Equine coronavirus (ECoV) is an emerging virus attacking the gastrointestinal tract in horses, and the infected adult horses mainly present fever, abdominal pain, and diarrhea. In 1975, ECoV infection first appeared in the United States, and since then it has been prevalent in many countries and regions. Only one recombinant strain of ECoV was isolated from the small intestine of a donkey experiencing diarrhea in Shandong Province, China. [Objective] Understanding the genetic composition, genetic relationship, and biological characteristics of ECoV strains in China can lay a foundation for unveiling the epidemic status and genetic evolution trend of ECoV and provide materials for the research and development of products for the prevention and control of ECoV. [Methods] RT-PCR was employed to detect the stool samples from a horse experiencing diarrhea in Huangpi District, Wuhan City, Hubei Province. The virus was isolated from the positive samples and verified by indirect immunofluorescence assay (IFA) with monoclonal antibodies targeting the S1 protein of ECoV. Based on the whole genome sequencing results of the isolate, the phylogenetic analysis and sequence alignments of the whole genome, N gene, and NS2 gene were performed. [Results] An ECoV strain was successfully isolated and named ECoV-JL. Transmission electron microscopy (TEM) showed that the isolated virus particles were spheroidal and had a capsule membrane and a typical spiroid structure of coronaviruses. The tissue culture infectious dose 50% (TCID₅₀) of ECoV-JL reached a peak of 10^6.16 TCID₅₀/mL 72 h post infection in HRT-18 cells. ECoV-JL strains could infect three human cell lines: HRT-18 (human ileocecal cancer cells), Caco-2 (human colorectal adenocarcinoma cells), and Huh7 (human liver cancer cells). The genome sequence of ECoV-JL and the ECoV genome sequences in GenBank showed the similarity within the range of 97.9%–99.0%. ECoV-JL was in a separate branch of the phylogenetic tree and far related to other strains, which indicated that ECoV-JL might be derived from recombination mutations. The NS2 gene presented more mutations, and the difference in NS2 gene was the main reason for the poor homology between ECoV-JL and other strains. [Conclusion] We isolated and identified an ECoV strain from the stool samples of horses with diarrhea and named it ECOV-JL. The study about the biological characteristics and phylogenetic relationship of this strain reflected the characteristics of the epidemic strains in Hubei Province, providing a clue for the epidemic status and evolution trend of ECoV in China.

Atopic dermatitis (AD) is a highly prevalent allergic skin disease characterised by recurrent attacks and severe itching. The pathogenesis of AD involves a variety of factors including genetic susceptibility, epidermal barrier dysfunction, microbiome dysbiosis, immune imbalance, and the environment, while the available therapeutic drugs have severe side effects and limited efficacy. Studies have demonstrated that gut microbiota, particularly probiotics, play a role in AD. Probiotics can alleviate AD symptoms by inhibiting pathogens, enhancing barriers, improving the intestinal environment, and balancing the Th1/Th2 immune response, among other mechanisms. In this review, we summarized the skin and intestinal microecological characteristics of AD patients and systematically elucidated the mechanisms of probiotics in alleviating AD from the pathogenesis and influencing factors of AD, aiming to provide theoretical support for probiotics in the treatment of AD and related allergic skin diseases.

Hepatitis E virus (HEV) is a major zoonotic pathogen that causes acute viral hepatitis worldwide. HEV has high genetic diversity, and the incidence of various genotypes or subtypes is strongly correlated with host species, geographic location, and prevention and control methods. HEV strains HEV-3, comprising 3a–3i subtypes, were present in Europe and America, whereas HEV-3 and HEV-4 were prevalent in Asia. The epidemic strains in China have evolved from HEV-1 to HEV-4. Recent studies have shown that gene recombination, amino acid mutations, and synonymous codon usage patterns are part of the mechanisms underlying HEV evolution. In particular, amino acid mutations are the main driving force for the continued prevalence of the virus. This paper reviews the classification, global epidemic characteristics, and evolutionary mechanism of HEV, aiming to provide a reference for the prevention and control of hepatitis E and vaccine development.

The roles of gut microbiota and its metabolites in the pathogenesis and rehabilitation of neurodegenerative diseases, gastrointestinal diseases, and musculoskeletal systemic diseases in the elderly are receiving increasing attention. Gut microbiota and its metabolites can regulate the functions of the cranial nervous system and the musculoskeletal system through various pathways, involving the immune, endocrine, and nervous systems. Conversely, the gut, brain, and musculoskeletal system can act on the intestinal system via inflammatory, metabolic, and mitochondrial pathways to regulate the gut microbiota. Accordingly, bidirectional signaling mechanisms are formedvia the gut-brain, gut-muscle, and gut-brain-muscle axes, which affect the organism health. This review summarizes that gut microbiota establishes gut-brain-muscle interconnections mainly through metabolites, intestinal permeability, and immune-neural pathways, providing new ideas for improving the brain neuroplasticity and muscle health.

[Objective] To investigate the diversity and community structure of soil bacteria in the farmlands in Qinghai Province. [Methods] High-throughput sequencing was employed to analyze the bacterial community structure and diversity in the soil samples of farmlands growing wheat, oilseed rape, and highland barley in Dulan, Huzhu, Gonghe, and Datong counties. Furthermore, the relationship between bacterial community structure and soil physicochemical properties was analyzed. [Results] The pH, moisture, and organic matter of soil, as well as the Chao1 and Shannon indexes and linear discriminant analysis effect size (LEfSe) of soil bacteria, showed significant differences in some of these indexes (P＜0.01) but no significant differences among the three crops (P > 0.05). The results of principal component analysis (PCA) showed that the bacterial community structure was different among different regions but highly similar in the farmlands of the three crops. A total of 3 127 operational taxonomic units (OTUs) and 3 694 OTUs were common in the four regions and in the farmlands of the three crops, respectively. The OTUs of soil bacteria were identified as 423 species, 450 genera, 276 families, 192 orders, 93 classes of 36 phyla. The four regions or three crops had similar dominant phyla, genera, and species, while these taxa differed in relative abundance. Soil moisture, pH, and organic matter were significantly correlated with Chao1 and Shannon indexes. Soil pH and organic matter had significantly positive or negative correlations with unclassified species, unclassified RB41, and unclassifiedSphingomonas. Chao1 and Shannon indexes had significantly negative correlations with unclassifiedSphingomonas but positive correlations with unclassified RB41 and unclassifiedVicinamibacteraceae. [Conclusion] Regional differences had significant effects on soil physicochemical properties, bacterial community structure and diversity, which were more obvious than those of crop differences.

[Objective] To investigate the effects and mechanism ofLactobacillus plantarum postbiotics at different doses on amelioratingSalmonellaenterica Typhimurium (ST) infection in mice. [Methods] Sixty 5-week C57BL/6 mice were randomized into five groups: Control, ST, CFS-L+ST, CFS-M+ST, and CFS-H+ST.Lactobacillus plantarum postbiotics (cell-free supernatant, CFS) was administrated at low (L), medium (M), and high (H) doses (50, 100, and 200 μL, respectively) for 21 days. On day 22, mice were orally challenged with ST at 3×10⁸ CFU, and the samples were collected three days later. [Results] Compared with the control group, CFS-L+ST and CFS-M+ST groups showed no significant changes in body weight gain, while the CFS-H+ST group showed a significant decrease (P<0.05). The CFS-M+ST and CFS-H+ST groups alleviated ST-induced body weight loss (P<0.05). CFS pretreatment reduced ST-induced bacterial translocation in the colon, liver, spleen, and brain (P<0.05) and alleviated the pathological damages in the colon and spleen. ST reduced the levels of acetic acid and butyric acid in the cecum, which, however, increased in the CFS-M+ST group (P>0.05). Compared with the ST group, CFS-M+ST alleviated the inflammatory response by lowering the levels of pro-inflammatory cytokines including interleukin-1beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) (P<0.05) and elevating the levels of anti-inflammatory cytokines including interleukin-4 (IL-4) and interleukin-10 (IL-10) (P<0.05). Moreover, CFS-M+ST suppressed ST-induced inflammation by modulating the nucleotide-binding oligomerization domain-like receptor (NLR) family pyrin domain-containing protein 3 (NLRP3) inflammasome, as indicated by the down-regulated mRNA levels ofNLRP3, apoptosis-associated speck-like protein (ASC), cysteine-dependent aspartate-specific protease 1 (caspase-1), and gasdermin D (GSDMD) (P<0.05). Furthermore, CFS inhibited NLRP3 inflammasome by blocking the upstream key nuclear factor kappa beta (NF-κB) pathway, as indicated by the down-regulated expression levels of myeloid differentiation factor 88 (MyD88), tumor necrosis factor receptor-associated factor 6 (TRAF6), transforming growth factor beta-activated kinase 1 (TAK1), and NF-κB (P<0.05). [Conclusion] L.plantarum postbiotics CFS alleviated theS.enterica Typhimurium infection and inflammatory responses in mice by inhibiting the NF-κB-mediated NLRP3 inflammasome, and the pretreatment with medium-dose CFS showed the best effects.

[Objective] Microsporidia are obligate intracellular parasites capable of infecting a wide range of animal species, including both humans and animals of economic interests. We exploredNosemabombycis hexokinase (NbHK) in terms of the expression, subcellular localization, regulatory functions, and interacting proteins inBombyxmori embryo cells, aiming to provide insights into the function and mechanism of this protein during infection. [Methods] We prepared a polyclonal antibody against NbHK to analyze the expression and localization of NbHK inN.bombycis-infected BmE cells by using Western blotting and the indirect immunofluorescent assay. Overexpression and RNA interference experiments were performed to assess the impact of NbHK on pathogen proliferation. RNA-seq was employed to analyze the transcriptional responses of the NbHK-transgenic BmE cells. A biotin-streptavidin system and mass spectrometry were employed to identify the interacting proteins of NbHK from NbHK::APEX2-transgenic BmE cells. [Results] NbHK was predominantly localized in the nucleus of infected cells, with consistently upregulated expression during infection. The overexpression of NbHK significantly increased the pathogen load, while the knock-down of NbHK suppressed pathogen proliferation, which indicated the crucial roles of NbHK during infection. RNA-seq analysis identified 94 differentially expressed genes (DEGs) responsive to infection, comprising 58 up-regulated genes and 36 down-regulated genes. The enrichment analysis of DEGs revealed significant activation of pathways related to cell lifespan regulation and protein processing in the endoplasmic reticulum while significant inhibition of the mitophagy pathway. Additionally, we identified host proteins including nucleoprotein translocated promoter region (NTPR) in the nucleus that potentially interacted with NbHK. [Conclusion] NbHK is secreted into silkworm nucleus to modulate the expression of genes involved in multiple pathways for promoting pathogen proliferation. Our study offers novel insights into the roles of NbHK in the infection ofN.bombycis.

Pyrroloquinoline quinone (PQQ), the third oxidoreductase coenzyme discovered in the nature after nicotinamide and riboflavin, is ubiquitous in bacteria, fungi, plants, and animals. PQQ participates in a variety of life activities and has anti-inflammation, anti-oxidation, cell metabolism-enhancing, and cardioprotective activities, demonstrating broad application prospects in pharmaceuticals, agriculture, food and other fields. Therefore, the large-scale production of PQQ is the primary problem that needs to be solved at present. Microbial fermentation is a primary production method of PQQ. Deciphering the biosynthesis pathway and regulatory mechanism of PQQ is essential for the screening and breeding of strains with short production periods and high yields by metabolic engineering, which has been a hot topic in this field. This paper summarizes the synthesis pathways, strain screening and breeding, microbial production, and purification processes of PQQ, aiming to provide a reference for further research and application of PQQ.

[Objective] To explore the changes in the yield and composition of extracellular polymeric substances (EPS) ofAlternaria sp. CGMCC 17463, a strain of dark septate endophyte (DSE), cultured for different time periods. [Methods] We conducted the shake flask experiment to compare the yield, structure, composition, and activity of EPS synthesized by a DSE strain cultured for different time periods. [Results] From day 4 to 12, the growth of the DSE strain entered the logarithmic and stationary phases. During this period, the EPS synthesis rate was high, with the yield reaching 1.41 g/L on day 12. Afterwards, the EPS synthesis rate gradually decreased. The component analysis revealed that the extracellular polysaccharide content was the highest on day 12 in the EPS samples of equal mass. As the growth of DSE continued and entered the decline phase, mycelial lysis occurred, significantly increasing the protein content in the EPS. Functional group analysis showed that as the incubation time was extended, the functional groups in the EPS presented changes only in the content but not species. The results of scanning electron microscopy and particle size analysis showed that the EPS composition gradually changed with the increase in incubation time. Specifically, the EPS components with the particle size smaller than 5 μm presented increased volume percentage, while those with the particle size larger than 100 μm showed gradually decreased volume percentage. Furthermore, the EPS possessed the ability to scavenge oxygen free radicals and retain water, which were significantly influenced by the changes in EPS composition. [Conclusion] The day 12 marks the optimal time point for the production of EPS with high polysaccharide content, while the day 24 marks the optimal time point for the production of EPS with high protein content. This result establishes a foundation for the application of EPS in the complex eco-environment of mines.

[Objective] To analyze the influence of pH on sulfate-reducing properties of sulfate-reducing bacteria enriched from marine sediments, identify the bacterial community composition, predict the key genes of sulfate reduction, and explore the mechanism of sulfate reduction. [Methods] The sulfate reduction rates of sulfate-reducing bacteria at different pH conditions were determined. On this basis, high-throughput sequencing and PICRUSt were employed to analyze the dominant sulfate-reducing bacteria and the relative abundance of sulfate-reducing genes. [Results] The biomass (OD₆₀₀) and sulfate reduction rate of sulfate-reducing bacteria varied significantly under different pH conditions (P＜0.01) and reached their peak values (0.34±0.01 and 96.52%±0.44%, respectively) at pH 5.0. According to the high-throughput sequencing data, the abundance and diversity of bacteria were the highest at pH 5.0. The dominant bacteria werePseudomonas andBacillus, and the assimilatory sulfate reduction-related genes had higher abundance. [Conclusion] Sulfate-reducing bacteria are suitable to be enriched and cultured at pH 5.0. Under this condition, the high sulfate reduction rate is attributed to the assimilatory sulfate reduction pathway. The findings provide experimental support for revealing sulfate reduction mechanism and broaden the germplasm resources of sulfate-reducing bacteria for application.