Establishment of a Sensitive and Reliable Droplet Digital PCR Assay for the Detection of Bursaphelenchus xylophilus.

Pine wilt disease (PWD), which poses a significant risk to pine plantations across the globe, is caused by the pathogenic agent Bursaphelenchus xylophilus, also referred to as the pine wood nematode (PWN). A droplet digital PCR (ddPCR) assay was developed for the quick identification of the PWN in order to improve detection sensitivity. The research findings indicate that the ddPCR assay demonstrated significantly higher analysis sensitivity and detection sensitivity in comparison to traditional quantitative PCR (qPCR). However, it had a more limited dynamic range. High specificity was shown by both the ddPCR and qPCR techniques in the diagnosis of the PWN. Assessments of reproducibility revealed that ddPCR had lower coefficients of variation at every template concentration. Inhibition tests showed that ddPCR was less susceptible to inhibitors. There was a strong linear association between standard template measurements obtained using ddPCR and qPCR (Pearson correlation = 0.9317; p < 0.001). Likewise, there was strong agreement (Pearson correlation = 0.9348; p < 0.001) between ddPCR and qPCR measurements in the evaluation of pine wood samples. Additionally, wood samples from symptomatic (100% versus 86.67%) and asymptomatic (31.43% versus 2.9%) pine trees were diagnosed with greater detection rates using ddPCR. This study's conclusions highlight the advantages of the ddPCR assay over qPCR for the quantitative detection of the PWN. This method has a lot of potential for ecological research on PWD and use in quarantines.

Catalytically active prokaryotic Argonautes employ phospholipase D family proteins to strengthen immunity against different genetic invaders.

Prokaryotic Argonautes (pAgos) provide bacteria and archaea with immunity against plasmids and viruses. Catalytically active pAgos utilize short oligonucleotides as guides to directly cleave foreign nucleic acids, while inactive pAgos lacking catalytic residues employ auxiliary effectors, such as nonspecific nucleases, to trigger abortive infection upon detection of foreign nucleic acids. Here, we report a unique group of catalytically active pAgo proteins that frequently associate with a phospholipase D (PLD) family protein. We demonstrate that this particular system employs the catalytic center of the associated PLD protein rather than that of pAgo to restrict plasmid DNA, while interestingly, its immunity against a single-stranded DNA virus relies on the pAgo catalytic center and is enhanced by the PLD protein. We also find that this system selectively suppresses viral DNA propagation without inducing noticeable abortive infection outcomes. Moreover, the pAgo protein alone enhances gene editing, which is unexpectedly inhibited by the PLD protein. Our data highlight the ability of catalytically active pAgo proteins to employ auxiliary proteins to strengthen the targeted eradication of different genetic invaders and underline the trend of PLD nucleases to participate in host immunity.

Effects of coordinated regulation of water, nitrogen, and biochar on the yield and soil greenhouse gas emission intensity of greenhouse tomatoes.

Regulating the coupled relationship among water, nitrogen, and biochar is an effective strategy for increasing production and reducing emissions in greenhouse agriculture. However, a comprehensive evaluation model remains lacking. Toward this end, we aimed to evaluate the emission patterns of greenhouse gases and greenhouse tomato yield during the spring and autumn cultivation seasons as influenced by irrigation water use efficiency, nitrogen fertilizer partial productivity, and soil organic carbon (SOC). We applied three irrigation levels: 100% (W1), 80% (W2), and 60% (W3) of the reference crop evapotranspiration; three nitrogen application levels: 240, 192, and 144 kg ha-1, representing 100% (N1), 80% (N2), and 60% (N3) of the actual local application amount; and four biochar application gradients: B0, B1, B2, and B3 corresponding to 0, 30, 50, and 70 t ha-1, respectively. Interaction experiments were conducted based on the implementation the incomplete multifactorial design, using W1N1B0 as the control. The entropy weight method was used to calculate the main and sub-weights of the evaluation indicators. During the growing season, greenhouse gas emissions have a significant impact. The cumulative emissions of CO2, N2O, and CH4 from soil in spring are 24.4%, 42.18%, and 13.9% higher than those in autumn, respectively. Soil temperature was a key environmental factor influencing soil CO2 emissions, while soil moisture content and nitrogen fertilizer input efficiency were the main factors affecting soil N2O emissions, and the correlation between soil CH4 emissions and soil organic carbon content was most significant. Water-nitrogen-biochar interaction significantly affected yield and GHGI: adding biochar under the same water-nitrogen- and moderately deficient irrigation(W1) under the same nitrogen-biochar application modes increased yield and reduced GHGI. However, moderately reduced nitrogen application decreased(N2) both measures under the same water-biochar application mode. The VIKOR comprehensive evaluation method determined W2N2B2 as the most suitable water-nitrogen-biochar application mode for optimizing yield and GHGI. This study provides a theoretical basis for stable, low-carbon development in green-intensive agriculture.

Molecular Interactions Governing the Rat Aryl Hydrocarbon Receptor Activities of Polycyclic Aromatic Compounds and Predictive Model Development.

Polycyclic aromatic compounds (PACs) exhibit rat aryl hydrocarbon receptor (rAhR) activities, leading to diverse biological or toxic effects. In this study, the key amino residues and molecular interactions that govern the rAhR activity of PACs were investigated using in silico strategies. The homology model of rAhR was first docked with 90 PACs to yield complexes, and the results of the molecular dynamics simulations of 16 typical complexes showed that the binding energies of the complexes range from -7.37 to -26.39 kcal/mol. The major contribution to the molecular interaction comes from van der Waals forces, and Pro295 and Arg316 become the key residues involved in most complexes. Two QSAR models were further developed to predict the rAhR activity of PACs (in terms of log IEQ for PACs without halogen substitutions and log%-TCDD-max for halogenated PACs). Both models have good predictive ability, robustness, and extrapolation ability. Molecular polarizability, electronegativity, size, and nucleophilicity are identified as the important factors affecting the rAhR activity of PACs. The developed models could be employed to predict the rAhR activity of other reactive PACs. This work provides insight into the mechanisms and interactions of the rAhR activity of PACs and assists in the assessment of their fate and risk in organisms.

Effects of aripiprazole on prolactin levels and differences in effectiveness in patients with schizophrenia: a post-hoc analysis of the real-world data of a multicenter study.

Objectives: To investigate the effect of aripiprazole on prolactin levels in patients with schizophrenia and analyze whether varying baseline prolactin levels affect the effectiveness and safety of aripiprazole, in a real-life diagnostic and therapeutic setting in a post-hoc analysis. Methods: In this post-hoc analysis, patients with schizophrenia in the acute phase were divided into an elevated-prolactin group and a normal-prolactin group. After 8 weeks of aripiprazole treatment, changes in the proportion of patients with an abnormal prolactin level were analyzed in both groups, and the efficacy and safety of aripiprazole were compared between the two groups. Results: The elevated-prolactin group had more women, a longer duration of disease, and lower Positive and Negative Syndrome Scale (PANSS) total and subscale scores at baseline compared with the normal-prolactin group (all P < 0.05), and there was no significant difference in the proportion of patients with prior use of antipsychotic medication between the two groups. Regardless of previous antipsychotic use, patients in both groups developed hyperprolactinemia (23/168 [13.7%] in those who had taken antipsychotics vs. 43/375 [11.4%] in those who had not). After 8 weeks of aripiprazole treatment, the proportion of patients with abnormal prolactin in the elevated-prolactin group significantly decreased with prolonged treatment (P < 0.001), and aripiprazole had no significant effect on the normal-prolactin group (P = 0.250). Normal-prolactin group showed better efficacy than the elevated-prolactin group, and the differences in efficacy between the two groups was observed from week 4 to the endpoint (all p<0.05). In total, 87.2% (68/78) patients experienced mild to moderate adverse events in the elevated-prolactin group, which was significantly more frequent compared with the normal-prolactin group 71.0% (365/514). Conclusions: In this real-world study, for patients with acute schizophrenia, aripiprazole was effective in lowering the proportion of patients with abnormal prolactin levels, while it had no significant effect on patients with normal baseline prolactin. After adjusting for factors such as sex, age, prior antipsychotic drugs use history and disease severity, effectiveness and safety of aripiprazole in patients with normal baseline prolactin was significantly better than that in patients with elevated baseline prolactin.

Aflatoxins in dried chilli products in Gansu Province and health risk.

In order to understand the status of aflatoxin contamination in dried chilli products in Gansu Province and the risk of dietary exposure, a total of 106 samples of dried chilli products from farmers' markets and supermarkets in 14 prefecture-cities of Gansu Province were collected and analysed by isotope dilution liquid chromatography-tandem mass spectrometry. The results showed that the detection rate of aflatoxin in dried chilli products in Gansu Province was 30.2%, and the average level was 1.57 µg/kg. The detection rates of dried chillies, paprika, and chilli powders were 16.7%, 43.6%, and 46.2%, respectively. The detection rates of aflatoxin in dried chilli products from shops and farmers' markets were 22.5% and 40.0%, respectively. The dietary exposure of AFB1 was 0.0001 µg/kg bw/day, and the MOE calculated from its average concentration was 305.

Machine learning models for daily net radiation prediction across different climatic zones of China.

Net radiation (Rn), a critical component in land surface energy cycling, is calculated as the difference between net shortwave radiation and longwave radiation at the Earth's surface and holds significant importance in crop models for precision agriculture management. In this study, we examined the performance of four machine learning models, including extreme learning machine (ELM), hybrid artificial neural networks with genetic algorithm models (GANN), generalized regression neural networks (GRNN), and random forests (RF), in estimating daily Rn at four representative sites across different climatic zones of China. The input variables included common meteorological factors such as minimum and maximum temperature, relative humidity, sunshine duration, and shortwave solar radiation. Model performance was assessed and compared using statistical parameters such as the correlation coefficient (R2), root mean square errors (RMSE), mean absolute errors (MAE), and Nash-Sutcliffe coefficient (NS). The results indicated that all models slightly underestimated actual Rn, with linear regression slopes ranging from 0.810 to 0.870 across different zones. The estimated Rn was found to be comparable to observed values in terms of data distribution characteristics. Among the models, the ELM and GANN demonstrated higher consistency with observed values, exhibiting R2 values ranging from 0.838 to 0.963 and 0.836 to 0.963, respectively, across varying climatic zones. These values surpassed those of the RF (0.809-0.959) and GRNN (0.812-0.949) models. Additionally, the ELM and GANN models showed smaller simulation errors in terms of RMSE, MAE, and NS across the four climatic zones compared to the RF and GRNN models. Overall, the ELM and GANN models outperformed the RF and GRNN models. Notably, the ELM model's faster computational speed makes it a strong recommendation for Rn estimates across different climatic zones of China.

Gas-phase and air-solid interface behavior of phthalate plasticizer and ozone: The influence of indoor mineral dust.

Indoor environments serve as reservoirs for a variety of emerging pollutants (EPs), such as phthalates (PAE), with intricate interactions occurring between these compounds and indoor oxidants alongside dust particles. However, the precise mechanisms governing these interactions and their resulting environmental implications remain unclear. By theoretical simulations, this work uncovers multi-functional compounds and high oxygen molecules as important products arising from the interaction between DEP/DEHP and O3, which are closely linked to SOA formation. Further analysis reveals a strong affinity of DEP/DEHP for mineral dust surfaces, with an adsorption energy of 22.11/30.91 kcal mol-1, consistent with a higher concentration of DEHP on the dust surface. Importantly, mineral particles are found to inhibit every step of the reaction process, albeit resulting in lower product toxicity compared to the parent compounds. Thus, timely removal of dust in an indoor environment may reduce the accumulation and residue of PAEs indoors, and further reduce the combined exposure risk produced by PAEs-dust. This study aims to enhance our understanding of the interaction between PAEs and SOA formation, and to develop a fundamental reaction model at the air-solid surface, thereby shedding light on the microscopic behaviors and pollution mechanisms of phthalates on indoor dust surfaces.

Engineered minimal type I CRISPR-Cas system for transcriptional activation and base editing in human cells.

Type I CRISPR-Cas systems are widespread and have exhibited high versatility and efficiency in genome editing and gene regulation in prokaryotes. However, due to the multi-subunit composition and large size, their application in eukaryotes has not been thoroughly investigated. Here, we demonstrate that the type I-F2 Cascade, the most compact among type I systems, with a total gene size smaller than that of SpCas9, can be developed for transcriptional activation in human cells. The efficiency of the engineered I-F2 tool can match or surpass that of dCas9. Additionally, we create a base editor using the I-F2 Cascade, which induces a considerably wide editing window (~30 nt) with a bimodal distribution. It can expand targetable sites, which is useful for disrupting functional sequences and genetic screening. This research underscores the application of compact type I systems in eukaryotes, particularly in the development of a base editor with a wide editing window.

Automatic recognition system for concrete cracks with support vector machine based on crack features.

Cracks are a common problem in concrete surfaces. With the continuous optimization of machine vision-based inspection systems, effective crack detection and recognition is the core of the entire system. In this study, support vector machine (SVM) was used to distinguish cracks from other regions. To complete the recognition system of the SVM, a framework consisting of an image processing and recognition model was proposed. An algorithm combining the Prewitt operator with the Otsu threshold was proposed for image segmentation. The binary image processed by the new algorithm combined with mathematical morphology can result in a more complete crack zone and fewer interference regions. After the initial parameter extraction, most of the impurity areas were screened by preliminary discrimination, removing 99% of the impurities. This processing step ensured the balance and effectiveness of the samples. To establish an automatic identification model based on SVM with a radial basis function, compactness, occupancy rate, and length-width ratio were selected as input parameters after comparing these three features with all six features of the crack. The recognition accuracy of this system reaches 97.14%, demonstrating that the proposed method is effective and satisfies practical requirements.

Computational simulations uncover enantioselective metabolism of chiral triazole fungicides by human CYP450 enzymes: A case study of tebuconazole.

Tebuconazole (TEB), a prominent chiral triazole fungicide, has been extensively utilized for plant pathogen control globally. Despite experimental evidence of TEB metabolism in mammals, the enantioselectivity in the biotransformation of R- and S-TEB enantiomers by specific CYP450s remains elusive. In this work, integrated in silico simulations were employed to unveil the binding interactions and enantioselective metabolic fate of TEB enantiomers within human CYP1A2, 2B6, 2E1, and 3A4. Molecular dynamics (MD) simulations clearly delineated the binding specificity of R- and S-TEB to the four CYP450s, crucially determining their differences in metabolic activity and enantioselectivity. The primary driving force for robust ligand binding was identified as van der Waals interactions with CYP450s, particularly involving the hydrophobic residues. Mechanistic insights derived from quantum mechanics/molecular mechanics (QM/MM) calculations established C2-methyl hydroxylation as the predominant route of R-/S-TEB metabolism, while C6-hydroxylation and triazol epoxidation were deemed kinetically infeasible pathways. Specifically, the resulting hydroxy-R-TEB metabolite primarily originates from R-TEB biotransformation by 1A2, 2E1 and 3A4, whereas hydroxy-S-TEB is preferentially produced by 2B6. These findings significantly contribute to our comprehension of the binding specificity and enantioselective metabolic fate of chiral TEB by CYP450s, potentially informing further research on human health risk assessment associated with TEB exposure.

Multifunctional targeting of docetaxel plus bakuchiol micelles in the treatment of invasion and metastasis of ovarian cancer.

The invasion and metastasis of tumors pose significant challenges in the treatment of ovarian cancer (OC), making it difficult to cure. One potential treatment approach that has gained attention is the use of matrix metalloproteinase reactive controlled release micelle preparations. In this study, we developed a novel PEG5000-PVGLIG-hyaluronic acid docetaxel/bakuchiol (PP-HA-DTX/BAK) micelles formulation with desirable characteristics such as particle size, narrow polydispersity index, and a ZETA potential of approximately -5 mV. The surface modification with HA facilitates tumor penetration into the tumor interior, while the incorporation of DSPE-PEG2000-PVGLIG-PEG5000helps conceal DSPE-PEG2000-HA, reducing off-target effects and prolonging drug circulation timein vivo. Bothin vitroandin vivoexperiments demonstrated that these micelles effectively inhibit proliferation, invasion, and metastasis of OC cells while promoting apoptosis. Therefore, our findings suggest that PP-HA-DTX/BAK micelles represent a safe and effective therapeutic strategy for treating OC.

OsWNK9 regulates cadmium concentration in brown rice by restraining cadmium transport from straw to brown rice.

Selecting and breeding rice cultivars that enable strong cadmium (Cd) accumulation in rice straw but low accumulation in brown rice is a promising way to achieve Cd phytoremediation as well as to ensure the food safety of rice. Herein, we isolated a gene OsWNK9 from the quantitative trait locus associated with reducing Cd translocation from rice straw to brown rice and decreasing the Cd concentration in brown rice (BRCdC). Continuous strong expression of OsWNK9 was observed in nodes and internode and was induced after Cd supply. OsWNK9 was localized in the rice cell nucleus and participated in the regulation of Cd transport in yeast. Two independent oswnk9 rice mutants were generated via CRISPR/Cas9 gene-editing and showed significantly higher BRCdC than that of the wild type (WT). The BRCdC of knockout oswnk9 mutants was 0.227 mg kg-1and 0.238 mg kg-1, increased by 14 % and 19 % compared with that of the WT due to the lower Cd allocation in the basal stem, internode, and node III, which was unrelated to Cd uptake. Interestingly, OsWNK9 could promote iron (Fe) accumulation in rice under Cd-contaminated conditions, suggesting that OsWNK9 is an ideal gene for Cd phytoremediation and Fe biofortification in rice to support safe food production.

Theoretical studies on the aqueous phase and graphene heterogeneous degradation of acrylamide and acrylonitrile by HO, ClO, and BrO radicals.

The newly discovered ClO• and BrO• contribute to pollutant degradation in advanced oxidation processes, while acrylamide (AM) and acrylonitrile (ACN) are always the focus of scientists concerned due to their continuous production and highly toxic effects. Moreover, various particles with a graphene-like structure are the companions of AM/ACN in dry/wet sedimentation or aqueous phase existence, which play an important role in heterogeneous oxidation. Thus, this work focuses on the reaction mechanism and environmental effect of AM/ACN with ClO•/BrO•/HO• in the water environment under the influence of graphene (GP). The results show that although the reactivity sequence of AM and ACN takes the order of with HO• > with BrO• > with ClO•, the easiest channel always occurs at the same C-position of the two reactants. The reaction rate constants (k) of AM with three radicals are 2 times larger than that with ACN, and amide groups have a better ability to activate CC bonds than cyanide groups. The existence of GP can accelerate the target reaction, and the k increased by 9-13 orders of magnitude. The toxicity assessment results show that the toxic effect of most products is lower than that of parent compounds, but the environmental risk of products from ClO•/BrO•-adducts is higher than those from HO•-adducts. The oxidative degradation process based on ClO• and BrO• deserves special attention, and the catalytic effect of GP and its derivatives on the oxidation process is non-negligible.

Insight into oil-water interfacial adsorption of protein particles towards regulating Pickering emulsions: A review.

Over the past decade, Pickering emulsions (PEs) stabilized by protein particles have been the focus of researches. The characteristics of protein particles at the oil-water interface are crucial for stabilizing PEs. The unique adsorption behaviors of protein particles and various modification methods enable oil-water interface to exhibit controllable regulation strategies. However, from the perspective of the interface, studies on the regulation of PEs by the adsorption behaviors of protein particles at oil-water interface are limited. Therefore, this review provides an in-depth study on oil-water interfacial adsorption of protein particles and their regulation on PEs. Specifically, the formation of interfacial layer and effects of their interfacial characteristics on PEs stabilized by protein particles are elaborated. Particularly, complicated behaviors, including adsorption, arrangement and deformation of protein particles at the oil-water interface are the premise of affecting the formation of interfacial layer. Moreover, the particle size, surface charge, shape and wettability greatly affect interfacial adsorption behaviors of protein particles. Importantly, stabilities of protein particles-based PEs also depend on properties of interfacial layers, including interfacial layer thickness and interfacial rheology. This review provides useful insights for the development of PEs stabilized by protein particles based on interfacial design.

The effect of different amendments on Cd availability and bacterial community after three-year consecutive application in Cd-contaminated paddy soils.

In situ immobilization is a widely used measure for passivating Cd-contaminated soils. Amendments need to be continuously applied to achieve stable remediation effects. However, few studies have evaluated the impact of consecutive application of amendments on soil health and the microecological environment. A field experiment was conducted in a Cd-contaminated paddy (available Cd concentration 0.40 mg kg-1) on the Chengdu Plain to investigate the changes in soil Cd availability and response characteristics of soil bacterial communities after consecutive application of rice straw biochar (SW), fly ash (FM) and marble powder (YH) amendments from 2018 to 2020. Compared with control treatment without amendments (CK), soil pH increased by 0.6, 0.5 and 1.5 under SW, FM and YH amendments, respectively, and the soil available Cd concentration decreased by 10.71%, 21.42% and 25.00%, respectively. The Cd concentration in rice grain was less than 0.2 mg kg-1 under YH amendment, which was within the Chinese Contaminant Limit in Food of National Food Safety Standards (GB2762-2022) in the second and third years. The three amendments had different effects on the transformation of Cd fractions in soil, which may be relevant to the specific bacterial communities shaped under different treatments. The proportion of Fe-Mn oxide-bound fraction Cd (OX-Cd) increased by 11% under YH treatment, which may be due to the promotion of Fe(III) and Cd binding by some enriched iron-oxidizing bacteria, such as Lysobacter, uncultured_Pelobacter sp. and Sulfurifusis. Candidatus_Tenderia and Sideroxydans were enriched under SW and FM amendments, respectively, and were likely beneficial for reducing Cd availability in soil through Cd immobilization. These results revealed the significance of the bacterial community in soil Cd immobilization after consecutive application of amendments and highlighted the potential of applying YH amendment to ensure the safe production of rice in Cd-contaminated soil.

New insight into the role of the self-assembly of heteroatom compounds in heavy oil viscosity enhancement.

Unveiling the role of heteroatom compounds in heavy oil viscosity is pivotal for finding targeted viscosity reduction methods to improve oil recovery. This research investigates the impact of heteroatoms in asphaltene molecules by utilizing quantum chemical calculations and molecular dynamics simulations to analyze their electrostatic potential characteristics, pairwise interactions, and dynamic behavior within realistic reservoirs. Heteroatom compounds can influence the molecular-level properties of asphaltenes and thus impact the macroscopic behavior of heavy oils. Research results suggest that the presence of ketone and aromatic rings in asphaltene molecules leads to the unrestricted movement of pi electrons due to their collective electronegativity. Two distinct configurations of asphaltene dimers, face-to-face, and edge-to-face, were observed. Intermolecular interactions were predominantly governed by van der Waals forces, highlighting their significant role in stabilizing asphaltene aggregates. The distribution of asphaltene molecules in the oil phase can be summarized as the "rebar-cement" theory. In the heteroatom-free system, the face-to-face peaks in the radial distribution function exhibit significantly reduced magnitudes compared to those in the heteroatom-containing system. This emphasizes the pivotal function of heteroatoms in connecting molecular components to form a more compact asphaltene structure, which may result in a higher viscosity of heavy oil. These findings give insight into the significance of heteroatoms in bridging molecular components and shaping the intricate structure of asphaltene and advance our understanding of heavy oil viscosity properties.

Physiological and molecular responses in phosphorus-hyperaccumulating Polygonum species to high phosphorus exposure.

Phosphorus (P)-hyperaccumulators for phytoextraction from P-polluted areas generally show rapid growth and accumulate large amounts of P without any toxicity symptom, which depends on a range of physiological processes and gene expression patterns that have never been explored. We investigated growth, leaf element concentrations, P fractions, photosynthetic traits, and leaf metabolome and transcriptome response in amphibious P-hyperaccumulators, Polygonum hydropiper and P. lapathifolium, to high-P exposure (5 mmol L-1), with 0.05 mmol L-1 as the control. Under high-P exposure, both species demonstrated good growth, allocating more P to metabolite P and inorganic P (Pi) accompanied by high potassium and calcium. The expression of a cluster of unigenes associated with photosynthesis was maintained or increased in P. lapathifolium, explaining the increase in net photosynthetic rate and the rapid growth under high-P exposure. Metabolites of trehalose metabolism, including trehalose 6-phosphate and trehalose, were sharply increased in both species by the high-P exposure, in line with the enhanced expression of associated unigenes, indicating that trehalose metabolic pathway was closely related to high-P tolerance. These findings elucidated the physiological and molecular responses involved in the photosynthesis and trehalose metabolism in P-hyperaccumulators to high-P exposure, and provides potential regulatory pathways to improve the P-phytoextraction capability.

Dihalogenated nitrophenols in drinking water: Prevalence, resistance to household treatment, and cardiotoxic impact on zebrafish embryo.

Dihalogenated nitrophenols (2,6-DHNPs), an emerging group of aromatic disinfection byproducts (DBPs) detected in drinking water, have limited available information regarding their persistence and toxicological risks. The present study found that 2,6-DHNPs are resistant to major drinking water treatment processes (sedimentation and filtration) and households methods (boiling, filtration, microwave irradiation, and ultrasonic cleaning). To further assess their health risks, we conducted a series of toxicology studies using zebrafish embryos as the model organism. Our findings reveal that these emerging 2,6-DHNPs showed lethal toxicity 248 times greater than that of the regulated DBP, dichloroacetic acid. Specifically, at sublethal concentrations, exposure to 2,6-DHNPs generated reactive oxygen species (ROS), caused apoptosis, inhibited cardiac looping, and induced cardiac failure in zebrafish. Remarkably, the use of a ROS scavenger, N-acetyl-l-cysteine, considerably mitigated these adverse effects, emphasizing the essential role of ROS in 2,6-DHNP-induced cardiotoxicity. Our findings highlight the cardiotoxic potential of 2,6-DHNPs in drinking water even at low concentrations of 19 µg/L and the beneficial effect of N-acetyl-l-cysteine in alleviating the 2,6-DHNP-induced cardiotoxicity. This study underscores the urgent need for increased scrutiny of these emerging compounds in public health discussions.

Chlorination of Aromatic Amino Acids: Elucidating Disinfection Byproducts, Reaction Kinetics, and Influence Factors.

In the face of ongoing water pollution challenges, the intricate interplay between dissolved organic matter and disinfectants like chlorine gives rise to potentially harmful disinfection byproducts (DBPs) during water treatment. The exploration of DBP formation originating from amino acids (AA) is a critical focus of global research. Aromatic DBPs, in particular, have garnered considerable attention due to their markedly higher toxicity compared to their aliphatic counterparts. This work seeks to advance the understanding of DBP formation by investigating chlorination disinfection and kinetics using tyrosine (Tyr), phenylalanine (Phe), and tryptophan (Trp) as precursors. Via rigorous experiments, a total of 15 distinct DBPs with accurate molecular structures were successfully identified. The chlorination of all three AAs yielded highly toxic chlorophenylacetonitriles (CPANs), and the disinfectant dosage and pH value of the reaction system potentially influence chlorination kinetics. Notably, Phe exhibited the highest degradation rate compared to Tyr and Trp, at both the CAA:CHOCl ratio of within 1:2 and a wide pH range (6.0 to 9.0). Additionally, a neutral pH environment triggered the maximal reaction rates of the three AAs, while an acidic condition may reduce their reactivity. Overall, this study aims to augment the DBP database and foster a deeper comprehension of the DBP formation and relevant kinetics underlying the chlorination of aromatic AAs.