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

This study aimed to analyze the dynamic changes in gut microbiota during high-fat diet (HFD)-induced obesity in mice, investigate the transmissibility of obesity-associated inflammation via fecal microbiota transplantation (FMT), and identify key bacterial genera linked to inflammation. In experiment 1, 8 control group mice and 12 obese group mice were fed a normal diet (ND) and a HFD, respectively, and fecal samples were collected from six mice in each group at weeks 4, 8, and 12. The results showed that long-term HFD (12 weeks) significantly reduced the diversity and richness of the gut microbiota (p < 0.05). HFD significantly affected the composition of the gut microbiota during the experimental period, with an increase in the relative abundance of harmful bacteria genera such as Escherichia-Shigella and Proteus (p < 0.05). In experiment 2, the transmissibility of obesity-associated inflammation was validated through a fecal FMT experiment. The results indicated that the intestinal microbiota of obese mice increased the inflammation level of recipient mice (p < 0.05), and the composition of the intestinal microbiota in the obese recipient group was significantly affected by that in the obese donor group. Furthermore, correlation analysis revealed that the relative abundances of Proteus and Escherichia-Shigella were positively correlated with the levels of inflammatory factors in the serum and ileal tissue (p < 0.05), suggesting that these two bacterial genera may serve as potential pro-inflammatory biomarkers. This study revealed the dynamic changes in the gut microbiota during HFD-induced obesity, confirmed the critical role of the gut microbiota in the transmission of inflammation, and provided a new theoretical basis for the intervention of obesity-related diseases.

This study investigates the microbial degradation of phenolic compounds using environmental bacterial isolates obtained from refinery wastewater and petroleum-contaminated soil. Phenolic pollutants are highly toxic and persistent, posing significant challenges for biological wastewater treatment systems. To address this issue, microorganisms were enriched under increasing phenolic loads using Bushnell Haas Yeast (BHY) medium supplemented with phenol and mixed phenolic derivatives as the sole carbon source. Through adaptive passaging, two phenol-tolerant isolates were obtained and identified by 16S rRNA sequencing as Microbacterium arabinogalactanolyticum (PKN7) and Brevundimonas diminuta (VGT4). Time-resolved HPLC analyses demonstrated that both isolates completely degraded phenol within 120 h in BHY medium containing 20 mg/L phenol and 30 mg/L mixed phenolic compounds. While the strains exhibited only partial degradation of chlorophenols and cresols, consortium experiments showed enhanced performance in the mixed culture: the mixed culture achieved complete degradation of 2,4-dinitrophenol within 12 h and complete phenol removal within 60 h, while removing 73-78% of the remaining phenolic derivatives. These results confirm that cooperative metabolic interactions substantially enhance degradation performance under mixed-pollutant conditions. Overall, this study identifies M. arabinogalactanolyticum and B. diminuta as promising non-model phenol degraders, particularly when applied as a defined microbial consortium. Their combined activity highlights the potential for bioaugmentation-based strategies in industrial wastewater treatment systems. Further pilot-scale studies using real refinery effluents are needed to evaluate long-term stability and field applicability.

Inflammatory bowel disease (IBD), comprising Ulcerative colitis (UC) and Crohn's disease (CD), is a chronic inflammatory disorder of the gastrointestinal tract (GIT) that occurs due to several factors, including, but not limited to, gut microbiota dysbiosis, immune dysregulation, and environmental factors. Despite significant advances in IBD pharmacotherapy, patients often experience treatment failures due to suboptimal treatment responses, frequent relapses, and are also susceptible to developing several adverse effects (AEs), highlighting the need for developing alternative therapies. A growing body of evidence necessitates the importance of maintaining gut microbiome homeostasis, which is commonly disrupted in IBD. Probiotics have emerged as promising adjunctive IBD therapies due to their capacity to modulate immune responses, restore gut microbial balance, and preserve mucosal barrier integrity. Multiple probiotic strains, including Escherichia coli (E. coli) Nissle 1917, Lacticaseibacillus rhamnosus GG, Bifidobacterium longum (B. longum), Saccharomyces cerevisiae var. boulardii (S. boulardii), and combination formulations, such as VSL#3 (Lactobacillus, Bifidobacterium, and Streptococcus thermophilus), have demonstrated superior efficacy in inducing and maintaining remission in comparison with placebo and comparable efficacy with conventional treatments, such as mesalazine. While the efficacy of probiotics has been demonstrated in UC through several clinical studies, evidence supporting their use in CD remains inconsistent, with studies yielding mixed or inconclusive results. This highlights the necessity for additional carefully designed, large-scale studies specifically targeting CD patients to better understand the therapeutic potential of probiotics in a broader context. Finally, emerging innovations in genetic engineering and clustered regularly interspaced short palindromic repeats/ CRISPR-associated protein 9 (CRISPR/Cas9) technology offer exciting prospects for the development of precision probiotics, which could possess both diagnostic and treatment benefits and further expand the clinical utility of probiotics in IBD treatment.

Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), play crucial roles in regulating the host's response to Staphylococcus aureus (S. aureus) infections. These ncRNAs are involved in various biological processes, including immune regulation, inflammation, tissue repair, and apoptosis, and their dysregulation often contributes to the severity of S. aureus-induced diseases. Recent studies have highlighted the significance of ncRNAs in controlling both innate and adaptive immune responses, as well as their potential as biomarkers for disease diagnosis and prognosis. Additionally, ncRNAs are emerging as promising therapeutic targets, especially in light of the growing prevalence of antibiotic-resistant strains such as methicillin-resistant S. aureus (MRSA). However, while ncRNAs show great promise in improving treatment outcomes, much remains to be understood about their exact mechanisms in S. aureus pathogenesis. Further research into ncRNA-based therapeutic strategies is crucial to developing novel approaches for combating S. aureus infections and addressing the challenges posed by antibiotic resistance. This review emphasizes the potential of ncRNAs in S. aureus infections and their application in future therapeutic interventions.

The fermentation temperature of sauce-flavored high-temperature Daqu can reach 65 °C, where microbial diversity and abundance are closely associated with liquor yield and quality. This study aimed to isolate thermotolerant yeast strains from sauce-flavored high-temperature Daqu and investigate their tolerance mechanisms and safety profiles. Using sauce-flavored Daqu as material, culturable methods were applied for yeast isolation and screening, followed by whole-genome sequencing analysis. The biological characteristics were examined, and gain an in-depth understanding of their high-temperature resistance mechanisms and characteristics. A thermotolerant yeast strain L253 was isolated and identified as Lodderomyces elongisporus, exhibiting maximum temperature tolerance at 55 °C with optimal growth at 45 °C, pH tolerance of 3-8, alcohol tolerance up to 6.8% (v/v), and sugar tolerance reaching 80% (w/v). Safety assessments demonstrated weak nitrate reductase activity, non-hemolytic properties, and negative indole test, confirming its safety. The genome (GenBank: PRJNA1185419) measured 16,118,111 bp with 37.3% G + C content, containing 5,102, 4,170, 3,390 and 5,380 annotated genes in eggNOG, GO, KEGG and NR databases respectively. Thermotolerance-related genes included HSFF, HSP70 and its interacting proteins (HSPBP1, HSPA5/BiP), and HSP90, while osmotolerance involved gpd and gpp genes. In this study, the phenotype and genotype of strain L253 were analyzed to increase the understanding of microbial functions in the high-temperature Daqu environment, and reveal the potential value of this strain in industrial fermentation.

Traditional spontaneously fermented fish products offer a unique blend of flavors, aroma, taste, and texture that have been an integral part of global gastronomy. These products also represent a rich niche of indigenous bacterial species and fermentation-derived functional metabolites. It is important to identify the core bacterial species and their role in the fermentation process and synthesis of functional metabolites. This study presents an integrative profiling of bacterial communities and functional metabolites in Napham, a traditional fermented fish paste widely consumed by the Bodo tribe of Northeast India. Using 16S rRNA gene sequencing coupled with untargeted GC-MS based metabolomics, we characterized the bacterial and metabolite compositions of Napham collected from different geographical locations of Assam. Our results revealed a core bacterial consortium dominated by S. saprophyticus, S. piscifermentans, S. debuckii and L. acidipiscis, which also showed a strong positive correlation with key functional metabolites, including essential amino acids, PUFA, MUFA, and SCFA. Notably, variations in bacterial community structure across the Napham samples were linked to differential metabolite profiles, highlighting the influence of region-specific bacterial diversity on fermentation outcomes. These findings would aid in the development of starter-culture assisted fermented fish product with optimal functional properties on human health and wellness.

The quest to fit all cellular beings in one picture frame as the universal Tree of Life (ToL) has always been a daunting task for evolutionary biologists. Over the decades, ToL has emerged from a dichotomous topology to its present form with three domains; bacteria, archaea and eukarya. But this phylogenetic placement is also questionable due to the miscellaneous nature of certain housekeeping genes, horizontal gene transfers (HGT), and also due to incomplete pathways of pathogenic organisms. Furthermore, the ambiguous nature of viruses has always puzzled researchers about their placement in ToL. Despite the multiple attempts, lack of common genes, and their coevolution with host systems, placement of viruses has always been controversial and has often yielded scattered phylogeny among themselves. Recent discoveries-especially of giant viruses sharing genes with cellular domains-offer fresh insights that support the inclusion of viruses in the ToL framework. By focusing on the RNA polymerase subunit β (RpoB) gene, a conserved marker across bacteria, archaea, eukarya, and giant viruses, this study reconstructs phylogenies that reveal giant viruses clustering closely with eukaryotes, suggesting viruses may occupy a distinct yet integral position in the evolutionary landscape. Though perfect declaration of viruses as fourth domain is still dubious, their placement in ToL is as important as any other cellular organism.

This study is carried out to examine the in vitro probiotic properties of Bacillus subtilis B13 (= VTCC 910231), isolated from brackish water in the Cau Hai lagoon, Vietnam. The strain was confirmed to be safe, showing no hemolytic activity and exhibiting strong biofilm formation. It demonstrated notable environmental adaptability, growing across a wide pH range (5-9), showing moderate tolerance at 7% NaCl. B13 produced multiple extracellular enzymes, with the highest activities observed for lipase, protease, and cellulase, and additionally metabolized 25 of the 49 carbohydrates tested (51.0%). Antibiotic susceptibility profiling revealed broad sensitivity, with resistance detected to only 4 of 15 antibiotics, and it was highly sensitive to fluoroquinolones and phenicols. The ethyl acetate extract of its cell-free culture supernatant displayed noticeable inhibitory activity against five Vibrio species, which exhibited inhibition diameters varying from 13.3 ± 0.6 to 21.7 ± 0.6 mm. Moreover, the extract exhibited significant anti-inflammatory effects, achieving concentration-dependent nitric oxide inhibition (IC₅₀ = 28.6 µg/mL) while maintaining high macrophage viability (94.9-97.1%). Chemical analysis by GC-MS and LC-ESI-QTOF/MS identified 34 metabolites, of which 26 were tentatively characterized, including organic acids, fatty acid derivatives, volatile hydrocarbons, and a diverse range of cyclic dipeptides, many of which have previously been reported with antimicrobial and anti-inflammatory activities. Notably, the detection of pre-aurantiamine and leupyrrin A1, together with the broad diversity of cyclic dipeptides, represents a rare feature among B. subtilis strains. These findings emphasise the potential of B13 as a probiotic in aquaculture practices.