Mei Cao

Microbial degradation of cable insulation materials is a critical issue affecting the reliability of power systems. In this study, metagenomic analysis was employed to reveal the microbial community structure on contaminated substation cables, identifying Curvularia lunata as a dominant fungal species in high-voltage environments. Subsequently, a specific strain, Curvularia lunata B3 , was isolated and identified for further investigation. To assess its specific impact on insulation performance, artificial inoculation experiments were conducted on secondary cable samples. Multi-dimensional characterization techniques, including SEM, WCA measurements, halogen moisture analysis, FTIR, XPS, and LCR digital bridge testing, were utilized to evaluate material degradation. The results demonstrated that C. lunata colonization caused significant surface erosion, characterized by the formation of holes and furrows. This physical damage was accompanied by a marked decrease in hydrophobicity, with the water contact angle dropping from 88.30 ± 0.79° to 78.27 ± 1.27°, and a gradual increase in water content to approximately 1.2% over 60 days. Chemical analysis revealed that microbial activity induced oxidation and dechlorination of the PVC insulation, evidenced by the reduction of C-Cl bonds and the emergence of oxygen-containing functional groups. These physicochemical alterations significantly compromised the electrical insulation of the cables, as evidenced by a marked decrease in series resistance (Rs) and an increase in series capacitance (Cs). This study elucidates the mechanisms of fungal erosion on cable insulation and provides a scientific basis for developing targeted protective strategies in power systems.

Introduction: The growing prevalence of drug-resistant pathogens urgently calls for new treatment strategies. Traditional Chinese medicine (TCM) formulas, with their multi-targeted mechanisms of action, offer promising alternative options for antimicrobial therapy. This study aims to evaluate the antimicrobial activity of the TCM formula MangHuang solution (MH) after content detection of tannin, composed of Rhei Radix et Rhizoma, Natrii Sulfas , and Galla Chinensis , and to elucidate its antifungal mechanism against Candida albicans through integrated multi-omics analysis. Methods: MH and its individual or combined components were prepared and evaluated for their inhibitory effects on Staphylococcus aureus, Escherichia coli , and Candida albicans , and their antimicrobial activity was assessed. Transmission electron microscopy (TEM), biofilm formation experiments, and multi-omics analysis were used to investigate the antifungal mechanism of MH against C. albicans . Results: MH demonstrated potent and rapid antibacterial activity. Biofilm formation was significantly inhibited, manifested by reduced cell surface hydrophobicity, weakened initial adhesion capacity, and impaired biofilm maturation processes. Transcriptome and metabolome analyses revealed significant alterations in key metabolic pathways, particularly ABC transporters, amino acid biosynthesis, and protein-related pathways. Discussion: MH exhibits potent antifungal activity against C. albicans through a multi-target mechanism, primarily affecting biofilm formation and intracellular metabolic processes. The integration of multi-omics approaches provides strong evidence for the potential clinical application of MH as an effective antifungal agent.

Helicobacter pylori (H. pylori) is the primary etiological agent for chronic gastritis, peptic ulcers, and gastric adenocarcinoma. The alarming rise in multidrug-resistant (MDR) strains, particularly against clarithromycin (CLR), metronidazole (MNZ), and levofloxacin (LVX), has severely compromised standard therapies. Thus, there is an urgent clinical need for novel antimicrobial agents that operate through distinct mechanisms to bypass resistance pathways and mitigate gastric cancer risk. We designed and synthesized a series of antimicrobial peptides, focusing on the proteolytically stable all-D-amino acid enantiomer, DT7-3, derived from a probiotic-sourced template. Minimum inhibitory concentrations (MICs) were determined against standard strains and 11 clinical MDR isolates via the broth microdilution method. Antimicrobial mechanisms were elucidated using scanning electron microscopy (SEM) for morphology, fluorescence-based assays for anti-adhesion activity, and real-time qPCR to quantify virulence gene expression (babA, ureA, and vacA). Biocompatibility was assessed using defibrinated sheep erythrocytes, gastric epithelial cells (GES-1), and representative beneficial gut microbiota. Analysis of the clinical isolates revealed resistance rates of 63.6% for CLR/LVX and 81.8% for MNZ, with 54.5% identified as MDR. DT7-3 exhibited superior potency (MIC 1–32 µg/mL) against all strains, significantly outperforming its L-enantiomer counterparts. Mechanistic studies unveiled a “triple-hit” mechanism: (1) rapid membrane disruption; (2) potent inhibition of bacterial adhesion to host cells (~60% reduction at 0.5 × MIC); (3) significant downregulation of critical virulence factors (babA, ureA, and vacA). Furthermore, DT7-3 showed an excellent safety profile, with negligible hemolysis ( 32 relative to mammalian cells. Crucially, DT7-3 showed high selectivity for the pathogen over beneficial gut microbiota (MIC > 128 µg/mL, SI > 16). Crucially, DT7-3 maintained potent bactericidal activity (MIC ≤ 16 µg/mL) even under cholesterol-enriched conditions. The engineered D-peptide DT7-3 is a potent candidate for combating MDR H. pylori. Its multifaceted mechanism, targeting bacterial viability while suppressing core virulence factors, positions it as a robust lead compound for next-generation eradication therapies aimed at reducing the burden of H. pylori-associated diseases.

With the widespread use of ionizing radiation (IR) in medical and industrial settings, irradiation has become increasingly common, posing significant risks to human health. Among the various organs affected, the gut is particularly sensitive to radiation-induced damage, leading to conditions such as radiation-induced intestinal damage (RIID). Recent studies have emphasized the critical role of gut microbiota and its metabolites in mitigating radiation-induced injury. This review discusses the effects of IR on the mammalian and human gut microbiota. We examine the dynamics of gut microbiota composition during and after irradiation, and emphasize the protective role of the gut flora and the metabolites in the pathophysiological mechanisms exhibited during radiation injury. In addition, this article investigates how specific metabolites, such as short-chain fatty acids and indole derivatives, may contribute to the mitigation of inflammation and promotion of gut barrier integrity. In addition, various therapeutic strategies based on modulating the gut microbiota, such as probiotics, antibiotics, and fecal microbiota transplantation, are discussed to understand their potential to prevent or mitigate RIID. Understanding the interactions between IR, gut microbiota and their metabolites provides new avenues for developing innovative therapeutic approaches to improve patient outcomes during and after radiotherapy. Future research directions could focus on optimizing microbiota-based therapies and exploring the role of diet and lifestyle in enhancing intestinal health during irradiation.

Ganoderma species are widely distributed in the world with high diversity. Some species are considered to be pathogenic fungi while others are used as traditional medicine in Asia. In this study, we sequenced and assembled four Ganoderma complete mitogenomes, including G. subamboinense s118, G. lucidum s37, G. lingzhi s62, and G. lingzhi s74. The sizes of the four mitogenomes ranged from 50,603 to 73,416 bp. All Ganoderma specimens had a full set of core protein-coding genes (PCGs), and the rps3 gene of Ganoderma species was detected to be under positive or relaxed selection. We found that the non-conserved PCGs, which encode RNA polymerases, DNA polymerases, homing endonucleases, and unknown functional proteins, are dynamic within and between Ganoderma species. Introns were thought to be the main contributing factor in Ganoderma mitogenome size variation (p < 0.01). Frequent intron loss/gain events were detected within and between Ganoderma species. The mitogenome of G. lucidum s26 gained intron P637 in the cox3 gene compared with the other two G. lucidum mitogenomes. In addition, some rare introns in Ganoderma were detected in distinct Basidiomycetes, indicating potential gene transfer events. Comparative mitogenomic analysis revealed that gene arrangements also varied within and between Ganoderma mitogenomes. Using maximum likelihood and Bayesian inference methods with a combined mitochondrial gene dataset, phylogenetic analyses generated identical, well-supported tree topologies for 71 Agaricomycetes species. This study reveals intraspecific and interspecific variations of the Ganoderma mitogenomes, which promotes the understanding of the origin, evolution, and genetic diversity of Ganoderma species.

In the present study, two mitogenomes from theFilobasidiumgenus were assembled and compared with otherTremellomycetesmitogenomes. The mitogenomes ofF. wieringaeandF. globisporumboth comprised circular DNA molecules, with sizes of 27,861 bp and 71,783 bp, respectively. Comparative mitogenomic analysis revealed that the genetic contents, tRNAs, and codon usages of the twoFilobasidiumspecies differed greatly. The sizes of the twoFilobasidiummitogenomes varied greatly with the introns being the main factor contributing to mitogenome expansion inF. globisporum. Positive selection was observed in several protein-coding genes (PCGs) in theAgaricomycotina, Pucciniomycotina, andUstilaginomycotinaspecies, includingcob,cox2,nad2, andrps3genes. Frequent intron loss/gain events were detected to have occurred during the evolution of theTremellomycetesmitogenomes, and the mitogenomes of 17 species fromAgaricomycotina,Pucciniomycotina, andUstilaginomycotinahave undergone large-scale gene rearrangements. Phylogenetic analyses based on Bayesian inference and the maximum likelihood methods using a combined mitochondrial gene set generated identical and well-supported phylogenetic trees, whereinFilobasidiumspecies had close relationships withTrichosporonalesspecies. This study, which is the first report on mitogenomes from the orderFilobasidiales, provides a basis for understanding the genomics, evolution, and taxonomy of this important fungal group.