RESUMO
Rapid screening for foodborne pathogens is crucial for food safety. A rapid and one-step electrochemical sensor has been developed for the detection of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Salmonella typhimurium (S. typhimurium). Through the construction of aptamer/two-dimensional carboxylated Ti3C2Tx (2D C-Ti3C2Tx)/two-dimensional Zn-MOF (2D Zn-MOF) composites, the recognition elements, signal tags, and signal amplifiers are integrated on the electrode surface. Pathogens are selectively captured using the aptamer, which increases the impedance of the electrode surfaceï¼leads to a decrease in the 2D Zn-MOF current. Bacteria can be rapidly quantified using a one-step detection method and the replacement of aptamers. The detection limits for E. coli, S. aureus, and S. typhimurium are 6, 5, and 5 CFU·mL-1, respectively. The sensor demonstrated reliable detection capabilities in real-sample testing. Therefore, the one-step sensor based on the 2D Zn-MOF and 2D C-Ti3C2Tx has significant application value in the detection of foodborne pathogens.
Assuntos
Técnicas Eletroquímicas , Escherichia coli , Salmonella typhimurium , Staphylococcus aureus , Zinco , Staphylococcus aureus/isolamento & purificação , Salmonella typhimurium/isolamento & purificação , Zinco/análise , Escherichia coli/isolamento & purificação , Técnicas Eletroquímicas/instrumentação , Técnicas Biossensoriais/instrumentação , Estruturas Metalorgânicas/química , Microbiologia de Alimentos , Titânio/química , Limite de Detecção , Eletrodos , Contaminação de Alimentos/análiseRESUMO
Foodborne pathogens remain a serious health issue in developed and developing countries. Safeness of food products has been assured for years with culture-based microbiological methods; however, these present several limitations such as turnaround time and extensive hands-on work, which have been typically address taking advantage of DNA-based methods such as real-time PCR (qPCR). These, and other similar techniques, are targeted assays, meaning that they are directed for the specific detection of one specific microbe. Even though reliable, this approach suffers from an important limitation that unless specific assays are design for every single pathogen potentially present, foods may be considered erroneously safe. To address this problem, next-generation sequencing (NGS) can be used as this is a nontargeted method; thus it has the capacity to detect every potential threat present. In this chapter, a protocol for the simultaneous detection and preliminary serotyping of Salmonella enterica serovar Enteritidis, Salmonella enterica serovar Typhimurium, Listeria monocytogenes, and Escherichia coli O157:H7 is described.
Assuntos
Microbiologia de Alimentos , Doenças Transmitidas por Alimentos , Sequenciamento de Nucleotídeos em Larga Escala , Listeria monocytogenes , Microbiologia de Alimentos/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Doenças Transmitidas por Alimentos/microbiologia , Doenças Transmitidas por Alimentos/diagnóstico , Listeria monocytogenes/isolamento & purificação , Listeria monocytogenes/genética , Escherichia coli O157/isolamento & purificação , Escherichia coli O157/genética , Humanos , Sorotipagem/métodos , DNA Bacteriano/genética , DNA Bacteriano/análise , Salmonella typhimurium/isolamento & purificação , Salmonella typhimurium/genéticaRESUMO
Objective: Persister cells are a specific subset of bacteria capable of surviving exposure to lethal doses of antibiotics, leading to antibiotic therapy failures and infection relapses. This research explores the utilization of drug repositioning to target the Lon protease in Salmonella Typhimurium. Method: In this study, FDA-approved drugs sourced from the Drug Bank database were screened to identify existing pharmaceuticals with the potential to combat the Lon protease. The formation of persister cells in the presence of antibiotics, as well as the combination of antibiotics with potential Lon protease inhibitors, was examined. Furthermore, the expression of type II toxin-antitoxin system genes was analyzed to enhance our comprehension of the inhibitors' effects. Result: Molecular docking analysis revealed that Diosmin and Nafcillin exhibited strong binding affinity to the Lon protease. Molecular dynamics simulation trajectories analysis demonstrated that the interaction of these ligands with the enzyme did not induce instability; rather, the enzyme's structure remained stable. Combinations of ceftazidime and ciprofloxacin with either Nafcillin or Diosmin led to significant reductions in bacterial cell counts. Furthermore, the effectiveness of these combinations, when compared to antibiotics alone, highlighted the substantial impact of Nafcillin and Diosmin in reducing type II TA system gene expression. Conclusion: These findings suggest promising prospects for developing novel therapeutic approaches targeting persister cells to mitigate treatment failures in Salmonella infections.
Assuntos
Antibacterianos , Reposicionamento de Medicamentos , Simulação de Acoplamento Molecular , Protease La , Salmonella typhimurium , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/crescimento & desenvolvimento , Salmonella typhimurium/genética , Protease La/metabolismo , Protease La/genética , Antibacterianos/farmacologia , Simulação de Dinâmica Molecular , Testes de Sensibilidade Microbiana , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Ciprofloxacina/farmacologia , Inibidores de Proteases/farmacologiaRESUMO
An innovative method is introduced based on the combination of label-free surface-enhanced Raman scattering with advanced multivariate analysis. This technique allows both quantitative and qualitative assessment of Salmonella typhimurium and Escherichia coli on eggshells. Using silver nanocubes embedded in polydimethylsiloxane, we consistently achieved Raman spectra of bacteria. The stability of the Ag NCs@PDMS substrate is confirmed using rhodamine 6G over 30 days under standard conditions. Principal component analysis (PCA) effectively distinguishes between S. typhimurium and E. coli spectra. Partial least squares regression (PLS) models were developed for quantitative determination of bacteria on egg surfaces, yielding accurate results with minimal error. The S. typhimurium model achieves Rc2 = 0.9563 and RMSEC = 0.601 in calibration, and Rv2 = 0.9113 and RMSEV = 0.907 in validation. Similarly, the E. coli model achieves Rc2 = 0.9877 and RMSEC = 0.322 in calibration, and Rv2 = 0.9606 and RMSEV = 0.579 in validation. Recoveries validate PLS predictions by inoculating egg surfaces with varying bacterial amounts. Our study demonstrates the feasibility of SERS-PLS for quantitative determination of S. typhimurium and E. coli on eggshells, promising enhanced food safety protocols.
Assuntos
Dimetilpolisiloxanos , Ovos , Escherichia coli , Nanopartículas Metálicas , Salmonella typhimurium , Prata , Análise Espectral Raman , Análise Espectral Raman/métodos , Prata/química , Salmonella typhimurium/isolamento & purificação , Escherichia coli/isolamento & purificação , Nanopartículas Metálicas/química , Dimetilpolisiloxanos/química , Ovos/microbiologia , Animais , Microbiologia de Alimentos/métodos , Casca de Ovo/microbiologia , Casca de Ovo/química , Análise de Componente Principal , Contaminação de Alimentos/análiseRESUMO
A highly specific and sensitive rapid two-signal assay was developed for the detection of Salmonella typhimurium in foods of animal origin. The invA gene of Salmonella was used as the biorecognition element and recombinase-assisted amplification (RAA) technology for signal amplification. By utilizing the specific recognition and efficient trans-cleavage activity of CRISPR/Cas12a, point-of-care testing (POCT) for S. typhimurium was achieved via lateral flow strips (LFS) and personal glucometer (PGM) biosensors as dual signal readout systems, with sensitivities of 33 CFU/mL and 20 CFU/mL, respectively. Users can select the appropriate test system on the basis of specific application requirements: LFSs are ideal for rapid onsite screening, whereas glucometer biosensors offer precise quantitative determination. This approach simplifies the use of large instruments and overcomes site constraints, demonstrating good accuracy and applicability in animal-derived samples, with significant potential for the detection of other pathogens and for use in restricted environments.
Assuntos
Proteínas de Bactérias , Técnicas Biossensoriais , Sistemas CRISPR-Cas , Microbiologia de Alimentos , Salmonella typhimurium , Técnicas Biossensoriais/métodos , Técnicas Biossensoriais/instrumentação , Animais , Salmonella typhimurium/isolamento & purificação , Salmonella typhimurium/genética , Proteínas de Bactérias/genética , Técnicas de Amplificação de Ácido Nucleico/métodos , Proteínas Associadas a CRISPR/genética , Limite de Detecção , Contaminação de Alimentos/análise , Endodesoxirribonucleases , Recombinases/metabolismo , Testes ImediatosRESUMO
Layered transition metal dichalcogenides (TMDs), with an extensive surface area, intriguing tunable electrical and optical features, and a distinctive Van der Waals layered structure, yield outstanding sensing properties. Essentially, most TMDs originally existed in the crystallographic phase of a 2H trigonal prismatic structure, which is semiconducting in nature with poor electrocatalytic activity. In contrast, vanadium diselenide (VSe2) with its metastable metallic 1 T octahedral crystal structure has been proven to be an outstanding electrode material, embracing exceptional electrocatalytic behavior for various electrochemical (EC) applications. However, practically, VSe2 has hardly ever been explored in the field of biosensing technology. This study presents a novel EC biosensor based on the antibody of Salmonella Typhimurium (Anti-ST) immobilized on VSe2-supported Indium tin oxide (Anti-ST/VSe2/ITO) for quantitative and efficient Salmonella Typhimurium (ST) detection. The Anti-ST/VSe2/ITO bioelectrode displayed a linear relationship with ST concentration (1.3 × 10-107 CFU/ml) with a limit of detection (LOD) (0.096 CFU/ml) that is lower than previously reported ST biosensors and impressively high sensitivity (0.001996 µA.mL/CFU). Furthermore, the proposed electrode's electroanalytical activity was evaluated in spiked sugarcane juice, demonstrating distinguished applicability for specific ST detection in real samples.
Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Salmonella typhimurium , Salmonella typhimurium/isolamento & purificação , Salmonella typhimurium/imunologia , Compostos de Selênio/química , Eletrodos , Limite de Detecção , Imunoensaio/métodosRESUMO
Itaconate serves as an immune-specific metabolite that regulates gene transcription and metabolism in both host and pathogens. S-itaconation is a post-translational modification that regulates immune response; however, its antimicrobial mechanism under the physiological condition remains unclear. Here, we apply a bioorthogonal itaconate probe to perform global profiling of S-itaconation in living pathogens, including S. Typhimurium, S. aureus, and P. aeruginosa. Some functional enzymes are covalently modified by itaconate, including those involved in the de novo purine biosynthesis pathway. Further biochemical studies demonstrate that itaconate suppresses this specific pathway to limit Salmonella growth by inhibiting the initiator purF to lower de novo purine biosynthesis and simultaneously targeting the guaABC cluster to block the salvage route. Our chemoproteomic study provides a global portrait of S-itaconation in multiple pathogens and offers a valuable resource for finding susceptible targets to combat drug-resistant pathogens in the future.
Assuntos
Proteômica , Purinas , Succinatos , Succinatos/farmacologia , Succinatos/metabolismo , Purinas/biossíntese , Purinas/farmacologia , Proteômica/métodos , Staphylococcus aureus/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/metabolismo , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/metabolismo , Proteínas de Bactérias/metabolismoRESUMO
Introduction. Disruptions in gut microbiota, known as dysbiosis, have been increasingly linked to pathogenic infections, with Salmonella Typhimurium being a notable contributor to these disturbances.Hypothesis. We hypothesize that the S. Typhimurium 14028 WT strain induces significant dysbiosis in the rat gut microbiota and that the dam and seqA genes play crucial roles in this process.Aim. In this study, it was aimed at investigating the dysbiotic activity of the S. Typhimurium 14028 WT strain on the rat gut microbiota and the roles of dam and seqA genes on this activity.Method. Changes in the rat gut microbiota were determined by examining the anal swap samples taken from the experimental groups of these animals using 16S rRNA high-throughput sequencing technology.Results. In the experimental groups, the dominant phyla were determined to be Firmicutes and Bacteroidetes (P<0.05). However, while the rate of Bacteroidetes was significantly reduced in those treated with the WT and seqA mutants, no significant difference was observed in the dam mutant compared to the control group (P<0.05). In all experimental animals, the dominant species was determined to be Prevotella copri, regardless of the experiment time and application. The analysis results of the samples taken on the third day from the rat groups infected with the S. Typhimurium 14028 WT strain (W2) presented the most striking data of this study.Conclusion. Through distance analysis, we demonstrated that a successful Salmonella infection completely changes the composition of the microbiota, dramatically reduces species diversity and richness in the microbiota and encourages the growth of opportunistic pathogens.
Assuntos
Disbiose , Microbioma Gastrointestinal , RNA Ribossômico 16S , Salmonella typhimurium , Animais , Salmonella typhimurium/genética , Salmonella typhimurium/isolamento & purificação , Microbioma Gastrointestinal/genética , Disbiose/microbiologia , Ratos , RNA Ribossômico 16S/genética , Masculino , Mutação , Salmonelose Animal/microbiologia , Proteínas de Bactérias/genética , Ratos Sprague-DawleyRESUMO
Human CD81 and CD9 are members of the tetraspanin family of proteins characterized by a canonical structure of four transmembrane domains and two extracellular loop domains. Tetraspanins are known as molecular facilitators, which assemble and organize cell surface receptors and partner molecules forming clusters known as tetraspanin-enriched microdomains. They have been implicated to play various biological roles including an involvement in infections with microbial pathogens. Here, we demonstrate an important role of CD81 for the invasion of epithelial cells by Salmonella enterica. We show that the overexpression of CD81 in HepG2 cells enhances invasion of various typhoidal and non-typhoidal Salmonella serovars. Deletion of CD81 by CRISPR/Cas9 in intestinal epithelial cells (C2BBe1 and HT29-MTX-E12) reduces S. Typhimurium invasion. In addition, the effect of human CD81 is species-specific as only human but not rat CD81 facilitates Salmonella invasion. Finally, immunofluorescence microscopy and proximity ligation assay revealed that both human tetraspanins CD81 and CD9 are recruited to the entry site of S. Typhimurium during invasion but not during adhesion to the host cell surface. Overall, we demonstrate that the human tetraspanin CD81 facilitates Salmonella invasion into epithelial host cells.
Assuntos
Células Epiteliais , Salmonella enterica , Tetraspanina 28 , Tetraspanina 29 , Humanos , Tetraspanina 28/metabolismo , Tetraspanina 28/genética , Células Epiteliais/microbiologia , Tetraspanina 29/metabolismo , Tetraspanina 29/genética , Animais , Salmonella enterica/genética , Salmonella enterica/fisiologia , Salmonella typhimurium/genética , Salmonella typhimurium/patogenicidade , Salmonella typhimurium/metabolismo , Salmonella typhimurium/fisiologia , Células Hep G2 , Ratos , Infecções por Salmonella/microbiologia , Células HT29RESUMO
Salmonella is a globally prevalent foodborne pathogen, and adverse events caused by S. Enteritidis and S. Typhimurium are extremely common. With the emergence of drug resistance, there is an urgent need for efficient and specific lytic bacteriophages as alternative to antibiotics in clinical practice. In this study, phage P6 was isolated and screened from effluent and fecal samples from duck farm environments to specifically lyse the duck sources S. Typhimurium and S. Enteritidis. Phage P6 belongs to the genus Lederbergvirus, unclassified Lederbergvirus species. The phage P6 genome did not contained non-coding RNA, virulence genes and drug resistance genes, indicating that phage P6 was biologically safe for clinical applications. Phage P6 lysed 77.78% (28/36) of multidrug-resistant Salmonella and reduced biofilms formed by S. Enteritidis CVCC 3377, 4, and 24, and S. Typhimurium 44 by 44% to 75% within 3 h, and decreased Salmonella in duckling feces by up to 1.64 orders of magnitude. Prokaryotic expression of endolysin LysP6 lysed the chloroform-treated bacterial outer membrane from different serotypes of duck-derived Salmonella and E. coli standard strain ATCC 25922. The host range was expanded compared to phage P6, and the growth of Salmonella was effectively inhibited by LysP6 in conjunction with the membrane permeabilizer EDTA within 24 h. Therefore, phage P6 and phage-derived endolysins LysP6 are suitable for application as potent biocontrol agents to improve poultry health and food safety.
Assuntos
Patos , Endopeptidases , Fagos de Salmonella , Salmonella typhimurium , Esgotos , Animais , Fagos de Salmonella/fisiologia , Esgotos/virologia , Esgotos/microbiologia , Endopeptidases/farmacologia , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/virologia , Salmonella enteritidis/efeitos dos fármacos , Salmonella enteritidis/virologia , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/virologia , Doenças das Aves Domésticas/prevenção & controle , Salmonelose Animal/microbiologia , Salmonelose Animal/prevenção & controle , Fezes/microbiologia , Fezes/virologiaRESUMO
The Ames test is used worldwide to initially screen the mutagenic potential of new chemicals. In the standard Ames test, S. typhimurium strains (TA100, TA98, TA1535, and TA1537) and Escherichia coli (WP2uvrA) are treated with substances with/without cytochrome P450s (CYPs)-induced rat S9 fractions for identifying mutagens and pro-mutagens. However, many substances show completely different toxicity patterns depending on whether the liver S9 fraction belongs to rats or humans. The natural product Polygoni Multiflori Radix (PMR) can also show bacterial reverse mutation, followed by the rat or human liver S9 fraction. While PMR elicits reverse mutations in the TA1537 strain in rat liver S9 but not in human liver S9, this mechanism has not been verified yet. To explain this, the differences in metabolic enzymes compositions commonly observed between rats and humans have been implicated. This study aimed to explore the key factors that cause differences in the genotoxicity of PMR between rat and human liver S9 metabolic enzymes. The results of next-generation sequencing (NGS) analysis showed that both rat and human metabolic enzymes caused similar mutations in TA1537. However, when the metabolic enzymes in each S9 fraction were analyzed using ion mobility tandem mass spectrometry (IM-MS), rat- and human-specific enzymes were identified among the cytochrome (CYP) family, especially aryl hydrocarbon receptor (AHR)-related CYPs. These findings suggest that CYP1A1 isoforms contribute to the mechanism of PMR in the Ames test. Therefore, an in vitro Ames test might be more reliable in predicting genotoxicity for both rodents and humans. This will also help overcome the limitations of laboratory animal-based toxicity evaluations, which provide unreliable results due to interspecies differences between humans and rodents.
Assuntos
Testes de Mutagenicidade , Mutagênicos , Salmonella typhimurium , Animais , Humanos , Testes de Mutagenicidade/métodos , Ratos , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Mutagênicos/toxicidade , Fígado/efeitos dos fármacos , Fígado/metabolismo , Ativação Metabólica , Escherichia coli/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Sistema Enzimático do Citocromo P-450/genética , Mutação , Dano ao DNA/efeitos dos fármacos , Fallopia multiflora/química , MasculinoRESUMO
Salmonella Typhimurium (S. Typhimurium) infections can lead to severe intestinal damage and reduce growth performance in broilers. Thus, this study examined the potential mitigating impact of sodium humate (HNa) on intestinal barrier damage resulting from S. Typhimurium infection in broilers. A total of 320 1-day-old Arbor Acres broilers were randomly assigned into 5 treatments with 8 replicates. On d 22-24, broilers in the CON group were challenged with 1 ml of PBS, while broilers in the other groups were challenged with 1 ml of 3 × 109 CFU/ml S. Typhimurium, daily. Dietary administration with 4 g/kg of HNa increased (P < 0.05) the final body weight, jejunal secretory immunoglobulin A (sIgA), total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), and catalase (CAT) levels as compared with the MOD group broilers. Furthermore, HNa alleviated intestinal barrier damage by increasing villus height (VH), upregulating protein expression of Occludin, Claudin-1, and zonula occludens-1 (ZO-1), inhibiting toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) signaling pathway activation, and decreasing the secretion of inflammatory cytokines (P < 0.05). Collectively, the present study showed that HNa mitigated intestinal barrier damage induced by S. Typhimurium infection in broilers.
Assuntos
Antioxidantes , Galinhas , Mucosa Intestinal , NF-kappa B , Doenças das Aves Domésticas , Salmonelose Animal , Salmonella typhimurium , Receptor 4 Toll-Like , Animais , Galinhas/microbiologia , Doenças das Aves Domésticas/microbiologia , Doenças das Aves Domésticas/prevenção & controle , NF-kappa B/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiologia , Antioxidantes/metabolismo , Salmonelose Animal/prevenção & controle , Salmonelose Animal/microbiologia , Receptor 4 Toll-Like/metabolismo , Superóxido Dismutase/metabolismo , Transdução de Sinais , Citocinas/metabolismo , Imunoglobulina A Secretora/metabolismo , Catalase/metabolismo , Intestinos/microbiologia , Claudina-1/metabolismo , Ocludina/metabolismo , Proteína da Zônula de Oclusão-1/metabolismo , Mediadores da Inflamação/metabolismo , Regulação para CimaRESUMO
In this study, hazardous wastes including fluff, dust, and scrubbing sludge were sampled in 2019 from two metal shredding facilities located in Wallonia, Belgium. To assess the extent of the contamination, a global approach combining chemical and biological techniques was used, to better reflect the risks to health and the environment. The samples investigated induced significant in vitro aryl hydrocarbon receptor (AhR) agonistic bioactivities and estrogenic receptor (ERα) (ant)agonistic bioactivities in the respective CALUX (chemical activated luciferase gene expression) bioassays. The mutagenicity of the samples was investigated with the bacterial reverse gene mutation test using the Salmonella typhimurium TA98 and TA100 strains. Except for the sludge sample (site 3), all samples induced a mutagenic response in the TA98 strain (± S9 metabolic fraction) whereas in the TA100 strain (+ S9 metabolic fraction), only the sludge sample (site 2) showed a clear mutagenic effect. The in vivo toxicity/teratogenicity of the shredder wastes was further evaluated with zebrafish embryos. Except for the dust sample (site 2), all samples were found to be teratogenic as they returned teratogenic indexes (TIs) > 1. The high levels of contamination, the mutagenicity, and the teratogenicity of these shredder wastes raise significant concerns about their potential negative impacts on both human health and environment.
Assuntos
Testes de Mutagenicidade , Receptores de Hidrocarboneto Arílico , Bélgica , Animais , Peixe-Zebra , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Receptor alfa de Estrogênio , Metais/toxicidade , Mutagênicos/toxicidadeRESUMO
BACKGROUND: Salmonella Typhimurium poses a serious threat to human health worldwide, necessitating the development of a rapid, sensitive, and convenient method for S. Typhimurium detection. Nanozymes are considered ideal signal report elements, which are extensively used for developing colorimetric methods. However, single-component nanozymes display low catalytic activity, and colorimetric methods are susceptible to environmental interference, reducing the sensitivity and accuracy of detection results. To address these drawbacks, this study constructed a dual-mode composite nanozyme-based cascade colorimetric-fluorescence aptasensor for S. Typhimurium detection in food. RESULTS: In this study, the composite Fe3O4@MIL-100(Fe) nanozymes were successful synthesized and demonstrated substantial peroxide-like activity, with 4.76-fold higher specificity activity (SA) than that of Fe3O4 nanozymes. Then, a glucose oxidase (GOx)-Fe3O4@MIL-100(Fe) cascade reaction was developed for colorimetric detection via an aptamer to facilitate the formation of Fe3O4@MIL-100(Fe)/S. Typhimurium/carboxylated g-C3N4 (CCN)-GOx sandwich complexes. Meanwhile, the fluorescence mode was achieved by measuring the fluorescence intensity of the sandwich complexes. In optimum conditions, the dual-mode detection limits (LOD) were 1.8 CFU/mL (colorimetric mode) and 1.2 CFU/mL (fluorescence mode), respectively, with the S. Typhimurium concentration ranging from 10 CFU/mL to 107 CFU/mL. Finally, the feasibility of the dual-mode colorimetric-fluorescence method was validated via three actual samples, yielding recovery rates of 77.32 % to91.17 % and 82.17 % to 103.7 %, respectively. SIGNIFICANCE AND NOVELTY: This study successfully develops a composite nanozyme-based cascade colorimetric and fluorescence dual-mode aptasensor for S. Typhimurium detection. It presents several distinct benefits, such as a broader linear range (10-107 CFU/mL), a lower LOD value (1.2 CFU/mL), and more accurate results. More importantly, the proposed dual-mode method displays a low LOD in colorimetric mode, demonstrating considerable potential for S. Typhimurium on-site detection in food.
Assuntos
Aptâmeros de Nucleotídeos , Colorimetria , Salmonella typhimurium , Salmonella typhimurium/isolamento & purificação , Colorimetria/métodos , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Limite de Detecção , Fluorescência , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Estruturas Metalorgânicas/química , Espectrometria de FluorescênciaRESUMO
Western diets are the underlying cause of metabolic and liver diseases. Recent trend to limit the consumption of protein-rich animal products has become more prominent. This dietary change entails decreased protein consumption; however, it is still unknown how this affects innate immunity. Here, we studied the influence of a low protein diet (LPD) on the liver response to bacterial infection in mice. We found that LPD protects from Salmonella enterica serovar Typhimurium (S. Typhimurium)-induced liver damage. Bulk and single-cell RNA sequencing of murine liver cells showed reduced inflammation and upregulation of autophagy-related genes in myeloid cells in mice fed with LPD after S. Typhimurium infection. Mechanistically, we found reduced activation of the mammalian target of rapamycin (mTOR) pathway, whilst increased phagocytosis and activation of autophagy in LPD-programmed macrophages. We confirmed these observations in phagocytosis and mTOR activation in metabolically programmed human peripheral blood monocyte-derived macrophages. Together, our results support the causal role of dietary components on the fitness of the immune system.
Assuntos
Autofagia , Dieta com Restrição de Proteínas , Fígado , Macrófagos , Camundongos Endogâmicos C57BL , Salmonella typhimurium , Serina-Treonina Quinases TOR , Animais , Serina-Treonina Quinases TOR/metabolismo , Macrófagos/metabolismo , Macrófagos/imunologia , Camundongos , Fígado/metabolismo , Humanos , Infecções por Salmonella/microbiologia , Infecções por Salmonella/imunologia , Infecções por Salmonella/prevenção & controle , Masculino , Fagocitose , Transdução de SinaisRESUMO
Salmonella translocate to the gut epithelium via microfold cells lining the follicle-associated epithelium (FAE). How Salmonella localize to the FAE is not well characterized. Here we use live imaging and competitive assays between wild-type and chemotaxis-deficient mutants to show that Salmonella enterica serotype Typhimurium (S. Typhimurium) localize to the FAE independently of chemotaxis in an ex vivo mouse caecum infection model. Electrical recordings revealed polarized FAE with sustained outward current and small transepithelial potential, while the surrounding villus is depolarized with inward current and large transepithelial potential. The distinct electrical potentials attracted S. Typhimurium to the FAE while Escherichia coli (E. coli) localized to the villi, through a process called galvanotaxis. Chloride flux involving the cystic fibrosis transmembrane conductance regulator (CFTR) generated the ionic currents around the FAE. Pharmacological inhibition of CFTR decreased S. Typhimurium FAE localization but increased E. coli recruitment. Altogether, our findings demonstrate that bioelectric cues contribute to S. Typhimurium targeting of specific gut epithelial locations, with potential implications for other enteric bacterial infections.
Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística , Escherichia coli , Mucosa Intestinal , Salmonella typhimurium , Animais , Camundongos , Salmonella typhimurium/fisiologia , Salmonella typhimurium/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/metabolismo , Regulador de Condutância Transmembrana em Fibrose Cística/genética , Escherichia coli/metabolismo , Escherichia coli/fisiologia , Escherichia coli/genética , Mucosa Intestinal/microbiologia , Mucosa Intestinal/metabolismo , Quimiotaxia , Ceco/microbiologia , Camundongos Endogâmicos C57BL , Feminino , Modelos Animais de Doenças , HumanosRESUMO
Phillyrin is extracted from Forsythia suspensa (Thunb.) Vahl, is significantly higher in (unripe Forsythiae Fructus) Qing qiao than in (ripe Forsythiae Fructus) Lao qiao fruits of the plant. However, the toxicity of phillyrin has not been adequately investigated. The study investigates the genetic and teratogenic effects of phillyrin to determine its safety profile. Assessing the genotoxicity and teratogenicity of phillyrin involved various tests, such as the bacterial reverse mutation assay, mammalian erythrocyte micronucleus assay, spermatocyte chromosome aberration assay, and teratogenicity assay. The results demonstrated that phillyrin exhibited no discernible impact on the following: number of colonies that spontaneously revert for Salmonella typhimurium TA 97, TA98, TA100, TA102, and TA1535, frequency of bone marrow polychromatic erythrocytes, and the rate of chromosomal aberrations. In the teratogenicity test, the pregnant rats exhibited no signs of toxicity or abnormal changes, and the growth, embryonic development, and visual anatomy of each pup were normal. In comparison with the negative control group, there were no significant differences in fetal body weight, mortality, deformity rate, malformed nest rate, gravid uterus weight, average number of fetuses per litter, fetal body length, or visceral and skeletal development in each dose group. In conclusion, these findings provide evidence that phillyrin does not exhibit genotoxic or teratogenic effects, supporting its potential safety for pharmacological applications.
Assuntos
Aberrações Cromossômicas , Testes de Mutagenicidade , Teratogênicos , Animais , Feminino , Masculino , Teratogênicos/toxicidade , Ratos , Aberrações Cromossômicas/induzido quimicamente , Camundongos , Testes para Micronúcleos , Gravidez , Ratos Sprague-Dawley , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , GlucosídeosRESUMO
Agricultural environments are becoming increasingly contaminated with plastic pollution. Plastics in the environment can also provide a unique habitat for microbial biofilm, termed the 'plastisphere', which can also support the persistence of human pathogens such as Salmonella. Human enteric Salmonella enterica serovar Typhimurium can enter agricultural environments via flooding or from irrigation with contaminated water. Using soil mesocosms we quantified the ability of S. Typhimurium to persist on microplastic beads in two agriculturally relevant soils, under ambient and repeat flood scenarios. S. Typhimurium persisted in the plastisphere for 35 days in both podzol and loamy soils; while during multiple flood events was able to survive in the plastisphere for up to 21 days. S. Typhimurium could dissociate from the plastisphere during flooding events and migrate through soil in leachate, and importantly could colonise new plastic particles in the soil, suggesting that plastic pollution in agricultural soils can aid S. Typhimurium persistence and facilitate further dissemination within the environment. The potential for increased survival of enteric human pathogens in agricultural and food production environments due to plastic contamination poses a significant public health risk, particularly in potato or root vegetable systems where there is the potential for direct contact with crops.
Assuntos
Agricultura , Microplásticos , Salmonella typhimurium , Microbiologia do Solo , Poluentes do Solo , Solo , Solo/química , Polietileno , PlásticosRESUMO
Leuconostoc lactis DMLL10 is a microorganism specific to kimchi fermentation. In this study, we sought to evaluate the toxicity of this strain, which was newly isolated from kimchi, to determine its safety as a food ingredient. Bacterial reverse mutation assay, chromosomal aberration assay, and mammalian cell in vitro micronucleus assay were performed to assess the genetic toxicity of Leu. lactis DMLL10. The strain did not induce mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA1537, or Escherichia coli WP2uvrA, with or without metabolic activation of S9 mixture. The oral administration of Leu. lactis DMLL10 also did not significantly increase the number of micronucleated polychromatic erythrocytes, or the mean ratio of polychromatic to total erythrocytes. Additionally, Leu. lactis DMLL10 did not cause a significant chromosomal aberration in CHU/IL cells in the presence or absence of S9 activation. Therefore, Leu. lactis DMLL10 can be suggested as a functional food ingredient with reliability and safety.
Assuntos
Aberrações Cromossômicas , Alimentos Fermentados , Leuconostoc , Testes de Mutagenicidade , Salmonella typhimurium , Alimentos Fermentados/microbiologia , Animais , Salmonella typhimurium/genética , Salmonella typhimurium/efeitos dos fármacos , Leuconostoc/genética , Leuconostoc/isolamento & purificação , Leuconostoc/metabolismo , Escherichia coli/genética , Camundongos , Mutagênicos/toxicidade , Mutagênicos/metabolismo , Fermentação , Testes para Micronúcleos , Microbiologia de AlimentosRESUMO
Brown adipose tissue (BAT) combusts lipids and glucose to generate heat. Via this process of nonshivering thermogenesis, BAT plays a pivotal role in thermoregulation in cold environments, but its contribution to immune-induced fever is less clear. Male APOE∗3-Leiden.CETP mice, a well-established model for human-like lipoprotein metabolism, and wild-type mice were given an intraperitoneal injection of Salmonella enterica serovar Typhimurium (S.tm). Energy expenditure and substrate utilization, plasma lipid levels, fatty acid (FA) uptake by adipose tissues, and lipid content and thermogenic markers in adipose tissues were examined. S.tm infection led to a set of characteristic symptoms, including elevated body temperature and decreased body weight. Whole-body energy expenditure was significantly decreased 72 h postinfection, but fat oxidation was increased and accompanied by a substantial reduction in plasma triglyceride (TG) levels as demonstrated in APOE∗3-Leiden.CETP mice. S.tm infection strongly increased uptake of FAs from TG-rich lipoproteins by BAT, which showed a positive correlation with body temperature in infected mice. Upon histological examination of BAT from wild-type or APOE∗3-Leiden.CETP mice, elevated levels of tyrosine hydroxylase were observed, indicative of stimulated sympathetic activity. In addition, the gene expression profile was consistent with more adrenergic stimulation, while lipid content was reduced. Furthermore, browning of white adipose tissue was observed, evidenced by a modest increase in TG-derived FA uptake, the presence of multilocular cells, and induction of uncoupling protein 1 expression. We proposed that BAT, or thermogenic adipose tissue in general, is involved in the maintenance of elevated body temperature upon invasive bacterial infection.