Microbial Biotechnology最新文献

The gut microbiota composition in Crohn's disease (CD) patients may influence their response to ustekinumab (UST) therapy. A total of 51 patients with active CD undergoing UST therapy were prospectively enrolled. Clinical activity was evaluated using the Crohn's Disease Activity Index (CDAI), and faecal microbiota were characterised by 16S rRNA sequencing at baseline and week 24. Microbial compositional and functional alterations were assessed, and their correlations with clinical outcomes were examined. At week 24, 46.7% of patients achieved clinical remission and 82.2% achieved clinical response. At baseline, Megamonas (p = 0.009) and Erysipelatoclostridium (p = 0.030) were enriched in the remission group, whereas Fusobacterium (p = 0.016) was more abundant in the non-remission group and correlated positively with C-reactive protein (CRP) but negatively with body mass index (BMI) and serum albumin (ALB). Longitudinal analysis showed that CR patients exhibited increased Clostridium sensu stricto 1 (p = 0.028) and decreased Granulicatella (p = 0.043) after 24 weeks. This study provides real-world evidence supporting the clinical efficacy of UST in Asian patients with active CD. The observed association between elevated baseline Fusobacterium abundance and poorer treatment response suggests a potential microbial influence on therapeutic outcomes. These findings highlight the potential of Fusobacterium as a predictive biomarker for UST response and could provide a rationale for integrating microbiota-modulating strategies to enhance the efficacy of biologics in the future.

This study investigated the impact of ceftriaxone-induced gut microbiota perturbation in neonatal male spontaneous hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats during lactation on the development of juvenile ADHD symptoms. The 5-choice serial reaction time task (5-CSRTT) and open-field test (OFT) were used to evaluate ADHD-related behaviours, and alterations in immune pathways within the microbiota-gut-brain axis were examined. At 3 weeks old, the gut microbiota in both WKY and SHR was significantly disrupted following antibiotic intervention, with these changes persisting 4 weeks after ceftriaxone withdrawal. At the juvenile stage, WKY exhibited inattention, impulsivity, and hyperactivity, while SHR had severe hyperactivity and neuroinflammation. Decreased Chao1 and Shannon indices were positively associated with Treg cells in the spleen, mesenteric lymph nodes (MLN), and IL-10 mRNA expression in the striatum; further, the latter biochemical indices were negatively associated with ADHD symptoms. Lactobacillus and Clostridia_UCG-014 negatively correlated with Treg cells in the spleen, MLN, IL-6, and IL-10 mRNA expression in the striatum; further, these biomarkers were negatively associated with ADHD, which suggested they may contribute to the development of ADHD. In contrast, Muribaculaceae positively correlated with Treg cells in the spleen and MLN, IL-10 mRNA expression, and negatively correlated with ADHD symptoms. These results suggest that early life gut microbiota perturbation persistently contributes to the onset and aggravation of juvenile ADHD through the exacerbation of neuroinflammation and peripheral immune dysfunction.

The global rise of drug-resistant bacterial infections underscores an urgent demand for novel antimicrobial agents. Roseoflavin, a naturally occurring riboflavin analog, has emerged as a promising candidate for drug development. In this study, the industrial workhorse Corynebacterium glutamicum was metabolically engineered towards roseoflavin production. Overexpression of the roseoflavin biosynthetic genes rosABC and the flavin transport gene ribM from the native roseoflavin producer Streptomyces davaonensis was evaluated in C. glutamicum. To further link roseoflavin biosynthesis to its riboflavin precursor, the riboflavin kinase gene ribF from both S. davaonensis and C. glutamicum was evaluated, revealing that its overexpression is essential for enhancing roseoflavin production. The final engineered strain CgRose6 achieved a roseoflavin titer of 17.4 ± 1.5 mg/L and a volumetric productivity of 0.36 ± 0.03 mg/L·h when cultivated in glucose minimal medium supplemented with thiamine, a relevant coenzyme for roseoflavin biosynthesis. These production values are the highest reported by a non-native RoF producer to date and demonstrate the feasibility of using C. glutamicum as a platform for sustainable roseoflavin production, opening avenues for scalable biosynthesis of this valuable antimicrobial compound.

Small-conductance mechanosensitive channels (MscS) are established l-glutamate exporters in industrially relevant bacteria, yet their role in the methylotrophic bacterium Bacillus methanolicus, a promising platform for sustainable methanol-based l-glutamate production, remains unexplored. Our research on B. methanolicus MGA3 identifies its MscS as the sole mechanosensitive channel in this organism and a key exporter of the amino acid l-glutamate, providing valuable insights into its potential for industrial applications. Transcriptomic analysis of B. methanolicus wild type cultured on an l-glutamate production medium revealed downregulation of the fatty acid biosynthesis genes fadR, fadF, mutB2, and acdA, suggesting that fatty acid metabolism is influenced by l-glutamate overproduction, with consequent changes in membrane fluidity likely driving mechanosensitive channel-mediated l-glutamate efflux. The MscS-like channel in B. methanolicus shares structural and functional similarities with MscS in Escherichia coli and with MscCG in Corynebacterium glutamicum. In silico structural predictions show that MGA3 MscS forms a homoheptameric structure with a transmembrane TM-barrel, resembling that of E. coli MscS. The opening mechanism of the channel, driven by membrane dynamics, involves coordinated rotation and flipping of its transmembrane helices, with variations in lipid composition potentially influencing the channel's activity. Additionally, under biotin-replete conditions, where this essential coenzyme supports carboxylases involved in fatty acid biosynthesis, l-glutamate overproduction was suppressed in MGA3. Finally, metabolic engineering experiments inducing MscS gain- and loss-of-function further confirmed the channel's critical role in B. methanolicus amino acid production, proportionally enhancing and reducing l-glutamate efflux, respectively. These findings open doors to novel strategies for engineering B. methanolicus and related methylotrophic organisms for sustainable amino acid production.

Fungal pigments, particularly anthraquinones, play critical roles in food industrial applications due to their vivid hues and bioactive properties. Despite their significance, the functional mechanisms underlying pigment variation and their natural functions remain poorly understood. Here, we investigate the genetic and biochemical basis of anthraquinone-mediated pigmentation in the thermophilic fungus Thermomyces dupontii. Through a combination of transcriptomic, biochemical and chemical analyses, we identified the flavin-dependent halogenase gene (hal) as a key controller of anthraquinone chlorination, a process essential for fungal pigmentation and metabolic responses to low temperature stress. Disruption of hal abolished chlorinated anthraquinone production, reduced colony pigmentation and impaired ATP production. We characterised novel chlorinated and dichlorinated anthraquinones, highlighting chlorination's role in enhancing the structural diversity of anthraquinones and fungal pigmentation. Detailed bioassays indicated that hal-mediated anthraquinone chlorination contributes to fungal survival under cold stress by enhancing two distinct energy modes. This study provides new insights into the ecological significance of fungal pigmentation and opens avenues for the biotechnological exploitation of fungal pigments in food industrial and medical research.

Infectious diseases continue to pose a significant global health challenge, necessitating innovative approaches for predicting outbreaks, detecting variants, conducting contact tracing, discovering new drugs and managing misinformation. Artificial intelligence (AI) has significantly supported work in these areas, particularly during the COVID-19 pandemic. However, the benefits of AI must be equitably distributed, and its use must be responsible and inclusive. As various nations implement AI regulations, the global nature of AI necessitates international collaboration to establish ethical guidelines and governance frameworks. In response to these needs, the Global South AI for Pandemic & Epidemic Preparedness & Response Network (AI4PEP) is leading a multinational effort across 16 countries to strengthen public health systems through responsible, Southern-led AI solutions. This opinion piece highlights AI4PEP's initiatives in Latin America and the Caribbean (LAC), examining the region's AI governance models and the challenges they present. By lowering barriers to AI adoption and fostering equitable access to AI-driven public health innovations, our network empowers researchers, healthcare professionals and policymakers in LAC to harness AI for infectious disease preparedness and response, ultimately improving health outcomes in low- and middle-income countries.

The Pseudomonas syringae complex WHOP genomic island underpins virulence in woody hosts by mediating the catabolism of aromatic compounds. However, the biochemical functions of the ipoABC and dhoAB operons and the regulatory gene whpR remain unknown. Comparative genomics revealed WHOP-like clusters beyond P. syringae, found in diverse plant-associated, environmental and clinical bacteria, including indole degraders. We propose that ipoABC and dhoAB mediate indole degradation via anthranilate, linking indole detoxification to central metabolism through the β-ketoadipate pathway. In the olive pathogen P. savastanoi pv. savastanoi, ipoABC promotes indole degradation, indigo production, cell aggregation and biofilm formation. WhpR, an AraC-family regulator structurally related to CuxR and ToxT, defines a regulon comprising repression of most WHOP operons along with genes outside this region, including trpAB, reflecting integrated regulation of indole catabolism and tryptophan biosynthesis. In line with the observed transcriptional repression of WHOP genes, deletion of whpR led to hypervirulence and significantly altered bacterial fitness in woody olive plants. These findings define the WHOP region as a regulatory hub linking indole detoxification, multicellular behaviour and virulence, emerging as a target for novel control strategies against woody plant diseases.

Rapid and reliable analytical techniques play important roles in various research fields and are particularly crucial for diagnosing infectious diseases in clinical settings. African swine fever (ASF) is a devastating viral pig disease for which no effective vaccine is available. The ongoing ASF pandemic has highlighted the importance of rapid and accurate diagnosis, which enables the timely implementation of control and eradication measures. In this study, a ready-to-use bioluminescence immunosensor based on a split-nanoluciferase (NanoLuc) reporter system was proposed for the one-step sensitive detection of ASF virus (ASFV) antibodies. Specifically, the NanoLuc subunits SmBiT/LgBiT were each genetically fused to the ASFV p30 protein and protein G and used as probes. The simultaneous binding of the probes to ASFV IgGs induced the reconstitution of functional NanoLuc, which can generate a strong bioluminescent signal output by catalysing the substrate furimazine. This immunosensor allows the rapid and homogeneous detection of ASFV antibodies in solution, requiring only one incubation step of 10 min. This immunosensor also has high sensitivity, high specificity, and a wide dynamic range and is particularly promising for point-of-care testing. Comparative analysis of clinical samples validated the reliability and robustness of this approach and demonstrated high consistency with enzyme-linked immunosorbent assay (ELISA) results (concordance rate: 98.71%). These results suggest that the proposed immunosensor provides an attractive alternative to conventional immunoassays and could be easily repurposed by generating specific probes for antibody detection in other diseases.

Ethanol stress poses a considerable challenge for Saccharomyces cerevisiae during fermentation. Strains carrying an extra copy of chromosome III exhibit enhanced ethanol tolerance. Here, we investigated the underlying mechanisms of this tolerance, focusing on gene dosage effects and differential gene expression under ethanol stress. We compared the gene expression profiles of a strain with three copies of chromosome III and its derivative with two copies, exposed to 6% and 10% ethanol. Our analysis identified TUP1, located on chromosome III, as a key regulator of the ethanol stress response. Deleting one copy of TUP1 in the tolerant strain diminished its ethanol tolerance, suggesting that chromosome III aneuploidy in ethanol-tolerant strains enhances adaptive responses by increasing TUP1 copy number. Our findings offer insights into the genetic basis of ethanol tolerance, with potential applications for optimising industrial fermentation processes and understanding the role of aneuploidy in the domestication of industrial yeasts.

Ethanol stress poses a considerable challenge for Saccharomyces cerevisiae during fermentation. Strains carrying an extra copy of chromosome III exhibit enhanced ethanol tolerance. Here, we investigated the underlying mechanisms of this tolerance, focusing on gene dosage effects and differential gene expression under ethanol stress. We compared the gene expression profiles of a strain with three copies of chromosome III and its derivative with two copies, exposed to 6% and 10% ethanol. Our analysis identified TUP1, located on chromosome III, as a key regulator of the ethanol stress response. Deleting one copy of TUP1 in the tolerant strain diminished its ethanol tolerance, suggesting that chromosome III aneuploidy in ethanol-tolerant strains enhances adaptive responses by increasing TUP1 copy number. Our findings offer insights into the genetic basis of ethanol tolerance, with potential applications for optimising industrial fermentation processes and understanding the role of aneuploidy in the domestication of industrial yeasts.