International Microbiology最新文献

{"title":"Enhancing the antifungal and antioxidant activity of Agaricus bisporus extract using gamma radiation: implications for shelf-life extension of fresh-cut apples.","authors":"Mohamed S Abd El-Al, Doaa A Emam, Eman Araby, Abeer A Khattab","doi":"10.1007/s10123-026-00806-3","DOIUrl":"10.1007/s10123-026-00806-3","url":null,"abstract":"<p><p>Fresh-cut fruits are highly perishable due to enzymatic browning and microbial spoilage following tissue disruption. This study investigated whether γ-irradiation of the edible mushroom Agaricus bisporus enhances its antioxidant and antifungal properties and whether the treated extract can be applied as a natural preservative for fresh-cut apples. Ethanolic extracts of A. bisporus were irradiated at 0-8.0 kGy and evaluated against six apple-spoiling fungi (Penicillium expansum, P. chrysogenum, Botrytis cinerea, Fusarium oxysporum, Aspergillus flavus, and A. niger). Among the tested solvents, ethanol yielded the most potent extract, showing a 14-mm inhibition zone against P. chrysogenum. Irradiation at 6.0 kGy significantly increased total phenolic content (3.25 mg GAE g⁻¹) and DPPH scavenging activity (46.3% at 100 µg mL⁻¹) (p < 0.05). The 6.0 kGy extract inhibited fungal enzymes-protease (40%), cellulase (35%), and lipase (45%)-and caused hyphal deformation, as observed by SEM. Sorbitol protection assays indicated cell-wall targeting. GC-MS profiling revealed irradiation-induced modifications in the fatty acid and sterol compositions. When applied at 10% (w/v) to fresh-cut apples stored at 4 °C for 10 days, the irradiated extract reduced browning, retained firmness, and decreased fungal and bacterial counts by 1.3 and 1.6 log CFU g⁻¹, respectively. Overall, mild γ-irradiation (6.0 kGy) enhanced the bioactivity and preservative potential of A. bisporus extract, supporting its application as a natural, clean-label agent for fresh-cut produce preservation.</p>","PeriodicalId":14318,"journal":{"name":"International Microbiology","volume":" ","pages":"1107-1120"},"PeriodicalIF":2.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13653835/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147815328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transcutaneous electrical nerve stimulation changed the relative abundance of intestinal microbiota in rats with knee osteoarthritis: a potential treatment for KOA.","authors":"Yang Zhang, Tong Ma, Ran Chen, Hong-Bin Zhao, Yan Sun","doi":"10.1007/s10123-026-00854-9","DOIUrl":"10.1007/s10123-026-00854-9","url":null,"abstract":"<p><strong>Background: </strong>Knee osteoarthritis (KOA) is a common degenerative bone disease, and transcutaneous electrical nerve stimulation (TENS) is an alternative and complementary therapy (ACM). This study revealed the role of TENS in regulating the intestinal microbiota in KOA rats.</p><p><strong>Methods: </strong>This study concentrated on the intestinal microbiota of KOA rats which were treated with TENS for 1, 2, and 3 weeks. Three intensities of TENS were used to treat KOA rats, and the expressions of IL6/8, PI3K-AKT were measured. The intestinal microbiota was analyzed by 16 S rDNA sequencing.</p><p><strong>Results: </strong>Compared with the Model Control group, TENS could improve symptoms of KOA rats and inhibit the expressions of IL6/8 by down-regulating the PI3K-AKT expression. After 3 weeks of treatment with TENS, compared with the Model Control group, the abundances of Bacteroidetes, Bacteroidetes, and Thermodesulfobacteria increased in the TENS groups; the abundances of Ficmicutes, Campylobacter, and Verruca decreased in the TENS groups.</p><p><strong>Conclusion: </strong>TENS could improve the histomorphology of knee and inhibit inflammation in KOA rats. After treatment with TENS, the intestinal microbiota gradually changed from 1,2,3 weeks and the abundance of them was different with three intensities of TENS. Further study will elucidate the underlying mechanisms of TENS in altering gut microbiota and the potential therapeutic applications of these intestinal microbiota for KOA.</p>","PeriodicalId":14318,"journal":{"name":"International Microbiology","volume":" ","pages":"1357-1366"},"PeriodicalIF":2.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13653860/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148301767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rosemary essential oil nanoparticles enhance antimicrobial activity and induce bacterial DNA disruption.","authors":"Habiba A Ahmed, Hala El-Adawi, Asmaa Abdel-Fattah, Abeer E Abd El-Wahab","doi":"10.1007/s10123-026-00815-2","DOIUrl":"10.1007/s10123-026-00815-2","url":null,"abstract":"<p><p>The current work aimed to formulate Rosemary essential oil nanoparticles (Ros-ES-NPs) and evaluate their antimicrobial effect in comparison with free oil (Ros- ES). Physicochemical characterization was performed using Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering, zeta potential analysis, transmission electron microscop y (TEM), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The cytotoxic activity of Ros-ES-NPs on human lung fibroblast cell line (Wi-38) was examined in comparison with Ros- ES using MTT assay. Ros-ES exhibited dose-dependent cytotoxicity, with an IC₅₀ of approximately 6.06 mg/ml on Wi-38. In contrast, the Ros-ES-NPs not only showed no toxicity but actually appeared to increase cell viability (up to ≈ 136%) possibly due to high metabolic actvity.The antimicrobial activity of Ros-ES and Ros-ES-NPs was evaluated against three isolates of Multidrug-Resistant Bacteria, comprising two Gram-negative isolates (Shigella flexneri and Klebsiella pneumoniae) and one Gram-positive isolate (Streptococcus pneumoniae), alongside Candida albicans as the fungal pathogen. Ros-ES-NPs showed a significant antimicrobial efficacy against all isolates under study where, at 25 mg/ml, Ros-ES inhibited K. pneumoniae and Shigella flexneri by 55.16 ± 0.09% and 76.47 ± 1.16%, respectively, whereas Ros-ES-NPs showed inhibition rates of 95.66 ± 9.74% and 87.13 ± 2.63%, respectively. Against Streptococcus pneumoniae, at 25 mg/ml, Ros-ES inhibited by 68.75 ± 0.60%, while Ros-ES-NPs exhibited a higher inhibition rate of 80.73 ± 5.6%. In case of C. albicans, Ros-Es showed a higher inhibition (81.85 ± 0.54) than Ros-Es-NPs (60.39 ± 5.69). Rosemary essential oil nano-formulation significantly enhances antibacterial efficacy while improving biocompatibility and inducing pronounced microbial DNA damage.</p>","PeriodicalId":14318,"journal":{"name":"International Microbiology","volume":" ","pages":"1149-1159"},"PeriodicalIF":2.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13653882/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147929564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated transcriptomic and metabolomic analysis reveals the regulatory networks in response to heat stress in Pleurotus pulmonarius.","authors":"Na Lu, Guanping Chen, Hailong Wei, Jiayao Lin, Weike Wang","doi":"10.1007/s10123-026-00852-x","DOIUrl":"10.1007/s10123-026-00852-x","url":null,"abstract":"<p><p>An integrated transcriptomic and metabolomic analysis was conducted to elucidate the molecular mechanisms underlying heat stress response in Pleurotus pulmonarius, a commercially important edible mushroom sensitive to elevated temperatures. Through comparative RNA-seq and UPLC-MS based metabolomics, we identified 4,388 differentially expressed genes (DEGs) and 1,282 differentially accumulated metabolites (DAMs) in mycelia exposed to 42 °C for 6 h compared with control conditions. Integrated pathway analysis revealed that pyrimidine metabolism, tryptophan metabolism, and cysteine/methionine metabolism were coordinately reprogrammed at both transcriptional and metabolic levels, forming a synergistic regulatory network. These pathways collectively provide essential precursors for nucleic acid synthesis, modulate auxin (IAA)-mediated stress signaling, and sustain antioxidant capacity, respectively. Our findings establish a systems-level framework for understanding heat adaptation in P. pulmonarius and highlight key metabolic nodes that may serve as targets for molecular breeding of thermotolerant cultivars.</p>","PeriodicalId":14318,"journal":{"name":"International Microbiology","volume":" ","pages":"1345-1356"},"PeriodicalIF":2.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13653963/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148301740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel Aureobasidium pullulans isolate for the biological control of Penicillium commune in potato decay and its optimization for enhanced antifungal activity using the Taguchi method.","authors":"Noushin Shafiee, Keivan Beheshti-Maal, Hamid Reza Akkafi, Hashem Nayeri","doi":"10.1007/s10123-026-00863-8","DOIUrl":"10.1007/s10123-026-00863-8","url":null,"abstract":"<p><p>Penicillium commune is a significant postharvest fungal pathogen responsible for blue mold rot in stored potatoes, resulting in substantial economic losses worldwide. In this study, we isolated and characterized a novel epiphytic strain of Aureobasidium pullulans SBAN-IAUF-1 from potato foliage and evaluated its antagonistic activity against Penicillium commune SBAN-IAUF-12. The new isolate exhibited strong inhibitory effects, reducing pathogen growth by 60% in vitro and 69.41% in vivo, outperforming values reported for most previously studied A. pullulans strains. Extracellular antifungal metabolites produced by Aureobasidium pullulans SBAN-IAUF-1 also showed substantial antifungal activity, indicating that extracellular antifungal metabolites play a key role in antagonism. To further enhance extracellular antifungal metabolites activity, we applied a Taguchi L9 orthogonal design, which identified optimal culture conditions and significantly increased the extracellular antifungal metabolites activity. The optimal conditions suggested by L9 analysis for maximizing extracellular antifungal metabolites production were 20 °C, 7 days of incubation, pH 5, and 1% (wv^- 1) YMB concentration. This study provides the first report of a potato-derived A. pullulans isolate optimized through Taguchi methodology for controlling Penicillium commune. The strong biocontrol activity of Aureobasidium pullulans SBAN-IAUF-1 highlights its potential as an environmentally safe and effective candidate for postharvest management of blue mold disease in potatoes.</p>","PeriodicalId":14318,"journal":{"name":"International Microbiology","volume":" ","pages":"1509-1520"},"PeriodicalIF":2.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13653843/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148470461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic and antibiofilm activity of colistin combined with cinnamaldehyde and eugenol against colistin-resistant Acinetobacter baumannii clinical isolates.","authors":"Abdulhamit Çalı, Rukiye Aslan, Kübra Fırtına Topcu, Cem Çelik","doi":"10.1007/s10123-026-00848-7","DOIUrl":"10.1007/s10123-026-00848-7","url":null,"abstract":"<p><strong>Objective: </strong>This study aimed to evaluate the effectiveness of combinations of colistin (COL) with cinnamaldehyde (CIN) or eugenol (EUG) against planktonic and biofilm forms of colistin-resistant clinical Acinetobacter baumannii isolates.</p><p><strong>Methods: </strong>Minimum inhibitory concentration (MIC) values of COL and essential oil components in 10 colistin-resistant clinical isolates were evaluated by the broth microdilution method. Interactions were classified by the fractional inhibitory concentration index (ΣFICI) using the checkerboard method. Biofilm formation was detected using the crystal violet method and the inhibitory effects of selected combination ratios on biofilm formation were evaluated in isolates showing synergy. In addition, the time-dependent effects of synergy combinations on 48-h pre-formed biofilm biomass were examined.</p><p><strong>Results: </strong>Median MIC values of COL, CIN, and EUG were 8 (4-32), 128 (128-128), and 512 (256-1024) µg/mL, respectively. In combination, the MIC of COL decreased to 1 (0.5-16) µg/mL with CIN and to 2 (0.5-8) µg/mL with EUG (p = 0.002). Synergy was observed in half of the isolates in both combinations (median ΣFICI: 0.532 and 0.469). Three isolates formed strong biofilms and seven formed moderate biofilms. Biofilm inhibition ranged from 1.1% to 50.5% for COL-CIN combination and from 11.7% to 80.0% for the COL-EUG combination. In 48-h pre-formed biofilms, the residual biomass at 24 h was significantly lower than that at 1 h for both combinations (p < 0.05).</p><p><strong>Conclusions: </strong>COL-CIN and COL-EUG combinations reduced MICs in colistin-resistant A. baumannii and decreased both biofilm formation and 48-h pre-formed biofilm biomass. These findings are promising for combination-based antibiofilm strategies.</p>","PeriodicalId":14318,"journal":{"name":"International Microbiology","volume":" ","pages":"1319-1328"},"PeriodicalIF":2.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13653846/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148217705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antimicrobial synergism of silver and zinc oxide nanoparticles with antibiotics against clinical isolate of Cutibacterium acnes.","authors":"Hafez Al-Momani, Abdallah Albalwi, Ayman Alsheikh, Hadeel Albalawi, Iman Aolymat, Ashraf I Khasawneh, Hala Tabl, Ola Ebbeni, AbdelRahman M Zueter","doi":"10.1007/s10123-026-00849-6","DOIUrl":"10.1007/s10123-026-00849-6","url":null,"abstract":"<p><strong>Background: </strong>The need to develop alternative treatment approaches to acne vulgaris and other skin infections is becoming increasingly urgent due to the rising prevalence of antibiotic resistance in Cutibacterium acnes (a key pathogen related to such conditions). Nanoparticles (NPs) have shown great potential as antimicrobial agents that could improve the effectiveness of traditional antibiotics when administered together. This research examines antibacterial activity of silver NPs (Ag-NPs) and zinc oxide NPs (ZnO-NPs), both independently and when used collaboratively with common anti-acne antibiotics used to treat C. acnes.</p><p><strong>Methods: </strong>Ag-NPs and ZnO-NPs were biosynthesized using aqueous Peganum harmala extract as a reducing and stabilizing agent. The synthesized nanoparticles were characterized using UV-Vis spectroscopy, X-ray diffraction (XRD), scanning/transmission electron microscopy (SEM/TEM), and dynamic light scattering (DLS). This research examined two C. acnes clinical isolates (P1 and P2) and one reference strain (NCTC747) were used in this research. Broth microdilution assays were employed to determine minimum inhibitory concentrations (MICs). Checkerboard assays and fractional inhibitory concentration index (FICI) analysis were performed to explore synergy between antibiotics and NPs.</p><p><strong>Results: </strong>A successful formation of spherical Ag-NPs and hexagonal ZnO-NPs has been confirmed, with average crystallite sizes of approximately 13-14 nm and 53-55 nm, respectively. Both Ag-NPs and ZnO-NPs were found to exhibit strong antibiotic activity. The MICs of the tested antibiotics were significantly reduced when used in combination with AgNPs. The reduction was up to 2-8 fold compared to antibiotic monotherapy. Moreover, most Antibiotic-Ag-NPs combinations exhibited synergistic interactions in the FICI analysis (FICI ≤ 0.5). Meanwhile, there are increased moderate effects resulted from the ZnO-NP combinations. The Antibiotic MIC generally values reduced two-to-four-fold. The relevant FICI values suggested that the interactions were primarily additive (FICI ≈ 0.75), although there was some evidence of strain-dependent variations. A two-way ANOVA test showed that the MIC values reductions for both antibiotics and nanoparticles were statistically significant (p < 0.001).</p><p><strong>Conclusion: </strong>The potential of biosynthesized NPs as adjunct therapeutic agents for the management of acne-associated infections was suggested by their promising antibacterial and antibiotic-enhancing effects against C acnes.</p>","PeriodicalId":14318,"journal":{"name":"International Microbiology","volume":" ","pages":"1279-1297"},"PeriodicalIF":2.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13653834/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148175965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heterologous expression and characterization of a thermostable MprT metalloprotease from thermophilic Bacillus subtilis BSP in dual host systems.","authors":"Tanveer Majeed, Tawaf Ali Shah, Hina Jabeen, Mutwakel Dabiellil, Fatmah M Alqahtani","doi":"10.1007/s10123-026-00850-z","DOIUrl":"10.1007/s10123-026-00850-z","url":null,"abstract":"<p><p>Thermophilic bacteria represent a valuable source of robust enzymes for industrial applications, yet their high growth temperatures often limit large-scale cultivation. In this study, the MprT gene encoding a thermostable metalloprotease was cloned from the thermophilic Bacillus subtilis BSP and heterologously expressed in both Escherichia coli BL21(DE3) and the protease-deficient B. subtilis 1A751. The full-length MprT open reading frame (1638 bp), including its native signal and pro-peptide sequences, was amplified by PCR and inserted into the pET29b vector under the control of the T7 promoter for expression in E. coli. The same gene was subsequently cloned into the integration vectors pDR111 (IPTG-inducible hyper-spank promoter) and pSG1154 (xylose-inducible promoter) for chromosomal integration and extracellular secretion in B. subtilis 1A751. Recombinant constructs were verified by restriction digestion, Sanger sequencing, and SDS-PAGE, which confirmed production of a 36 kDa polypeptide. Functional expression was demonstrated on casein-supplemented agar plates containing appropriate inducers, with clear hydrolytic halos appearing after incubation at 60 °C. The purified recombinant MprT protease displayed optimal activity at 50 °C and pH 7-8, retained 82% of its initial activity after 30 min at 60 °C, and remained stable across a broad pH range (4-11). Activity was strongly stimulated by Ca²⁺, Fe²⁺, and Mn²⁺ ions and was completely abolished by EDTA, consistent with its classification as a metalloprotease. Compared with previous reports on thermolysin-like proteases, this work provides the first successful functional overexpression of the BSP-derived MprT gene in a protease-deficient B. subtilis host, enabling efficient extracellular production at moderate cultivation temperatures while preserving the enzyme's native thermostability and alkaline tolerance. These properties position the recombinant MprT as a promising candidate for detergent formulations and waste-to-biofuel processes conducted under harsh industrial conditions.</p>","PeriodicalId":14318,"journal":{"name":"International Microbiology","volume":" ","pages":"1267-1278"},"PeriodicalIF":2.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13653890/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148163190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Eco-phylogenetic diversity and relative pigment production in environmental Talaromyces purpurogenus isolates.","authors":"Youssuf Gherbawy, Amera Alqahtani, Hanan Alomari, Kholoud Alzahrani, Pet Ioan, Helal Al-Harthi","doi":"10.1007/s10123-026-00847-8","DOIUrl":"10.1007/s10123-026-00847-8","url":null,"abstract":"<p><p>Talaromyces purpurogenus is a filamentous fungus capable of producing red polyketide-like pigments with potential as natural alternatives to synthetic colorants. This study investigated the ecological distribution, phylogenetic diversity, and relative pigment-producing capacity of T. purpurogenus isolates recovered from agricultural soils, decaying fruits, spoiled grains/cereals, and stored feed/food materials. A total of 35 isolates were obtained, with the highest isolation frequencies observed in agricultural soils and spoiled grains/cereals. Molecular identification based on ITS rDNA and β-tubulin sequence similarity supported the assignment of the isolates to T. purpurogenus. Multilocus phylogenetic analysis revealed well-supported intraspecific subclades, suggesting notable genetic diversity among the examined isolates. Pigment production, semi-quantitatively evaluated spectrophotometrically at 500 nm (OD₅₀₀) following ethyl acetate extraction, varied significantly among isolates. Statistical analysis demonstrated a significant association between phylogenetic clustering and relative pigment production (p < 0.001), as well as between ecological origin and pigment production levels (p < 0.01), indicating that pigment-associated phenotypes are influenced by both genetic background and environmental factors. Strain PP05 exhibited the highest relative pigment production and was selected for optimization studies. Experimental analysis showed that pH, temperature, carbon and nitrogen sources, and incubation period significantly affected pigment production (p < 0.001), with maximum relative pigment production recorded at pH 5.0 and 24 °C in sucrose-peptone medium after 7 days. These findings provide an eco-phylogenetic perspective on pigment-associated variability in T. purpurogenus and highlight its relevance for future strain-selection and biotechnological studies.</p>","PeriodicalId":14318,"journal":{"name":"International Microbiology","volume":" ","pages":"1465-1476"},"PeriodicalIF":2.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13653876/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148387649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Copper homeostasis networks in pseudomonas aeruginosa and the organocopper metabolite fluopsin C.","authors":"Dongwon Choi, Tariqul Islam","doi":"10.1007/s10123-026-00837-w","DOIUrl":"10.1007/s10123-026-00837-w","url":null,"abstract":"<p><p>Copper is an essential redox-active trace element that serves as a catalytic cofactor in many bacterial enzymes; however, excess intracellular copper is highly cytotoxic due to mismetallation of metalloproteins and copper-driven redox cycling that promotes reactive oxygen species generation through Fenton-like chemistry. To prevent these destructive effects, bacteria maintain near-zero levels of free cytosolic copper through tightly coordinated copper homeostasis networks. This review summarizes current understanding of bacterial copper stress physiology with a focus on the exceptionally copper-tolerant opportunistic pathogen Pseudomonas aeruginosa. This organism deploys a multilayered detoxification strategy that includes periplasmic copper surveillance and export mediated by the CopRS-PcoBA system, as well as highly sensitive cytoplasmic copper sensing that activates CueR-regulated efflux modules. A distinctive feature of the P. aeruginosa copper homeostasis network is the biosynthesis of the organometallic copper complex fluopsin C via a copper-responsive biosynthetic operon and its subsequent export through a dedicated efflux pump. This pathway supports a model in which fluopsin C functions as a copper-sequestering metabolite that stabilizes Cu(I), suppresses redox-mediated toxicity, and enables safe copper removal as a ligand-bound complex. Beyond its physiological role in copper detoxification, fluopsin C exhibits broad-spectrum antibacterial and antifungal activity and pronounced cytotoxicity toward mammalian tumor cell lines, consistent with a mechanism involving membrane disruption and ionophore-like copper shuttling. These properties suggest potential utility of fluopsin C as a metal-based, membrane-active antimicrobial in localized or formulation-controlled applications. Despite renewed interest in fluopsin C, optimization of its production remains limited, underscoring the need for future cultivation and bioprocess studies to improve yield and enable broader experimental and translational evaluation.</p>","PeriodicalId":14318,"journal":{"name":"International Microbiology","volume":" ","pages":"1091-1105"},"PeriodicalIF":2.9,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13653836/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147837732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}