Integrative approach to mitigate chromium toxicity in soil and enhance antioxidant activities in rice (Oryza sativa L.) using magnesium-iron nanocomposite and Staphylococcus aureus strains.

Pollutants in soil, particularly chromium (Cr), pose high environmental and health risks due to their persistence, bioavailability, and potential for causing toxicity. Cr impairment in plants act as a deleterious environmental pollutant that enters the food chain and eventually disturbs human health. Current study demonstrated the potential of integrative foliar application of magnesium-iron (Mg + Fe) nanocomposite with Staphylococcus aureus strains to alleviate Cr toxicity in rice (Oryza sativa) crops by improving yield and defense system. Growth and yield traits such as shoot length (15%), root length (17%), shoot fresh weight (14%), shoot dry weight (9%), root fresh weight (23%), root dry weight (7%), number of tillers (33%), number of grains (10%) and spike length (13%) improved by combined application of Mg + Fe (20 mg L-1) nanocomposite and S. aureus strains with Cr (110 mg kg-1), compared to when applied alone. Mutual Mg + Fe and S. aureus strains application augmented the SPAD value (9%), total chlorophyll (11%), a (12%), b (17%), and carotenoids (32%), with Cr (110 mg kg-1), compared to alone. Malondialdehyde (13%), hydrogen peroxide (H2O2) (11%), and electrolyte leakage (7%) were significantly regulated in shoots with combined Mg + Fe and S. aureus strains application with Cr (110 mg kg-1) contrasted to alone. Peroxidase (20%), superoxide dismutase (17%), ascorbate peroxidase (18%), and catalase (20%) were increased in shoots with combined Mg + Fe and S. aureus strains application with Cr (110 mg kg-1) in comparison to alone. The combined application of Mg + Fe (20 mgL-1) nanocomposite and S. aureus strains with Cr (110 mg kg-1) enhanced the macro-micronutrients in shoots compared to alone. Cr accumulation in roots (21%), shoots (25%), and grains (47%) were significantly reduced under Cr (110 mg kg-1) with combined Mg + Fe and S. aureus strains application, compared to alone. Subsequently, applying combined Mg + Fe and S. aureus strains is a sustainable solution to boost crop production under Cr toxicity.

Trade-off between sulfidated zero-valent iron reactivity and air stability: Regulation of iron sulfides by ammonium dihydrogen phosphate.

The reactivity and stability of zero-valent iron (ZVI) and sulfidated zero-valent iron (S-ZVI) are inherently contradictory. Iron sulfides (FeSX) on the S-ZVI surface play multiple roles, including electrostatic adsorption and catalyzing reduction. We proposed to balance the reactivity and air stability of S-ZVI by regulating FeSX. Benefiting from the superior coordination and accelerate electron transport capabilities of phosphate, herein, eco-friendly ammonium dihydrogen phosphate (ADP) was employed to synthesize N, P, and S-incorporated ZVI (NPS-ZVI) and regulate the FeSX. Raman, FTIR, XPS, and density functional theory (DFT) calculations were combined to reveal that HPO42- acts as the main P species on the Fe surface. The superior reactivity of NPS-ZVI was quantified by kobs, kSA, and kM of Cr(VI), which were 210.77, 27.44, and 211.17-fold than ZVI, respectively. NPS-ZVI demonstrated excellent reusability, with no risk of secondary pollution. Critically, NPS-ZVI could effectively maintain FeSX stability under the combination of diffusion limitation and surface protection mechanisms of ADP. The superior reactivity of NPS-ZVI was attributed to the fact that ADP maintains FeSX stability and accelerates electron transport. This study provides a novel strategy in balancing the reactivity and air stability of S-ZVI and offers theoretical support for material modification.

Decoding the divalent cation effect on sulfidation of zero-valent iron: Phase evolution and FeSx assembly.

The decontamination ability of sulfidated zero-valent iron (S-ZVI) can be enhanced by the effective assembly of iron sulfides (FeSx) on neglected heterogeneous surfaces by liquid-phase precipitation. However, S-ZVI preparation with the usual pickling is detrimental to orderly interfacial assembly and leads to an imbalance between electron transfer optimization and electron storage. In this work, S-ZVI was prepared in solutions containing trace divalent cation, and it removed Cr(VI) up to 323.25 times higher than ZVI. This result is achieved by surface sites protonation of divalent cations regulating the phase evolution on the ZVI surface and inducing FeSx chemical assembly. Regulation of divalent cation and S(-II) content further promotes FeSx targeted assembly and reduces electron storage consumption as much as possible. The barrier for FeSx assembly is found to lie at the ZVI interface rather than in the deposition between FeSx. Chemical assembly at heterogeneous interfaces is a prerequisite for the ordered assembly of FeSx. In addition, S-ZVI prepared in simulated groundwater showed extensive preparation pH and universality for remediation scenarios. These findings provide new insights into the development of in-situ sulfidation mechanisms with particular implications for S-ZVI applied to soil and groundwater remediation by the regulation of heterogeneous interfacial assembly.

Performance and mechanism of SMX removal by an electrolysis-integrated ecological floating bed at low temperatures: A new perspective of plant activity, iron plaque, and microbial functions.

Improvements in plant activity and functional microbial communities are important to ensure the stability and efficiency of pollutant removal measures in cold regions. Although electrochemistry is known to accelerate pollutant degradation, cold stress acclimation of plants and the stability and activity of plant-microbial synergism remain poorly understood. The sulfamethoxazole (SMX) removal, iron plaque morphology, plant activity, microbial community, and function responses were investigated in an electrolysis-integrated ecological floating bed (EFB) at 6 ± 2 â„ƒ. Electrochemistry significantly improved SMX removal and plant activity. Dense and uniform iron plaque was found on root surfaces in L-E-Fe which improved the plant adaptability at low temperatures and provided more adsorption sites for bacteria. The microbial community structure was optimized and the key functional bacteria for SMX degradation (e.g., Actinobacteriota, Pseudomonas) were enriched. Electrochemistry improves the relative abundance of enzymes related to energy metabolism, thereby increasing energy responses to SMX and low temperatures. Notably, electrochemistry improved the expression of target genes (sadB and sadC, especially sadC) involved in SMX degradation. Electrochemistry enhances hydrogen bonding and electrostatic interactions between SMX and sadC, thereby enhancing SMX degradation and transformation. This study provides a deeper understanding of the electrochemical stability of antibiotic degradation at low temperatures.

[Photodegradation of Plastic Blends in Seawater and Its Risk to the Marine Environment].

The production and use of plastic blends have been gradually increasing owing to their versatility and low cost. However, the photodegradation of plastic blends in seawater and the potential risk to the marine environment are still not well understood. In this study, plastic blends including polypropylene/thermoplastic starch blends(PP/TPS) and polylactic acid/poly(butylene adipate-co-terephthalate)/thermoplastic starch blends(PLA/PBAT/TPS) were investigated. The corresponding neat polymers, namely polypropylene(PP) and polylactic acid(PLA), were set as control groups. We investigated the formation of MPs and the changes in the physicochemical properties of plastic blends after photodegradation in seawater. The size distribution of MPs indicated that PP/TPS and PLA/PBAT/TPS were more likely to produce small-sized particles after photodegradation than PP and PLA owing to their poorer mechanical properties and lower resistance to UV irradiation. Noticeable surface morphology alterations, including cracks and wrinkles, were observed for plastic blends following photodegradation, whereas PP and PLA were relatively resistant. After photodegradation, the ATR-FTIR spectrum of PP/TPS and PLA/PBAT/TPS showed a significant decrease in the characteristic bands of thermoplastic starch(TPS), indicating the degradation of their starch fractions. The C 1s spectra demonstrated that aged plastic blends contained fewer -OH groups than the pristine MPs did, further confirming the photodegradation of TPS. These results indicate that PP/TPS and PLA/PBAT/TPS had a higher degree of photodegradation than PP and PLA and thereby generated more small-sized MPs. In summary, plastic blends may pose a higher risk to the marine environment than neat polymers, and caution should be taken in the production and use of plastic blends.

Optimum fertilizer application rate to ensure yield and decrease greenhouse gas emissions in rain-fed agriculture system of the Loess Plateau.

Application of nitrogen (N) can increase the supply of N in soil and, in turn, can lead to higher yield-but also to large increase in emissions of greenhouse gases (GHGs) if applied in excess. To determine the optimum dose of N for maize planting system, we analysed the relationship between yield and emissions of GHGs at seven levels of N, namely 50, 100, 150, 200, 250, 300, and 350 kg ha-1, using the DNDC (denitrification decomposition) model and maize grown with and without mulching. The model simulated the following variables: maize production; emissions of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4); global warming potential (GWP); and GHG intensity (GHGI). We used data from 1980 to 2013 for a rain-fed region of the Loess Plateau in north-western China and validated the DNDC model against data from field experiments. The model performed well in simulating yield and GHG emissions (Adj.R2 > 0.61). Under mulching, the average yield of maize was 3.6-12.2 t ha-1 and the partial factor productivity was 73.1-35.0 kg kg-1; and both of these were significantly higher 78%-236% than those in the crop without mulching. The emissions of CO2, N2O, and the GWP increased with the increase in the dose of N whereas CH4 emissions remained unaffected by the dose. Mulching increased yields significantly in the north-western region, and the GWP and GHGI were higher mainly in the central and north-western regions. The optimum dose of N for maize grown with mulching ranged between 150 kg ha-1 and 200 kg ha-1 and offers the best balance between higher yield and lower emissions. The optimum dose may promote the development of mulched maize and provide a reference standard for dryland agriculture in zones with similar climates elsewhere in the world.

Phase evolution of the surface iron (hydr)oxides to the iron sulfide through anion exchange during sulfidation of zero valent iron.

The naturally-formed iron (hydr)oxides on the surface of zero valent iron (ZVI) have long been considered as passivation layer and inert phases which significantly reduce the reaction activities when they are employed in environmental remediation. Although it seems there are no direct benefits to keep these passivation layers, here, we show that such phases are necessary intermediates for the transformation to iron sulfides through an anion exchange pathway during sulfidation of ZVI. The pre-formed (hydr)oxides undergo a phase evolution upon aging and specific phases can be effectively trapped, which can be confirmed by a combination of different characterization techniques including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRPD), and X-ray absorption near edge structure (XANES) spectroscopy. Interestingly, after sulfidation, the resultant samples originated from different (hydr)oxides demonstrate different activities in the Cr(VI) sequestration. The XANES investigation of Fe K edge and Fe L2,3 edge indicates Fe remains the same after sulfidation, suggesting a non-redox, anion exchange reaction pathway for the production of iron sulfides, where O2- anions are directly replaced with S2-. Consequently, the structural characteristics of the parent (hydr)oxides are inherited by the as-formed iron sulfides, which make them behave differently because of their different structural natures.

Optimum plastic mulching application to reduce greenhouse gas emissions without compromising on crop yield and farmers' income.

With the rapid socio-economic development in China, poverty alleviation and the reduction of the environmental footprint in the plastic film mulching (PM) planting system have become key to sustainable agricultural production. Although many studies have evaluated the maize yield, agricultural economic benefits, and greenhouse gas (GHG) emissions associated with PM through small-scale field experiments, identifying suitable PM regions in combination with their demographic characteristics and the future development of such systems has received little attention. This study combines a Denitrification-Decomposition (DNDC) model and demographic characteristics to determine the optimum PM region in rainfed areas of the Loess Plateau in northwest China. The results demonstrated that PM produced a higher maize yield, agricultural net profit (ANP), and cost-benefit ratio compared to a control treatment (CK) without PM. An agricultural income far above the poverty level would assist in meeting the goals of alleviating poverty and building a prosperous society. In addition, the PM system produced more GHG emissions, but had a lower greenhouse gas intensity (GHGI) than CK under both low (200 kg N ha-1) and high (300 kg N ha-1) nitrogen (N) fertilizer rates. This study developed a framework to evaluate maize yield alongside economic and environmental indicators. We concluded that PM should be adopted in areas with precipitation less than 500 mm, and concentrated in the region with rainfall of 200-400 mm. The results provide a theoretical basis for the sustainable development of the PM maize planting system, and will contribute to the desired goal of environmentally sustainable agricultural production.

Mitochondrial dysfunction in mouse livers depleted of iron chaperone PCBP1.

Iron is an essential nutrient that forms cofactors required for the activity of hundreds of cellular proteins. However, iron can be toxic and must be precisely managed. Poly r(C) binding protein 1 (PCBP1) is an essential, multifunctional protein that binds both iron and nucleic acids, regulating the fate of both. As an iron chaperone, PCBP1 binds cytosolic iron and delivers it to iron enzymes for activation and to ferritin for storage. Mice deleted for PCBP1 in the liver exhibit dysregulated iron balance, with lower levels of liver iron stores and iron enzymes, but higher levels of chemically-reactive iron. Unchaperoned iron triggers the formation of reactive oxygen species, leading to lipid peroxidation and ferroptotic cell death. Hepatic PCBP1 deletion produces chronic liver disease in mice, with steatosis, triglyceride accumulation, and elevated plasma ALT levels. Human and mouse models of fatty liver disease are associated with mitochondrial dysfunction. Here we show that, although deletion of PCBP1 does not affect mitochondrial iron balance, it does affect mitochondrial function. PCBP1 deletion affected mitochondrial morphology and reduced levels of respiratory complexes II and IV, oxygen consumption, and ATP production. Depletion of mitochondrial lipids cardiolipin and coenzyme Q, along with reduction of mitochondrial oxygen consumption, were the first manifestations of mitochondrial dysfunction. Although dietary supplementation with vitamin E ameliorated the liver disease in mice with hepatic PCBP1 deletion, supplementation with coenzyme Q was required to fully restore mitochondrial lipids and function. In conclusion, our studies indicate that mitochondrial function can be restored in livers subjected to ongoing oxidative damage from unchaperoned iron by supplementation with coenzyme Q, a mitochondrial lipid essential for respiration that also functions as a lipophilic radical-trapping agent.

Effect of plastic film mulching and film residues on phthalate esters concentrations in soil and plants, and its risk assessment.

The application of plastic film mulching can greatly improve dryland productivity, while the release of toxic phthalate esters (PAEs) from the plastic film has generated concern. This study investigated the effects of mulched plastic film and residual plastic film on the PAE concentrations in the soil-crop system and assessed the risks to people eating crop products. The PAEs concentration in the 0-25 cm soil layer of plastic mulched farmland was 0.45-0.81 mg/kg, while the average PAEs concentration of 0.37-0.73 mg/kg in non-mulched farmland decreased by 19%. The PAEs concentration in mulched soil reached the highest in July, being 0.80-0.84 mg/kg, while in the non-mulched soil, the PAEs also appeared and gradually decreased from May at 0.62-0.74 mg/kg to October, and the PAEs concentrations were almost the same in the mulched and non-mulched soils at the harvest time in October at 0.37-0.44 mg/kg. With the amounts of residual film in farmland increasing from 0 kg/ha to 2700 kg/ha (equivalent to the total amount of residual film after 60 years of continuous plastic film mulching), the PAEs concentrations were no significant changes, being 0.54-0.93 mg/kg. Maize (Zea mays L.) roots could absorb and accumulate PAEs, and the bio-concentration factor (BCF) was 1.6-2.3, and the average PAEs concentrations in stems, leaves, and grains were 79%-80% of those in roots at 0.77-1.47 mg/kg. For the ingestion of maize grains or potato (Solanum tuberosum L.) tubers grown in plastic film mulched farmland or farmland containing residual film of 450-2700 kg/ha, the hazard index (HI) were less than 1, the carcinogenic risks (CRs) were 2.5 × 10-7-2.2 × 10-6, and the estrogenic equivalences were 6.17-17.73 ng E2/kg. This study provides important data for the risk management of PAEs in farmlands.

Reduction effects of solar radiation, mechanical tension, and soil burial on phthalate esters concentrations in plastic film and soils.

Phthalate esters (PAEs) are potentially dangerous chemicals in plastic film mulched fields; however, few studies have investigated how to reduce their concentrations in plastic film and soil. In this study, the effects of solar radiation, mechanical tension, and soil burial on PAEs concentrations in polyethylene (PE) film and degradable film were investigated, and the half-lives of di-n-butyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) in soil also studied. PAEs concentrations in polyethylene films were about twice those in the degradable films; however, PAEs concentrations in all experimental films were similar after 1-year of field exposure. Mechanical tension had no effect on the PAEs concentrations of polyethylene films, but increased the detected concentrations of PAEs in degradable films by 34%-120%. After 4-years of burial, the PAEs concentrations in films decreased by 79.2%-98.0%, and mechanical tension promoted the reductions. However, there was little difference in PAEs concentrations between the buried soils with and without films, indicating the released PAEs reduced quickly in soil. Also, the half-lives of DBP and DEHP were 2.4-4.6 days and 18.5-41.4 days, respectively. Overall, the results presented herein provide reasonable approaches to reduce the concentrations of PAEs in plastic films and soils.

Iron Chaperone Poly rC Binding Protein 1 Protects Mouse Liver From Lipid Peroxidation and Steatosis.

BACKGROUND AND AIMS: Iron is essential yet also highly chemically reactive and potentially toxic. The mechanisms that allow cells to use iron safely are not clear; defects in iron management are a causative factor in the cell-death pathway known as ferroptosis. Poly rC binding protein 1 (PCBP1) is a multifunctional protein that serves as a cytosolic iron chaperone, binding and transferring iron to recipient proteins in mammalian cells. Although PCBP1 distributes iron in cells, its role in managing iron in mammalian tissues remains open for study. The liver is highly specialized for iron uptake, utilization, storage, and secretion. APPROACH AND RESULTS: Mice lacking PCBP1 in hepatocytes exhibited defects in liver iron homeostasis with low levels of liver iron, reduced activity of iron enzymes, and misregulation of the cell-autonomous iron regulatory system. These mice spontaneously developed liver disease with hepatic steatosis, inflammation, and degeneration. Transcriptome analysis indicated activation of lipid biosynthetic and oxidative-stress response pathways, including the antiferroptotic mediator, glutathione peroxidase type 4. Although PCBP1-deleted livers were iron deficient, dietary iron supplementation did not prevent steatosis; instead, dietary iron restriction and antioxidant therapy with vitamin E prevented liver disease. PCBP1-deleted hepatocytes exhibited increased labile iron and production of reactive oxygen species (ROS), were hypersensitive to iron and pro-oxidants, and accumulated oxidatively damaged lipids because of the reactivity of unchaperoned iron. CONCLUSIONS: Unchaperoned iron in PCBP1-deleted mouse hepatocytes leads to production of ROS, resulting in lipid peroxidation (LPO) and steatosis in the absence of iron overload. The iron chaperone activity of PCBP1 is therefore critical for limiting the toxicity of cytosolic iron and may be a key factor in preventing the LPO that triggers the ferroptotic cell-death pathway.

Comparison of three neutralizing broths for environmental sampling of low levels of Listeria monocytogenes desiccated on stainless steel surfaces and exposed to quaternary ammonium compounds.

BACKGROUND: An effective environmental sampling method involves the use of a transport/neutralizing broth with the ability to neutralize sanitizer residues that are collected during sampling and to maintain viability of stressed Listeria monocytogenes (Lm) cells. RESULTS: We applied Lm onto stainless steel surfaces and then subjected Lm to desiccation stress for 16-18 h at room temperature (RT, 21-24 °C). This was followed by the subsequent application of Whisper™ V, a quaternary ammonium compound (QAC)-based sanitizer, diluted to 400 ppm and 8000 ppm of active quat, for 6 h. We then sampled Lm with sponges pre-moistened in three transport broths, Dey/Engley (D/E) broth, Letheen broth and HiCap™ broth, to generate environmental samples that contained sanitizer residues and low levels of stressed Lm, which were subsequently analyzed by an enrichment-based method. This scheme conformed with validation guidelines of AOAC International by using 20 environmental test portions per broth that contained low levels of Lm such that not all test portions were positive (i.e., fractional positive). We showed that D/E broth, Letheen broth and HiCap™ broth performed similarly when no quat or 400 ppm of quat was applied to the Lm contaminating stainless steel surfaces. However, when 8000 ppm of quat was applied, Letheen broth did not effectively neutralize the QAC in the samples. These comparisons were performed on samples stored under three conditions after collection to replicate scenarios of sample transport, RT for 2 h, 4 °C for 24 h and 4 °C for 72 h. Comparisons under the three different scenarios generally reached the same conclusions. In addition, we further demonstrated that storing Letheen and HiCap™ broths at RT for two months before sampling did not reduce their capacity to neutralize sanitizers. CONCLUSIONS: We developed a scheme to evaluate the ability of transport broths to neutralize QAC sanitizers. The three transport broths performed similarly with a commonly used concentration of quat, but Letheen broth could not effectively neutralize a very high concentration of QAC. The performance of transport broths was not significantly affected under the assessed pre-sampling and post-sampling storage conditions.

[Distribution Characteristics of Microplastics in Qingdao Coastal Beaches].

Microplastics (MPs, plastic fibers, debris, or particles that are generally smaller than 5 mm in diameter) can serve as carriers for hazardous substances, which are ingested by organisms in the ocean and can affect their growth and metabolism. Moreover, MPs will spread with ocean currents, and MP pollution has become a global problem. In this study, the MP abundance distribution of four typical beaches near the coast of Qingdao was studied by the combination of ordinary microscope and fluorescence microscope methods. In addition, the distribution of MPs collected from various beaches in different particle size ranges, shapes, and chemical compositions was discussed. Abundances on the sea surface varied between 5.05×103 particles·m-3 and 1.25×104 particles·m-3, and the concentration of MPs in sand varied between 1.91×103 particles·m-2 and 4.35×103 particles·m-2, with no significant differences detected among the four beaches examined. The results show the pervasiveness of MP pollution in coastal environments of Qingdao. The size of particles found in this study ranged from 5 mm to 50 µm, and increases in abundance were detected with the decreasing particle size. Polypropylene (PP), polyethylene (PE), polystyrene (PS), polyethylene terephthalate (PET), polyvinyl chloride (PVC), 96% polystyrene+4% butadiene copolymer (SB), polymethyl acrylate (PMA), and polyamide (PA) were present in seawater in coastal environments of Qingdao, and compared with the seawater samples, no PA or PMA were found in sand. Research results indicated that fiber was dominant in seawater and sand. MPs in the sand were similar to those in seawater in terms of the particle size, shape, and composition, thus indicating that the seawater and sand of the bathing beaches in Qingdao may have the same pollution sources, e. g., the packaging industry, clothing textile industry, and tourism. This paper studies the distribution and sources of MPs in the bathing beaches of Qingdao, and it provides basic data for research and supervision of environmental MP pollution in Chinese coastal zones.

[Instability of Mitochondrial DNA D-loop Region Genes in Patients with Leukemia].

OBJECTIVE: To study the instability of mitochondrial DNA（mt DNA） D-loop region genes in patients with Leukemia. METHODS: The HV-1 and HV-2 regions of D-loop region in 24 patients with leukemia were amplificated and sequenced, then their results were compared with revised Cambridge reference sequence (rCRS) and Databank mtDB. The mutation rate was detected by SPSS 22.0 statistics software. RESULTS: The total mutation rate in patients was 95.83% (23/24), the detection showed 82 mutated genes, out of which 47 (57.32%) mutated genes located in HV-1 region, 35 (42.68%) mutated genes in HV-2 region. The comparison showed that the mutation rate in untreated (UT) group and treated (T) group of AML patients was (2.37±0.82)×10-3 and (4.76±2.45)×10-3 respectively(P＜0.01), the mutation rate in PR and CR groups of treated AML patients was (5.10±2.56)×10-3 and (4.51±2.51)×10-3 respectively (P＜0.05), the comparison among M3 group showed that the mutation rates in UT, PR and CR groups were (2.55±0.63)×10-3, (5.37±3.41)×10-3 and (3.71±1.65)×10-3 respectively (P＞0.05). CONCLUSION: The more high mutation rate and many kinds of mutation types exist in D-loop region, suggesting that the genes in D-loop region display the more strong instability, the chemotherapy may aggravate the instability of genes in D-loop region.

Fate of four phthalate esters with presence of Karenia brevis: Uptake and biodegradation.

Phthalate esters (PAEs), one class of the most frequently detected endocrine-disrupting chemicals (EDCs) in marine environment, have aroused wide public concerns because of their carcinogenicity, teratogenicity, and mutagenicity. However, the environmental fate of PAEs in the occurrence of harmful algal blooms remains unclear. In this research, four PAEs with different alkyl chains, i.e., dimethyl phthalate (DMP), diethyl phthalate (DEP), diallyl phthalate (DAP), and dipropyl phtalate (DPrP) were selected as models to investigate toxicity, uptake, and degradation of PAEs in seawater grown with K. brevis, one of the common harmful red tide species. The 96-h median effective concentration (96h-EC50) values followed the order of DMP (over 0.257 mmol L-1) > DEP (0.178 mmol L-1) > DAP (0.136 mmol L-1) > DPrP (0.095 mmol L-1), and the bio-concentration factors (BCFs) were positively correlated to the alkyl chain length. These results indicate that the toxicity of PAEs and their accumulation in K. brevis increased with increasing alkyl chains, due to the higher lipophicity of the longer chain PAEs. With growth of K. brevis for 96 h, the content of DMP, DEP, DAP, and DPrP decreased by 93.3%, 68.2%, 57.4% and 46.7%, respectively, mainly attributed to their biodegradation by K. brevis, accounting for 87.1%, 61%, 46%, 40% of their initial contents, respectively. It was noticed that abiotic degradation had little contribution to the total reduction of PAEs in the algal cultivation systems. Moreover, five metabolites were detected in the K. brevis when exposed to DEP including dimethyl phthalate (DMP), monoethyl phthalate (MEP), mono-methyl phthalate (MMP), phthalic acid (PA), and protocatechuic acid (PrA). While when exposed with to DPrP, one additional intermediate compound diethyl phthalate (DEP) was detected in the cells of K. brevis in addition to the five metabolites mentioned above. These results confirm that the main biodegradation pathways of DEP and DPrP by K. brevis included de-esterification, demethylation or transesterification. These findings will provide valuable evidences for predicting the environmental fate and assessing potential risk of PAEs in the occurrence of harmful algal blooms in marine environment.

Plant toxin ß-ODAP activates integrin ß1 and focal adhesion: A critical pathway to cause neurolathyrism.

Neurolathyrism is a unique neurodegeneration disease caused by ß-N-oxalyl-L-α, ß- diaminopropionic (ß-ODAP) present in grass pea seed (Lathyrus stativus L.) and its pathogenetic mechanism is unclear. This issue has become a critical restriction to take full advantage of drought-tolerant grass pea as an elite germplasm resource under climate change. We found that, in a human glioma cell line, ß-ODAP treatment decreased mitochondrial membrane potential, leading to outside release and overfall of Ca2+ from mitochondria to cellular matrix. Increased Ca2+ in cellular matrix activated the pathway of ECM, and brought about the overexpression of ß1 integrin on cytomembrane surface and the phosphorylation of focal adhesion kinase (FAK). The formation of high concentration of FA units on the cell microfilaments further induced overexpression of paxillin, and then inhibited cytoskeleton polymerization. This phenomenon turned to cause serious cell microfilaments distortion and ultimately cytoskeleton collapse. We also conducted qRT-PCR verification on RNA-sequence data using 8 randomly chosen genes of pathway enrichment, and confirmed that the data was statistically reliable. For the first time, we proposed a relatively complete signal pathway to neurolathyrism. This work would help open a new window to cure neurolathyrism, and fully utilize grass pea germplasm resource under climate change.

Identifying anticancer peptides by using improved hybrid compositions.

Cancer is one of the main causes of threats to human life. Identification of anticancer peptides is important for developing effective anticancer drugs. In this paper, we developed an improved predictor to identify the anticancer peptides. The amino acid composition (AAC), the average chemical shifts (acACS) and the reduced amino acid composition (RAAC) were selected to predict the anticancer peptides by using the support vector machine (SVM). The overall prediction accuracy reaches to 93.61% in jackknife test. The results indicated that the combined parameter was helpful to the prediction for anticancer peptides.

Aging of Zerovalent Iron in Synthetic Groundwater: X-ray Photoelectron Spectroscopy Depth Profiling Characterization and Depassivation with Uniform Magnetic Field.

Scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) depth profiling were employed to characterize the aged zerovalent iron (AZVI) samples incubated in synthetic groundwater. The AZVI samples prepared under different conditions exhibited the passive layers of different morphologies, amounts, and constituents. Owing to the accumulation of iron oxides on their surface, all the prepared AZVI samples were much less reactive than the pristine ZVI for Se(IV) removal. However, the reactivity of all AZVI samples toward Se(IV) sequestration could be significantly enhanced by applying a uniform magnetic field (UMF). Moreover, the flux intensity of UMF necessary to depassivate an AZVI sample was strongly dependent on the properties of its passive layer. The UMF of 1 mT was strong enough to restore the reactivity of the AZVI samples with Fe3O4 as the major constituent of the passive film or with a thin layer of α-Fe2O3 and γ-FeOOH in the external passive film. The flux intensity of UMF necessary to depassivate the AZVI samples would increase to 2 mT or even 5 mT if the AZVI samples were covered with passive films being thicker, denser, and contained more γ-FeOOH and α-Fe2O3. Furthermore, increasing the flux intensity of UMF facilitated the reduction of Se(IV) to Se(0) by AZVI samples.

Detection of phthalate esters in seawater by stir bar sorptive extraction and gas chromatography-mass spectrometry.

We developed the stir bar sorptive extraction (SBSE)-gas chromatography-mass spectrometry (GC-MS) method to detect 15 kinds of PAEs in seawater. The stir bars (20mm in length and 1mm in film thickness) coated with 150µL of polydimethylsiloxane (PDMS) were found to demonstrate the optimal extraction of PAEs. The optimal conditions were as follows: extraction time of 2h, extraction temperature of 25°C, sodium chloride of 5%, methanol of 10%, analytical time of 50min, and methanol-acetonitrile (4:1) as the solvent. SBSE-GC-MS revealed that under the set temperature, the chromatographic peaks of all 15 PAEs can appear with complete separation. The detection limit ranged from 0.07µg/L to 5.71µg/L, whereas the limit of quantification ranged from 0.023µg/L to 193µg/L, and the correlation coefficients between the chromatographic peak area and concentration of the PAEs were greater than 0.92.