World journal of microbiology & biotechnology最新文献

Vibriosis, caused by Vibrio species, threatens marine aquaculture worldwide. Traditional vaccination methods are labor-intensive, expensive, and stressful for fish. This study investigates genetically modified Nannochloropsis sp. as a novel oral vaccine carrier against vibriosis. Using homologous recombination, nitrate reductase gene was targeted to integrate an expression cassette containing the outer membrane protein kinase (OmpK) gene from V. harveyi. Transformed microalgae were generated through electroporation and screened with bleomycin. Transgenic lines were validated at genomic, transcriptional, and translational levels. The transgenic microalgae were incorporated into fish feed to assess vaccine efficacy in fish model for infectious disease, zebrafish (Danio rerio). Immune responses were analyzed by examining IgZ, TNF-α, and IL-1β gene expression. Efficacy was evaluated through histopathology and relative percentage of survival (RPS) following bacterial challenge. Results confirmed successful transformation, with microalgae surviving bleomycin screening at 30 µgml^- 1 and exhibiting expression cassette integration via PCR and RT-PCR. Western and dot blot analyses confirmed OmpK protein expression. Vaccinated fish showed increased IgZ expression, indicating robust immune response. Fish receiving the oral vaccine achieved 90 ± 3% RPS compared to 36 ± 4.36% in controls. This approach promises to revolutionize fish vaccination, enhance aquaculture productivity, and reduce antibiotic dependence.

Preservatives, including antimicrobial compounds, are routinely added to home and personal care products such as dishwashing detergents to prevent microbial contamination during repeated consumer use. Traditional antimicrobial efficacy testing (T-AET) relies on colony counting methods, where microbial cocktails are inoculated into preservative-containing products and plated on agar to measure microbial survival. While considered a gold standard, T-AET is time-consuming, labor-intensive, costly, and prone to variability and error due to manual handling. To address these limitations, we developed a high-throughput, miniature, ATP-based, on-chip AET (O-AET) using a 384PillarPlate platform. Pseudomonas aeruginosa, Enterobacter cloacae, and Staphylococcus aureus were encapsulated in 3% agarose and exposed to test compounds and detergent formulations. ATP levels in viable microbes were quantified using the BacTiter-Glo™ luminescence assay to generate dose-response curves, IC₅₀ values, and log reduction measurements. Two industrial antimicrobials, Acticide LG and Acticide MBR2, were evaluated, showing CV values below 8%. Nine detergent formulations from Colgate-Palmolive, including both fresh and aged samples (stored for 8 weeks at 40 °C), were tested. Log reduction data from O-AET showed strong correlation with T-AET. Using a 3-log reduction cutoff, O-AET achieved 98% sensitivity, 44% specificity, and 71% overall predictivity. The lower specificity was partly attributed to limited true negative samples used and nutrient deficiencies. The O-AET enables significant reduction in reagent volume, rapid turnaround, and compatibility with standard plate readers, making it cost-effective and scalable. This ATP bioluminescence-based platform provides a robust, reproducible, and high-throughput alternative to T-AET, with high potential to streamline product development and preservative screening in consumer care applications.

Global climate change and the rising prevalence of plant pathogens highlight the urgent need for sustainable strategies to enhance plant resilience. Microbial endophytes contribute to stress tolerance, yet their assembly is strongly influenced by host genetics. Here, we examined the roles of Arabidopsis thaliana pectin methylesterases PME12 and PME53, key enzymes in cell wall modification under heat stress, in shaping early endophyte colonization and modulating responses to Alternaria alternata, the causal agent of leaf blight. Heat stress promoted the enrichment of specific endophytes such as Rhodococcus ruber At-8, which exhibited strong antagonism toward A. alternata and enhanced seedling resistance, but provided limited protection in mature plants, indicating developmental-stage specificity in host-microbe interactions. Transcript analyses revealed that PME-mediated cell wall remodeling integrates heat and immune signaling by inducing HSFA2, HSP101, HSP18.2, APX2, GSTF8, PR1, and PDF1.2, thereby reinforcing stress adaptation and disease resistance. Collectively, these findings identify PME-dependent cell wall regulation as a pivotal mechanism linking environmental stress tolerance with endophyte-associated immunity.