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Tidal Flat Extraction and Analysis in China Based on Multi-Source Remote Sensing Image Collection and MSIC-OA Algorithm
Tidal flats, a critical part of coastal wetlands, offer unique ecosystem services and functions. However, in China, these areas are under significant threat from industrialization, urbanization, aquaculture expansion, and coastline reconstruction. There is an urgent need for macroscopic, accurate and periodic tidal flat resource data to support the scientific management and development of coastal resources. At present, the lack of macroscopic, accurate and periodic high-resolution tidal flat maps in China greatly limits the spatio-temporal analysis of the dynamic changes of tidal flats in China, and is insufficient to support practical management efforts. In this study, we used the Google Earth Engine (GEE) platform to construct multi-source intensive time series remote sensing image collection from Sentinel-2 (MSI), Landsat 8 (OLI) and Landsat 9 (OLI-2) images, and then automated the execution of improved MSIC-OA (Maximum Spectral Index Composite and Otsu Algorithm) to process the collection, and then extracted and analyzed the tidal flat data of China in 2018 and 2023. The results are as follows: (1) the overall classification accuracy of the tidal flat in 2023 is 95.19%, with an F1 score of 0.92. In 2018, these values are 92.77% and 0.88, respectively. (2) The total tidal flat area in 2018 and 2023 is 8300.34 km2 and 8151.54 km2, respectively, showing a decrease of 148.80 km2. (3) In 2023, estuarine and bay tidal flats account for 54.88% of the total area, with most tidal flats distribute near river inlets and bays. (4) In 2023, the total length of the coastline adjacent to the tidal flat is 10,196.17 km, of which the artificial shoreline accounts for 67.06%. The development degree of the tidal flat is 2.04, indicating that the majority of tidal flats have been developed and utilized. The results can provide a valuable data reference for the protection and scientific planning of tidal flat resources in China
Reclamation of co-pyrolyzed dredging sediment as soil cadmium and arsenic immobilization material: Immobilization efficiency, application safety, and underlying mechanisms
The safe management of toxic metal-polluted dredging sediment (DS) is imperative owing to its potential secondary hazards. Herein, the co-pyrolysis product (DS@BC) of polluted DS was creatively applied to immobilize soil Cd and As to achieve DS resource utilization, and the efficiency, safety, and mechanism were investigated. The results revealed that the DS@BC was more effective at reducing soil Cd bioavailability than the DS was (58.9-73.2% vs. 21.8-27.4%), except for the dilution effect, whereas the opposite phenomenon occurred for soil As (25.5-35.7% vs. 35.7-42.8%). The DS@BC immobilization efficiency was dose-dependent for both Cd and As. Soil labile Cd and As were transformed to more stable fractions after DS@BC immobilization. DS@BC immobilization inhibited the transfer of soil Cd and As to Brassica chinensis L. and did not cause excessive accumulation of other toxic metals in the plants. The appropriate addition of the DS@BC (8%) sufficiently alleviated the oxidative stress response of the plants and enhanced their growth. These findings indicate that the DS@BC was safe and effective for soil Cd and As immobilization. DS@BC immobilization decreased the diversity and richness of the rhizosphere soil bacterial community because of the dilution effect. The DS@BC immobilized soil Cd and As via direct adsorption, and indirect increasing soil pH, and regulating the abundance of specific beneficial bacteria (e.g., Bacillus). Therefore, the use of co-pyrolyzed DS as a soil Cd and As immobilization material is a promising resource utilization method for DS. Notably, to verify the long-term effects and safety of DS@BC immobilization, field trials should be conducted to explore the effectiveness and risk of harmful metal release from DS@BC immobilization under real-world conditions
Reclamation of co-pyrolyzed dredging sediment as soil cadmium and arsenic immobilization material: Immobilization efficiency, application safety, and underlying mechanisms
The safe management of toxic metal-polluted dredging sediment (DS) is imperative owing to its potential secondary hazards. Herein, the co-pyrolysis product (DS@BC) of polluted DS was creatively applied to immobilize soil Cd and As to achieve DS resource utilization, and the efficiency, safety, and mechanism were investigated. The results revealed that the DS@BC was more effective at reducing soil Cd bioavailability than the DS was (58.9-73.2% vs. 21.8-27.4%), except for the dilution effect, whereas the opposite phenomenon occurred for soil As (25.5-35.7% vs. 35.7-42.8%). The DS@BC immobilization efficiency was dose-dependent for both Cd and As. Soil labile Cd and As were transformed to more stable fractions after DS@BC immobilization. DS@BC immobilization inhibited the transfer of soil Cd and As to Brassica chinensis L. and did not cause excessive accumulation of other toxic metals in the plants. The appropriate addition of the DS@BC (8%) sufficiently alleviated the oxidative stress response of the plants and enhanced their growth. These findings indicate that the DS@BC was safe and effective for soil Cd and As immobilization. DS@BC immobilization decreased the diversity and richness of the rhizosphere soil bacterial community because of the dilution effect. The DS@BC immobilized soil Cd and As via direct adsorption, and indirect increasing soil pH, and regulating the abundance of specific beneficial bacteria (e.g., Bacillus). Therefore, the use of co-pyrolyzed DS as a soil Cd and As immobilization material is a promising resource utilization method for DS. Notably, to verify the long-term effects and safety of DS@BC immobilization, field trials should be conducted to explore the effectiveness and risk of harmful metal release from DS@BC immobilization under real-world conditions
G-Quadruplex Dimer/Exonuclease I Assisted Signal Amplification Strategy for Rapid Determination of Aflatoxin B1 Using a Paper Chip
In this work, a tetrahedral DNA nanostructure (TDN) functionalized rotational paper-based analytical device (RPAD) was constructed for rapid and highly sensitive detection of aflatoxin B1 (AFB1) using exonuclease I (Exo I ) and G-quadruplex (G4) dimer. Herein, a single-stranded DNA, containing both of the G4 dimer sequence and AFB1 recognition sequence, was used as the recognition probe (G4 dimer probe). TDN was used to precisely regulate the orientation and distribution density of G4 dimer probe to improve the recognition efficiency of the system. Exo I as a single stranded DNA specific nuclease was introduced for effective amplification of the detection signal. G4 dimer was employed to enhance the fluorescence signal of thioflavin T (ThT). In the absence of AFB1, the G4 dimer structure of G4 dimer probe could specifically bind with ThT to generate dramatic fluorescence enhancement. However, in the presence of AFB1, AFB1 could specifically bind with G4 dimer probe, resulting in the dissociation of G4 dimer probe from TDN and further be digested by Exo I . At the same time, the released AFB1 could bind to G4 dimer probe on the TDN again by this way to generate signal amplification. After this cycle, the amount of aptamer on the TDN was decreased, accompanied by the reduction of G4 dimer on TDN. In this case, the fluorescence intensity of the system was reduced. The designed RPAD showed a good linear response in AFB1 concentration range of 0.0001-500 ng/mL and the limit of detection was 0.1 pg/mL. Moreover, the proposed strategy was successfully applied to detection of AFB1 in peanut and wine. The developed TDN/G4 dimer/Exo I strategy improved the specificity and sensitivity of the system significantly
Detrimental effects of glyphosate on muscle metabolism in grass carp (<i> Ctenopharyngodon</i> idellus)
Glyphosate, a commonly used herbicide, has been associated with environmental pollution and potential health risks to aquatic organisms. This study investigated the effects of glyphosate on the muscle metabolism of grass carp (Ctenopharyngodon idellus) following exposure to environmentally relevant concentrations. Over a 14-day exposure period to varying glyphosate levels, significant disruptions were observed in antioxidant capacity and muscle health. These disruptions were evidenced by reductions in total antioxidant capacity (T-AOC), increases in malondialdehyde (MDA) levels, and decreases in activities of glutathione peroxidase (GSH-PX) and catalase (CAT). Furthermore, exposure to glyphosate resulted in a reduction of vitamin E content and an elevation of hormonal levels, suggesting the potential for endocrine disruption. Metabolomics analysis identified 605 distinct metabolites, with notable alterations in amino acid, carbohydrate, and nucleotide metabolism pathways. Specifically, arginine and glutathione metabolisms were severely impacted, with decreases in key amino acids such as glycine and glutathione at higher glyphosate concentrations. Nucleotide metabolism, particularly purine synthesis, was also significantly affected, with reduced levels of deoxyguanosine and other purine-related compounds. The study further investigated the origins of these differential metabolites using the MetOrigin platform, suggesting a potential involvement of the intestinal microbiota in the metabolic response to glyphosate. These findings highlight the multifaceted adverse effects of glyphosate on fish muscle, including oxidative stress and metabolic dysregulation, which may contribute to diminished muscle quality and health risks for aquatic organisms
Detrimental effects of glyphosate on muscle metabolism in grass carp (<i> Ctenopharyngodon</i> idellus)
Glyphosate, a commonly used herbicide, has been associated with environmental pollution and potential health risks to aquatic organisms. This study investigated the effects of glyphosate on the muscle metabolism of grass carp (Ctenopharyngodon idellus) following exposure to environmentally relevant concentrations. Over a 14-day exposure period to varying glyphosate levels, significant disruptions were observed in antioxidant capacity and muscle health. These disruptions were evidenced by reductions in total antioxidant capacity (T-AOC), increases in malondialdehyde (MDA) levels, and decreases in activities of glutathione peroxidase (GSH-PX) and catalase (CAT). Furthermore, exposure to glyphosate resulted in a reduction of vitamin E content and an elevation of hormonal levels, suggesting the potential for endocrine disruption. Metabolomics analysis identified 605 distinct metabolites, with notable alterations in amino acid, carbohydrate, and nucleotide metabolism pathways. Specifically, arginine and glutathione metabolisms were severely impacted, with decreases in key amino acids such as glycine and glutathione at higher glyphosate concentrations. Nucleotide metabolism, particularly purine synthesis, was also significantly affected, with reduced levels of deoxyguanosine and other purine-related compounds. The study further investigated the origins of these differential metabolites using the MetOrigin platform, suggesting a potential involvement of the intestinal microbiota in the metabolic response to glyphosate. These findings highlight the multifaceted adverse effects of glyphosate on fish muscle, including oxidative stress and metabolic dysregulation, which may contribute to diminished muscle quality and health risks for aquatic organisms
Synchrotron Radiation: A Key Tool for Drug Discovery
Synchrotron radiation is extensively utilized in the domains of materials science, physical chemistry, and life science, resulting from its high intensity, exceptional monochromaticity, superior collimation, and broad wave spectrum. This top-notch light source has also made significant contributions to the progress of biomedicine. The advancement of synchrotron radiation-based X-ray and protein crystallography technologies has created new prospects for drug discovery. These innovative techniques have opened up exciting avenues in the field. The investigation of protein crystal structures and the elucidation of the spatial configuration of biological macromolecules have revealed intricate details regarding the modes of protein binding. Furthermore, the screening of crystal polymorphs and ligands has laid the groundwork for rational drug modification and the improvement of drug physicochemical properties. As science and technology continue to advance, the techniques for analyzing structures using synchrotron radiation sources and the design of corresponding crystallographic beamline stations are undergoing continuous enhancement. These cutting-edge tools and facilities are expected to expedite the drug development process and rectify the current situation of a lack of targeted drugs
Artificial river flow regulation triggered spatio-temporal changes in marine macrobenthos of the Yellow River Estuary
The Water Sediment Discharge Regulation (WSR) in the Yellow River transports a vast quantity of freshwater and materials to the Bohai Sea within 20 days, significantly altering the ambient environment of the estuary. To elucidate the ecological impacts of this typically artificial flood event, we investigated the benthic habitats and macrobenthic biodiversity within the Affected Core Area (ACA) influenced by this discharge. Our results show that: (1) The discharge created an area with extreme environmental conditions, extending from the southern estuary to Laizhou Bay. This led to a rapid transformation of the habitat, as evidenced by a significant increase in turbidity, ammonium, and silicate levels. Among these factors, nitrogen nutrients and pH were the dominant drivers of environmental filtration, shaping the macrobenthos community structure; (2) The changing habitat triggered spatial shifts in macrobenthos abundance based on the distance from the estuary. Compared to the northern estuary, species composition and C-diversity in the southern area decreased significantly. These changes collectively established a short-term biodiversity front in the estuary region; (3) Community stability declined, as evidenced by a 24.20% reduction in niche width for generalist species and a 90.91% shift in specialist species. Furthermore, the connectivity between species decreased, and the average path length of the network increased, resulting in a more fragmented community structure. Notably, some ecological patches dominated by generalist species (e.g. Alpheus distinguendus) emerged. These findings enhance our understanding of marine ecological responses to artificial flood events within the context of global environmental changes
Stopover habitat use of coastal Pied Avocet revealed by satellite tracking and remote sensing technology
Stopover sites identification for migratory waterbirds is important in China's coastal wetlands, which have experienced a massive loss of natural wetlands in recent decades. Taking the Pied Avocet (Recurvirostra avosetta), a common waterbird in China's coastal zone as an example, our research focused on their stopover habitat use based on satellite tracking and remote sensing technology. Along the coast, a total of 6 critical stopover sites, duration of stay more than 14 days, were recognized during their 2022-2023 autumn and spring migrations of the 4 tagged individuals. The results showed that Pied Avocets used habitats close to the coastline and water source, at low elevation, and with sparse vegetation. They also had a certain tolerance for human interference. From the perspective of the land use and land cover type, the proportion (33.01 %) of artificial wetlands including paddy, salt pan, and mariculture has exceeded that (27.97 %) of natural wetlands such as bottomland, tidal flat, estuarine waters, and shallow water in the home ranges of the 6 stopover areas. The study emphasized that the habitat function of artificial wetland should be paid enough attention to while maintaining the natural wetland without further loss. In addition, habitat-oriented management suggestions were put forward for artificial wetlands. This study can provide data and technical support for the conservation and management of waterbirds stopovers, also having reference value for other species
H<sub>2</sub>S scavenger as a broad-spectrum strategy to deplete bacteria-derived H<sub>2</sub>S for antibacterial sensitization
Bacteria-derived H2S plays multifunctional protective roles against antibiotics insult, and the H2S biogenesis pathway is emerging as a viable target for the antibacterial adjuvant design. However, the development of a pan-inhibitor against H2S-synthesizing enzymes is challenging and underdeveloped. Herein, we propose an alternative strategy to downregulate the H2S levels in H2S-producing bacteria, which depletes the bacteria-derived H2S chemically by H2S scavengers without acting on the synthesizing enzymes. After the screening of chemically diversified scaffolds and a structural optimization campaign, a potent and specific H2S scavenger is successfully identified, which displays efficient H2S depletion in several H2S-producing bacteria, potentiates both bactericidal agents and photodynamic therapy, enhances the bacterial clearance of macrophages and polymorphonuclear neutrophils, disrupts the formation of bacterial biofilm and increases the sensitivity of bacterial persister cells to antibiotics. Most importantly, such an H2S scavenger exhibits sensitizing effects with gentamicin in Pseudomonas aeruginosa -infected pneumonia and skin wound female mouse models. In aggregate, our results not only provide an effective strategy to deplete bacteria-derived H2S and establish the H2S biogenesis pathway as a viable target for persisters and drug-resistant bacteria, but also deliver a promising antibacterial adjuvant for potential clinical translation.
Bacteria-derived H2S functions as a universal defense against antibiotics challenge. Here, Ji et al developed a broad-spectrum H2S scavenger that efficiently removes endogenous H2S in several bacteria, disrupts biofilm formation and sensitizes persister cells to antibiotic-mediated killing in vitro and in vivo