Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology最新文献

Gastroenteritis is a prevalent digestive disorder that contributes to significant morbidity worldwide, often caused by pathogenic bacteria. Probiotics are increasingly recognized for their therapeutic potential in treating gastrointestinal diseases due to their beneficial effects on gut health. This study aimed to explore the antimicrobial, antioxidant, anti-diabetic, and anti-inflammatory properties of Enterococcus faecium metabolites, isolated from a milk sample, against Salmonella enterica. The bacterial strains were isolated using the streak plate method and molecularly characterized, with Enterococcus faecium showing 93.79% sequence similarity and Salmonella enterica showing 96.97% similarity in 16S rRNA sequencing. Metabolites of Enterococcus faecium were extracted using solvents such as ethanol, methanol, n-butanol, and ethyl acetate, resulting in 14 bioactive compounds, including lactic acid, acetic acid, and indole. Antimicrobial activity was evaluated via the disc diffusion method, revealing a dose-dependent increase in the zone of inhibition, reaching 20 mm at 100 µg/mL against Salmonella enterica. Antioxidant activity, assessed using the DPPH assay, exhibited a maximum scavenging rate of 99.8% at 550 µg/mL, while anti-diabetic activity showed 84.66% inhibition of alpha-amylase at 500 µg/mL. The anti-inflammatory activity demonstrated 99% inhibition of protein denaturation at the same concentration. No hemolytic activity was observed at lower concentrations, with the maximum hemolysis of 90% occurring at 250 µg/mL. In conclusion, Enterococcus faecium metabolites exhibited significant in vitro antimicrobial, antioxidant, anti-diabetic, and anti-inflammatory activities, indicating their promise as candidates for further investigation in the context of Salmonella enterica-induced gastroenteritis and related metabolic disorders. Future studies should focus on further clinical applications of these metabolites.

Sodium dodecyl sulfate (SDS), an anionic detergent found in cleaning products and cosmetics, is one of the chemical pollutants in waterways. SDS-utilizing bacteria were isolated from soil and water samples using 0.05% SDS basal medium. Three bacterial isolates were selected for 16S rRNA sequencing based on their ability to solubilize phosphate, potassium, and zinc, and they were identified as Pseudomonas putida MSK86 OR192890, Klebsiella pneumoniae NET12 OR345422, and Enterobacter sp. MSK86 OR398804. Enterobacter sp. MSK86 and K. pneumoniae NET12 lowered the SDS concentration in the sample 84.78% and 75.65%, respectively, while P. putida MSK86 reduced it 33.43% on the sixth day of incubation. A phosphate-potassium-zinc co-inoculum was prepared using Enterobacter and Pseudomonas species. Laundry wash water was added with the bacteria, individually and co-inoculum, and the fortified water was used to irrigate the Capsicum annuum L. seedlings. On the 45th day, the plants were harvested, and total glucose, protein, chlorophyll, and proline were checked by comparing control plants. Enterobacter sp. MSK86 increased carbohydrate and proline levels by 37.22 mg/g (± 0.54 SE) and 2.44 mg/g (± 0.1 SE), while K. pneumoniae NET12-treated plants showed an increase in chlorophyll by 1.95 mg/g (± 0.02 SE) and total protein by 1.94 mg/g (± 0.03 SE). The bacteria in this study showed they could lower SDS levels in graywater and improve farming by adding nutrients to the soil and plants, offering a sustainable way to tackle detergent pollution, fertilizer use, and water scarcity.

The Gram-negative bacterium Xanthomonas campestris pv. campestris is the etiological agent of black rot, a widespread and destructive disease affecting cruciferous plants. In this study, a lon mutant was obtained by EZ-Tn5 transposon mutagenesis of the X. campestris pv. campestris. The lon gene encodes an ATP-dependent protease implicated in protein quality control and stress adaptation across various bacterial species. Functional analysis revealed that lon disruption in X. campestris pv. campestris resulted in diminished extracellular protease activity, reduced virulence, and heightened sensitivity to puromycin and elevated temperatures. Complementation with the wild-type lon allele restored most phenotypes, except thermotolerance, which was only partially recovered. Interestingly, lon overexpression in wild-type cells compromised growth under heat stress, indicating that lon dosage is critical for thermal adaptation. Promoter activity assays indicated that lon expression is subject to catabolite repression and is induced by heat shock. Additionally, analysis of upstream regions of lon and multiple experimentally validated heat-inducible genes revealed a conserved motif similar to the σ³²-binding site in Escherichia coli, suggesting a conserved σ³²-mediated regulatory mechanism. This work provides the functional and regulatory characterization of lon in X. campestris pv. campestris, underscoring its integral role in stress resilience and pathogenicity.

Preen gland bacteria are thought to be the key producers of preen oil components such as chemosignalling molecules including volatile organic compounds (VOCs) and antimicrobial compounds including peptides and antimicrobial VOCs. However, data on the preen oil bacteriome and chemical composition are limited to a small subset of bird species, and the presence of antimicrobial peptides is largely unexplored. Here, we performed an exploratory study to characterize, for the first time, the preen oil chemical and proteomic profiles and to explore the possible contribution of the bacteriome to the production of preen oil VOCs and antimicrobial peptides (bacteriocins) in eight passerine species, each represented by a single individual. Preen oil bacteriome, chemical and proteomic profiles varied among birds. The bacterial profiles were dominated by the genera Streptococcus, Lactococcus, Corynebacterium and Cutibacterium. The chemical profiles mainly consisted of alcohols, ketones and carboxylic acids. The biological functions primarily associated with the proteomic profiles were proteolysis and response to oxidative stress. Although we were unable to explore a direct association between the bacteriome and chemical profiles, the preen oil contained bacteriocin- and VOC-producing bacterial genera capable of producing detected microbially-derived VOCs (mVOCs), the relative abundance of which varied between birds. Riparian species showed the highest chemical diversity and high abundances of putative preen oil mVOC-producing bacteria, which could suggest habitat-specific adaptations. This exploratory study may significantly contribute to the formulation of hypotheses on the potential role of host ecological factors in the variation of preen oil bacterial, chemical and proteomic profiles in passerines.

Pollution by aromatic hydrocarbon compounds is closely associated with oil industry activities and poses significant environmental and human health risks. Biodegradation using hydrocarbon-degrading bacteria, particularly in combination with dispersants, offers a promising approach to mitigate such pollution. In this study, phenanthrene was used as a model compound to evaluate the effect of dispersant addition on the degradation capacity of Bacillus subtilis strain CYA27. Two dispersants were compared: a palm oil-based dispersant (Bio-OSD) and a petroleum-based dispersant (Non-Bio-OSD). The results showed that the presence of Bio-OSD and Non-Bio-OSD enhanced phenanthrene degradation, achieving up to 73.9% and 46.7% after 35 days, respectively. This improvement was attributed to increased substrate bioavailability, the potential use of dispersants as an auxiliary carbon source via a cometabolic mechanism, as supported by the detection of catechol dioxygenase activities (C12O and C23O) and selected metabolic intermediates, which provide preliminary evidence for possible enzymatic involvement in aromatic ring cleavage. Metabolic profiling using LC–MS/MS revealed that the degradation pathways utilised in the presence of dispersants included both the salicylic acid and phthalic acid pathways, which are further metabolised through the tricarboxylic acid (TCA) cycle. In contrast, phenanthrene biodegradation proceeded without a dispersant via the formation of 4-methoxy-1-naphthol, suggesting a methoxylation mechanism that potentially reduces toxicity but does not proceed to the TCA cycle. These findings revealed that dispersants not only enhance substrate bioavailability but also alter bacterial metabolic preferences, highlighting their dual role in oil spill bioremediation strategies. This work provides novel insight into phenanthrene catabolism and the mechanistic effects of dispersants on marine PAH biodegradation.

Continuous cropping obstacle from Chinese yam (Dioscorea spp.) is widespread in China, and it seriously reduced the yield and quality. Rhizosphere soil microbiome is rich and associated with continuous cropping obstacle. However, the effect of long-term consecutive monoculture (LTCM) of Chinese yam on rhizosphere soil fungal community is still limited. In this study, fields that were consecutively cropped with Chinese yam for 1, 10 and 20 years were subjected to rhizosphere soil fungal analysis. High-throughput sequencing was used to characterize rhizosphere soil fungal community structure and function, and to determine the effect of long-term consecutive monoculture (LTCM). Results indicated that LTCM induced soil acidification, increased concentration of soil available potassium (AK) and available phosphorus (AP), increased the richness but decreased the evenness of fungal community. However, the Shannon index in YF_10Y fungal community showed the lowest value. Increasing years of monoculture resulted in significant differentiation in community composition, marked by a reduction of biocontrol fungi and an increase of pathogens. Additionally, consecutive monoculture decreased the rate of carbohydrate and amino acid degradation. The comprehensive analysis conducted in this study provides insight into rhizosphere fungal structure and function in response to LTCM of Chinese yam. Information obtained in this study could be used for the development of new microbial fertilizers for Chinese yam, which would mitigate the problems associated with continuous monoculture.

Edible mushrooms face persistent challenges in yield optimization, bioactive compound production, and climate resilience that conventional breeding methods struggle to address. Traditional approaches such as cross-breeding, protoplast fusion, and mutagenesis are limited by genetic noise, laborious screening, and unstable trait inheritance. This review proposes a transformative paradigm built upon converging advances in molecular biology and data science: the bio-digital feedback loop (BDFL) framework, integrating multi-omics, CRISPR-engineered chassis strains, and predictive phenomics for precision mushroom breeding. Our framework employs multi-omics to decipher gene networks governing critical traits, such as substrate degradation enzymes, developmental synchrony regulators, and secondary metabolite pathways. CRISPR-Cas9 and synthetic biology tools then deploy these insights to verify and design modular gene circuits in pre-engineered "plug-and-play" chassis strains, enabling conflict-free stacking of desirable traits. Artificial intelligence serves as the linchpin, not only automating high-throughput phenotyping through advanced imaging but also accelerating the entire breeding cycle by predicting trait heritability from omics data and optimizing the design of CRISPR guide RNAs and genetic constructs for efficient editing. The BDFL we describe iteratively refines strains by feeding phenomics data back into AI algorithms, enabling rapid trait optimization cycles. This transcends the trial-and-error limitations of classical methods, accelerating development of climate-smart mushrooms for circular bioeconomies including strains engineered to thrive on agricultural waste, overproduce immunomodulatory compounds, or resist emerging pathogens. The integration of predictive genomics, AI-driven phenomics, and CRISPR-edited chassis strains heralds a new era of precision mycology, where mushrooms are computationally designed as sustainable solutions for global food security, pharmaceutical innovation, and ecological resilience, ultimately transforming fungi into programmable biological factories tailored to address pressing agricultural and ecological challenges.

The emergence of multidrug-resistant pathogens has increased the urgency for alternative treatment options for infections like cystitis. This study focused on the green synthesis of silver nanoparticles and cysteine-conjugated silver nanoparticles utilizing Melaleuca lanceolata leaf extract, optimized via artificial neural networks for controlled nanoparticle size. The ANN model provided precise prediction and control of nanoparticle size, reducing experimental variability. The characterization was performed using UV–Vis spectroscopy, which showed peaks at 445 nm for AgNPs and 405 nm for Cys-AgNPs. Additionally, FTIR, SEM, and EDX analysis confirmed the successful synthesis of AgNPs and their conjugation with cysteine. Biological analyses revealed that Cys-AgNPs had increased antioxidant and anti-inflammatory effects over AgNPs and controls. Notably, they demonstrated better antibacterial activity against Staphylococcus nepalensis, a new uropathogen causing cystitis, with a 17 mm inhibitory zone and a lowest inhibitory concentration of 25 µg/ml. Direct cytotoxicity assays and in vivo studies in animal models were not carried out, but the observed reduction in hemolysis in vitro demonstrates that it may be biocompatible. These results demonstrate the novelty of using ANN-based optimization and green nanotechnology to produce stable, functionalized nanoparticles of therapeutic interest. It is recommended that cytotoxicity analyses, in vivo confirmation, and wider MDR pathogen testing should be performed in the future to ensure clinical relevance.