Microbial Cell Membrane Research Articles

Broad-spectrum antimicrobial activities of a food fermentate of Aspergillus oryzae.

The development of NP, a potent broad-spectrum antimicrobial, is a significant breakthrough in the ongoing challenge against microbial foodborne illnesses and the growing threat of antibiotic resistance. This food-grade culture broth of Aspergillus oryzae demonstrates exceptional broad-spectrum efficacy against a variety of harmful bacteria and fungi, including drug-resistant strains such as methicillin-resistant Staphylococcus aureus and prevalent food spoilage molds. NP exhibits strong bactericidal activity against various foodborne and ESKAPE pathogens, and strong antifungal activity against Penicillium species, Aspergillus fumigatus, and Candida albicans. The potent bactericidal and antifungal properties of NP are a result of its ability to disrupt microbial cell membranes leading to increased permeability. Furthermore, the genome-wide impact of NP on fungal gene expression and metabolic pathways underscores its comprehensive antimicrobial action, leading to transcriptomic and metabolic changes associated with cell death in A. fumigatus.

Multiplex antimicrobial activities of the self-assembled amphiphilic polypeptide β nanofiber KF-5 against vaginal pathogens

BackgroundVaginal infections caused by multidrug-resistant pathogens such as Candida albicans and Gardnerella spp. represent a significant health challenge. Current treatments often fail because of resistance and toxicity. This study aimed to synthesize and characterize a novel amphiphilic polypeptide, KF-5, and evaluate its antibacterial and antifungal activities, biocompatibility, and potential mechanisms of action.ResultsThe KF-5 peptide was synthesized via solid-phase peptide synthesis and self-assembled into nanostructures with filamentous and hydrogel-like configurations. Characterization by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) confirmed the unique nanostructural properties of KF-5. KF-5 (125, 250, or 500 µg/ml) demonstrated potent antibacterial and antifungal activities, with significant inhibitory effects on drug-resistant Candida albicans and Gardnerella spp. (P < 0.05). In vitro assays revealed that 500 µg/ml KF-5 disrupted microbial cell membranes, increased membrane permeability, and induced lipid oxidation, leading to cell death (P < 0.05). Cytotoxicity tests revealed minimal toxicity in human vaginal epithelial cells, keratinocytes, and macrophages, with over 95% viability at high concentrations. Molecular dynamics simulations indicated that KF-5 interacts with phospholipid bilayers through electrostatic interactions, causing membrane disruption. In vivo studies using a mouse model of vaginal infection revealed that 0.5, 1, and 2 mg/ml KF-5 significantly reduced fungal burden and inflammation, and histological analysis confirmed the restoration of vaginal mucosal integrity (P < 0.01). Compared with conventional antifungal treatments such as miconazole, KF-5 exhibited superior efficacy (P < 0.01).ConclusionsKF-5 demonstrates significant potential as a safe and effective antimicrobial agent for treating vaginal infections. Its ability to disrupt microbial membranes while maintaining biocompatibility with human cells highlights its potential for clinical application. These findings provide a foundation for further development of KF-5 as a therapeutic option for combating drug-resistant infections.

Nanotherapy for Cancer and Biological Activities of Green Synthesized AgNPs Using Aqueous Saussurea costus Leaves and Roots Extracts.

Background/Objectives: Nanoparticles derived from medicinal plants are gaining attention for their diverse biological activities and potential therapeutic applications. Methods: This study explored the antioxidant, anti-inflammatory, anti-tumoral, and antimicrobial properties of green synthesized silver nanoparticles (AgNPs) using the aqueous leaf and root extracts of Saussurea costus (S. costus). The physicochemical characterizations of both biosynthesized AgNPs using the aqueous leaf extract (L-AgNPs) and root extract (R-AgNPs) were examined using UV spectroscopy, fluorescence spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, dynamic light scattering, and Fourier-transform infrared spectroscopy. The antioxidant activity measured using ABTS, DPPH, and FRAP assays showed that AgNPs, particularly from roots, had higher activity than aqueous extracts, attributed to phenolic compounds acting as capping and antioxidant agents. Results: Enzyme inhibition studies indicated that AgNPs exhibited remarkable anti-inflammatory effects, inhibiting COX-1, 5-LOX, and secreted PLA2 enzymes by over 99% at 120 µg/mL, comparable to standard drugs. The anti-tumoral effects were evaluated on the human cancer cell lines HCT-116, LoVo, and MDA-MB-231, with AgNPs inhibiting cell proliferation dose-dependently and IC50 values between 42 and 60 µg/mL, demonstrating greater potency than extracts. The AgNPs also showed enhanced antimicrobial activities against various microbial strains, with IC50 values as low as 14 µg/mL, which could be linked to nanoparticle interactions with microbial cell membranes, causing structural damage and cell death. Conclusions: These findings suggest that S. costus-derived AgNPs are promising natural, biodegradable agents for various biological applications and potential new therapeutic agents, necessitating further research to explore their mechanisms and applications.

Silver Nanoparticles in Therapeutics and Beyond: A Review of Mechanism Insights and Applications.

Silver nanoparticles (NPs) have become highly promising agents in the field of biomedical science, offering wide therapeutic potential due to their unique physicochemical properties. The unique characteristics of silver NPs, such as their higher surface-area-to-volume ratio, make them ideal for a variety of biological applications. They are easily processed thanks to their large surface area, strong surface plasmon resonance (SPR), stable nature, and multifunctionality. With an emphasis on the mechanisms of action, efficacy, and prospective advantages of silver NPs, this review attempts to give a thorough overview of the numerous biological applications of these particles. The utilization of silver NPs in diagnostics, such as bioimaging and biosensing, as well as their functions in therapeutic interventions such as antimicrobial therapies, cancer therapy, diabetes treatment, bone repair, and wound healing, are investigated. The underlying processes by which silver NPs exercise their effects, such as oxidative stress induction, apoptosis, and microbial cell membrane rupture, are explored. Furthermore, toxicological concerns and regulatory issues are discussed, as well as the present difficulties and restrictions related to the application of silver NPs in medicine.

Potential of Flavonoids as Promising Phytotherapeutic Agents to Combat Multidrug-Resistant Infections.

Considering the limited number of current effective treatments, Multidrug- Resistant (MDR) illnesses have grown to be a serious concern to public health. It has become necessary to look for new antimicrobial drugs because of the emergence of resistance to numerous kinds of antibiotics. The use of flavonoids is one phytotherapeutic strategy that has been researched as a potential remedy for this issue. Secondary plant compounds called flavonoids have been found to have an antibacterial effect against resistant microorganisms. This review seeks to give readers a glimpse into contemporary studies on flavonoids' potential to fight MDR infections. A systematic search was conducted on electronic databases (PubMed, Scopus, and Google Scholar) using relevant keywords such as flavonoids, MDR infections, antimicrobial activity, and resistance microbes. Studies that investigated the antimicrobial activity of flavonoids against resistant microbes were included in this review. Most research found that flavonoids have antibacterial efficacy against resistant microorganisms, and some also showed that they have synergistic benefits with traditional antibiotics. The flavonoids quercetin, kaempferol, apigenin, and luteolin were the most often investigated ones. According to research, flavonoids affect microbial gene expression, inhibit microbial enzymes, and disrupt the integrity of microbial cell membranes. Additionally, a few studies have noted the flavonoids' low toxicity and safety. For the treatment of infections that are resistant to many drugs, flavonoids constitute a promising class of phytotherapeutic agents. To develop flavonoid-based treatment methods for treating MDR illnesses and assess the potential of flavonoids as adjuvants to conventional antimicrobial drugs, more study is required.

Differential interaction modes of As(III)/As(V) with microbial cell membrane induces opposite effects on organic contaminant biodegradation in groundwater

Arsenic, a widespread toxic metalloid in groundwater, derives both from natural geological environment and industrial discharge, is extensively detected to be coexisting with organic contaminants, such as 2,4,6-trichlorophenol (TCP), a prior concerned pollutant. During biological remediation of groundwater, arsenic potentially intervenes microbial behaviors. This study found an opposite interference of arsenic in its two different valences (III and V) on the degradation of TCP by the functional bacteria, Sphingomonas fennica K101. As(III) inhibited TCP degradation in a concentration-dependent manner (from 0.1-10 mg/L), with a maximum inhibition rate of 35.5 %, whereas As(V) exhibited promoting effects by 13.8 % and 33.2 % at 1 mg/L and 10 mg/L, respectively. Employing field emission transmission electron microscopy, quantum chemical calculation, fourier-transform ion cyclotron resonance mass spectrometry and metabolomic analysis, we unveil distinct interactions between cell membranes and arsenic in two valence states. Exposure to As(III) led to significant accumulation of As(III) in the cytoplasm, followed by interaction with intracellular ferritin (ferritin heavy chain 1), releasing iron ions and generating ROS. Subsequently, it induced ferroptosis and disrupted bacterial basal metabolism, thereby inhibiting TCP biodegradation. Oppositely, As(V) bound to a critical component sphingosine and triggered sphingosine polymerization, increasing membrane permeability, which was evidenced by measuring lactate dehydrogenase release. This process facilitated TCP transmembrane permeation by reducing membrane or extracellular secretion resistance. As(V) concurrently upregulated energy metabolism and accelerated TCP degradation. Our study elucidates the influence of prevalent arsenic on biodegradation efficacy, particularly amidst changing redox conditions associated with varying arsenic valences.

A novel strategy for Klebsiella sp. to resist high salt and high phenol environmental stress

Isolating high-performance phenol degradation microorganisms with high salt tolerance and studying their resistance mechanisms are urgent issues. To address these issues, a typical bacteria (Klebsiella sp. YP-1) with high salt and phenol tolerance was isolated. Its strategies for resisting high salt and high phenol stress were studied. The results indicated that Klebsiella sp. YP-1 was able to degrade 1000 mg/L phenol within 44 h at 70 g/L NaCl, which was faster than most microorganisms reported in the literature. Lyxose secreted by Klebsiella sp. YP-1 played an important role on assisting Klebsiella sp. YP-1 to resist stress. Lyxose increased phenol degradation rate by microorganisms due to its protection on cell membrane. Quantum chemical calculation results indicated that lyxose was more likely attacked by free radical than cell membrane. In addition, lyxose could bind to the cell membrane through hydrogen bonds. Thus, lyxose prevented reactive oxygen species from harming cell membranes. Moreover, lyxose has broad protective effect on microbial cell membranes. This study provides a novel idea for microorganisms to resist oxidative stresses.

A review of the synthesis and application of azo dyes and metal complexes for emerging antimicrobial therapies

Antimicrobial resistance presents a formidable challenge to contemporary medicine, necessitating innovative therapeutic solutions. Azo dyes and their metal complexes have emerged as promising candidates due to their notable antimicrobial properties. This review comprehensively examines the synthesis and application of azo dyes and metal complexes for emerging antimicrobial therapies. Through various synthetic strategies and metallation, the chemical structure of azo derivatives allows for modifications that enhance their antimicrobial efficacy, making them promising candidates for pharmaceutical development against microbial infections. The study provides a comprehensive understanding of the mechanisms of antimicrobial action, including DNA intercalation, enzyme inhibition, membrane disruption, and reactive oxygen species generation. The role of metal ions is particularly significant, enhancing structural stability, reactivity, and the ability to target microbial enzymes effectively. Chelation effects, such as reduced polarity and increased lipophilicity, facilitate the penetration of microbial cell membranes and the disruption of enzyme activity. The review highlights novel azo-metal complexes’ significant antifungal and antibacterial activities, particularly their efficacy against pathogens such as Mycobacterium tuberculosis. The importance of structure-activity relationships is detailed, showing how specific functional groups and metal ions influence antimicrobial efficacy. Additionally, their potential sensing ability to detect and identify microorganisms highlights the multifaceted role of azo dye derivatives in infection management.

The Effect of Irradiation on Meat Products.

The effects of irradiation on meat constituents including water, proteins, and lipids are multifaceted. Irradiation leads to the decomposition of water molecules, resulting in the formation of free radicals that can have both positive and negative effects on meat quality and storage. Although irradiation reduces the number of microorganisms and extends the shelf life of meat by damaging microbial DNA and cell membranes, it can also accelerate the oxidation of lipids and proteins, particularly sulfur-containing amino acids and unsaturated fatty acids. With regard to proteins, irradiation affects both myofibrillar and sarcoplasmic proteins. Myofibrillar proteins, such as actin and myosin, can undergo depolymerization and fragmentation, thereby altering protein solubility and structure. Sarcoplasmic proteins, including myoglobin, undergo structural changes that can alter meat color. Collagen, which is crucial for meat toughness, can undergo an increase in solubility owing to irradiation-induced degradation. The lipid content and composition are also influenced by irradiation, with unsaturated fatty acids being particularly vulnerable to oxidation. This process can lead to changes in the lipid quality and the production of off-odors. However, the effects of irradiation on lipid oxidation may vary depending on factors such as irradiation dose and packaging method. In summary, while irradiation can have beneficial effects, such as microbial reduction and shelf-life extension, it can also lead to changes in meat properties that need to be carefully managed to maintain quality and consumer acceptability.

The Potential o f Gold Nanobipyramids as Anti-Fungal f or Dermatophytes Fungi at Living Animals

Dermatophytes are a group of fungi that cause dermatophytosis, a type of skin infection affecting both humans and animals. While dermatophytosis is typically self-limiting, it can pose significant challenges for individuals with weakened immune systems. Additionally, current treatment options for dermatophytosis have their limitations, including issues of toxicity, inefficacy, and the emergence of drug-resistant strains. Recently, nanotechnology-based approaches have emerged as a promising strategy to overcome the drawbacks of conventional antifungal medications. Gold Nanoparticles (GNPs) have demonstrated substantial antifungal activity against various fungal species, including dermatophytes. Among these, Gold Nanobipyramids (GNBPs) exhibit unique physicochemical properties that enhance their effectiveness against dermatophytes. GNBPs were synthesized using the Seed-Mediated Growth Method (SMGM) due to its simplicity. Optically, GNBPs displayed plasmonic peaks at 1.548 (wavelength 561 nm) and 2.372 (wavelength 807 nm). Structurally, intensity peaks at 38.15° (plane 111) and 44.49° (plane 200) were identified. GNBPs have a surface density of ~70.227±0.530. In the dermatophyte treatment process, GNBPs exhibited varying inhibitory effects. At 40% concentration, fungal growth persisted, with a surface density similar to the no control area. At 60%, inhibition occurred, though less efficiently. The most effective inhibition was observed at 80%, and complete inhibition was achieved at 100% concentration. GNBPs proved successful in inhibiting fungal growth, attributed to their curvature and sharp edges interacting with microbial cell membranes, leading to membrane damage and cellular content leakage.

Bioactive metabolites from endophytes of African club moss- Selaginella kraussiana (Kunze) A. Braun exhibit broad-spectrum pharmaceutical utilities

The search for potent natural compounds from plant and microbial sources is increasing logarithmically to combat various types of health issues of which multidrug-resistant microbes and problems related to oxidative stress are the prime ones. Novel secondary metabolites from endophytes have always been potent alternatives to contemporary antimicrobials and antioxidants. The present study shows that two potent endophytic fungal isolates Ascochyta medicaginicola SK16 and Phomopsis sp. SK5 synthesises non-proteinaceous, thermostable secondary metabolites with broad-spectrum antimicrobial, antioxidative, and cytotoxic activity. Bioassay-guided fractionation revealed that the Ethyl acetate (EA) extract of the cell-free culture extract (CFCE) of SK5 and SK16 constitutes ten and eleven secondary metabolites of which 2,4, -di tert butyl phenol, aziridine- 1,2-amino ethyl, actinobolin, bactobolin, azulene, menthyl acetate, phenol, p-[2-(methylamino)ethyl], and imidazole components were significant. SK16 exhibited strong antimicrobial activity against seventeen pathogens including Methicillin-resistant Staphylococcus aureus (MRSA), and C. albicans with a minimum microbicidal concentration of 100- 400 µg mL−1. These metabolites disrupt the microbial cell membranes causing lethal leakage of biomacromolecules- nucleic acid, protein, and potassium ions. Enzymes involved in the EMP pathway, TCA cycle, and gluconeogenesis were also blocked. Both the biofilm formation and transition of Candida cells from the yeast-to-hyphal form were inhibited. SK5 metabolites are potent radical scavengers with an IC50 of 34.25 ± 0.87 – 195.21 ± 5.73 µg mL−1 against DPPH, ABTS, FRAP, and H2O2 free radical generators and significantly increased antioxidant parameters in treated peritoneal macrophage cells of male Wistar rats. Also, SK5 metabolites were cytotoxic against breast (T47D), pancreatic (MIA Paca-2), lung (A549) and colon (HCT-116) cancer cells. The present findings suggest that metabolites from endophytes of African club moss hold potent pharmaceutical utilities.

Silver Nanoparticles as Antimicrobial Agents: Mechanisms, Challenges, and Applications

Silver nanoparticles (AgNPs) have garnered considerable attention for their potent antimicrobial properties and broad spectrum of applications in various fields. This review delves into the multifaceted realm of AgNPs as antimicrobial agents, aiming to provide a comprehensive understanding of their mechanisms of action, challenges, and diverse applications. The article begins by tracing the historical significance of silver as an antimicrobial agents and transitions into the contemporary role of AgNPs in modern applications. The synthesis of AgNPs is explored, encompassing diverse methods such as chemical, physical, and biological approaches. Particular emphasis is placed on green synthesis methods, which not only yield nanoparticles with controlled properties but also align with principles of environmental sustainability and biocompatibility. The review subsequently dissects the intricate mechanisms underpinning AgNPs antimicrobial process. The interaction of AgNPs with microbial cell membranes, generation of reactive oxygen species (ROS), and disruption of vital microbial processes collectively contribute to their potent bactericidal and fungicidal activities. However, the incorporation of AgNPs into various applications is not devoid of challenges. This article examines potential toxicity concerns, addressing issues related to stability, aggregation, and controlled release of nanoparticles, as well as the emergence of resistance mechanisms in microorganisms. Delving into the realm of applications, the review unveils AgNPs’ significance in biomedical and clinical settings, where they are employed in wound healing, medical devices, and infection control. Moreover, the environmental implications of AgNPs are explored, including their use in water and air purification, as well as potential roles in food and agricultural sectors. Looking forward, the review discusses emerging trends and suggests future research directions. Combinational therapies, integration with advanced materials, and exploration of AgNPs’ potential in addressing global antimicrobial resistance are outlined as promising avenues. In conclusion, this comprehensive review underscores the vital role of silver nanoparticles as versatile and potent antimicrobial agents, shedding light on their mechanisms, challenges, and multifarious applications across diverse sectors.

Novel design of simplified β-hairpin antimicrobial peptide as a potential food preservative based on Trp-pocket backbone

Food contamination from microbial deterioration requires the development of potent antimicrobial peptides (AMPs). The deployment of approved AMPs as dietary preservatives is limited due to barriers such as instability, toxicity, and high synthetic costs. This exploration utilizes the primary structural elements of the Trp-pocket backbone to engineer a series of β-hairpin AMPs (XWRWRPGXKXXR-NH2, X representing I, V, F, and/or L). Peptides WpLF, with Phe as X and Leu arranged at the 11th position, demonstrated exceptional selectivity index (SI = 123.08) and sterilization effects both in vitro and in vivo. WpLF consistently exhibited stable bacteriostasis, regardless of physiological salts, serum, and extreme pH. Mechanistic analysis indicated that the peptide penetrates microbial cell membranes, inducing membrane disruption, thereby impeding drug resistance evolution. Conclusively, AMPs engineered by the Trp-pocket skeleton hold substantial potential as innovative biological preservatives in food preservation, providing valuable insights for sustainable and safe peptide-based food preservatives.

Towards zero excess sludge discharge with built-in ozonation for wastewater biological treatment

In this study, a biological treatment process, which used a built-in ozonation bypass to achieve sludge reduction, was built to treat the industrial antifreeze production wastewater (mainly composed of ethylene glycol). The results indicated there is a positive correlation between ozone dosage and sludge reduction. At the laboratory level, the MLSS in the system can be stably controlled at around 3400 mg MLSS L−1 under the dosage of 0.18 g O3 g−1 MLSS. Ozonation can increase the compactness of sludge flocs (fractal dimension increased from 1.89 to 1.92). Ozone destroys microbial cell membranes and alters the structure of sludge flocs through direct oxidation through electrophilic reactions. It leads to the release of intracellular polysaccharides, proteins, and other biological macromolecules in microorganisms, thereby promoting the implicit growth of microbial populations. Some bacteria such as g_Pseudomonas, g_Gemmobacter, etc. have strong ethylene glycol degradation ability and tolerance to ozonation. The removal of ethylene glycol includes the glyoxylate cycle, glycine serine carbon cycle, and the glutamate-cysteine ligase pathway of assimilation. Gene KatG and gpx may be key factors in improving microbial tolerance to ozonation. The comprehensive evaluation from the perspectives of cost and carbon emission shows that choosing ozone cracking-implicit growth in wastewater treatment systems has significant cost advantages and application value.

Exploring the effects of diverse extraction methods on nanoemulsion formulation using betel leaf essential oil: Assessing antibacterial efficacy against pathogenic microorganisms

The present study focused on observing the impact of different pretreatments applied on betel leaves powder (BLP) before extraction of essential oil (EO) on the formulation and characterization of BLP-EO-nanoemulsion (NE). BLP-EO nanoemulsion was produced from different BLP-EO (C, CP, MW, CPAMW treated BLP-EO), surfactant (tween 80), and distilled water by ultrasonic probe method and their particle size, polydispersity index (PDI), zeta potential, turbidity, viscosity, refractive index, whiteness index and antibacterial properties were investigated. Significant differences were observed among the nanoemulsions prepared from EO obtained using different pretreatment. The CPAMW-BLP-EO- nanoemulsion prepared with 1% oil concentration and 1:3 oil to surfactant concentration showed the smallest particle size (98.00 ± 0.92 nm), lowest PDI value (0.21 ± 0.01) and zeta potential value (−24.73 ± 1.37) followed by MW, CP and C-BLP-EO-NE due to high concentration of chemical composition that effectively bind with a surfactant. Similarly, better physical properties were obtained for CPAMW-BLP-EO-NE. This CPAMW treated BLP-EO nanoemulsion was the most effective against Gram-positive bacteria like Staphylococcus aureus with an inhibition zone of 12.5 mm than Gram-negative bacteria like Salmonella spp and Escherichia coli with an inhibition zone of 9.4 mm, and 8.5 mm respectively followed by MW, CP, and C treated BLP-EO-NE. In conclusion, the potent antibacterial activity of the nanoemulsion is due to its higher concentration of oxygenated terpenoids and smaller particle size, facilitating effective transport of active compounds and enhancing interactions with microbial cell membranes. Therefore, the CPAMW pre-treated BLP-EO nanoemulsions showed great potential to be incorporated into water-based food products and beverages as flavoring and antimicrobial agents.

Antimicrobial effects of catnip (Nepeta cataria L.) essential oil against canine skin infection pathogens

Background and Aim: Catnip essential oils have antimicrobial effects against bacteria, yeast, and fungi; however, there is limited information regarding their antimicrobial activity against pathogens that cause canine skin infections. This study aimed to identify the phytochemical constituents of catnip essential oil and assay its antimicrobial activity against Staphylococcus pseudintermedius, Malassezia pachydermatis, Microsporum canis, Microsporum gypseum, Microsporum gallinae, and Trichophyton mentagrophytes. Materials and Methods: Catnip essential oil was extracted by hydrodistillation, and its chemical constituents were analyzed by gas chromatography–mass spectrometry (GC–MS). In vitro antimicrobial activity was investigated using broth microdilution and time-kill tests. To evaluate the effect of catnip essential oil on microbial morphology and cell membrane integrity, scanning electron microscopy (SEM) and leakage studies were conducted. Results: GC–MS analysis revealed that the principal components of catnip essential oil were cis- and trans-nepetalactone (57.09% of peak area), trans-, cis-nepetalactone (39.69% of peak area), trans-caryophyllene (1.88% of peak area), and caryophyllene oxide (1.34% of peak area). The minimum inhibitory concentration, minimum bactericidal concentration, and minimum fungicidal concentration values determined by broth microdilution ranged from 0.0625 mg/mL to 4.0 mg/ mL. Time-kill testing showed that the germicidal effects of catnip essential oil were time and concentration-dependent, respectively. Environmental SEM and cell leakage analysis indicated that catnip essential oil disrupted the integrity of cell membranes in the tested microorganisms. Conclusion: Catnip essential oil has potential as an alternative antimicrobial against a wide range of canine skin infection pathogens, including S. pseudintermedius, M. pachydermatis, Mi. canis, Mi. gypseum, Mi. gallinae, and T. mentagrophytes. Keywords: antimicrobial activity, canine dermatitis, catnip, Nepeta cataria.

Harnessing the potential of bimetallic nanoparticles: Exploring a novel approach to address antimicrobial resistance.

The growing global importance of antimicrobial resistance (AMR) in public health has prompted the creation of innovative approaches to combating the issue. In this study, the promising potential of bimetallic nanoparticles (BMNPs) was investigated as a novel weapon against AMR. This research begins by elaborating on the gravity of the AMR problem, outlining its scope in terms of the effects on healthcare systems, and stressing the urgent need for novel solutions. Because of their unusual features and wide range of potential uses, bimetallic nanoparticles (BMNPs), which are tiny particles consisting of two different metal elements, have attracted a lot of interest in numerous fields. This review article provides a comprehensive analysis of the composition, structural characteristics, and several synthesis processes employed in the production of BMNPs. Additionally, it delves into the unique properties and synergistic effects that set BMNPs apart from other materials. This review also focuses on the various antimicrobial activities shown by bimetallic nanoparticles, such as the rupturing of microbial cell membranes, the production of reactive oxygen species (ROS), and the regulation of biofilm formation. An extensive review of in vitro studies confirms the remarkable antibacterial activity of BMNPs against a variety of pathogens and sheds light on the dose-response relationship. The efficacy and safety of BMNPs in practical applications are assessed in this study. It also delves into the synergistic effects of BMNPs with traditional antimicrobial drugs and their ability to overcome multidrug resistance, providing mechanistic insight into these phenomena. Wound healing, infection prevention, and antimicrobial coatings on medical equipment are only some of the clinical applications of BMNPs that are examined, along with the difficulties and possible rewards of clinical translation. This review covers nanoparticle-based antibacterial regulation and emerging uses. The essay concludes with prospects for hybrid systems, site-specific targeting, and nanoparticle-mediated gene and drug delivery. In summary, bimetallic nanoparticles have surfaced as a potential solution, offering the public a more promising and healthier future.

Identification of polyphenol extracts from flaxseed and study on its bacteriostatic mechanism

In this paper, the polyphenol components of flaxseed were identified, and their antibacterial effect and mechanism of action against pathogenic bacteria were studied. Results showed that 14 phenolic acids and 15 flavonoids were identified in flaxseed. Among them, 5 phenolic acids, including ferulic acid, vanillic acid, sinapic acid, gallic acid, 4-hydroxybenzoic acid, as well as 6 flavonoids, including vitexin, quercitrin, quercetin, apigenin, kaempfero1, (+)-dihydroquercetin, were the main phenolic compounds in flaxseed and have been quantitatively analyzed and determined. The content of sinapic acid and quercetin accounted for over 42.67% of flaxseed polyphenol extract. The Oxford Cup method confirmed the antibacterial effect of flaxseed polyphenol extract on Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Salmonella and Pseudomonas fluorescens. The experimental data showed that flaxseed polyphenol extract had a strong inhibitory effect on the growth of both common food-borne pathogens and non-food-borne pathogens. Flaxseed polyphenols increased the permeability of microbial cell membrane, resulting in microbial protein leakage, cell membrane depolarization, and decreased intracellular ATP content, and increased cell membrane potential and cell contents leakage. The results of this study clarified the composition of flaxseed polyphenol and provided a new way for the comprehensive utilization of flaxseed.

Photoinduced force microscopy as a novel method for the study of microbial nanostructures.

A detailed comparison of the capabilities of electron microscopy and nano-infrared (IR) microscopy for imaging microbial nanostructures has been carried out for the first time. The surface sensitivity, chemical specificity, and non-destructive nature of spectroscopic mapping is shown to offer significant advantages over transmission electron microscopy (TEM) for the study of biological samples. As well as yielding important topographical information, the distribution of amides, lipids, and carbohydrates across cross-sections of bacterial (Escherichia coli, Staphylococcus aureus) and fungal (Candida albicans) cells was demonstrated using PiFM. The unique information derived from this new mode of spectroscopic mapping of the surface chemistry and biology of microbial cell walls and membranes, may provide new insights into fungal/bacterial cell function as well as having potential use in determining mechanisms of antimicrobial resistance, especially those targeting the cell wall.

Cholic Acid-Derived Gemini Amphiphile Can Eradicate Interkingdom Polymicrobial Biofilms and Wound Infections.

Biofilm infections are mainly caused by Gram-positive bacteria (GPB) like Staphylococcus aureus, Gram-negative bacteria (GNB) like Pseudomonas aeruginosa, and fungi like Candida albicans. These infections are responsible for antimicrobial tolerance, and commensal interactions of these microbes pose a severe threat to chronic infections. Treatment therapies against biofilm infections are limited to eradicating only 20-30% of infections. Here, we present the synthesis of a series of bile acid-derived molecules using lithocholic acid, deoxycholic acid, and cholic acid where two bile acid molecules are tethered through 3'-hydroxyl or 24'-carboxyl terminals with varying spacer length (trimethylene, pentamethylene, octamethylene, and dodecamethylene). Our structure-activity relationship investigations revealed that G21, a cholic acid-derived gemini amphiphile having trimethylene spacer tethered through the C24 position, is a broad-spectrum antimicrobial agent. Biochemical studies witnessed that G21 interacts with negatively charged lipoteichoic acid, lipopolysaccharide, and phosphatidylcholine moieties of GPB, GNB, and fungi and disrupts the microbial cell membranes. We further demonstrated that G21 can eradicate polymicrobial biofilms and wound infections and prevent bacteria and fungi from developing drug resistance. Therefore, our findings revealed the potential of G21 as a versatile antimicrobial agent capable of effectively targeting polymicrobial biofilms and wound infections, suggesting that it is a promising antimicrobial agent for future applications.