Search Results (68)

The genus Bacillus is widely recognized for its metabolic versatility, enabling it to colonize extreme environments, including sites contaminated with metals. In this study, we report the genome of B. velezensis strain HM1, isolated from sulfur-rich mine tailings from silver mining activities in southwestern Mexico. Isolation was performed by heat treatment followed by selective cultivation in a medium enriched with mine tailings extract (metals and sulfates), resulting in a single dominant morphotype corresponding to strain HM1. Whole-genome sequencing was carried out using the Illumina NovaSeq platform (2 × 250 bp). The assembled genome of strain HM1 has a size of 4,044,128 bp, distributed across 20 contigs, with an N50 of 700,388 bp and an L50 of 3, and an average coverage of 66.8×. The GC content was 46.31%, with an estimated completeness of 99.81% and contamination of 0.01%. Genome analyses indicate that the assembly corresponds to a single chromosome, with no evidence of plasmid replicons. Genome annotation identified 3950 coding sequences (CDSs), 83 tRNAs, 11 rRNAs, 26 ncRNAs, and 4 sORFs. Phylogenomic analysis, together with genomic similarity metrics (ANI > 98.6%, AAI > 98.8%, dDDH > 87%), confirms its classification as Bacillus velezensis. Functionally, the genome encodes multiple genes involved in resistance to metals and metalloids (including ABC transporters, efflux pumps, and biotransformation enzymes), as well as a complete pathway for sulfate assimilation. Collectively, these genomic features reveal a broad repertoire of adaptive strategies employed by strain HM1 to thrive in metal-contaminated environments. Full article

Wastewater treatment plants represent a primary source of environmental dissemination of multidrug-resistant (MDR) bacteria, underscoring the urgent need for in-depth investigation of these organisms. While the resistome of MDR bacteria has been extensively studied, there remains a critical gap in understanding the role of plasmid-borne genes encoding adaptive metabolic functions. We isolated two MDR strains from municipal wastewater, Klebsiella sp. KOS9 and Pseudomonas veronii Yu15, both exhibiting resistance to antibiotics, including ampicillin, cefazolin, kanamycin, streptomycin, erythromycin, chloramphenicol, tetracycline, and ciprofloxacin. The plasmids of these strains harbored genes encoding aliphatic amidases, as well as antibiotic resistance genes (ARGs) and enzymes involved in glycogen and dTDP-L-rhamnose biosynthesis, which may contribute to virulence. In Klebsiella sp. KOS9 a single acetamidase operon, was found on the megaplasmid, along with copper and silver resistance genes. P. veronii Yu15 harbored an operon containing the acetamidase and formamidase genes on the chromosome, as well as a phylogenetically distant acetamidase operon on the conjugative megaplasmid. Both strains exhibit acetamidase activity and P. veronii Yu15 was able to utilize acetamide and formamide as sole nitrogen sources. The occurrence of ARGs and adaptive accessory genes on plasmids likely enhances the competitiveness and environmental flexibility of these MDR bacteria. Full article

This study investigated the adaptive mechanisms of silver pomfret in response to chronic low-temperature stress, focusing on the tissue-specific expression patterns of the key lipid metabolism gene scd1 and its central role in regulating hepatic apoptosis. A gradual cooling experiment (from 18 °C to 6 °C) was conducted to analyze the spatiotemporal expression profiles of ten lipid metabolism-related genes across six tissues. The results revealed that the most pronounced changes were observed in the heart, liver, and gills. The liver and heart rapidly activated genes involved in lipid breakdown and utilization from 16 to 12 °C for immediate energy supply, while gill tissue upregulated the pi3k/p450/srebp/scd1 pathway at 10 °C to remodel membrane lipids against sustained stress. Further in vitro hepatocyte experiments demonstrated that scd1 expression directly regulated cell survival and apoptosis under low temperatures. Knockdown of scd1 significantly promoted apoptosis, whereas its overexpression effectively suppressed it. Moreover, scd1 expression was intricately modulated by its upstream regulators srebp (positive regulation) and pparγ (showing potential negative feedback at specific temperatures). This study systematically elucidates the pivotal role of scd1-mediated lipid metabolic reprogramming in the cold adaptation of silver pomfret, providing a crucial theoretical foundation for deciphering the molecular mechanisms of cold tolerance and for breeding cold-resistant strains. Full article

Assessing genetic diversity in various native poultry breeds, including bantam/dwarf ones, is instrumental for their conservation as genetic resources, identifying their specific genetic features, and exploring the history of their genetic divergence. Rare chicken breeds are usually carriers of peculiar phenotypic traits, including adaptations to local conditions, disease resistance, and unique performance features. Here, we report for the first time SNP-based genetic characterization of the Russian Korolyok, translated as “kinglet,” relative to five other dwarf/small breeds: Cochin Bantam, Hamburg Bantam Silver Spangled, Polish White-crested Black, Red White-tailed Dwarf and Silkie White. We estimated phenotypes, heterozygosity, inbreeding, effective population size, and runs of homozygosity (ROHs). Some breeds had higher genetic diversity and others showed elevated inbreeding rates in their genomes. With lower effective population sizes (both presently and in the past), rare breeds came from a limited number of ancestors or were under strong selection pressure over many generations. Within 22 ROHs, we identified 26 prioritized candidate genes (GRB10, RPRD1A, APOOL, EAF2, SEMA5, HACD2, GALANT1, DACH2, CHM, POF1B, HDX, SLC15A2, PDIA5, SEC22, NR2F2, ARRDC4, IGF1R, SYNM, TMEM263, etc.). Our data offer whole-genome insights into genetic variability, history, phylogeny, selective sweeps, and candidate genes of a distinct indigenous Russian chicken breed and other bantam/dwarf breeds. Full article

With the growing global population and the challenges posed by climate change on agriculture, improving seed germination quality has become an urgent task. Nanotechnology, particularly silver nanoparticles (AgNPs), offers a promising approach to this issue. However, their long-term environmental impact and health risks require further evaluation.This review first explores the physicochemical properties of AgNPs and their effects on plant growth and seed development. Next, the review discusses the mechanisms by which AgNPs enhance seed resistance to pathogens, regulate reactive oxygen species (ROS) balance, activate key metabolic enzymes, induce metabolite accumulation, and modulate plant hormone levels. Additionally, the review explores how AgNPs influence seed gene expression, proteomic networks, and the germination microenvironment. Given the lack of field data on long-term low-dose exposure and challenges in monitoring morphological transformation, the review also evaluates the potential risks of AgNPs in agriculture. These risks include their accumulation in the food chain, environmental transformation, and long-term effects.The review aims to summarize the mechanisms by which AgNPs impact seed germination and plant growth, providing a theoretical basis for their cautious use in agricultural and horticultural practices, while considering their environmental fate and health risks. Full article

Due to the indiscriminate use of antimicrobial drugs in the treatment of infectious diseases, human pathogenic bacteria have developed resistance to many commercially available antibiotics. Medicinal plants such as Convolvulus arvensis represent a renewable resource for the development of alternative therapeutic agents. This study aimed to evaluate the antibacterial activity of silver nanoparticles (AgNPs) biosynthesized from C. arvensis against two clinical antibiotic-resistant bacterial isolates. The pathogenic isolates were identified as Staphylococcus aureus MRSA and Escherichia coli ESBL using 16S rRNA gene sequencing. Silver nanoparticles were synthesized via a green synthesis approach, and their physicochemical properties were characterized using UV–Vis spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, zeta potential, and dynamic light scattering (DLS). The synthesized C. arvensis–AgNPs exhibited a surface plasmon resonance peak at 475 nm and predominantly spherical morphology with particle sizes ranging from 102.34 to 210.82 nm. FTIR analysis indicated the presence of O–H, C–O, C–N, C–H, and amide functional groups. The nanoparticles showed a zeta potential of −18.9 mV and an average hydrodynamic diameter of 63 nm. The antibacterial activity of the biosynthesized AgNPs was evaluated against methicillin-resistant S. aureus (MRSA and ATCC 29213) and E. coli (ESBL and ATCC 25922) using agar diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays. Inhibition zones ranged from 10 to 13 mm, with MIC and MBC values of 12.5–25 µg/mL and 25–50 µg/mL, respectively. In addition, the nanoparticles exhibited antioxidant activity (DPPH assay, IC₅₀ = 0.71 mg/mL) and anti-inflammatory effects as determined by protein denaturation inhibition. No cytotoxic effects were observed in the MCF-7 cell line at the MIC level. These findings suggest that C. arvensis–AgNPs have potential as natural antimicrobial, antioxidant, and anti-inflammatory agents. Full article

Parasitic infections, particularly those caused by Haemonchus contortus (H. contortus), severely impact livestock production, with growing resistance to commercial anthelmintics posing a major challenge. Green-synthesized metallic nanoparticles using Artemisia cina (A. cina), a plant with known anthelmintic and antioxidant properties, represent a promising sustainable alternative for parasite control. In this study, silver nanoparticles (AgNPs) were synthesized using an aqueous extract of A. cina to evaluate their anthelmintic activity against infective larvae (L3) of H. contortus and their effect on the expression of oxidative stress-related genes. The larval mortality bioassay was conducted in 96-well microtiter plates by incubating L3 larvae with increasing AgNP concentrations for 24 h. To investigate oxidative stress responses, larvae were exposed to sublethal concentrations of AgNPs, A. cina aqueous extract, AgNO₃, and H₂O₂. Expression levels of SOD, GPx, and CAT genes were then quantified by RT-qPCR at multiple post-exposure time intervals. The synthesis was optimized by varying parameters such as pH, temperature, and extract volume. The nanoparticles were characterized using UV-Vis spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS), and Electrophoretic Light Scattering (ELS). Overall, synthesis at pH 8 yielded small, spherical, stable, and abundant AgNPs. In vitro assays on L3 larvae showed a mortality rate of 91.33% at the highest AgNP concentration (500 μg/mL), with lethal concentration (LC50 and LC90) values of 4.128 ppm (μg/mL) and 17.993 μg/mL, respectively. Relative expression analyses revealed that AgNPs induced the overexpression of the SOD gene, highlighting its role in the oxidative stress response. In contrast, the expression levels of GPx and CAT genes were markedly downregulated. These results suggest that SOD could serve as a potential biomarker of oxidative stress induced by AgNPs in combination with A. cina metabolites, influencing the infective stages of H. contortus. Full article

The increasing prevalence of antibiotic resistance necessitates the development of novel antimicrobial agents and therapeutic strategies. This study reports the extracellular biosynthesis of silver selenide nanoparticles (Ag₂Se NPs) using Meyerozyma guilliermondii PG-1 and evaluates their antimicrobial and antibiofilm efficacy, both alone and in combination with gentamicin. The NPs were thoroughly characterized, confirming their nanoscale size, crystallinity, and biomolecule-mediated stability. Ag₂Se NPs exhibited broad-spectrum antibacterial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa, Escherichia coli) pathogens and showed strong synergy with gentamicin, particularly against P. aeruginosa and E. coli, as demonstrated through checkerboard and time–kill assays. The NPs also significantly inhibited biofilm formation and disrupted pre-formed biofilms. Mechanistic studies revealed that the antibacterial effects involved membrane disruption, ATP leakage, and elevated oxidative stress, while gene expression analysis in S. aureus indicated triggered stress responses related to biofilm formation. These findings suggest that biosynthesized Ag₂Se NPs represent a promising synergistic agent for enhancing antibiotic efficacy and combating biofilm-related infections. Full article

Mutant yeast strains with altered sensitivity to heavy metals are crucial for revealing the mechanisms of metal absorption and detoxification, as well as for bioremediation of these pollutants. Here, we show that a knockout of the PHO87 gene encoding the low-affinity phosphate transporter of the cytoplasmic membrane of S. cerevisiae increased resistance to manganese, silver, and vanadate ions. However, a knockout of PHO90 (PHO87 paralog) did not affect the sensitivity to silver and vanadate ions but increased sensitivity to manganese ions. The Δpho87 cells accumulated 10 times less manganese compared to the wild-type cells, while the Δpho90 cells accumulated two times more manganese compared to the wild-type cells, when grown in YPD with 2 mM MnSO₄. The polyphosphate content of the Δpho84, Δpho87, and Δpho90 cells cultivated at high phosphate concentration did not differ from that of the wild-type strain. In the presence of 2 mM MnSO₄, Δpho87 cells contained several times less polyphosphates, and Δpho90 cells contained more short-chain polyphosphates than the cells of the wild-type strain. We hypothesize that phosphate carriers participate in the regulation of heavy metal uptake, and the respective knockouts are useful in bioremediation and bioassay of these pollutants. Full article

Antimicrobial resistance (AMR) is a growing global health emergency that threatens the effectiveness of modern medicine, exacerbating healthcare costs, morbidity, and mortality, particularly in low- and middle-income countries (LMICs). Traditional approaches to antimicrobial development and stewardship have proven inadequate in curbing the rapid emergence and spread of resistant pathogens. This review explores cutting-edge biotechnological innovations as sustainable, precision-based solutions to combat AMR and promote global health equity. A comprehensive narrative review was conducted using literature published between 2018 and 2023 from PubMed, ScienceDirect, and Web of Science. Peer-reviewed studies focusing on novel antimicrobial strategies were thematically analyzed, with attention to efficacy, feasibility, and translational readiness. Key innovations identified include nanotechnology-enhanced antimicrobial delivery, bacteriophage therapy, CRISPR-Cas gene editing, immunotherapy, and personalized medicine. These strategies demonstrated substantial in vitro and in vivo efficacy, such as >90% MRSA biofilm reduction via silver nanoparticles and 95% carbapenem susceptibility restoration in E. coli using CRISPR-Cas9. When integrated with machine learning and rapid diagnostics, these approaches enable precision-targeted therapies and data-informed stewardship, offering scalable solutions adaptable to diverse healthcare systems. Antimicrobial resistance demands urgent, equitable innovation. Integrating biotechnologies like CRISPR, phage therapy, and nanomedicine with data-driven tools offers promising solutions. To ensure real-world impact, we recommend establishing regionally tailored translational research platforms and public–private partnerships as the most effective strategy to scale innovations and strengthen AMR response in low-resource settings. Full article

Methicillin-resistant Staphylococcus aureus (MRSA), characterized by high-level β-lactam resistance and increasing multi-drug resistance, poses a severe and growing global threat to human health and public safety. This review examines MRSA’s complex resistance mechanisms, including mecA/mecC-mediated expression of low-affinity PBP2a, regulatory roles of auxiliary genes like fem and vanA, enzymatic inactivation by β-lactamases and modifying enzymes, efflux pump activity, and biofilm formation. We also systematically review novel therapeutic strategies, such as combination therapies, phage-derived biofilm disruptors, membrane-targeting silver nanoparticles, cell-penetrating antimicrobial peptides, colonization-competitive probiotics, and antibiotic-synergizing phytochemicals. These advances provide critical insights for developing effective countermeasures against MRSA, while highlighting the urgent need for global collaboration, antibiotic stewardship, and innovative drug development to combat antimicrobial resistance. Full article

Multidrug-resistant (MDR) biofilm infections characterized by densely packed microbial communities encased in protective extracellular matrices pose a formidable challenge to conventional antimicrobial therapies and are a major contributor to chronic, recurrent and device-associated infections. These biofilms significantly reduce antibiotic penetration, facilitate the survival of dormant persister cells and promote horizontal gene transfer, all of which contribute to the emergence and persistence of MDR pathogens. Metal nanoparticles (MNPs) have emerged as promising alternatives due to their potent antibiofilm properties. However, conventional synthesis methods are associated with high costs, complexity, inefficiency and negative environmental impacts. To overcome these limitations there has been a global push toward the development of sustainable and eco-friendly synthesis approaches. Recent advancements have demonstrated the successful use of various plant extracts, microbial cultures, and biomolecules for the green synthesis of MNPs, which offers biocompatibility, scalability, and environmental safety. This review provides a comprehensive overview of recent trends and the latest progress in the green synthesis of MNPs including silver (Ag), gold (Au), platinum (Pt), and selenium (Se), and also explores the mechanistic pathways and characterization techniques. Furthermore, it highlights the antibiofilm applications of these MNPs emphasizing their roles in disrupting biofilms and restoring the efficacy of existing antimicrobial strategies. Full article

Methicillin-resistant Staphylococcus aureus (MRSA) continues to represent a significant clinical challenge, characterized by consistently elevated rates of morbidity and mortality. Care regimen success is still difficult and necessitates assessing new antibiotics as well as supplemental services, including source control and searching for alternative approaches to combating it. Hence, we propose to synthesize silver nanoparticles (Ag-NPs) by employing a cell-free filter (CFF) of Streptomyces sp. to augment antibiotic activity and combat biofilm-forming MRSA. Seven bacterial isolates from clinical samples were identified, antibiotics were profiled with Vitek-2, and the phenotypic detecting of biofilm with Congo red medium and microplate assay was carried out. The PCR technique was used for detecting genes (icaA and icaD) coded in biofilm forming. The characterization of Ag-NPs was performed using several analytical methods, such as UV spectroscopy, dynamic light scattering (DLS), zeta potential measurement, transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The antibacterial properties of Ag-NPs and oxacillin–Ag-NPs were assessed against standard strains and clinical isolates by employing the agar well diffusion technique and the microdilution assay. The biogenic synthesis Ag-NPs resulted in uniformly spherical particles, with an average size of 20 nm. These Ag-NPs demonstrated significant activity against biofilm-forming MRSA, with minimum inhibitory concentrations (MICs) ranging from 12 to 15 μg/mL. Additionally, Ag-NPs completely impede biofilm formation by MRSA at sublethal doses of 0.75 MICs. The expression levels of the icaA and icaD genes were reduced by 1.9- to 2.2- and 2.4- to 2.8-fold, respectively. A significant synergistic effect was noted when Ag-NPs were used in combination with oxacillin, leading to reduced MICs of 1.87 μg/mL for oxacillin and 4.0 μg/mL for Ag-NPs against MRSA. The FICi of 0.375 further validated the synergistic relationship between oxacillin and Ag-NPs at the concentrations of 1.87 and 4 μg/mL. Findings from the time-kill test demonstrated the highest reduction in log₁₀ (CFU)/mL of the initial MRSA inoculum after 12-hour exposure. The cytotoxicity analysis of Ag-NPs revealed no significant cytotoxic effects on the human skin cell line HFB-4 at low concentrations, with IC₅₀ values of 61.40 µg/mL for HFB-4 and 34.2 µg/mL for HepG-2. Comparable with oxacillin–Ag-NPs, Ag-NPs showed no cytotoxic effects on HFB-4 at different concentrations and exhibited an IC₅₀ value of 31.2 against HepG-2-cells. In conclusion, the biosynthesis of Ag-NPs has demonstrated effective antibacterial activity against MRSA and has completely hindered biofilm formation, suggesting a valuable alternative for clinical applications. Full article

Background/Objectives: This study aims to characterize antibiotic resistance (AR) and virulence markers in Salmonella spp. isolated from Romanian outpatients’ stool samples. Methods: In 2019, community-acquired Salmonella strains were collected and identified using MALDI-TOF mass spectrometry, antibiotic susceptibility profiles have been determined with the MicroScan system, and soluble virulence factors were evaluated using specific culture media, while biofilm formation was quantified in 96-well plates. Molecular analysis targeted resistance genes for β-lactams (e.g., bla_TEM and bla_SHV); tetracyclines (e.g., tet(A)); sulphonamides; and quinolones, as well as virulence genes (e.g., invA, spvC, pldA, and held). Whole-genome sequencing (WGS) was performed on 19 selected isolates. A silver nanoparticles (AgNPsol) alternative to conventional antibiotics was tested for effectiveness against multidrug-resistant (MDR) isolates. Results: From the total of 309 Salmonella isolates (65.05% from children under 4 years of age) belonging to four subtypes and four serovars, 27.86% showed resistance to at least one antibiotic, most frequently to tetracycline, ampicillin, and piperacillin. The strains frequently expressed haemolysin (67%), aesculinase (65%), and gelatinase (62%). Resistance to trimethoprim-sulfamethoxazole was encoded by the sul1 gene in 44.83% of the strains and to tetracyclines by the tet(A) gene (59.52%). The ESBL genes bla_TEM, bla_SHV, and bla_CTX-M were detected by PCR in 16.18%, 2.91%, and 0.65% of the strains, respectively. Additionally, 98.63% of the strains carried the invA marker, with notable positive associations between bla_SHV, qnrB, and sul1 with spvC. Conclusions: The present findings revealed significant patterns in Salmonella isolates, subtypes, serovars, AR, and virulence, emphasising the need for continuous surveillance of Salmonella infections. Additionally, the potential of AgNPs as an alternative treatment option was demonstrated, particularly for paediatric S. enterica infections. Full article

Background: The worldwide misuse of antibiotics is one of the main factors in microbial resistance that is a serious threat worldwide. Alternative strategies are needed to overcome this issue. Objectives: In this study, a novel strategy was adopted to suppress the growth of resistant pathogens through immobilization of silver nanoparticles (AgNPs) in gum of Moringa oleifera. Methods: The AgNPs were prepared from the leaves of Moringa oleifera and subsequently characterized through UV-spectrophotometry, FTIR, SEM, and XRD. The differential ratios of characterized AgNPs were immobilized with gum of M. oleifera and investigated for antimicrobial potential against highly resistant pathogens. Results: The immobilized AgNPs displayed promising activities against highly resistant B. subtilis (23.6 mm; 50 µL:200 µL), E. coli (19.3 mm; 75 µL:200 µL), K. pneumoniae (22 mm; 200 µL:200 µL), P. mirabilis (16.3 mm; 100 µL:200 µL), P. aeruginosa (22 mm; 175 µL:200 µL), and S. typhi (19.3; 25 µL:200 µL) than either AgNPs alone or gum. The immobilized AgNPs released positive sliver ions that easily attached to negatively charged bacterial cells. After attachment and permeation to bacterial cells, the immobilized NPs alter the cell membrane permeability, protein/enzymes denaturation, oxidative stress (ROS), damage DNA, and change the gene expression level. It has been mechanistically considered that the immobilized AgNPs can kill bacteria by damaging their cell membranes, dephosphorylating tyrosine residues during their signal transduction pathways, inducing cell apoptosis, rupturing organelles, and inhibiting cell division, which finally leads to cell death. Conclusions: This study proposes a potential alternative drug for curing various infections. Full article