Lactic acid bacteria (LAB) are the predominant probiotics with significant health-promoting potential. Xizang pigs, an invaluable indigenous breed in China, harbor a unique and largely unexplored reservoir of intestinal LAB. [Objective] To screen high-quality LAB isolated from Xizang pigs. [Methods] LAB were isolated by the streak plate method and identified by 16S rRNA gene sequencing. Two Limosilactobacillus reuteri strains with significantly different lactic acid production capacities were selected from Xizang pigs. The two strains, together with one L. reuteri strain previously preserved in our laboratory, which originated from duroc×landrace×yorkshire pigs, were assessed in terms of acid and bile salt tolerance, antioxidant activity, antibacterial properties, and antibiotic resistance. [Results] A total of 21 LAB strains were isolated and identified from the intestinal microbiota of Xizang pigs, including ten Streptococcus alactolyticus strains, six L. reuteri strains, three Lactobacillus amylovorus strains, one Leuconostoc mesenteroides strain, and one Limosilactobacillus vaginalis strain. Among the three strains screened out, L. reuteri T-B5L2 exhibited the highest lactic acid production. Moreover, this strain demonstrated strong survival under pH 3.0 and 0.1% bile salts. L. reuteri T-B5L2 exhibited the strongest inhibitory activity against enteropathogenic Escherichia coli and Salmonella Choleraesuis. There were no significant differences in antioxidant activity among the three strains. All the three strains exhibited high sensitivity to penicillins and cephalosporins but displayed resistance to tetracyclines, aminoglycosides, and glycopeptides. [Conclusion] In this study, 21 LAB strains were isolated from the feces of Xizang pigs, among which L. reuteri T-B5L2 exhibited the highest acid production capacity. Further in vitro biochemical characterization demonstrated that this strain exhibited good growth performance, acid and bile salt tolerance, antioxidant activity, and the ability to inhibit pathogenic bacteria. These findings suggest that L. reuteri T-B5L2 is a promising probiotic candidate with potential applications in improving intestinal health and mitigating pathogenic infections.

[Objective] Conventional culture methods can merely uncover a fraction of microbial diversity. A vast number of microorganisms remain unculturable under laboratory settings. The advent of in-situ culture technology offers a key solution to this predicament. This study endeavors to innovate the in-situ culture technology, explore microorganisms under hitherto unknown culture conditions, and probe into their potential applications within the realm of uncultured microorganisms. [Methods] PCR tubes were employed as the core of the device, and the idea of sorting prior to culture was introduced. Microorganisms were separated from the environment by means of polymer membranes for independent culture. The efficacy of the device was validated through the pure culture of Escherichia coli. Moreover, this device was applied to in-situ culture in diverse environments such as soil, sewage, and mountain spring water. [Results] The abundance of E. coli increased significantly in the pure-culture device. When the concentration of the polymer membrane reached 15%, the encapsulation effect effectively prevented the escape of E. coli. The co-culture experiments further corroborated this finding. In the in-situ culture experiments, the device designed in this study successfully cultured single-cell microorganisms from sewage, soil, and mountain spring water samples. Sequencing results indicated that this device could culture species recalcitrant to be cultured in the laboratory. Comparison with the NCBI database verified that new species were successfully cultured, which demonstrated the effectiveness of the culture device in various environments. [Conclusion] The culture method designed in this study is suitable for single-cell microbial culture, enrichment of specific microbial communities, and co-culture of multiple microorganisms. The device can isolate and culture richer and more microorganisms than conventional culture methods. This new technology not only isolates and cultures more microorganisms but also manages to culture those previously unculturable under laboratory conditions. It holds great significance for microbiological and ecological research.

Allergic asthma is a prevalent chronic inflammatory disease characterized by airway hyperresponsiveness and airway inflammation, often triggered by inhalant allergens such as pet dander and pollen. [Objective] Studies have revealed that helper T cells (Th cells) play a crucial role in the immune regulation of allergic asthma. Particularly, Th2 cells exacerbate airway inflammation by secreting cytokines such as interleukin (IL)-4 and IL-5, which promote the proliferation of eosinophils and mast cells. Additionally, the activation of Th17 cells is closely related to the inflammatory response in allergic asthma. Therefore, modulating the balance of Th1/Th2 and Th17/Treg cells has become an effective strategy for treating allergic asthma. This study explores the pathogenesis of allergic asthma and novel therapeutic approaches. [Methods] We constructed an engineered bacterium EcN ^canf-1 specifically expressing the dog allergen Canf-1. Using the pBAD promoter, we controlled the expression of Canf-1 in the lungs of mice. [Results] EcN ^canf-1 exerted immunomodulatory effects by regulating pulmonary cytokine expression profiles, specifically downregulating the expression of pro-inflammatory cytokines including IL-6, IL-5, and IL-13, while upregulating the expression of anti-inflammatory mediators such as interferon-γ (IFN-γ), transforming growth factor-β (TGF-β), and IL-10, thus alleviating allergic symptoms in the lungs. EcN ^canf-1 demonstrated remarkable efficacy in suppressing the pathological overexpression of Th2 and Th17 lymphocyte subsets under allergic conditions, while enhancing the functions of Th1 and regulatory T cells. Furthermore, EcN ^canf-1 significantly reduced pulmonary mast cell infiltration, attenuated vascular permeability, and mitigated allergen-induced hypothermia and airway constriction. These findings demonstrated that EcN ^canf-1 played a pivotal role in immune homeostasis regulation and represented a promising therapeutic candidate for allergic pulmonary inflammation through its multifaceted modulation of immunological pathways. [Conclusion] EcN ^canf-1 provides a new therapeutic avenue for allergic asthma by modulating the expression of immune cells and cytokines. This not only offers new insights into the immune mechanisms of allergic asthma but also provides a scientific basis for the development of new targeted biological treatment strategies.

Coastal wetlands, among the most productive ecosystems on Earth, are situated at the interface between land and ocean, receiving substantial nitrogen inputs. These ecosystems exhibit active nitrogen cycling and play a crucial role in global nitrogen budgets and climate regulation. Archaea constitute a critical component of the microbial communities in coastal wetlands, yet their ecological significance was overlooked. The advancements in novel biological technologies have unveiled the diversity and ecological functions of archaea, highlighting their significant contributions to nitrogen cycling. This review summarizes the distribution and diversity of archaea in coastal wetland ecosystems, with a particular focus on their roles in key nitrogen cycling processes such as nitrogen fixation, nitrification, denitrification, and nitrate ammonification. In addition, for the application of archaea in global climate change mitigation, we explore the idea of using archaeal communities to reduce nitrous oxide emissions from coastal wetlands.

The wastewater containing petroleum hydrocarbons is mainly produced in the process of petroleum exploitation and petroleum products processing. It encompasses the water polluted by leakage in oil exploitation, the wastewater produced in machining, and the wastewater produced using auxiliaries in leather printing and dyeing. The wastewater containing petroleum hydrocarbons has high organic matter content, high toxicity, and poor biodegradability. Biodegradation has become one of the main research hotspots of the treatment of wastewater containing petroleum hydrocarbons because of no secondary pollution. Based on the latest literature and our research results, this paper details the composition of wastewater containing petroleum hydrocarbon, microbial species for biodegradation, biodegradation mechanism, biochar immobilization and remediation technology, and degradation genes and enzymes. This paper can provide reference for the further study of microbial flora degradation of wastewater containing petroleum hydrocarbon.

Microplastics are novel pollutants that are widespread in the oceans, soil, and atmosphere, affecting the process of pollutant transport and transformation through physical, chemical or biological interactions. The heavy metal pollution caused by mining activities in the soil and water environment around antimony mining regions is increasing year by year. However, the effect of microplastics on the biogeochemical transformation of heavy metal contaminants in the mining regions has been rarely reported. [Objective] To understand the effects of microplastic type, size and concentration on microbially mediated antimony release from stibnite. [Methods] We took Pseudomonas sp. J-1 with strong antimony tolerance and promoting antimony release and widely used polypropylene, polyvinyl chloride, and polystyrene as the objects of the study. The changes in pH, redox potential (ORP), microbial biomass, and antimony concentration were analyzed. Furthermore, microplastic adsorption of antimony under different pH values was studied, and confocal laser scanning microscopy (CLSM) and scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS) were employed to reveal the mechanism by which microplastics affected the biogeochemical cycle of antimony. [Results] Polypropylene with a particle size of 13 μm and a high concentration had the strongest inhibitory effect on stibnite dissolution with the participation of Pseudomonas sp. J-1. Microplastics inhibited the growth of the bacterial colony, which led to weakened promoting effect on the release of antimony, and the growth of Pseudomonas sp. J-1 was even completely inhibited by the high concentration of microplastics. Microplastics were able to adsorb antimony, while the adsorption capacity was independent of solution pH. [Conclusion] The type, particle size, and concentration of microplastics are the key factors affecting the stibnite dissolution mediated by Pseudomonas sp. J-1 and they indirectly affect stibnite dissolution mainly by influencing microbial growth.

[Objective] To study the mechanisms of mutual promotion between chemolithoauto-trophic sulfur-oxidizing bacteria and chemoheterotrophic bacteria under co-culture based on carbon metabolism. [Methods] Ion chromatography was employed to determine the concentrations of S₂O₃^2‒ (thiosulfate) and SO₄^2‒ (sulfate). Bacterial growth dynamics were monitored by the dilution plate method. Extracellular carbon characteristics were analyzed via total organic carbon analyzer measurement and LC-MS. Cellular morphology was observed by scanning electron microscopy. The relative mRNA levels of related genes were quantified by RT-qPCR. [Results] During the growth process, sulfur-oxidizing bacteria continuously fixed inorganic carbon and secreted organics, providing a stable carbon source for the growth of heterotrophic bacterium. In return, heterotrophic bacteria significantly enhanced the sulfur-oxidizing and carbon-fixing capabilities of sulfur-oxidizing bacteria. This was evidenced by the significantly up-regulated expression of the enzyme gene soxB involved in sulfur oxidation and the RubisCO gene cbbL involved in carbon fixation. Additionally, the production of extracellular polymeric substances was induced, which enhanced the biofilm formation. [Conclusion] This study elucidated the interaction mechanisms between sulfur-oxidizing bacteria and heterotrophic bacteria, particularly the significant enhancement of the carbon-fixing capability of sulfur-oxidizing bacteria. The findings provide a new perspective for the enrichment culture of chemolithoautotrophic bacteria and for understanding the carbon fixation mechanisms of autotrophic sulfur-oxidizing bacteria in microbial communities. Additionally, this study offers theoretical support for the low-carbon and efficient treatment of wastewater.

[Objective] To investigate the bio-weathering effects and mechanisms of Acidithiobacillus ferrooxidans on granite under acidic conditions (pH 2.0). [Methods] A 36-day immersion experiment was conducted, comparing the microbial group, acid solution group (pH 2.0, H₂SO₄), and pure culture medium (control) group. Physicochemical parameters [pH, redox potential (Eh), and electrical conductivity (EC)] of the soultion, surface chromaticity (CIE-Lab) of granite, and mineral dissolution characteristics were analyzed. [Results] The microbial group significantly accelerated granite weathering, forming a distinct weathered layer on the surface after 9 days. During the initial phase (0‒3 days), plagioclase dissolution caused a pH increase followed by stabilization. Fe³⁺ accumulation-dominated Eh and EC were regulated by both the initial ion background and weathering products. After bio-weathering, the granite exhibited a decrease of 11.6 in L* (reduced brightness), an increase of 6.8 in a* value (enhanced reddish-brown tone), and an increase of 9.6 in b* value (increased bluish tone). Surface reddish-brown areas were directly correlated with jarosite deposition. [Conclusion] Under acidic conditions, A. ferrooxidans accelerate granite weathering via Fe³⁺-mediated redox reactions. The chromaticity parameters (ΔL*, Δa*, and Δb*) and morphological characteristics serve as indicators for rapidly assessing weathering intensity. These findings provide a novel basis for evaluating weathering risks caused by acid mine wastewater in surrounding rocks and guiding ecological remediation.

[Objective] To study changes of the bacterial community structure in the Second Drainage Ditch in Ningxia after ecological engineering. [Methods] We employed high-throughput sequencing to study the bacterial community structures in water samples. We explored the factors affecting the bacterial community structure by non-metric multidimensional scaling (NMDS) and redundancy analysis (RDA). [Results] From August 2021 to August 2022, the ammonium nitrogen, total nitrogen (TN), permanganate index, dichromate oxidizability (COD_Cr), and fluoride in the water decreased substantially after the ecological engineering. The dominant bacterial phyla in the water were Proteobacteria, Actinobacteria, Bacteroidetes, and Chloroflexi and the dominant genera included hgcI_clade, SAR11_cladeIII, Limnohabitans, Rhodoferax, and Flavobacterium. The bacterial community structures showed significant differences across different sampling locations. The NMDS results revealed significant variations in the bacterial community structure across different sampling months. The RDA results indicated that total phosphorus (TP), COD_Cr, and pH were the key factors influencing the bacterial community structure. Notably, TP, COD_Cr, and TN together explained the largest variance (8.81%) in the bacterial community structure, followed by TP combined with COD_Cr (-8.05%). [Conclusion] After ecological engineering, the water quality of the Second Drainage Ditch improved, and the bacterial community structure became more diverse. The physicochemical properties of the water strongly influence the distribution and diversity of bacterial communities in the Second Drainage Ditch in Ningxia, which provide a scientific basis for managing the regional water environment.