Deletion of speA and aroC genes impacts the pathogenicity of Vibrio anguillarum in spotted sea bass.

Vibrio anguillarum is one of the major pathogens responsible for bacterial infections in marine environments, causing significant impacts on the aquaculture industry. The misuse of antibiotics leads to bacteria developing multiple drug resistances, which is detrimental to the development of the fisheries industry. In contrast, live attenuated vaccines are gradually gaining acceptance and widespread recognition. In this study, we constructed a double-knockout attenuated strain, V. anguillarum ΔspeA-aroC, to assess its potential for preparing a live attenuated vaccine. The research results indicate a significant downregulation of virulence-related genes, including Type VI secretion system, Type II secretion system, biofilm synthesis, iron uptake system, and other related genes, in the mutant strain. Furthermore, the strain lacking the genes exhibited a 67.47% reduction in biofilm formation ability and increased sensitivity to antibiotics. The mutant strain exhibited significantly reduced capability in evading host immune system defenses and causing in vivo infections in spotted sea bass (Lateolabrax maculatus), with an LD50 that was 13.93 times higher than that of the wild-type V. anguillarum. Additionally, RT-qPCR analysis of immune-related gene expression in spotted sea bass head kidney and spleen showed a weakened immune response triggered by the knockout strain. Compared to the wild-type V. anguillarum, the mutant strain caused reduced levels of tissue damage. The results demonstrate that the deletion of speA and aroC significantly reduces the biosynthesis of biofilms in V. anguillarum, leading to a decrease in its pathogenicity. This suggests a crucial role of biofilms in the survival and invasive capabilities of V. anguillarum.

Effects of Inducible Nitric Oxide Synthase (iNOS) Gene Knockout on the Diversity, Composition, and Function of Gut Microbiota in Adult Zebrafish.

The gut microbiota constitutes a complex ecosystem that has an important impact on host health. In this study, genetically engineered zebrafish with inducible nitric oxide synthase (iNOS or NOS2) knockout were used as a model to investigate the effects of nos2a/nos2b gene single knockout and nos2 gene double knockout on intestinal microbiome composition and function. Extensive 16S rRNA sequencing revealed substantial changes in microbial diversity and specific taxonomic abundances, yet it did not affect the functional structure of the intestinal tissues. Notably, iNOS-deficient zebrafish demonstrated a decrease in Vibrio species and an increase in Aeromonas species, with more pronounced effects observed in double knockouts. Further transcriptomic analysis of the gut in double iNOS knockout zebrafish indicated significant alterations in immune-related and metabolic pathways, including the complement and PPAR signaling pathways. These findings underscore the crucial interplay between host genetics and gut microbiota, indicating that iNOS plays a key role in modulating the gut microbial ecology, host immune system, and metabolic responses.

Identification of pyroptosis subtypes and prognosis model of hepatocellular carcinoma based on pyroptosis-related genes.

BACKGROUND: Hepatocellular carcinoma (HCC) is a common malignant tumor with poor prognosis. Pyroptosis, a type of programmed cell death, regulates tumor cell development. However, the role of pyroptosis-related genes (PRGs) in HCC and their association with prognosis are unclear. METHODS: We conducted bioinformatics analysis to identify PRGs in The Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC) patients. Consensus clustering classified patients into different subtypes. We used LASSO regression to established a pyroptosis subtype-related score (PSRS) related to prognosis. OncoPredict identified potential pharmaceuticals based on PSRS. RESULTS: We found 20 HCC-related PRGs in 335 TCGA-LIHC patients. Consensus clustering classified patients into two subtypes. Subtype I had better overall survival and higher response to anti-PD1 treatment. The prognostic model involving 20 genes predicted poorer prognosis for high-PSRS group. The model was validated in two external cohorts. OncoPredict identified 65 potential pharmaceuticals based on PSRS. CONCLUSION: Our investigation revealed a correlation between pyroptosis and HCC. We established PSRS as independent risk factors for predicting prognosis. The study paves the way for using PRGs as prognostic biomarkers and exploring personalized therapy for HCC.