Archives of Microbiology最新文献

Fungal infections, particularly those caused by dermatophytes, affect over 25% of the world's population and pose a significant public health risk to both humans and animals. Conventional antifungal treatments face substantial challenges like drug resistance, adverse effects, and require long-term systemic medications. Essential oils (EOs) have attracted attention for their antimicrobial properties; however, their therapeutic applications have been hampered by their low solubility and rapid degradation. Nanotechnology addresses these limitations by encapsulating EOs to enhance their durability, bioavailability, and antifungal properties. This review covers the potential EO-based nanoformulations for treating fungal infections, with a focus on dermatophytes. It also highlights how nanoencapsulation may help reduce drug resistance, toxicity, and adverse effects. However, there are some limitations. The effectiveness of treating fungal infection can vary depending on the EO's composition, fungal species, and how the nanoformulation is formulated. Future research should emphasize standardizing formulation protocol and evaluating in vivo efficacy and safety through well-designed clinical trials. While EOs represent a promising approach, they are not a substitute for evidence-based antifungal treatment and must not be used without medical guidance.

The human gut microbiome harbors diverse beneficial bacteria with potential roles in supporting host health. Parabacteroides distasonis has recently attracted interest as a next-generation probiotic (NGP) candidate; however, functional evidence for human-derived strains remains limited. Here, three human gut-derived P. distasonis strains (B2-S-102, B2-Q-110, and Y3-G-102) were isolated from healthy individuals and characterized using comparative genomics and in vitro functional assays. Species-level identity was supported by 16S rRNA gene analysis and whole-genome relatedness metrics (ANI > 97% and dDDH > 70%), consistent with established species delineation thresholds. Under controlled laboratory conditions, the strains showed tolerance to acidic pH (pH 2.0), bile salts (0.3%), and simulated gastric and intestinal fluids. Functionally, the strains exhibited measurable antioxidant activity (35.03 ± 7.76% to 51.22 ± 5.60% DPPH inhibition) and α-amylase inhibitory activity (51.03 ± 32.12% to 69.23 ± 4.26%) in vitro. Cell-free supernatants inhibited albumin denaturation (47.65 ± 3.56% to 65.26 ± 4.15%), while live bacteria reduced nitric oxide production and pro-inflammatory cytokines (IL-6, TNF-α, IFN-γ, and IL-1β) in LPS-stimulated RAW 264.7 macrophages (p < 0.05). The strains also displayed in vitro growth-inhibitory activity against Escherichia coli, Acinetobacter baumannii, and Salmonella enteritidis. Genome mining identified multiple biosynthetic gene clusters, indicating genetic potential for secondary metabolite production; however, expression and metabolite identity were not experimentally validated. No haemolytic activity was observed, supporting a favorable preliminary safety profile. Overall, these findings provide preliminary in vitro evidence supporting the potential of human-derived P. distasonis strains as NGP candidates for further evaluation.

The global production of Penaeus vannamei shrimp is threatened by Vibrio parahaemolyticus, a pathogen causing severe disease outbreaks and economic losses, especially in Asia. This study developed and characterized stable sunflower oil-based nanoemulsions (NEs) and incorporated them into formulated feed for targeted antimicrobial control. Physicochemical analyses (particle size, zeta potential, viscosity, stability) confirmed uniform formulations. Antimicrobial efficacy was evaluated using MIC/MBC, adherence, biofilm inhibition, oxygen consumption rate (OCR), and virulence gene expression assays. NE-23 and NE-27 showed strong antibacterial activity (MIC/MBC: 1-256/2-170 µg/mL), consistent with gentamicin. NE-22 exhibited the highest anti-adherence activity (70.62%), while NE-23 and NE-21 were most effective against pathogenic strains. Biofilm inhibition reached 72.17% (NE-22, MTCC-451) and 59-60% (NE-23, shrimp isolates), comparable to gentamicin. Dead cell assays revealed NE-24 induced up to 68.52% mortality, surpassing gentamicin in some strains. OCR analysis showed greater inhibition by NE-22 (0.31-fold reduction) than gentamicin (0.66-fold). Gene expression profiling demonstrated relative downregulation by NE-23. Finally, nanoemulsion-infused formulated feed conferred in vivo protection against V. parahaemolyticus without affecting shrimp growth or survival. Overall, NE-22 and NE-23 emerged as potent antibiotic alternatives, offering a sustainable strategy to mitigate V. parahaemolyticus infections in shrimp aquaculture.

This study presents the first integrated analysis of cyanobacterial and microalgal diversity in soils and biological soil crusts from the sand dunes of the Russian High North, combining morphological characterization with DNA barcoding of cultured isolates. We identified 33 taxa across four phyla, dominated by Chlorophyta (Trebouxiophyceae and Chlorophyceae). Although ITS2 sequencing is widely used for phylogenetic studies, only approximately 35% of eukaryotic algal strains in our study could be confidently identified to the species level, underscoring both the limitations of this marker for certain taxonomic groups and the ongoing challenges in algal systematics. ITS2 sequencing limitations as a single-locus marker were revealed when analyzing phylogenetically complex genera, including Asterochloris, Klebsormidium, Interfilum, and Vischeria, where robust classification required integration of additional genetic markers. Phylogenies revealed taxonomic gaps in several algal lineages (Spongiococcum, Myrmecia, Leptosira, and the Radiococcaceae family), exacerbated by critical gaps in reference databases. We identified eight novel candidates via concordant molecular and morphological divergence, including one potential new genus. Ecological roles varied, ranging from free-living soil crust formers (Klebsormidium spp., Kalymmatonema sp.) to lichen symbionts (Asterochloris spp., Myrmecia israelensis). Remarkably, we documented the rare cyanobacterium Dapisostemon apicaliramis in these sand dunes, expanding its known range beyond Brazil. Our findings demonstrate the necessity of multi-locus approaches to resolve taxonomic uncertainties in understudied genera, while emphasizing the crucial role these microbial communities play in stabilizing fragile northern taiga ecosystems in Western Siberia.