Abstract Aims Bacterial infections of the cornea, also known as bacterial keratitis, are a major cause of blindness. The corneal surface is protected against infection by the flow of tear fluid, which displaces potential pathogens and debris. Whilst fluid flow is known to influence the behaviour of both bacterial and epithelial cells, most models of corneal infection use static conditions. Here, we develop a microfluidic model to directly visualise interactions between bacteria and human corneal epithelial cells (HCE2) in physiologically relevant flow conditions. Methods and Results We use high-resolution microscopy and automated image analysis to continuously quantify the rate at which Staphylococcus aureus (SH1000) and Pseudomonas aeruginosa (PAO1) adhere to HCE2 monolayers. We then use this system to investigate the effects of pre-treatment with unfractionated heparin (UFH), a putative therapeutic compound thought to inhibit bacterial adhesion. Using a traditional, well plate-based assay that lacks fluid flow, prior treatment of HCE2 monolayers with UFH significantly reduced adhesion of both species. In our microfluidic model we found that pre-treating HCE2 monolayers with UFH again sharply reduced S. aureus adhesion, but surprisingly, UFH pre-treatment had no effect on P. aeruginosa adhesion to corneal cells in the presence of fluid flow. Conclusions Our findings demonstrate that incorporating fluid flow into in vitro infection models can lead to qualitatively different outcomes when screening putative anti-adhesion therapies. These findings, obtained using two widely studied model strains, illustrate how microfluidic models of infection can offer valuable insights into how flow influences bacterial keratitis and guide the development of new treatments.
AIMS Armillaria gallica is a medicinal fungus and key symbiont for Gastrodia elata cultivation. This study aimed to investigate the dose-dependent effects of exogenous selenium (Se) on mycelial growth, Se accumulation and biotransformation, antioxidant regulation, and transcriptional responses in A. gallica. METHODS AND RESULTS Dose-response experiments showed that 20 mg L-1 Na2SeO3 optimally promoted mycelial biomass (47% increase) and Se accumulation (837.53 mg kg-1), with 99.71% of Se in organic forms, predominantly associated with polysaccharides and proteins. Physiological assays revealed enhanced SOD, POD, CAT, and GPx activities and reduced MDA content under Se treatment. Transcriptomic profiling identified extensive gene remodeling in ion transport, redox metabolism, carbohydrate metabolism, glutathione metabolism, and MAPK signaling pathways, with qRT-PCR validating key DEG expression patterns. CONCLUSIONS Appropriate Se concentration promotes A. gallica growth and enhances antioxidant capacity through coordinated transcriptional and metabolic regulation. The strong Se accumulation and biotransformation capacity position A. gallica as a promising candidate for Se biofortification and for developing Se-enriched Gastrodia elata via the Armillaria-Gastrodia symbiotic system.
Abstract Aims This study takes rice as the model system, aiming to dissect the cross-kingdom interaction and synergistic growth-promoting mechanisms between the entomopathogenic fungus Metarhizium robertsii and six Streptomyces strains, and to systematically screen for the optimal synergistic combination. Furthermore, this study seeks to situate the above interaction analysis within the framework of rational design of synthetic microbial communities, thereby providing a transferable mechanistic basis and candidate strain resources for constructing functional SynComs based on fungal–bacterial cross-kingdom synergy. Methods and Results A systematic screening pipeline was established, integrating plate confrontation assays, hydroponic bioassays, and highperformance liquid chromatography (HPLC)based metabolic profiling. Among the tested combinations, Streptomyces pactum L6 exhibited no detectable antagonism toward MAA in vitro. In hydroponic culture, the MAA–L6 consortium significantly and consistently increased rice plant height, root length, root activity, and endogenous indole3acetic acid (IAA) content, and its growth-promoting effect was significantly superior to that of either strain applied alone, demonstrating the strongest synergistic effect among all tested combinations. HPLC analysis revealed novel metabolite peaks in the L6–MAA coculture that were absent in either monoculture, indicating that interspecific interactions induced de novo metabolite synthesis and unique metabolic reprogramming. Conclusions Crosskingdom synergy between M. robertsii and Streptomyces can promote rice growth by modulating root physiological activities and metabolic profiles. These findings provide both a theoretical foundation and practical microbial resources for developing fertilizer-reducing synthetic microbial SynComs suited to rice cultivation.
Abstract Aims Salmonella enterica, a major cause of foodborne outbreaks associated with ready-to-eat leafy greens, like lettuce, poses urgent challenges to food safety. In this study, a lytic phage, SWJM-03, was isolated and evaluated for its potential as a biocontrol agent against Salmonella contamination in lettuce. Methods and Results Phage SWJM-03 was isolated from sewage using multidrug-resistant Salmonella Typhimurium 2112 as the host, and its biological characteristics, genomic features, antibiofilm activity, and biocontrol efficacy on lettuce were evaluated. Phage SWJM-03 is classified within the genus Berlinvirus, class Caudoviricetes. The phage exhibited a short-tailed morphology and demonstrated rapid adsorption (92.7% within 20 min), a short latent period of 5 min, and a burst size of 97 PFU/cell. SWJM-03 showed high stability across a wide pH range (3–12) and retained high activity within a temperature range of 30–60°C relevant to food processing conditions. Notably, SWJM-03 also exhibited great storage stability, with minimal titer reduction after 4 weeks at 4°C, supporting its practical applicability. Genomic analysis (39 474 bp dsDNA, 48.97% G + C, GenBank Accession no.: OQ818670) confirmed the absence of virulence-associated genes. SWJM-03 significantly reduced biofilm biomass of S. Typhimurium by 56.8%, and demonstrated promising biocontrol potential. Importantly, in a simulated lettuce contamination system under refrigeration (4°C), SWJM-03 achieved up to 4.00 log₁₀ CFU/cm² reduction within 3 days, reducing bacterial counts below detectable levels (<10 CFU/cm²). Conclusions Phage SWJM-03 is a rapid-acting and environmentally stable lytic bacteriophage with strong antibacterial activity under refrigeration conditions, highlighting its potential as a promising biocontrol agent for controlling Salmonella contamination in fresh produce.
Abstract Wastewater-Based Epidemiology (WBE) is an approach that is widely used to monitor the occurrence and distribution of pathogens shed by human populations through wastewater. This review critically evaluates the application of WBE of enteric viruses within a One Health paradigm. It highlights how enteric viruses from human and animal sources end up in wastewater and aquatic environments, and how their presence can be used to predict the occurrence of diseases in human and animal populations. The review highlights the untapped potential for the application of WBE beyond human populations to a more holistic One Health approach. This study further highlights the challenges in implementation of WBE and proposes the integration of anthropogenic and socioeconomic determinants in contextualising WBE. Overall, this study proposes a holistic framework for improving the understanding of enteric viral epidemiology in wastewater environments and advancing predictive, evidence-driven public health interventions.
