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A smartphone-enabled visual platform for detecting aflatoxins in peanut oil using colorimetric analysis coupled with magnetic imprinted solid-phase extraction
No full textThe study aimed to develop a rapid and sensitive colorimetric platform based on the Emerson reaction to visualize and determine total aflatoxins (AFs) in peanut oil. This method offers the advantage of fast screening for AFs (AFB1, AFB2, AFG1, and AFG2), eliminating the need for specific antibodies. The proposed approach combined colorimetric detection with magnetic dummy imprinted solid-phase extraction and purification, enhancing sensitivity and selectivity. The oxidizer aided the colorless AFs in reacting with 4-aminoantipyrine, producing green condensates. Thus, a dual-mode approach was developed for AFs detection, employing both UV-vis colorimetric and smartphone-based colorimetry. Both methods showed a good linear relationship with the concentration of AFs. Notably, the smartphone-based method demonstrated a detection range of 0.5-57 mu g/kg, with a detection limit as low as 0.21 mu g/kg. The suggested colorimetric methods present a promising potential for onsite detection and fast screening of AFs in actual samples
Dissolved N pollution and its biogeochemical constraints along a river-sea continuum of a typical dense oyster mariculture coastal water, northwest South China Sea
No full textDissolved nutrients, including nitrate (NO-3-N) and its dual isotopes (615N-NO- 3 and 618O-NO-3) were systematically studied along a river-sea continuum, wherein dense oyster mariculture is implemented, to constrain the pollution sources and biogeochemical cycling mechanisms of nitrogen (N). Total dissolved N, mainly composed of inorganic N, showed strong anthropogenic influence. Based on MixSIAR model results, N pollution was predominantly sourced from sewage/wastewater (55.9-64.3 %). Nutrient stoichiometry revealed DIP and DSi stress, and surface water in the riverine region was severely eutrophic. The occurrences of eutrophication and changes in nutrient stoichiometry were significantly related to N pollution sources in both summer and winter. N dynamics were controlled by anthropogenic activities and physical mixing. However, due to the insignificance of biological processes such as denitrification, phytoplankton assimilation, N2 fixation, and nitrification, including the lack of significant isotopic fractionation associated with these processes, and the poor fit of both the Rayleigh Model and Open system Model to the measured data, it is speculated that the several-fold reduction in N load and eutrophication along the river-sea continuum could be attributed to a combination of significant N removal by dense oyster mariculture and nutrient dilution due to physical mixing of river and seawater during winter and summer
H<sub>2</sub>S scavenger as a broad-spectrum strategy to deplete bacteria-derived H<sub>2</sub>S for antibacterial sensitization
No full textBacteria-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
Construction of a myoglobin scaffold-based biocatalyst for the biodegradation of sulfadiazine and sulfathiazole
No full textSulfonamide antibiotics, a family of broad-spectrum antibiotic drugs, are increasingly used in aquaculture and are frequently detected in aquatic environments. This poses a potential threat to organisms and may cause the evolution of antimicrobial resistance. Therefore, it is important to develop an environmentally friendly and efficient biocatalyst to degrade sulfonamides (SAs) such as sulfadiazine (SD) and sulfathiazole (ST). Here, we realized the direct and efficient degradation of SD and ST using a hydrogen peroxide-dependent artificial catalytic system based on myoglobin (Mb). The arrangements of amino acids at positions 29, 43, 64, and 68 were found to influence catalytic activity. An L29H/H64D/V68I myoglobin mutant showed the best catalytic efficiency (i.e., kcat/Km = 720.42 M-1 s-1) against SD. Next, mutant H64D/V68I showed the best degradation rate against SD (i.e., 91.45 +/- 0.16%). Moreover, L29H/H64D/V68I Mb was found to efficiently catalyze ST oxidatio
Nitrate transformation and source tracking of rivers draining into the Bohai Sea using a multi-tracer approach combined with an optimized Bayesian stable isotope mixing model
No full textExcessive levels of NO3 -can result in multiple eco-environmental issues due to potential toxicity, especially in coastal areas. Accurate source tracing is crucial for effective pollutant control and policy development. Bayesian models have been widely employed to trace NO3 -sources, while limited studies have utilized optimized Bayesian models for NO3 - tracing in the coastal rivers. The Bohai Rim is highly susceptible to ecological disturbances, particularly N pollution, and has emerged as a critical area. Therefore, identification the N fate and understanding their sources contribution is urgent for pollution mitigation efforts. In addition, understanding the influenced key driven factors to source dynamic in the past ten years is also implication to environmental management. In this study, water samples were collected from 36 major river estuaries that drain into the Bohai Sea of North China. The main transformation processes were analyzed and quantified the sources of NO3 -using a Bayesian stable isotope mixing model (MixSIAR) with isotopic approach (815N-NO3- and 818O-NO3-). The overall isotopic composition of 815N-NO3- and 818O-NO3- in estuary waters ranged from -0.8-19.3%o (9.3 +/- 4.6%o) and from -7.1-10.5%o (5.0 +/- 4.3%o), respectively. The main sources of nitrate in most river estuaries were manure & sewage, and chemical fertilizer, while weak denitrification and mixed processes were observed in Bohai Ri
Projections of land use/cover change and habitat quality in the model area of Yellow River delta by coupling land subsidence and sea level rise
No full textAccurately assessing future land use/cover change (LUCC) and habitat quality (HQ) is vital for ensuring sustainable use of coastal ecosystem services, but most studies ignore the effects of seawater inundation. This study developed a framework based on the PLUS model and InVEST-HQ model that considers seawater inundation due to sea level rise (SLR) and land subsidence. We used this framework to simulate future LUCC and HQ under different scenarios in the Yellow River Delta (YRD). The results showed: (1) From 1991 to 2020, natural wetlands decreased by 39.87 %, non-wetlands decreased by 3.06 %, and artificial wetlands increased by 730.71 %. The overall HQ showed a decreasing trend, with the largest decrease in non-wetlands. (2) Land subsidence occurred in 93.26 % of the YRD, with a subsidence rate of-36.55 mm/year. Underground brine mining is the most important driving factor. About 6.81 %-11.16 % of the area will be inundated in 2035, and about 9.39 %-19.27 % of the area will be inundated in 2050. (3) Future multi-scenario simulations show that the Ecological-Protection scenario can minimize the ecological losses caused by seawater inundation. The simulation of future HQ will be underestimated when seawater inundation is not considered. Our study shows that seawater inundation caused by land subsidence and SLR must be taken into account when simulating LUCC and HQ in coastal areas
Long-Term Fertilization Contributes to Carbon Saturation in Neutral-To-Alkaline Soils but not in Acidic Soils
No full textThe study investigated the adsorption of dissolved organic carbon (DOC) on Chinese soils from four long-term experiments involving five treatments: (1) no fertilization (control), (2-4) inorganic nitrogen (N), phosphorus (P), and potassium (K) fertilization (N, NP, and NPK), (5) NPK plus manure (NPKM). The results showed that DOC adsorption followed a modified Langmuir isotherm model effectively (R-2 = 0.912 similar to 0.991). The maximum adsorption capacity (Q(max)) (i.e. saturation deficits) generally increased with increasing soil organic carbon (SOC) due to fertilization in Luvic Phaeozem, Haplic Gypsisols, and Eutric Cambisols. However, it decreased significantly in acidic soils (Haplic Acrisols) from 15.59 g/kg for control, to 13.96, 13.03, 9.30 and 8.02 g/kg for N, NP, NPK and NPKM, respectively. Moreover, long-term fertilization, particularly with organic fertilization (e.g. NPKM), resulted in an increase of carbon (C) saturation by 1.42 g/kg (5.52%) in Luvic Phaeozem, 9.27 g/kg (44.29%) in Haplic Gypsisols, and 3.75 g/kg (27.66%) in Eutric Cambisols; however, there was a slight decrease by 1.70 g/kg (-7.49%) in Haplic Acrisols. Canonical correlation analysis (CCA) revealed that clay content and soil available iron (AFe) might be the crucial factors controlling C deficits, and subsequently, C saturation, along with current SOC. In conclusion, long-term fertilization contributed to C saturation in neutral-to-alkaline soils, but not in acidic soils. Thus, further attention should be paid to the long-term effects of fertilization on C saturation
Compound extreme inundation risk of coastal wetlands caused by climate change and anthropogenic activities in the Yellow River Delta, China
No full textThe coastal wetlands of the Yellow River Delta (YRD) in China are crucial for their valuable resources, environmental significance, and
economic contributions. However, these wetlands are also vulnerable to the dual threats of climate change and human disturbances. Despite
substantial attention to the historical shifts in YRD's coastal wetlands, uncertainties remain regarding their future trajectory in the face of
compound risks from climate change and anthropogenic activities. Based on a range of remote sensing data sources, this study undertakes a
comprehensive investigation into the evolution of YRD's coastal wetlands between 2000 and 2020. Subsequently, the potential fate of coastal
wetlands is thoroughly analyzed through the Land Use/Cover Change (LUCC) simulation using System Dynamic-Future Land Use Simulation
(SD-FLUS) model and the extreme water levels projection integrated future sea-level rise, storm surge, and astronomical high tide in 2030, 2050,
and 2100 under scenarios of SSP1-2.6, SSP2-4.5, and SSP5-8.5. Results revealed that YRD's coastal wetlands underwent a marked reduction,
shrinking by 1688.72 km2 from 2000 to 2020. This decline was mostly attributed to the substantial expansion in the areas of artificial wetlands
(increasing by 823.78 km2), construction land (increasing by 767.71 km2), and shallow water (increasing by 274.58 km2). Looking ahead to
2030e2100, the fate of coastal wetlands appears to diverge based on different scenarios. Under the SSP1-2.6 scenario, the area of coastal
wetland is projected to experience considerable growth. In contrast, the SSP5-8.5 scenario anticipates a notable decrease in coastal wetlands.
Relative to the inundated area suffered from the current extreme water levels, the study projects a decrease of 6.8%e10.6% in submerged coastal
wetlands by 2030 and 9.4%e18.2% by 2050 across all scenarios. In 2100, these percentages are projected to decrease by 0.4 % (SSP2-4.5) and
27.1% (SSP5-8.5), but increase by 35.7% (SSP1-2.6). Results suggest that coastal wetlands in the YRD will face a serious compound risk from
climate change and intensified human activities in the future, with climate change being the dominant factor. More efficient and forward-looking
measures must be implemented to prioritize the conservation and management of coastal wetland ecosystems to address the challenges,
especially those posed by climate change
Rapid antibiotic screening based on E. coli apoptosis using a potentiometric sensor array
No full textPhenotypic antimicrobial susceptibility testing enables reliable antibiotic screening but requires multiple strategies to identify each phenotypic change induced by different bactericidal mechanisms. Bacteria apoptosis with typical phenotypic features has never been explored for antibiotic screening. Herein, we developed an antibiotic screening method based on the measurement of antibiotic-induced phosphatidylserine (PS) exposure of apoptotic bacteria. Phosphatidylserine externalization of E. coli that can be widely used as an apoptosis marker for antibiotics with different antibacterial mechanisms was explored. A positively charged PS-binding peptide was immobilized on magnetic beads (MBs) to recognize and capture apoptotic E. coli with PS externalization. Apoptotic E. coli binding led to the charge or charge density change of MBs-peptide, resulting in a potential change on a magneto-controlled polymeric membrane potentiometric sensor. Based on the detection of apoptotic E. coli killed by antibiotics, antibiotic screening for different classes of antibiotics and silver nanoparticles was achieved within 1.5 h using a potentiometric sensor array. This approach enables sensitive, general, and timesaving antibiotic screening, and may open up a new path for antibiotic susceptibility testing
The pollution characteristics and risk assessment of microplastics in mollusks collected from the Bohai Sea
No full textMicroplastics (MPs) pollution in the marine environment has become a global problem. In this study, a number of 21 mollusk species (n = 2006) with different feeding habits were collected from 11 sites along the Bohai Sea for MPs uptake analysis. The MPs in mollusk samples were isolated and identified by micro-Fourier Transform Infrared Spectroscopy (mu-FTIR), and an assessment of the health risks of MPs ingested by mollusk consumption is also conducted. Approximately 91.9 % of the individuals among all the collected species inhaled MPs, and there was an average abundance of 3.30 +/- 2.04 items & sdot;individual- 1 or 1.04 +/- 0.74 items & sdot;g- 1 of wet weight. The shape of MPs was mainly fiber, and a total number of 8 polymers were detected, of which rayon had the highest detection rate (58.3 %). The highest abundance, uptake rate and polymer composition of MPs was observed in creeping types, suggesting that they might ingest these MPs from their food. The gastropod Siphonalia subdilatata contains the highest levels of MPs, which may increase the risk of human exposure if consumed whole without removing the digestive gland. The polymer risk level of MPs in these mollusks was Level III (H = 299), presenting harmful MPs such as polyvinyl chloride. In terms of human exposure risk, the average risk of human exposure to MPs through consumption of Bohai mollusks is estimated to be 3399 items & sdot;(capita & sdot;year)-1 (424-9349 items & sdot; (capita & sdot;year)-1). Overall, this study provides a basis for the ecological and health Risk assessment of MPs in mollusks collected from the coastline of China