Search Results (2,260)

Plant growth-promoting rhizobacteria (PGPR) employ various mechanisms to enhance plant development and growth as well as to mitigate environmental stress, including heavy metal contamination. Cadmium is a particularly severe stressor, toxic to both plants and soil microbiota. Mesembryanthemum crystallinum L. (the common ice plant), a fast-growing semi-halophyte, was previously investigated for phytoremediation potential towards saline environments and toxic metals, especially cadmium and chromium. The study was aimed at assessing whether bacteria isolated from the rhizosphere of M. crystallinum treated with Cd reveal growth-promoting traits and if the plant tolerance to Cd results from a synergistic action of the Cd/salt-resistant strains. The isolates demonstrated PGP characteristics, including nitrogen fixation, phosphate solubilization, and production of ammonia, indolyl-3-acetic acid (IAA), and siderophores. A microbial consortium consisting of these strains was developed and applied to pots with M. crystallinum. After a 14-day experiment, plant growth and Cd-accumulation potential were evaluated upon treatment with 1 mM or 10 mM Cd, either in the presence or absence of NaCl. Plant inoculation with the consortium stimulated Cd accumulation both by roots and shoots at 10 mM Cd under saline conditions. The results suggest that bioaugmentation of M. crystallinum with the bacterial community can be used as an effective, sustainable phytoremediation method for cadmium-contaminated soils. Full article

Bacterial antibiotic resistance (AR) has become a critical global health threat. AR is mainly driven by adaptive resistance mutations and the horizontal gene transfer of resistance genes, both of which are enhanced by genome recombination. We previously discovered that genome recombination-mediated tRNA upregulation is important for AR, especially in the early stages. RecA is a crucial bacterial factor mediating genome recombination and the DNA damage response. Therefore, RecA inhibitors should be effective in reducing AR. In this study, we found that BRITE-338733 (BR), a RecA inhibitor, can prevent ciprofloxacin (CIP) resistance in subculturing Escherichia coli strain BW25113 in the early stages (up to the 7th generation). In the presence of BR, the tRNA was decreased, so the bacteria cannot evolve resistance via the tRNA upregulation-mediated AR mechanism. The RecA expression level was also not increased when treated with BR. Transcriptome sequencing revealed that BR could inhibit oxidative phosphorylation, the electron transport chain process, and translation, thereby reducing the bacterial energy state and protein synthesis. Also, the effective concentrations of BR do not harm human cell viability, indicating its clinical safety. These findings demonstrate that BR effectively delays the emergence of spontaneous AR by targeting RecA-mediated pathways. Our findings shed light on a new strategy to counteract clinical AR: applying BR with the antibiotics together at the beginning. Full article

Antimicrobial resistance (AMR) presents a global health challenge, necessitating comprehensive surveillance and intervention strategies. Wastewater-based epidemiology (WBE) is a promising tool that can be utilized for AMR monitoring by offering population-level insights into microbial dynamics and resistance gene dissemination in communities. This review (n = 29 papers) examines the current landscape of utilizing WBE for AMR surveillance with a focus on methodologies, findings, and gaps in understanding. Reported methods from the reviewed literature included culture-based, PCR-based, whole genome sequencing, mass spectrometry, bioinformatics/metagenomics, and antimicrobial susceptibility testing to identify and measure antibiotic-resistant bacteria and antimicrobial resistance genes (ARGs) in wastewater, as well as liquid chromatography-tandem mass spectrometry to measure antibiotic residues. Results indicate Escherichia coli, Enterococcus spp., and Pseudomonas spp. are the most prevalent antibiotic-resistant bacterial species with hospital effluent demonstrating higher abundances of clinically relevant resistance genes including bla, bcr, qnrS, mcr, sul1, erm, and tet genes compared to measurements from local treatment plants. The most reported antibiotics in influent wastewater across studies analyzed include azithromycin, ciprofloxacin, clindamycin, and clarithromycin. The influence of seasonal variation on the ARG profiles of communities differed amongst studies indicating additional factors hold significance when examining the conference of AMR within communities. Despite these findings, knowledge gaps remain, including longitudinal studies in multiple and diverse geographical regions and understanding co-resistance mechanisms in relation to the complexities of population contributors to AMR. This review underscores the urgent need for collaborative and interdisciplinary efforts to safeguard public health and preserve antimicrobial efficacy. Further investigation on the use of WBE to understand these unique population-level drivers of AMR is advised in a proposed framework to inform best practice approaches moving forward. Full article

Background: Previous studies have demonstrated the beneficial effects of Ligilactobacillus salivarius A3iob on honeybee (Apis mellifera) colonies’ health and honey production. The present work aimed to assess the genomic characteristics of the A3iob strain to understand its ability to improve bees’ health. Methods: The comparative genomic analysis was performed with the A3iob genome and the genomes of probiotic L. salivarius strains of human, porcine, and chicken origin, as well as bacteria isolated from the bees’ gut. The analysis included the examination of metabolic genes and functional genes related to adhesion, the production of bioactive compounds, the modulation of the host’s immune system, and antimicrobial substances. Genes associated with antimicrobial resistance and virulence were also analyzed. Results: In silico studies revealed that L. salivarius A3iob possesses genes for glycosyltransferases (GTs) from the families GT2 and GT4, like Bombella apis and Bombella intestinalis, and glycosylhydrolases (GH) from the families GH1, GH2, GH13, GH36, GH65, and GH177, similar to Apilactobacillus kunkeei, Enterococcus durans, and bifidobacteria isolated from the bee intestine. The A3iob strain also has a unique genetic profile with a high number of secretion system genes and adhesion genes, including the ones coding for the SecA2/Y2 system, the mucus-binding proteins MucBP1, MucBP2, and MucBP3, and a pilus cluster (pilA, SpaA, SpaB, and sorteaseA) that has only been described in five strains of the L. salivarius species and in the intestinal bee-derived strain E. durans EDD2, which could be involved in the successful colonization of the A3iob strain in the bee gastrointestinal tract. Additionally, L. salivarius A3iob showed the presence of exopolysaccharide biosynthesis clusters described in the probiotic L. salivarius UCC118. Genes related to oxidative stress response (thioredoxin and NrdH-redoxin systems) and the bacteriocin genes abp118A and abp118B were found in the A3iob genome. L. salivarius A3iob does not harbor virulence or antibiotic resistance genes. Conclusions: The genomic characterization of L. salivarius A3iob performed in this work provides some clues about the genetic mechanisms underlying its probiotic properties, paving the way for future research aimed at improving bees’ health and productivity in the face of environmental challenges. Full article

Biofilms are structured communities of microorganisms embedded in a self-produced extracellular polymeric substance (EPS) matrix; they form by sticking to a surface, growing in number, spreading out, developing fully, and breaking apart. Biofilm represents a risk of infections linked to healthcare environments. It can be one of the leading causes of nosocomial infections, which can colonize the surface of medical equipment, including respirators, urinary and central venous catheters, prosthetic heart valves, and orthopaedic devices. Biofilm formation in urinary catheters is the most common and plays a role in multidrug resistance, especially in patients with catheter-associated urinary tract infections. The supply of antibiotics for the treatment of biofilm bacteria is still inadequate due to continued antibiotic resistance, and the search for a cure for biofilm bacteria in urinary catheters is still under development. Most research currently focuses on preventing biofilm bacteria from adhering to the urinary catheter. This review discusses biofilm bacteria that form with catheter-associated urinary tract infection mechanisms and pathogenesis. In addition, the factors affecting the biofilm development by catheter-associated urinary tract infections were explained. Full article

The phyllosphere, the aerial part of plants, serves as a crucial habitat for diverse microorganisms. Phyllosphere bacteria can activate protective mechanisms that help plants resist disease. This study focuses on isolating and characterizing phyllosphere bacteria from cucurbits to evaluate their potential in controlling Colletotrichum orbiculare, a pathogen causing anthracnose in cucumbers. Among the 76 bacterial isolates collected, 11 exhibited strong antagonistic effects against C. orbiculare in vitro. Morphological and 16S rRNA analyses identified these isolates as different Bacillus species, including B. vallismortis, B. velezensis, B. amyloliquefaciens, and B. subtilis. These bacteria demonstrated essential plant-growth-promoting and biocontrol traits, such as motility, biofilm formation, phosphate solubilization, nitrogen fixation, and the production of indole acetic acid. Most of the bacterial strains also produced biocontrol compounds such as ammonia, acetoin, siderophores, hydrogen cyanide, chitinase, protease, lipase, and cellulase. The application of these bacteria significantly enhanced cucumber growth in both non-manured and organically manured soils, showing improvements in root and shoot length, chlorophyll content, and biomass accumulation. Additionally, bacterial treatments effectively reduced anthracnose severity, with isolates GL-10 and L-1 showing the highest disease suppression in both soil types. Colonization studies showed that phyllobacteria preferentially colonized healthy leaves over roots and diseased tissues, and they were more effective in manure-amended soils. These results suggest that Bacillus phyllobacteria have strong potential as sustainable bio-stimulants and biocontrol agents, offering an effective approach for enhancing cucumber growth and disease control under both fertilized and unfertilized soil conditions. Full article

In this study, the preparation and detailed characterization of a chitosan (CHT) impregnation system modified with cellulose nanofibrils (CNFs) and enriched with bioactive compounds—caffeine (CAF) and gallic acid (GA)—applied to the surface of unbleached paperboard were described. Their mechanical properties (tensile strength, elongation at break, and bursting strength), structural features, and surface barrier parameters (water absorption) were evaluated. The antibacterial activity of the formulations comprising 1% chitosan (1% CHT), 1% chitosan with 1% caffeine (1% CHT/1% CAF), and 1% chitosan with 1% gallic acid (1% CHT/1% GA)—applied to enhance the functionality of the coated paperboard—was additionally assessed. The incorporation of cellulose nanofibrils into the coating matrix markedly improved the mechanical performance of the paperboard, particularly in terms of puncture resistance and elongation at break, while all modified coatings retained high burst strength. Impregnations containing gallic acid or caffeine showed similar mechanical characteristics but improved flexibility without compromising structural integrity. Chitosan solutions containing gallic acid and solutions containing caffeine exhibited activity against the tested Gram-positive (S. aureus, L. monocytogenes) and Gram-negative (E. coli, P. aeruginosa) bacterial strains. Antibacterial analysis showed moderate activity against Gram-positive strains and strong inhibition of Gram-negative bacteria, with the 1% CHT/1% GA impregnation giving the largest zone of growth inhibition around the sample—19 mm in the agar diffusion test—indicating the strongest suppression of E. coli. It was found that incorporation of nanocellulose into the chitosan matrix significantly reduces water uptake by treated paperboard surface, which is critical in the context of food packaging. The best result—Cobb₆₀ value of 32.85 g/m²—was achieved for the 1% CHT/1% CNF formulation, corresponding to an 87% reduction in water absorption compared to the uncoated control. The results obtained in this study indicate a promising potential for the use of these impregnation systems in sustainable packaging applications. Full article

Disease outbreaks pose a significant challenge in aquaculture, leading to substantial economic losses for producers. Tenacibaculosis, a significant ulcerative bacterial disease caused by Tenacibaculum maritimum, affects a wide range of marine fish species globally. Current disease management relies on antibiotics and chemicals, leading to environmental issues, impaired fish and consumer health, and increased antimicrobial-resistant bacteria. This narrative review critically explores welfare-oriented alternatives, specifically examining the potential of temperature modulation and functional diets. Although thermal strategies show promise for warm-water species through behavioural fever mechanisms, their effectiveness remains limited by species-specific thermal tolerances and lack of commercial validation. Nutritional interventions using marine algae, probiotics, and immunostimulants demonstrate broader applicability but suffer from inconsistent methodologies, limited commercial validation, and significant knowledge gaps. We propose that integration of these approaches could theoretically represent a paradigm shift from pathogen-focused to host-centred disease management, pending empirical validation. However, this integration concept requires rigorous validation, as significant knowledge gaps persists regarding optimal implementation protocols, welfare monitoring frameworks, and economic viability assessments. From our perspective, transitioning to welfare-oriented aquaculture demands rigorous evaluation and validation, commercial-scale trials, economic cost–benefit analysis, and the establishment of regulatory frameworks before these theoretical alternatives can be responsibly implemented. Full article

Arid and semi-arid regions show distinctive bacterial groups important for the sustainability of ecosystems and soil health. This study aims to investigate how environmental factors across five Qatari soils influence the taxonomic composition of bacterial communities and their predicted functional roles using 16S rRNA amplicon sequencing and soil chemical analysis. Soil samples from five different locations in Qatar (three coastal and two inland) identified 26 bacterial phyla, which were dominated by Actinomycetota (35–43%), Pseudomonadota (12–16%), and Acidobacteriota (4–13%). Species-level analysis discovered taxa such as Rubrobacter tropicus, Longimicrobium terrae, Gaiella occulta, Kallotenue papyrolyticum, and Sphingomonas jaspsi, suggesting the presence of possible novel microbial families. The functional predictions showed development in pathways related to amino acid metabolism, carbohydrate metabolism, and stress tolerance. In addition, heavy-metal-related taxa, which are known to harbor genes for metal resistance mechanisms including efflux pumps, metal chelation, and oxidative stress tolerance. The presence of Streptomyces, Pseudomonas, and Bacillus highlights their roles in stress tolerance, biodegradation, and metabolite production. These findings improve the understanding of microbial roles in dry soils, especially in nutrient cycling and ecosystem resilience. They highlight the importance of local bacteria for sustaining desert soil functions. Further research is needed to validate these relationships, using metabolomic approaches while monitoring microbial-community-changing aspects under fluctuating environmental conditions. Full article

Radioactive wastewater generated from nuclear energy, medical, and industrial sectors poses persistent ecological and health risks, necessitating the development of safe and sustainable treatment strategies. Compared with conventional physicochemical approaches, bioremediation using radiation-resistant bacteria (RRB) provides distinct advantages, including lower energy requirements, reduced secondary pollution, and superior ecological compatibility. This review synthesizes current knowledge on RRB’s biological characteristics, molecular resistance mechanisms, and applications in radioactive wastewater treatment. Moreover, potential applications in non-radioactive wastewater treatment—such as selective removal of heavy metals, degradation of refractory organics, and mitigation of antibiotic resistance—are discussed. Evidence from existing studies indicates that RRB share fundamental adaptive traits, including extraordinary radiotolerance, unique morphological modifications, and cross-tolerance to multiple stressors, which are underpinned by specialized DNA repair systems, potent antioxidant defenses, and radiation-responsive regulatory networks. These mechanisms collectively confer the ability to withstand and mitigate radiation-induced damage. Future research should responsibly prioritize the genetic engineering of RRB and its integration with complementary technologies, such as microbial fuel cells, to achieve synergistic pollutant removal and energy recovery. This synthesis provides a theoretical basis and technical reference for advancing RRB-enabled bioremediation toward sustainable wastewater management. Full article

The emergence of bacterial resistance has spurred an urgent need to develop effective alternatives to traditional antibiotics. Phenylethyl alcohol from plants exhibits potential antimicrobial properties, but its efficacy is limited due to its compromised dispersion in water and structural stability in ambient conditions. Herein, for the first time, a polymerization-induced self-assembly strategy was employed to obtain different morphological nanogels with phenylethyl alcohol moieties as hydrophobic cores through in situ reversible addition–fragmentation chain-transfer (RAFT) polymerization. The well-defined copolymers of PTEG_x-co-PPMA_y with controllable molecular weights and narrow polydispersity were confirmed by a combination of techniques. The generated phenylethyl alcohol-based nanogels demonstrated potent antibacterial activity, particularly PTEG₃₀-co-PPMA₇₀ with a one-dimensional linear architecture, which achieved a minimum inhibitory concentration of 62 μg mL⁻¹ against E. coli. SEM revealed membrane disruption as the bactericidal mechanism, highlighting enhanced efficacy against Gram-negative bacteria due to structural differences in cell envelopes. This study establishes a robust platform for designing phenylethyl alcohol-based nanogels with controllable structures toward achieving potent antimicrobial performance, offering a promising strategy for combating bacterial resistance while addressing the dilemma of conventional antibiotic drug systems. Full article

Active packaging supports sustainable development by extending food shelf life and reducing spoilage, contributing to global food security. In this study, cellulose dialdehyde was synthesized and blended with polyvinyl alcohol in varying ratios to produce composite films. The incorporation of dialdehyde cellulose into films tended to increase puncture strength and Young’s modulus, decrease elongation, reduce water solubility, and enhance resistance to water vapor transmission because of crosslinking. Carbon quantum dots were subsequently incorporated into composite films to enhance their antibacterial property. This represents a novel combination of a natural bio-based crosslinker and fluorescent nanomaterials in a single packaging system. Carbon quantum dots were synthesized by an electrochemical method and incorporated as functional agents. The addition of carbon quantum dots influenced the mechanical properties of the films due to interactions between polymers and carbon quantum dots. This interaction also slightly reduced the antibacterial effectiveness of the films, consisting of dialdehyde cellulose and PVA in ratios of 3:1 and 4:0. Nevertheless, the composite films maintained sufficient antimicrobial activity against common foodborne bacteria, including Staphylococcus aureus, Escherichia coli, and Salmonella Typhimurium. Overall, the findings demonstrate that multifunctional material made from dialdehyde cellulose, polyvinyl alcohol, and carbon quantum dots are a promising alternative to conventional plastic packaging. Full article

Mushrooms, renowned for their nutritional value and bioactive compounds, offer potential health benefits, including antioxidants and anti-aging properties. Aging, characterized by cellular and tissue decline, is often associated with autophagy dysfunction, a crucial cellular cleaning process. This study aimed to investigate the neuroprotective, hepatoprotective, and antimicrobial properties of extracts from four medicinal and edible mushrooms: Ganoderma lucidum, Hericium erinaceus, Pleurotus ostreatus, and Agaricus bisporus. The protein, total phenol, and flavonoid content of mushroom extracts were determined. Aging was induced with 120 mg/kg D-galactose and treated with 500 mg/kg mushroom extracts. The study evaluated liver enzyme levels, histopathological changes in liver and brain tissues, gene expression correlated to neurodegeneration (SEPT5-SV2B-ATXN2-PARK2), telomere length, and immunomodulatory and pro-inflammatory (IL-2-IL-4-IL-6) gene expression pathways. Additionally, the antimicrobial potential of mushroom extracts was assessed against several bacteria (Lysinibacillus odyssey, Lysinibacillus fusiformis, Klebsiella oxytoca, and Escherichia coli) using agar well diffusion and lowest minimum inhibitory concentration (MIC) methods. By exploring these diverse aspects, this study aimed to provide a foundation for a better understanding of the potential of mushrooms as natural neuroprotective, hepatoprotective, and antimicrobial agents and their potential applications in human health. Results indicated that all mushroom extracts effectively mitigated oxidative stress. Agaricus bisporus exhibited the highest protein and flavonoid content, and Pleurotus ostreatus displayed the highest phenolic content. Notably, Hericium erinaceus and Ganoderma lucidum extracts demonstrated significant neuroprotective and hepatoprotective properties against D-galactose-induced aging, as evidenced by histopathological examination. All extracts exhibited a significant decrease (p < 0.001) in liver function (serum levels of aspartate aminotransferase (GOT) and alanine aminotransferase (GPT)) and showed immunomodulatory and anti-inflammatory effects, characterized by upregulated IL-2 and IL-4 gene expression and downregulated IL-6 gene expression. Hericium erinaceus demonstrated the most pronounced upregulation (p < 0.001) of SEPT5, SV2B, and telomere length gene expression, suggesting potential anti-aging effects. Furthermore, all mushroom extracts displayed antimicrobial activity against the tested bacterial strains, except Hericium erinaceus, which exhibited antibacterial activity solely against E. coli. Agaricus bisporus exhibited the largest inhibition zones (22 ± 0.06 mm) against Lysinibacillus odyssey, while Hericium erinaceus displayed the largest inhibition zone against E. coli. The MIC value was observed with Agaricus bisporus extract against Lysinibacillus odyssey (1.95 ± 0.16 mg/mL). Lysinibacillus fusiformis exhibited the highest resistance to the tested mushroom extracts. These findings suggest that these edible and medicinal mushrooms possess a wide range of health-promoting properties, including neuroprotective, hepatoprotective, and antimicrobial activities. Further research is needed to fully understand the underlying mechanisms and optimize applications. However, our results provide a strong foundation for exploring these mushrooms as potential natural agents that promote overall health and combat age-related decline. Full article

Bacteria and phages have coexisted for billions of years engaging in continuous evolutionary arms races that drive reciprocal adaptations and resistance mechanisms. Among the diverse antiviral strategies developed by bacteria, modification or masking phage receptors as well as their physical removal via extracellular vesicles are the first line of defense. These vesicles play a pivotal role in bacterial survival by mitigating the effects of various environmental threats, including predation by bacteriophages. The secretion of extracellular vesicles represents a highly conserved evolutionary trait observed across all domains of life. Bacterial extracellular vesicles (BEVs) are generated by a wide variety of Gram (+), Gram (−), and atypical bacteria, occurring under both natural and stress conditions, including phage infection. This review addresses the multifaceted role of BEVs in modulating bacteria–phage interactions, considering the interplay from both bacterial and phage perspectives. We focus on the dual function of BEVs as both defensive agents that inhibit phage infection and as potential facilitators that may inadvertently enhance bacterial susceptibility to phages. Furthermore, we discuss how bacteriophages can influence BEV production, affecting both the quantity and molecular composition of vesicles. Finally, we provide an overview of the ecological relevance and efficacy of BEV–phage interplay across diverse environments and microbial ecosystems. Full article

Two-component systems (TCSs) are ubiquitous in bacteria and are central to their ability to sense and respond to diverse environmental and intracellular cues. Classically composed of a sensor histidine kinase and a cognate response regulator, TCSs control processes ranging from metabolism and development to virulence and antibiotic resistance. In addition to their biological roles, TCSs are garnering attention in synthetic biology and antimicrobial drug development. While canonical architectures have been extensively studied, increasing evidence highlights the remarkable diversity in their organization and regulation. Despite substantial progress, key questions remain regarding the prevalence and physiological relevance of non-canonical TCSs, the mechanisms ensuring signal fidelity, and the potential for engineering these systems. This review explores non-typical TCSs, focusing on their varied transcriptional regulation, alternative response regulator activities, varied control by phosphorylation, and negative control mechanisms. We discuss how bacteria manage signaling specificity among numerous TCSs through cross-talk, hierarchical interactions, and phosphorelay systems and how these features shape adaptive responses. By synthesizing current understanding and highlighting still existing knowledge gaps, this review offers a novel perspective on TCS diversity, indicating directions for future research and potential translational applications in biotechnology and medicine. Full article