Search Results (117)

Azospirillum is a well-studied genus of plant growth-promoting rhizobacteria (PGPR) and one of the most extensively researched diazotrophs. This genus can colonize rhizosphere soil and enhance plant growth and productivity by supplying essential nutrients to the host. Azospirillum–plant interactions involve multiple mechanisms, including nitrogen fixation, the production of phytohormones (auxins, cytokinins, indole acetic acid (IAA), and gibberellins), plant growth regulators, siderophore production, phosphate solubilization, and the synthesis of various bioactive molecules, such as flavonoids, hydrogen cyanide (HCN), and catalase. Thus, Azospirillum is involved in plant growth and development. The genus Azospirillum also enhances membrane activity by modifying the composition of membrane phospholipids and fatty acids, thereby ensuring membrane fluidity under water deficiency. It promotes the development of adventitious root systems, increases mineral and water uptake, mitigates environmental stressors (both biotic and abiotic), and exhibits antipathogenic activity. Biological nitrogen fixation (BNF) is the primary mechanism of Azospirillum, which is governed by structural nif genes present in all diazotrophic species. Globally, Azospirillum spp. are widely used as inoculants for commercial crop production. It is considered a non-pathogenic bacterium that can be utilized as a biofertilizer for a variety of crops, particularly cereals and grasses such as rice and wheat, which are economically significant for agriculture. Furthermore, Azospirillum spp. influence gene expression pathways in plants, enhancing their resistance to biotic and abiotic stressors. Advances in genomics and transcriptomics have provided new insights into plant-microbe interactions. This review explored the molecular mechanisms underlying the role of Azospirillum spp. in plant growth. Additionally, BNF phytohormone synthesis, root architecture modification for nutrient uptake and stress tolerance, and immobilization for enhanced crop production are also important. A deeper understanding of the molecular basis of Azospirillum in biofertilizer and biostimulant development, as well as genetically engineered and immobilized strains for improved phosphate solubilization and nitrogen fixation, will contribute to sustainable agricultural practices and help to meet global food security demands. Full article

Antibiotic overuse has contributed to the emergence of multidrug-resistant (MDR) bacteria, posing a serious public health threat. Pets may act as reservoirs of MDR bacteria, with the potential to transmit these pathogens to humans. This study aimed to identify probiotic alternatives to antibiotics by isolating and evaluating lactic acid bacteria (LAB) from feline milk. In addition to conventional in vitro assessments such as growth kinetics, adhesion ability, safety, and antipathogenic activity, this study also evaluated the antioxidant capacity and production of beneficial metabolites. Three LAB strains were isolated from feline milk, including two strains of Lactobacillus plantarum (M2 and M3) and one strain of Weissella confusa (M1). Resistance assays revealed that strains M2 and M3 exhibited high survival rates under stress conditions, including exposure to bile salts, acidic environments, artificial intestinal and gastric juice. Notably, strain M3 demonstrated strong auto-aggregation ability (73.39%) and high hydrophobicity toward trichloromethane (62.16%). It was also nonhemolytic and susceptible to various β-lactam antibiotics. Furthermore, strain M3 exhibited potent antimicrobial activity in both co-aggregation and Oxford cup assays. Overall, L. plantarum M3 displayed superior probiotic properties, suggesting its potential as an adjunct or alternative to antibiotics in managing MDR bacterial infections in cats. Full article

Trichoderma harzianum, a prominent biocontrol microorganism, often exhibits restricted colonization efficiency in nutrient-poor soil, thus reducing its biocontrol effectiveness. This study investigated the impact of vitamin C industrial fermentation byproduct (residue after evaporation, RAE), which is recognized for enhancing plant growth and stress tolerance, on the colonization ability and anti-pathogenic fungi activity of T. harzianum through in vitro and pot experiments. In vitro experiments demonstrated that RAE and its main component (2-keto-L-gulonic acid, 2KGA) significantly enhanced biomass and spore production (41.44% and 158.46% on average) of two T. harzianum strains in an oligotrophic medium (1/5 PDA). In a more nutrient-limited medium (1/10 PDA), RAE significantly increased the inhibition rates of T. harzianum S against Fusarium graminearum, Botrytis cinerea, and Alternaria alternata by 6.12–7.77%. Pot experiments further revealed that, compared with T. harzianum application alone, the combined application of RAE and T. harzianum S, (1) significantly elevated T. harzianum S abundance by 23.77% while significantly reducing B. cinerea abundance by 33.78% in rhizosphere soil; (2) significantly improved the content of soil available phosphorus (147.63%), ammonium nitrogen (60.05%), and nitrate nitrogen (32.19%); and (3) significantly improved the superoxide dismutase activity (17.39%) and fresh weight of tomato plants (130.74%). Correlation analysis revealed that there were significant positive correlations between T. harzianum S abundances/plant biomass and RAE, and significantly negative correlations between B. cinerea abundance and T. harzianum S/plant biomass/peroxidase activity. Collectively, RAE effectively promoted the growth of T. harzianum and pathogen suppression ability, while improving soil fertility and tomato biomass. This study offers novel insights into RAE’s agricultural application for plant disease control while supporting the sustainable development of vitamin C production. Full article

The development of antimicrobial resistance drives the search for molecules capable of inhibiting bacterial virulence. Fungi of the Basidiomycota phylum constitute an important source of compounds with antimicrobial activity. The present paper describes a new species named Fulvifomes mexicanus sp. nov. based on morphological and phylogenetic analyses. The methanolic extract of basidiome of this fungus inhibited the motility of Pseudomonas aeruginosa ATCC 9027 and the production of violacein by Chromobacterium violaceum CV026. The metabolomic study of the extract by liquid chromatography–high-resolution electrospray ionization mass spectrometry (LC-HRESIMS) and molecular networking analyses revealed the presence of a complex composition of metabolites including hispidin derivatives, terpenoids, phenols, furanones, alkylglycerols, pyrones, and γ-butyrolactones, among others. Overall, this work represents the first chemical and biological study of a new species of Fulvifomes mexicanus as a source of antipathogenic metabolites for the development of novel antimicrobial agents. Full article

Background/Objectives: Wine pomace is a rich source of bioactive phenolic compounds with potential health benefits. This study aimed to evaluate the antipathogenic and antioxidant properties of ethanol and ethyl acetate extracts from wine pomace of three grape varietals (Tannat, Bonarda, and Malbec) to explore their potential as natural alternatives for mitigating bacterial virulence in Pseudomonas aeruginosa. Methods: Successive exhaustion extractions were performed using solvents of increasing polarity (ethyl acetate and ethanol). The phenolic content was quantified, and the antioxidant activity was evaluated using standard assays. The antipathogenic activity against P. aeruginosa was assessed by measuring biofilm formation, elastase and protease activity, pyocyanin production, and swarming motility. Quorum sensing (QS) inhibition was tested using a violacein production assay in Chromobacterium violaceum. Results: Ethanol was more effective at extracting phenolic compounds, with Tannat exhibiting the highest total phenolic content (162.5 µg GAE/mg). HPLC-DAD analysis identified 16 phenolic acids, 18 flavonoids, and 3 stilbenes across the extracts. The ethanol extracts showed strong antioxidant activity (phosphomolybdenum reducing capacity 67–128 μg AAE/mg, ABTS^•+ scavenging 37–71 µg/mL, Fe³⁺ reducing power 31–68 µg/mL) and inhibited biofilm formation (up to 61%), elastase (up to 41%), and protease (up to 46%) activities in P. aeruginosa. The extracts also reduced pyocyanin production (up to 78%) and swarming motility (up to 68%), suggesting interference with QS. Moreover, the extracts inhibited violacein production in C. violaceum, confirming QS inhibition (up to 26%). Conclusions: Among the extracts, ethanol-extracted Tannat pomace showed the most substantial antipathogenic and antioxidant activities. The results add value to wine pomace by suggesting its use as natural extracts rich in phenolic compounds, capable of controlling the bacterial virulence of Pseudomonas aeruginosa without promoting the development of resistance. Full article

Lactic acid bacteria are commonly present in various sources and possess significant probiotic properties. They can inhibit pathogenic bacteria and fungi simultaneously, making them promising candidates as bio-preservatives. This study investigated two potential probiotic strains: Lactiplantibacillus plantarum LR5-2 (isolated from fermented meat products) and Lacticaseibacillus rhamnosus SQ63 (isolated from infant feces). The study evaluated their aggregation ability, anti-pathogenic activity, safety, and tolerance to gastrointestinal conditions, phenol, and bile salts. Additionally, their biological control potential against Penicillium expansum on fresh grapes was assessed. The results demonstrated that both strains exhibited high survival rates under extreme gastrointestinal conditions, enhanced Auto-aggregation, co-aggregation, and hydrophobicity. They displayed strong antioxidant activity and significant antibacterial effects against 11 pathogenic fungi and foodborne pathogens. Biosafety testing revealed that both strains are sensitive to most antibiotics, do not produce biogenic amines, and exhibit no hemolytic or DNase activity. In grapes, L. plantarum LR5-2 and L. rhamnosus SQ63 significantly reduced the incidence and disease index of P. expansum infection. In conclusion, the characterization analysis and bio-preservation experiments revealed that LR5-2 and SQ63 have strong potential as probiotics and bio-preservatives. Full article

Lactobacillus, a genus of lactic acid bacteria, is known to coexist symbiotically in the female vaginal microbiota and has gained attention as a potential probiotic with benefits for female reproductive health. This study aimed to evaluate the probiotic potential of Lactobacillus gasseri BELG74(BELG74), isolated from the vaginal microbiota of Korean women, in promoting vaginal health through growth ability, pH reduction, lactic acid production, and antimicrobial activity. Among 36 Lactobacillus gasseri strains, BELG74 demonstrated the highest growth capacity at 1.84 × 10⁹ CFU/mL and the lowest pH of 3.84. BELG74 produced the most lactic acid at a concentration of 20.12 g/L, which correlated with anti-pathogenic activity against Gardnerella vaginalis, Fannyhessea vaginae, and Candida albicans of more than 90%. It also showed high acid resistance (92.2%) and bile resistance (25.3%), ensuring its survival through the gastrointestinal tract. Furthermore, BELG74 exhibited strong biofilm formation and adhesion capacity of 28.7% to HeLa cells, making it effective in colonizing the vaginal environment and suppressing pathogenic bacteria. The reduction of IL-1β by 63% suggested anti-inflammatory effects. Additionally, BELG74 effectively neutralized trimethylamine and ammonia by over 99.9%, suggesting its ability to reduce unpleasant vaginal odors. These findings indicate that BELG74 could be a promising probiotic for improving vaginal health, with further clinical studies needed to confirm these benefits. Full article

Ants as social insects live in groups, which increases the risk of contagious diseases. In response to the threat of pathogens, ants have evolved a variety of defense mechanisms, including incorporating antimicrobial chemicals into nest material for nest hygiene. Crematogaster rogenhoferi is an arboreal ant, building its nest using plant tissues. It is still unclear how C. rogenhoferi is protected against pathogens in its nest. Two main chemicals, 2,2′-methylenebis[6-(1,1-dimethylethyl)-4-methyl-phenol] (MP) and lup-20(29)-en-3-one (LP), isolated from nest materials of C. rogenhoferi were used to investigate ants’ anti-pathogenic activity against the entomopathogenic fungus Beauveria bassiana and the entomopathogenic bacteria Serratia marcescens. The results showed that MP and LP can inhibit the growth of B. bassiana through direct contact and fumigation. However, neither MP nor LP had any negative effect on S. marcescens growth. Subsequent analysis showed that MP was found in both the abdomen part and the head part of C. rogenhoferi workers, and LP was not detected in C. rogenhoferi workers. Since LP is a common plant secondary metabolite, it is implied that LP may originate from the plant tissue of C. rogenhoferi nest materials. Our results showed that C. rogenhoferi capitalizes on its own antimicrobial chemicals and probably the chemical defenses which have evolved in plants to protect itself against pathogens. Full article

A new generation of food packaging materials, centered on green solutions, is currently being developed in labs basing these materials on underused secondary industrial food by-products which have the ability to reduce the amount of petroleum-based packaging generated in order to minimize environmental harm and food by-products while ensuring food quality and safety. This study presents a sustainable biopolymeric combination based on bacterial nanocellulose grafted in yeast films, its potential to improve matrices properties, and the influence of plasticizer and emulsifier concentrations on mechanical properties, volatile fingerprint, and antimicrobial activity of films. Yeast films with 1.00% glycerol and 1.00% Tween 80, functionalized with a 2.00% mixture of cinnamon–lavender essential oils and with 2.00% bacterial cellulose produced from SCOBY presented improved mechanical properties compared to the control and exerted antipathogenic activity against Listeria monocytogens, Staphylococcus aureus, and Escherichia coli. Yeast films with grafted bacterial cellulose could be a sustainable food packaging solution for future applications. Full article

The mRNA-binding protein KSRP (KH-type splicing regulatory protein) is known to modulate immune cell functions post-transcriptionally, e.g., by reducing the mRNA stability of cytokines. It is known that KSRP binds the AU-rich motifs (ARE) that are often located in the 3′-untranslated part of mRNA species, encoding dynamically regulated proteins as, for example, cytokines. Innate myeloid immune cells, such as polymorphonuclear neutrophils (PMNs) and macrophages (MACs), eliminate pathogens by multiple mechanisms, including phagocytosis and the secretion of chemo- and cytokines. Here, we investigated the role of KSRP in the phenotype and functions of both innate immune cell types in the mouse model of invasive pulmonary aspergillosis (IPA). Here, KSRP^−/− mice showed lower levels of Aspergillus fumigatus conidia (AFC) and an increase in the frequencies of PMNs and MACs in the lungs. Our results showed that PMNs and MACs from KSRP^−/− mice exhibited an enhanced phagocytic uptake of AFC, accompanied by increased ROS production in PMNs upon stimulation. A comparison of RNA sequencing data revealed that 64 genes related to inflammatory and immune responses were shared between PMNs and MACs. The majority of genes upregulated in PMNs were involved in metabolic processes, cell cycles, and DNA repair. Similarly, KSRP-deficient PMNs displayed reduced levels of apoptosis. In conclusion, our results indicate that KSRP serves as a critical negative regulator of PMN and MAC anti-pathogen activity. Full article

New quaternary ammonium derivatives (quats) based on apple pectin (PA) were synthesized by the chemical modification of native polysaccharides with various quaternization mixtures containing epichlorohydrin (ECH) and a tertiary amine. Pectin derivatives (QPAs) were studied by elemental analysis, conductometric titration, Fourier-transform infrared spectroscopy (FTIR), and ¹³C nuclear magnetic resonance (¹³C NMR). Viscosity measurements enabled the evaluation of the viscosity average molar mass (M_v) for the unmodified polysaccharide, as well as its intrinsic viscosity ([η]) value. Dynamic light scattering (DLS) analysis revealed that the PA and its quats formed aggregates in an aqueous solution with either a unimodal (PA) or bimodal (QPAs) distribution. Scanning transmission electron microscopy analysis (STEM) of the PA and its derivatives demonstrated the presence of individual polymeric chains and aggregates in aqueous solution, with the smallest sizes being specific to amphiphilic polymers. Thermal stability, as well as wide-angle X-ray diffraction (WAXD) studies, generally indicated a lower thermal stability and crystallinity of the QPAs compared with those of the PA. Antipathogenic activity demonstrated that the PA and its derivatives exhibited effectiveness against S. aureus ATCC 25923 bacterium and C. albicans ATCC 10231 pathogenic yeast. Full article

Pigeon pea (Cajanus cajan (L.) Millsp.) is a traditional Chinese medicinal plant widely utilized in folk medicine due to its significant pharmacological and nutritional properties. Cajaninstilbene acid (CSA), a stilbene compound derived from pigeon pea leaves, has been extensively investigated since the 1980s. A thorough understanding of CSA’s mechanisms of action and its therapeutic effects on various diseases is crucial for developing novel therapeutic approaches. This paper presents an overview of recent research advancements concerning the biological activities and mechanisms of CSA and its derivatives up to February 2024. The review encompasses discussions on the in vivo metabolism of CSA and its derivatives, including antipathogenic micro-organisms activity, anti-tumor activity, systematic and organ protection activity (such as bone protection, cardiovascular protection, neuroprotection), anti-inflammatory activity, antioxidant activity, immune regulation as well as action mechanism of CSA and its derivatives. The most studied activities are antipathogenic micro-organisms activities. Additionally, the structure–activity relationships of CSA and its derivatives as well as the total synthesis of CSA are explored, highlighting the potential for developing new pharmaceutical agents. This review aims to provide a foundation for future clinical applications of CSA and its derivatives. Full article

The commercial use of Si₃N₄ ceramics in the biomedical field dates back to the early 1980s and, initially, did not show promising results, which is why their biocompatibility was not then investigated further until about 10 years later. Over the years, a change in trend has been observed; more and more studies have shown that this material could possess high biocompatibility and antibacterial properties. However, the relevant literature struggles to find mechanisms that can incontrovertibly explain the reasons behind the biological activity of Si₃N₄. The proposed mechanisms are often pure hypotheses or are not substantiated by comprehensive analyses. This review begins by studying the early references to the biological activity of Si₃N₄ and then reviews the literature regarding the bioactivity of this ceramic over time. An examination of the early insights into surface chemistry and biocompatibility lays the foundation for a detailed examination of the chemical reactions that Si₃N₄ undergoes in biological environments. Next, the analysis focuses on the mechanisms of bioactivity and antipathogenicity that the material exhibits both alone and in combination with modern bioglass. However, it is highlighted that despite the general consensus on the biocompatibility and bioactivity of Si₃N₄ ceramics, sometimes the proposed biological mechanisms behind its behavior are discordant or unsupported by the direct evaluation of specific biochemical activities. This review highlights both the reliable information in the literature and the gaps in research that need to be filled in order to fully understand the reasons behind the biological properties of this material. Full article

Bacterial quorum sensing (QS) is a critical communication process that regulates gene expression in response to population density, influencing activities such as biofilm formation, virulence, and antibiotic resistance. This study investigates the inhibitory effects of five phytochemicals—apigenin, carnosol, chlorogenic acid, quercetin, and rosmarinic acid—on the S-ribosylhomocysteinase (LuxS) enzyme, a key player in AI-2 signaling across both Gram-positive and Gram-negative bacteria. Using molecular docking studies, we identified that these phytochemicals interact with the LuxS enzyme, with apigenin, carnosol, chlorogenic acid, and rosmarinic acid binding within the substrate-binding pocket and exhibiting binding scores below −7.0 kcal/mol. Subsequent in vitro assays demonstrated that these compounds inhibited AI-2 signaling and biofilm formation in Escherichia coli MG1655 in a concentration-dependent manner. Notably, carnosol and chlorogenic acid showed the most potent effects, with IC₅₀ values of approximately 60 μM. These findings suggest that these phytochemicals may serve as potential QS inhibitors, providing a foundation for developing new anti-pathogenic agents to combat bacterial infections without promoting antibiotic resistance. Further studies are warranted to explore the therapeutic applications of these compounds in both clinical and agricultural settings. Full article

The rise of antibiotic-resistant bacteria poses a significant challenge to the treatment of bacterial infections, necessitating the development of novel antibiotics or strategies to preserve the efficacy of existing ones. This study investigates the role of oxidative stress modulation in the pathogenicity of multidrug-resistant (MDR) bacterial strains, aiming to identify potential avenues for new drug design. Specifically, the anti-biofilm effects of crude extracts and fractions from seven halophyte species native to Jeju Island, South Korea, were evaluated against Acinetobacter baumannii ATCC 17978. Notably, the 85% aqueous methanol fraction of Peucedanum japonicum Thunb. (Pj) and the n-hexane fraction of Lysimachia mauritiana Lam. (Lm) demonstrated significant anti-biofilm activity. Further assessments revealed that these fractions also exhibited notable antioxidant and anti-inflammatory properties, with the Pj fraction showing a lifespan extension effect in the Caenorhabditis elegans model. These findings suggest that Pj and Lm hold promise as potential candidates for the development of new therapeutic agents targeting MDR bacteria. Full article