Search Results (4,301)

Microplastics (MPs) have become widespread environmental contaminants, with increasing evidence of their harmful impacts on human health. MPs generally enter the human body via ingestion, inhalation, or dermal exposure, with the gastrointestinal tract acting as a crucial entrance route. This work utilized the SHIME system to evaluate the effects of polystyrene (PS) MPs on gut microbiota and short-chain fatty acid (SCFA) metabolism in distinct colonic areas. The results demonstrated regional and individual-specific variations in microbial diversity, significant shifts in Firmicutes/Bacteroidetes (F/B) ratio, and declines in beneficial bacteria, such as Bifidobacteriaceae. Moreover, SHIME supernatants were then tested with a co-cultured cell model (Caco-2/HT29-MTX-E12). Results indicated a deteriorative effect on the intestinal model, characterized by enhanced oxidative stress and mitochondrial malfunction. No significant effect on intestinal barrier integrity or mucus secretion was detected. These findings highlight the potential systemic toxicity of PS-MPs on human gut microbiota-mediated mechanisms, emphasizing the necessity for immediate mitigation efforts. Full article

Celtis africana, a rare plant native to southwestern Saudi Arabia, was explored for the first time as a source for the green synthesis of silver nanoparticles (AgNPs). Catechol-bearing phenolic amides in the aqueous leaf extract acted as both reducing and capping agents, enabling eco-friendly AgNP fabrication. The synthesized AgNPs were characterized using SEM, TEM, XRD, UV-Vis, and FTIR, revealing predominantly spherical nanoparticles with an average size of 9.28 ± 0.11 nm, a face-centered cubic crystalline structure, and a pronounced surface plasmon resonance at 424 nm. HPLC analysis confirmed the presence of caffeoyltryamine in the extract, while UV-Vis and FTIR indicated its attachment to the AgNP surface. The AgNPs exhibited broad-spectrum antimicrobial activity against Gram-positive bacteria (S. aureus, MRSA and E. faecalis) and Gram-negative bacteria (E. coli, K. pneumoniae, S. typhimurium, and P. aeruginosa), as well as pathogenic fungi such as C. albicans, C. glabrata, C. parapsilosis, and C. krusei with performance comparable to or exceeding that of AgNPs from Artemisia vulgaris, Moringa oleifera, and Nigella sativa. The MIC and MBC values for S. aureus, MRSA, E. coli, and S. typhimurium were consistently 6.25 µg/mL and 25 µg/mL, respectively, reflecting strong inhibitory and bactericidal effects at low concentrations. MTT assays demonstrated selective cytotoxicity, showing higher viability in normal human skin fibroblasts (HSF) than in MCF-7 breast cancer cells. The AgNPs also displayed strong antioxidant activity (IC₅₀ = 5.41 µg/mL, DPPH assay) and efficient catalytic reduction of 4-nitrophenol (4-NP) and methylene blue (MB), with rate constants of 0.0165 s⁻¹ and 0.0047 s⁻¹, respectively, exceeding most reported values. These findings identify Celtis africana as a promising source for eco-friendly AgNPs with strong antimicrobial, antioxidant, and catalytic properties for broad biological and environmental applications. Full article

Gyms are indoor environments in which many people perform physical exercise and could potentially increase the risks of bacterial contamination and dissemination. Staphylococcus aureus (S. aureus) is one of the most prevalent bacteria in community-acquired infections; thus, the rapid detection and continuous monitoring of S. aureus are crucial for evaluating the hygienic status of gym environments. This work describes the fabrication of a nanochain-based biosensor for S. aureus detection using carboxyl-modified polystyrene (PS) nanoparticles functionalized with a specific antibody. When target bacteria bind to the nanochains, they yield distinct color changes which support the directly visualizable analysis of optical images, recorded using optical microscopy or even a smart mobile phone. In addition to high portability, this biosensor is also capable of the quantification and continuous monitoring of the bacterial load in a gym environment over a broad linear range (10⁰ CFU/mL~10⁵ CFU/mL), with a detection limit of 1 CFU/mL. In summary, this study validated the applicability of the biosensors for the rapid detection and real-time monitoring of gym environmental pathogens. Full article

The poultry industry plays a major role in the emergence and spread of foodborne zoonotic diseases, particularly those associated with antibiotic-resistant bacteria. These diseases pose substantial global public health challenges, and the increasing development of antimicrobial resistance further intensifies these concerns. In response, scientific efforts have expanded to develop and implement innovative technologies capable of mitigating the rising prevalence of multidrug-resistant (MDR) microorganisms. Therapeutic bacteriophage supplementation has regained significant attention because it can selectively lyse specific bacteria, is cost-effective to produce, offers environmentally favorable characteristics, and provides several advantages over conventional antibiotics. Experimental studies have demonstrated that phage therapy is both safe and effective for controlling poultry-associated enteric pathogens. Phages can be applied at various stages of the poultry production chain, from rearing to processing and distribution, using multiple delivery strategies. Despite certain limitations, the targeted and well-regulated application of phage cocktails offers considerable potential as an alternative to antibiotics for managing MDR infections. The success of bacteriophage therapy depends on several factors, including the timing of administration, dosage, delivery method, and its integration with other therapeutic approaches. Therefore, developing a comprehensive understanding of bacteriophage utilization in poultry production is both timely and necessary. This review examines the applications, constraints, and future opportunities of phage therapy within the commercial poultry industry, with particular emphasis on the mechanisms through which bacteriophages control bacterial infections. Full article

Micro- and nanoplastics (MNPs) are increasingly recognized as emerging intestinal toxicants. This scoping review maps and integrates evidence from 56 studies (47 primary and 11 review articles, 2000–mid-2025) on how nanoplastics, particularly ≤100 nm polystyrene, disrupt gut homeostasis. The evidence consistently supports a three-stage mechanistic cascade: 1. Oxidative-stress initiation—Nanoplastics generate reactive oxygen species (ROS) and suppress antioxidant defenses, producing redox imbalance in intestinal tissue and commensal bacteria. 2. Barrier dysfunction—Resulting oxidative injury reduces tight-junction proteins, depletes mucus-secreting goblet cells, and activates inflammatory signaling (NF-κB, TLR4). 3. Microbiome reconfiguration—The altered intestinal microenvironment favors Gram-negative expansion and depletion of Gram-positive commensals, observed as decreases in the Firmicutes/Bacteroidetes (F/B) and Gram+/Gram− ratios. High-dose nanoplastic exposures reproducibly induced these effects in mice and zebrafish, whereas environmentally realistic, low-dose PET fragments produced minimal dysbiosis. Functionally important taxa—short-chain-fatty-acid producers (Faecalibacterium, Roseburia) and mucin degraders (Akkermansia muciniphila)—were consistently reduced, linking microbial shifts to epithelial injury and inflammatory tone. Together, these findings define an oxidative–barrier–microbiome axis as the dominant pathway of nanoplastic-induced intestinal disruption. Future work should emphasize environmentally relevant exposures, multi-omics functional endpoints, and mechanistic models that integrate oxidative stress, epithelial pathology, and microbiome ecology to guide realistic human-health risk assessment. Full article

Two-component systems (TCSs) are widespread in bacteria and archaea, with only limited presence in eukaryotes. These signaling mechanisms detect environmental changes and adjust gene expression to survive and adapt. In this review, TCSs were examined within the Pasteurellaceae family, focusing on how closely related organisms employ similar systems to regulate infections and stress responses. Comparative analysis revealed that homologous TCSs can differ markedly in the signals they detect and in the genes or virulence factors they control, underscoring the functional diversity that has evolved even within this family. Inconsistencies in nomenclature across studies are also identified, which complicate data integration and cross-species comparisons. Given these challenges, the need for unified naming conventions and broader, system-level analyses is highlighted. It is further proposed that emerging computational tools—including molecular modeling, molecular dynamics, and neural network-based analyses—offer powerful strategies to predict signaling interactions, identify conserved regulatory models, and clarify how these systems contribute to bacterial adaptation and pathogenicity. Full article

In order to explore the co-evolutionary relationship between the functions of microbial communities and the chemical composition of groundwater in a hyporheic zone affected by groundwater exploitation along riverbank, we have taken the Huangjia water source area on the Liao River main stream in Shenyang as an example. DNA was extracted from microorganisms in the hyporheic zone affected by groundwater exploitation along the riverbank, and we conducted high-throughput sequencing to select the dominant bacterial strains from the indigenous bacteria. They are classified as the Proteobacteria phylum, the Actinobacteria phylum, the Firmicutes phylum, the Bacteroidetes phylum, the Chloroflexi phylum, and the Acidobacteria phylum. The dominant bacteria have a good correlation with Fe, Mn, and environmental factors (such as DO—dissolved oxygen, Eh—oxidation-reduction potential, etc.) in the hyporheic zone. The functions and activities of the superior bacterial strains exhibit a feature of co-evolution with the water’s chemical environment, which has certain response characteristics to redox zoning. Studying the co-evolution relationship between the microbial community structure and function in the hyporheic zone and the chemical composition of the groundwater can provide a microbiological theoretical basis for the redox zonation. It also offers reference for understanding the process of Fe and Mn migration and transformation in the hyporheic zone under the hydrodynamic conditions of groundwater exploitation along the riverbank. Full article

Natural whey starter (NWS) cultures are microbial consortia characterized by high microbial diversity in terms of genus and species, as well as strains, accounting for the variety of different characteristics and quality of the artisanal fermented food. By means of a combined approach, using plate counts, bacterial isolation, molecular identification, and genotyping, we analyzed 41 colonies isolated from NWS of cow milk used in the production of caciocavallo, a typical pasta filata Italian cheese. Results revealed that 27 of them were lactic acid bacteria (LAB), including Lactococcus lactis as the dominant species, followed by Streptococcus thermophilus, Enterococcus faecium, Limosilactobacillus fermentum, Lactobacillus helveticus, and Lacticaseibacillus rhamnosus. The remaining isolates were taxonomically identified as non-LAB, probably due to environmental contamination. These results were mostly confirmed by metagenomic analysis, with the exception of only three species. Finally, small-scale fermentation experiments were performed in both standard media and skimmed milk to further characterize the newly isolated LAB strains. Overall, our results show that, except for four of the Lactococcus isolates and one Streptococcus, which show multi-drug resistance, the isolated strains under study exhibit levels of acidifying, metabolic properties, and safety parameters, suggesting their potential as starter cultures in cheese production. Full article

Sorghum (Sorghum bicolor (L.) Moench) is increasingly recognized as a sustainable crop due to its adaptability to challenging environmental conditions and its nutritional potential. The present study aimed to characterize the nutritional composition and native microbial species associated with three sorghum hybrids cultivated in Bulgaria. Crude protein was 9.37–10.42%, total carbohydrate content was between 87.4 and 89.6%, and crude fat content was in the range of 3.84–4.9%. Linoleic acid was the predominant fatty acid in all hybrids, accounting for 44.9% to 48.0% of total lipids. Quinic acid emerged as the dominant organic acid in all hybrids, with the highest concentration of 729.37 mg/100 g. The microbiological assessment focused on lactic acid bacteria (LAB) and yeasts. Microbial isolates were subjected to molecular identification through 16S rRNA gene and ITS region sequencing. The predominant LAB species included Levilactobacillus brevis, Lactiplantibacillus plantarum, Lactiplantibacillus pentosus, Pediococcus acidilactici, and Pediococcus pentosaceus, while most of the yeast isolates belonged to Saccharomyces cerevisiae. Phylogenetic analysis indicated substantial intraspecies variation, particularly within LAB strains, suggesting the presence of unique genotypic traits. These findings contribute to a better understanding of sorghum’s nutritional value and endogenous microbiota and open opportunities for developing sorghum-based functional products. Full article

Although CsbD-like proteins have been studied extensively in bacteria, their functions in eukaryotes remain largely uncharacterized. Our study investigated the CsbD homolog MaCsbD in the entomopathogenic fungus Metarhizium acridum and uncovered its importance for coping with environmental stress. Loss of MaCsbD resulted in delayed conidial germination, reduced conidial yield, and heightened sensitivity to UV-B irradiation and heat shock. The mechanism analysis revealed that the absence of MaCsbD led to a decline in DNA repair capacity, a weakening of the antioxidant defense mechanism, and a reduction in the induction of heat shock proteins. The determination of the accumulation levels of protective metabolites, melanin, and trehalose in the conidia showed that their contents were significantly decreased. Phylogenetic analysis further revealed that CsbD-like domains are conserved across fungi, suggesting an evolutionary role in stress adaptation. Virulence against locusts was unchanged, indicating that MaCsbD primarily supports abiotic stress tolerance rather than pathogenicity. MaCsbD is therefore required for robust fungal stress responses and identifies a potential target for improving the field performance of fungal biocontrol strains. Full article

Background: Environmental surfaces are key reservoirs for pathogen transmission, with the survival of bacteria on fomites influenced by factors such as temperature, humidity, and microbial interactions. This study aimed to determine microbial surface contamination and to determine the antimicrobial resistance profile of bacteria isolated from the indoor surface where the presence of cockroaches was observed in households of the Greater Letaba Municipality (GLM), South Africa. Methods: Swab samples were collected from kitchen countertops and food storage areas with visible cockroach activity. Bacteria were isolated and identified using standard microbiological methods, and antimicrobial susceptibility testing (AST) was conducted with the Vitek^® Automated 2 system. Results: Of the 120 samples collected, 82 (68%) showed bacterial growth, resulting in 190 isolates. The majority of isolates (93%) were Gram-negative, comprising Klebsiella, Pseudomonas, Enterobacter, Escherichia, Serratia, Stenotrophomonas, Pantoea, Raoultella, and Salmonella species, with 98% demonstrating multidrug resistance (MDR) to multiple antibiotics. Resistance was particularly high against gentamicin (94%), fluoroquinolones (88%) and amikacin (77%). Among Gram-positive isolates, all belonged to the Enterococcus species, with 22% being resistant to one or two of the tested antimicrobial agents and 78% exhibiting MDR. Conclusions: The study revealed a high prevalence of antibiotic resistance in both Gram-positive and Gram-negative bacteria isolated from household surfaces. The spread of antibiotic-resistant pathogens via environmental surfaces presents a significant risk to human health, safety, and well-being. Full article

Moraxella osloensis is an infrequently reported component of the human skin microbiota, but it has recently been recognized as a potential source of intraoperative contamination. Its pathogenic role remains poorly defined, particularly in shoulder arthroplasty. This study describes the recovery and characterization of M. osloensis from intraoperative periprosthetic tissue samples collected immediately after reverse total shoulder arthroplasty in five patients. All isolates exhibited low colony counts (10–50 CFU/mL), were uniformly susceptible to the antimicrobial agents tested, and did not produce β-lactamases. Biofilm formation—an important virulence determinant in periprosthetic joint infections—was detected in two of the five isolates. Clinically, no patient developed postoperative infection within 12 months, and only one experienced a transient superficial wound-healing delay, which resolved with a short administration of oral antibiotics. These findings indicate that M. osloensis may be present in the operative field despite stringent skin preparation and aseptic protocols, likely reflecting endogenous colonization rather than environmental contamination. Although its clinical impact appears limited in this context, the bacteria’s biofilm-forming potential and underrecognized presence in the operating room underscore the importance of continued surveillance and careful interpretation when isolated from surgical specimens. Full article

Chile, the leading exporter of cherries (Prunus avium L.) in the southern hemisphere, faces sustained variations in precipitation patterns and high evaporative demand in its productive areas. The low availability of water during the period of highest environmental demand makes it essential to reduce or suspend irrigation applications. In this scenario, regulated deficit irrigation (RDI) after harvest is an efficient strategy for optimizing water use without compromising orchard yields. This study was conducted over three consecutive seasons in a traditional commercial orchard of ‘Santina’ cherry trees grafted onto Colt rootstock, evaluating the effect of two levels of RDI, moderate (MDI) and severe (SDI), on productive and ecophysiological parameters. Both treatments resulted in water savings of between 10% and 28%, without negatively affecting yield or fruit quality. The SDI treatment, despite reaching higher levels of cumulative water stress, improved intrinsic water use efficiency while maintaining stable photosynthetic efficiency. In addition, an increase in the abundance of fine roots and beneficial rhizosphere bacteria populations, such as Azospirillum and Bacillus, was observed, suggesting the activation of water resilience mechanisms mediated by plant–microbiota interaction, possibly associated with stress-induced ecological memory and microbial legacy effects. These results position after-harvest RDI as a sustainable tool for coping with climate variability and water scarcity in commercial cherry orchards. Full article

The growth of microalgae poses a significant threat to the preservation of stone heritage, particularly in ornamental fountains and water-related architecture. Traditional chemical cleaning methods, such as quaternary ammonium compounds and chlorine-based solutions, are often ineffective and can be harmful to both the environment and cultural properties. In response, biocleaning, which involves the use of live microorganisms and is part of biorestoration, is gaining prominence in cultural heritage conservation, offering a sustainable alternative to conventional methods. The use of microorganisms antagonistic to microalgae growth has been extensively studied in environmental biotechnology to eliminate harmful algae, though its application in heritage conservation remains limited. This review summarizes current knowledge on bacteria capable of inhibiting microalgae growth, discussing their mechanisms, effectiveness, and potential applications, alongside the environmental and economic benefits and challenges of these methods. By collating and critically assessing available information, this paper aims to serve as a comprehensive resource for conservators, restorers, and researchers interested in innovative and sustainable approaches to combat biodeterioration in stone heritage, thereby fostering the development of effective and environmentally sustainable treatments for such culturally significant properties. Full article

N-tetradecanoyl-L-homoserine lactone (C₁₄-HSL) is a long-chain signaling molecule belonging to acyl-homoserine lactones (AHLs), which is widely present in the quorum sensing (QS) system of Gram-negative bacteria. In this study, the effects of C₁₄-HSL on chalcopyrite bioleaching mediated by Acidithiobacillus ferrooxidans (A. ferrooxidans) were investigated. After cultivating A. ferrooxidans with different energy substrates and exploring the potential mechanisms of signal molecule production, chalcopyrite was selected as the energy substrate for further study. Molecular docking analysis revealed that the high binding affinity between AHL and the receptor protein AfeR in A. ferrooxidans was beneficial for the activation of transcription by the AfeR-AHL complex, promoting their biological impact. The variations in the physicochemical parameters of pH, redox potential, and copper ions revealed that after adding C₁₄-HSL, the leaching rate of chalcopyrite increased (1.15 times during the initial 12 days). Further analysis of the mechanism of extracellular polymers formation indicated that the presence of C₁₄-HSL could promote the formation of biofilms and the adhesion of bacteria, facilitating mineral leaching rate of A. ferrooxidans. This research provides a theoretical basis for regulating the biological leaching process of chalcopyrite and metal recovery using signaling molecules, which could also be used to control environmental damage caused by acid mine/rock drainage. Full article