Microbial Biotechnology最新文献

The gut-testis axis enables gut microbes to influence host reproduction; nonetheless, the specific role of microbial genetic variation in this process remains elusive. In this study, using Caenorhabditis elegans (C. elegans) as a model organism, we identified 46 Escherichia coli (E. coli) strains that markedly enhanced C. elegans fertility. Of them, 26 strains were mutant variants capable of mitigating cyclophosphamide (CTX)-induced reproductive disorders in C. elegans. To investigate their application, we constructed probiotics to validate their effectiveness in mouse reproduction. The engineering probiotic Ecn Δpal significantly improved spermatogenesis in mice with CTX-induced reproductive disorders. Finally, comprehensive metabolome and transcriptome analysis suggested that the purine metabolism pathway may contribute to ameliorating cyclophosphamide-induced male reproductive toxicity. Overall, our study provides novel insights into the impact of gut microbial genetic variation on host reproduction and elucidates novel therapeutic avenues for mitigating CTX-induced male reproductive toxicity.

The phyllosphere, the aerial surfaces of plants, represents a primary entry point for airborne fungal pathogens, posing a critical challenge to plant health and productivity. The phyllosphere hosts diverse microbial communities that play a pivotal role in suppressing foliar pathogens through complex ecological interactions. In this mini review, we synthesise recent advances in understanding how phyllosphere microbial diversity contributes to fungal pathogen suppression through multiple ecological mechanisms, including resource competition, secretion of antifungal metabolites, contact-dependent killing and activation of host immune responses. We highlight emerging evidence on the role of viruses in controlling fungal pathogens and propose a conceptual framework based on virus-mediated strategies for fungal disease control. We emphasise that better mechanistic understanding of plant–fungus–microbiota interactions is critical to developing sustainable and microbiota-based approaches for plant resilience enhancement and global food security within a One Health framework.

The phyllosphere, the aerial surfaces of plants, represents a primary entry point for airborne fungal pathogens, posing a critical challenge to plant health and productivity. The phyllosphere hosts diverse microbial communities that play a pivotal role in suppressing foliar pathogens through complex ecological interactions. In this mini review, we synthesise recent advances in understanding how phyllosphere microbial diversity contributes to fungal pathogen suppression through multiple ecological mechanisms, including resource competition, secretion of antifungal metabolites, contact-dependent killing and activation of host immune responses. We highlight emerging evidence on the role of viruses in controlling fungal pathogens and propose a conceptual framework based on virus-mediated strategies for fungal disease control. We emphasise that better mechanistic understanding of plant–fungus–microbiota interactions is critical to developing sustainable and microbiota-based approaches for plant resilience enhancement and global food security within a One Health framework.

The gut-testis axis enables gut microbes to influence host reproduction; nonetheless, the specific role of microbial genetic variation in this process remains elusive. In this study, using Caenorhabditis elegans (C. elegans) as a model organism, we identified 46 Escherichia coli (E. coli) strains that markedly enhanced C. elegans fertility. Of them, 26 strains were mutant variants capable of mitigating cyclophosphamide (CTX)-induced reproductive disorders in C. elegans. To investigate their application, we constructed probiotics to validate their effectiveness in mouse reproduction. The engineering probiotic Ecn Δpal significantly improved spermatogenesis in mice with CTX-induced reproductive disorders. Finally, comprehensive metabolome and transcriptome analysis suggested that the purine metabolism pathway may contribute to ameliorating cyclophosphamide-induced male reproductive toxicity. Overall, our study provides novel insights into the impact of gut microbial genetic variation on host reproduction and elucidates novel therapeutic avenues for mitigating CTX-induced male reproductive toxicity.

Flavonoids are valuable for pharmaceutical, cosmetic and food applications. However, poor solubility and bioavailability limit their widespread use. Biotechnological glycosylation of flavonoids helps address these limitations, but such bioprocesses remain constrained by the cost and availability of uridine diphosphate glucose (UDPG) and the inherent toxicity of flavonoids. In this study we demonstrate that Escherichia coli W is an optimal microbial host for glycosylation bioprocesses using sucrose as a carbon and UDPG source. Escherichia coli W outperforms the model E. coli K12 strain in terms of flavonoid tolerance and glycosylation capabilities. Optimization of sucrose metabolism through adaptive laboratory evolution (ALE) and targeted metabolic engineering to reroute glucose metabolism to UDPG further enhances E. coli W's glycosylation abilities. We validated our glycosylation platform for bench-scale production of chrysin-7-O-glucoside (C7O), a valuable flavonoid glucoside, overcoming key challenges related to the low solubility and bioavailability of its precursor, chrysin. To address bioavailability limitations, we implemented a fed-batch bioprocess in a 3 L bioreactor which returned 1844 mg/L (3.3 mM) C7O, a specific production rate of 0.17 mmol C7O/g DCW·h and a 25.24 mg/g Yp/s after 76 h. An 82.1% yield (1515 mg/L C7O) post extraction and purification demonstrates the efficiency and scalability of the process for industrial bioproduction.

Salmonella enterica (SE) is one of the most prevalent enteric pathogens globally and infects humans through contaminated food and water sources. The rising trend of antibiotic-resistant SE strains poses a critical threat to public health. Bacteriophage-encoded endolysins evolve a promising alternative as antimicrobial agents for combating SE infections. These enzymes target the peptidoglycan layer of bacterial cells, causing cell lysis and death. However, the use of endolysins against Gram-negative bacteria is challenging due to the composition of the outer membrane, which acts as a barrier preventing the endolysins from reaching the peptidoglycan layer. KL9P is a short amphipathic peptide containing both hydrophobic and hydrophilic regions, enabling it to interact with membranes and aqueous environments. In this study, an endolysin ENDO-1252, a Salmonella bacteriophage-encoded enzyme, was fused with a short peptide KL9P and produced an advanced endolysin, ENDO-1252/KL9P, which enhanced its ability to lyse multiple serovars of SE. ENDO-1252/KL9P exhibited potent lytic activity against SE strains with optimal bactericidal effects observed at 20 μM and incubation at 37°C in 20 mM HEPES buffer (pH 7.4). The lytic activity of this endolysin was also evaluated under various conditions, including pH ranges and temperatures, revealing that ENDO-1252/KL9P retained significant lytic activity across a range of temperatures (25°C–40°C) and pH values (6.0–9.0). The fusion protein demonstrated the highest lytic efficiency against SE serovars, specifically S. Enteritidis, S. Heidelberg, and S. Pullorum. Immunofluorescence analysis confirmed the binding of ENDO-1252/KL9P to the bacterial cell wall, indicating the co-localization with the peptidoglycan layer. These results suggest that ENDO-1252/KL9P is a promising antibacterial agent inhibiting predominant serovars of SE, showing enhanced lytic activity without outer membrane permeabilizers.

Antibiofilm molecules can enhance the effectiveness of antibiotics and prevent biofilm formation. Antarctic marine bacteria have been found to secrete antibiofilm molecules, likely as part of a strategy for competitive survival. The protein-polysaccharide complex CATASAN, produced by the Antarctic bacterium Psychrobacter sp. TAE2020, has been shown to interfere with all stages of Staphylococcus epidermidis biofilm development. This study investigates the contribution of PsyOmp38, the protein component of CATASAN, to the complex's antibiofilm activity. The protein was heterologously expressed in Escherichia coli, purified, and characterised, revealing its ability to inhibit Staphylococcus epidermidis adhesion to surfaces, interfere with biofilm formation, and disrupt mature biofilms. Following biocompatibility assessment, PsyOmp38 was tested in combination with vancomycin as a potential treatment for established infections, revealing a reduction in the minimum biofilm eradication concentration (MBEC) of vancomycin. The potential of PsyOmp38 for material functionalisation was also explored. The protein was deposited onto silicone-based surfaces, and the coated materials were tested in a continuous-flow system that simulated real-life conditions. Additionally, the three-dimensional structure of PsyOmp38 was predicted and compared with homologous proteins. The structural analysis not only revealed the unique features of PsyOmp38 but also provided important insights into the molecular mechanisms underlying its antibiofilm activity.

This study investigated temporal dynamics in reactor performance and microbial community structure during anaerobic digestion of sewage sludge when the temperature was changed from 37°C to 55°C, followed by an increase in organic loading rate (OLR). Performance instability was observed immediately following the temperature increase and in the end of the study when the OLR was 11.1 ± 0.3 kgVS m⁻³d⁻¹. The specific methane production peaked at 0.31 ± 0.06 Nm³ kg⁻¹ volatile solids (VS) during thermophilic operation and when the OLR was 3.5 ± 0.9 kgVS m⁻³d⁻¹. Using metagenomic sequencing, 304 species-representative genome bins (SGB) were assembled. Network analysis revealed that 186 SGB were associated with thermophilic conditions and several new species putatively involved in key reactor functions were identified. When reactor function initially stabilised, two hydrogenotrophic and one aceticlastic methanogen (Methanothermobacter spp. and Methanosarcina thermophila), the hydrolytic Coprothermobacter proteolyticus, and putative syntrophic propionate oxidisers (e.g., Pelotomaculaceae) had high relative abundance. During the peak in specific gas production, the community was dominated by one hydrogenotrophic Methanothermobacter species coexisting with syntrophic acetate oxidising bacteria (Thermacetogenium phaeum and other species). Finally, when the reaction function deteriorated due to high OLR, new hydrolytic taxa emerged and the same aceticlastic methanogen as seen during the initial acclimatisation phase returned.

This study investigated temporal dynamics in reactor performance and microbial community structure during anaerobic digestion of sewage sludge when the temperature was changed from 37°C to 55°C, followed by an increase in organic loading rate (OLR). Performance instability was observed immediately following the temperature increase and in the end of the study when the OLR was 11.1 ± 0.3 kgVS m⁻³d⁻¹. The specific methane production peaked at 0.31 ± 0.06 Nm³ kg⁻¹ volatile solids (VS) during thermophilic operation and when the OLR was 3.5 ± 0.9 kgVS m⁻³d⁻¹. Using metagenomic sequencing, 304 species-representative genome bins (SGB) were assembled. Network analysis revealed that 186 SGB were associated with thermophilic conditions and several new species putatively involved in key reactor functions were identified. When reactor function initially stabilised, two hydrogenotrophic and one aceticlastic methanogen (Methanothermobacter spp. and Methanosarcina thermophila), the hydrolytic Coprothermobacter proteolyticus, and putative syntrophic propionate oxidisers (e.g., Pelotomaculaceae) had high relative abundance. During the peak in specific gas production, the community was dominated by one hydrogenotrophic Methanothermobacter species coexisting with syntrophic acetate oxidising bacteria (Thermacetogenium phaeum and other species). Finally, when the reaction function deteriorated due to high OLR, new hydrolytic taxa emerged and the same aceticlastic methanogen as seen during the initial acclimatisation phase returned.

Microorganism culturing is essential in microbiological research, with the selection of suitable culture media being critical for successful microbial growth. Traditionally, this selection has relied on empirical knowledge or trial and error, often resulting in inefficiency. In this study, we analysed nutrient compositions from the MediaDive database to construct a dataset of 2369 media types. Leveraging this dataset and microbial 16S rRNA sequences, we developed 45 binary classification models using the XGBoost algorithm. These models demonstrated strong predictive performance, achieving accuracies ranging from 76% to 99.3%, with the top-performing models for J386, J50 and J66 media reaching 99.3%, 98.9% and 98.8%, respectively. The models effectively predicted growth conditions for various human gut microbes, confirming their practical utility. This research improves the efficiency of microbial cultivation and highlights the potential of machine learning to optimise culture media selection and advance microbiological studies.