AMB Express最新文献

Many studies focus on optimizing the dark fermentative biohydrogen production. In the present work, static magnetic field (SMF) S pole and N pole were applied to the dark fermentation system of Clostridium pasteurianum to evaluate the effect of magnetic field direction on biohydrogen production process of Clostridium pasteurianum. The experimental results showed that the magnetic S pole application was more effective than the magnetic N pole application in improving microbial hydrogen production progress parameters. The maximum hydrogen production 2.47 ± 0.010 mol H₂/mol glucose was achieved in the magnetic S pole application group. Meanwhile, the maximum biomass, carbon conversion efficiency and energy conversion efficiency in magnetic S pole application group were increased by 93%, 27.7% and 28.3%, respectively, compared with the control group. The results provided a new information for further exploring the application of magnetic field in dark fermentative biohydrogen production process.

This study explores the microbial-assisted synthesis of nanoparticles from chalcopyrite ore and its tailings, emphasizing their potential applications in sustainable agriculture. Addressing the gap between research and practical field applications, the study employs microbial diversity to recover valuable elements as nanoparticles through green methods. Organic acids and metabolites produced by microorganisms facilitated the breakdown of mineral ores into nanoparticles. Optimal conditions (28 °C, pH 3.8) yielded nanoparticles (15-200 nm) after 72 h, as analysed by Dynamic Light Scattering and Scanning Electron Microscopy. Glycine encapsulation was confirmed via UV spectroscopy. In vitro experiments on Cicer arietinum (L.) demonstrated enhanced plant growth, including increased seed germination, branching, and early flowering, highlighting the potential of these nanoparticles in agricultural enhancement.

Drug-resistant Pseudomonas aeruginosa poses a significant clinical challenge due to its intrinsic antibiotic resistance and the formation of metabolically dormant persister cells. Here, we evaluated the antibacterial and anti-persister activities of a novel 20-amino-acid cationic antimicrobial peptide (RRFFKKAAHVGKHVGKAARR) alone and in combination with silver nanoparticles (AgNPs) against P. aeruginosa PAO1. Minimum inhibitory concentrations (MICs) were determined by broth microdilution (128 µg/mL for the peptide; 8 µg/mL for AgNPs), and checkerboard assays revealed a strong synergistic interaction (fractional inhibitory concentration index (FICI) = 0.25). Treatment of colistin-induced persister populations with the peptide-AgNP combination reduced viable cells by 94.3 ± 2.1% (p < 0.01), markedly outperforming either agent alone. MTT assays in Caco-2 cells demonstrated > 85% viability at concentrations up to the MIC, indicating low host cytotoxicity. Mechanistic insights suggest that membrane disruption by the peptide, coupled with reactive oxygen species (ROS) generation and intracellular interference by AgNPs, underlies the enhanced eradication of both active and dormant bacterial cells. These findings support further in vivo investigation of AMP-AgNP co-therapy as a promising strategy to overcome antibiotic tolerance in P. aeruginosa.

The mechanisms driving age-related macular degeneration (AMD) progression into two major but distinct vision-threatening subtypes, geographic atrophy (GA) and choroidal neovascularization (CNV), are unclear. This study identifies causal gut microbiota (GM) taxa involved in AMD and their connections to biological aging phenotypes, including epigenetic clock acceleration, telomere length, mitochondrial DNA copy number, 731 immune cell traits, and 91 inflammatory proteins through genetic prediction. Analyzing 207 GM taxa and 205 functional pathways alongside AMD progression GWAS data, we found that class_Gammaproteobacteria significantly influences both CNV and GA, and a bidirectional gut-retina axis involving Erysipelotrichaceae was also identified. Genus_Flavonifractor, species_Ruminococcus_obeum, and species_Streptococcus_thermophilus may attenuate AMD progression. Mediation analysis revealed pathways linking Ruminococcus obeum to GA progression via SSC-A expression on CD4 + T cells, and a CNV-associated pathway mediated by CD33dim HLA-DR + CD11b- cell counts. This study provides novel genetic evidence linking GM to dynamic AMD progression, offering genetic insights for future experimental research and clinical strategies.

Aflatoxin contamination of milk is a serious health concern. When animals ingested food contaminated with aflatoxin B1 (AFB1), it would be converted into aflatoxin M1 (AFM1) and secreted in the milk. This carcinogenic and hepatotoxic toxin could be overcome by biological methods. Therefore, this study aimed to assess the anti-aflatoxigenic effect of the probiotic Lactobacillus rhamnosus (L. rhamnosus) ATCC 7469, as well as its synbiotic combination with chitosan ZnO nanocomposite using ELISA. This is carried out by measuring AFM1 concentration in 90 milk samples, including 73 raw and 27 powdered milk samples. The average AFM1 concentration was 11.22 ± 11.31 and 10.62 ± 8.08 µg/kg, which exceeded the international regulatory limits for raw and powdered milk, respectively. All milk samples were treated with L. rhamnosus ATCC 7469 and a synbiotic combination of chitosan/ZnO nanocomposite and L. rhamnosus ATCC 7469. The results showed that the probiotic L. rhamnosus ATCC 7469, and the synbiotic combination significantly reduced the AFM1 concentration in milk (p value ≤ 0.05). The used probiotic bacteria showed binding to AFM1 from 10 to 83.8%, while the binding range increased to 34-92% after treating milk with the synbiotic combination. In conclusion, the biological treatment of milk using the probiotic, L. rhamnosus ATCC 7469, alone or in combination with chitosan/ZnO nanocomposite, is an efficient method for reducing the AFM1 concentration in milk. This study highlights the use of both metal nanoparticles (as a prebiotic) and probiotics, forming a synbiotic approach to control milk contamination with aflatoxins in the laboratory.