PI3K/Akt/FoxO Pathway Mediates Antagonistic Toxicity in HepG2 Cells Coexposed to Deoxynivalenol and Enniatins.

The emerging mycotoxins enniatins (ENNs) and the traditional mycotoxin deoxynivalenol (DON) often co-contaminate various grain raw materials and foods. While the liver is their common target organ, the mechanism of their combined effect remains unclear. In this study, the combined cytotoxic effects of four ENNs (ENA, ENA1, ENB, and ENB1) with DON and their mechanisms were investigated using the HepG2 cell line. Additionally, a population exposure risk assessment of these mycotoxins was performed by using in vitro experiments and computer simulations. The results showed that only ENA at 1/4 IC50 and ENB1 at 1/8 IC50 coexposed with DON showed an additive effect, while ENB showed the strongest antagonism at IC50 (CI = 3.890). Co-incubation of ENNs regulated the signaling molecule levels which were disrupted by DON. Transcriptome analysis showed that ENB (IC50) up-regulated the PI3K/Akt/FoxO signaling pathway and inhibited the expression of apoptotic genes (Bax, P53, Caspase 3, etc.) via phosphorylation of FoxO, thereby reducing the cytotoxic effects caused by DON. Both types of mycotoxins posed serious health risks, and the cumulative risk of coexposure was particularly important for emerging mycotoxins.

Antimicrobial carbon dots/pectin-based hydrogel for promoting healing processes in multidrug-resistant bacteria-infected wounds.

Multidrug-resistant (MDR) bacterial infections have become a significant threat to global healthcare systems. Here, we developed a highly efficient antimicrobial hydrogel using environmentally friendly garlic carbon dots, pectin, and acrylic acid. The hydrogel had a porous three-dimensional network structure, which endowed it with good mechanical properties and compression recovery performance. The hydrogel could adhere closely to skin tissues and had an equilibrium swelling ratio of 6.21, indicating its potential as a wound dressing. In particular, the bactericidal efficacy following 24-h contact against two MDR bacteria could exceed 99.99 %. When the hydrogel was applied to epidermal wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) on mice, a remarkable healing rate of 93.29 % was observed after 10 days. This was better than the effectiveness of the traditionally used antibiotic kanamycin, which resulted in a healing rate of 70.36 %. In vitro cytotoxicity testing and hemolysis assay demonstrated a high biocompatibility. This was further proved by the in vivo assay where no toxic side effects were observed on the heart, liver, spleen, lung, or kidney of mice. This eco-friendly and easy-to-prepare food-inspired hydrogel provides an idea for the rational use of food and food by-products as a wound dressing to control MDR bacterial infections.

Reduction Foodborne Pathogens and Surrogate Microorganism on Citrus Fruits after Lab- and Pilot-scale Finishing Wax Application.

After finishing waxes are applied, citrus fruits are typically dried at 32-60°C for 2-3 min before final packing. The survival of Listeria monocytogenes, Salmonella, and Enterococcus faecium NRRL B-2354 was evaluated under laboratory conditions on lemons after applying one of four finishing waxes (F4, F6, F8, and F15) followed by an ambient hold or heated (50 or 60°C) drying step. The reduction of inoculated microorganisms during drying was significantly influenced by wax type and temperature, with greater reductions at higher temperatures. Greater reductions after waxing and drying at 60°C were observed with L. monocytogenes (2.84-4.44 log) than with Salmonella (1.65-3.67 log), and with Salmonella than with E. faecium (0.99-2.93 log). The survival of Salmonella inoculated at 5.8-5.9 log/fruit on lemons and oranges after applying wax F6 and drying at 60°C was evaluated during storage at 4 and 22°C. The reductions of Salmonella after waxing and drying were 1.7 log; additional reductions during storage at 4 or 22°C were 1.40-1.43 or 0.18-0.29 log, respectively, on waxed lemons, and 0.56-1.02 or 0.54-0.57 log, respectively, on waxed oranges. Under pilot-scale packinghouse conditions with wax F4, mean and minimum reductions of E. faecium ranged from 2.15 to 2.89 and 1.64 to 2.12 log, respectively. However, E. faecium was recovered by whole-fruit enrichment (limit of detection: 0.60 log CFU/lemon) but not by plating (LOD: 1.3 log CFU/lemon) from uninoculated lemons run with or after the inoculated lemons. The findings should provide useful information to establish and implement packinghouse food safety plans.

Allergenicity of alternative proteins: research hotspots, new findings, evaluation strategies, regulatory status, and future trends: a bibliometric analysis.

As the world population rises, the demand for protein increases, leading to a widening gap in protein supply. There is an unprecedented interest in the development of alternative proteins, but their allergenicity has raised consumer concerns. This review aims to highlight and correlate the current research status of allergenicity studies on alternative proteins based on previously published studies. Current research keywords, hotspots and trends in alternative protein sensitization were analyzed using a mixed-method approach that combined bibliometric analysis and literature review. According to the bibliometric analysis, current research is primarily focused on food science, agriculture, and immunology. There are significant variations in the type and amount of allergens found in alternative proteins. A significant amount of research has been focused on studying plant-based proteins and the cross-reactivity of insect proteins. The allergenicity of alternative proteins has not been studied extensively or in depth. The allergenicity of other alternative proteins and the underlying mechanisms warrant further study. In addition, the lack of a standardized allergy assessment strategy calls for additional efforts by international organizations and collaborations among different countries. This review provides new research and regulatory perspectives for the safe utilization of alternative proteins in human food systems.

Investigating enzyme kinetics and fluorescence sensing strategy of CRISPR/Cas12a for foodborne pathogenic bacteria.

Foodborne pathogenic bacteria are widespread in various foods, whose cross-contamination and re-contamination are critical influences on food safety. Rapid, accurate, and sensitive detection of foodborne pathogenic bacteria remains a topic of concern. CRISPR/Cas12a can recognize double-stranded DNA directly, showing great potential in nucleic acid detection. However, few studies have investigated the cleavage properties of CRISPR/Cas12a. In this study, the trans-cleavage properties of LbCas12a and AsCas12a were investigated to construct the detection methods for foodborne pathogenic bacteria. The highly sensitive fluorescent strategies for foodborne pathogens were constructed by analyzing the cleavage rates and properties of substrates at different substrate concentrations. Cas12a was activated in the presence of foodborne pathogenic target sequence was present, resulting in the cleavage of a single-stranded reporter ssDNA co-labelled by fluorescein quencher and fluorescein. The sensitivity and specificity of the Cas12a fluorescent strategy was investigated with Salmonella and Staphylococcus aureus as examples. The results showed that AsCas12a was slightly more capable of trans-cleavage than LbCas12a. The detection limits of AsCas12a for Salmonella and Staphylococcus aureus were 24.9 CFU mL-1 and 1.50 CFU mL-1, respectively. In all the seven bacteria, Staphylococcus aureus and Salmonella were accurately discriminated. The study provided a basis for constructing and improving the CRISPR/Cas12a fluorescence strategies. The AsCas12a-based detection strategy is expected to be a promising method for field detection.

Double phage displayed peptides co-targeting-based biosensor with signal enhancement activity for colorimetric detection of Staphylococcus aureus.

The development of simple, fast, sensitive, and specific strategies for the detection of foodborne pathogenic bacteria is crucial for ensuring food safety and promoting human health. Currently, detection methods for Staphylococcus aureus still suffer from issues such as low specificity and low sensitivity. To address this problem, we proposed a sensitivity enhancement strategy based on double phage-displayed peptides (PDPs) co-targeting. Firstly, we screened two PDPs and analyzed their binding mechanisms through fluorescent localization, pull-down assay, and molecular docking. The two PDPs target S. aureus by binding to specific proteins on its outer membrane. Based on this phenomenon, a convenient and sensitive double PDPs colorimetric biosensor was developed. Double thiol-modified phage-displayed peptides (PDP-SH) enhance the aggregation of gold nanoparticles (AuNPs), whereas the specific interaction between the double PDPs and bacteria inhibits the aggregation of AuNPs, resulting in an increased visible color change before and after the addition of bacteria. This one-step colorimetric approach displayed a high sensitivity of 2.35 CFU/mL and a wide detection range from 10-2 × 108 CFU/mL. The combination with smartphone-based image analysis improved the portability of this method. This strategy achieves the straightforward, highly sensitive and portable detection of pathogenic bacteria.

Recent advances in biosynthesis of mycotoxin-degrading enzymes and their applications in food and feed.

Mycotoxins are secondary metabolites produced by fungi in food and feed, which can cause serious health problems. Bioenzymatic degradation is gaining increasing popularity due to its high specificity, gentle degradation conditions, and environmental friendliness. We reviewed recently reported biosynthetic mycotoxin-degrading enzymes, traditional and novel expression systems, enzyme optimization strategies, food and feed applications, safety evaluation of both degrading enzymes and degradation products, and commercialization potentials. Special emphasis is given to the novel expression systems, advanced optimization strategies, and safety considerations for industrial use. Over ten types of recombinases such as oxidoreductase and hydrolase have been studied in the enzymatic hydrolysis of mycotoxins. Besides traditional expression system of Escherichia coli and yeasts, these enzymes can also be expressed in novel systems such as Bacillus subtilis and lactic acid bacteria. To meet the requirements of industrial applications in terms of degradation efficacy and stability, genetic engineering and computational tools are used to optimize enzymatic expression. Currently, registration and technical difficulties have restricted commercial application of mycotoxin-degrading enzymes. To overcome these obstacles, systematic safety evaluation of both biosynthetic enzymes and their degradation products, in-depth understanding of degradation mechanisms and a comprehensive evaluation of their impact on food and feed quality are urgently needed.

Enhanced heat tolerance of freeze-dried Enterococcus faecium NRRL B-2354 as valid Salmonella surrogate in low-moisture foods.

In microbial studies of low-moisture foods (LMFs, water activity less than 0.85), freeze-dried bacteria benefit us to inoculate LMFs without introducing extra water or altering food physiochemical properties. However, the freeze-drying process would bring unavoidable damage to bacterial cells and results in less-resistant inoculum that are unlikely to be qualified in microbial studies. Herein, we enhanced bacterial heat tolerance by subjecting the cells to mild heat (42-50 °C) to counteract the reduced heat tolerance and survivability of freeze-dried bacteria. Enterococcus faecium NRRL B-2354 (E. faecium), a Salmonella surrogate in LMFs, was used as the target microorganism because it was widely accepted in microbial validation of thermal pasteurizing LMFs. Three types of LMFs (peanut powder, protein powder, and onion powder) were used as LMFs models to validate the freeze-dried E. faecium in comparison with Salmonella enterica Enteritidis PT 30 (S. Enteritidis) prepared by the traditional aqueous method. The heat tolerance (D65℃ value) of E. faecium increased at all treatments and peaked (+31.48 ± 0.13%) at temperature-time combinations of 45 °C-60 min and 50 °C-5 min. Survivability of freeze-dried inoculum and its heat tolerance retained well within 50 d storage. The freeze-dried E. faecium was prepared in this study brought equal or higher heat tolerance (D85℃ or D75℃) than S. Enteritidis in tested LMFs models. For instance, the D85℃ of freeze-dried E. faecium (heat-treated at 50 °C for 5 min) and S. Enteritidis in whole egg powder are 35.56 ± 1.52 min and 28.41 ± 0.41 min, respectively. The freeze-dried E. faecium with enhanced heat tolerance appears to be a suitable Salmonella surrogate for dry-inoculating LMFs. Our protocol also enables industry-scale production of freeze-dried inoculum by broth-cultivation method combined with mild-heat treatment.

Exploring the impact of fungal spores from agricultural environments on the mice lung microbiome and metabolic profile.

Exposure to particulate matter (PM) from agricultural environments has been extensively reported to cause respiratory health concerns in both animals and agricultural workers. Furthermore, PM from agricultural environments, containing fungal spores, has emerged as a significant threat to public health and the environment. Despite its potential toxicity, the impact of fungal spores present in PM from agricultural environments on the lung microbiome and metabolic profile is not well understood. To address this gap in knowledge, we developed a mice model of immunodeficiency using cyclophosphamide and subsequently exposed the mice to fungal spores via the trachea. By utilizing metabolomics techniques and 16 S rRNA sequencing, we conducted a comprehensive investigation into the alterations in the lung microbiome and metabolic profile of mice exposed to fungal spores. Our study uncovered significant modifications in both the lung microbiome and metabolic profile post-exposure to fungal spores. Additionally, fungal spore exposure elicited noticeable changes in α and ß diversity, with these microorganisms being closely associated with inflammatory factors. Employing non-targeted metabolomics analysis via GC-TOF-MS, a total of 215 metabolites were identified, among which 42 exhibited significant differences. These metabolites are linked to various metabolic pathways, with amino sugar and nucleotide sugar metabolism, as well as galactose metabolism, standing out as the most notable pathways. Cysteine and methionine metabolism, along with glycine, serine and threonine metabolism, emerged as particularly crucial pathways. Moreover, these metabolites demonstrated a strong correlation with inflammatory factors and exhibited significant associations with microbial production. Overall, our findings suggest that disruptions to the microbiome and metabolome may hold substantial relevance in the mechanism underlying fungal spore-induced lung damage in mice.

Sleep Promotion by 3-Hydroxy-4-Iminobutyric Acid in Walnut Diaphragma juglandis Fructus.

Insufficient sleep can produce a multitude of deleterious repercussions on various domains of human well-being. Concomitantly, the walnut (Juglans mandshurica) confers numerous salutary biological activities pertaining to sleep. Nevertheless, the sedative and hypnotic capacities of walnut's functional constituents remain obscure. In this investigation, we analyzed the sedative and hypnotic components of the walnut Diaphragma juglandis fructus and innovatively discovered a compound, defined as 3-hydroxy-4-iminobutyric acid (HIBA), which disrupts motor activity and enhances sleep duration by regulating the neurotransmitters (GABA, DA, etc.) within the brain and serum of mice. Subsequently, a metabolomics approach of the serum, basal ganglia, hypothalamus, and hippocampus as well as the gut microbiota was undertaken to unravel the underlying molecular mechanisms of sleep promotion. Our data reveal that HIBA can regulate the metabolism of basal ganglia (sphingolipids, acylcarnitines, etc.), possibly in relation to HIBA's influence on the gut microbiome (Muribaculum, Bacteroides, Lactobacillus, etc.). Therefore, we introduce a novel natural product, HIBA, and explicate the modulation of sleep promotion in mice based on the microbiota-gut-brain axis. This study contributes fresh insights toward natural product-based sleep research.

Survival of Listeria monocytogenes and Salmonella in citrus storage waxes or on lemons held under common commercial storage conditions.

To prolong cold storage, diluted storage waxes are applied to washed lemons after harvest and before packing, without drying steps, to reduce premature rotting and water loss. The survival of Listeria monocytogenes and Salmonella in undiluted and diluted storage waxes (S1-S4), and on lemon surfaces under common commercial storage were investigated. Populations of L. monocytogenes declined more slowly than Salmonella in undiluted storage waxes over 24 h of storage at 4 or 22 °C. L. monocytogenes (inoculated at ∼6 log CFU/mL) was detected by enrichment in undiluted waxes S2, S3, and S4 after 75-135 days at 4 °C but not after 30, 10, or 105 days, respectively at 22 °C. L. monocytogenes survived better in diluted than in undiluted storage waxes at 22 °C. Populations of L. monocytogenes (∼6 log CFU/lemon) declined by 0.64-1.62 log on lemon surfaces right after waxing. Populations of L. monocytogenes decreased to <1.30 log CFU/lemon after 28 days (1:9 S1) or 75 days (other treatments) at 12 °C and ≥93% RH. Except for 1:9 S1, L. monocytogenes was detected by enrichment in all lemon samples over 87 days of storage. Packinghouses should consider the survival of L. monocytogenes and Salmonella in citrus storage waxes in their food safety programs.

Metabolic reprogramming of the glutathione biosynthesis modulates the resistance of Salmonella Derby to ceftriaxone.

Salmonella, a foodborne pathogen, has become a major public health concern because of its widespread drug resistance, including resistance to multiple drugs such as third-generation cephalosporin, ceftriaxone (CRO). However, the metabolic profile changes and associated mechanisms engendered by cephalosporin-resistant mutations remain uncharted. In this study, we have employed the LC-MS/MS metabolomics platform to determine the metabolic profiles of 138 strains of Salmonella. Our results show that metabolic profiles correspond to specific serotypes, sources, processing stages, and antibiotic resistance patterns. Notably, we observed that Salmonella Derby (S. Derby) with drug resistance to CRO has a different metabolic status with changes in glutathione biosynthesis. Specifically, glutathione oxidized (GSSG) and citrulline abundances are greatly suppressed in CRO-resistant S. Derby. Furthermore, exogenous GSSG or citrulline, but not glutathione reduced (GSH), restored the susceptibility of multidrug-resistant S. Derby to CRO. This study establishes a strategy based on functional metabolomics to manage the survival of antibiotic-resistant bacteria.

Long-term chronic food-derived arsenic exposure induce the urinary system metabolic dysfunction in mice.

The consumption of rice contaminated with arsenic on a long-term basis has emerged as a pressing public health issue of global significance. Arsenic-induced urinary injury, particularly kidney damage, has received widespread attention. In this study, mice model under long-term arsenic exposure was established, mouse were exposed to rice arsenic (30 mg/kg) for 14 months. Changes of related metabolites were observed based on kidney metabolomics and lipidomics, and major biomarkers were screened by urine metabolomics. The results showed that phosphatidylethanolamine (PE) was significantly increased and phosphatidycholine (PC) and phosphatidylglycerol (PG) were significantly reduced after arsenic exposure, leading to related downstream lipid metabolism disorders. The metabolic pathways for amino acid and energy were observed to be impacted. In addition, metabolic disorders due to arsenic exposure may be associated with inherited neurometabolic disorders, such as D-2-hydroxyglutaric aciduria (D-2-HGA), and pyruvate carboxylase deficiency (PCD), which is predicted based on significant difference biomarkers (2-oxoglutarate, malic acid, and succinic acid) screened for urine. This study elucidates the mechanism of toxicity in the urinary system induced by arsenic exposure at nearly half life cycle, which furnishes crucial scientific evidence pertaining to the toxicity and risk evaluation associated with chronic exposure to the arsenic.

A Simplified Amplification-Free Strategy with Lyophilized CRISPR-CcrRNA System for Drug-Resistant Salmonella Detection.

Drug resistance in pathogenic bacteria has become a major threat to global health. The misuse of antibiotics has increased the number of resistant bacteria in the absence of rapid, accurate, and cost-effective diagnostic tools. Here, an amplification-free CRISPR-Cas12a time-resolved fluorescence immunochromatographic assay (AFC-TRFIA) is used to detect drug-resistant Salmonella. Multi-locus targeting in combination crRNA (CcrRNA) is 27-fold more sensitive than a standalone crRNA system. The lyophilized CRISPR system further simplifies the operation and enables one-pot detection. Induction of nucleic acid fixation via differentially charged interactions reduced the time and cost required for flowmetric chromatography with enhanced stability. The induction of nucleic acid fixation via differentially charged interactions reduces the time and cost required for flowmetric chromatography with enhanced stability. The platform developed for the detection of drug-resistant Salmonella has an ultra-sensitive detection limit of 84 CFU mL-1 within 30 min, with good linearity in the range of 102 -106 CFU mL-1 . In real-world applications, spiked recoveries range from 76.22% to 145.91%, with a coefficient of variation less than 10.59%. AFC-TRFIA offers a cost-effective, sensitive, and virtually equipment-independent platform for preventing foodborne illnesses, screening for drug-resistant Salmonella, and guiding clinical use.

Formation of Listeria monocytogenes persister cells in the produce-processing environment.

Persisters are a subpopulation of growth-arrested cells that possess transient tolerance to lethal doses of antibiotics and can revert to an active state under the right conditions. Persister cells are considered as a public health concern. This study examined the formation of persisters by Listeria monocytogenes (LM) in an environment simulating a processing plant for leafy green production. Three LM strains isolated from California produce-processing plants and packinghouses with the strongest adherence abilities were used for this study. The impact of the cells' physiological status, density, and nutrient availability on the formation of persisters was also determined. Gentamicin at a dose of 100 mg/L was used for the isolation and screening of LM persisters. Results showed that the physiological status differences brought by culture preparation methods (plate-grown vs. broth-grown) did not impact persister formation (P > 0.05). Instead, higher persister ratios were found when cell density increased (P < 0.05). The formation of LM persister cells under simulated packinghouse conditions was tested by artificially inoculating stainless steel coupons with LM suspending in media with decreasing nutrient levels: brain heart infusion broth (1366 mg/L O2), produce-washing water with various organic loads (1332 mg/L O2 and 652 mg/L O2, respectively), as well as sterile Milli-Q water. LM survived in all suspensions at 4 °C with 85 % relative humidity for 7 days, with strain 483 producing the most persister cells (4.36 ± 0.294 Log CFU/coupon) on average. Although persister cell levels of LM 480 and 485 were reasonably steady in nutrient-rich media (i.e., BHI and HCOD), they declined in nutrient-poor media (i.e., LCOD and sterile Milli-Q water) over time. Persister populations decreased along with total viable cells, demonstrating the impact of available nutrients on the formation of persisters. The chlorine sensitivity of LM persister cells was evaluated and compared with regular LM cells. Results showed that, despite their increased tolerance to the antibiotic gentamicin, LM persisters were more susceptible to chlorine treatments (100 mg/L for 2 min) than regular cells.

Metabolic pathway-based self-assembled Au@MXene liver microsome electrochemical biosensor for rapid screening of aflatoxin B1.

Cytochrome P450 enzymes (CYPs) catalyze the production of aflatoxin B1 (AFB1) metabolites, which play an important role in carcinogenesis. In this study, we report a simple electrochemical liver-microsome-based biosensor using a composite of gold nanoparticles adsorbed on MXene (Au@MXene) for rapid screening of AFB1. Rat liver microsomes (RLMs) were directly adsorbed on the Au@MXene nanocomposite. The high conductivity, large specific surface area, and good biocompatibility of the Au@MXene nanocomposite enabled the direct electron transfer between the RLMs and the electrode and maintained the biological activity of the enzyme in the RLMs to a large extent. The metabolic behavior of the RLM biosensor that was developed for the electrocatalyst of AFB1 to its hydroxylation metabolite aflatoxin M1 (AFM1) was confirmed. Based on the change in the electrical signal generated by this metabolic behavior, we established the relationship between AFB1 content and amperometric (I-t) current signal. When the AFB1 concentration ranged from 0.01 µM to 50 µM, the AFB1 concentration was linearly related to the electrical signal with a limit of detection of 2.8 nM. The results of the recovery experiments for corn samples showed that the recovery and accuracy of the sensor were consistent with the UPLC-MS/MS method.

Approaches for a more microbiologically and chemically safe dried fruit supply chain.

Global production of dried fruits has increased significantly in the past decade. Both the increased consumer acceptance of nutritious packaged food and the broad use of dried fruits in products such as confectionery and bakery goods have fueled the dried fruit demand. Unfortunately, outbreaks and recalls due to contamination by pathogenic bacteria and viruses as well as the detection of mycotoxins highlight the need for optimizing current approaches, and evaluating and adopting newer interventions to protect the microbial and chemical safety of dried fruits. Drying processes alone are inadequate to control these hazards. Pre- and post-drying treatments serve as promising opportunities, with or without combination with the drying step, to achieve the goals of efficient hazard control.

Efficient Biodegradation of Patulin by Aspergillus niger FS10 and Metabolic Response of Degrading Strain.

Patulin, a mycotoxin commonly found in fruits and derived products, causes serious health problems for humans and animals worldwide. Several microbial strains have been observed to possess the ability to effectively remove patulin. However, these methods are presently associated with disadvantages such as low degradation efficiency and an unclear biodegradation mechanism. In the current study, the characteristics of patulin degradation via Aspergillus niger FS10 were evaluated, and the mechanisms involved were analyzed using metabolomics technologies. The results showed that the suspension of A. niger FS10 could degrade 94.72% of patulin within 36 h. The moment concentration pf patulin was 0.116 µg/mL, and the detection limit value was 0.01 µg/mL. In addition, the patulin content was reduced to levels below the detection limit within 48 h. A. niger FS10 mainly degrades patulin by producing intracellular enzymes, which can convert patulin into ascladiol. This degradation method can effectively reduce the damage caused by patulin to HepG2 cells. In addition, the patulin treatment significantly affects the pentose phosphate pathway and the glutathione pathway. These two metabolic pathways are speculated to be closely related to patulin degradation via A. niger FS10. The incubation of A. niger FS10 with patulin-contaminated apple pomace can not only eliminate patulin but also increase the utilization of apple pomace. Therefore, our research results provide a new method for addressing patulin contamination in the food and feed industries.

Carbon dots cooperatively modulating photocatalytic performance and surface charge of O-doped g-C3N4 for efficient water disinfection.

The emergence of widespread microbial contamination and drug-resistant bacteria in the water environment poses a severe threat to public health. Photocatalysis is considered an efficient, energy-saving, and cost-effective disinfection strategy for effectively removing microbial contamination from water bodies. In this paper, a metal-free O-doped g-C3N4/carbon dots (O-CN/CDs) nanosheet photocatalysts are prepared in coordination with various modification strategies, which results in a considerable improvement in photocatalytic disinfection activity compared to bulk g-C3N4 (B-CN). First, O-doping and morphology modulation are achieved simultaneously with hydrothermal treatment, which not only hinders the recombination of photogenerated hole-electron pairs, but also enables the exposure of more active centers. Subsequently, loading of CDs onto O-CN nanosheets by electrostatic self-assembly increases the production of photogenerated hole-electron pairs by expanding the visible light absorption region and promoted the separation of photogenerated carriers by trapping photogenerated electrons. Interestingly, the loading of CDs changes the charge on the surface of the composite photocatalyst from negative to positive, making it easier for the active species to come in contact with bacteria, and thus improving bacterial disinfection performance. Under visible light irradiation, the inactivation efficiency of optimized O-CN/CDs against methicillin-resistant Staphylococcus aureus (MRSA) is log(C/C0) = 4.08, approximately 9 times higher than that of B-CN. The main active species inactivating bacteria are superoxide anions radicals (•O2-) and photogenerated holes, and their attack causes damage to the membrane wall structure and leakage of intracellular components. Additionally, the feasibility of the as-prepared photocatalysts in water disinfection in real environments was confirmed by photocatalytic disinfection experiments in successive recovery cycles and in practical lake water.

Volatile Metabolite Profiling of Wheat Kernels Contaminated by Fusarium graminearum.

Traditional methods used to detect fungi or mycotoxins are time-consuming and prevent real-time monitoring. In this study, solid-phase microextraction combined with full two-dimensional gas chromatography time-of-flight mass spectrometry was utilized to detect volatile organic compounds (VOCs) produced by fungi during grain infestation predictive F. graminearum PH-1 infestation in wheat. The results show that the VOCs emitted by F. graminearum can distinguish strains at different growth stages. The growth matrices (potato dextrose agar medium and wheat kernels) play a large role in VOC production. The infection of wheat sample F. graminearum showed that a specific relationship between VOCs and the composition of fungal flora, for example, 5-pentyl-cyclohexa-1,3-diene, 3-hexanone, and 1,3-octadiene, was positively correlated with the infection rate of PH-1. In the correlation study of fungal mycotoxins and VOCs, zearalenone produced by F. graminearum was predicted based on the VOCs released. Further analysis determined the correlation of three VOCs, 6-butyl-1,4-cycloheptadiene, hexahydro-3-methylenebenzofuran-2(3H)-one, and (E,E)-3,5-octadien-2-one, with zearalenone production, confirming the ability of VOCs as characteristic markers of mycotoxins.