Therapeutics that target the virulence of pathogens rather than their viability offer a promising alternative for treating infectious diseases and circumventing antibiotic resistance. In this study, we searched for anti-virulence compounds against Pseudomonas aeruginosa from Chinese herbs and investigated baicalin from Scutellariae radix as such an active anti-virulence compound. The effect of baicalin on a range of important virulence factors in P. aeruginosa was assessed using luxCDABE-based reporters and by phenotypical assays. The molecular mechanism of the virulence inhibition by baicalin was investigated using genetic approaches. The impact of baicalin on P. aeruginosa pathogenicity was evaluated by both in vitro assays and in vivo animal models. The results show that baicalin diminished a plenty of important virulence factors in P. aeruginosa, including the Type III secretion system (T3SS). Baicalin treatment reduced the cellular toxicity of P. aeruginosa on the mammalian cells and attenuated in vivo pathogenicity in a Drosophila melanogaster infection model. In a rat pulmonary infection model, baicalin significantly reduced the severity of lung pathology and accelerated lung bacterial clearance. The PqsR of the Pseudomonas quinolone signal (PQS) system was found to be required for baicalin’s impact on T3SS. These findings indicate that baicalin is a promising therapeutic candidate for treating P. aeruginosa infections.
Heat shock proteins (HSPs) play important biological roles, and they are implicated in bacterial response to environmental stresses and in pathogenesis of infection. The role of HSPs in P. aeruginosa, however, remains to be fully elucidated. Here, we report the unique role of HSP DnaJ in biofilm formation and pathogenicity in P. aeruginosa. A dnaJ mutant produced hardly any pyocyanin and formed significantly less biofilms, which contributed to decreased pathogenicity as demonstrated by reduced mortality rate in a Drosophila melanogaster infection model. The reduced pyocyanin production in the dnaJ mutant was a result of the decreased transcription of phenazine synthesis operons including phzA1, phzA2, phzS, and phzM. The reduction of biofilm formation and initial adhesion in the dnaJ mutant could be reversed by exogenously added pyocyanin or extracellular DNA (eDNA). Consistent with such observations, absence of dnaJ significantly reduced the release of eDNA in P. aeruginosa and addition of exogenous pyocyanin could restore eDNA release. These results indicate dnaJ mutation caused reduced pyocyanin production, which in turn caused the decreased eDNA, resulting in decreased biofilm formation. DnaJ is required for pyocyanin production and full virulence in P. aeruginosa; it affects biofilm formation and initial adhesion via pyocyanin, inducing eDNA release.
The effective healing of chronic wounds requires balancing antimicrobial activity with tissue regeneration. In this study, we developed a novel, eco-friendly synthesis method using Artemisia argyi extract to produce silver nanoparticles (AgNPs), addressing toxicity concerns associated with conventional chemical synthesis methods. Through optimization of multiple synthesis parameters, monodisperse spherical AgNPs with an average diameter of 6.76 ± 0.27 nm were successfully obtained. Plant-derived compounds from Artemisia argyi extract acted as efficient mediators for both reduction and stabilization, yielding nanoparticles with high crystallinity. The synthesized AgNPs exhibited potent antibacterial activity against both Gram-negative and Gram-positive bacteria, with minimum inhibitory concentrations of 8 μg/mL against Escherichia coli and 32 μg/mL against Staphylococcus aureus, while maintaining high biocompatibility with L929 fibroblasts at concentrations ≤ 8 μg/mL. When integrated into polylactic acid/collagen type I (PLA/Col1) nanofibrous matrices, the optimized 0.03% AgNPs/PLA/Col1 dressing significantly accelerated wound healing in a diabetic rat model, achieving 94.62 ± 2.64% wound closure by day 14 compared to 65.81 ± 1.80% observed in untreated controls. Histological analyses revealed a dual-functional mechanism wherein controlled silver ion release provided sustained antibacterial protection, while concurrently promoting tissue regeneration characterized by enhanced collagen deposition, reduced inflammation, and increased neovascularization. This innovative approach effectively addresses critical challenges in diabetic wound care by providing simultaneous antimicrobial and regenerative functions within a single biomaterial platform.
This study explores the efficient conversion of castor oil to sebacic acid utilizing iron oxide (Fe2O3) loaded on activated carbons as catalysts. Through a combination of saponification, acidification, and catalytic cracking, sebacic acid was produced with a notable yield improvement. The process involved using liquid paraffin as a thinning agent, overcoming the limitations of traditional toxic agents. The catalysts were prepared via adsorption-precipitation-calcination methods, with ultrasonication pretreatment to enhance iron adsorption on activated carbons. The chemical composition, structure, and morphology properties were investigated by different characterizations; such as scanning electron microscopy (SEM), thermogravimetric analysis (TG/DTG). Systematic investigations into the adsorption capacity, catalytic activity, and operational parameters like temperature, reaction time, and catalyst recycling were conducted. The optimized method achieved a sebacic acid yield of 83.4%, significantly higher than traditional methods (60.2%), with improved safety and environmental impact. The study provides valuable insights into sustainable and efficient sebacic acid production which is crucial for industrial applications in processing of castor oil.
A high-density mycelium-based biofoam (MBB) was firstly fabricated from agricultural residues through a two-step solid-state fermentation using Ganoderma lingzhi. The resulting biofoam exhibits a well-integrated porous architecture formed by an interconnected mycelial network, leading to enhanced structural integrity. Comprehensive characterization demonstrated improved physicochemical properties, including reduced lignocellulosic crystallinity, increased specific surface area, and a hierarchical mesoporous structure. MBB exhibits ultra-high compressive strength without premature failure and outstanding thermal insulation. Infrared imaging confirms significantly delayed heat penetration, with an insulation duration 2–3 times longer than reported biofoams and ~13 times longer than commercial insulation. Combined with stable hydrophobicity, long-term water resistance, low microbial load under standard conditions, and effective sound insulation comparable to commercial materials, this MBB—derived from renewable feedstocks and fully biodegradable—represents a highly sustainable and high-performance alternative to petroleum-based foams for building insulation and packaging applications.
The evolutionary arms race between phages and bacteria hinges on the discovery of counter-defensive strategies. In this study, it is found that Gp4.5, a protein encoded by the Klebsiella pneumoniae phage Kp84S, acts as a key anti-defense factor against a host toxin-antitoxin (TA) system. While gp4.5 deletion impaired phage lytic capacity, its conditional overexpression in the host triggered abortive infection, rendering cells resistant to phage predation. Mechanistically, RNA-seq analysis indicates that Gp4.5 silences the toxin gene higB2 and orchestrates a broad transcriptional rewiring of biofilm, and envelope pathways. This study unveils a dual-function phage protein that not only disarms a specific TA defense but also reprograms host physiology to favor lysis, providing a novel paradigm for phage adaptation and a target for therapeutic enhancement.