[Objective] Ectomycorrhizal fungi can shape the bacterial community in the ectomycorrhizosphere, which represents an important way to mobilize and acquire insoluble mineral elements from the soil. This study aims to investigate the composition and phosphate-solubilizing characteristics of the dominant phosphate-solubilizing bacteria (PSB) in the ectomycorrhizosphere ofCastanea henryi. [Methods] The transparent halo method was employed to isolate PSB from the ectomycorrhizosphere ofC.henryi. The strains were identified by 16S rRNA gene sequencing. The degradation abilities of the strains for tricalcium phosphate (TCP) and apatite were studied by liquid fermentation. A scanning electron microscope and a X-ray diffractometer were used to observe the appearance and crystal structures of the degradation products. [Results] Five highly efficient strains of PSB were isolated from the ectomycorrhizosphere ofC.henryi. Strains LSCh1, LSCh2, and LSCh5 were identified asBurkholderia lata, and strains LSCh3 and LSCh4 were identified asParaburkholderia sp. The degradation abilities of the strains for TCP followed the trend of LSCh3 (556.94 mg/L) > LSCh2 (206.91 mg/L) > LSCh1 (170.83 mg/L) > LSCh5 (55.16 mg/L) > LSCh4 (14.21 mg/L). The degradation abilities of the strains for apatite were in a descending order of LSCh2 (51.33 mg/L) > LSCh1 (43.51 mg/L) > LSCh3 (40.99 mg/L) > LSCh5 (1.11 mg/L) > LSCh4 (1.00 mg/L). [Conclusion] Strain LSCh3 showed good performance in degrading both TCP and apatite and induced the formation of carbonates. It is a plant growth-promoting bacterium with potential application values in improving the phosphorus nutrients of plants and the quality of soil.

[Background] Yuncheng Salt Lake is a high-salt environment with intensive human activities. The community structure and ecological diversity of bacteria in Yuncheng Salt Lake are similar to those in other salt lakes while having their particularities. [Objective] Yuncheng Salt Lake is rich in color and harbors abundant halophilic and salt-tolerant microorganisms. To understand the distribution of bacterial resources in Yuncheng Salt Lake, we measured the bacterial diversity and community structures in different areas of this lake. [Methods] We employed 16S rRNA gene amplicon sequencing to study the community structures of halophiles in different areas of Yuncheng Salt Lake and predicted the potential metabolic functions of the bacteria. [Results] The dominant bacteria varied in different areas of Yuncheng Salt Lake. Specifically,Pseudomonadota,Actinobacteriota, andBacteroidota were dominant in the central lake,Bacillota in the eastern lake, andPatescibacteria in the western lake. The bacterial diversity in the central lake area with light yellow water was significantly higher than that in the eastern and western lake. However, the bacterial diversity was low in the central lake area with red water. This result indicated that the bacterial distribution was different in the central lake areas with different water colors the metabolic pathway activity of bacteria in the salt lake and strong regional distribution. The microbial metabolism in the east and west lake was more active than that in the lake. [Conclusion] Bacteria show high diversity in Yuncheng Salt Lake. The environment in different of lake influence the community structure of bacteria. This study provides a theoretical basis for the diversity conservation, development, and utilization of the bacterial resources in Yuncheng Salt Lake.

[Objective] To isolate efficient phosphorus-solubilizing strains from soils in the permafrost region of the Qinghai-Xizang Plateau and provide strain resources for the activation of unavailable phosphorus in the soil of the Plateau. [Methods] The selective media with organic and inorganic phosphorus were used to isolate phosphorus-solubilizing strains from the soil samples collected in the permafrost region around the Tanggula Pass of the Qinghai-Xizang Plateau by the plate streaking method. The phylogenetic tree was built based on the 16S rRNA gene sequences to identify the strains, and then the phosphorus-solubilizing abilities and stress tolerance of the strains were determined. [Results] Five strains belonging toPseudomonas were isolated, including three inorganic phosphorus-solubilizing strains (i5, i6, and i9L) and two organic phosphorus-solubilizing strains (Qb and Qo). After 7 days of incubation in shake flasks at 30 ℃, the content of available phosphorus in the supernatants of Qb and Qo was 534.8 mg/L and 723.7 mg/L, respectively, which was significantly higher than that (166.9–210.5 mg/L) in the supernatants of i5, i6, and i9L. The available phosphorus content in the supernatant of Qo was the highest (519.7–683.0 mg/L) among the five isolates under different concentrations of PEG6000. The phosphorus-solubilizing abilities of Qb and Qo were stronger than those of the other strains at 5 ℃ and 10 ℃. [Conclusion] Qo outperformed the other strains in terms of tolerance to low temperature and drought stress, serving the development of microbial fertilizers and vegetation restoration in alpine regions such as the Qinghai-Xizang Plateau.

[Objective] To investigate the effects of hydrogen peroxide treatment on the physicochemical properties and biogas production of lignite. [Methods] We carried out orthogonal experiments to optimize the conditions of hydrogen peroxide pretreatment for Shenli No.5 lignite. Lignite was treated under the optimal conditions to obtain coal residues and treatment solutions. The physicochemical properties, including elemental and maceral composition, mineral components, microcrystalline structure, porosity, permeability, surface morphology, organic functional groups, and organic composition in the treatment solution were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), brunauer-emmett-teller (BET), gas chromatography-mass spectrometry (GC-MS), and high-performance liquid chromatography (HPLC). The physicochemical properties were then compared among the raw coal, treated residue, and treatment solution. [Results] The optimal pretreatment conditions of lignite were treatment with 5.0% hydrogen peroxide at a liquid-to-solid ratio of 30:1 for 20 days, under which the total organic carbon yield in the treatment solution was 105 mg/L. After treatment under these optimal conditions, the treated residue exhibited increased cracks and dents on the surface and loosened surface structures. In addition, the interlayer spacing of the aromatic plains of the coal increased while the aromatic ring structure became more open with smaller crystal nucleus structures. Both porosity and specific surface area increased after the treatment. Compared with that before treatment, the treated residue showcased decreased fixed carbon, carbon, and vitrinite and increased ash, volatile matter, oxygen and hydrogen, and inertinite. The content of functional groups such as O=C−O, C=C, and C=O increased in the treated residue, while that of N−H and C−H reduced. The biogas production of the treatment solution and the treated residue was 39.13% and 94.46%, respectively, lower than that of raw coal. Hydrogen peroxide pretreatment primarily acted on vitrinite, dissolving organic carbon and altering the functional groups of large molecular structures in coal. This altered the aromatic ring structure of coal, causing small molecules to dissolve into the treatment solution under oxidative conditions. The organic compounds in the treatment solution mainly consisted of short-chain fatty acids. After biogas production, the number of low-molecule-weight acids and organic compounds decreased in the treatment solution. The relative abundance of dominant microbial phyla and genera varied significantly among different microcosms. Regarding the archaea for biogas production, the dominant phylum and genus wereHalobacteriota andMethanosarcina in the raw coal andThermoproteota andBathyarchaeia in the treatment solution, respectively. In terms of the bacteria for biogas production, the dominant phylum and genus wereActinomycetota andGaiellales in the raw coal andPseudomonadota andDelftia in the treatment solution, respectively. [Conclusion] The organic carbon dissolved from coal can be utilized by microorganisms for biogas production. However, the removal of organic components by over-oxidation may decrease the biogas production.

[Objective] To study the variations of soil fungal diversity in the coal mine residue hills with vegetation restored for different years. [Methods] We selected the soil on the coal mine reside hills of Jiangcang Mine with different planting years (2, 4, and 6 years) as the research object, measured the soil chemical property and enzyme activity, and used high-throughput sequencing methods to measure the soil fungal diversity. [Results] As the duration of restoration increased, significant differences were observed in soil pH, total potassium, and organic matter. The activities of enzymes such as sucrase, urease, catalase, and phosphatase gradually increased, which enhanced the fungal richness and diversity in soil. The variations were more obvious after four years of restoration. The fungi were primarily dominated byAscomycota andBasidiomycota, with saprophytic fungi accounting for 43.2%–89.7%. Nitrogen content and soil enzyme activity were the key factors influencing fungal diversity in the grasslands of the coal mine area in Jiangcang. [Conclusion] Vegetation restoration can improve the chemical properties and fungal diversity in soil.

[Objective] Bio-inspired artificial mineral shells are used to protect living bacterial cells. [Methods] Bacterial cells were encapsulated in firm and intact mineral shells, where the limited physical space and substance exchange induced the dormancy of living bacteria to decrease the viability loss during long-term preservation and even in extreme environments. Moreover, acids can erode the shells to reactivate the bacteria. [Results] Compared with the un-mineralization treatment (EcN), the mineralization treatment (EcN@CaCO₃) increased the bacterial viability by a maximum of 262 folds in a 32-day storage experiment and the survival rate by 837, 171, 59.1, and 729.7 folds at pH 2.5, pH 12.0, 80 ℃, and in the presence of an antibiotic, respectively. [Conclusion] We employed biomimetic mineralization to improve the stability of bacterial cells in storage, which can provide a research basis for the application of microorganisms in environmental engineering, food production, and biomedical engineering.

[Objective] To study the effect of hydrogen peroxide (H₂O₂) treatment on biogas production of vitrinite from coal. [Methods] Shengli lignite collected from Inner Mongolia was used in this study. The methanogenic microbial consortium previously enriched and preserved in our laboratory was used as the inoculum. Coal macerals were separated by floatation, which yielded three samples containing high vitrinite (GJ), medium vitrinite (ZJ), and low vitrinite (DJ). After being characterized, the samples were treated with 10% H₂O₂ for 30 days at a solid-to-liquid ratio of 1:15. Biogas production experiments were conducted with the coal samples before and after treatment. Gas chromatography was employed to analyze the gas composition, and X-ray diffractometry and Fourier transform infrared spectroscopy were employed to study the physical and chemical properties of the coal before and after treatment as well as after gas production. [Results] The coal samples after H₂O₂ treatment showcased reduced vitrinite content and carbon fixation and increased volatile matter. The reaction was more intense in the coal sample with high content of vitrinite, accompanied by increased oxygen content and reduced carbon. Methane yields from untreated coal samples on day 100 followed the order of GJ (174.24 μmol/g coal)>ZJ (164.31 μmol/g coal)>DJ (135.52 μmol/g coal). However, the coal samples pretreated with H₂O₂ ceased gas production after day 20, with the gas yields of 39.63, 39.61, and 41.55 μmol/g coal, respectively, representing reductions of 77.26%, 75.89%, and 69.34%, respectively, compared with those from the coal samples without treatment. Furthermore, as vitrinite content increased, the coal samples demonstrated decreased layer spacing (d₀₀₂) of the aromatic ring lamellae, ductility (L_a) of the single-layer lamellae, and stacking degree (L_c) of the lamellae and increased number of aromatic layers (N) after H₂O₂ treatment, which indicated that the crystal nuclei appeared smaller. In addition, H₂O₂ treatment led to increased proportions of aromatic carbons, aromatic moieties, C=O groups, and C=C groups, enhanced aromatic ring condensation, and increased number of oxygen-containing functional groups. [Conclusion] Long-term H₂O₂ treatment reduces organic matter that is readily bioavailable in coal matrix, thereby decreasing gas production.

[Objective] The biofloc-based culture system (BFS) ofPenaeus vannamei is a new ecological shrimp production mode based on the concept of cultivating and regulating the microbial community in the aquaculture system. However, the characteristics and assembly processes of microbial communities in different habitats of the BFS remain unclear. [Methods] The 16S rRNA gene sequencing was employed to explore the bacterial community composition in three different habitats (water, bioflocs, and shrimp gut) of the BFS. SourceTracker and the neutral model were adopted to explore the characteristics and assembly processes of bacterial communities in different habitats. [Results] The bacterial community diversity and composition varied significantly in the three habitats, and the structures and composition of bacterial communities were similar between bioflocs and shrimp gut. SourceTracker results showed that 98.76% of bacterial taxa in the shrimp gut were sourced from bioflocs, and only 0.83% were derived from water.Ruegeria existed in all the three habitats, with the relative abundance of 1.72%, 7.34%, and 6.00% in water, bioflocs, and shrimp gut, respectively. The unique amplicon sequence variants (ASVs) showed the maximal number of 89 in water, mainly belonging toMariculis andOwenweeksia. Bioflocs contained 56 ASVs, which were mainlyRheinheimera. Only 10 ASVs were present in the shrimp gut, mainly belonging toRoseobacter. The bacterial communities in water, bioflocs, and shrimp gut were all fit to the neutral model, which indicated that the bacterial communities in the three habitats were dominated by the neutral process. [Conclusion] The microbial communities in different habitats of the BFS were significantly different, and the intestinal bacteria of shrimp mainly came from bioflocs. The assembly processes in the three habitats were dominated by neutral processes. The results provide a theoretical basis for regulating the microbial community in the BFS.

Listeria monocytogenes, a major zoonotic food-borne intracellular pathogen, is ubiquitous in the natural environment and easily contaminates animal-derived food products. The consumption of the contaminated food can cause severe listeriosis in both humans and animals, with the mortality rate reaching up to 30%. The antimicrobial therapy is the only feasible approach for treatingL.monocytogenes infection sinceL.monocytogenes is susceptible to multiple antimicrobials. However, the reports of multidrug-resistant strains are increasing due to the selective pressure exerted by the irrational use of antimicrobials or disinfectants. The antimicrobial resistance mechanisms ofL.monocytogenes are complex. Efflux pump proteins are crucial in bacteria and participate in various biological processes. Specifically, they can influence bacterial sensitivity to antibiotics, facilitate the efflux of toxic compounds, and affect bacterial virulence. Over the last two decades, scholars have conducted research on the efflux pumps-mediated resistance ofL.monocytogenes, identifying several efflux pump proteins associated with the efflux of antibiotics or toxic compounds. Additionally, some efflux pumps are involved in the virulence expression process ofL.monocytogenes. This paper reviews the research advances in the functions and regulatory mechanisms of efflux pumps in multidrug-resistantL.monocytogenes. It provides a theoretical foundation for probing into the environmental adaption mechanisms ofL.monocytogenes, curbing the spread of this pathogen, and identifying new drug targets for combating infections.

[Objective] To investigate the diversity of bacteria and fungi in the pathosphere ofPlasmopara viticola and screen out the strains with potential biocontrol effects on grape downy mildew. [Methods] The leaves infected byP.viticola were collected from seven representative grape-producing regions in northern and southern China in two consecutive years. The collected leaves were cultured in a humid environment, and the newly growing downy mildew was aseptically picked by forceps to prepare the sporangial suspensions ofP.viticola. The strains were isolated by the conventional culture method and identified based on the morphological characteristics, BOX-PCR fingerprints, and molecular sequences. Furthermore, the clustering analysis of different strains was conducted. Sporangial inhibition was tested with equal volumes of strain suspension or fermentation mixed with the sporangial suspension ofP.viticola, and the control effects of isolates and their sterile fermentation against grape downy mildew were tested on detached grape leaves. [Results] A total of 90 bacterial strains and 110 fungal strains were isolated, belonging to eight bacterial genera and 14 fungal genera, respectively. The pathosphere ofP.viticola in the same province and the same year exhibited similar microbial community composition. Notably, strains ofPseudomonas spp. andCladosporium spp. exhibited stable populations on grape cultivars collected from different provinces. A majority (over 80.0%) of strains with stable populations in two consecutive years demonstrated significant biocontrol effects against grape downy mildew. SixAcremonium strains with ubiquitous distribution demonstrated the biocontrol effect up to 100.0%. Sterile fermentation of the fungal strainsAspergillus niger NX2F,Thecaphora amaranthi BJ1G, andRhizopus stolonifer BM1L showed the control effects of 100.0% against grape downy mildew. [Conclusion] The culturable bacterial and fungal communities in the pathosphere ofP.viticola were mainly affected by geographical factors in different provinces, and most of the culturable microorganisms presented stable and strong biocontrol effects on grape downy mildew. To the best of our knowledge, it is the first comprehensive report thatAcremonium spp. were epibiotic fungi and consistently associated withP.viticola, providing rich and valuable biocontrol resources for grape downy mildew.