Search Results (513)

In intensive animal production, the overuse of antibiotics has exacerbated bacterial antimicrobial resistance and environmental pollution. Together with gut microbiota dysbiosis and recurrent disease outbreaks, these challenges severely constrain the sector’s high-quality development. Quorum sensing (QS), a cell-density-dependent bacterial communication mechanism, can be modulated through agents that specifically inhibit or activate QS circuitry to regulate microbial community functions. Such QS modulators possess notable advantages, such as environmental benignity and high target specificity, and thus offer innovative strategies to decrease antibiotic reliance, enhance production efficiency, and reduce environmental emissions. This review examines QS modulators sourced from plants, microorganisms, animals, and synthetic processes, while highlighting key challenges such as environmental interference, resistance development, high costs, and the lack of standardized biosafety evaluations. Future research should focus on enhancing specificity, stability, affordability, and safety, with an emphasis on rational design, synergistic systems, improved manufacturing processes, and multi-target modulators. This review may provide a theoretical basis for translating QS-regulation technologies into farm-level applications, thereby advancing sustainable animal production and antibiotic-free husbandry. Full article

Background: Plant essential oils are extensively utilized for their antimicrobial properties; however, the specific antifungal mechanisms of certain compounds are not well characterized. Geraniol, a naturally occurring monoterpene alcohol approved for use in foods, demonstrates potential efficacy against spoilage fungi, yet detailed mechanistic insights are lacking. Methods: In this study, we determined the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of geraniol against P. polonicum. We assessed the underlying mechanisms by evaluating membrane integrity, intracellular leakage, reactive oxygen species (ROS), antioxidant enzymes (superoxide dismutase [SOD], peroxidase [POD], catalase [CAT]), malondialdehyde (MDA) levels, ATP content, and ATPase activity. Inoculated yam slices were exposed to geraniol vapor, and we monitored sensory, physicochemical, enzymatic, and microbial parameters. Results: Geraniol exhibited a minimum inhibitory concentration/minimum fungicidal concentration (MIC/MFC) of 0.3 mL/L. It disrupted cellular membranes, induced leakage, generated ROS, and caused lipid peroxidation, leading to elevated levels of malondialdehyde (MDA). Additionally, geraniol activated antioxidant enzymes and impaired energy metabolism. Fumigation with geraniol dose-dependently delayed the deterioration of yam, reduced weight loss, preserved texture and color, inhibited polyphenol oxidase (PPO) and POD activities, enhanced CAT and SOD activities, lowered MDA levels, and suppressed bacterial growth. Conclusions: Geraniol inhibits P. polonicum through multiple mechanisms, including membrane disruption, oxidative stress, and interference with energy metabolism, thereby effectively preserving the quality of fresh-cut yam and demonstrating potential as a natural preservative. Full article

Background/Objectives: Microbial resistance to antibiotics has become a major global public health problem, threatening the effectiveness of current therapeutic strategies. The present study seeks to investigate natural compounds originating from fungal sources for their ability to interfere with efflux pump-mediated resistance in multidrug-resistant (MDR) bacteria, with the overarching goal of uncovering new candidates for antimicrobial therapeutic development. A chemical investigation of the ethanol extract of Termitomyces clypeatus was carried out to isolate and identify its constituents. Methods: Structural elucidation of the isolated metabolites was achieved through 1D and 2D NMR spectroscopy supported by mass spectrometric data. The crude extract and the purified compounds were then evaluated for their antibacterial activities individually, in the presence of an efflux pump inhibitor, and in combination with three antibiotics, using standardized microdilution assays. Results: Chromatographic separation of the extract yielded eleven known compounds, including three sphingolipids: (9Z,12Z)-N-(1,3,4-trihydroxyoctadecan-2-yl)octadeca-9,12-dienamide (1), 2-hydroxy-N-(1,3,4-trihydroxyoctadecan-2-yl)hexadecanamide (2), and cerebroside B (3); four steroids: ergosterol (4), cerevisterol (5), ergosterol peroxide (6), and 5α,6α-epoxy-(22E,24R)-ergosta-8(14),22-diene-3β,7α-diol (7); one alkaloid: piperine (8); one carbohydrate: D-mannitol (9); and two phthalates: dimethyl phthalate (10) and bis(2-ethylhexyl) terephthalate (11). GC–MS analysis led to the identification of eight fatty acid derivatives (12–19). Sub-fraction A, along with compounds 3, 4, and 8, exhibited moderate antibacterial activity against some tested strains, with MIC values of 64 μg/mL. These compounds were identified as substrates of bacterial efflux pumps, and their presence enhanced the antibacterial effects of ciprofloxacin, doxycycline, and amikacin. Conclusions: The findings of the present work indicate that Termitomyces clypeatus contains compounds with potential therapeutic value, as adjuvants that enhance the activity of conventional antibiotics. Full article

Globally, Mycobacterium tuberculosis (Mtb) remains the leading cause of death from a single infectious agent. The only licensed vaccine, Bacillus Calmette–Guérin (BCG), was developed over a century ago and does not provide consistent protection against pulmonary tuberculosis (TB). Efforts to develop more effective vaccines are hindered by an incomplete understanding of the correlates of protection and by the pathogen’s sophisticated immune-evasion strategies. Mtb systematically undermines host defenses, reprograms host cell biology, and interferes with cell–cell communication to establish a permissive niche and sustain chronic infection. An effective vaccine must elicit immune responses capable of overcoming these bacterial strategies across diverse host and pathogen backgrounds. Traditional approaches focused on boosting T cell responses have proven inadequate. In this review, we summarize innate and adaptive immune mechanisms that contain Mtb, examine how bacterial immune subversion and host–pathogen heterogeneity complicate vaccine design, and highlight emerging concepts and strategies to guide TB vaccine development. Full article

Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen frequently associated with chronic and biofilm-related infections, largely driven by quorum sensing (QS)-related genes/phenotypes. In this study, we investigated the antivirulence activity of an engineered M13-derived phage-display particle (P9b), selected for specific binding to P. aeruginosa, which acts as a non-lytic modulator of QS through specific binding to a bacterial surface target. P9b induced a transient delay in early planktonic growth, without affecting long-term proliferation. In contrast, P9b significantly reduced biofilm-associated metabolic activity and pyocyanin production, consistent with an effect on QS-regulated pathways. Transcriptional analysis revealed significant downregulation of key QS regulators (lasI, lasR, rhlI, and rhlR) and modulation of phenazine biosynthesis genes (phzM downregulation and phzS upregulation), suggesting interference with QS-dependent regulatory circuits. Notably, P9b retained binding capacity and antibiofilm activity across clinically relevant P. aeruginosa isolates. Overall, these findings indicate that P9b acts as a selective, non-lytic modulator of virulence-associated traits, attenuating QS-regulated phenotypes without bactericidal effects. This study supports the potential of engineered filamentous phages as targeted antivirulence platforms for the development of innovative strategies against persistent and biofilm-associated infections. Full article

Endocrine-disrupting chemicals (EDCs) are a diverse group of environmental pollutants capable of interfering with hormonal and immune system regulation. In recent years, increasing concern has been raised about the effects of chemicals, including bisphenols, phthalates, per- and polyfluoroalkyl substances (PFAS), insecticides, and parabens, on maternal and fetal health, primarily due to their widespread exposure in human populations. Pregnancy represents a critical window characterized by tightly regulated hormonal and immunological adaptations. Emerging evidence suggests that EDC exposure during this period may alter maternal microbiota, disrupt immune responses, and interfere with endocrine signaling. These changes may increase susceptibility to bacterial and viral infections, including bacterial vaginosis, urinary tract infections, and intrauterine infections, all of which are associated with adverse pregnancy outcomes. This review summarizes the current evidence on the sources and mechanisms of exposure to endocrine disruptors during pregnancy and examines the potential biological pathways linking endocrine disruption to the development of infections. Particular emphasis is placed on the interactions between immune regulation, hormonal signaling, and changes in the microbiome, which may contribute to increased susceptibility to infections. A deeper understanding of these complex mechanisms is critical to improve risk assessment, develop effective public health strategies, and ultimately protect maternal and fetal health in an environment of increasing chemical exposure. A literature search was conducted using PubMed/MEDLINE, Scopus, and Web of Science, including studies published up to January 2026. Full article

The evaluation of D- and L-lactic acid production by lactic acid bacteria is of critical importance, particularly for strains intended for use in infant and young child foods. Additionally, compliance with relevant regulatory standards necessitates the detection of D-lactic acid. Additionally, regulatory requirements exist in this regard. This study aimed to develop and validate a method for simultaneously measuring D-lactic acid and L-lactic acid produced by lactic acid bacteria. The method validation of the HPLC analysis was performed in terms of accuracy, precision, specificity, limit of quantification (LOQ), linearity, range, and robustness, and the measurement uncertainty was also evaluated. The method demonstrated a limit of detection (LOD) of 0.25 µg/mL and LOQ of 0.8 μg/mL for D-/L-lactic acid. For six validated bacterial strains, mean recoveries ranged from 93.50% to 105.37%, with intra-assay relative standard deviations (RSD) of 0.90–2.64% and inter-laboratory RSD of 2.56–10.16%. Excellent linearity, accuracy, and precision were observed across the concentration range of 0.8–200.0 μg/mL. Results confirmed no interference from culture media batch variations, and sample stability was maintained for 48 h. Additionally, relative expanded uncertainties were determined as 10.48% and 7.64%. The developed method was suitable for the identification and quantification of D- and L-lactic acid in lactic acid bacteria fermentation broth samples. This method was applicable for assessing the production of D-/L-lactic acid by food cultures. Full article

Euproctis pseudoconspersa is a devastating pest in Camellia oleifera plantations, necessitating the development of sustainable molecular intervention strategies. This study targeted the chitin synthase A gene (EpCHSA) to evaluate and compare the RNA interference (RNAi) efficacy of dsRNA synthesized via the T7 in vitro transcription system and the Escherichia coli HT115 (DE3) expression system. The EpCHSA gene (2199 bp ORF) was cloned and characterized, exhibiting peak expression during the fourth-instar stage, and predominantly in the head tissues of fifth-instar larvae. Bioassays demonstrated that larvae fed with 500 ng/μL in vitro synthesized dsRNA exhibited continuous gene silencing for five days, reaching a maximum efficiency of 68.1%. Conversely, treatment with 100× concentrated bacterial broth (5000 ng/μL) elicited a superior silencing effect of 79.3% within 24 h. Furthermore, the bacterial treatment group reached a 14-day mortality rate of 46.66%, significantly higher than the in vitro group (38.33%). Both methods induced severe phenotypic abnormalities, including molting failure and pupal malformation. These findings conclude that the E. coli expression system offers a cost-effective and highly potent platform for dsRNA production. This research provides a critical technical foundation and promising application prospects for the field-scale management of E. pseudoconspersa utilizing RNAi-based biopesticides. Full article

Aphids are major agricultural pests worldwide, causing crop damage both through direct piercing-sucking feeding and the transmission of plant viruses. Their multistage life cycle, unique developmental physiology, plasticity in developing pesticide resistance, and multifaceted interactions with host plants and bacterial endosymbionts make effective control particularly challenging. In this review, we summarize the current toolbox available for aphid control across major crop systems, including chemical pesticides, biological agents, plant resistance, cultural practices, biorational control, and emerging strategies such as RNA interference (RNAi) and symbiosis-targeted approaches. Rather than providing an exhaustive survey of the literature, we draw on conceptual and illustrative studies to critically evaluate the strengths and limitations of each control strategy. Finally, we outline future directions for aphid control, highlighting the potential of modern technologies, such as artificial intelligence (AI), synthetic biology, data-driven analytics, and CRISPR-based genome editing, to expand and improve existing control options. Full article

C. burnetii (Cb) is an obligate intracellular bacterial pathogen that replicates within alveolar macrophages following aerosol infection. Unlike most intracellular bacteria, Cb establishes a lysosome-derived replicative niche (Coxiella-containing vacuole or CCV) through the action of its Type IVB secretion system (T4BSS). This system translocates a large repertoire of effector proteins into the host cytoplasm after phagosome acidification. These effectors interfere with diverse signaling pathways to co-opt host processes, such as vesicle trafficking, ubiquitylation, gene expression and lipid metabolism, promoting pathogen survival without triggering robust proinflammatory signaling or host cell death pathways. This effector-triggered immune silencing is particularly unique given the central role of macrophages as innate immune sentinels. In this review, we examine Cb T4BSS effectors that have been characterized as central determinants of innate immunity modulation. We discuss innate immune sensing pathways potentially engaged during infection, including Toll-like receptors, NOD-like receptors, RIG-I-like receptors, inflammasomes, and interferon signaling pathways, and highlight evidence indicating that these pathways are actively suppressed. Emphasis is placed on effector-mediated regulation of NF-κB signaling, type I interferon responses, and inflammasome activation. Finally, we address unresolved questions related to effector-triggered immunity, redundancy in immune suppression, and discrepancies between in vitro and in vivo infection models. Full article

Modification of PLA with functional nanoparticles is a promising approach for imparting new properties to the material. In this work, titanium nanoparticles (Ti NPs) and titanium dioxide nanoparticles (TiO₂ NPs) were synthesized by laser ablation and characterized by dynamic light scattering, spectrophotometry, and transmission electron microscopy. The average hydrodynamic diameter of Ti NPs was 12 nm, while that of TiO₂ NPs was 24 nm; both dispersions possessed a positive zeta potential (23–27 mV) and spherical morphology. L-PLA composite films containing 0.1 wt.% Ti NPs or TiO₂ NPs were obtained by solution casting. Atomic force and modulation-interference microscopy confirmed the uniform distribution of nanoparticles within the polymer matrix, although partial aggregation was observed. The introduction of TiO₂ NPs increased the water contact angle. Mechanical testing revealed a significant reinforcing effect: the addition of 0.1 wt.% NPs increased the Young’s modulus by 62–68% and the ultimate tensile strength by 16–18% while maintaining a ductile fracture pattern with elongation at break up to ~8%. Both types of composites generated reactive oxygen species (ROS) in aqueous solutions: Ti NPs increased H₂O₂ production by 5.5 times and TiO₂ NPs by 4.9 times, and they also induced the formation of hydroxyl radicals. The accumulation of 8-oxoguanine in DNA and long-lived oxidized protein species confirmed the materials’ ability to cause oxidative damage to biomacromolecules. For E. coli, growth inhibition reached 40.5% (for composites with Ti NPs) and 71% (for composites with TiO₂ NPs). The effect was even more pronounced for S. aureus, where inhibition levels were approximately 70% and 80%, respectively; flow cytometry confirmed the strong bactericidal effect, showing that materials containing TiO₂ NPs increased the proportion of dead cells to 25% for E. coli and ~68% for S. aureus. Cytotoxicity assessment on human fibroblasts (HSF) demonstrated the high biocompatibility of neat L-PLA and composites with Ti NPs (viability > 95%) and with TiO₂ NPs (viability ~93%). The obtained results indicate that L-PLA-based composites with Ti NPs and TiO₂ NPs exhibit pronounced ROS-mediated antibacterial activity without additional UV irradiation. These findings position these materials as highly promising candidates for active biodegradable food packaging to extend shelf-life and for biomedical devices, such as wound dressings and implants, where reducing the risk of bacterial colonization is critical. Full article

Background/Objectives: Bordetella bronchiseptica is a Gram-negative bacterium that, either acting alone or in concert with other bacterial or viral pathogens, is a major cause of the canine infectious respiratory disease (CIRD) complex in dogs. Most currently available vaccines are given intranasally or orally and, whilst providing satisfactory reduction in disease severity, can be difficult to use especially in aggressive or anxious dogs. Whilst a small number of injectable B. bronchiseptica vaccines have been developed, little is known about their characteristics with regard to the age at first vaccination, the onset of immunity, duration of immunity, induction of antibody responses, concurrent use with the core vaccines used in most dogs, efficacy in the face of maternally derived antibodies (MDAs) or existing immunity and safety in pregnant animals. Here we describe the development of a safe and efficacious injectable B. bronchiseptica vaccine that utilises a novel process to purify fimbriae. Methods: The fimbrial antigen was formulated with a vitamin E-based oil-in-water adjuvant known to be safe in dogs (Nobivac^® Respira Bb). To evaluate dose response, thirty-nine naïve 5–6-week-old Beagle puppies were allocated to four groups and vaccinated subcutaneously with Nobivac^® Respira Bb at 69 U, 25 U, and 7 U (with a booster at two weeks). All groups were challenged with B. bronchiseptica two weeks after the booster. To evaluate the onset of immunity at 5–6 weeks of age, twenty-one naïve Beagle dogs were split into two groups: group 1 received Nobivac Respira Bb (88 U/dose) plus Nobivac DHPPi and Nobivac L4; group 2 received DHPPi and L4 only. Both groups were challenged with B. bronchiseptica two weeks after the second vaccination. Safety in pregnancy was evaluated by vaccinating pregnant dams and monitoring whelping outcomes and puppy health. Protection in puppies with maternally derived antibodies (MDAs) was studied in 28 pups (11 MDA-negative and 17 MDA-positive from vaccinated and unvaccinated dams). Pups were vaccinated at 5–6 weeks; one group remained unvaccinated to monitor MDA kinetics. All puppies were challenged with B. bronchiseptica at 19 weeks, after MDAs became undetectable. Serology was monitored throughout; daily clinical observations and nasal swabs post-challenge assessed protection and bacterial shedding. Results: Nobivac Respira Bb (MSD Animal Health), was safe for use in 5–6-week-old puppies alongside other Nobivac core canine vaccines without vaccine interference. The vaccine has an onset of immunity of two weeks and significantly reduces both the clinical signs of B. bronchiseptica-induced disease and bacterial excretion into the environment. Furthermore, the vaccine is equally efficacious in puppies with maternally derived antibodies derived from vaccinated dams and can be used safely in pregnant bitches. Conclusions: This vaccine represents a convenient, safe and efficacious alternative to vaccines delivered via the oral or intranasal routes and is a positive addition to the range of vaccines targeted at reducing disease induced by B. bronchiseptica. Full article

Exogenously induced RNA interference (exoRNAi) is a powerful biotechnology tool for precise gene regulation. The plant chalcone synthase (CHS) gene serves as a valuable model for molecular biology due to its central role in flavonoid biosynthesis. However, there are currently very few studies addressing the advantages and disadvantages of in vitro (enzymatic) or in vivo (bacterial) methods for producing double-stranded RNA (dsRNA) for exogenous application. This study aims to optimize and compare the two methods for producing dsRNAs targeting the Arabidopsis thaliana CHS gene: enzymatic synthesis in vitro using a commercial kit and bacterial synthesis in vivo using an engineered E. coli HT115 (DE3) system. Bacterial synthesis conditions were optimized with respect to IPTG concentration and cultivation time, and the resulting dsRNA preparations were purified and quality-controlled. Their biological activities were assessed by treating A. thaliana plants and analyzing the effects on AtCHS gene expression and flavonoid production using qRT-PCR and HPLC-MS. The results demonstrated that purified AtCHS-dsRNA from both methods effectively suppressed AtCHS expression and downstream flavonoid biosynthetic gene expression, leading to significant reductions in anthocyanins and flavanols. This study confirmed the efficacy of exogenous dsRNAs in regulating plant metabolic pathways and provided a comparative analysis of dsRNA synthesis methods, highlighting their benefits and limitations for practical applications in plant biology and protection. Full article

Streptococcus parauberis is a major pathogen responsible for streptococcosis in both marine and freshwater fish species, causing substantial economic losses in aquaculture. The increasing prevalence of multidrug resistance has highlighted the urgent need for alternative disease control strategies. Interference with bacterial quorum sensing (QS) systems represents a promising approach. This study aimed to identify and biochemically characterize an Rgg-family transcriptional regulator and evaluate its potential as a target for quorum sensing-related regulatory interference in vitro. We hypothesized that this Rgg regulator may function as a quorum sensing-associated transcription factor capable of promoter binding and modulation by small molecules. Bioinformatic analyses were used to identify the rgg gene encoding an Rgg-family transcriptional regulator and predict its structural features. The gene was cloned, heterologously expressed, and purified. Promoter binding activity was examined using electrophoretic mobility shift assay (EMSA), and key amino acid residues were identified through site-directed mutagenesis. The inhibitory effect of the cyclic peptide cyclosporin A (CsA) on Rgg-promoter binding was further assessed. The rgg gene (864 bp) encoding a 287-amino-acid protein (34.1 kDa) was successfully identified and expressed. Purified Rgg specifically bound to its own promoter region in a concentration-dependent manner. Mutations at conserved arginine residues R12 and R15 within the helix-turn-helix DNA-binding domain abolished promoter binding activity. Furthermore, CsA disturbed Rgg-promoter binding in a dose-dependent manner. This study provides the first in vitro characterization of an Rgg-family transcriptional regulator in fish-derived S. parauberis. The findings expand current understanding of Rgg-family regulators potentially associated with quorum sensing in aquatic streptococci and provide a preliminary basis for further investigation of quorum sensing-related regulatory interference strategies for controlling streptococcal diseases in aquaculture. Full article

Salmonella enteritidis (SE) is recognized as a primary etiological agent of foodborne infection and food poisoning. Selective and sensitive determination of SE in animal-derived products is of great importance for ensuring safety in the food industry. Here, we report a highly sensitive and specific competition assay for detecting SE in eggs without interference from background fluorescence, by using persistent luminescent nanoparticles (PLNPs) as luminescent probes in combination with aptamer recognition and magnetic separation. Initially, the SE-specific aptamer (SEapt), as previously reported, was conjugated onto the surface of Fe₃O₄ magnetic nanoparticles to serve as both the recognition and separation unit. Meanwhile, the ZnGa₂O₄:Cr (PLNPs) were functionalized with the aptamer-complementary DNA (cDNA), serving as the PL signal generator. The constructed PL aptasensor is composed of the aptamer-conjugated MNPs (MNPs-SEapt) and cDNA-functionalized PLNPs (PLNPs-cDNA), integrating the merits of the long-lasting luminescence of PLNPs, the magnetic separation ability of MNPs and the selectivity of the aptamer. This integration offers a promising approach for autofluorescence-free determination of SE in food samples. The proposed aptasensor exhibited excellent linearity in the range from 1.0 × 10²–1.0 × 10⁷ CFU mL⁻¹ with a limit of detection as low as 32 CFU mL⁻¹. The precision for 11 replicate determinations of 1.0 × 10³ CFU mL⁻¹ SE was 3.4% (relative standard deviation). The developed aptasensor achieved recoveries ranging from 98.8% to 102.8% for the determination of SE in the presence of common foodborne bacterial interferents. The method was successfully applied to the analysis of Salmonella genus in egg samples. In principle, the proposed platform may be adapted to other food matrices by substituting the target-specific aptamer, pending target-dependent optimization and validation. Full article