Chlorinated derivatives of picolinic acid are a group of chemical compounds commonly used as a component of plant protection products (herbicides) applied against weeds. This study examined the structural properties, microbiological activity, and cytotoxicity of picolinic acid and its four derivatives: clopyralid, aminopyralid, picloram, and triclopyr. Structural analysis was performed using spectroscopic methods: FTIR, Raman, and UV-VIS spectroscopy. The research was supported by theoretical calculations using quantum chemistry methods. The calculations of electronic charge distribution, electrostatic potential maps, HOMO and LUMO frontier orbital energies, and global reactivity descriptors were performed to characterize the electronic properties and relative reactivity of the studied compounds. Microbiological activity was tested against soil bacterial strains (Arthrobacter psychrolactophilus ATCC 700733, Bacillus megatherium ATCC 14581, Pseudomonas aeruginosa ATCC 15442, and Serratia liquefaciens ATCC 27592). Cytotoxicity studies were performed on normal human fibroblasts (BJ, ATCC CRL-2522), colorectal adenocarcinoma cells (Caco-2, ATCC HTB-37) and immortalized human keratinocytes (HaCaT, Cytion 300493). Tests were also conducted to assess the herbicides' susceptibility to thermal decomposition and to analyse thermal decomposition products. TG/FTIR analyses were used for this purpose.

Thymus algeriensis (T. algeriensis), a North African thyme species, exhibits notable antimicrobial potential. This study evaluated the antibacterial activity of its essential oil (EO) and assessed its application in active cellophane packaging for chicken meat preservation. The EO was impregnated onto cellophane sheets and applied in situ on chicken thighs artificially contaminated with Escherichia coli ATCC 25,922 (E. coli) and stored at 5 ± 1 °C for 96 h. The EO chemical composition was determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Antimicrobial activity was assessed in vitro using disc-diffusion, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) assays against E. coli, Staphylococcus aureus ATCC 25,923 (S. aureus), Candida albicans ATCC 71,453 (C. albicans), and Aspergillus niger ATCC 16,404 (A. niger). Results showed a marked reduction in microbial load in EO-treated samples compared with controls, demonstrating the effectiveness of EO-based active packaging in inhibiting bacterial growth under refrigerated storage. These findings support the potential of T. algeriensis EO as a bioactive natural preservative for active food packaging systems to enhance food safety and extend shelf life.

This study aimed to evaluate the antibacterial and antivirulence activities of Piper betle essential oil (PP) against Staphylococcus aureus and to investigate its effects on resistance development, antibiotic susceptibility, and quorum-sensing-associated virulence during prolonged exposure. S. aureus ATCC 25,923 was subjected to a 30-day laboratory adaptive evolution under sub-inhibitory exposure to PP or conventional antibiotics (chloramphenicol, streptomycin, and kanamycin). Prolonged antibiotic exposure resulted in high-level resistance, extensive cross-resistance, and upregulation of quorum-sensing- and virulence-associated genes, including agrA, luxS, hla, and hlb. By contrast, 30 days of PP exposure produced no detectable increase in PP MIC or cross-resistance and was associated with maintained or enhanced antibiotic susceptibility. PP-adapted populations exhibited increased rot transcription together with reduced expression of quorum-sensing-, toxin-, and biofilm-associated genes. In both wild-type and antibiotic-adapted populations, PP enhanced antibiotic susceptibility, with 4- to 32-fold reductions in MIC/MBC values observed in antibiotic-adapted populations. Supplementation with exogenous AI-2 partially restored resistance, suggesting that modulation of the LuxS/AI-2 system contributes to PP-mediated antibiotic re-sensitisation, although it may not represent the sole or predominant mechanism. Collectively, these in vitro findings indicate that PP can potentiate antibiotic activity and attenuate virulence-associated phenotypes without a detectable increase in PP resistance during the 30-day experimental period. Validation in MRSA and genetically diverse clinical isolates is required before broader therapeutic conclusions can be drawn.

The present study investigated the fatty acid composition of Linum strictum seed oil and evaluated its antibacterial, antibiofilm, anticoagulant, and α-amylase inhibitory activities. The oil was extracted from commercially obtained seeds and characterized by GC-FID. Antibacterial activity was determined using the microbroth dilution method, while antibiofilm activity was assessed against multidrug-resistant strains, including Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), and Acinetobacter baumannii. Anticoagulant effects were evaluated using prothrombin time (PT) and activated partial thromboplastin time (aPTT), and α-amylase inhibition was assessed in vitro. The oil was characterized by a high proportion of unsaturated fatty acids, mainly α-linolenic (57.08%), oleic (17.53%), and linoleic (14.0%) acids. Significant antibacterial activity was observed against Enterococcus faecalis ATCC 29212 and A. baumannii A2553 and A722 (MIC = 1.25 mg/mL), while three S. aureus strains showed MIC values of 5 mg/mL. Biofilm inhibition exceeded 70% against A. baumannii at 2×MIC. The oil prolonged coagulation times, particularly through the intrinsic pathway (PT = 16.4 s; aPTT = 81.6 s). α-Amylase inhibition reached 85.98% (IC50 = 0.0134 mg/mL), comparable to acarbose. Molecular docking revealed favorable binding of α-oleic acid to BEL-1 β-lactamase and α-linolenic acid to DNA gyrase B.

This study evaluated the antibacterial effect of photodynamic therapy (aPDT) using nanomicelle-encapsulated curcumin photosensitizer (PS) against drug-resistant clinical isolates of Klebsiella pneumoniae and K. pneumoniae ATCC 13883[™]. In this study, nanomicelle curcumin prepared by the thin film hydration method, with LED as the radiation source, was used for effective aPDT. The technique's effectiveness was analysed through membrane changes tracked by flow cytometry, bacterial structural alterations observed via FTIR, lipid peroxidation quantification assay, atomic force microscopy, and its performance against 17 clinical isolates resistant to cephalosporins and carbapenems was evaluated. Based on the results of aPDT, the minimum inhibitory concentration of the PS was 200 μg/mL for the standard strain and 125-1000 μg/mL for superbug clinical isolates. With an irradiation dose of 500 J/cm[2], an irradiation time of 500 s, and a power density of 1000 mW/cm[2] from an LED, bacterial growth was inhibited by a mean of 8 Log10 CFU/mL reduction, as determined by the culture method. Additionally, the results of the bacterial structural integrity assays (flow cytometry, FTIR, MDA levels, and AFM) for the standard strain provided convergent evidence with the culture results. This study demonstrates antibacterial activity of LED-illuminated curcumin nanomicelles against multidrug-resistant K. pneumoniae.

Bioactive wound dressings with antibacterial properties are attractive for infection control. Phytochemicals, products from plant secondary metabolism, like gallic acid (GA), ferulic acid (FA), coumaric acid (CouA) and perillyl alcohol (PA) show promising antimicrobial activity, but their poor water solubility and the high concentrations required for efficacy limit their application. To overcome this, Natural Deep Eutectic Solvents (NADES) provide a sustainable and biocompatible alternative to conventional solvents. NADES were used at sub-minimum bactericidal concentrations (MBC) to enhance phytochemical antimicrobial activity against Staphylococcus epidermidis and Escherichia coli. CC:Gly (100%) dissolved all tested phytochemicals. GA + CC:Gly:CA (20%) against S. epidermidis, and AP, CouA and FA with CC:Gly (100%) against E. coli, reduced the MBC from ≥4000 to 2000 μg/mL. The most promising phytochemical-NADES formulations were encapsulated into electrospun zein nanofibres to fabricate sustainable bioactive wound dressings. All electrospinning solutions exhibited Newtonian behaviour, and their viscosity and conductivity strongly influenced fibre morphology: CC:Gly formulations produced rough fibres with larger diameters (1253 ± 57 nm), whereas CC:Gly:CA yielded smooth fibres with smaller diameters (419 ± 45 nm). In vitro release studies demonstrated complete GA release within 50 min, following a non-Fickian diffusion. FTIR indicated encapsulation through physical entrapment. Among the antimicrobial assays performed, disk diffusion demonstrated the most evident activity, with Z + GA + CC:Gly:CA producing an inhibition zone of 18.7 mm, although further optimisation is required to improve performance in liquid-based assays. Overall, this study demonstrates the role of NADES as phytochemical solubilisers and antimicrobial enhancers, as well as functional components of electrospun sustainable wound dressing applications.

Limosilactobacillus reuteri is a promising probiotic species, yet strain-specific properties must be thoroughly characterized to ensure safety and efficacy. In this study, we isolated L. reuteri MKLQ3807-13 from the feces of a healthy Kunming dog and evaluated its probiotic potential through integrated genomic and phenotypic analyses. Whole-genome sequencing revealed that MKLQ3807-13 possessed a single 2.05 Mb circular chromosome, lacked plasmids, and harbored genes associated with acid and bile tolerance, adhesion, antimicrobial production, antioxidant activity, and γ-aminobutyric acid (GABA) biosynthesis. Phenotypic characterization showed that MKLQ3807-13 exhibited strong tolerance to acidic conditions (88.21% survival at pH 2.0) and bile salts (96.43% survival at 0.3%), high cell-surface hydrophobicity (76.28%), strong adhesion to HT-29 cells (18.71%), and substantial co-aggregation with Escherichia coli K88, Salmonella Typhi, Staphylococcus aureus ATCC 49,521, and Listeria monocytogenes BNCC 336,877. The strain demonstrated a broad spectrum of antimicrobial activity, attributed to organic acid production and a putative bacteriocin gene cluster, along with extracellular antioxidant activity. Furthermore, MKLQ3807-13 produced GABA in a time-dependent manner, reaching 36.36 µmol/mL after 48 h. Notably, safety evaluations showed no hemolytic activity, an absence of biogenic amine production, and no detectable virulence or horizontally transferable antibiotic resistance genes. These comprehensive findings indicate that L. reuteri MKLQ3807-13 possesses desirable probiotic attributes and a favorable safety profile, supporting its potential as a functional probiotic candidate for canines and other hosts.

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype characterized by dysregulated PI3K/Akt signaling and hypoxia-induced angiogenesis, and it lacks estrogen, progesterone, and HER2 receptors. Plant-derived lupeol has been reported to modulate the PI3K/Akt and HIF-1α/VEGF pathways, although the influence of aquatic environmental conditions on their biological activity remains poorly understood. This study investigated how river water quality affects lupeol stability and its cytotoxic and signaling-modulating effects in TNBC cells. River samples representing pollution gradients were analyzed for electrical conductivity (145-820 µS/cm), total dissolved solids (95-540 mg/L), heavy metals (ΣCd, Pb, Hg, As: 0.02-0.38 mg/L), and polycyclic aromatic hydrocarbons (0.01-0.21 µg/L). Lupeol was conditioned in these waters before treatment of MDA-MB-231 and BT-549 cells. Lupeol incubated in relatively clean upstream water retained > 92% stability, reduced VEGF by 60-65%, inhibited Akt phosphorylation by approximately 58% (p < 0.001), decreased HIF-1α expression by 65-70%, increased apoptosis by 35-40%, and reduced cell viability by 50-60%. In contrast, conditioning in polluted downstream water reduced lupeol stability to approximately 70%, limited Akt inhibition to approximately 25%, decreased HIF-1α suppression to 30-40%, and reduced apoptosis to 15-20%. Pollution indicators correlated strongly with diminished pathway modulation (r = - 0.86 to - 0.88), while multivariate analysis explained 82% of the observed variation (R[2] = 0.82). These findings demonstrate that river water chemistry influences lupeol stability and its cytotoxic and pathway-modulating effects in TNBC cells under in vitro conditions. However, because the present study was limited to TNBC cell lines, the results do not establish cancer-selective activity or therapeutic efficacy. Future studies should incorporate appropriate normal or non-tumorigenic cell models to assess selectivity and in vivo models to evaluate pharmacological efficacy, systemic toxicity, and translational potential.

The indiscriminate use of antibiotics has exacerbated the clinical challenge posed by Klebsiella pneumoniae, with persisters often evading antibiotic treatment. To investigate the mechanisms underlying persister formation, we identified the phosphate transporter gene phoU as differentially expressed during persister emergence and recovery. Using CRISPR-Cas9 gene editing, we created a ∆phoU knockout strain in K. pneumoniae ATCC 700603, along with its complemented (CphoU) and various overexpression strains (OE phoU, OE metE, and OE phoA). While growth rates and antibiotic susceptibility remained unchanged in the ∆phoU strain, its capacity to form persisters under levofloxacin and tobramycin stress was significantly reduced. Metabolomic and transcriptomic analyses linked phoU deletion to downregulation of metE (involved in methionine synthesis) and phoA (encoding alkaline phosphatase). ∆phoU also exhibited impaired biofilm formation and reduced extracellular polymeric substance (EPS) production compared to WT, CphoU, and the OE metE and OE phoA overexpression strains. Complementation of metE or phoA partially restored both biofilm formation and persister levels. Importantly, the reduction in persisters is primarily attributed to metabolic defects in planktonic cells-specifically, impaired methionine synthesis and stress response-rather than to reduced biofilm mass, which is considered a parallel phenotype. We conclude that PhoU promotes K. pneumoniae persistence by transcriptionally upregulating metE and phoA, thereby supporting the stress response capacity of planktonic cells. This study elucidates a novel pathway for persister formation and identifies PhoU and its downstream targets as potential therapeutic vulnerabilities.

The study of acetic acid (AA) stress in yeast is crucial for understanding the mechanisms of acid stress tolerance and enhancing production efficiency. Although AA toxicity has been extensively studied, the mechanism by which oxygen availability modulates ion flux balance and intracellular proton handling under AA stress remains poorly understood. Here, we investigated the combined effects of AA concentration, acidic pH, and oxygen availability on plasma membrane Na[+], K[+], and H[+] fluxes, intracellular pH, and growth in two Saccharomyces cerevisiae strains with distinct AA tolerance. We show that AA toxicity is strongly concentration-, strain-, and oxygen-dependent. AA exposure increased DCCD-sensitive proton (JH[+]) and sodium (JNa[+]) fluxes while progressively impairing potassium uptake (JK[+]), resulting in nonlinear, strain-specific shifts in Na[+]/H[+] and K[+]/H[+] exchange ratios and a substantial increase in ion exchange imbalance. These effects were amplified under oxygen-limited conditions and correlated with reduced growth and metabolic activity. Moderate AA stress was accompanied by increased intracellular ATP, particularly in ATCC 9804 under oxygen limitation, whereas severe AA stress caused ATP depletion, most strongly in ATCC 13007. Notably, the more tolerant strain maintained lower intracellular proton accumulation and more efficient ion flux coordination, particularly during aerobic growth. Together, our findings demonstrate that oxygen availability fundamentally reshapes ion flux balance and intracellular pH homeostasis during AA stress. These insights have direct implications for strain selection and process optimization in industrial fermentations exposed to weak organic acid inhibition.

The skin microbiota is linked to conditions such as acne. As antibiotic resistance limits the effectiveness of conventional treatments, microbiome-based strategies are needed. This study aimed to optimize the biomass production of Weissella paramesenteroides M4, evaluate its antioxidant properties, and assess its efficacy in a topical gel formulation against Cutibacterium acnes. Growth dynamics were established, followed by biomass optimization using fractional factorial and central composite rotatable designs with deproteinized whey as a sustainable substrate. Optimization increased biomass production by 974% (reaching 8.7 × 10[10] CFU/mL, equivalent to 2.031 g/L dry weight under validated conditions); significant variables included yeast extract, peptone, and MnSO4. Antioxidant assays showed activities of 80% (intact cells) and 61% (lysed cells), with 82% relative growth under 1.0 mM H2O2 oxidative stress (estimated spectrophotometrically). Notably, W. paramesenteroides M4 selectively inhibited the pathogen C. acnes ATCC 6919 in vitro without affecting the commensal S. epidermidis ATCC 12,228 in vitro. A cosmetic gel containing the strain maintained antimicrobial efficacy and stability for 15 days at 4 °C. W. paramesenteroides M4 demonstrates high bioprocess efficiency, robust antioxidant potential, and selective in vitro antimicrobial activity. The formulated gel containing the candidate probiotic strain retained antimicrobial activity under refrigeration during storage and shows potential for innovative topical applications, providing a preliminary foundation for alternative acne management. This research provides a sustainable framework for high-yield probiotic production using industrial by-products and introduces a potentially probiotic lactic acid bacterium with selective in vitro activity, representing a promising candidate for alternative acne treatment, addressing a significant gap in current dermatological therapies.