Search Results (7,186)

Alfalfa mosaic virus (AMV) is a devastating plant pathogen with an extensive host range, yet effective control strategies remain limited. This study investigated the prophylactic efficacy and molecular mechanisms of two plant immune inducers, the Paecilomyces variotii extract DYDS and the antiviral agent Dufulin, against AMV infection in cowpea (Vigna unguiculata). Our results demonstrate that both agents possess potent antiviral activity, with inactivation, protective, and therapeutic efficacies all exceeding 21.00%. Notably, DYDS exhibited superior overall performance. RT-qPCR and immunofluorescence assays confirmed a significant downregulation of AMV coat protein (CP) expression in treated plants. Furthermore, exogenous application of these inducers mitigated chlorophyll loss and markedly augmented the activities of key defense enzymes’ activity, including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), polyphenol oxidase (PPO), and L-phenylalanine ammonia-lyase (PAL), peaking at 5 days post-inoculation. In silico molecular docking simulations further revealed that DYDS and Dufulin interact spontaneously with the AMV-CP, yielding binding free energies of −6.5 and −5.8 kcal/mol, respectively. Gene expression analysis indicated that these inducers trigger a robust immune response through the integrated activation of the salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) signaling pathways. Collectively, these findings suggest that DYDS and Dufulin provide a dual mode of action—direct viral inhibition and host immune priming—offering a promising and sustainable approach for the management of AMV in leguminous crops. Full article

Pseudomonas syringae pv. syringae (Pss) is the causal agent of bacterial canker, a disease that can result in yield losses, aerial tissue damage, and tree mortality in stone fruits worldwide. Peach, one of the major stone fruit crops, experiences significant yield losses and tree mortality attributed to bacterial canker in the United States. As the second-largest peach-producing state, South Carolina faces direct and significant impacts due to Pss. Early evaluations of peach scion responses to Pss infection have relied primarily on circumstantial field observations in rootstock trials. Although laboratory evaluations in peach have been reported, these studies primarily focused on pathogen virulence testing or small accession sets and did not establish a standardized, scalable detached twig protocol for systematic germplasm phenotyping. The absence of a clearly described laboratory assay has limited reproducible and large-scale evaluation of bacterial canker tolerance in peach. To address this gap, a detached dormant twig assay, previously developed for cherry, was adapted and optimized for peach. Dormant shoots from nine peach accessions were cut into 10 cm segments, surface-sterilized, and inoculated with a Pss suspension prepared in 10 mM MgCl₂ buffer or with the buffer alone. After six weeks of incubation, inner bark lesion size was evaluated visually and quantified using ImageJ. A newly developed visual rating scale was established and compared with quantitative lesion measurements. Spearman correlation analysis showed strong positive correlations between visual disease scores and ImageJ-based lesion measurements across two independent replicates (ρ = 0.80–1.00, p < 0.01), while shoot segment diameter showed weak-to-moderate negative correlations with disease severity. This adapted and consolidated dormant twig assay provides a practical, reproducible, and scalable method for phenotyping bacterial canker tolerance in peach and supports future germplasm screening and breeding efforts. Full article

Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot, has a significant impact on cabbage production worldwide. The goal of this research was to evaluate the effect of preventive foliar treatments with Bacillus velezensis strain RD-FC 88 on the primary and secondary metabolism of Xcc-infected cabbage cv. Futoški plants. Special attention was given to measuring metabolites’ changes, aiming to determine the influence of the applied biocontrol treatment on the development of plant immune response and resistance to pathogen. This study reports the first comprehensive biochemical and physiological analysis of the interaction between host plant, biocontrol strain and pathogen, thus providing novel insight into black rot management. Pathogen inoculation caused a significant decrease in the majority of measured metabolites, including most free amino acids (Gln, Ala, BCAA), phenolics, and glucosinolates. Preventive application of B. velezensis strain in Xcc-infected plants restored the levels of aromatic amino acids, Asp, Glu, Leu, Val, and Ala to control values. A similar pattern was observed in aliphatic glucosinolates sinigrin and glucoiberin, as well as for the indolic glucosinolate 4-methoxy-glucobrassicin. Additionally, increased accumulation of hydroxybenzoic acids, hydroxycinnamic acids, and kaempferol derivatives was also observed in the plants treated with the biocontrol strain and subsequently infected with Xcc, compared to plants solely infected with Xcc. The obtained results imply that the RD-FC 88 strain holds potential as an efficient priming agent, capable of stimulating cabbage cv. Futoški defense responses and enhancing its resistance to Xcc. Full article

The cactus pear (Opuntia spp.) is a crop of major economic and ecological importance in arid and semi-arid regions. However, with its domestication and intensification, symptoms of fungal diseases have begun to emerge in different cultivation areas. This study was conducted to identify the pathogenic fungi associated with symptoms observed on cladodes in different regions of Morocco and to evaluate the effectiveness of bacterial and fungal antagonists. The study enabled the isolation and identification of several fungal agents from symptomatic cladodes, namely Alternaria alternata, Alternaria tenuissima, Colletotrichum gloeosporioides, and Aspergillus tubingensis. Among these pathogens, A. alternata proved to be the most aggressive and was therefore selected for in vitro and in vivo antagonism assays. Twelve bacterial isolates belonging to the genera Bacillus and Pseudomonas, as well as one isolate of Trichoderma harzianum, were evaluated for their antifungal activity. All antagonists showed significant inhibitory effects against A. alternata in vitro preliminary assay. However, the bacterial isolates B. siamensis, B. halotolerans, and P. peli, as well as T. harzianum, exhibited the highest efficacy. This efficacy was confirmed through direct confrontation tests in vivo on one-year-old cladodes for the three bacterial isolates. In contrast, T. harzianum showed significant pathogenic potential on cladodes of O. ficus-indica and O. megacantha. Investigation of the mechanisms of action of the three most effective bacterial isolates revealed their ability to produce antifungal volatile organic compounds. Enzymatic analyses showed differential production of amylase, chitinase, cellulase and protease among the three isolates, while genes associated with the biosynthesis of antifungal lipopeptides were detected only in P. peli. Full article

Cedar virus (CedV), related to the highly pathogenic bat-borne henipaviruses, Hendra virus (HeV) and Nipah virus (NiV), is non-pathogenic in small animal models, likely due to the inability to produce interferon-antagonist proteins. We evaluated the pathogenesis of recombinant CedV (rCedV) in the African green monkey (AGM) model and determined if prior infection conferred cross-protective immunity against a lethal challenge with NiV Bangladesh (NiV-B) or HeV. AGMs infected with rCedV remained asymptomatic, with no clinical signs of disease or detectable viremia. The rCedV infected animals developed homologous neutralizing antibody responses that failed to cross-neutralize NiV-B or HeV. At 42 days post-rCedV infection, AGMs were challenged with a lethal dose of NiV-B or HeV, and prior infection with rCedV failed to protect against NiV-B challenge, with all animals succumbing to NiV-B. Similarly, rCedV infection did not confer consistent protection against HeV, with 2/4 animals succumbing to lethal HeV. These findings confirm that CedV is non-pathogenic in the AGM model of NiV and HeV infection, justifying its classification as a BSL-2 agent. The findings also demonstrate that rCedV does not elicit a cross-protective immune response to prevent lethal disease from either NiV-B or HeV highlighting significant immunological differences between CedV and the pathogenic henipaviruses. Full article

The re-emergence of alphaviruses (family Togaviridae), such as chikungunya virus, poses significant public health risks, with direct impact on quality of life and work productivity. There are no approved antiviral drugs for the treatment of infections with alphaviruses. Several alphaviruses are classified as risk group 3 agents which require handling in high-containment laboratories. To facilitate antiviral screening efforts against alphaviruses, we established a high-throughput antiviral screening assay using reporter Sindbis virus [SINV-GFP; expresses the green fluorescent protein] as a surrogate model for more pathogenic alphaviruses. The assay has strong reproducibility and was validated by reference small-molecule antivirals with various mechanisms of action. The use of high-content imaging as a readout, as demonstrated here, allows for high-throughput antiviral screening and provides a tool for early-stage antiviral discovery against emerging alphavirus threats at a lower biosafety level. Full article

Biofilm production by foodborne pathogens poses significant challenges to food safety and quality, leading to contamination, deterioration, and substantial economic losses for the food industry. Traditional biofilm control methods, such as chemical disinfectants, antibiotics, and preservatives, are sometimes ineffective against persistent biofilms, raising concerns about antimicrobial resistance and the accumulation of chemical residues. Lactic acid bacteria (LAB) have emerged as attractive natural biocontrol agents due to their ability to produce a wide range of antimicrobial secondary metabolites, including bacteriocins, organic acids, hydrogen peroxide, and biosurfactants. This paper thoroughly examines the effect of LAB and their metabolites in preventing and destroying biofilms generated by bacteria relevant to food systems, including Listeria monocytogenes, Salmonella enterica, Escherichia coli, and Pseudomonas spp. The processes causing LAB-mediated biofilm attenuation are thoroughly investigated, including competition for nutrients and adhesion sites, interference with quorum sensing (QS), and metabolic inhibition. Furthermore, recent breakthroughs in LAB-based techniques for food preservation and facility hygiene are discussed, including the creation of LAB-derived antimicrobial coatings, biosurfactant-based cleaning agents, and probiotic bio-coatings for industrial sanitation. The incorporation of nanotechnology has enhanced LAB applications by enabling the creation of LAB-mediated metallic nanoparticles and encapsulated formulations that improve metabolite stability and facilitate controlled release. The combination of LAB metabolites, natural preservatives, and eco-friendly materials in active packaging provides sustainable alternatives to synthetic chemicals. Overall, this review emphasizes the potential of LAB and their bioactive derivatives as environmentally friendly and practical tools for controlling biofilms and preserving food, thereby promoting safer food production systems and accelerating the food industry’s transition to green, sustainable technologies. Full article

Background: Immunomodulatory compounds can modify or regulate the immune responses. Given that vaccine-induced immune responses can vary in magnitude and durability depending on antigen properties and adjuvant selection. Immunomodulators that enhance antigen-specific immune responses with low toxicity may complement existing adjuvant systems. Recent studies indicate that adenosine receptor–mediated signaling can modulate dendritic cell (DC) function through mechanisms distinct from classical pathogen-associated molecular pattern (PAMP)-driven Toll-like receptor pathways. Methods: In this context, the present study comparatively evaluates poly-(lactic-co-glycolic acid) (PLGA) microparticle–encapsulated β-L-adenosine (BLA MPs) alongside established FDA-approved adjuvants to assess their immunomodulatory potential under limited-antigen conditions. FDA-approved PLGA was used to encapsulate BLA in combination with multiple viral antigens, including H1N1 influenza, Zika virus, and canine coronavirus, to enable sustained delivery, antigen protection, and efficient uptake by antigen-presenting cells. Results: Physicochemical characterization demonstrated uniform particle size distribution, a low polydispersity index, and a stable negative surface charge. Release studies showed more than 50% payload release within 12 h, with release kinetics best described by the Korsmeyer–Peppas model. Cytotoxicity evaluation using DC2.4 cells confirmed that BLA MPs were non-cytotoxic at concentrations up to 250 μg/mL. Comparative in vitro immunological assessments revealed that BLA MPs induced dendritic cell activation, including upregulation of antigen-presenting and co-stimulatory molecules, at levels largely comparable to those observed with Alum- and MF59-based formulations across multiple antigen groups. Nitric oxide production remained within comparable ranges, indicating balanced immunostimulatory activity without excessive inflammatory signaling. In select conditions, co-formulation of BLA MPs with MF59 further enhanced DC activation, supporting its role as a complementary immunomodulatory component. Conclusion: These findings align with previously reported adenosine-dependent pathways involved in DC maturation and antigen presentation. Overall, this comparative study demonstrates that PLGA-encapsulated β-L-adenosine functions as an effective immunomodulatory agent, with performance comparable to that of established FDA-approved adjuvants across diverse vaccine antigens. Further in vivo studies are warranted to evaluate dose dependency, cytokine profiles, and antibody responses to define its role within combinatorial vaccine adjuvant strategies. Full article

Aquaculture has evolved as one of the most dynamic industries in food production, representing the fastest-growing activity in meeting global food demand. Nevertheless, its rapid expansion is accompanied by significant challenges, including water pollution and the proliferation of pathogens that induce stress in aquatic organisms, leading to disease outbreaks and high mortality rates. To mitigate these problems, antibiotics and chemical agents are widely used to control infections. However, their excessive application results in residual contamination and promotes the emergence of drug-resistant bacterial strains. As a sustainable and environmentally friendly alternative, probiotics, prebiotics, and phytobiotics have attracted growing interest as substitutes for conventional chemotherapy in aquaculture. These functional feed additives enhance disease resistance and exhibit diverse bioactivities, such as antibacterial, antiviral, antifungal, and antiparasitic effects. Additionally, they improve growth performance, strengthen immune responses in cultured species, and contribute to better water quality. This review synthesizes current findings on the role of probiotics, prebiotics and phytobiotics in advancing sustainable aquaculture practices worldwide, while critically discussing their limitations, such as species-specificity, dose and duration responses, and potential long-term risks, thereby providing valuable insights to guide future research and innovation toward environmentally responsible and health-promoting solutions in the aquaculture industry. Full article

Bovine respiratory syncytial virus (BRSV) is a major viral pathogen associated with bovine respiratory disease (BRD), a leading cause of illness and economic loss in cattle worldwide. In June 2022, an acute respiratory outbreak occurred in a dairy herd in Photharam District, Ratchaburi Province, Thailand, affecting 25 of 103 cows (24.3%) and resulting in three deaths (2.9%). This study aimed to confirm BRSV as the etiological agent of the outbreak and to genetically and phylogenetically characterize Thai BRSV strains using partial G gene sequencing. Clinical signs included fever, nasal discharge, coughing, and subcutaneous emphysema. Nested reverse transcription-polymerase chain reaction (nested RT-PCR), a sensitive method for detecting viral RNA and targeting the F and G genes, confirmed BRSV in all samples. At the same time, bovine parainfluenza virus type 3 (BPIV-3), bovine viral diarrhea virus (BVDV), and bovine herpesvirus 1 (BoHV-1) were not detected. Phylogenetic analysis of partial G gene sequences showed that all Thai isolates clustered closely within subgroup III, with 100% nucleotide identity among themselves and 85.9–97.7% similarity to subgroup III strains from other countries. Amino acid alignment indicated conservation of key antigenic motifs, including the cysteine noose, with only minor substitutions compared to some foreign strains. This study provides the first genetic and phylogenetic characterization of BRSV in Thailand, highlighting the genetic stability of subgroup III and providing baseline molecular data to support regional surveillance, diagnostics, and vaccine strategies. Full article

Fowl adenovirus serotype 4 (FAdV-4) is the major causative agent of hydropericardium-hepatitis syndrome (HHS), a disease responsible for considerable economic losses in poultry production. Although inactivated and live-attenuated vaccines reduce mortality, continued outbreaks highlight the need to optimize vaccination strategies. To address these limitations, we developed and evaluated a bivalent subunit vaccine composed of recombinant hexon-L1 and fiber-2 proteins, two major antigenic determinants associated with neutralization and pathogenicity. The proteins were expressed in Escherichia coli, purified under native conditions, confirmed for purity and antigenicity, and emulsified into a water-in-oil formulation. Chickens were immunized with either 10 μg or 20 μg doses, boosted after 14 days, and challenged with the homologous virulent FAdV-4 strain SDLC202009. The 20 μg dose conferred complete survival, eliminated histopathological lesions, prevented viral detection in tissues by PCR and immunohistochemistry, and fully blocked viral shedding. Similarly, the 10 μg dose induced a good protection with only minor pathological differences compared to the group treated with 20 μg. These results demonstrate that a bivalent hexon-L1 and fiber-2 subunit formulation elicits strong, dose-dependent humoral and tissue-level protection against homologous FAdV-4 challenge under the conditions tested. The experimental design did not include a monovalent fiber-2 comparator; therefore, conclusions regarding the relative contribution of each antigen are not drawn. Full article

Background: The eco-friendly synthesis of silver nanoparticles (AgNPs) utilizing medicinal flora presents a viable strategy for the development of multifunctional agents exhibiting antimicrobial, antioxidant, anti-inflammatory, and anticancer properties. This investigation aims to elucidate the phytochemical composition of Calotropis gigantea and its contribution to the synthesis of CG-AgNPs that demonstrate efficacy against Helicobacter pylori and gastric cancer cell lines. Methods: The aqueous plant leaf extract of C. gigantea underwent comprehensive analysis via gas chromatography-mass spectrometry (GC-MS), identifying a total of 25 bioactive constituents, including oleic and oxalic acid derivatives. The fabrication and analysis of silver nanoparticles (AgNPs) were performed utilizing methodologies including ultraviolet-visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS), and assessments of zeta potential. Antibacterial efficacy was evaluated through methods including agar well diffusion, time-kill kinetics, and biofilm assays. The cytotoxic impact on AGS gastric cancer cells was investigated using MTT assays, DAPI staining, and acridine orange/ethidium bromide (AO/EtBr) staining techniques. The assessment of antioxidant potential was performed utilizing DPPH and ABTS assays. The anti-inflammatory properties were analyzed through protein denaturation and membrane stabilization tests. Results: CG-AgNPs exhibited a spherical morphology (11–17 nm) with commendable stability, denoted by using zeta potential analysis measurement of −30.2 mV. The antibacterial activity showed a significant inhibition zone of 16.00 ± 0.17 mm at a concentration of 50 µg/mL against H. pylori, in addition to notable biofilm disruption. The viability of AGS cells was reduced by 61% at a concentration of 100 micrograms per milliliter, with apoptosis being confirmed through relevant assays. The antioxidant potential varied from 18% to 83% (DPPH) and reached 74% (ABTS) at a concentration of 100 µg/mL. The anti-inflammatory assays indicated a BSA denaturation inhibition ranging from 45% to 80% and a membrane stabilization effect between 54% and 85%. Conclusions: CG-AgNPs exhibit substantial antibacterial, antioxidant, anti-inflammatory, and anticancer activities, underscoring their pharmaceutical potential, particularly for combating antibiotic-resistant pathogens and gastric malignancies. Full article

Importance: Uncomplicated urinary tract infections (uUTIs) are among the most common bacterial infections and are typically treated with existing oral antibiotics. In 2024–2025, the FDA approved two new oral agents, sulopenem etzadroxil/probenecid and gepotidacin, via expedited review pathways, for the treatment of uUTIs. Objective: To assess the clinical significance and regulatory evidence supporting FDA approval of sulopenem/probenecid and gepotidacin for uUTI, and to analyze the adherence of pivotal phase III trials to regulatory standards for approval and FDA guidelines. Design, Setting, and Participants: Comparative descriptive analysis of publicly available data from phase 3 randomized, double-blind, active-controlled clinical trials submitted to the FDA for approval. Pivotal phase III clinical trial data and FDA integrated reviews, guidance for the industry, and approved drug labels. Adult women with uUTI enrolled in pivotal phase III clinical trials, with subgroup analysis stratified by pathogen susceptibility to comparator antibiotics. Interventions: Sulopenem/probenecid was compared to ciprofloxacin and to amoxicillin/clavulanate and gepotidacin was compared to nitrofurantoin. Main Outcomes and Measures: Primary endpoints were clinical and microbiological responses assessed in the microbiologic modified intention-to-treat (micro-MITT) subjects. Safety outcomes and FDA regulatory determinations were also assessed. Results: Sulopenem/probenecid was inferior to ciprofloxacin and noninferior to amoxicillin/clavulanate in subjects with susceptible pathogens, and superior in subjects with resistant pathogens. Gepotidacin showed noninferiority to nitrofurantoin in one trial and superiority in another. Trials excluded randomized subjects, included post-randomization subgroup analyses, and enrolled control-arm subjects with resistant pathogens. Clinical cure rates were lower than historical comparators. Both new antibiotics had higher adverse event rates than controls. Conclusions and Relevance: Pivotal clinical trials for sulopenem/probenecid and gepotidacin for uUTI had significant design limitations and relied on surrogate endpoints of limited clinical interpretability, undermining reliability and clinical relevance. Future antibiotic development for uUTI should prioritize representative populations, standard-of-care comparators, clinically meaningful outcomes and robust, well-controlled trial designs to ensure meaningful clinical evidence of safety and efficacy. Full article

Lassa virus (LASV), a member of the Arenaviridae family, is the causative agent of Lassa fever (LF), an acute zoonotic hemorrhagic disease transmitted by rodents, characterized by high infectivity and mortality rates. Due to the nonspecific nature of early clinical symptoms, the development of rapid, sensitive, and specific diagnostic methods is critical for effective epidemic control. In this study, the Lassa virus glycoprotein complex (LASV-G) was selected as the target antigen. High-affinity rabbit monoclonal antibodies were generated using a single B-cell cloning approach, and an AlphaLISA (Amplified Luminescent Proximity Homogeneous Assay)-based homogeneous, no-wash detection system was established. Sixteen LASV-G-specific monoclonal antibodies were isolated through flow cytometric sorting, and the optimal antibody pair (56–24) was identified by AlphaLISA pairing and performance screening. The established AlphaLISA system exhibited a limit of detection (LOD) of 0.025 ng/mL, representing approximately a 30-fold increase in sensitivity compared with conventional Enzyme Linked Immunosorbent Assay (ELISA), while reducing the total assay time to less than 30 min. The coefficient of variation (CV) was below 8%, and no cross-reactivity was observed with Ebola, dengue, yellow fever, Zika, or influenza virus antigens. These findings demonstrate that the developed AlphaLISA assay possesses high sensitivity, rapid detection, and good tolerance to matrix effects, significantly improving the efficiency of early LASV antigen detection. This work provides a potential platform for the rapid on-site screening and epidemiological surveillance of highly pathogenic viruses. Full article

Phytoplasmas are obligate intracellular parasitic bacteria that infect over 1000 plant species globally, causing devastating diseases characterized by yellowing, witches’ broom, phyllody, and significant yield losses in economically important crops. The unculturable nature of these pathogens has historically hindered their study; however, advances in molecular biology and genomics have substantially accelerated progress over the past two decades. This review provides a comprehensive overview of current knowledge on phytoplasma diseases and control technologies. In terms of taxonomy, phytoplasmas are currently classified into 37 16Sr groups with over 150 subgroups based on 16S rRNA gene analysis, and approximately 50 ‘Candidatus Phytoplasma’ species have been formally named. Genomic studies have revealed that phytoplasmas possess highly reduced genomes (530–1350 kb) lacking many essential metabolic pathways, reflecting their obligate parasitic lifestyle. Regarding pathogenesis, secreted effector proteins such as SAP (Secreted Aster Yellows Witches’ Broom Protein), TENGU (tengu-su inducer), and SWP (Secreted Wheat Blue Dwarf Protein) manipulate plant hormone signaling and developmental processes, leading to characteristic disease symptoms. Detection technologies have evolved from traditional microscopy to molecular methods, including nested PCR, real-time quantitative PCR, loop-mediated isothermal amplification (LAMP), and CRISPR/Cas-based systems (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein), with AI-based image recognition and remote sensing emerging as promising tools for large-scale field monitoring. Integrated management strategies encompassing agricultural practices, insect vector control, biological control agents, induced resistance, and breeding for resistance are discussed. Finally, future research directions, including functional genomics, microbiome-based approaches, and precision agriculture technologies, are highlighted. This review aims to provide researchers and practitioners with a systematic reference for understanding phytoplasma biology and developing effective disease management strategies. Full article