Quercetin Prevents Escherichia coli O157:H7 Adhesion to Epithelial Cells via Suppressing Focal Adhesions

The attachment of Escherichia coli O157:H7 to intestinal epithelial cells is indispensable for its pathogenesis. Besides translocated-intimin receptor (Tir), E. coli O157:H7 interacts with host cell surface receptors to promote intimate adhesion. This study showed that integrin β1 was increased in Caco-2 cells upon E. coli O157:H7 infection, while Caco-2 cells subjected to integrin β1 antibody blocking or CRISPR/Cas9 knockout had reduced bacterial attachment. Infection of E. coli O157:H7 inactivated focal adhesion kinase (FAK) and paxillin, increased focal adhesion (FA) and actin polymerization, and decreased cell migration in Caco-2 cells, which were rescued by integrin β1 antibody blocking or knockout. Pre-treatment with quercetin, known for its anti-oxidant and anti-inflammatory activity, reduced bacterial infection to Caco-2 cells, which might be partially via interfering integrin β1 and FAK association augmented by E. coli O157:H7. In addition, quercetin decreased FA formation induced by bacterial infection and recovered host cell motility. Taken together, data showed that E. coli O157:H7 interacts with integrin β1 to facilitate its adhesion to host cells. Quercetin inhibits bacterial infection possibly by blocking the interaction between E. coli O157:H7 and integrin β1. Collectively, these data indicate that quercetin provides an alternative antimicrobial to mitigate and control E. coli O157:H7 intestinal infection, and suggest potential broad benefits of quercetin and related polyphenols in fighting other enteric pathogen infections

Exercise intervention to reduce mobile phone addiction in adolescents: a systematic review and meta-analysis of randomized controlled trials

BackgroundThe growing problem of adolescent mobile phone addiction has attracted significant attention, underscoring the importance of identifying approaches to address it. Exercise has been found to reduce adolescent mobile phone addiction; however, its mechanism remains unclear. This review aims to elucidate the potential moderating factors between exercise and mobile phone addiction based on previous studies to provide a reference for adolescents to effectively participate in exercise to reduce mobile phone addiction.MethodsArticles were searched in the CNKI, Web of Science, Scopus, Cochrane, PsycINFO, and PubMed databases according to the inclusion criteria and followed the Preferred Reporting Items for Systematic Assessment and Meta-analysis (PRISMA). The quality of the literature was assessed by two independent reviewers using the Cochrane Collaboration Risk of Bias tool for methodological quality assessment. Meta-analysis was performed using Stata 15.1 software for Meta-analysis, standardized mean difference (SMD) was combined using a random effects model, and subgroup analysis was used to explore heterogeneity.ResultsA total of 12 studies, 17 samples, and 861 subjects were included in the meta-analysis, and all studies were randomized controlled trials. The findings revealed that the exercise intervention significantly reduced mobile phone addiction in adolescents (SMD = −3.11; 95% CI: −3.91, −2.30; p < 0.001). The intervention effect was moderated by multiple variables, such as the measurement tools, exercise intervention types, cycles, frequency, and duration of a single exercise intervention.ConclusionOur findings suggest that exercise could serve as an effective strategy for preventing or ameliorating mobile phone addiction in adolescents. Based on the results of this study, we encourage mobile phone-addicted adolescents to engage in a single exercise using a mix of skills for 30–60 min three or more times weekly for more than eight consecutive weeks

Bacillus cereus non-haemolytic enterotoxin activates the NLRP3 inflammasome

Inflammasomes are important for host defence against pathogens and homeostasis with commensal microbes. Here, we show non-haemolytic enterotoxin (NHE) from the neglected human foodborne pathogen Bacillus cereus is an activator of the NLRP3 inflammasome and pyroptosis. NHE is a non-redundant toxin to haemolysin BL (HBL) despite having a similar mechanism of action. Via a putative transmembrane region, subunit C of NHE initiates binding to the plasma membrane, leading to the recruitment of subunit B and subunit A, thus forming a tripartite lytic pore that is permissive to efflux of potassium. NHE mediates killing of cells from multiple lineages and hosts, highlighting a versatile functional repertoire in different host species. These data indicate that NHE and HBL operate synergistically to induce inflammation and show that multiple virulence factors from the same pathogen with conserved function and mechanism of action can be exploited for sensing by a single inflammasome

Detection of Staphylococcus aureus virulence gene pvl based on CRISPR strip

IntroductionStaphylococcus aureus (S. aureus) is a prominent pathogen responsible for both hospital-acquired and community-acquired infections. Among its arsenal of virulence factors, Panton-Valentine Leucocidin (PVL) is closely associated with severe diseases such as profound skin infections and necrotizing pneumonia. Patients infected with pvl-positive S. aureus often exhibit more severe symptoms and carry a substantially higher mortality risk. Therefore, it is crucial to promptly and accurately detect pvl-positive S. aureus before initiating protective measures and providing effective antibacterial treatment.MethodsIn this study, we propose a precise identification and highly sensitive detection method for pvl-positive S. aureus based on recombinase-assisted amplification and the CRISPR-ERASE strip which we previously developed.ResultsThe results revealed that this method achieved a detection limit of 1 copy/μL for pvl-positive plasmids within 1 hour. The method successfully identified all 25 pvl-positive and 51 pvl-negative strains among the tested 76 isolated S. aureus samples, demonstrating its concordance with qPCR.DiscussionThese results show that the CRISPR-ERASE detection method for pvl-positive S. aureus has the advantages of high sensitivity and specificity, this method combines the characteristics of recombinase-assisted amplification at room temperature and the advantages of ERASE test strip visualization, which can greatly reduce the dependence on professional laboratories. It is more suitable for on-site detection than PCR and qPCR, thereby providing important value for rapid on-site detection of pvl

Disentangling land model uncertainty via Matrix-based Ensemble Model Inter-comparison Platform (MEMIP)

Background Large uncertainty in modeling land carbon (C) uptake heavily impedes the accurate prediction of the global C budget. Identifying the uncertainty sources among models is crucial for model improvement yet has been difficult due to multiple feedbacks within Earth System Models (ESMs). Here we present a Matrix-based Ensemble Model Inter-comparison Platform (MEMIP) under a unified model traceability framework to evaluate multiple soil organic carbon (SOC) models. Using the MEMIP, we analyzed how the vertically resolved soil biogeochemistry structure influences SOC prediction in two soil organic matter (SOM) models. By comparing the model outputs from the C-only and CN modes, the SOC differences contributed by individual processes and N feedback between vegetation and soil were explicitly disentangled. Results Results showed that the multi-layer models with a vertically resolved structure predicted significantly higher SOC than the single layer models over the historical simulation (1900–2000). The SOC difference between the multi-layer models was remarkably higher than between the single-layer models. Traceability analysis indicated that over 80% of the SOC increase in the multi-layer models was contributed by the incorporation of depth-related processes, while SOC differences were similarly contributed by the processes and N feedback between models with the same soil depth representation. Conclusions The output suggested that feedback is a non-negligible contributor to the inter-model difference of SOC prediction, especially between models with similar process representation. Further analysis with TRENDY v7 and more extensive MEMIP outputs illustrated the potential important role of multi-layer structure to enlarge the current ensemble spread and the necessity of more detail model decomposition to fully disentangle inter-model differences. We stressed the importance of analyzing ensemble outputs from the fundamental model structures, and holding a holistic view in understanding the ensemble uncertainty

Predicting nosocomial lower respiratory tract infections by a risk index based system

Although belonging to one of the most common type of nosocomial infection, there was currently no simple prediction model for lower respiratory tract infections (LRTIs). This study aims to develop a risk index based system for predicting nosocomial LRTIs based on data from a large point-prevalence survey. Among the 49328 patients included, the prevalence of nosocomial LRTIs was 1.70% (95% confidence interval [CI], 1.64% to 1.76%). The areas under the receiver operating characteristic (ROC) curve for logistic regression and fisher discriminant analysis were 0.907 (95% CI, 0.897 to 0.917) and 0.902 (95% CI, 0.892 to 0.912), respectively. The constructed risk index based system also displayed excellent discrimination (area under the ROC curve: 0.905 [95% CI, 0.895 to 0.915]) to identify LRTI in internal validation. Six risk levels were generated according to the risk score distribution of study population, ranging from 0 to 5, the corresponding prevalence of nosocomial LRTIs were 0.00%, 0.39%, 3.86%, 12.38%, 28.79% and 44.83%, respectively. The sensitivity and specificity of prediction were 0.87 and 0.79, respectively, when the best cut-off point of risk score was set to 14. Our study suggested that this newly constructed risk index based system might be applied to boost more rational infection control programs in clinical settings

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Tears evoke the intention to offer social support: A systematic investigation of the interpersonal effects of emotional crying across 41 countries

Tearful crying is a ubiquitous and likely uniquely human phenomenon. Scholars have argued that emotional tears serve an attachment function: Tears are thought to act as a social glue by evoking social support intentions. Initial experimental studies supported this proposition across several methodologies, but these were conducted almost exclusively on participants from North America and Europe, resulting in limited generalizability. This project examined the tears-social support intentions effect and possible mediating and moderating variables in a fully pre-registered study across 7007 participants (24,886 ratings) and 41 countries spanning all populated continents. Participants were presented with four pictures out of 100 possible targets with or without digitally-added tears. We confirmed the main prediction that seeing a tearful individual elicits the intention to support, d = 0.49 [0.43, 0.55]. Our data suggest that this effect could be mediated by perceiving the crying target as warmer and more helpless, feeling more connected, as well as feeling more empathic concern for the crier, but not by an increase in personal distress of the observer. The effect was moderated by the situational valence, identifying the target as part of one's group, and trait empathic concern. A neutral situation, high trait empathic concern, and low identification increased the effect. We observed high heterogeneity across countries that was, via split-half validation, best explained by country-level GDP per capita and subjective well-being with stronger effects for higher-scoring countries. These findings suggest that tears can function as social glue, providing one possible explanation why emotional crying persists into adulthood.</p

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world

MOLECULAR SIGNALING UNDERLYING ESCHERICHIA COLI O157:H7 INTESTINAL COLONIZATION AND THE PROTECTIVE ROLE OF QUERCETIN TO INHIBIT PATHOGEN INFECTION

Escherichia coli (E. coli) O157:H7 can cause severe human diseases when attaches to the intestinal epithelial cells. In this dissertation, the molecular signaling alteration underling E. coli O157:H7 colonization was investigated and the preventive effects of quercetin on bacterial infection were also observed. Autophagy is characterized as the formation of a double-membrane autophagosome and is considered a vital defense mechanism to bacterial infection. In our study, E. coli O157:H7 suppressed host autophagy and promoted bacterial adhesion via a Tir-mediated and protein kinase A (PKA)-dependent mechanism. PKA activation inhibited ERK signaling and endoplasmic reticulum (ER) stress, which subsequently inhibited autophagy. Notably, enhancing host cell autophagy reduced the bacterial adherence. However, impaired autophagy may cause sustained host inflammatory response such as inflammasomes. Inflammasomes are critical molecule platforms mediating host inflammation and processing inflammatory cytokines such interleukin (IL)-1β and IL-18. E. coli O157:H7 infection stimulated NOD-like receptor (NLR) superfamily, pyrin domain containing 3 (NLRP3) inflammasome activation and host production of IL-1β and IL-18 due to the impaired mitochondrial function and enhanced reactive oxidative species (ROS) release. Quercetin, a natural polyphenolic compound that has multiple beneficial health effects, abrogated NLRP3-induced inflammation in infected cells by inhibiting mitochondrial ROS release and enhancing host autophagy. Moreover, in order to have a better colonization, E. coli O157:H7 utilized cell surface proteins integrins to promote bacterial adhesion to host cells. We found that E. coli O157:H7 mediated epithelial cell adhesion by stabilizing focal adhesions via β1 integrins. Interference with β1 integrin significantly reduced bacterial adhesion. Importantly, quercetin had an inhibitory effect on E. coli O157:H7 adhesion, which we attributed to decreased β1 integrin expression and focal adhesion proteins recruitment.In summary, E. coli O157:H7 1) inhibited host autophagy via Tir-mediated PKA activation, 2) induced a host NLRP3 inflammasome and 3) utilized β1 integrin to favor bacterial persistence. Quercetin protected intestinal epithelial cells from inflammasome activation and adhesion in response to infection in part due to the prevention of ROS production and inhibition of β1 integrin expression and focal adhesion formation