Unveiling the pathogenic and multidrug-resistant profiles of Vibrio alfacsensis: A potential identified threat in turbot (Scophthalmus maximus) aquaculture.

Vibrio alfacsensis is traditionally seen as an environmental symbiont within its genus, with no detailedly documented pathogenicity in marine aquaculture to date. This study delves into the largely unexplored pathogenic potential and emerging antibiotic resistance of V. alfacsensis. The VA-1 strain, isolated from recirculating aquaculture system (RAS) effluent of cultured turbot (Scophthalmus maximus), underwent comprehensive analysis including biochemical identification, antibiotic susceptibility testing and reinfection trials. The results confirmed VA-1's pathogenicity and significant multiple antibiotic resistance. VA-1 could induce systemic infection in turbot, with symptoms like kidney enlargement, exhibiting virulence comparable to known Vibrio pathogens, with an LD50 around 2.36 × 106 CFU/fish. VA-1's remarkable resistance phenotype (14/22) suggested potential for genetic exchange and resistance factor acquisition in aquaculture environments. Phylogenetic analysis based on 16S rDNA sequences and whole-genome sequencing has firmly placed VA-1 within the V. alfacsensis clade, while genome-wide analysis highlights its similarity and diversity in relation to strains from across the globe. VA-1 contained numerous replicons, indicating the possibility for the spread of resistance and virulence genes. This study suggests V. alfacsensis may acquire and transfer pathogenic and resistant traits through horizontal gene transfer, a likelihood intensified by changing environmental and aquaculture conditions, highlighting the need for vigilant pathogen monitoring and new non-antibiotic treatments.

Gut Microbiota and Metabolites May Play a Crucial Role in Sea Cucumber Apostichopus japonicus Aestivation.

The constant increase in temperatures under global warming has led to a prolonged aestivation period for Apostichopus japonicus, resulting in considerable losses in production and economic benefits. However, the specific mechanism of aestivation has not been fully elucidated. In this study, we first tried to illustrate the biological mechanisms of aestivation from the perspective of the gut microbiota and metabolites. Significant differences were found in the gut microbiota of aestivating adult A. japonicus (AAJSD group) compared with nonaestivating adult A. japonicus (AAJRT group) and young A. japonicus (YAJRT and YAJSD groups) based on 16S rRNA gene high-throughput sequencing analysis. The abundances of Desulfobacterota, Myxococcota, Bdellovibrionota, and Firmicutes (4 phyla) in the AAJSD group significantly increased. Moreover, the levels of Pseudoalteromonas, Fusibacter, Labilibacter, Litorilituus, Flammeovirga, Polaribacter, Ferrimonas, PB19, and Blfdi19 genera were significantly higher in the AAJSD group than in the other three groups. Further analysis of the LDA effect size showed that species with significant variation in abundance in the AAJSD group, including the phylum Firmicutes and the genera Litorilituus, Fusibacter, and Abilibacter, might be important biomarkers for aestivating adult A. japonicus. In addition, the results of metabolomics analysis showed that there were three distinct metabolic pathways, namely biosynthesis of secondary metabolites, tryptophan metabolism, and sesquiterpenoid and triterpenoid biosynthesis in the AAJSD group compared with the other three groups. Notably, 5-hydroxytryptophan was significantly upregulated in the AAJSD group in the tryptophan metabolism pathway. Moreover, the genera Labilibacter, Litorilituus, Ferrimonas, Flammeovirga, Blfdi19, Fusibacter, Pseudoalteromonas, and PB19 with high abundance in the gut of aestivating adult A. japonicus were positively correlated with the metabolite 5-HTP. These findings suggest that there may be potential biological associations among the gut microbiota, metabolites, and aestivation in A. japonicus. This work may provide a new perspective for further understanding the aestivation mechanism of A. japonicus.

A systematic review, meta-analysis and meta-regression of the global prevalence of foodborne Vibrio spp. infection in fishes: A persistent public health concern.

Human vibriosis, caused by pathogenic Vibrio spp., such as Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus, has been increasing worldwide, mediated by increasing consumption of seafood. The present study was conducted to examine the global prevalence of V. vulnificus, V. parahaemolyticus and V. cholerae in fishes. We searched PubMed, Web of Science, Scopus, and CNKI for peer-reviewed articles and dissertations prior to December 31, 2021. A total of 24,831 articles were retrieved, and 82 articles contained 61 fish families were included. The global pooled prevalence of V. cholerae, V. parahaemolyticus and V. vulnificus in fishes was 9.56 % (95 % CI: 2.12-20.92), 24.77 % (95 % CI: 17.40-32.93) and 5.29 % (95 % CI: 0.38-13.61), respectively. Subgroup and meta-regression analyses showed that study-level covariates, including temperature, country, continent, origin and detection methods partly explained the between-study heterogeneity. These heterogeneities were underpinned by differences of the three Vibrio spp. in fishes at geographical and climatic scales. These results reveal a high global prevalence of pathogenic Vibrio spp. in fishes and highlight the need for implementation of more effective prevention and control measures to reduce food-borne infection in humans.

Characterization of bacterial community changes and antibiotic resistance genes in lamb manure of different incidence.

Bacterial enteritis is the most important disease in lamb for breeding greatly affects the growth of animals. Changes in the community of intestinal flora can cause the disorder of the colonic environment induced diarrhea. This study aimed to investigate the relationship between the incidence of bacterial enteritis and the number of intestinal microbiome, then the prevalence of drug-resistant genes was detected. Fecal samples were collected at five fattening sheep farms with different incidence of bacterial enteritis, pathogenic bacteria were isolated and identified, drug sensitivity tests were performed. Then, changes in number and structure of intestinal flora were compared by 16S rDNA V3-V4 region high-throughput sequencing, and the ARGs were detected using high-throughput real-time PCR. Our results revealed that the microbial communities were positively correlated with the incidence of bacterial enteritis in different farms. Bacterial communities were higher in YJ (with highest incidence of diarrhea) than any other farms. However, the ARGs seemed not to be more affected by the incidence of bacterial enteritis, but one of the significant findings to emerge from this study is that MCR-1 and NDM are detected in manure. This study has provided an insight of the changes occurring in intestinal flora and AGRs in fattening sheep farms with diverse incidence of bacterial enteritis.

[Cloning and expression analysis of tocopherol cyclase gene in Carthamus tinctorius].

The tocopherol cyclase was one of the key enzymes in plant vitamin E biosynthesis pathway. According to the study of Carthamus tinctorius transcriptome data,the Tocopherol cyclase gene was obtained using RT-PCR techniques and named CtTC . Bioinformatics analysis showed theopen reading frame （ORF）of CtTC was 1 524 bp. The putative protein contained 507 amino acids with a predicted molecular mass of 62.9 kDa and theoretically isoelectric point was 5.01.Signal peptide analysis showed that it was a non secretory protein, and there was no signal peptide. The subcellular localization showed that the CtTC protein was located in the chloroplast. The expression of CtTC gene in safflower seeds at different development stages was determined by quantitative real-time PCR, it was found that the highest expression level of CtTC gene was detected in 50 DAF.Quantitative RT-PCR analysis suggested that expression of CtTC is induced and strengthened by drought stresses. This research provided a candidate gene for metabolic engineering of vitamin E and resisting stress.