[Objective] To investigate the in vitro uric acid degradation performance and physiological and biochemical characteristics of Limosilactobacillus fermentum H3260 isolated from human feces and examine the effects of this strain on the serum uric acid level and gut microbiota in the mouse model of hyperuricemia, providing scientific evidence for the development of functional food for the prevention and treatment of hyperuricemia. [Methods] HPLC and the uric acid production assay were employed to determine the abilities of the target strain to degrade uric acid, adenosine, and nucleosides and to inhibit xanthine oxidase. The probiotic characteristics of the strain were evaluated by antimicrobial sensitivity tests and in vitro tolerance tests. The uric acid-lowering effect of L. fermentum H3260 was verified by in vivo experiments. [Results] L. fermentum H3260 was screened out. The strain exhibited degradation rates of (86.84±0.03)% for uric acid, (60.84±2.21)% for adenine, and (100.00±0.00)% for nucleosides, along with an inhibition rate of 22.48% for xanthine oxidase. The strain was sensitive to seven common antibiotics, including erythromycin, ceftriaxone, penicillin G, and chloramphenicol. After treatment in 0.3% bile salt for 2.5 h, the bacterial count remained above 1.00×10⁶ CFU/mL. Animal experiments showed that the strain significantly reduced uric acid, creatinine, and blood urea nitrogen in hyperuricemic mice and regulate the gut microbiota to alleviate hyperuricemia. [Conclusion] We successfully screened out a strain L. fermentum H3260 capable of efficiently degrading uric acid, adenosine, and nucleosides. The strain exhibited good physiological and biochemical characteristics in vitro and significantly improved hyperuricemia-related indicators and regulated the gut microbiota in vivo, showing potential as an elite strain for the prevention and treatment of hyperuricemia.

[Objective] Black soil regions are globally critical for grain production, with their soil health directly impacting world food security and ecological stability. These regions hold significant strategic importance for sustainable agriculture and human health. In recent years, rapid advancements in microbiome research methodologies have highlighted the pivotal role of soil microorganisms in the sustainable utilization and health management of black soil. [Methods] To systematically summarize the research status and trends in black soil microorganisms, we employed “bibliometrix” R package and VOSviewer to conduct bibliometric analysis. We quantitatively analyzed the literature from the Web of Science core collection (2014-2024) and manually screened the abstracts. [Results] The results revealed a surge in the research on black soil microorganisms after 2021, with China, Russia, and the United States being the most prolific contributors. Leading institutions included the Chinese Academy of Sciences, University of Chinese Academy of Sciences, Northeast Agricultural University, Heilongjiang Academy of Agricultural Sciences, and Chinese Academy of Agricultural Sciences. Key findings were predominantly published in Applied Soil Ecology, Soil Biology & Biochemistry, and Eurasian Soil Science. Current research focuses on microbial networks, biochar applications, and rhizosphere microecology, emphasizing the roles of microorganisms in soil fertility regulation, environmental remediation, soil improvement, climate change responses, and farming system optimization. Studies also explore interactions between microorganisms and environmental factors such as soil aggregates, physicochemical properties, and enzyme activities, with a growing shift toward mechanism insights. [Conclusion] Over the past decade, research on black soil microbiota has rapidly advanced, with current focus on the role of microorganisms in soil fertility enhancement and sustainable utilization. Future studies should integrate cutting-edge technologies such as microbiomics, metagenomics, metatranscriptomics, and metabolomics to comprehensively analyze microbial community distribution, functionality, and regulatory mechanisms. Ultimately, this will provide a robust theoretical and technical foundation for the sustainable use and health enhancement of black soil resources.

[Objective] To clarify phyllosphere microbial responses to the invasion of areca palm velarivirus 1 (APV1), a virus causing yellow leaf disease of areca (Areca catechu), and provide a theoretical basis and technical support for the study of phyllosphere micro-ecology, exploration of excellent biocontrol resources, and green prevention and control of yellow leaf disease of areca. [Methods] We collected healthy leaves, mildly diseased leaves, and severely diseased leaves of areca. The phyllosphere microbial community structure and diversity were compared by high-throughput sequencing and bioinformatics methods. Furthermore, functional differences of phyllosphere microbial communities were analyzed. [Results] The dominant bacterial phyla in the phyllosphere of areca included Actinobacteriota, Proteobacteria, Acidobacteriota, Firmicutes, and Myxococcota, while the dominant fungal phyla were Ascomycota and Basidiomycota. As the disease became increasingly severe, bacterial richness initially increased then decreased while fungal richness initially decreased then increased. However, both bacterial diversity and fungal diversity showed a trend of first increasing and then decreasing. Firmicutes and Basidiomycota served as indicators of mildly diseased areca, with the relative abundance showing consistent trends with alpha diversity. The healthy plants and the diseased plants showed different phyllosphere microbial functions. Specifically, the environmental information processing function was significantly higher in severely diseased areca plants than in healthy ones. Additionally, the relative abundance of symbiotroph fungi in the phyllosphere were significantly higher in severely diseased areca plants than in healthy ones. [Conclusion] The yellow leaf disease significantly alters the phyllosphere microbial community structure and diversity of areca, with greater changes during the early disease stage. This suggests that areca may defend against APV1 infection by recruiting beneficial microorganisms, regulating cellular metabolism and biochemical reactions, and activating autoimmunity.

As a major risk factor for cardiovascular disease worldwide, hypertension poses threats that cannot be ignored. In recent years, the role of gut microbiota in the pathogenesis of hypertension has gradually become a research hotspot. This review systematically explores the relationship between gut microbiota and hypertension and elaborates on the mechanisms of gut microbiota regulation of blood pressure by mediating inflammatory responses, influencing the microbiota-gut-brain axis, and producing specific metabolites. Furthermore, this article discusses the potential application value of gut microbiota-based intervention strategies in the prevention and treatment of hypertension and reveals the potential targets and evidence of gut microbiota in the treatment of hypertension and its complications, paving a new way for the exploration of therapeutic methods.

The puparium of Hermetia illucens is rich in chitin and protein, while efficient and environmentally friendly utilization methods remain to be developed. [Objective] To isolate chitinolytic bacteria from the puparium pile of H. illucens and explore their potential in puparium biotransformation. [Methods] Strains were isolated by the plate screening method and identified by 16S rRNA gene sequencing. The 3,5-dinitrosalicylic acid (DNS) method was employed to determine the chitinase activity. Whole genome sequencing by PacBio HiFi was conducted to elucidate the degradation mechanism. The application potential of the strain was explored by puparium fermentation experiments. [Results] Among the seven isolated strains, Bacillus cereus BSF-CH1 showed the highest chitinase activity, reaching a maximum chitinase activity of 0.48 U/mL on the second day of fermentation. The genome of BSF-CH1 contained three chitinase genes, seven chitin deacetylase genes, and four chitodextrinase genes. Puparium biotransformation experiments showed that BSF-CH1 could degrade 47.2% of puparium mass within 7 days, with degradation rates of 64.6% and 59.1% for chitin and protein, respectively. [Conclusion] This study reports an efficient chitinolytic bacterium isolated from the puparium of H. illucens, providing new insights into the puparium biotransformation and having important implications for promoting the sustainable development of the H. illucens industry.

Glutamate waste liquid is the waste produced in the production process of glutamic acid, with low pH, high ammonium, and high sulfate. The waste liquid contains glutamic acid and can be used as a raw material to produce poly-γ-glutamic acid (γ-PGA), achieving the recycling of waste liquid. [Objective] To investigate the inhibitory effect of glutamate waste liquid on γ-PGA synthesis, we used Bacillus subtilis KH2 to synthesize γ-PGA and evaluated the inhibitory effect of glutamate waste liquid on the synthesis of γ-PGA. [Methods] Comparative transcriptomics was employed to excavate the key genes and inhibitory factors involved in γ-PGA synthesis, and key gene overexpression and knockout were conducted to identify the inhibitory factors. Fermentation experiments were then performed for verification. [Results] The glutamate waste liquid as the substrate for production of γ-PGA by fermentation showed significant inhibitory effects. A total of 1 819 significantly differentially expressed genes were identified, including 952 genes with significantly up-regulated expression and 867 genes with significantly down-regulated expression. The transcript levels of 10 genes (alsS, pgsA, gltT, budA, fumC, ptsG, racE, opuAB, acoC, and rocG) involved in γ-PGA synthesis of B. subtilis KH2 changed significantly during primary fermentation and glutamate waste liquid fermentation. Eight down-regulated genes (alsS, pgsA, gltT, budA, fumC, ptsG, racE, and opuAB) were overexpressed, which increased the production of γ-PGA by 91.20%, 120.77%, 137.50%, 36.44%, 40.85%, 104.58%, 65.67%, and 69.72%, respectively. The overexpression of pgsA, gltT, ptsG, racE, and opuAB increased glutamic acid utilization by 11.57%, 35.53%, 12.83%, 21.43%, and 14.80%, respectively. The overexpression of alsS, budA, and fumC had no obvious improving effect on the utilization of glutamic acid. The knockout of two up-regulated genes (acoC and rocG) had little effect on γ-PGA production and glutamic acid utilization. [Conclusion] The downregulation of ptsG, gltT, racE, pgsA, and fumC in waste liquid fermentation has significant effects on substrate utilization, glutamic acid configuration conversion and polymerization, and TCA cycle, which reduces the synthesis efficiency of γ-PGA. This study reveals the inhibitory mechanism of glutamate waste liquid in γ-PGA synthesis and provides a sustainable biotechnology for the production of value-added biopolymers from industrial waste liquid.

[Objective] Black soil acidification may exacerbate the soil degradation processes and reduce microbial functions, thus threatening the crucial role of the northeast region in guaranteeing the food security of China. Unraveling the impacts of soil acidification on the soil microbial community and its underlying mechanisms can help clarify the relationship between soil organic carbon (SOC) stabilization and soil acidification. [Methods] Soil samples with different acidification degrees were collected from the corn belts of black soil regions. The changes of living microbial groups in the soil samples with different pH were investigated by the phospholipid fatty acid (PLFA) analysis. Additionally, the relationship between changes in the soil physicochemical properties and microbial community composition was analyzed. [Results] A threshold effect of black soil acidification on SOC was identified in the corn belts. Moderate acidification did not cause significant changes in SOC. However, when pH dropped below a certain threshold (6.75), further acidification resulted in a significant loss of SOC. The cation buffering effect in soil changed significantly with different acidification degrees. Calcium ion was primarily responsible for buffering black soil acidification, while when the pH fell below 6.00, both calcium and magnesium ions buffered the acidification. Soil acidification imposed noticeable stress on soil microorganism growth. Different microbial groups exhibited an S-shaped response pattern, with PLFA content initially decreasing, remaining stable within the range of pH 5.25-6.25, and subsequently declining as acidification progressed. However, different microbial groups exhibited varying sensitivities to soil acidification. Gram-negative bacteria were the most sensitive, followed by Gram-positive bacteria and arbuscular mycorrhizal fungi. Fungi, particularly arbuscular mycorrhizal fungi, may play a crucial role in stabilizing SOC during soil acidification. [Conclusion] Soil acidification significantly alters the structure of the living microbial community, primarily through changes in cation exchange capacity and substrate availability, which further affect SOC accumulation. These findings provide scientific support for developing management strategies to alleviate black soil degradation and acidification.

Microbial deodorization is an effective technology for treating odorous waste gases, in which microbial strains play a decisive role. [Objective] To screen the strains capable of degrading dimethyl disulfide (DMDS) and investigate their degradation efficiency and ability to produce surfactants under various conditions. [Methods] DMDS, a typical sulfur-containing odorous organic compound, was selected as the sole carbon source. A strain R1 capable of simultaneously producing biosurfactants and degrading DMDS was isolated from mangrove sludge. The strain was identified based on the physiological and biochemical characteristics analysis and 16S rRNA gene sequencing. The types of self-produced biosurfactants were determined using infrared spectroscopy and nuclear magnetic resonance spectroscopy analysis. [Results] Based on physiological and biochemical characteristics and 16S rRNA gene sequence, strain R1 was identified as Achromobacter sp. The strain was capable of degrading DMDS, with optimal degradation conditions of an initial DMDS concentration of 12.49 mg/L, a system temperature of 30 ℃, and an inoculum amount of 1.0 g/L, under which the DMDS degradation rate reached 70.74%. Emulsification experiments showed that strain R1 can use DMDS as a carbon source to produce biosurfactants, which were identified as glycolipids through nuclear magnetic resonance and infrared spectroscopy. [Conclusion] The main intermediate product in the biodegradation of DMDS is methyl mercaptan, and the transformation rate of sulfur to SO₄^2- is 65.99%. Strain R1 exhibits impressive performance in degrading DMDS and producing biosurfactants.

[Objective] To systematically investigate the substrate promiscuity and catalytic performance of three UDP-glycosyltransferases: CsUGT75L12 (Camellia sinensis), CiUGT11 (Chrysanthemum indicum), and UGT73B1 (Arabidopsis thaliana). [Methods] The recombinant proteins of plant glycosyltransferases were heterologously expressed in Escherichia coli BL21(DE3) and purified for in vitro enzymatic assays. In vitro enzymatic reactions of the purified recombinant proteins were performed with six flavonoids including flavones (apigenin and acacetin) and flavanones (naringenin, eriodictyol, isosakuranetin, and hesperetin). The enzymatic products were characterized by HPLC and LC-MS and the conversion rates were calculated through comparative HPLC peak area analysis. [Results] CsUGT75L12, CiUGT11, and UGT73B1 exhibited broad substrate promiscuity towards the six tested flavonoids. The primary products were identified as flavonoid-7-O-glucosides. Notably, CiUGT11 and UGT73B1 demonstrated exceptional catalytic efficiency, achieving >96% conversion rates for hesperetin and naringenin. Leveraging this activity, we engineered CiUGT11 and UGT73B1 with high efficiency to produce hesperetin-7-O-glucoside and naringenin-7-O-glucoside through precursor feeding in E. coli. [Conclusion] The three glycosyltransferases display remarkable versatility in flavonoid recognition, with conserved preference for the C7-OH position. CiUGT11 and UGT73B1 show high catalytic efficiency for six flavonoids. These findings provide candidate gene elements for the efficient microbial production of flavonoid glycosides.

[Objective] To investigate the structural characteristics of microbial consortia in different concentrations of petroleum hydrocarbons, cultivate efficient petroleum hydrocarbon-degrading microbial consortia, and mine the strain resources capable of degrading petroleum hydrocarbons. [Methods] We used 0# diesel as the sole carbon source to domesticate oil-contaminated soil samples through five successive generations by gradually increasing the 0# diesel concentration. The structural changes of microbial consortia were uncovered by 16S rRNA gene amplicon sequencing. The strains with petroleum hydrocarbon-degrading potential were isolated and purified via dilution plating and streaking. Finally, the improved 2,6-dichlorophenol indophenol (DCPIP) cultivation system was employed to identify efficient degrading strains. [Results] During domestication, when the concentration of 0# diesel was raised to 7 000 mg/L, the relative abundance of petroleum hydrocarbon-degrading bacteria including Bacteroidota and Bacillota significantly increased. A total of 58 bacterial strains belonging to 25 genera, 22 families of 4 phyla were isolated, including 31 (53.45%) strains of Pseudomonadota, 13 (22.41%) strains of Actinomycetota, 11 (18.97%) strains of Bacillota, and 3 (5.17%) strains of Bacteroidota. From the isolated strains, 18 petroleum hydrocarbon-degrading strains were screened out. [Conclusion] Through gradient domestication, seven natural microbial consortia were successfully enriched, achieving over 70% degradation of petroleum hydrocarbons at 7 000 mg/L of 0# diesel. Amplicon sequencing revealed that varying 0# diesel concentrations altered the microbial consortium structure. Additionally, 18 strains capable of using 0# diesel as the sole carbon source were identified, providing potential microbial resources for the bioremediation of oil-contaminated soil.