Regulatory networks of the F-box protein FBX206 and OVATE family proteins modulate brassinosteroid biosynthesis to regulate grain size and yield in rice.

F-box proteins participate in the regulation of many processes, including cell division, development, and plant hormone responses. Brassinosteroids (BRs) regulate plant growth and development by activating core transcriptional and other multiple factors. In rice, OVATE family proteins (OFPs) participate in BR signalling and regulate grain size. Here we identified an F-box E3 ubiquitin ligase, FBX206, that acts as a negative factor in BR signalling and regulates grain size and yield in rice. Suppressed expression of FBX206 by RNAi leads to promoted plant growth and increased grain yield. Molecular analyses showed that the expression levels of BR biosynthetic genes were up-regulated, whereas those of BR catabolic genes were down-regulated in FBX206-RNAi plants, resulting in the accumulation of 28-homoBL, one of the bioactive BRs. FBX206 interacted with OsOFP8, a positive regulator in BR signalling, and OsOFP19, a negative regulator in BR signalling. SCFFBX206 mediated the degradation of OsOFP8 but suppressed OsOFP19 degradation. OsOFP8 interacted with OsOFP19, and the reciprocal regulation between OsOFP8 and OsOFP19 required the presence of FBX206. FBX206 itself was ubiquitinated and degraded, but interactions of OsOFP8 and OsOFP19 synergistically suppressed the degradation of FBX206. Genetic interactions indicated an additive effect between FBX206 and OsOFP8 and epistatic effects of OsOFP19 on FBX206 and OsOFP8. Our study reveals the regulatory networks of FBX206, OsOFP8, and OsOFP19 in BR signalling that regulate grain size and yield in rice.

Integrating suitable habitat dynamics under typical hydrological regimes as guides for the conservation and restoration of different waterbird groups.

The operation of the Three Gorges Project (TGP) has influenced the wetland ecosystems downstream, thereby affecting the distribution of habitats suitable for waterbirds. However, dynamic studies on habitat distribution under different water regimes are lacking. Here, using data from three successive wintering periods representing three typical water regimes, we modelled and mapped the habitat suitability of three waterbird groups in Dongting Lake, which is the first river-connected lake downstream of the TGP, and a crucial wintering ground for waterbirds along the East Asian-Australasian Flyway. The results showed that the spatial pattern of habitat suitability varied among the wintering periods and waterbird groups. The analysis estimated the largest suitable habitat area for the herbivorous/tuber-eating group (HTG) and the insectivorous waterbird group (ING) under a normal water recession pattern, whereas early water recession had a more adverse effect. The suitable habitat area for the piscivorous/omnivorous group (POG) was higher under late water recession than under normal conditions. The ING was the most affected by hydrological changes among the three waterbird groups. Further, we identified the key conservation and potential restoration habitats. The HTG exhibited the largest key conservation habitat area compared to the other two groups, while the ING showed a potential restoration habitat area larger than its key conservation habitat area, indicating its sensitivity to environmental changes. The optimal inundation durations from September 1 to January 20 for HTG, ING and POG were 52 ± 7 d, 68 ± 18 d, and 132 ± 22 d, respectively. Therefore, the water recession starting in mid-October may be favourable for waterbirds in Dongting Lake. Altogether, our results can be used as guidance for prioritising certain management actions for waterbird conservation. Moreover, our study highlighted the importance of considering habitat spatiotemporal variation in highly dynamic wetlands when implementing management practices.

Transition Metal Catalysts for Atmospheric Heavy Metal Removal: A Review of Current Innovations and Advances.

Atmospheric heavy metal pollution presents a severe threat to public health and environmental stability. Transition metal catalysts have emerged as a potent solution for the selective capture and removal of these pollutants. This review provides a comprehensive summary of current advancements in the field, emphasizing the efficiency and specificity of nanostructured transition metals, including manganese, iron, cobalt, nickel, copper, and zinc. Looking forward, we delve into the prospective trajectory of catalyst development, underscoring the need for materials with enhanced stability, regenerability, and environmental compatibility. We project that advancements in computational materials science, nanotechnology, and green chemistry will be pivotal in discovering innovative catalysts that are economically and environmentally sustainable. The integration of smart technologies for real-time monitoring and adaptive control is anticipated to revolutionize heavy metal remediation, ensuring efficient and responsive pollution abatement strategies in the face of evolving industrial scenarios and regulatory landscapes.

Opposite effects of nutrient enrichment and an invasive snail on the growth of invasive and native macrophytes.

Many ecosystems are now co-invaded by alien plant and herbivore species. The evolutionary naivety of native plants to alien herbivores can make the plants more susceptible to the detrimental effects of herbivory than co-occurring invasive plants, in accordance with the apparent competition hypothesis. Moreover, the invasional meltdown hypothesis predicts that in multiply invaded ecosystems, invasive species can facilitate each other's impacts on native communities. Although there is growing empirical support for these hypotheses, facilitative interactions between invasive plants and herbivores remain underexplored in aquatic ecosystems. Many freshwater ecosystems are co-invaded by aquatic macrophytes and mollusks and simultaneously experience nutrient enrichment. However, the interactive effects of these ecological processes on native macrophyte communities remain an underexplored area. To test these effects, we performed a freshwater mesocosm experiment in which we grew a synthetic native community of three macrophyte species under two levels of invasion by an alien macrophyte Myriophyllum aquaticum (invasion vs. no invasion) and fully crossed with two levels of nutrient enrichment (enrichment vs. no enrichment) and herbivory by an invasive snail Pomacea canaliculata (herbivory vs. no herbivory). In line with the invasional meltdown and apparent competition hypotheses, we found that the proportional aboveground biomass yield of the invasive macrophyte, relative to that of the native macrophyte community, was significantly greater in the presence of the invasive herbivore. Evidence of a reciprocal facilitative effect of the invasive macrophyte on the invasive herbivore is provided by results showing that the herbivore produced greater egg biomass in the presence versus in the absence of M. aquaticum. However, nutrient enrichment reduced the mean proportional aboveground biomass yield of the invasive macrophyte. Our results suggested that herbivory by invader P. canaliculata may enhance the invasiveness of M. aquaticum. However, nutrient enrichment of habitats that already harbor M. aquaticum may slow down the invasive spread of the macrophyte. Broadly, our study underscores the significance of considering several factors and their interactions when assessing the impact of invasive species, especially considering that many habitats experience co-invasion by plants and herbivores and simultaneously undergo various other disturbances, including nutrient enrichment.

Determination of organophosphate flame retardant tris(2-chloroethyl)phosphine based on the luminol-H2 O2 chemiluminescence system.

Organophosphorus flame retardants (OPFRs) are new types of environmental pollutants, therefore the rapid and sensitive detection of OPFRs is a very important objective. A new experimental phenomenon was found in which tris(2-chloroethyl)phosphine (TCEP), a type of OPFR, could effectively enhance the signal of the luminol-H2 O2 chemiluminescence (CL) system. Combined with the controllability of flow injection analysis, a rapid, stable, and sensitive CL method was established. The CL intensity responded linearly to the concentration of TCEP in the range 0.5-100 µg/L (R2 = 0.999) with a low detection limit of 33 ng/L. Relative standard deviation (RSD) was 2.2% (n = 7, c = 100 µg/L). Water samples were labelled and recycled with RSDs of 1.1-5.7% and recoveries of 88.7-116.1%. Based on these results, this study established a new CL detection method for the environmental pollutant TCEP.

Traditional Chinese medicine symptom normalization approach leveraging hierarchical semantic information and text matching with attention mechanism.

Traditional Chinese medicine (TCM) symptom normalization is difficult because the challenges of the symptoms having different literal descriptions, one-to-many symptom descriptions and different symptoms sharing a similar literal description. We propose a novel two-step approach utilizing hierarchical semantic information that represents the functional characteristics of symptoms and develop a text matching model that integrates hierarchical semantic information with an attention mechanism to solve these problems. In this study, we constructed a symptom normalization dataset and a TCM normalization symptom dictionary containing normalization symptom words, and assigned symptoms into 24 classes of functional characteristics. First, we built a multi-label text classifier to isolate the hierarchical semantic information from each symptom description and count the corresponding normalization symptoms and filter the candidate set. Then we designed a text matching model of mixed multi-granularity language features with an attention mechanism that utilizes the hierarchical semantic information to calculate the matching score between the symptom description and the normalization symptom words. We compared our approach with other baselines on real-world data. Our approach gives the best performance with a Hit@ 1, 3, and 10 of 0.821, 0.953, and 0.993, respectively, and a MeanRank of 1.596, thus outperforming significantly regarding the symptom normalization task. We developed an approach for the TCM symptom normalization task and demonstrated its superior performance compared with other baselines, indicating the promise of this research direction.

Automated detection and quantification of COVID-19 pneumonia: CT imaging analysis by a deep learning-based software.

BACKGROUND: The novel coronavirus disease 2019 (COVID-19) is an emerging worldwide threat to public health. While chest computed tomography (CT) plays an indispensable role in its diagnosis, the quantification and localization of lesions cannot be accurately assessed manually. We employed deep learning-based software to aid in detection, localization and quantification of COVID-19 pneumonia. METHODS: A total of 2460 RT-PCR tested SARS-CoV-2-positive patients (1250 men and 1210 women; mean age, 57.7 ± 14.0 years (age range, 11-93 years) were retrospectively identified from Huoshenshan Hospital in Wuhan from February 11 to March 16, 2020. Basic clinical characteristics were reviewed. The uAI Intelligent Assistant Analysis System was used to assess the CT scans. RESULTS: CT scans of 2215 patients (90%) showed multiple lesions of which 36 (1%) and 50 patients (2%) had left and right lung infections, respectively (> 50% of each affected lung's volume), while 27 (1%) had total lung infection (> 50% of the total volume of both lungs). Overall, 298 (12%), 778 (32%) and 1300 (53%) patients exhibited pure ground glass opacities (GGOs), GGOs with sub-solid lesions and GGOs with both sub-solid and solid lesions, respectively. Moreover, 2305 (94%) and 71 (3%) patients presented primarily with GGOs and sub-solid lesions, respectively. Elderly patients (≥ 60 years) were more likely to exhibit sub-solid lesions. The generalized linear mixed model showed that the dorsal segment of the right lower lobe was the favoured site of COVID-19 pneumonia. CONCLUSION: Chest CT combined with analysis by the uAI Intelligent Assistant Analysis System can accurately evaluate pneumonia in COVID-19 patients.

IL33 activates CD8+T and NK cells through MyD88 pathway to suppress the lung cancer cell growth in mice.

OBJECTIVE: In this study, we observed the effects of IL-33 on tumor immune response in lung cancer-bearing mice using wild type and MyD88-/- mice respectively. METHODS: Wild C57BL/6 (C57BL/6WT), MyD88 knockout C57BL/6 mice (C57BL/6 MyD88-/-) and Lewis cells were used in this study. Cell proliferation, cytokine release and cytotoxicity were detected. RESULTS: IL-33 could significantly up-regulate specific cellular immunity, inhibit tumor growth and improve survival time in wild type mice group, and it had dose dependent effect. However, IL-33 had no effect on cell immunity and tumor growth in MyD88-/- mice group. Compared with MyD88-/- mice, IL-33 could significantly increase the ratio of CD8+T cells to neutrophils in wild type mice, while the percentage of tumor infiltrating CD11b+ cells, Mo-MDSC, F4/80+ macrophages and mDC cells decreased significantly in wild type mice group. IL-33 could upregulate the expression of CD107a and IFN-γ in CD8+T cells and NK cells of wild type mice, while IL-33 could not upregulate them in MyD88-/- mice. IL-33 could upregulate the expression of CD40, CD80, CD86 and CD205 in DC cells in wild type mice, induce T cells to differentiate into Th1 cells and enhance tumor cell immunity. CONCLUSIONS: IL-33 could promote differentiation and maturation of DC cells through MyD88 pathway, up-regulate the tumor immunity of CD8+T cells and NK cells, and inhibit the proliferation of lung cancer cells.

Management of Persistent Air Leaks Using Endobronchial Autologous Blood Patch and Spigot Occlusion: A Multicentre Randomized Controlled Trial in China.

BACKGROUND: Optimal management of persistent air leaks (PALs) in patients with secondary spontaneous pneumothorax (SSP) remains controversial. OBJECTIVE: To evaluate the efficacy and safety of endobronchial autologous blood plus thrombin patch (ABP) and bronchial occlusion using silicone spigots (BOS) in patients with SSP accompanied by alveolar-pleural fistula (APF) and PALs. METHODS: This prospective multicentre randomized controlled trial compared chest tube-attached water-seal drainage (CTD), ABP, and BOS that were performed between February 2015 and June 2017 in one of six tertiary care hospitals in China. Patients diagnosed with APF experiencing PALs (despite 7 days of CTD) and inoperable patients were included. Outcome measures included success rate of pneumothorax resolution at the end of the observation period (further 14 days), duration of air leak stop, lung expansion, hospital stay, and complications. RESULTS: In total, 150 subjects were analysed in three groups (CTD, ABP, BOS) of 50 each. At 14 days, 60, 82, and 84% of CTD, ABP, and BOS subjects, respectively, experienced full resolution of pneumothorax (p = 0.008). All duration outcome measures were significantly better in the ABP and BOS groups than in the CTD group (p < 0.016 for all). The incidence of adverse events, including chest pain, cough, and fever, was not significantly different. All subjects in the ABP and BOS groups experienced temporary haemoptysis. Spigot displacement occurred in 8% of BOS subjects. CONCLUSION: ABP and BOS resulted in clinically meaningful outcomes, including higher success rate, duration of air leak stop, lung expansion, and hospital stay, with an acceptable safety profile.

Use of Interferon-γ release assay for the diagnosis of female genital tuberculosis in Northwest China.

BACKGROUND: Female genital tuberculosis (FGTB) is one of the major causes of infertility. However, nonspecific manifestations and the lack of easy access to gold-standard diagnostic test render a diagnostic difficult for FGTB. The objective of this study was to determine T-SPOT.TB (an interferon-γ release assay, IGRA) performance in patients with FGTB. METHODS: A total of 213 female patients with validated T-SPOT.TB results were recruited in this retrospective study. Among which, 103 were confirmed FGTB, and 110 were excluded from tuberculosis (control). Of the confirmed FGTB patients, 52 were confirmed by microbiologically/histopathologically examination, while the remaining 51 were clinically confirmed (successfully responsive to anti-tuberculosis treatment). T-SPOT.TB test was performed in both FGTB and control group during the diagnostic procedure. RESULTS: The overall sensitivity and specificity of T-SPOT.TB were 86.41% and 75.45% respectively. Sensitivity of T-SPOT.TB was significantly higher when compared with conventional tuberculosis diagnostic tests. Moreover, T-SPOT.TB test using pelvic effusion (PE) showed higher sensitivity than using corresponding peripheral blood (PB) (94.44% vs 72.22%, P < 0.001). Mean value of spot forming cells (SFCs) of T-SPOT.TB using PE was significantly higher than that of PB in FGTB group (193 (IQR 105-280) SFCs/2.5 × 105 PEMCs vs 71 (IQR 36-107) SFCs/2.5 × 105 PBMCs, P = 0.01), while this was not detected in control group (11 (IQR 0-22) SFCs/2.5 × 105 PEMCs vs 9 (IQR 0-18) SFCs/2.5 × 105 PBMCs, P = 0.77). CONCLUSION: These results demonstrated that T-SPOT.TB, especially PE T-SPOT.TB, is an useful adjunct in FGTB diagnosis.

Antimicrobial Activity of Galangin and Its Effects on Murein Hydrolases of Vancomycin-Intermediate Staphylococcus aureus (VISA) Strain Mu50.

Backgroud: Antibiotic treatment for infections caused by vancomycin-intermediate Staphylococcus aureus (VISA) strains is challenging, and only a few effective and curative methods have been developed to combat these strains. This study aimed to investigate the antimicrobial activity of galangin against S. aureus and its effects on the murein hydrolases of VISA strain Mu50. This is the first report on these effects of galangin, and it may help to improve the treatment for VISA infections by demonstrating the effective use of galangin. METHODS: Firstly, the minimum inhibitory concentration (MIC) and growth curve were used to investigate the antimicrobial activity of galangin against S. aureus. Secondly, transmission electron microscopy (TEM) was used to observe morphological changes of VISA strain Mu50. Thirdly, Triton X-100-induced autolysis and cell wall hydrolysis assays were performed to determine the activities of the murein hydrolases of Mu50. Finally, fluorescence real-time quantitative PCR was used to investigate the expression of the murein hydrolase-related Mu50 genes. RESULTS: The results indicated that the MIC of galangin was 32 µg/mL against ATCC25293, N315, and Mu50, and galangin could significantly suppress the bacterial growth (p < 0.05) with concentrations of 4, 8 and 16 µg/mL, compared with control group (0 µg/mL). To explore the possible reasons of bacteriostatic effects of galangin, we observed morphological changes using TEM which showed that the division of Mu50 daughter cells treated with galangin was obviously inhibited. Considering the vital role of murein hydrolases in cellular division, assays were performed, and galangin markedly decreased Triton X-100-induced autolysis and cell wall hydrolysis. Galangin also significantly inhibited the expression of the murein hydrolase genes (atl, lytM, and lytN) and their regulatory genes (cidR, cidA, and cidB). CONCLUSIONS: Our findings indicated that galangin can effectively inhibit murein hydrolase activity as well as the growth of VISA strain Mu50.

Colorimetric determination of Hg(II) via the gold amalgam induced deaggregation of gold nanoparticles.

A method is described for the colorimetric determination of mercury(II). In the absence of Hg(II), aminopropyltriethoxysilane (APTES) which is positively charged at pH 7 is electrostatically absorbed on the surface of gold nanoparticles (AuNPs). This neutralizes the negative charges of the AuNPs and leads to NP aggregation and a color change from red to blue-purple. However, in the presence of Hg(II), reduced Hg (formed through the reaction between Hg(II) and citrate on the AuNP surface) will replace the APTES on the AuNPs. Hence, the formation of aggregates is suppressed and the color of the solution does not change. The assay is performed by measuring the ratio of absorbances at 650 and 520 nm and can detect Hg(II) at nanomolar levels with a 10 nM limit of detection. The specific affinity between mercury and gold warrants the excellent selectivity for Hg(II) over other environmentally relevant metal ions. Graphical Abstract Schematic of the method for determination of Hg2+ based on the gold amalgam-induced deaggregation of gold nanoparticles in the presence of APTES with the LOD of 10.1 nM.

Electron Acceptors Induce Secretion of Enterotoxigenic Escherichia coli Heat-Labile Enterotoxin under Anaerobic Conditions through Promotion of GspD Assembly.

Heat-labile enterotoxin (LT), the major virulence factor of enterotoxigenic Escherichia coli (ETEC), can lead to severe diarrhea and promotes ETEC adherence to intestinal epithelial cells. Most previous in vitro studies focused on ETEC pathogenesis were conducted under aerobic conditions, which do not reflect the real situation of ETEC infection because the intestine is anoxic. In this study, the expression and secretion of LT under anaerobic or microaerobic conditions were determined; LT was not efficiently secreted into the supernatant under anaerobic or microaerobic conditions unless terminal electron acceptors (trimethylamine N-oxide dihydrate [TMAO] or nitrate) were available. Furthermore, we found that the restoration effects of TMAO and nitrate on LT secretion could be inhibited by amytal or ΔtorCAD and ΔnarG E. coli strains, indicating that LT secretion under anaerobic conditions was dependent on the integrity of the respiratory chain. At the same time, electron acceptors increase the ATP level of ETEC, but this increase was not the main reason for LT secretion. Subsequently, the relationship between the integrity of the respiratory chain and the function of the type II secretion system was determined. The GspD protein, the secretin of ETEC, was assembled under anaerobic conditions and was accompanied by LT secretion when TMAO or nitrate was added. Our data also demonstrated that TMAO and nitrate could not induce the GspD assembly and LT secretion in ΔtorCAD and ΔnarG strains, respectively. Moreover, GspD assembly under anaerobic conditions was assisted by the pilot protein YghG.

Lewis Lung Cancer Cells Promote SIGNR1(CD209b)-Mediated Macrophages Polarization Induced by IL-4 to Facilitate Immune Evasion.

Tumor-associated macrophages are a prominent component of lung cancer and contribute to tumor progression by facilitating the immune evasion of cancer cells. DC-SIGN (CD209) assists in the immune evasion of a broad spectrum of pathogens and neoplasms by inhibiting the maturation of DCs and subsequent cytokines production. However, the expression of DC-SIGN in macrophages and its role in mediating immune evasion in lung cancer and the underlying mechanism remain unclear. Our study aimed to identify the immunosuppressive role of SIGNR1 in murine macrophage differentiation and lung cancer progression. We found that SIGNR1-positive RAW264.7 macrophages were enriched in mixed cultures with Lewis lung cancer cells (LLC) (ratio of RAW 264.7 to LLC being 1:1) after stimulation with IL-4. Moreover, LLC-educated macrophages exhibited significantly higher levels of IL-10 but lower IL-12 in response to IL-4 treatment as determined by RT-PCR and ELISA. However, inhibition of SIGNR1 markedly hampered the production of IL-10, indicating that SIGNR1 was indispensable for IL-4+LLC induced macrophage polarization towards the M2 subtype. Furthermore, polarized M2 cells immersed in a tumor microenvironment promoted the migration of LLCs, as measured by transwell assays, but migration was suppressed after blockade of SIGNR1 using CD209b antibody. In addition, IL-4+LLC-educated macrophages reduced the proliferation of the activated T cells and reduced IFN-γ-mediated Th1 response in T cells, while SIGNR1 inhibition rescued Th1 cell functions. In conclusion, murine SIGNR1 expressed in LLC-educated macrophages appears to mediate IL-4-induced RAW264.7 macrophage polarization and thus facilitate lung cancer evasion.

The effects of Gremlin1 on human umbilical cord blood hematopoietic progenitors.

Bone morphogenetic proteins (BMPs) support malignant hematopoiesis in CML. Conversely, the multi-functional BMP antagonist Gremlin1 supports self-renewing cancer stem cells of other malignancies. Inhibition of BMP signaling in CML, or of Gremlin1 in solid tumors, may therefore have therapeutic potential. However, since BMPs regulate hematopoietic stem cell (HSC) decisions in the stem cell niche, it is necessary to determine how Gremlin1 influences normal HSC. We examined the effects of Gremlin1 on long-term culture-initiating cells (LTC-IC) and transplantable hematopoietic stem cells (SCID-repopulating cells: SRC) in human umbilical cord blood. Gremlin1 inhibited BMP signaling, downregulated BMP-6 and cyclin E2 expression and upregulated hairy and enhancer of split-1 (HES-1; a Notch transcriptional target) and Hedgehog interacting protein-1 (HHIP-1; an inhibitor of Hedgehog signaling). The functional effects of Gremlin1 on SRC, i.e. skewing of their myelopoietic:lymphopoietic potential towards B lymphopoiesis without affecting long-term engraftment potential, were entirely consistent with changes in gene expression induced by Gremlin1. Since both BMPs and Gremlin1 are secreted by osteoblasts in vivo, our studies provide potential insights into the molecular regulation of hematopoiesis in the stem cell niche. These results also suggest that Gremlin1 (and possibly its mimetics that may be developed for therapeutic use) may not adversely affect normal human hematopoietic stem cell survival, though they may reduce their myelopoietic potential.

Epigallocatechin-3-gallate ameliorates seawater aspiration-induced acute lung injury via regulating inflammatory cytokines and inhibiting JAK/STAT1 pathway in rats.

Signal transducers and activators of transcriptions 1 (STAT1) play an important role in the inflammation process of acute lung injury (ALI). Epigallocatechin-3-gallate (EGCG) exhibits a specific and strong anti-STAT1 activity. Therefore, our study is to explore whether EGCG pretreatment can ameliorate seawater aspiration-induced ALI and its possible mechanisms. We detected the arterial partial pressure of oxygen, lung wet/dry weight ratios, protein content in bronchoalveolar lavage fluid, and the histopathologic and ultrastructure staining of the lung. The levels of IL-1, TNF-α, and IL-10 and the total and the phosphorylated protein level of STAT1, JAK1, and JAK2 were assessed in vitro and in vivo. The results showed that EGCG pretreatment significantly improved hypoxemia and histopathologic changes, alleviated pulmonary edema and lung vascular leak, reduced the production of TNF-α and IL-1, and increased the production of IL-10 in seawater aspiration-induced ALI rats. EGCG also prevented the seawater aspiration-induced increase of TNF-α and IL-1 and decrease of IL-10 in NR8383 cell line. Moreover, EGCG pretreatment reduced the total and the phosphorylated protein level of STAT1 in vivo and in vitro and reduced the phosphorylated protein level of JAK1 and JAK2. The present study demonstrates that EGCG ameliorates seawater aspiration-induced ALI via regulating inflammatory cytokines and inhibiting JAK/STAT1 pathway in rats.

Spatiotemporal characteristics and drivers of ecosystem service interactions in the Dongting Lake Basin.

Uncovering the spatiotemporal features of ecosystem services (ESs) and their intricate interrelations in large lake basins can facilitate the development of scientific management measures for various ESs. Previous studies have focused less on watershed units and their historical dynamics, and the ecosystem service (ES) driving mechanisms remain unclear. Here, we focused on Hunan Province-the main coverage area of the Dongting Lake Basin (China's second largest freshwater lake), investigated the spatiotemporal characteristics of seven typical ESs and their interactions, identified the ecosystem service bundle (ESB) historical spatial patterns and revealed the socio-ecological driving mechanisms of these ES changes. Results showed that: (1) the spatial distribution of most ESs remained stable in the basin. Food production (FP), water yield (WY), soil conservation (SC) and net primary productivity (NPP) improved over time, whereas nitrogen retention (NR), habitat quality (HQ) and outdoor recreation (OR) declined; (2) tradeoffs were observed between food production and most ESs, whereas synergistic relationships between all ESs except food production. The tradeoff relationship between food production and water yield increased significantly over time, while the synergistic relationship between water yield and nitrogen retention decreased significantly; (3) five ecosystem service bundles were identified. And the transformation of soil conservation area into integrated ecological regulation area mainly occurred from 2000 to 2020, resulting in an increase in the function of ecological regulation services; (4) natural conditions such as precipitation, topography and vegetation, as well as socio-economic factors such as Gross Domestic Product (GDP) and population, were key factors affecting ESs. The interactions among most of these drivers can further elucidate the ES changes. Our results emphasize the need for a watershed-based assessment and a historical dynamic perspective in the sustainable management of ESs.

Vegetation types and flood water level are dominant factors controlling the carbon sequestration potential in Dongting Lake floodplain, China.

Wetlands are important carbon sinks. However, the carbon sequestration potential of flooded wetlands may be weakened owing to water regime changes induced by anthropogenic disturbances. Using the eddy covariance technique, this study quantified the effects of the water level and vegetation types on the net ecosystem CO2 exchange (NEE), gross primary production (GPP), and ecosystem respiration (Reco) from a reed marsh (Miscanthus sacchariflorus) and a sedge meadow (Carex spp.) in the Dongting Lake floodplain from 2014 to 2016. Our results indicated that the sedge meadow (-89.49 to -186.47 g C m-2 y-1) and reed marsh (-246.12 to -513.94 g C m-2 y-1) were carbon sinks on the interannual timescale. However, the sedge meadow changed from a carbon sink to a carbon source during the flooding season. The effect of flooding on the carbon sink function in the reed marsh was dependent on the water level. The carbon sink function of the reed marsh was enhanced by moderate flooding (water level under 30.5 m in Chenglingji) owing to the inhibition of Reco, but was weakened by extremely high-water levels (over 33 m in Chenglingji) during the flooding season. Seasonal variations in NEE, GPP, and Reco were closely related to photosynthetic photon flux density, soil water content, water level, soil temperature, and air temperature. We can conclude that the increase in reed area combined with the decrease in flooding days in the sedge meadow can potentially enhance the carbon sink function of the Dongting Lake floodplain.

[Effects of Modified Distillers' Grains Biochar on Cadmium Forms in Purple Soil and Cadmium Uptake by Rice].

Biochar and modified biochar have been widely used as remediation materials in heavy metal-contaminated agricultural soils. In order to explore economical and effective materials for the remediation of cadmium (Cd)-contaminated acidic purple soil, distillers 'grains were converted into distillers' grains biochar (DGBC) and modified using nano-titanium dioxide (Nano-TiO2) to produce two types of modified DGBCs:TiO2/DGBC and Fe-TiO2/DGBC. A rice pot experiment was used to investigate the effects of different biochar types and application rates (1%, 3%, and 5%) on soil properties, nutrient content, Cd bioavailability, Cd forms, rice growth, and Cd accumulation. The results showed that:① DGBC application significantly increased soil pH, cation exchange capacity (CEC), and nutrient content, with TiO2/DGBC and Fe-TiO2/DGBC exhibiting better effects. ② DGBC and modified DGBCs transformed Cd from soluble to insoluble forms, increasing residual Cd by 1.22% to 18.46% compared to that in the control. Cd bioavailability in soil decreased significantly, with available cadmium being reduced by 11.81% to 23.67% for DGBC, 7.64% to 43.85% for TiO2/DGBC, and 19.75% to 55.82% for Fe-TiO2/DGBC. ③ DGBC and modified DGBCs increased rice grain yield, with the highest yields observed at a 3% application rate:30.60 g·pot-1 for DGBC, 37.85 g·pot-1 for TiO2/DGBC, and 39.10 g·pot-1 for Fe-TiO2/DGBC, representing 1.13, 1.40, and 1.44 times the control yield, respectively. Cd content in rice was significantly reduced, with grain Cd content ranging from 0.24 to 0.30 mg·kg-1 for DGBC, 0.16 to 0.26 mg·kg-1 for TiO2/DGBC, and 0.14 to 0.24 mg·kg-1 for Fe-TiO2/DGBC. Notably, Cd content in rice grains fell below the food safety limit of 0.2 mg·kg-1 (GB2762-2022) at 5% for TiO2/DGBC and 3% and 5% for Fe-TiO2/DGBC. In conclusion, Nano-TiO2 modified DGBC effectively reduced the bioavailability of soil Cd through its own adsorption and influence on soil Cd forms distribution, thus reducing the absorption of Cd by rice and simultaneously promoting rice growth and improving rice yield. It is a type of Cd-contaminated soil remediation material with a potential application prospect. The results can provide scientific basis for farmland restoration and agricultural safety production of Cd-contaminated acidic purple soil.

Assessing the impact of water-sediment factors on water quality to guide river-connected lake water environment improvement.

The substantial impacts of exogenous pollutants on lake water quality have been extensively reported. Water-sediment factors, which are essential for regulating water quality in river-connected lakes, have not been studied in depth under different hydrological conditions. This study has combined a 31-year water environmental dataset (1991-2021) regarding Dongting Lake and a vector autoregression model (VAR) in order to investigate the impulse response characteristics and contributions of water quality caused by water-sediment factors across different periods. Our analysis suggests that total nitrogen (TN) exhibited a significant increasing trend, whereas total phosphorus (TP) increased to 0.17 mg/L, and then decreased to 0.07 mg/L from 1991 to 2021. The inflow of suspended sediment discharge (SSD) decreased significantly during the study period, mainly because of the decrease in SSD in the three channels (TC). In the pre-Three Gorges Dam (TGD) period, water discharge (WD) and SSD were the Granger causes of TN and TP. In the post-TGD periods this relationship disappeared because of the construction of the TGD, which reduced the inflow of SSD and WD into the lake. Water quality indicators showed an instant response to the shock from themselves with high values, whereas the impulse response of the water quality to water-sediment factors exhibited lagged variations. This meant that the water quality indicators displayed a high impact by themselves across the different periods, with values varying from 67 % to 95 %. Water level (WL) and SSD were the predominant water-sediment factors for TP in the pre-TGD period, with the impact on TP changes accounting for 11 % and 9 %, respectively, whereas the contribution of SSD decreased to 2 % in the post-TGD period. WL was the most crucial water-sediment factor for CODMn during the different periods, with contributions varying from 17 % to 20 %. To improve the water quality of Dongting Lake, in addition to the implementation of strict controls on excessive external nutrient loading, regulating water-sediment factors according to the hydrological features of Dongting Lake during different periods is vital.