Search Results (885)

Dental enamel discoloration, extrinsic staining, and periodontal biofilms remain persistent challenges in oral health. This study explores the in vitro, dual-functional potential of Magnolia figo flower extract (FMO), a sesquiterpene-rich botanical active phytochemical ingredient (API), for aesthetic and antimicrobial oral applications. FTIR identified characteristic terpenoid and long-chain fatty acid functional groups, including β-elemene, γ-elemene, and caryophyllene oxide. Whitening efficacy on coffee-stained bovine enamel was quantified using CIELAB colorimetry. The 0.5% FMO treatment achieved ΔE* = 8.49, which was within the clinical perceptibility threshold and the optimal biocompatibility balance. SEM confirmed no demineralization on the enamel surface after immersion in 3.0% FMO for 12 h. Antimicrobial assays demonstrated inhibition of Porphyromonas gingivalis, with MIC and MBC values of 0.25% and 0.5%, respectively. Biofilm formation was reduced by over 50% at a 0.148% concentration. Cytocompatibility assays using HGF-1 cells with various concentrations of FMO showed reduced cell viability at higher concentrations. When exposed for 5 min (simulating daily oral care) or 2 h, 0.5% FMO exhibited greater biocompatibility with L929 cells compared to toothpaste and peroxide-based agents. These findings suggest that FMO may serve as a natural candidate for dual-function oral care; however, further in vivo and clinical investigations are needed to validate its potential use within oral care treatments. Full article

Toxicological effects of microplastics (MPs) have been confirmed in a variety of microorganisms in aquatic environments, and they are closely correlated with the physicochemical properties of the MPs. In a natural environment, different aging treatments always induce different alterations in the physicochemical properties of MPs, thus influencing their environmental behaviors and biotoxicity. In this work, physicochemical properties and toxicity towards Escherichia coli (E. coli) were investigated in polystyrene (PS) MPs (3 and 10 μm) before and after aging by UV irradiation and biofilm formation, respectively. The results show that UV irradiation and biofilm formation led to different alterations in the surface morphologies and functional groups of PS. The UV-aged 3 μm PS had the strongest inhibitory effect on E. coli growth, and the bio-aged 10 μm PS had the strongest beneficial effect on E. coli growth. Also, the ATPase activity, production of intercellular ROS, and MDA content of the E. coli were affected differently. UV aging enhanced the toxicity of PS towards E. coli, while bio-aging had an opposite weakening effect. Overall, our research verified the remarkable differences in the physicochemical properties and biotoxicity of PS induced by UV aging and bio-aging. Full article

Bacterial infections cause serious problems associated with wound treatment and serious complications, leading to serious threats to the global public. Bacterial resistance was mainly attributed to the formation of biofilms and their protective properties. Hydrogels suitable for irregular surfaces with effective antibacterial activity have attracted extensive attention as potential materials. In this study, a succinoglycan-riclin-zinc-phthalocyanine-based composite (RL-Zc) hydrogel was synthesized through an amine reaction within an hour. The hydrogel was characterized via FT-IR, SEM, and rheology analysis, exhibiting an elastic solid gel state stably. The hydrogel showed large inhibition circles on E. coli as well as S. aureus under near-infrared irradiation (NIR). RL-Zc hydrogel exhibited positively charged surfaces and possessed a superior penetrability toward bacterial biofilm. Furthermore, RL-Zc hydrogel generated abundant single oxygen and mild heat rapidly, resulting in disrupted bacterial biofilm as well as amplified antibacterial effectiveness. A metabolomics analysis confirmed that RL-Zc hydrogel induced a metabolic disorder in bacteria, which resulted from phospholipid metabolism and oxidative stress metabolism related to biofilm disruption. Hence, this study provided a potential phototherapy for biofilm-induced bacterial resistance. Full article

Stone cleaning for cultural heritage monuments is a critical conservation intervention that must effectively eliminate harmful surface contaminants while preserving the material’s physical, chemical, and historical integrity. This study investigated the removal of tenacious black biofilms formed by Nocardia species previously isolated from deteriorated limestone from the Bastet tomb in Tell Basta, Zagazig City, Egypt, using a Q-switched 1064 nm Nd:YAG laser. Experimental limestone specimens were systematically inoculated with Nocardia sp. under controlled laboratory conditions to simulate biodeterioration processes. Comprehensive testing revealed that a laser fluence of 0.03 J/cm² with a 5 ns pulse duration, applied under wet conditions with 500 pulses, achieved the complete elimination of the biological black film without damaging the underlying stone substrate. The cleaning efficacy was evaluated through an integrated analytical framework combining stereomicroscopy, scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX), X-ray diffraction (XRD), and laser-induced plasma spectroscopy (LIPS). These analyses demonstrated a remarkable transformation from a compromised mineralogical composition dominated by gypsum (62%) and anhydrite (13%) to a restored state of 98% calcite, confirming the laser treatment’s effectiveness in reversing biodeterioration processes. SEM micrographs revealed the complete elimination of mycelial networks that had penetrated to depths between 984 μm and 1.66 mm, while LIPS analysis confirmed the restoration of elemental signatures to near-control levels. The successful application of LIPS for real-time monitoring during cleaning provides a valuable tool for preventing overcleaning, addressing a significant concern in laser conservation interventions. This research establishes evidence-based protocols for the non-invasive removal of Nocardia-induced black biofilms from limestone artifacts, offering conservation professionals a precise, effective, and environmentally sustainable alternative to traditional chemical treatments for preserving irreplaceable cultural heritage. Full article

Pollution from synthetic polymers, particularly low-density polyethylene (LDPE), poses a significant environmental challenge due to its chemical stability and resistance to degradation. This study investigates an eco-biotechnological approach involving bacterial strains isolated from insect guts—Bacillus cereus LDPE-DB2 (from Achroia grisella) and Pseudomonas aeruginosa LDPE-DB26 (from Coptotermes formosanus)—which demonstrate the ability to degrade LDPE, potentially through the action of lignin-modifying enzymes. These strains exhibited notable biofilm formation, enzymatic activity, and mechanical destabilization of LDPE. LDPE-DB2 exhibited higher LDPE degradation efficiency than LDPE-DB26, achieving a greater weight loss of 19.8% compared with 11.6% after 45 days. LDPE-DB2 also formed denser biofilms (maximum protein content: 68.3 ± 2.3 µg/cm²) compared with LDPE-DB26 (55.2 ± 3.1 µg/cm²), indicating stronger surface adhesion. Additionally, LDPE-DB2 reduced LDPE tensile strength (TS) by 58.3% (from 15.3 MPa to 6.4 ± 0.4 MPa), whereas LDPE-DB26 induced a 43.1% reduction (to 8.7 ± 0.23 MPa). Molecular weight analysis revealed that LDPE-DB2 caused a 14.8% decrease in weight-averaged molecular weight (Mw) and a 59.1% reduction in number-averaged molecular weight (Mn), compared with 5.8% and 32.7%, respectively, for LDPE-DB26. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and gel permeation chromatography (GPC) analyses revealed substantial polymer chain scission and crystallinity disruption. Gas chromatography–mass spectrometry (GC-MS) identified environmentally benign degradation products, including alkanes, alcohols, and carboxylic acids. This study demonstrates a sustainable route to polyethylene biotransformation using insect symbionts and provides insights for scalable, green plastic waste management strategies in line with circular economy goals. Full article

Escherichia coli biofilms are implicated in the development of persistent infections and increased antibiotic resistance, posing a significant challenge in clinical settings. These biofilms enhance bacterial survival by forming protective extracellular matrices, rendering conventional treatments less effective. Serrapeptase (SPT), a proteolytic enzyme, has emerged as a potential anti-biofilm agent due to its ability to degrade biofilm components and disrupt bacterial adhesion. In this study, we report the inhibitory effect of SPT against E. coli biofilm and its effect on key virulence factors. In vitro assays, including crystal violet staining, optical and fluorescence microscopy, and viability measurements, revealed the dose-dependent inhibition of biofilm formation (IC₅₀ = 14.2 ng/mL), reduced biofilm (−92%, 500 ng/mL) and planktonic viability (−45%, 500 ng/mL), and a marked loss of amyloid curli fibers. SPT treatment also lowered the levels of key virulence factors: cellular and secreted lipopolysaccharides (−76%, 8 ng/mL; −94%, 32 ng/mL), flagellin (−63%, 8 ng/mL), and peptidoglycan (−29%, 125 ng/mL). Mechanistically, SPT induced a phosphate-dysregulating response: secreted alkaline phosphatase activity rose (+70%, 125 ng/mL) while cellular DING/PstS proteins declined (−84%, 64 ng/mL), correlating strongly with biofilm inhibition. In silico docking further suggests direct interactions between SPT and the curli subunits CsgA and CsgB, potentially blocking fiber polymerization. Together, these findings position SPT as a powerful non-antibiotic biofilm disruptor against E. coli, offering a promising strategy to undermine bacterial persistence and resistance by targeting both structural matrix components and metabolic regulatory pathways. Full article

Accumulation of copper (Cu) in soils devoted to intensive agriculture due to anthropogenic additions is becoming a significant threat to plant productivity. Biological inoculants may play an important role in alleviating toxic effects of heavy metals on plants. The plant-growth-promoting rhizobacteria (PGPR) Bacillus subtilis subsp. spizizenii has demonstrated the ability to reduce harmful impacts of heavy metals on crops. This study aimed to evaluate the suitability of seed inoculation with biofilm produced by this bacterium to mitigate the severity of Cu toxicity on tomato. In the laboratory, first, B. subtilis was cultivated under increased Cu concentrations. Then, germination of inoculated and non-inoculated tomato seeds was tested for Cu concentrations of 0, 50, 100, 150, and 200 ppm. Next, a greenhouse experiment was conducted for four months to assess the effects of both inoculation and excess 150 ppm Cu in the substrate. The studied treatments included control, no inoculation and Cu surplus, inoculation and no Cu surplus, and inoculation plus Cu surplus. In the laboratory, first, the bacterium’s ability to grow in a liquid medium containing Cu was confirmed. Thereafter, we verified that the germination of non-inoculated seeds was negatively affected by Cu, with higher concentrations leading to a more detrimental effect. However, seed inoculation with biofilm mitigated the adverse impact of Cu on germination. Under greenhouse conditions, excess Cu significantly reduced root dry weight, tomato number, and tomato yield compared with the control, whereas shoot dry weight, plant height, leaf area, and soluble solid concentration (Brix index) did not experience significant changes (p < 0.05). However, seed inoculation mitigated the toxic effects of excess Cu, significantly enhancing all the aforementioned plant parameters, except plant height. Seed inoculation also significantly reduced the Cu contents in the fruits of tomato plants growing in the metal contaminated substrate. The biofilm of the B. subtilis strain used demonstrated its effectiveness as a bioinoculant, attenuating the detrimental effects induced by a substrate with excess Cu. Full article

Background: Oral antiseptic formulations are widely used as adjuncts in oral hygiene to reduce pathogenic microorganisms and prevent oral diseases. While these agents are effective in controlling biofilm, their broader effects may disrupt the oral microbiota’s balance, potentially contributing to systemic health implications. The complex relationship between antiseptic use, microbial composition, and systemic outcomes remains insufficiently mapped. Objective: This scoping review aimed to explore and map the current evidence regarding the impact of antiseptic formulations on oral microbiota composition and to examine their potential associations with systemic diseases. Methods: A comprehensive literature search was performed using PubMed, Scopus, and Web of Science up to June 2025. Studies were included if they investigated antiseptic formulations commonly used in oral healthcare—such as chlorhexidine, essential oils, and cetylpyridinium chloride—and reported effects on oral microbiota and/or systemic health. Eligible study types included human clinical trials, observational studies, in vitro, and animal studies. Two reviewers independently screened and selected studies, with disagreements resolved by consensus. Data extraction focused on study design, antiseptic agents, microbial outcomes, and systemic implications. A total of 12 studies were included and charted. Results: The included studies demonstrated that oral antiseptics effectively reduce pathogenic microorganisms and improve clinical outcomes in oral diseases such as gingivitis and periodontitis. However, several studies also reported alterations in commensal microbial communities, suggesting a potential for dysbiosis. Some studies indicated possible links between antiseptic-induced microbial changes and systemic conditions, including cardiovascular and respiratory diseases. Conclusions: The evidence highlights a dual effect of antiseptic formulations: while beneficial in controlling oral pathogens, they may disrupt microbial homeostasis with possible systemic consequences. Further research is needed to evaluate long-term effects and develop targeted, microbiota-preserving oral hygiene strategies. Full article

Background/Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) remains a critical public health concern due to its multidrug resistance and capacity to form persistent infections, particularly in the context of implanted medical devices. Alternative therapeutic strategies that target bacterial virulence instead of viability are increasingly explored. This study aimed to evaluate the antimicrobial and antivirulence activity of an extract derived from Lacticaseibacillus rhamnosus CRL 2244 against two MRSA strains—USA300 and M86—and to elucidate its effects on bacterial physiology and gene expression under host-mimicking conditions. Methods: Antimicrobial activity was assessed using agar diffusion, MIC, and time-kill assays. Scanning electron microscopy of cells exposed to the extract confirmed decreased cellular density and morphological changes. Phenotypic assays evaluated biofilm formation, staphyloxanthin production, and adhesion to fibronectin. RT-qPCR analyzed transcriptional responses. Viability was assessed in the presence of human serum and type I collagen. Results: The CRL 2244 extract demonstrated bactericidal activity with up to 6-log₁₀ CFU/mL reduction at 1× MIC. In USA300, the extract reduced the expression of hla, lukAB, fnbA, and icaA, correlating with decreased staphyloxanthin levels. In M86, a significant reduction in biofilm formation and repression of lukAB, nucA, and fnbA were observed. Adhesion to fibronectin was impaired in both strains. The extract showed no cytotoxicity in human serum but reduced viability in collagen-enriched conditions. Conclusions: The Lcb. rhamnosus CRL 2244 extract modulates MRSA virulence in a strain-specific manner, targeting key regulatory and structural genes without inducing cytotoxic effects. Full article

Foodborne illness caused by bacterial pathogens is a global health concern and results in millions of infections annually. Therefore, food products typically undergo several processing stages, including sanitation steps, before being distributed in an attempt to remove pathogens. However, many sanitation methods have compounding effects on the color, texture, flavor, and nutritional quality of the product or do not effectively reduce the pathogens that food can be exposed to. Some bacterial pathogens particularly possess traits and tactics that make them even more difficult to mitigate such as biofilm formation. Non-thermal plasma sanitation techniques, including plasma-treated water (PTW), have proven to be promising methods that significantly reduce pathogenic bacteria that food is exposed to. Published work reveals that PTW can effectively mitigate both gram-positive and gram-negative bacterial biofilms. This study presents a novel analysis of the differences in antimicrobial effects of PTW treatment between biofilm-forming gram-positive bacteria, commonly associated with foodborne illness, that are sporulating (Bacillus cereus) and non-sporulating (Listeria monocytogenes). After treatment with PTW, the results suggest the following hypotheses: (1) that the non-sporulating species experiences less membrane damage but a greater reduction in metabolic activity, leading to a possible viable but non-culturable (VBNC) state, and (2) that the sporulating species undergoes spore formation, which may subsequently convert into vegetative cells over time. PTW treatment on gram-positive bacterial biofilms that persist in food processing environments proves to be effective in reducing the proliferating abilities of the bacteria. However, the variance in PTW’s effects on metabolic activity and cell vitality between sporulating and non-sporulating species suggest that other survival tactics might be induced. This analysis further informs the application of PTW in food processing as an effective sanitation method. Full article

Heavy metal pollution represents a pervasive environmental challenge that significantly exacerbates the ever-increasing crisis of antimicrobial resistance and the capacity of microorganisms to endure and proliferate despite antibiotic interventions. This review examines the intricate relationship between heavy metals and AMR, with an emphasis on the underlying molecular mechanisms and ecological ramifications. Common environmental metals, including arsenic, mercury, cadmium, and lead, exert substantial selective pressures on microbial communities. These induce oxidative stress and DNA damage, potentially leading to mutations that enhance antibiotic resistance. Key microbial responses include the overexpression of efflux pumps that expel both metals and antibiotics, production of detoxifying enzymes, and formation of protective biofilms, all of which contribute to the emergence of multidrug-resistant strains. In the soil environment, particularly the rhizosphere, heavy metals disrupt plant–microbe interactions by inhibiting beneficial organisms, such as rhizobacteria, mycorrhizal fungi, and actinomycetes, thereby impairing nutrient cycling and plant health. Nonetheless, certain microbial consortia can tolerate and detoxify heavy metals through sequestration and biotransformation, rendering them valuable for bioremediation. Advances in biotechnology, including gene editing and the development of engineered metal-resistant microbes, offer promising solutions for mitigating the spread of metal-driven AMR and restoring ecological balance. By understanding the interplay between metal pollution and microbial resistance, we can more effectively devise strategies for environmental protection and public health. Full article

Salmonella is one of the main causes of food-borne illness worldwide. In most cases, Salmonella contamination can be traced back to food processing plants and/or to cross-contamination during food preparation. To avoid food-borne diseases, food processing plants use sanitizers and biocidal to reduce bacterial contaminants below acceptable levels. Despite these preventive actions, Salmonella can survive and consequently affect human health. This study investigates the adaptive capacity of the main Salmonella enterica serotypes isolated from the poultry production line, focusing on their replication, antimicrobial resistance, and biofilm formation under stressors such as acidic conditions, oxidative environment, and high osmolarity. Using growth curve analysis, crystal violet staining, and microscopy, we assessed replication, biofilm formation, and antimicrobial resistance under acidic, oxidative, and osmotic stress conditions. Disinfectant tolerance was evaluated by determining the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of sodium hypochlorite. The antibiotic resistance was assessed using the Kirby–Bauer method. The results indicate that, in general, acidic and osmotic stress reduce the growth of Salmonella. However, no significant differences were observed specifically for serotypes Infantis, Heidelberg, and Corvallis. The S. Infantis isolates were the strongest biofilm producers and showed the highest prevalence of multidrug resistance (71%). Interestingly, S. Infantis forming biofilms required up to 8-fold higher concentrations of sodium hypochlorite for eradication. Furthermore, osmotic and oxidative stress significantly induced biofilm production in industrial S. Infantis isolates compared to a reference strain. Understanding how Salmonella responds to industrial stressors is vital for designing strategies to control the proliferation of these highly adapted, multi-resistant pathogens. Full article

Soil degradation resulting from intensive agricultural practices, the excessive use of agrochemicals, and climate-induced stresses has significantly impaired soil fertility, disrupted microbial diversity, and reduced crop productivity. Plant growth-promoting bacteria (PGPB) represent a sustainable biological approach to restoring degraded soils by modulating plant physiology and soil function through diverse molecular mechanisms. PGPB synthesizes indole-3-acetic acid (IAA) to stimulate root development and nutrient uptake and produce ACC deaminase, which lowers ethylene accumulation under stress, mitigating growth inhibition. They also enhance nutrient availability by releasing phosphate-solubilizing enzymes and siderophores that improve iron acquisition. In parallel, PGPB activates jasmonate and salicylate pathways, priming a systemic resistance to biotic and abiotic stress. Through quorum sensing, biofilm formation, and biosynthetic gene clusters encoding antibiotics, lipopeptides, and VOCs, PGPB strengthen rhizosphere colonization and suppress pathogens. These interactions contribute to microbial community recovery, an improved soil structure, and enhanced nutrient cycling. This review synthesizes current evidence on the molecular and physiological mechanisms by which PGPB enhance soil restoration in degraded agroecosystems, highlighting their role beyond biofertilization as key agents in ecological rehabilitation. It examines advances in nutrient mobilization, stress mitigation, and signaling pathways, based on the literature retrieved from major scientific databases, focusing on studies published in the last decade. Full article

The yak (Bos grunniens) is a key species in high-altitude rangelands of Asia. Despite their ecological and economic importance, yak production faces persistent challenges, including low milk yields, vulnerability to climate changes, emerging diseases, and a lack of systematic breeding programs. This review presents the genomic, physiological, and environmental dimensions of yak biology and husbandry. Genes such as EPAS1, which encodes hypoxia-inducible transcription factors, underpin physiological adaptations, including enlarged cardiopulmonary structures, elevated erythrocyte concentrations, and specialized thermoregulatory mechanisms that enable their survival at elevations of 3000 m and above. Copy number variations (CNVs) and single nucleotide polymorphisms (SNPs) present promising markers for improving milk and meat production, disease resistance, and metabolic efficiency. F1 and F2 generations of yak–cattle hybrids show superior growth and milk yields, but reproductive barriers, such as natural mating or artificial insemination, and environmental factors limit the success of these hybrids beyond second generation. Infectious diseases, such as bovine viral diarrhea and antimicrobial-resistant and biofilm-forming Enterococcus and E. coli, pose risks to herd health and food safety. Rising ambient temperatures, declining forage biomass, and increased disease prevalence due to climate changes risk yak economic performance and welfare. Addressing these challenges by nutritional, environmental, and genetic interventions will safeguard yak pastoralism. This review describes the genes associated with different yak traits and provides an overview of the genetic adaptations of yaks (Bos grunniens) to environmental stresses at high altitudes and emphasizes the need for conservation and improvement strategies for sustainable husbandry of these yaks. Full article

Water supply and sewage drainage pipes have a critical role to play in the provision of clean water and sanitation, and pipe material selection influences infrastructure life, water quality, and microbial communities. Zinc-containing compounds are highly valued due to their mechanical properties, anticorrosion behavior, and antimicrobial properties. However, the effect of zinc salts, such as zinc sulfate heptahydrate and zinc chloride, on biofilm-forming bacteria, including Escherichia coli and Enterococcus faecalis, is not well established. This study investigates the antibacterial properties of these zinc salts under simulated pipeline conditions using minimum inhibitory concentration assays, biofilm production assays, and antibiotic sensitivity tests. Findings indicate that zinc chloride is more antimicrobial due to its higher solubility and bioavailability of Zn²⁺ ions. At higher concentrations, zinc salts inhibit the development of a biofilm, whereas sub-inhibitory concentrations enhance the growth of biofilm, suggesting a stress response in bacteria. zinc chloride also enhances antibiotic efficacy against E. coli but induces resistance in E. faecalis. These findings highlight the dual role of zinc salts in preventing biofilm formation and modulating antimicrobial resistance, necessitating further research to optimize material selection for water distribution networks and mitigate biofilm-associated risks in pipeline systems. Full article