Objective To develop a fluorescence method for Vibrio parahaemolyticus detection by the combination of CRISPR system and the hybridization chain reaction (HCR), thus achieving rapid, sensitive, and accurate detection of the pathogen. Methods Cascade probe (RP/I) and HCR hairpin structures were first designed according to a specific conserved sequences screened from V. parahaemolyticus. Subsequently, the feasibility, specificity, and sensitivity of the method were evaluated after the optimization of reaction conditions. Furthermore, V. parahaemolyticus-contaminated aquatic products were used to validate the interference resistance of the method. Results The cleavage of CRISPR/Cas13a was activated upon binding to the target RNA (T-RNA), leading to the trans-cleavage of the RP/I cascade probe and the release of I strand. Then, the released I strand subsequently triggered HCR, generating a significant fluorescence signal for target detection. The established method successfully distinguished target sequences with single-base, double-base, and triple-base mismatches and enabled the specific identification of V. parahaemolyticus against other non-target bacteria, including V. alginolyticus, V. vulnificus, V. harveyi, V. cholerae, and Escherichia coli, demonstrating excellent specificity. The assay showed a good linear correlation over a T-RNA concentration range of 25 pmol/L to 10 nmol/L. The corresponding linear regression equation was y=7 236.75×lg C_T-RNA-8 590.11 (R²=0.99, C represents the T-RNA concentration and y represents the fluorescence intensity), with the LOD of 1.01 pmol/L. The proposed method enabled rapid detection of RNA extracted from V. parahaemolyticus in various aquatic products, yielding results consistent with those obtained by RT-qPCR. Conclusion The fluorescence method based on CRISPR/Cas13a-HCR established in this study realizes rapid detection of V. parahaemolyticus, demonstrating good sensitivity, specificity, and accuracy.

Staphylococcus aureus, a common foodborne pathogen causing hospital-acquired infection, poses a grave threat to public health and safety, resulting in a substantial economic burden on the society. As a conditionally essential amino acid, arginine exhibits a dual role in the infection of S. aureus and the immune response of the host. On the one hand, arginine synthesis and catabolism are involved in pathogenic processes such as the biofilm formation and antibiotic resistance of S. aureus. On the other hand, arginine metabolites play an important role in anti-infective immunity, tissue repair, and wound healing through the modulation of macrophage polarization, immune modulation, metabolic reprogramming, and signaling. Recent studies suggest that arginine metabolism constitutes a regulatory hub for S. aureus-macrophage interactions, and its metabolic balance affects the progression and regression of infection and anti-infection. Consequently, targeting the arginine metabolic pathway to impede S. aureus infection by regulating host-pathogen metabolic interactions has emerged as a novel anti-S. aureus therapeutic strategy with significant translational medical relevance. In this review, we focus on the metabolic utilization of arginine to describe how S. aureus and macrophages exert their respective biological functions by competing for the utilization of arginine. In addition, we summarize the changes of arginine levels in macrophages during S. aureus infection to explore the feasible research directions and challenges of regulating arginine metabolism as a potential antimicrobial strategy in the future.

As a globally prevalent malignancy with poor prognosis, liver cancer exhibits a well-established pathological association with the gut microbiota (GM). In recent years, increasing attention has been paid to the role of the GM in the initiation and pathological progression of liver cancer, which often evolves through stages of hepatitis, liver fibrosis, cirrhosis, and ultimately liver cancer. The GM influences the development of liver cancer through multiple mechanisms, including the regulation of the hepatic immune microenvironment by the GM and its metabolites, the mediation of epigenetic modifications and exosomal signaling pathways, and the synergy with other risk factors. Notably, patients with liver cancer commonly demonstrate reduced GM diversity and enriched pathogenic bacteria. These findings offer a new theoretical foundation and suggest potential therapeutic strategies such as probiotic supplementation, rational antibiotic use, fecal microbiota transplantation, combination therapies integrating GM modulation with conventional treatments, and integrated treatment regimens based on the above methods. This article reviews the pathogenesis of liver cancer mediated by GM dysbiosis and the research advances in GM-targeted interventions in recent years, providing reference for future studies on the pathogenesis and treatment of liver cancer.

Heat shock protein family A member 8 (HSPA8) is a widely distributed molecular chaperone in cells. HSPA8 is involved in multiple cellular physiological processes, mainly including the correct folding and transport of proteins, stress responses, presentation of antigenic proteins, mediation of autophagy, and immune regulation. It is also crucial for maintaining the homeostasis of the intracellular environment. In addition, HSPA8 plays a key role in multiple processes of virus infections. This paper reviewed the important roles and molecular mechanisms of HSPA8 in processes such as virus adhesion, formation of virus glycoprotein-receptor complexes, internalization, uncoating, genome replication, assembly, and regulation of host metabolism and immune responses, with the hope of laying a foundation for the subsequent development of drugs targeting HSPA8 for the treatment of virus infections.

Coronaviruses pose a serious threat to human and animal health. Their main protease (Mpro) plays a critical role in both the viral life cycle and host immune regulation, serving as a key target for the development of broad-spectrum anti-coronavirus drugs. The core function of Mpro lies in its specific cleavage of viral polyproteins pp1a and pp1ab to release functional non-structural proteins (NSPs), thereby driving the assembly of the viral replication/transcription complex. Additionally, Mpro can target and cleave key molecules in host immune signaling pathways, facilitating viral immune evasion. Given its dual roles and highly conserved catalytic center, the research on Mpro has become a major focus in the field. This review systematically outlines the structural features and functional diversity of Mpro, with an emphasis on its catalytic mechanism in the viral replication cycle and its role in mediating immune suppression. Furthermore, this article details the screening methods and design strategies for Mpro inhibitors, aiming to offer theoretical foundations and novel insights for the development of anti-coronavirus drugs targeting this critical protein.

Understanding the source, colonization rules, and dynamic evolution process of the gut microbiota is of significant importance for regulating host health, given its crucial role in nutrient metabolism, immune regulation, and intestinal barrier function. This article comprehensively reviews the composition and functions of the gut microbiota and explores the origins and transmission pathways, with a particular focus on the effects of maternal-infant transmission and paternal inheritance on the structure and functions of the gut microbiota. We chart microbial assembly across pivotal life stages, distill the driving factors involved in the community assembly process, and critically appraise the advances in metagenomic and source-tracking toolkits. The review provides an integrated framework for microbiome-targeted strategies aimed at reconstructing a health-oriented gut ecosystem.

Actinobacteria are Gram-positive bacteria of major ecological and biotechnological importance, responsible for organic matter turnover in nature and serving as a primary source of antibiotics and other bioactive natural products. Their complex physiological adaptation and life cycles are regulated by sophisticated signal transduction networks. This review examines the metabolism, signaling, and regulatory networks of nucleotide second messengers including cyclic diadenosine monophosphate (c-di-AMP), cyclic di-guanosine monophosphate (c-di-GMP), adenosine monophosphate (cAMP), and (p)ppGpp in the morphologically complex Streptomyces with rich secondary metabolites and pathogenic Mycobacterium with host adaptation. We discuss how these second messengers interact with other signaling systems, such as two-component systems, quorum sensing, and protein acylation, to integrate environmental and developmental cues. This coordination regulates the growth, development, secondary metabolite biosynthesis, and environmental adaptation of actinobacteria. By synthesizing current knowledge, this review provides reference for understanding the integrity and dynamics of the signal transduction system of actinobacteria, as well as their potential applications in the basic research of life sciences and in the fields of biotechnology and medicine.

The enzootic nasal tumor of sheep and goats is a progressive and contagious disease caused by enzootic nasal tumor virus. It is mainly characterized by tumor growth in the mucosal epithelial tissue of the ethmoid bone and nasal turbinates within the nasal cavity of sheep and goats. In the later stage of the disease, the significant enlargement of tumor volume can lead to upper respiratory tract obstruction, which subsequently causes the affected animals to die of asphyxiation. This disease markedly reduces the production performance of infected animals, causing economic losses to the livestock industry. Moreover, it poses a threat to precious local breeds and core breeding flocks, resulting in the loss of high-quality breeding sheep. Consequently, it has become one of the major diseases threatening the sheep and goat industry. Currently, there are no vaccines or specific treatments for this disease. This article reviews enzootic nasal tumor virus in terms of the etiology, epidemiology, clinical symptoms, main pathological changes, diagnosis, and prevention and control, providing references and ideas for the prevention and control of this disease.

Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs). It can adhere to and colonize uroepithelial cells, disseminate systemically, and induce severe sepsis and subsequent renal failure, posing a substantial threat to global public health. Emerging evidence indicates that lactylation, a key post-translational modification (PTM) in macrophages, plays a crucial role in the host defense against UPEC infection. Notably, the UPEC CFT073 strain harbors ldhA, which encodes lactate dehydrogenase (LDH), an enzyme critical for lactate biosynthesis. However, the mechanism by which LdhA (the ldhA-encoded LDH) regulates macrophage lactylation during UPEC infection remains elusive. Objective To elucidate how LdhA modulates macrophage lactylation and thereby impacts UPEC pathogenicity. Methods Online bioinformatics tools were used to predict the functional domains and transmembrane regions of LdhA. The recombinant protein rLdhA was generated via molecular cloning, and its LDH activity was measured by a commercial LDH activity assay kit. Western blotting was performed to assess the cellular entry of rLdhA into macrophages and its regulatory effect on macrophage lactylation. Enzyme-linked immunosorbent assay (ELISA) was employed to measure the secretion of inflammatory cytokines in macrophages treated with rLdhA. The drug resistance profile of UPEC CFT073 (wild-type and ldhA-knockout strains) was analyzed via an automated microbial identification system. To evaluate the role of LdhA in UPEC pathogenicity, we treated mice with the wild-type UPEC CFT073 (CFT073^wt), ldhA-deficient mutant (CFT073^ΔldhA ), or rLdhA (with or without pretreatment with an LDH inhibitor) through intraperitoneal injection or tail vein injection, and then observed and quantified pathogenic phenotypes. Results LdhA harbored a LDH domain and was secreted extracellularly. We successfully established an expression system for ldhA and achieved efficient expression and purification of rLdhA. Functional assays confirmed that rLdhA exhibited LDH activity and can enter macrophages via clathrin-mediated endocytosis, subsequently enhancing macrophage lactylation in a dose-dependent manner. Additionally, rLdhA significantly inhibited lipopolysaccharide (LPS)-induced inflammatory cytokine production in macrophages. Furthermore, LdhA was found to substantially modulate the drug resistance profile of UPEC CFT073. In vivo studies demonstrated that LdhA promoted the pathogenicity of UPEC in a mouse infection model. Conclusion Collectively, our findings demonstrate that LdhA enhances UPEC pathogenicity by upregulating macrophage lactylation and suppressing the production of proinflammatory cytokines. However, the underlying molecular mechanisms mediating this regulatory cascade remain to be fully elucidated and warrant further exploration. This study offers a new theoretical basis for deciphering the pathogenic mechanisms of UPEC infections.

Objective To screen potential probiotics with antagonistic effects against Nocardia seriolae from the intestine of healthy largemouth bass (Micropterus salmoides). Methods Intestinal samples were collected from healthy largemouth bass, and strains were isolated and purified via serial dilution and spreading on TSA plates. The hole-punch method was adopted to select strains with antagonistic effects against N. seriolae as test strains for subsequent experiments. The species of the test strains were identified through morphological characterization, physiological and biochemical tests, 16S rRNA gene sequence alignment, and phylogenetic analysis. Additionally, the growth characteristics, adhesion ability, antibacterial activity of cell-free fermentation supernatants, and biosafety of the test strains were determined and analyzed. Results Among the 40 bacterial strains isolated from the intestinal samples of healthy largemouth bass, two strains (XXLC06 and XXLC08) with stable and significant antagonistic effects against N. seriolae were selected. XXLC06 was identified as Lysinibacillus macroides and XXLC08 as Lysinibacillus fusiformis. Both strains grew well at 25-37 ℃, salinities of 5‰-30‰, and pH 5.5-9.0, with survival rates higher than 53% at 0.3% and 0.5% bile salt concentrations. Auto-aggregation assays showed that the auto-aggregation rates of XXLC06 and XXLC08 after 8 h were 68.09% and 63.16%, respectively. In the three organic solvents, both XXLC06 and XXLC08 exhibited hydrophobicity rates exceeding 50%. After co-incubation with N. seriolae for 8 h, the co-aggregation rates of the two strains reached 54.62% and 52.44%, respectively. The diameters of the inhibition zones of cell-free fermentation supernatants of XXLC06 and XXLC08 against N. seriolae were (28.15±0.44) mm and (22.63±0.52) mm, respectively. Neither strain showed hemolytic activity, and both were sensitive to 23 tested antibacterial agents. Acute toxicity tests confirmed that they were non-pathogenic to largemouth bass. Conclusion Strains XXLC06 and XXLC08 exhibited favorable growth adaptability, adhesion capability, biosafety, and stable antagonistic activity in vitro . This study provides potential probiotic resources and experimental evidence for the control of N. seriolae.