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Salmonella enteritidis (SE) is a food-borne pathogens that can cause acute gastroenteritis. With the increasing social attention to food safety, the detection method of SE has attracted wide attention. In response to the demand for efficient detection methods of SE, this study constructed a novel dual-mode photoelectrochemical-electrochemical (PEC-EC) aptamer-based biosensor. The sensor was constructed using Bi4NbO8Cl/In2S3 heterojunction as the electrode substrate material, the hybridization chain reaction (HCR) and dye sensitization were used as the signal amplification strategies. Bi4NbO8Cl/In2S3 heterojunction could provide an excellent initial photocurrent response for the sensing platform, and the HCR was opened by the end of complementary DNA (cDNA) and generated an ultra-long DNA double-stranded (dsDNA) "super structure" on the surface of the electrode, which could be embedded with a large number of methylene blue (MB) as the bifunctional probes. Thus, dual-mode output was achieved via the PEC and EC activity of MB. Under the optimized conditions, the PEC and EC signal responses of the system were linear to the logarithm of SE concentration in a range from 1.5 × 102 CFU/mL to 1.5 × 107 CFU/mL. The detection limits were found to be 12.9 CFU/mL and 12.3 CFU/mL using the PEC and EC methods, respectively. The constructed dual-mode biosensor exhibited good performance for real sample analysis, and demonstrated great application potential in the field of SE rapid detection. Moreover, this dual-mode detection strategy provided more accurate and reliable results than the single-mode output.
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Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Técnicas Eletroquímicas , Ouro , Salmonella enteritidis , Salmonella enteritidis/isolamento & purificação , Aptâmeros de Nucleotídeos/química , Técnicas Eletroquímicas/métodos , Técnicas Biossensoriais/métodos , Ouro/química , Processos Fotoquímicos , Eletrodos , Limite de Detecção , Bismuto/química , Sulfetos/química , Azul de Metileno/químicaRESUMO
Hafnia alvei is a spoilage microorganism that possesses the LuxI/LuxR-type quorum sensing (QS) system. Biogenic amines (BAs) are important in food spoilage and safety, yet the role of QS in BA formation remains poorly understood. This study investigated the ability of H. alvei H4 to produce BAs in fish flesh and decarboxylase culture media. The findings showed that H. alvei H4 produced substantial amounts of putrescine and cadaverine in turbot flesh, with its enhanced amine-producing capacity potentially leading to the eventual deterioration of the fish. Furthermore, the deletion of the QS element-AHL synthase gene luxI-affected the concentrations of both BAs. Based on these observations, the present study conducted multifaceted experiments, including phenotypic assessments and analyses of gene expression, to explore the role of luxI and to identify its specific binding targets. The results indicated that putrescine formation in H. alvei H4 primarily occurred via the arginine deiminase (ADI) pathway, with luxI playing a positive role in the conversion of arginine to ornithine and subsequently to putrescine. The reduction in putrescine content observed in a luxI mutant (ΔluxI) was attributed to the direct binding of the LuxI protein to the promoters of the argF and speC genes, which code for ornithine carbamoyltransferase and ornithine decarboxylase, respectively. The findings of this study provided the basis to understand the influence of QS on BA production in H. alvei, by specifically demonstrating the involvement of the luxI gene on putrescine and cadaverine production.
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Proteínas de Bactérias , Aminas Biogênicas , Cadaverina , Hafnia alvei , Putrescina , Aminas Biogênicas/metabolismo , Putrescina/metabolismo , Animais , Cadaverina/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Hafnia alvei/metabolismo , Hafnia alvei/genética , Regulação Bacteriana da Expressão Gênica , Percepção de Quorum , Linguados/metabolismo , Microbiologia de AlimentosRESUMO
Monitoring food freshness is considerably important for food safety. In this study, a smart pH-responsive fluorescence hydroxypropyl methyl cellulose-κ-carrageenan-fluorescein isothiocyanate-NH2-CaAl2O4 (H-K-F-N) film was prepared. Taking synergetic advantage of the pH-dependent behavior of fluorescein isothiocyanate dye and the luminescence characteristics of calcium aluminate phosphor, the film exhibited a unique strong pH-responsive fluorescence with an exceptional linear relationship (correlation coefficient, R2 = 0.9993) across a wide pH rang of 2.0-12.0. Moreover, the H-K-F-N film, as a smart sensor, could be used to estimate the total volatile basic nitrogen and total viable count through fluorescence intensity based on the partial least squares regression model and support vector machine regression, respectively. Leveraging the relationship between the fluorescent image's digital signals and food freshness indicators, a smartphone-assisted system was developed. These results demonstrated that H-K-F-N film is promising for applications in intelligent food packaging and food safety monitoring.
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Single center studies are limited by bias, lack of generalizability and variability, and inability to study rare conditions. Multicenter observational research could address many of those concerns, especially in hand surgery where multicenter research is currently quite limited; however, there are numerous barriers including regulatory issues, lack of common terminology, and variable data set structures. The Observational Health Data Sciences and Informatics (OHDSI) program aims to surmount these limitations by enabling large-scale, collaborative research across multiple institutions. The OHDSI uses the Observational Medical Outcomes Partnership (OMOP) Common Data Model (CDM) to standardize health care data into a common language, enabling consistent and reliable analysis. The OMOP CDM has been transformative in converting multiple databases into a standardized code with a single vocabulary, allowing for coherent analysis across multiple data sets. Building upon the OMOP CDM, OHDSI provides an extensive suite of open-source tools for all research stages, from data extraction to statistical modeling. By keeping sensitive data local and only sharing summary statistics, OHDSI ensures compliance with privacy regulations while allowing for large-scale analyses. For hand surgery, OHDSI can enhance research depth, understanding of outcomes, risk factors, complications, and device performance, ultimately leading to better patient care.
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Self-powered photoelectrochemical (PEC) sensing is a novel sensing modality. The introduction of dual-mode sensing and photoelectrocatalysis in a self-powered system enables both detection and sterilization purposes. To this end, herein, a self-powered multifunctional platform for the photoelectrochemical-fluorescence (PEC-FL) detection and in-situ inactivation of Salmonella enteritidis (SE) was constructed. The platform utilized Bi4NbO8Cl/V2CTx/FTO as a photoanode and CuInS2/FTO as a photocathode and incubated quantum dot (QDs) signaling probes on the surface of the photocathode. During detection, the system drives the transfer of photogenerated electrons between the dual photoelectrodes through the Fermi energy level difference. The photoanode amplifies the photoelectric signal, while the photocathode is solely dedicated to the immune recognition process. QDs provide an additional fluorescence signal to the system. Under optimal experimental conditions, the multifunctional platform achieves detection limits of 3.2 and 5.3 CFU/mL in PEC and FL modes respectively, with a detection range of 2.91 × 102 to 2.91 × 108 CFU/mL. With the application of an external bias voltage, it further promotes electron transfer between the dual photoelectrodes, inhibits the recombination of photogenerated electrons and holes. It generates a significant amount of superoxide radicals (·O2-) in the cathodic region, resulting in strong sterilization efficiency (99%). The constructed self-powered multifunctional platform exhibits high sensitivity and sterilization efficiency, it provides a feasible and effective strategy to enhance the comprehensive capability of self-powered sensors.
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Técnicas Biossensoriais , Técnicas Eletroquímicas , Pontos Quânticos , Salmonella enteritidis , Salmonella enteritidis/isolamento & purificação , Pontos Quânticos/química , Técnicas Biossensoriais/instrumentação , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Limite de Detecção , Eletrodos , Humanos , Infecções por Salmonella/microbiologiaRESUMO
In this study, the active food packaging film were prepared using hydroxypropyltrimethyl ammonium chloride chitosan with different substitution sites (O-HACC & N-HACC) and dialdehyde chitosan (DCS) grafted with protocatechuic acid (PA). To explore the effect of chitosan quaternization positions and crosslinking approaches on the slow-release and antibacterial properties, the double-crosslinked film were fabricated through the self-coupling reaction of PA and Schiff base reaction between amino groups on HACC and aldehyde groups on DCS. The HACC/DCS-based film exhibited stable porous three-dimensional networks with high nisin loading ratios (>90 %). With the participation of the catechol-catechol structure, the dense double-crosslinked film effectively restricted the diffusion of the water molecules, resulting in excellent slow-release properties fitting with the Korsmeyer-Peppas kinetic model. Especially, O-HACC/PA-g-DCS film, which had more reaction sites for Schiff base crosslinking than N-HACC, exhibited the equilibrium swelling ratio of 800 % at 60 h and could sustainably release nisin via non-Fickian diffusion behavior until 48 h. Moreover, the HACC/DCS-based double-crosslinked film performed good long-time antibacterial activity and preservation effects on salmon. On the 10th day of storage, the TVBN of N-HACC/PA-g-DCS and O-HACC/PA-g-DCS groups were only 28.26 ± 1.93 and 29.06 ± 1.68 mg/100 g and still lower than the thresholds.
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Antibacterianos , Quitosana , Compostos de Amônio Quaternário , Quitosana/química , Quitosana/análogos & derivados , Antibacterianos/farmacologia , Antibacterianos/química , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/farmacologia , Embalagem de Alimentos/métodos , Nisina/química , Nisina/farmacologia , Preparações de Ação Retardada , Hidroxibenzoatos/química , Hidroxibenzoatos/farmacologia , Cinética , Bases de Schiff/química , Liberação Controlada de Fármacos , Testes de Sensibilidade Microbiana , Staphylococcus aureus/efeitos dos fármacosRESUMO
In recent years, piezo-photocatalysis has become a promising strategy for solving environmental pollution problems by adding additional mechanical energy to the photocatalysis process. This work reported the effective synthesis of a variety of HKUST-1/BiVO4 heterogeneous materials by combining monoclinic BiVO4 and porous HKUST-1 semiconductors. The piezo-photocatalytic properties of HKUST-1/BiVO4 were studied by the reduction of hexavalent chromium (Cr(VI)) under visible-light irradiation and ultrasonic waves. In the piezo-photocatalysis process, the best reduction rates among as-prepared HKUST-1/BiVO4 composites were up to 96.20% of 10 ppm Cr(VI) solution, which was approximately 1.80 times that under visible light and about 4.13 times that under ultrasound. Under the action of the piezoelectric potential, the availability of free radicals increased the reduction rate of Cr(VI) and reached a synergistic effect of 1.14-fold.
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Optimizing nitrogen removal is crucial for ensuring the efficient operation of wastewater treatment plants (WWTPs), but it is susceptible to variations in influent conditions and operational parameter constraints, and conflicts with the energy-saving and carbon emission reduction goals. To address these issues, this study proposes a hybrid framework integrating process simulation, machine learning, and multi-objective genetic algorithms for nitrogen removal diagnosis and optimization, aiming to predict the total nitrogen in effluent, diagnose nitrogen over-limit risks, and optimize the control strategies. Taking a full-scale WWTP as a case study, a process time-lag simulation-enhanced machine learning model (PTLS-ML) was developed, achieving R2 values of 0.94 and 0.79 for the training and testing sets, respectively. The proposed model successfully identified the potential reasons of nitrogen over-limit risks under different influent conditions and operational parameters, and accordingly provided optimization suggestions. In addition, the multi-objective optimization (MOO) algorithms analysis further demonstrated that maintaining 4-6 mg/L total nitrogen concentration in effluent by adjusting process operational parameters can effectively balance multiple objectives (i.e., effluent water quality, operating costs, and greenhouse gas emissions), achieving coordinated optimization. This framework can serve as a reference for stable operation, energy-saving, and emission reduction in the nitrogen removal of WWTPs.
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The aim of our study was to investigate whether the combination of benzyl isothiocyanate (BITC) and resveratrol (RES) has a synergistic effect on the inhibition of inflammation in colitis. The results revealed that the BITC and RES combination (BITC_RES) was more effective than either substance alone at significantly alleviating the symptoms of dextran sodium sulfate (DSS)-induced colitis in mice, including the prevention of colon shortening and loss of body weight, a reduction in the disease activity index, and prevention of colon damage. Similarly, compared with the DSS group, BITC_RES reduced myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) levels in the mouse colon by 1.4-3.0-fold and 1.4-fold, respectively. In addition, the combination of BITC and RES upregulated the inflammatory factor IL-10 by 1.3- and 107.4-fold, respectively, compared to the individual BITC and RES groups, whereas the proinflammatory factors, including TNF-α, IL-1ß, and IL-6, were downregulated by 1.1-7.4-, 0.7-3.6-, and 0.6-2.6-fold, respectively, in the BITC_RES group compared with the individual groups. Gut microbiome analysis indicated that BITC_RES remodeled the structure of gut bacteria at the phylum, family, and genus levels, upregulating the abundance of the phylum Bacteroidetes and the family Muribaculaceae and the genus norank_f_Muribaculaceae and downregulating the abundance of the phylum Firmicutes. Significant correlations between the relative levels of these proinflammatory cytokines and changes in the gut microbiota were found using Pearson's correlation analysis. BITC and RES exhibited synergistic effects by reshaping the gut microbiota and modulating the level of serum cellular inflammatory factors, thus exerting a protective effect against colitis.
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Benzyl isothiocyanate (BITC) is a naturally active bacteriostatic substance and κ-carrageenan (KC) is a good film-forming substrate. In the present study, a nanoemulsion incorporating BITC was fabricated with a particle size of 224.1 nm and an encapsulation efficiency of 69.2 %. Subsequently, the acquired BITC nanoemulsion (BITC-NE) was incorporated into the KC-based film, and the light transmittance of the prepared composite films was lower than that of the pure KC film. Fourier transform infrared spectroscopy and scanning electron microscopy revealed that BITC-NE was compatible with the KC matrix. BITC-NE incorporation enhanced the tensile strength of the KC-based films by 33.7 %, decreased the elongation at break by 33.8 %, decreased the water vapor permeability by 60.1 %, increased the maximum thermal degradation temperature by 48.8 %, and decreased the oxygen permeability by 42 % (p < 0.05). Furthermore, the composite films showed enhanced antimicrobial activity against Staphylococcus aureus, Salmonella typhimurium, and Pseudomonas fluorescens. The developed KC-based composite films were applied to wrap raw beef, which significantly delayed the increase in total viable count, total volatile base nitrogen content, and thiobarbituric acid reactive substances, and prolonged the shelf-life of the raw beef by up to 10 days. These results indicated that the composite films prepared by incorporating BITC nanoemulsions into KC matrices have great antimicrobial application potential.
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Antibacterianos , Carragenina , Emulsões , Isotiocianatos , Carragenina/química , Carragenina/farmacologia , Isotiocianatos/química , Isotiocianatos/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Animais , Permeabilidade , Conservação de Alimentos/métodos , Bovinos , Carne Vermelha , Embalagem de Alimentos/métodos , Testes de Sensibilidade Microbiana , Espectroscopia de Infravermelho com Transformada de Fourier , Resistência à TraçãoRESUMO
Introduction: Affective decision-making is a prominent topic in consumer psychology research, with its core assumption being that consumers tend to purchase brands and commodities they like. However, the reasons behind why we develop emotional responses of liking or disliking toward certain commodities, as well as what the underlying neural mechanisms are, remain largely unknown. Methods: This study utilized the S1-S2 paradigm in an experiment wherein S1 presented 12 types of commodities and S2 displayed 48 distinct colored squares. Participants were instructed to assess whether they "Like" or "Dislike" the commodity in S1, which was colored with the S2 color. Electroencephalogram (EEG) recordings were obtained during the reaction process and subsequently analyzed to examine the components of S2-induced event-related potentials (ERPs). Results: The analysis revealed that S2 elicited a significant N270 in the prefrontal scalp area under both the "Like" and "Dislike" conditions. Interestingly, the amplitude of the N270 was significantly higher during the "Dislike" condition compared to the "Like" condition. Discussion: The N270 component was shown to reflect the conflict in physical attributes between S1 and S2, as well as the conflict between commodity and color. This highlights the potential utility of this component as an objective EEG indicator of consumer commodity color preferences in future marketing research.
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Staphylococcus aureus (S. aureus) is a common pathogen that can cause many serious infections. Thus, efficient and practical techniques to fight S. aureus are required. In this study, transcriptomics was used to evaluate changes in S. aureus following treatment with benzyl isothiocyanate (BITC) to determine its antibacterial action. The results revealed that the BITC at subinhibitory concentrations (1/8th MIC) treated group had 94 differentially expressed genes compared to the control group, with 52 downregulated genes. Moreover, STRING analyses were used to reveal the protein interactions encoded by 36 genes. Then, we verified three significant virulence genes by qRT-PCR, including capsular polysaccharide synthesis enzyme (cp8F), capsular polysaccharide biosynthesis protein (cp5D), and thermonuclease (nuc). Furthermore, molecular docking analysis was performed to investigate the action site of BITC with the encoded proteins of cp8F, cp5D, and nuc. The results showed that the docking fraction of BITC with selected proteins ranged from - 6.00 to - 6.60 kcal/mol, predicting the stability of these complexes. BITC forms hydrophobic, hydrogen-bonded, π-π conjugated interactions with amino acids TRP (130), GLY (10), ILE (406), LYS (368), TYR (192), and ARG (114) of these proteins. These findings will aid future research into the antibacterial effects of BITC against S. aureus.
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Heterocyclic aromatic amines (HAAs), arising as chemical derivatives during the high-temperature culinary treatment of proteinaceous comestibles, exhibit notable carcinogenic potential. In this paper, a composite aerogel (AGD-UiO-66) with high-capacity and fast adsorption of HAAs was made with anchoring defective UiO-66 (D-UiO-66) mediated by lauric acid on the backbone of cellulose nanofibers (CNF). AGD-UiO-66 with hierarchical porosity reduced the mass transfer efficiency for the adsorption of HAAs and achieved high adsorption amount (0.84-1.05 µmol/g) and fast adsorption (15 min). The isothermal adsorption model demonstrated that AGD-UiO-66 belonged to a multilayer adsorption mechanism for HAAs. Furthermore, AGD-UiO-66 was successfully used to adsorb 12 HAAs in different food (roasted beef, roasted pork, roasted salmon and marinade) with high recoveries of 94.65%-104.43%. The intrinsic potential of AGD-UiO-66 demonstrated that it could be widely applicable to the adsorption of HAAs in foods.
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Aminas , Celulose , Nanocompostos , Adsorção , Aminas/química , Celulose/química , Animais , Nanocompostos/química , Compostos Heterocíclicos/química , Bovinos , Suínos , Salmão , Estruturas Metalorgânicas/química , Carne/análise , Contaminação de Alimentos/análise , Géis/químicaRESUMO
Heterocyclic aromatic amines (HAAs) are the main carcinogens produced during thermal processing of protein-rich foods. In this paper, a composite aerogel (TOCNFCa) with a stabilized dual-network structure was prepared via a template for the in-situ synthesis of UiO-66 on cellulose for the adsorption of HAAs in food. The dual-network structure of TOCNFCa provides the composite aerogel with excellent wet strength, maintaining excellent compressive properties. With the in-situ grown UiO-66 content up to 71.89 wt%, the hierarchical porosity endowed TOCNFCa@UiO-66 with the ability to rapidly adsorb HAAs molecules with high capacity (1.44-5.82 µmol/g). Based on excellent thermal stability, adsorption capacity and anti-interference, TOCNFCa@UiO-66 achieved satisfactory recoveries of HAAs in the boiled marinade, which is faster and more economical than the conventional SPE method. Moreover, TOCNFCa@UiO-66 could maintain 84.55 % of the initial adsorption capacity after 5 times of reuse.
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Aminas , Celulose , Compostos Heterocíclicos , Estruturas Metalorgânicas , Nanofibras , Ácidos Ftálicos , Celulose/química , Adsorção , Aminas/química , Nanofibras/química , Estruturas Metalorgânicas/química , Compostos Heterocíclicos/química , Géis/química , PorosidadeRESUMO
The objective of this study was to examine the intervention effect of group sensory integration training on social responsiveness, and the latency and amplitude of N170 event-related potential of children with autism. The social responsiveness scale was employed to assess alterations in the social response of individuals with ASD before and after training, while event-related potentials were utilized to measure changes in N170 latency and amplitude. This study revealed that group sensory integration training can significantly enhance social responsiveness in children diagnosed with ASD. Children with ASD exhibit atypical N170 responses to faces in the right parietal region. The latency of N170 changes may serve as a valuable indicator for assessing the effectiveness of an intervention or diagnosing ASD.
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Hafnia alvei, a specific spoilage microorganism, has a strong capacity to destroy food protein and lead to spoilage. The aim of this study was to evaluate the phase-dependent regulation of lux-type genes on the spoilage characteristics of H. alvei H4. The auto-inducer synthase gene luxI and a regulatory gene luxR of the quorum sensing systems in H. alvei H4 were knocked out to construct the mutant phenotypes. On this basis, the research found that the luxI and luxR genes had a strong positive influence on not only flagella-dependent swimming ability and biofilm formation but also the production of putrescine and cadaverine. The luxR gene could downregulate putrescine production. The maximum accumulation of putrescine in wild type, ΔluxI, ΔluxR and ΔluxIR were detected at 24 h, reaching up to 695.23 mg/L, 683.02 mg/L, 776.30 mg/L and 724.12 mg/L, respectively. However, the luxI and luxR genes have a potential positive impact on the production of cadaverine. The maximum concentration of cadaverine produced by wild type, ΔluxI, ΔluxR and ΔluxIR were 252.7 mg/L, 194.5 mg/L, 175.1 mg/L and 154.2 mg/L at 72 h. Moreover, the self-organizing map analysis revealed the phase-dependent effects of two genes on spoilage properties. The luxI gene played a major role in the lag phase, while the luxR gene mainly acted in the exponential and stationary phases. Therefore, the paper provides valuable insights into the spoilage mechanisms of H. alvei H4.
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Importance: The No Surprises Act implemented in 2022 aims to protect patients from surprise out-of-network (OON) bills, but it does not include ground ambulance services. Understanding ground ambulance OON and balance billing patterns from previous years could guide legislation aimed to protect patients following ground ambulance use. Objective: To characterize OON billing from ground ambulance services by evaluating whether OON billing risk differs by the site of ambulance origination (home, hospital, nonhospital medical facility, or scene of incident). Design, Setting, and Participants: Cross-sectional study of the Merative MarketScan dataset between January 1, 2015, and December 31, 2020, using claims-based data from employer-based private health insurance plans in the US. Participants included patients who utilized ground ambulances during the study period. Data were analyzed from June to December 2023. Exposure: Medical encounter requiring ground ambulance transportation. Main Outcomes and Measures: Ground ambulance OON billing prevalence was calcuated. Linear probability models adjusted for state-level mixed effects were fit to evaluate OON billing probability across ambulance origins. Secondary outcomes included the allowed payment, patient cost-sharing amounts, and potential balance bills for OON ambulances. Results: Among 2â¯031â¯937 ground ambulance services (1â¯375â¯977 unique patients) meeting the inclusion and exclusion criteria, 1â¯072â¯791 (52.8%) rides transported men, and the mean (SD) patient age was 41 (18) years. Of all services, 1â¯113â¯676 (54.8%) were billed OON. OON billing probabilities for ambulances originating from home or scene were higher by 12.0 percentage points (PP) (95% CI, 11.8-12.2 PP; P < .001 for home; 95% CI, 11.7-12.2 PP; P < .001 for scene) vs those originating from hospitals. Mean (SD) total financial burden, including cost-sharing and potential balance bills per ambulance service, was $434.70 ($415.99) per service billed OON vs $132.21 ($244.92) per service billed in-network. Conclusions and Relevance: In this cross-sectional study of over 2 million ground ambulance services, ambulances originating from home, the scene of an incident, and nonhospital medical facilities were more likely to result in OON bills. Legislation is needed to protect patients from surprise billing following use of ground ambulances, more than half of which resulted in OON billing. Future legislation should at minimum offer protections for these subsets of patients often calling for an ambulance in urgent or emergent situations.
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Ambulâncias , Custo Compartilhado de Seguro , Masculino , Humanos , Adulto , Estudos Transversais , Estresse Financeiro , Instalações de SaúdeRESUMO
Quorum sensing (QS) regulation of functional metabolites is rarely reported but a common trait of some bacteria. In this study, we found that QS promoted the extracellular accumulation of glycine and serine while inhibiting the extracellular accumulation of methionine in Hafnia alvei H4. The correlation analysis of five QS signals with the above three QS-regulated amino acids suggested that these QS signals may have functional differences in amino acid regulation. The exogenous AHL add-back studies on genes involved in glycine, serine, and methionine metabolic pathway highlighted that N-octanoyl-l-homoserine lactone (C8-HSL) downregulated the expression of sdhC/fumA genes involved in the succinate to malate pathway, thereby reducing the metabolic flux of the tricarboxylic acid (TCA) cycle as an amino acid metabolism platform. Further in-depth research revealed that the QS system promoted the conversion of folate to tetrahydrofolate (THF) by positively regulating the expression of folA and folM, thus impairing the ability of folate to promote methionine accumulation. Moreover, folate positively regulated the expression of the QS signal synthesis gene luxI, promoting the synthesis of QS signals, which may further enhance the influence of the QS system on amino acid metabolism. These findings contribute to the understanding of amino acid metabolism regulated by QS and provide new perspectives for accurate control of metabolic regulation caused by QS.IMPORTANCEAs one of the important regulatory mechanisms of microorganisms, quorum sensing (QS) is involved in the regulation of various physiological activities. However, few studies on the regulation of amino acid metabolism by QS are available. This study demonstrated that the LuxI-type QS system of Hafnia alvei H4 was involved in the regulation of multiple amino acid metabolism, and different types of QS signals exhibited different roles in regulating amino acid metabolism. Additionally, the regulatory effects of the QS system on amino acid metabolism were investigated from two important cycles that influence the conversion of amino acids, including the TCA cycle and the folate cycle. These findings provide new ideas on the role of QS system in the regulation of amino acid metabolism in organisms.
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Hafnia alvei , Percepção de Quorum , Percepção de Quorum/fisiologia , Aminoácidos , Metionina , Glicina , Ácido Fólico , SerinaRESUMO
In the food industry, foodborne spoilage bacteria often live in mixed species and attach to each other, leading to changes in spoilage characteristics. Quorum sensing (QS) has been reported to be a regulating mechanism for food spoiling by certain kinds of bacteria. Here, the contents of biofilm, extracellular polysaccharides, and biogenic amines in the coculture system of Hafnia alvei H4 and Pseudomonas fluorescens ATCC13525 were significantly reduced when the QS element of H. alvei H4 was deleted, confirming that QS of H. alvei H4 is involved in the dual-species interactions. Then, transcriptomics was used to explore the regulatory mechanism at the mRNA molecular level. The deletion of the QS element decreased the transcript levels of genes related to chemotaxis, flagellar assembly, and the two-component system pathway of H. alvei H4 in the coculture system. Furthermore, a total of 732 DEGs of P. fluorescens ATCC13525 were regulated in the dual species, which were primarily concerned with biofilm formation, ATP-binding cassette transporters, and amino acid metabolism. Taken together, the absence of the QS element of H. alvei H4 weakened the mutual cooperation of the two bacteria in the coculture system, making it a good target for managing infection with H. alvei and P. fluorescens.
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Composite aerogels, formed by the combination of nanoscale polymers and highly efficient adsorbents, offer the potential to deploy adsorbent distinct separation properties into a processable matrix. This paper presents a method for the fabrication of low energy bio-aerogels with high ductility, excellent wet strength and favorable heat resistance, based on cellulose nanofibers (CNFs) bound by calcium carbonate particles (CaCO3) via a simple process of ice induction, cross-linking during freezing and freeze-drying. Due to induced defects, two-dimensional metal-organic layers (MOLs) were rich in mesoporous structure and embedded in the aerogel (AGCa-MOL), which exhibited a powerful adsorption capacity. AGCa-MOL could take full advantage of their hierarchical pores and available surface area to obtain high adsorption capacity (0.694-5.470 µmol/g) and rapid adsorption kinetics (5 min) for 14 heterocyclic aromatic amines (HAAs). Moreover, the CaCO3 particles and MOLs gave the AGCa-MOL excellent thermal stability, so that it could maintain excellent adsorption capacity at a high temperature (100 °C) and be applied as an adsorbent to remove HAAs in the boiling marinade. The intrinsic potential of composite aerogels was revealed due to the synergistic properties of the various components in the composite aerogel.