The thioredoxin family plays crucial roles in bacterial oxidative stress defenses and virulence regulation, while the function of its member YbbN in Vibrio parahaemolyticus remains unclear. [Objective] To elucidate the regulatory role of YbbN in the biological characteristics and pathogenicity of Vibrio parahaemolyticus, providing potential targets for developing novel anti-infection strategies. [Methods] The ybbN knockout strain (ΔybbN) and complementary strain (CΔybbN) of Vibrio parahaemolyticus SH112 were constructed by homologous recombination. The strains were compared regarding the growth characteristics, motility, biofilm formation, bacterial competition, cell adhesion, cytotoxicity, and pathogenicity in mice. [Results] Although the knockout of ybbN showed no significant effects on bacterial growth, motility, cell adhesion, or colonization, it markedly attenuated key pathogenic traits. Specifically, it decreased the biofilm formation (by 19%-30%), killing efficiency against competitive bacteria (*: P<0.05; ****: P<0.000 1), and cytotoxicity in HeLa cells (by 27%), while increasing the survival rate of mice by 87.5%. [Conclusion] This study demonstrates for the first time that YbbN specifically regulates critical aspects involved in biofilm formation, bacterial competition, and cytotoxicity in host cells, significantly influencing the biological characteristics and pathogenicity of Vibrio parahaemolyticus. These findings not only expand the understanding about the functional diversity of the thioredoxin family proteins but also provide new molecular targets and a theoretical basis for preventing Vibrio parahaemolyticus infections.

[Objective] To construct a strain XH02Δlpxtg270 with knockout of the LPXTG motif protein-coding gene from Corynebacterium pseudotuberculosis XH02 and explore the role of lpxtg270 in the growth, biofilm formation, and infection of XH02. [Methods] CRISPR/Cas9 was employed to construct XH02Δlpxtg270. The knockout strain and the wild strain XH02 were compared in terms of biological characteristics, invasion into J774A.1 macrophages, and pathogenicity in mice. [Results] Compared with XH02, XH02Δlpxtg270 did not change significantly in the colony morphology, growth curve, adhesion to J774A.1 macrophages, or intracellular proliferation, while it demonstrated reductions in the biofilm formation and invasion into J774 A.1 cells. Moreover, the release of lactate dehydrogenase and secretion of interleukin-1β from J774 A.1 cells infected with the knockout strain decreased compared with those infected with the wild strain. Compared with XH02, XH02Δlpxtg270 showed weakened pathogenicity in mice and decreased loads in the liver, spleen, kidney, lung, and brain, causing milder pathological changes of above organs in mice. [Conclusion] LPXTG270 of C. pseudotuberculosis is related to the biofilm formation and invasion into macrophages, playing a key role in the pathogenicity of this bacterium in mice.

Currently, the sustainable development of global agriculture is facing multiple challenges, including soil degradation, resource constraints, and environmental pollution. With the continuous growth of the population and the increasing demand for food quality, improving soil health has become a crucial foundation for ensuring food security. Although chemical fertilizers play an important role in maintaining the high yields and high quality of plants, their excessive or unreasonable use can cause environmental problems, such as soil acidification and water eutrophication. Rhizosphere microbial communities play an essential role in plant nutrient acquisition, tolerance to environmental stress, and adaptation to environmental changes. Among them, synthetic microbial communities (SynComs) are designed via the targeted assembly of multiple microorganisms with well-defined functions and clear genetic backgrounds, enabling the achievement of complex functionalities that cannot be accomplished by single strains. They are powerful tools for deciphering the key interface interaction mechanisms among plants, soil, and microorganisms and play a vital role in promoting efficient utilization of plant nutrients, enhancing plant stress resistance, and increasing the efficiency and reducing the application of fertilizers. This study reviews the conceptual evolution, current research trends, and construction principles, methods, and tools of SynComs, and summarizes the role of SynComs in the sustainable development of agriculture from the aspects of promoting plant growth, inhibiting biotic and abiotic stresses, and improving and restoring soil health. Furthermore, this paper makes an outlook on the future research directions and emphasizes the research and development of targeted microbial agents, the application of artificial intelligence (AI) in community assembly, and the performance improvement of SynComs in field applications, aiming to support the coordinated and multi-objective development of food security, efficient resource utilization, and environmental protection through near-natural microbial means, thereby facilitating the green agricultural development of China.

[Objective] To compare the bacterial growth, oxidative resistance, and bacterial infection in cells and host among Listeria monocytogenes EGD-e, lmo0175 (LPXTG motif-anchored protein)-deleted and complementary strains, so as to investigate the roles of Lmo0175 in anti-oxidative resistance and bacterial infection. [Methods] The lmo0175-deleted and complementary strains were constructed to compare the difference in bacterial growth, oxidative resistance, adhesion, invasion, intracellular proliferation, survival of infected mice, and bacterial loads in organs of Listeria monocytogenes. [Results] The deletion of lmo0175 remarkably decreased oxidative resistance, cell proliferation, colonization in the liver and spleen, and pathogenicity in mice. However, it had no significant impact on bacterial growth, adhesion or invasion. [Conclusion] The LPXTG motif-anchored protein Lmo0175 contributes to the anti-oxidative resistance, proliferation, and colonization in specific organs of Listeria monocytogenes.

Lipases are a group of biocatalysts that efficiently catalyze the hydrolysis, alcoholysis, acidolysis, ester exchange, and synthesis of esters at the oil-water interface. These enzymes play crucial roles in various fields, including pharmaceuticals and chemical engineering. Microbial lipases are more readily available and hold greater value for research and application than animal and plant lipases. [Objective] To isolate lipase-producing microorganisms from natural environments, optimize their culture conditions, and characterize the structure of the produced lipase. [Methods] We used bromocresol purple as an indicator to screen lipase-producing strains from oil-contaminated soil and identified the strains by morphological observation and 18S rRNA gene sequencing. We optimized the culture conditions of the strains by single-factor experiments and response surface methodology. We performed proteomic sequencing on the active proteins to identify the potential lipase. We amplified and sequenced the gene of the potential lipase by PCR and analyzed its multi-level structure. [Results] A lipase-producing fungal strain FA3 was isolated from oil-contaminated soil and identified as Aspergillus sp. The strain was cultured with olive oil as the sole carbon source, and the p-nitrophenol colorimetric method revealed that the intracellular enzyme activity of strain FA3 was 263.75 U/g. The optimized culture conditions were as follows: emulsified olive oil at 4 mL/L, peptone at 18 g/L, K₂HPO₄ at 1 g/L, NaCl at 10 g/L, MgSO₄ at 0.5 mmol/L, and pH 5.3. After culture at 30 ℃ for 77.5 h, the specific activity reached 2 120.27 U/g, which was about 8.04 times higher than that before optimization. The proteomic analysis and structural prediction revealed the conserved Gly-Asp-Ser motif, confirming the lipase as a typical GDSL lipase. The enzyme contained strictly conserved Ser, Gly, Asn, and His residues and it was thus classified as a member of the N-sulphoglucosamine sulphohydrolase (SGNH) hydrolase family. [Conclusion] After optimization of the culture conditions, strain FA3 demonstrated significantly enhanced lipase production, showing great potential for application. We clarify the functions and structural characteristics of the lipase, providing a basis for the engineering of related proteins.

Alcoholic liver disease (ALD) is a liver disease caused by long-term excessive alcohol consumption and is one of the most common chronic liver diseases worldwide. At present, no effective approach is available for preventing or reversing this disease, causing a serious social burden and increasing the pressure for prevention and treatment. In recent years, researchers have found that long-term alcohol abuse can lead to significant changes in the structure and function of the gut microbiota, thereby disrupting the balance of the gut microbiota, which can promote the progression of ALD. Therefore, maintaining gut microbiota balance can provide new targets for the prevention and treatment of ALD. This article reviews the research and intervention progress of the gut microbiota and its metabolites in ALD in recent years, providing reference for future studies on the pathogenesis and treatment of this disease.

Candida auris, as a multidrug-resistant fungus, pose a challenge to clinical treatment because of biofilm formation. Currently, effective intervention measures against its biofilm remain to be developed. [Objective] To explore the antifungal activity and biofilm inhibition mechanism of the Chinese medicine active compound matrine (MT) against C. auris. [Methods] The minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), and sessile minimum inhibitory concentration (SMIC) of MT against C. auris were determined by the microdilution method. The time-growth curve and colony morphology of C. auris under the intervention of MT were observed by the plate method. The changes in the hydrolytic enzyme activity of the C. auris biofilm treated with MT were determined. The changes in cell surface hydrophobicity (CSH) of C. auris biofilm treated with MT were observed by the water-hydrocarbon two-phase method. The effects of MT on the metabolic activity and structure of C. auris biofilms were observed by the XTT method, crystal violet method, and confocal laser scanning microscopy (CLSM). The changes in the cell nucleus of C. auris in the biofilm treated with MT were detected by DAPI staining. The protective effect of MT on the host infected with C. auris was observed by the Galleria mellonella larvae infection model. [Results] The MIC of MT against C. auris was 128 μg/mL, while the MFC and SMIC were both 512 μg/mL. The inhibition mechanism of MT against the proliferation of C. auris mainly involved reducing the CSH, inhibiting the mature biofilm formation, significantly decreasing the metabolic activity, and inducing abnormal nuclear morphology. The experiments with G. mellonella larvae further confirmed that MT could alleviate the invasive damage caused by C. auris. [Conclusion] MT has a significant antifungal effect on C. auris and can effectively inhibit the biofilm formation, providing a new candidate drug and potential target for clinical treatment of multidrug-resistant C. auris infections.

Colorectal cancer (CRC) remains a focal point of research due to its consistently high incidence and mortality, as well as the substantial economic and healthcare burdens it imposes. In recent years, the pivotal role of the gut microbiota in the prevention, diagnosis, and treatment of CRC has garnered increasing attention, offering promising avenues for the management of advanced stages of the disease. This article comprehensively reviews the involvement of the gut microbiota in the development and progression of CRC, elucidating the underlying mechanisms. Furthermore, it examines the potential applications of the gut microbiota in the systemic treatment of advanced CRC, with the aim of proposing novel strategies and insights to enhance the diagnosis and treatment of advanced CRC.

Root-knot nematode, among the most destructive plant-parasitic nematodes, poses a severe threat to global agricultural production. The plant root microbiome is considered as the “second genome” of host plant and plays an indispensable role in plant growth, development, and stress response. Parasitism by root-knot nematode significantly disrupts the community structure and function of root-associated microbial communities in plants. The disturbance of host microbiome not only exacerbates plant pathological processes but also may induce cascade effects through tripartite interactions among microorganism, plant, and nematode. This review comprehensively elucidates the multifaceted impacts of root-knot nematode parasitism on the root micro-ecosystem of host plant, particularly focusing on the variation in the structural and functional characteristics of both the rhizosphere and endophytic microbiome, as well as their roles in the occurrence of nematode diseases and maintaining plant health. Investigating the interaction between pathogenic nematodes and plant microbiome on community level will not only advance our understanding the intricate network among plant, nematode, and microorganism, but also provide theoretical and practical insights for developing innovative strategies for controlling plant nematode diseases.

[Objective] To explore the effects of plant diversity and soil improvement on the soil microbial community in abandoned lead-zinc mine wasteland. [Methods] A pot experiment was conducted with nine commonly used plants for ecological restoration in mining areas. Different plant diversity levels (S1 to S5) were set up, and for each level, a control group (Y: without soil amendment) and an improvement group (G: with organic fertilizer and polyacrylamide) were established. [Results] The plant height of the improvement group was generally higher than that of the control group. After soil improvement, the content of available nitrogen, available phosphorus, and available potassium all significantly increased, while that of heavy metals Cd and Pb decreased the most when the species richness was 9 (S5), dropping by 37.20% and 14.85% respectively. The diversity of soil microorganisms increased with the increase in plant diversity. The application of soil amendments reduced the richness and diversity of the fungal community, while enhancing the richness and diversity of the bacterial community. In the improvement group, the soil fungal abundance reached the highest level when GS4 configuration was adopted, with the Observed index and Chao1 index being 110.50 and 169.23, respectively. The soil bacterial abundance reached the highest level when GS2 was adopted, with the Observed index and Chao1 index being 1 081.59 and 1 116.79, respectively. In the fungal community, the abundance ofascomycetesat both the phylum and genus levels increased to varying degrees in the improvement group compared with the control group, and the abundance of Ascomycota increased with the increase in plant diversity. Soil improvement reduced the abundance of Mucoromycota and Rhizopus, but increased the abundance of Sordaria. Moreover, the abundance of Mucoromycota and Rhizopus decreased with the increase in plant diversity. In the bacterial community, soil improvement increased the abundance of Sphingomonas and Gemmatimonas. [Conclusion] Soil microbial diversity increases as the plant diversity increases. The application of soil amendments reduces the richness and diversity of soil fungi and improves the richness and diversity of soil bacteria. As the plant diversity increases, the abundance of Ascomycota increases, while that of Mucoromycota and Rhizopus decreases.