Carbon pools in forest systems and new estimation based on an investigation of carbon sequestration.

Forests, the ancient wooden giants, are both symbols of natural beauty and reservoirs of carbon stocks. The current climate crisis has created an urgent need for an in-depth study of forest ecosystems and carbon stocks. Based on forest inventory data from field surveys and four bioclimatic zones [Zone 1 (Z1, humid forest), Zone 2 (Z2, semi-humid forest), Zone 3 (Z3, semi-humid to semi-arid forest-grassland), and Zone 4 (Z4, semi-arid typical grassland)], two methods [Method 1 (M1) and Method 2 (M2)] were used to estimate carbon stocks in forest ecosystems in Shaanxi Province, China, and explored the spatial patterns of carbon pools and potential influences. The total forest ecosystem carbon pool amounted to 520.80 Tg C, of which 53.60% was stored aboveground, 17.16% belowground, and 29.24% in soil (depth of 0-10 cm). Spatially, there were marked north-south gradients in both biomass (Z2 > Z3 > Z1 > Z4) and soil organic carbon densities (Z1 > Z2 > Z3 > Z4). The differences between aboveground and belowground biomass carbon density across broadleaf, needle-leaf, and broadleaf and needle-leaf mixed forest were not pronounced, while soil organic carbon density had the order of broadleaf (18.38 Mg C/ha) > needle-leaf (11.29 Mg C/ha) > broadleaf and needle-leaf mixed forest (10.33 Mg C/ha). Under an ideal scenario that excludes external factors, mainly forest growth, the sequestration potential of forest biomass by 2032 was estimated by M1 as 85.43 Tg, and by M2 to be substantially higher at 176.21 Tg. As of 2062, M1 estimated 155.97 Tg of sequestration potential for forest biomass. The spatial patterns of forest biomass and soil carbon density were closely related to climatic factors, and these relationships allowed the spatial division into two distinct climatic regions. Moreover, biomass carbon density was significantly correlated with the normalized difference vegetation index, soil silt, and elevation. This study provides key information for promoting the strategic shift from light-green to deep-green forest systems in Shannxi Province and updates the estimation methods of forest ecosystems' carbon pools based on field surveys.

Fast-Response Turn-on Fluorescent Probes Based on Thiolysis of NBD Amine for H2 S Bioimaging.

Hydrogen sulfide (H2 S) is an important endogenous signaling molecule with multiple biological functions. New selective fluorescent turn-on probes based on fast thiolyling of NBD (7-nitro-1,2,3-benzoxadiazole) amine were explored for sensing H2 S in aqueous buffer and in living cells. The syntheses of both probes are simple and quite straightforward. The probes are highly sensitive and selective toward H2 S over other biologically relevant species. The fluorescein-NBD-based probe showed 65-fold green fluorescent increase upon H2 S activation. The rhodamine-NBD-based probe reacted rapidly with H2 S (t1/2 ≈1 min) to give a 4.5-fold increase in red fluorescence. Moreover, both probes were successfully used for monitoring H2 S in living cells and in mice. Based on such probe-based tools, we could observe H2 O2 -induced H2 S biogenesis in a concentration-dependent and time-dependent fashion in living cells.

Tumour necrosis factor superfamily member 15 (Tnfsf15) facilitates lymphangiogenesis via up-regulation of Vegfr3 gene expression in lymphatic endothelial cells.

Lymphangiogenesis is essential in embryonic development but is rare in adults. It occurs, however, in many disease conditions including cancers. Vascular endothelial growth factor-C/D (VEGF-C/D) and VEGF receptor-3 (Vegfr3) play a critical role in the regulation of lymphangiogenesis. We investigated how the VEGF-C/Vegfr3 signalling system is regulated by tumour necrosis factor superfamily member 15 (Tnfsf15), an endothelium-derived cytokine. We report here that Tnfsf15, which is known to induce apoptosis in vascular endothelial cells, can promote lymphatic endothelial cell (LEC) growth and migration, stimulate lymphangiogenesis, and facilitate lymphatic circulation. Treatment of mouse LECs with Tnfsf15 results in up-regulation of Vegfr3 expression; this can be inhibited by gene silencing of death domain-containing receptor-3 (DR3; Tnfrsf25), a cell surface receptor for Tnfsf15, with siRNA, or by blocking Tnfsf15-DR3 interaction with a Tnfsf15 neutralizing antibody, 4-3H. Additionally, Tnfsf15/DR3 signalling pathways in LECs include activation of NF-κB. Tnfsf15-overexpressing transgenic mice exhibit a marked enhancement of lymph drainage; this is confirmed by treatment of wild-type mice with intraperitoneal injection of recombinant Tnfsf15. Moreover, systemic treatment of pregnant Tnfsf15 transgenic mice with 4-3H leads to inhibition of embryonic lymphangiogenesis. Our data indicate that Tnfsf15, a cytokine produced largely by endothelial cells, facilitates lymphangiogenesis by up-regulating Vegfr3 gene expression in LECs, contributing to the maintenance of the homeostasis of the circulatory system. This finding also suggests that Tnfsf15 may be of potential value as a therapeutic tool for the treatment of lymphoedema.

Microplastic pollution characteristics and ecological risk assessment in the Wuding River Basin, China.

Microplastics (MPs), as a new type of environmental pollutant, have attracted extensive attention in recent years. However, there has been relatively little research specifically focusing on MPs in the Yellow River Basin, China, particularly regarding MP migration patterns. Based on surface water and sediment samples from 19 sampling sites in the Wuding River (WDR), the abundances and characteristic distributions of MPs were analyzed, and the environmental factors affecting their distribution and potential ecological risks were evaluated. The results showed that the MP abundances in surface water and sediments of the WDR were significantly different (P < 0.05), with mean values of 2.98 ± 0.69 items/L and 419.47 ± 75.61 items/kg, respectively. In terms of MP characteristics, the most common size class was 0.1-0.5 mm in surface water. Polyethylene (PE, 32.50%) and polypropylene (PP, 27.50%) were the main polymer types of MPs in surface water. Although similar MP characteristics were observed in sediments, there were significantly more particles in the <0.1 mm particle size (P < 0.05), which was 15.0% higher than in surface water. Also, more high-density MP fragments were observed in sediment samples. The retention of MPs in sediments was influenced by the MP characteristics (density, shape, particle size) and sediment particle size. In contrast, the MP abundance in surface water was more closely related to the presence of other environmental pollutants, such as total phosphorus (WTP) and ammonia nitrogen (WAN). Temperature (T), agricultural land (AGR), and residential land (RES) only had significant effects on the distribution of MPs in surface water (P < 0.05). Potential ecological risk assessments revealed that MP pollution in sediments was more serious than in surface water, especially in the middle and lower reaches. The results of this study are important for understanding MP transport in a sandy river and for eliminating potential sources of MPs.

Dry and wet seasonal variations of the sediment fungal community composition in the semi-arid region of the Dali River, Northwest China.

Microbial communities play an important role in water quality regulation and biogeochemical cycling in freshwater ecosystems. However, there has been a lack of research on the seasonal variation of sediment microorganisms in the sediments of small river basins in typical semi-arid region. In this study, high-throughput DNA sequencing was used to investigate the fungal community and its influencing factors in the sediment of the Dali River in the dry and wet seasons. The results showed that there were obvious seasonal differences in fungal alpha diversity. The diversity and richness of fungi in the dry season were greater than that in the wet season, but the evenness of fungi in the dry season was lower than that in the wet season. In addition, Ascomycota and Basidiomycota were the most important phyla in the Dali River fungal community, but their distributions showed clear seasonal differences. In the dry season, the relative abundance of Ascomycota and Basidiomycota were 12.34-46.42% and 17.59-27.20%, respectively. In the wet season, the relative abundances of these two phyla were 24.33-36.56% and 5.75-12.26%, respectively. PICRUSt2 was used to predict the metabolic function of fungal community in the sediment, and it was found that at the first level, the proportion of biosynthesis in the dry season was higher than that in the wet season. The ecological network structure showed that the fungal community in the wet season was more complex and stable than that in the dry season. The characteristic fungi in the dry season sediment were chytrid fungi in the family Rhizophydiaceae and the order Rhizophydiales, whereas those in the wet season sediment were in the orders Eurotiales and Saccharomycetales. Canonical correspondence analysis (CCA) showed that the physicochemical properties of water and sediment together explained a greater proportion of the dry-season fungal community changes than of the wet-season changes. In the dry season, temperature and ammonia nitrogen in the water were the main factors affecting the change of fungal community, whereas in the wet season, total nitrogen concentration of the water, electrical conductivity, total organic carbon and available phosphorus of the sediment, pH, and temperature were the main factors affecting the changes in fungal community composition. The results of this study enhanced our understanding of microbial communities in semi-arid river ecosystems, and highlight the importance of the management and protection in river ecosystems.

Effects of comprehensive landscape patterns on water quality and identification of key metrics thresholds causing its abrupt changes.

Comprehensive landscape patterns influence water quality with multiple factors, complex processes, and scale dependence. However, studies identifying landscape thresholds causing abrupt water quality changes and characterizing the contribution of topography to water quality are still limited. Exploring the impact mechanisms of natural geographical and landscape characteristics on spatial and seasonal water quality variations is conducive to watershed water resource protection and ecosystem restoration. Based on water quality monitoring data of Minjiahe River in the typical headwater area of the upstream Dan River in China from 2019 to 2021, we employed redundancy analysis, partial redundancy analysis, and nonparametric change-point analysis to analyze the relationship between stream water quality and multi-spatial scale comprehensive landscape patterns, to obtain the interactive and independent contributions of different landscape categories at multi-spatial scales on water quality, and to find the key landscape threshold leading to abrupt changes in water quality. Results showed that landscape configuration, landscape composition, and topographic factors collectively explain over 89.1% of water quality variation. Most seasonal variations in water quality were primarily caused by landscape configuration. The landscape composition was mainly responsible for the differences in water quality variations among spatial scales. The topographic factors made the least independent contribution and had a potential impact on overall water quality variation. In order to protect the water quality of streams, it is more reasonable to regulate the landscape at different scales. At the sub-catchment scale, interspersion and juxtaposition index (IJI) and landscape shape index (LSI) should be controlled below 82% and 22. At the 100 m riparian scale, farmland, urban land, IJI, and LSI should be controlled below 29%, 6.5%, 92%, and 26, respectively. Our results provide important guidance for optimizing landscape patterns and water conservation in the watershed.

Response of water quality to land use in hydrologic response unit and riparian buffer along the Dan River, China.

Land uses determine water quality within riparian environments to a certain extent and directly affect human health via drinking water. The main objective of this paper is to investigate the influences of land use, both in hydrologic response units (HRUs) and 200-m-wide buffer areas, on surface water quality. The variations and interrelationships between water physicochemical properties and land uses were assessed for better management of water environment. Nitrogen was the dominant nutrient and was significantly correlated with other water quality parameters. In the HRUs and buffer areas, the dominant landscape was grassland and farmland, respectively. Total organic carbon (TOC) and dissolved oxygen (DO) had negative correlation with land use factors; nitrate nitrogen, total nitrogen, total phosphorus, electrical conductivity, and temperature, in contrast, were positively correlated with them. Industrial and residential land was the critical land use for the aquatic environment in the Dan River, indicating that point pollution should receive more attention. Vegetation area had strong regression relationships with TOC and DO. Furthermore, more specific types of land use (subcategory classification) had a greater role in water quality. The land use in buffers can act on the water body more directly and effectively.

Dynamic change of vegetation and its response to climate and topographic factors in the Xijiang River basin, China.

Vegetation plays an important role in the energy exchange, water cycle, carbon cycle, biogeochemical cycle, and maintenance of surface ecosystems. In recent years, regional vegetation cover has changed significantly. This study used statistical analyses, including the Mann-Kendall trend test, the Hurst exponent, and Pettitt test, to analyze the characteristics of temporal and spatial variation of vegetation coverage in the Xijiang River basin from 2000 to 2013. The results showed that vegetation coverage of 98.76% of the Xijiang River basin is weakly variable (Cv < 0.1). The area with significantly increased vegetation accounts for 43.45% of the total area (p < = 0.05). A total of 19.47% of vegetation coverage in the Xijiang River basin had significant change-points from 2004 to 2008 (p < = 0.05), and the area of concave change-points accounted for 25.99% of the total area of point increased the vegetation coverage. At an altitude of 500-2000 m, the altitude has an inhibitory effect on vegetation coverage. When the slope is less than 35 degrees, the slope has a promoting effect on vegetation coverage. Rich precipitation resources are the main source of soil water supply, and higher temperature provides better thermal energy resources, which may have a significant impact on vegetation growth in the future and cause time lag effects of climatic factors on vegetation coverage. The vegetation coverage and the area affected by the precipitation and temperature (time lag factors) accounted for 32.99% and 31.47% of the total watershed, respectively. The correlation between climatic factors, topographic factors, and vegetation coverage increased over time. The results from this study will help to further deepen the understanding of vegetation cover and its influencing factors, and provide a scientific basis for ecological restoration projects such as vegetation restoration in the Xijiang River basin of China.

Spatial Distribution Characteristics and Pollution Evaluation of Soil Iron in the Middle Hanjiang River.

Soil iron has an important impact on the ecological environment and on crop growth. This study selected a typical small watershed basin in the middle reaches of the Han River (Yujiehe) at Ankang City and used geostatistical methods and kriging interpolation to analyze the spatial distribution and structure of soil iron content for different land uses and at different depths, using the single-factor pollution evaluation to evaluate the pollution degree of soil iron. The results showed that soil iron in the Yujie River basin decreased with increasing soil depth, with contents of 8.80 mg/kg, 5.52 mg/kg, and 4.92 mg/kg at depths A1 (0-20 cm), A2 (20-40 cm), and A3 (40-60 cm). According to the classification index of effective trace elements in soil, the average contents of soil iron at these three depths were between 4.5 and 10 mg/kg, which are all considered moderate values. The coefficients of variation of soil iron at the three soil depths were 59%, 75%, and 83%, all of which showed moderate spatial variability, and the coefficient of variation increased gradually with soil depth. With semi-variance calculated at the three soil depths, soil iron optimal theoretical models were all exponential models with nugget coefficients of 9.52%, 47.76%, and 33.93%, indicating that spatial correlation was very strong in the A1 layer and moderate in the A2 and A3 layers. The spatial distribution of soil iron showed some variation in the study area, and the soil content was higher in the midwestern part in the A1 and A2 layers; however, in the A3 layer, the higher content was in the center and lower content was in the southern region. Correlations were significant between soil iron content on the one hand and land-use type and topographic factors on the other. The pollution indices of soil iron at the three soil depths under different land uses were all greater than 1.0, with the A1 layer in farmland being the worst, at 3.34. In the study area, using the background value of soil iron as an evaluation standard, the soil iron content of more than 65% of the Yujiehe region exceeded this standard.

Reducing Nitrogen and Phosphorus Losses from Different Crop Types in the Water Source Area of the Danjiang River, China.

Nitrogen and phosphorus are essential for plant growth and are the primary limiting nutrient elements. The loss of nitrogen and phosphorus in agricultural systems can cause the eutrophication of natural water bodies. In this paper, a field simulated rainfall experiment was conducted in a typical small watershed of the Danjiang River to study the nutrient loss process of nitrogen and phosphorus in slope croplands subjected to different crops and tillage measures. The characteristics of the runoff process and nutrient migration of different slope treatments were studied, which were the bare-land (BL, as the control), peanut monoculture (PL), corn monoculture (CL), bare land (upper slope) mixed with peanut monoculture (lower slope) (BP), corn and peanut intercropping (TCP), corn and soybean intercropping (TCS), downslope ridge cultivation (BS) slope, and straw-mulched (SC), respectively. The results showed that the runoff of CL, SC, TCS, BS, BP, PL and TCP slope types were 93%, 75%, 51%, 39%, 28%, 12%, and 6% of the those of the bare land, respectively. The total nitrogen concentration in runoff on different slope types decreased in the order of BP > PL > BS > SC > TCP > BL > CL > TCS. The BL was characterized with the highest NRL-TN (the loss of total nitrogen per unit area), with the value of 1.188 kg/hm2, while those of the TCP is the smallest with the value of 0.073 kg/hm2. The total phosphorus concentration in runoff decreasd in the order of BS > BP > PL > BL > TCP > SC > CL > TCS. The PRL-TP (the loss of total phosphorus per unit area) of BL is the largest (0.016 kg/hm2), while those of TCP is the smallest (0.001 kg/hm2). These indicate that the loss of nitrogen is much higer than that of phosphorus. The loss of nitrogen in runoff is dominated by nitrate nitrogen, which accounts for 54.4%-78.9% of TN. Slope croplands in the water source area should adopt the tillage measures of TCP and PL.These measures can reduce 85% of the runoff of nitrogen and phosphorus compared to the bare land. The results may assist in agricultural non-point source pollution control and help promote improved management of the water environment in the Danjiang River's water source area.

The effects of freeze-thaw process on soil water migration in dam and slope farmland on the Loess Plateau, China.

The seasonal freeze-thaw process affects soil water migration, which influence spring planting, especially in arid and semi-arid regions that cannot be irrigated on the Loess Plateau. This study was conducted to evaluate differences in the freeze-thaw process and water migration between dam farmland (DF) and slope farmland (SF). To accomplish this, two typical agricultural soils (DF and SF), soil water content (SWC) and soil temperature (ST) were monitored at different depths (15, 30, 60 and 90 cm), were investigated under freeze-thaw conditions from November 2015 to April 2016 in the Northwest China. The results showed that different freeze-thaw process between dam farmland (DF) and slope farmland (SF). The DF can keep soil water content resulting from longer frozen period. Thermal transmission between soil and air in SF is greater than that in DF. The SWC values in DF were higher than in SF at each depth layer under similar soil temperature. Migrated and incremental SWC in the DF is greater than that in SF during the freeze-thaw process. The initial SWC is the main impact on freeze-thaw process in this study. This research can provide useful information to guide the water management of seasonally frozen agricultural soil.

Distribution of soil organic carbon impacted by land-use changes in a hilly watershed of the Loess Plateau, China.

Vegetation restoration, terrace and check dam construction are the major measures for soil and water conservation on the Loess Plateau. These effective measures of stabilizing soils have significant impacts on soil organic carbon (SOC) distribution. However, following ecological construction, whether the hilly watershed acts as a source or a sink of soil carbon is still unknown. To understand the impact of land-use changes combined with check dam construction on SOC distribution, 1060 soil samples were collected from a 100 cm soil profile across a watershed on the Loess Plateau. The soils in the 0-20 cm layer had a higher SOC concentration than those of the 20-40, 40-60, 60-80 and 80-100 cm layers. Forestland, shrubland and terrace had significant higher SOC concentrations in the 0-20 cm soil layer than that of sloping cropland and dammed farmland (p < 0.05). SOC densities (0-100 cm) in terrace, forestland, shrubland, grassland, sloping cropland and dammed farmland were 12.09, 11.99, 11.89, 11.77, 11.41 and 10.11 kg m-2, respectively. These estimations suggested that SOC was redistributed in the watershed through land-use changes. Topographical factors, including altitude, aspect and slope had impacts on SOC concentrations. The application of hydrological controls to hillslopes and along river channels should be considered when assessing carbon sequestration within the soil erosion subsystem.

Runoff change and sediment source during rainstorms in an ecologically constructed watershed on the Loess Plateau, China.

The sediment-reducing effect of check dams and the safety issues following dam breaks are long-standing concerns. This study analyzed the runoff change and sediment source during rainstorms in a small watershed using a multivariate mixed model and a comparative analysis of watersheds. The problem of sediment loss from dammed farmland following check dam break during rainstorms was evaluated. The results showed that the flood peak lag time (PLT) was significantly influenced by pre-soil moisture in cases of small amounts of rainfall but not during rainstorms. Ecological construction significantly reduced the linear correlation between rainfall and runoff modulus (RM). The reduction in sediment delivery modulus (SDM) due to the check dam was more significant than that in RM. The reduction in RM and SDM under rainstorm conditions were 16%-74% and 53%-93%, respectively. The contributions of inter-gully and gully lands to the sediment deposited in dammed farmland during a large rainstorm on July 26, 2017 were 38.07% and 61.93%, respectively. Soil erosion remained significant during large rainstorms. The increase in vegetation coverage on the hill slope increased the amount of sediment from gully lands. Check dam breaches have accounted for a loss of only 1.2% of the total area of the dammed farmland, and thus have not caused a large loss of sediment. However, breaches in them clearly increased the coefficient of variation of RM and SDM. Therefore, check dams have a critical effect on controlling sediment delivery at the watershed scale. Dam breaks do not result in a large percentage of sediment loss in the dammed farmland.

Vegetation Change and Its Relationship with Climate Factors and Elevation on the Tibetan Plateau.

As the "roof of the world", the Tibetan Plateau (TP) is a unique geographical unit on Earth. In recent years, vegetation has gradually become a key factor reflecting the ecosystem since it is sensitive to ecological changes especially in arid and semi-arid areas. Based on the normalized difference vegetation index (NDVI) dataset of TP from 2000 to 2015, this study analyzed the characteristics of vegetation variation and the correlation between vegetation change and climatic factors at different time scales, based on a Mann-Kendall trend analyses, the Hurst exponent, and the Pettitt change-point test. The results showed that the vegetation fractional coverage (VFC) generally increased in the past 16 years, with 60.3% of the TP experiencing an increase, of which significant (p < 0.05) increases accounted for 28.79% and were mainly distributed in the north of the TP. Temperature had the largest response with the VFC on the seasonal scale. During the growing season, the correlation between precipitation and sunshine duration with VFC was high (p < 0.05). The change-points of the VFC were mainly distributed in the north of the TP during 2007-2009. Slope and elevation had an impact on the VFC; the areas with large vegetation change are mainly distributed in slopes <20° and elevation of 3000-5000 m. For elevation above 3000-4000 m, the response of the VFC to precipitation and temperature was the strongest. This study provided important information for ecological environment protection and ecosystem degradation on the Tibetan Plateau.

Comparing watershed afforestation and natural revegetation impacts on soil moisture in the semiarid Loess Plateau of China.

Two contiguous watersheds in the Loess Plateau in China that differed in the way their vegetation had been restored-afforestation or natural revegetation-differed in their consumption of soil moisture: the afforested watershed consumed more soil moisture, although the difference was significant only in wet years. Yet, both the afforestation and natural revegetation did not induce the soil desiccation in the study area. In the afforested watershed, soil moisture was depleted even beyond a depth of 100 cm, whereas in the grassland (natural revegetation), the depletion was confined to a layer less than 60 cm deep. Rainfall in the growing season accounted for 46-60% of the variation in soil moisture in the 0-60 cm layer in the grassland, but only 22-39% of that in the forest land. Overall, afforestation is the better option for the Loess Plateau only in areas where the annual rainfall is more than 500 mm. In any attempt at revegetation, the choice of tree species and planting densities should match the carrying capacity of the region's water resources.

Vascular endothelial growth factor suppresses TNFSF15 production in endothelial cells by stimulating miR-31 and miR-20a expression via activation of Akt and Erk signals.

Tumor necrosis factor superfamily-15 (TNFSF15; VEGI; TL1A) is a negative modulator of angiogenesis for blood vessel homeostasis and is produced by endothelial cells in a mature vasculature. It is known to be downregulated by vascular endothelial growth factor (VEGF), a major regulator of neovascularization but the mechanism of this interaction is unclear. Here we report that VEGF is able to stimulate the production of two microRNAs, miR-20a and miR-31, which directly target the 3'-UTR of TNFSF15. Additionally, we show that two VEGF-stimulated cell growth signals, Erk and Akt, are responsible for promoting the expression of miR-20a and miR-31. Treatment of human umbilical vein endothelial cells (HUVECs) with Akt inhibitor LY294002 results in diminished miR-20a and miR-31 production, while Erk inhibitor U0126 prevented VEGF-stimulated expression of miR-20a but not that of miR-31. Furthermore, inactivation of either Erk or Akt signals restores TNFSF15 gene expression. In an angiogenesis assay, elevated miR-20a or miR-31 levels in HUVECs leads to enhancement of capillary-like tubule formation in vitro, whereas lowered miR-20a and miR-31 levels results in an inhibition. These findings are consistent with the view that miR-20a and miR-31 mediate VEGF-induced downregulation of TNFSF15. Targeting these microRNA molecules may therefore provide an effective approach to inhibit angiogenesis.

TNFSF15 suppresses VEGF production in endothelial cells by stimulating miR-29b expression via activation of JNK-GATA3 signals.

Vascular endothelial cell growth factor (VEGF) plays a pivotal role in promoting neovascularization. VEGF gene expression in vascular endothelial cells in normal tissues is maintained at low levels but becomes highly up-regulated in a variety of disease settings including cancers. Tumor necrosis factor superfamily 15 (TNFSF15; VEGI; TL1A) is an anti-angiogenic cytokine prominently produced by endothelial cells in a normal vasculature. We report here that VEGF production in mouse endothelial cell line bEnd.3 can be inhibited by TNFSF15 via microRNA-29b (miR-29b) that targets the 3'-UTR of VEGF transcript. Blocking TNFSF15 activity by using either siRNA against the TNFSF15 receptor known as death domain-containing receptor-3 (DR3; TNFRSF25), or a neutralizing antibody 4-3H against TNFSF15, led to inhibition of miR-29b expression and reinvigoration of VEGF production. In addition, we found that TNFSF15 activated the JNK signaling pathway as well as the transcription factor GATA3, resulting in enhanced miR-29b production. Treatment of the cells either with SP600125, an inhibitor of JNK, or with JNK siRNA, led to eradication of TNFSF15-induced GATA3 expression. Moreover, GATA3 siRNA suppressed TNFSF15-induced miR-29b expression. These findings suggest that VEGF gene expression can be suppressed by TNFSF15-stimulated activation of the JNK-GATA3 signaling pathway which gives rise to up-regulation of miR-29b.

Dual-Reactable Fluorescent Probes for Highly Selective and Sensitive Detection of Biological H2 S.

Hydrogen sulfide (H2 S) is an important endogenous signaling molecule with a variety of biological functions. Development of fluorescent probes for highly selective and sensitive detection of H2 S is necessary. We show here that dual-reactable fluorescent H2 S probes could react with higher selectivity than single-reactable probes. One of the dual-reactable probes gives more than 4000-fold turn-on response when reacting with H2 S, the largest response among fluorescent H2 S probes reported thus far. In addition, the probe could be used for high-throughput enzymatic assays and for the detection of Cys-induced H2 S in cells and in zebrafish. These dual-reactable probes hold potential for highly selective and sensitive detection of H2 S in biological systems.