugama, on Kusatsu Shirane volcano (Japan). We report the results of an interdisciplinary study carried out in August 2013 at Yugama consisting of the first estimation of rate of diffuse CO2 emission, the chemical and isotopic analysis of water and dissolved gases in samples from vertical lake profiles, and an echo-sounding survey. The lake water has an average temperature of 24-25°C, pH 1.01, concentrations of SO42- between 1,227 and 1,654 mgL−1 and Cl− between 1,506 and 2,562 mgL−1, with gas bubbling at several locations and floating sulfur globules with sulfide inclusions. A total of 66 CO2 efflux measurements were taken at the lake surface by means of the floating accumulation chamber method to estimate the diffuse CO2 output from the studied area. CO2 efflux values ranged from 82 up to 25,800 g m−2 d−1. Estimation of the diffuse CO2 emission at Yaguma Crater Lake was 30 ± 12 t d−1. Normalized CO2 emission rate (assuming an area of 0.066 km2) was 454 t km−2 d−1, a value within the range of acid volcanic lakes. Vertical profiles of major ions and dissolved gases showed variations with increases in ion content and dissolved CO2 and He with depth. Acoustic imaging shows the presence of intense bubbling and provides important information on the bathymetry of the lake. The 50–200 kHz echograms exhibit frequent vertical plumes of rising gas bubbles. Within the crater-lake, three circular submarine vents have been identified showing flares due to a significant activity of sublacustrine emissions. This work shows the first data of diffuse CO2 degassing, dissolved gases in water and echosounding (ES) from Yugama Crater Lake. Periodic hydrogeochemical and hydroacoustic surveys at Yugama Crater Lakemay thus help to document changes in the state of activity of this high-risk volcanic area.

Effects of aromatic crops based cropping systems and residue returning on soil CO2 emission compared to fallow soil

Two years field experiment was done to investigate the impact of aromatic crops based cropping systems and crop residue returning on soil CO2 efflux and its relationship with soil temperature and moisture. Eight diversified cropping systems were compared to fallow soil as control, total nine treatments: T1-(B-W-C) (basil-wheat-cowpea), T2-(B-W-M) (basil-wheat-menthol mint), T3-(B-P-C) (basil-potato-cowpea), T4-(B-P-M) (basil-potato-menthol mint), T5-(B-L-C) (basil-lentil-cowpea), T6 -(B-L-M) (basil-lentil-menthol mint), T7-(B-Pe-C) (basil-pea-cowpea), T8-(B-Pe-M) (basil-pea-menthol mint) and T9-(F-F-F) (fallow soil). Surface soil CO2 efflux, temperature and moisture of each crop were measured in each season at 15 days interval. Cumulative soil CO2-C emission was calculated on basis of soil CO2 efflux values obtained. T9-(F-F-F) emitted maximum CO2-C in both cropping years, 21.57 Mg C ha−1 and 24.28 Mg C ha−1 in first and second year, respectively. Within cropping systems, maximum was emitted by T1-(B-W-C) and T7-(B-Pe-C). T1 (13.64 Mg C ha−1) and T7 (13.48 Mg C ha−1) in first cropping year while in second cropping year both these cropping systems (T1 and T7) emitted 15.82 Mg C ha−1. Minimum soil CO2-C in both the cropping years was emitted from cropping system T4-(B-P-M) (10.66 Mg C ha−1 and 12.74 Mg C ha−1). Crop residue of the previous crop returned back to soil had significant effect on soil CO2 efflux. Soil CO2-C emission of all treatments (T1-T9) was found to increase with subsequent cropping year. Simple linear regression analysis was performed to elucidate the correlation between soil CO2 efflux, temperature and moisture in all the seasons (rainy, winter and summer). In each season, the soil CO2 efflux was positively correlated to soil temperature and negatively correlated with soil moisture in both the cropping years. Aromatic crops based diversified cropping systems along with residue retention did not decrease the soil CO2-C emission but showed less emission compared to fallow soil.

Wildfire and harvesting effects on carbon dynamics in an oak-pine mixed forest

CO2 emission to the atmosphere is the main cause of global warming. The impacts of land-use changes for agriculture and urbanisation, deforestation, and fire disturbance are attributed to the increase in CO2 emissions. Soil respiration, largely due to microbial activity, is one of the CO2 sources being released to the atmosphere. In this regard, several soil parameters related with carbon cycle, including organic matter, total N, C/N ratio, CO2 efflux, microbial biomass C (Cmic), the Cmic/Corg ratio, the metabolic quotient qCO2, and β-D glucosidase activity, were determined in a burned (harvested, H; non-harvested, NH), and its adjacent unburned (UB), mixed oak-pine forest to estimate the effects of burning and removal of residual woods. The Cmic increased gradually with burning and harvesting after Month 9, and sharp increases were observed in all areas, likely due to the abundant rainfall after Month 12. CO2 efflux decreased in the burned areas at Months 4 and 6; however, this reversed in Month 9. In spite of non-significant differences, we detected higher CO2 efflux values in the unburned areas compared to the burned ones, probably as a result of the drought effect observed in the burned areas up to Months 9 and 12 due to the increased soil heat. There was no significant difference between the H and NH burned areas, while both areas were different from the unburned areas in all soil parameters, except CO2 efflux and qCO2. The harvesting effect was not significant compared to the fire effect with regard to the considered soil variables, likely due to the management and protection of the burned area which allowed a fast vegetation recover. The abundance of the microbial biomass was independent of the changes in CO2 efflux and showed a negative correlation with β-D glucosidase activity. This might be related to the variation in substrate quality, microbial composition and abundance after burning and harvesting.

Estimation of salt balance in salt-affected ecosystems in arid areas, Case Study: El Fayoum depression, Egypt. (Dept. C. ( Irrigation And Hydraulics ) )

El Fayoum depression is a semi-closed depression located about 100 Km southwest of Cairo-Egypt It occupies an area of about 1200 Km2. Due to the complex geological and hydrological conditions of that area, water logging problem and soil salinization affect great parts of the cultivated areas. The geological conditions are manifested in the rich content of clay in the Quaternary aquifer, the relative small aquifer thickness and the dominance of faulted and fractured limestone at the base and on the peripheries. On the other hand, the hydrological conditions include the occurrence of a thick net of irrigation system and presence of huge surface water bodies; e.g. Qarun lake and Wadi El Rayan lakes. Moreover, the groundwater depths vary from few centimeters below ground surface to 7.51 m which reflect a critical soil salt-affected problem. The present paper throws light on the salt balance of the groundwater regime. The estimation of the input and output components is carried out based on the field measurements during 2006. The estimated mean annual salt influx reaches 2.05 million tons. The Output component includes the salt efflux through the drainage network, subsurface groundwater flow and the salinity losses due to plant uptake. The estimated annual mean value of salt efflux from these three components reaches 3.8 million tons. The average annual storage component is estimated to be -1.75 million tons. The estimation of salt balance shows that the groundwater or/and soil water receive an excess of annual salt content of 1.75 million tons due to leaching process of evaporites and clay lenses during its flow from the upstream till it reaches the downstream area (Qarun Lake). Mitigation of imbalanced salt load through minimizing the losses from drainage network and using low consumed cop pattern is highly recommended.

Magmatic volatiles to assess permeable volcano-tectonic structures in the Los Humeros geothermal field, Mexico

Magmatic volatiles can be considered as the surface fingerprint of active volcanic systems, both during periods of quiescent and eruptive volcanic activity. The spatial variability of gas emissions at Earth's surface is a proxy for structural discontinuities in the subsurface of volcanic systems. We conducted extensive and regular spaced soil gas surveys within the Los Humeros geothermal field to improve the understanding of the structural control on fluid flow. Surveys at different scales were performed with the aim to i) identify areas of increased gas emissions (reservoir scale), ii) their relation to (un)known volcano-tectonic structures (fault scale) favoring fluid flow, and iii) determine the origin of gas emissions. Herein, we show results from a CO2 efflux scouting survey, which was performed across the main geothermal production zone (6 km × 4 km) together with soil temperature measurements. We identified five areas with increased CO2 emissions, where further sampling was performed with denser sampling grids to understand the fault zone architecture and local variations in gas emissions. CO2 efflux values range from below detection limit of the device to 1464 g m−2 d−1 with a total output of 87 t d−1 across an area of 13.7 km2. Furthermore, δ13CCO2 and 3He/4He analyses complemented the dataset in order to assess the origin of soil gases. Carbon isotopic data cover a broad spectrum from biogenous to endogenous sources. Determined 3He/4He ratios indicate a mantle component in the samples of up to 65% being most evident in the northwestern and southwestern part of the study area. We show that a systematic sampling approach on reservoir scale is necessary for the identification and assessment of major permeable fault segments. The combined processing of CO2 efflux and δ13CCO2 facilitated the detection of permeable structural segments with a connection to the deep, high-temperature geothermal reservoir, also in areas with low to intermediate CO2 emissions. The results of this study complement existing geophysical datasets and define further promising areas for future exploration activities in the north- and southwestern sector of the production field.

In mitigating CO2 emission in the reservoir riparian: The influences of land use and the dam-triggered flooding on soil respiration

Soil respiration (SR) has been found to be highly influenced by land use and soil water regimes. However, the relative contribution of farming and dam-triggered flooding in influencing the SR of the riparian zone is poorly understood. The objectives of this study were to investigate the effects of land use and dam-triggered flooding intensity on SR in the riparian zone along the Three Gorges Reservoir (TGR), China, and to identify the main factors shaping the SR. At the Wuyang Bay of the Pengxi River, a tributary of the Yangtze River in the TGR, a series of SR field examinations in different land-use types and along elevation gradients in the riparian zone were carried out from March to September in 2018. During the study period, by analyzing SR in 177 m (elevation above sea level, the same as follows) unflooded site (UF), 173 m corn field (173C), 173 m paddy field (173 P), 168 m corn field (168C), 168 m paddy field (168 P), 168 m fallow grassland (168 F), 166 m fallow grassland (166 F), 163 m corn field (163C) and 163 m fallow grassland (163 F), significant differences in diurnal variations were found to be mainly affected by soil temperature (ST) at 10 cm depth, while seasonal variations were mainly regulated by ST and rainfall events (i.e. 10 cm depth soil water content). Importantly, croplands were found to contain higher soil organic carbon (SOC) but lower SR efflux and Q10 values than those for non-cropping fields. The results imply that SR was strongly affected by land-use types rather than flooding intensity in the TGR riparian zone. Furthermore, this study highlights the significant impacts of tillage in stabilizing SOC and reducing SR efflux in the area that is highly influenced by hydrological regime shift. Finally, from the perspective of controlling the soil carbon dioxide emission, we suggest that local government should manage and guide farming activities in the riparian zone.

Role of HDL function and LDL atherogenicity on cardiovascular risk: A comprehensive examination.

BackgroundHigh-density lipoprotein (HDL) functionality and low-density lipoprotein (LDL) atherogenic traits can describe the role of both particles on cardiovascular diseases more accurately than HDL- or LDL-cholesterol levels. However, it is unclear how these lipoprotein properties are particularly affected by different cardiovascular risk factors.ObjectiveTo determine which lipoprotein properties are associated with greater cardiovascular risk scores and each cardiovascular risk factor.MethodsIn two cross-sectional baseline samples of PREDIMED trial volunteers, we assessed the associations of HDL functionality (N = 296) and LDL atherogenicity traits (N = 210) with: 1) the 10-year predicted coronary risk (according to the Framingham-REGICOR score), and 2) classical cardiovascular risk factors.ResultsGreater cardiovascular risk scores were associated with low cholesterol efflux values; oxidized, triglyceride-rich, small HDL particles; and small LDLs with low resistance against oxidation (P-trend<0.05, all). After adjusting for the rest of risk factors; 1) type-2 diabetic individuals presented smaller and more oxidized LDLs (P<0.026, all); 2) dyslipidemic participants had smaller HDLs with an impaired capacity to metabolize cholesterol (P<0.035, all); 3) high body mass index values were associated to lower HDL and LDL size and a lower HDL capacity to esterify cholesterol (P<0.037, all); 4) men presented a greater HDL oxidation and lower HDL vasodilatory capacity (P<0.046, all); and 5) greater ages were related to small, oxidized, cytotoxic LDL particles (P<0.037, all).ConclusionsDysfunctional HDL and atherogenic LDL particles are present in high cardiovascular risk patients. Dyslipidemia and male sex are predominantly linked to HDL dysfunctionality, whilst diabetes and advanced age are associated with LDL atherogenicity.

НОВЫЙ АКУСТИЧЕСКИЙ МЕТОД КОЛИЧЕСТВЕННОЙ ОЦЕНКИ ПУЗЫРЬКОВОГО ПОТОКА МЕТАНА В СИСТЕМЕ ДОННЫЕ ОТЛОЖЕНИЯ – ВОДНАЯ ТОЛЩА И ЕГО РЕАЛИЗАЦИЯ НА ПРИМЕРЕ МОРЯ ЛАПТЕВЫХ, СЕВЕРНЫЙ ЛЕДОВИТЫЙ ОКЕАН

Актуальность исследования обусловлена необходимостью разработки научно-обоснованного подхода к количественной оценке пузырькового переноса метана (СН4) и других газов на основе акустических методов, позволяющих проводить достоверную оценку потока метана из областей его пузырьковой разгрузки с помощью эхолотов и гидролокаторов. Цель исследования: разработка репрезентативного акустического метода количественной оценки потока метана из областей пузырьковой разгрузки в системе донные осадки – водная толща, основанного на определении количества всплывающих пузырьков, по данным о сечении их обратного рассеяния; обоснование репрезентативности разработанного метода путем сравнения с методом, основанным на проведении специальной калибровки научного эхолота по искусственному газовому факелу. Объекты: газовые факелы – эманации газа в виде всплывающих со дна пузырьков, которые образуют в водной толще устойчивые области их повышенной концентрации. Методы: разработанные авторским коллективом методы оценки потока СН4 из областей пузырьковой разгрузки, основанные на измерении: 1) сечения рассеяния всплывающих пузырьков; 2) калибровки по искусственному газовому факелу. Результаты. Представлен обзор современных акустических дистанционных методов, применяемых для оценки потоков СН4 в водной толще, связанных с выходящими из дна и всплывающими пузырьками. На примере обширной области пузырьковой разгрузки СН4 на шельфе моря Лаптевых обоснована репрезентативность предложенного нового метода, основанного на расчете по сечению обратного рассеяния всплывающих пузырьков СН4. Показано, что оценки величины пузырькового потока, полученные двумя методами: 1) новым методом, разработанным авторами, и 2) методом калибровки эхолота по искусственному газовому факелу, дают схожие результаты: 0,27±0,06 и 0,33±0,07 ммоль•м–2•с–1, соответственно. Таким образом, на практике для дистанционной и оперативной оценки потоков СН4 с участков его пузырьковой разгрузки можно использовать оба метода, с учетом занижения расчета потока по сечению обратного рассеяния примерно на 20 % относительно реальных значений.

Diurnal and seasonal patterns of soil CO2 efflux from the Pichavaram mangroves, India.

The diurnal and seasonal variation of soil carbon dioxide (CO2) flux was measured in the Pichavaram mangrove forest, the Southeast coast of India from February 2016 to October 2016 using an automated soil CO2 flux chamber system. Maximum soil CO2 efflux reached at 14:00h and minimum at 00:00h. The surface soil CO2 concentration ranged from 375 to 532ppm with the mean 405 ± 18ppm. The daily soil CO2 flux varied from near zero to about 7μmolm-2s-1 with a mean value of 2.4 ± 1.3μmolm-2s-1. The highest seasonal CO2 efflux from soil was during the summer and premonsoon seasons, whereas low flux values were recorded during the monsoon season. Soil CO2 efflux values were highly correlated with soil temperature. Tidal inundation during monsoon season, extreme drought condition in summer, and unusual precipitation are the major factors controlling the soil CO2 flux.

Wetland Soil Co2 Efflux Along a Latitudinal Gradient of Spatial and Temporal Complexity

Foundation plant species play an important functional role in modifying microenvironment through vegetation structure and by influencing soil properties. Mangroves and salt marsh differ in vegetation structure, yet offer similar ecosystem services. This work aimed to understand how different vegetation classes and abiotic factors along a latitudinal gradient of spatial and temporal complexity affect soil CO2 efflux. Soil CO2 efflux, biomass, soil properties, and soil and air temperature were measured in July 2015 and January 2016 in situ at 10 sites along a 342-km latitudinal gradient on the Atlantic coast of Florida. Mean CO2 flux values ranged from 0.41 ± 0.19 to 2.03 ± 0.19 μmol m−2 s−1 across vegetation classes, and efflux values in mangrove plots were not significantly different between sampling dates, whereas ecotone and salt marsh efflux values were. On average, CO2 flux was 1.11 ± 0.18 μmol m−2 s−1 greater in July than in January across plots. There was no significant trend between efflux and aboveground biomass and a positive trend between belowground biomass and CO2 efflux. Edaphic parameters (organic matter content (%), soil N, organic C, and pH) were comparable across all vegetation class soils and there was a positive trend between soil temperature and flux. Soil efflux had an inverse relationship with latitude; in January, there is an increase in efflux with a decrease in latitude, while in July, efflux increases with an increase in latitude. Consequently, we assert that differences in CO2 efflux were due to soil temperature and species productivity along the latitudinal gradient studied.

Evaluating organic carbon fractions, temperature sensitivity and artificial neural network modeling of CO2 efflux in soils: Impact of land use change in subtropical India (Meghalaya)

The present study investigates the changes in land use pattern from fallow land (control) to fruit orchards on soil organic carbon (SOC) dynamics especially, organic carbon stocks, fractions, and CO2 efflux. The SOC fractions such as total organic carbon (TOC), particulate organic carbon (POC), readily oxidizable carbon (ROC), non-labile carbon (CNL), microbial biomass carbon (MBC), carbon management index (CMI) and their sensitivity to land use change were the focus of this study. The organic carbon fractions showed increasing trend (19.4–46%) under fruit orchards compared to control. Furthermore, the orchard with P. persica recorded the highest mean SOC stocks (59.4 Mg ha−1) and TOC (3.03 g 100 g−1) while orchard with C. reticulata showed the highest ROC (6.11 g kg−1) and MBC (401 mg kg−1). Fruit orchards were characterized by high Cmic:CTOC (microbial quotient; qMIC) and POC: TOC ratios, indicating an increase in substrate availability. Furthermore, the CMI was highest under C. reticulata (226.4) followed by P. guajava (173.3), whereas P. communis showed relatively lower value (160.5). While, upper soil layer (0–15 cm) exhibited higher organic carbon stock and fractions viz., 35.1 % and 58.3%, respectively compared to the subsurface soil (15–75 cm) in all orchards. The labile SOC fractions (POC, ROC, and MBC) showed a positively significant correlation with TOC and CO2 efflux indicating that these labile fractions are the sensitive indicators of soil quality changes and improvements. Soil CO2 efflux exhibited a pronounced variation corresponding to land use change with values ranging from 22.80 µg C g−1 h−1 (fallow land) to 27.39 µg C g−1 h−1 (P. guajava). With temperature increment from 25 to 35 °C, the soil CO2 efflux increased from 55% (P. persica) to 88% (fallow) with an average increase of 72%. However, the microbial metabolic quotient (qCO2), also called as specific respiratory activity (SRA), was relatively lower (40.9 µg CO2 mg MBC−1) in orchards compared to fallow land (50.4 µg CO2 mg MBC−1). A multi-layered Artificial Neural Network model (ANN) was also developed, and the experimental CO2 efflux values obtained from different land uses are in good agreement with the predicted CO2 efflux. We conclude that, labile SOC fractions are highly sensitive to land use change and could be effectively used as the sensitive indicators along with CMI for land use change under mid-altitude subtropical ecosystems. In addition, fruit orchards could store more carbon thus could be a potential option to mitigate global warming.

Effects of indomethacin on erythrocyte nitric oxide metabolism and erythrocyte deformability

Increased erythrocyte filtration index (decreased erythrocyte deformability; ED) was observed in patients with Behcet disease. When patients with Behcet took indomethacin, decreased values of erythrocyte acetylcholinesterase enzyme activity were obtained. An inverse association between nitric oxide (NO) efflux from erythrocytes and ED values was verified in blood samples of patients with vascular inflammatory diseases. The aim of this in vitro study was to verify the effect of indomethacin on ED, NO efflux, nitrite nitrate, peroxynitrite and nitroso- glutathione (GSNO) in the presence of protein tyrosine kinase (PTK Syk), protein tyrosine phosphatase (PTP), adenylyl cyclase (AC) and phosphatidylinositol 3 kinase (PI3K) enzyme inhibitors respectively Syk inhibitor, calpeptin, MDL and wortmannin (WORT). Blood samples from ten healthy donors were divided and aliquots were performed in absence (control aliquot) and presence of indomethacin or indomethacin plus each one of the inhibitors. Further ED and NO efflux and its metabolites were evaluated by the usual methodology. A significant increase in ED values was noted in the presence of indomethacin plus WORT. No significant differences where verified in NO efflux from erythrocytes in all blood aliquots. Significantly increase in GSNO concentration in the presence of indomethacin plus calpeptin, MDL or Wort were observed. Nitrate and peroxynitrite concentrations increased or decreased significantly respectively in all aliquots in relation to the control one. The nitrite levels increased in the aliquots with indomethacin and indomethacin plus MDL, or indomethacin plus Syk. In conclusion indomethacin act as antioxidant decreasing peroxynitrite, not changing NO efflux values and increasing nitrate levels independent of band 3 phosphorylation degree or cyclic adenosine monophosphate (cAMP) concentration. Indomethacin mobilizes nitrite and GSNO in dependant of band 3 phosphorylation degree and cAMP. Indomethacin did not change erythrocyte deformability, unless in combination with wortmannin which increased it.

Seasonal and Daily Dynamics of the CO2 Emission from Soils of Pinus koraiensis Forests in the South of the Sikhote-Alin Range

The presented study shows the results of measuring soil respiration in typical burozems (Dystric Cambisols) under mixed Korean pine–broadleaved forests in the southern part of the Primorskii (Far East) region of Russia growing under conditions of monsoon climate. The measurements were performed in 2014–2016 by the chamber method with the use of a portable infrared gas analyzer. Relative and total values of the CO2 efflux from the soil surface on four model plots were determined. The intensity of summer emission varied from 2.25 to 10.97 μmol/(m2 s), and the total CO2 efflux from the soils of four plots varied from 18.84 to 25.56 mol/m2. It is shown that a larger part of seasonal variability in the soil respiration is controlled by the soil temperature (R2 = 0.5–0.7); the soil water content also has a significant influence on the CO2 emission determining about 10% of its temporal variability. The daily dynamics of soil respiration under the old-age (200 yrs) forest have a significant relationship with the soil temperature (R2 = 0.51). The pyrogenic transformation of Pinus koraiensis forests into low-value oak forests is accompanied by an increase in the СО2 efflux from the soil.

The role of OAT2 (SLC22A7) in the cyclic nucleotide biokinetics of human erythrocytes.

The present study was conducted to characterise the transporter(s) responsible for the uptake of cyclic nucleotides to human erythrocytes. Western blotting showed that hRBC expressed OAT2 (SLC22A7), but detection of OAT1 (SLC22A6), or OAT3 (SLC22A8) was not possible. Intact hRBC were employed to clarify the simultaneous cyclic nucleotide egression and uptake. Both these opposing processes were studied. The Km‐values for high affinity efflux was 3.5 ± 0.1 and 39.4 ± 5.7 μM for cGMP and cAMP, respectively. The respective values for low affinity efflux were 212 ± 11 and 339 ± 42 μM. The uptake was characterised with apparently low affinity and similar Km‐values for cGMP (2.2 mM) and cAMP (0.89 mM). Using an iterative approach in order to balance uptake with efflux, the predicted real Km‐values for uptake were 100–200 μM for cGMP and 50–150 μM for cAMP. The established OAT2‐substrate indomethacin showed a competitive interaction with cyclic nucleotide uptake. Creatinine, also an OAT2 substrate, showed saturable uptake with a Km of 854 ± 98 μM. Unexpectedly, co‐incubation with cyclic nucleotides showed an uncompetitive inhibition. The observed Km‐values were 399 ± 44 and 259 ± 30 μM for creatinine, in the presence of cGMP and cAMP, respectively. Finally, the OAT1‐substrate para‐aminohippurate (PAH) showed some uptake (Km‐value of 2.0 ± 0.4 mM) but did not interact with cyclic nucleotide or indomethacin transport.

Soil carbon dioxide emissions due to oxidative peat decomposition in an oil palm plantation on tropical peat

Soil carbon dioxide (CO2) efflux was measured continuously for two years using an automated chamber system in an oil palm plantation on tropical peat. This study investigated the factors controlling the CO2 efflux and quantified the annual cumulative CO2 emissions through soil respiration and heterotrophic respiration, which is equivalent to oxidative peat decomposition. Soil respiration was measured in close-to-tree (<2.5m, CT) and far-from-tree (>3m, FT) plots, and heterotrophic respiration was measured in root-cut (RC) plots by a trenching method. The daily mean CO2 efflux values (mean±1 standard deviation) were 2.80±2.18, 1.59±1.18, and 1.94±1.58μmolm−2s−1 in the CT, FT, and RC plots, respectively. Daily mean CO2 efflux increased exponentially as the groundwater level or water-filled pore space decreased, indicating that oxidative peat decomposition and gas diffusion in the soil increased due to enhanced aeration resulting from lower groundwater levels. Mean annual gap-filled CO2 emissions were 1.03±0.53, 0.59±0.26, and 0.69±0.21kgCm−2 yr−1 in the CT, FT, and RC plots, respectively. Soil CO2 emissions were significantly higher in the CT plots (P<0.05), but did not differ significantly between the FT and RC plots. This implies that root respiration was negligible in the FT plots. Heterotrophic respiration accounted for 66% of soil respiration. Annual CO2 emissions through both soil and heterotrophic respiration were smaller than those of other oil palm plantations on tropical peat, possibly due to the higher groundwater levels, land compaction, and continuous measurement of soil CO2 efflux in this study. Mean annual total subsidence was 1.55 to 1.62cmyr−1, of which oxidative peat decomposition accounted for 72 to 74%. In conclusion, water management to raise groundwater levels would mitigate soil CO2 emissions from oil palm plantations on tropical peatland.

Development of an assay for cellular efflux of pharmaceutically active agents and its relevance to understanding drug interactions.

Drug interactions may dictate the failure or success of a treatment. Patients undergoing hematopoietic stem cell transplantation (HSCT) are exposed to various types of drugs, and understanding how these drugs interact is of the utmost importance. The pharmacokinetics of busulfan, melphalan, and cyclophosphamide, drugs commonly used for HSCT, are known to be affected by a variety of other drugs with differing molecular structures. We hypothesized that these structurally unrelated drugs affect the transport of DNA-alkylating agents. To test this hypothesis, we developed a flow cytometry assay that used 5-carboxyfluorescein diacetate acetoxymethyl ester, which is cleaved by nonspecific intracellular esterases to 5-carboxyfluorescein (5-CF), a fluorescent ligand for the drug transporter MRP1. A decreased 5-CF efflux in the presence of a test compound suggests competitive inhibition. We demonstrated that chlorambucil, 4-hydroperoxycyclophosphamide, ketoconazole, ethacrynic acid, everolimus, and sirolimus strongly inhibited 5-CF efflux in lymphoma and leukemia cell lines. The efflux of these drugs partially depends on the glutathione (GSH) level, and their cytotoxicity is synergistic with inhibited GSH synthesis. This is consistent with the hypothesis that their GSH-conjugated products are ligands of a common cellular drug transporter. Our results may explain clinical observations on the effects of various drugs on the pharmacokinetics and pharmacodynamics of alkylating agents, and the assay may be used to deduce interaction mechanisms of drugs transported by a common system.