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.

[Objective] To investigate the mechanism of the induced cross resistance of drug-resistant mutants of Escherichia coli to tigecycline in vitro. [Methods] We used doxycycline hydrochloride and the mutation preventive concentration (MPC) method to induce the drug resistance mutation of Escherichia coli ATCC 25922, and the drug resistance spectra of the mutants were determined. Genome-wide next-generation sequencing was utilized to analyze the mutations of key differentially expressed resistance genes of ATCC 25922 and the mutant with the highest resistance index. RT-PCR was used to determine the transcription levels of the key differentially expressed resistance genes of the mutant with the highest resistance index according to the whole genome sequencing results. The expression of key differentially expressed resistance genes in the mutant with the highest resistance index was knocked down by siRNA. [Results] Three drug-resistant E. coli mutants Y_3.2-2, Y₆₄, and Y_128-2 with different degrees of resistance to tigecycline were obtained after stepwise induction of drug resistance mutation, with the resistance following the order of Y_3.2-2<Y₆₄<Y_128-2. All the mutants showed multi-drug resistance. Fourteen resistance genes were detected with varying degrees of base mutations and amino acid mutations. In the mutant Y_128-2 with the highest resistance index, the expression of acrA, acrE, acrF, acrS, plsC, rpsJ, acrB, and macA was up-regulated, while that of tolC, marA, sdiA, and macB was down-regulated. The resistance genes rpsJ and plsC in Y_128-2 were successfully interfered with at tigecycline concentrations of 1×MIC and 1/2×MIC, and the strain regained sensitivity to tigecycline. [Conclusion] Y_128-2 develops resistance to tigecycline by the overexpression of the ribosome binding site gene rpsJ and the bacterial cell membrane permeability-related resistance gene plsC.

Saline-alkali land is a common type of degraded soil with wide distribution across the globe. Among all types of saline-alkali land, soda saline-alkali land, characterized by the coexistence of high salinity and alkalinity, is particularly difficult to be managed and represent a major obstacle to the effective utilization of soil resources. Arbuscular mycorrhizal fungi (AMF) enhance plant growth and survival by improving nutrient uptake and increasing stress resistance, offering promising potential for the reclamation and utilization of saline-alkali land. [Objective] To explore how the structures and diversity of the AMF community vary along a soda saline-alkaline stress gradient in response to stress and other environmental factors. [Methods] We collected soil samples subjected to varying levels of soda saline-alkaline stress from Changling County and Da’an City in Jilin Province. The sampling sites included Suaeda glauca-covered wildland (pH 10.0-10.5), unvegetated bare land (pH 9.5-10.0), and maize (Zea mays L.) farmlands under varying levels of stress (pH 8.5-10.0). The structures and diversity of AMF communities in these soil samples were analyzed by Illumina-based 18S rRNA gene sequencing. [Results] AMF communities were predominantly composed of Entrophospora, Funneliformis, Rhizoglomus, and Dominikia. The relative abundance of AMF was significantly positively correlated with soil total carbon, total nitrogen, total phosphorus, and available nitrogen, and it was significantly negatively correlated with soil pH, electrical conductivity, and salt content. The AMF community structure was significantly associated with soil total carbon and pH. The Shannon diversity (alpha diversity) of AMF showed significantly positive correlations with total phosphorus and salt content, while the AMF community structure dispersion (beta diversity) was significantly negatively correlated with electrical conductivity. Moreover, the alpha diversity and beta diversity of AMF had a significantly negative correlation. [Conclusion] Saline-alkaline stress exerted homogeneous selection on the AMF community, leading to reduced community size, decreased beta diversity, increased alpha diversity, and altered community composition.

[Objective] To study the effects of the glycosyltransferase WekO involved in O-antigen synthesis on the biological characteristics of avian pathogenic Escherichia coli (APEC). [Methods] The mutant strain ΔwekO of APEC O₁ was constructed by Red homologous recombination, and the complementary strain CΔwekO was then constructed. The lipopolysaccharide (LPS) profile of each strain was identified by silver staining. Simultaneously, the growth rate and swimming motility were measured. The reactivity of each strain with rabbit anti-O₁ serum was determined by Western blotting. The ability of ΔwekO to form biofilms was measured by the crystal violet staining method. DF-1 cells were used to evaluate the adhesion and invasion of ΔwekOin vitro. Subsequently, chicks were selected as an animal model to evaluate the pathogenicity of ΔwekO. [Results] The mutant strain ΔwekO and the complementary strain CΔwekO were constructed. The LPS profile of ΔwekO was incomplete compared with that of the wild-type strain. The mutant lacked O-antigen bands and showed no reactivity to anti-O₁ serum. There was no significant difference in growth rate between different strains (P>0.05). However, the motility and biofilm formation capabilities of ΔwekO decreased (P<0.001). Additionally, ΔwekO demonstrated weakened adhesion to DF-1 cells (P<0.001) and demonstrated weakened invasion to DF-1 cells (P<0.01). Also, ΔwekO reduced pathogenicity to 7-day-old chicks (P<0.05). [Conclusion] The deletion of wekO results in impaired O-antigen synthesis, incomplete LPS profile, loss of flagellar and biofilm formation capabilities, and reduced pathogenicity of APEC. These findings are highly significant for improving the understanding of the role of glycosyltransferases involved in APEC O-antigen synthesis.

[Objective] To elucidate the microbiological mechanisms and major pathways of gypsum as an amendment to reduce CH₄ emissions from saline-sodic paddy fields. [Methods] The saline-sodic wasteland was reclaimed as a paddy field, and four gypsum application treatments were set up: 0 t/hm² (CK), 15 t/hm² (G₁₅), 30 t/hm² (G₃₀), and 45 t/hm² (G₄₅), with three replications. The CH₄ emission fluxes were monitored by the closed static chamber method at the rice flowering stage, after which soil samples were collected from the tillage layer (0-15 cm) within the chamber area for metagenomic sequencing and soil physicochemical property analysis. [Results] The application of 15-45 t/hm² gypsum significantly reduced the CH₄ emission flux of saline-sodic paddy fields by 85.62%-92.64%, and the reduction amplitude increases with the increase of gypsum application rate. The dominant phyla of methanogens and methanotrophs of saline-sodic paddy soils did not change with the application of gypsum, and the relative abundance of hydrogenotrophic type of methanogens was as high as 90%. The relative abundance of Type Ⅱ methanotrophs increased by 50.00%-61.54% compared with that of the CK treatment after the gypsum application reached 30 t/hm². The alpha diversity index of both methanogens and methanotrophs increased with the increase of gypsum application rate, and the increase of the former was significantly smaller than that of the latter. Gypsum significantly decreased the relative abundance of the methanogenic functional gene torC, and increased the relative abundance of the methane oxidation functional genes pps, hdrD and rnfB. CO₃^2-+HCO₃^- and pH were the most important environmental factors of soil affecting the community structure of methanogens and methanotrophs. [Conclusion] The application of gypsum positively affected the community structure of methanogens and methanotrophs by reducing soil pH, but the negative effect of the community structure of methanotrophs on CH₄ emission flux outweighed the positive effect of the community structure of methanogens on CH₄ emission flux, thus reducing CH₄ emission. The results can provide a theoretical basis for the evaluation of ecological effects of agricultural development in saline-sodic land.

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] To explore the mechanism by which biochar alters the soil bacterial community structure and thereby affects the availability of soil phosphorus. [Methods] This study employed metagenomic techniques to investigate the soil bacterial communities and microbial functional genes involved in the phosphorus cycle after the application of biochar at different doses (CK: 0 kg/hm², T1: 300 kg/hm², T2: 600 kg/hm², and T3: 900 kg/hm²). [Results] The application of biochar significantly increased inorganic phosphorus, microbial biomass phosphorus, and alkaline phosphatase activity, which showed the increases of 21.75%, 699.39%, and 34.00%, respectively, under T2 treatment. Furthermore, the application of biochar changed the diversity and richness of soil microorganisms, especially bacteria, mainly enriching Actinobacteriota, Acidobacteria, Chloroflexota, Thermoproteota, Gemmatimonadota, Nocardioides, and Sphingobium. Soil pH, water content, organic matter, inorganic phosphorus, microbial biomass phosphorus, and available phosphorus were important factors influencing soil microbial communities. In addition, biochar significantly increased the abundance of the organic phosphorus mineralization-associated gene phoD, T2 increased by 9.28% compared with CK, and the abundance of phoD was significantly affected by total phosphorus, available phosphorus, and microbial biomass phosphorus content in the soil. [Conclusion] The application of biochar can enhance phosphorus availability by regulating soil bacterial community structure. The findings provide a theoretical basis for the application of biochar in improving phosphorus availability in farmland soil.

Currently, the drugs available for treating fungal infections show limited number and off-target effects. Thus, there is an urgent need to develop new antifungal drugs. Fungal apoptosis-like cell death (ALCD) is a cell death phenomenon that occurs during the normal development stage of organisms. This article summarizes the characteristics, signaling pathways, and key factors involved in fungal ALCD and introduces the natural and synthetic drugs that can induce fungal apoptosis. The natural drugs include lipid peptides, farnesol, statins, and alkaloids from microorganisms, organic acids and essential oils from plants, and melittins from insects. Furthermore, this article establishes the basic molecular landscape of drug-induced fungal ALCD. This article provides a theoretical basis for formulating a new strategy for resisting pathogenic fungi and developing targeted antifungal drugs.

[Objective] To understand the molecular functions and potential applications of the significantly up-regulated gene cluster chr1_2605-chr1_2604 in response to tetrabromobisphenol A (TBBPA) stress, we investigated the roles of chr1_2605 and chr1_2604 in the specific recognition and efficient degradation of TBBPA. [Methods] Synthetic biology methods were employed to construct Sphingobiumxenophagum C1 (pBBR-2605-HiBiT) and Escherichiacoli BL21(DE3, pET30b-2604) as chassis cells for biosensing and degrading, respectively. The response characteristics of Chr1_2605 in the chassis cells to different pollutants were analyzed by the luciferase activity assay. Additionally, the degradation activity of TBBPA by Chr1_2604 in the chassis cells was determined by high-performance liquid chromatography. [Results] The xenobiotic-responsive element Chr1_2605 exhibited a highly specific response to TBBPA. The Chr1_2605-based chassis cell of S. xenophagum C1 (pBBR-2605-HiBiT) demonstrated high responsivity and sensitivity to TBBPA, with a limit of detection ranging from 0.010 to 0.050 μmol/L. The 2-oxoglutarate/Fe-dependent dioxygenase Chr1_2604 in the chassis cell of E. coli BL21(DE3, pET30b-2604) displayed the degradation rate of 44.415% for 2.0 mg/L TBBPA within 3 d [0.296 mg/(L·d)], which was significantly higher than those of most reported microbial strains under non-co-metabolic conditions. [Conclusion] The chr1_2605-chr1_2604 gene cluster can accurately recognize and degrade TBBPA. Specifically, the xenobiotic-responsive element Chr1_2605 specifically recognizes TBBPA, whereas the 2-oxoglutarate/Fe-dependent dioxygenase Chr1_2604 efficiently degrades TBBPA.