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Fish & Shellfish Immunology Jun 2024Akirin2 is pivotal for regulating host immunological responses in vertebrates, including antibacterial immunity and inflammation. However, the functional significance of...
Akirin2 is pivotal for regulating host immunological responses in vertebrates, including antibacterial immunity and inflammation. However, the functional significance of Akirin2 in invertebrates remains largely unexplored. In this study, we cloned the complete cDNA sequence of Akirin2 from A. japonicus (AjAkirin2) and elucidated its immunological mechanism upon pathogen infection. The whole AjAkirin2 cDNA sequence spanned 1014 bp, which comprised a 630 bp open reading frame encoding 209 amino acids, a 230 bp 5'-untranslated region (UTR), and a 154 bp 3'-UTR. Spatial expression analysis displayed constitutive expression of AjAkirin2 in all examined tissues. Both mRNA and protein expression abundance of the AjAkirin2 showed considerably high in coelomocytes of sea cucumbers challenged with Vibrio splendidus or stimulated with lipopolysaccharide. In addition, we found that sea cucumbers with 10 CFU/mL V. splendidus infection had a lower survival rate upon AjAkirin2 knockdown. Mechanistically, the result of GST-pull down and co-IP assays indicated that AjAkirin2 directly interacted with Aj14-3-3ζ. Moreover, we also detected that AjAkirin2 positively regulated Aj14-3-3ζ expression in sea cucumber coelomocytes. Furthermore, the knockdown of AjAkirin2 or Aj14-3-3ζ resulted in increasing intracellular bacteria load and suppressed the expression of key genes of the NF-κB signaling pathway (p65 and p105) and inflammatory cytokines including IL-17, VEGF, and MMP-1. In summary, these results confirmed the critical role of AjAkirin2 in mediating innate immune responses against V. splendidus infection via interaction with Aj14-3-3ζ and thereby exerting antibacterial function.
Topics: Animals; Vibrio; Stichopus; Immunity, Innate; Phylogeny; Amino Acid Sequence; 14-3-3 Proteins; Gene Expression Regulation; Sequence Alignment; Gene Expression Profiling; Base Sequence
PubMed: 38685443
DOI: 10.1016/j.fsi.2024.109592 -
Proceedings of the National Academy of... May 2024Several microbial genomes lack textbook-defined essential genes. If an essential gene is absent from a genome, then an evolutionarily independent gene of unknown...
Several microbial genomes lack textbook-defined essential genes. If an essential gene is absent from a genome, then an evolutionarily independent gene of unknown function complements its function. Here, we identified frequent nonhomologous replacement of an essential component of DNA replication initiation, a replicative helicase loader gene, in . Our analysis of genomes revealed two genes with unknown function, named and , that were substantially enriched in genomes without the known helicase-loader genes. These genes showed no sequence similarities to genes with known function but encoded proteins structurally similar with a viral helicase loader. Analyses of genomic syntenies and coevolution with helicase genes suggested that encodes a helicase loader. The in vitro assay showed that VdhL1 and VdhL2 promote the helicase activity of DnaB. Furthermore, molecular phylogenetics suggested that / were derived from phages and replaced an intrinsic helicase loader gene of over 20 times. This high replacement frequency implies the host's advantage in acquiring a viral helicase loader gene.
Topics: Vibrionaceae; DNA Helicases; DNA Replication; Phylogeny; Bacterial Proteins; Viral Proteins; Bacteriophages; Evolution, Molecular; Genome, Bacterial; DnaB Helicases; Vibrio
PubMed: 38683976
DOI: 10.1073/pnas.2317954121 -
Fish & Shellfish Immunology Jun 2024Toll-like receptors (TLRs) are one of the extensively studied pattern recognition receptors (PRRs) and play crucial roles in the immune responses of vertebrates and...
Toll-like receptors (TLRs) are one of the extensively studied pattern recognition receptors (PRRs) and play crucial roles in the immune responses of vertebrates and invertebrates. In this study, 14 TLR genes were identified from the genome-wide data of Octopus sinensis. Protein structural domain analysis showed that most TLR proteins had three main structural domains: extracellular leucine-rich repeats (LRR), transmembrane structural domains, and intracellular Toll/IL-1 receptor domain (TIR). The results of subcellular localization prediction showed that the TLRs of O. sinensis were mainly located on the plasma membrane. The results of quantitative real-time PCR (qPCR) showed that the detected TLR genes were differentially expressed in the hemolymph, white bodies, hepatopancreas, gills, gill heart, intestine, kidney, and salivary gland of O. sinensis. Furthermore, the present study investigated the expression changes of O. sinensis TLR genes in hemolymph, white bodies, gills, and hepatopancreas in different phases (6 h, 12 h, 24 h, 48 h) after stimulation with PGN, poly(I: C) and Vibrio parahaemolyticus. The expression of most of the TLR genes was upregulated at different time points after infection with pathogens or stimulation with PAMPs, a few genes were unchanged or even down-regulated, and many of the TLR genes were much higher after V. parahaemolyticus infection than after PGN and poly(I:C) stimulation. The results of this study contribute to a better understanding of the molecular immune mechanisms of O. sinensis TLRs genes in resistance to pathogen stimulation.
Topics: Animals; Toll-Like Receptors; Vibrio parahaemolyticus; Octopodiformes; Immunity, Innate; Gene Expression Regulation; Phylogeny; Gene Expression Profiling; Poly I-C; Peptidoglycan; Arthropod Proteins; Pathogen-Associated Molecular Pattern Molecules
PubMed: 38679344
DOI: 10.1016/j.fsi.2024.109591 -
Journal of Water and Health Apr 2024Degradation of water quality is an emerging issue in many developing countries. In this context, industrial and domestic effluents heavily contaminate the coast of...
Degradation of water quality is an emerging issue in many developing countries. In this context, industrial and domestic effluents heavily contaminate the coast of Moknine Continental Sebkha in Tunisia. The present study aimed to biomonitor the seawater quality of the Moknine Continental Sebkha coast using physicochemical and ecotoxicological approaches. The ecotoxicological assessment was performed using three species representing different trophic levels, namely , , and . In the physicochemical analysis such as BOD (biochemical oxygen demand), COD (chemical oxygen demand), TSS (total suspended solids), TOC (total organic carbon), NO (nitrate), AOX (adsorbable organic halogen), the recorded levels of pH and total suspended solids did not comply with the Tunisian standard (NT.09.11/1983). The ecotoxicological data confirmed that the tested water samples displayed toxicity to two test indicators and . A targeted chemical screening of the Moknine Continental Sebkha coast previously performed revealed the presence of total mercury, four phthalate acid esters, and one non-phthalate plasticizer, a fact that could explain the observed ecotoxicological effects and therefore might harm the biotic area and the health of the surrounding population.
Topics: Tunisia; Aliivibrio fischeri; Water Pollutants, Chemical; Environmental Monitoring; Seawater; Ecotoxicology; Lepidium sativum; Chlorophyta
PubMed: 38678430
DOI: 10.2166/wh.2024.035 -
Zhonghua Liu Xing Bing Xue Za Zhi =... Apr 2024To explore the regulation mechanism of the quorum sensing regulator AphA on the functional activity of type Ⅵ secretion system VflT6SS2 in . Western Blot analysis...
To explore the regulation mechanism of the quorum sensing regulator AphA on the functional activity of type Ⅵ secretion system VflT6SS2 in . Western Blot analysis was used to detect the relative expression and secretion of VflT6SS2 signature component hemolysin-coregulated protein (Hcp) in wild type (WT), Δ and corresponding complementary strains. Quantitative reverse transcription PCR and luminescence activity assay of the promoter- fusion system was used to measure the mRNA expression levels and promoter activity of the VflT6SS2 core and accessory gene-cluster representative genes 2, (2) and (2), and the quorum sensing regulator HapR in WT and Δ strains. A point mutation experiment combined with a luminescence activity assay was used to verify the regulatory binding site of AphA in the 2b promoter region. Electrophoretic mobility shift assay (EMSA) was used to determine AphA binding to the promoter. The mRNA expression levels of 2, (2), (2), and as well as the protein expression and secretion levels of Hcp in Δ strain, were significantly higher than those in the WT strain. The promoter activities of the VflT6SS2 core cluster, 2a, 2a, and were higher in Δ strain than in the WT strain, while the promoter activity of 2b showed the opposite trend. The promoter sequence analysis of 2a and 2b found significant differences in the region from -335 bp to -229 bp, and two potential AphA binding sites on 2b. The promoter activity of 2b decreased significantly after the point mutation of the two potential AphA binding sites. EMSA results showed that AphA binds directly to the promoter region of . AphA indirectly inhibits the regulation of the VflT6SS2 core and accessory gene clusters at the promoter level by directly repressing the expression of . AphA showed opposite regulation patterns for 2a and 2b, and AphA could positively regulate the expression of 2b by directly binding to the 2b promoter region (-335 bp to -229 bp).
Topics: Quorum Sensing; Vibrio; Bacterial Proteins; Promoter Regions, Genetic; Gene Expression Regulation, Bacterial; Type VI Secretion Systems; Multigene Family
PubMed: 38678354
DOI: 10.3760/cma.j.cn112338-20231215-00354 -
Fish & Shellfish Immunology Jun 2024Vibrio harveyi causes high mortality and severely limits grouper culture. The gut microbiota is an important biological barrier against pathogen invasion. In this study,...
Vibrio harveyi causes high mortality and severely limits grouper culture. The gut microbiota is an important biological barrier against pathogen invasion. In this study, we investigated dynamic changes in the intestinal microbial community, gene transcription and immune responses signatures of pearl gentian grouper (Epinephelus fuscoguttatus♂ × Epinephelus lanceolatus♀) at 0, 3 and 7 days (referred to as d0, d3 and d7 groups, respectively) after infection with V. harveyi. The results demonstrated that the d7 treatment reduced the gut microbial diversity and increased the proportion of Proteobacteria and Cyanobacteria. Notably, several putative pathogenic genera (Sphingomonas and Bacteroides) proliferated, while putative probiotic genera (Rhodococcus and Lactobacillus) reduced, and these changes in intestinal bacteria might be correlated to the alterations of host immune-related molecules. The d3 and d7 treatments also altered the histomorphology and gene transcription profiles mainly associated with immune function in intestine, such as 'MAPK signaling pathway', 'Apoptosis' and 'Toll-like receptor (TLR) signaling pathway'. Furthermore, d3 group induced a homeostatic dysregulation of the antioxidant system, cytokines and TLR signaling, with a tendency to gradually return to a normal state in d7 group, along with the apoptosis process. The pathogenic infection suppressed the expression of JNK pathway and enhanced the ERK pathway. In conclusion, the dysbiosis of the intestinal bacterial communities caused by the immune changes that occurred during V. harveyi infection disrupted the intestine health in the pearl gentian grouper. These results provided a comprehensive understandings of the immune defense mechanisms in fish and valuable references to develop disease control strategies in grouper aquaculture.
Topics: Animals; Vibrio; Gastrointestinal Microbiome; Fish Diseases; Bass; Vibrio Infections; Immunity, Innate; Transcription, Genetic
PubMed: 38677631
DOI: 10.1016/j.fsi.2024.109590 -
International Journal of Food... Jun 2024Vibrio parahaemolyticus (V. parahaemolyticus) is a common seafood-borne pathogen that can colonize the intestine of host and cause gastroenteritis. Biofilm formation by...
Vibrio parahaemolyticus (V. parahaemolyticus) is a common seafood-borne pathogen that can colonize the intestine of host and cause gastroenteritis. Biofilm formation by V. parahaemolyticus enhances its persistence in various environments, which poses a series of threats to food safety. This work aims to investigate the function of rcpA gene in biofilm formation and virulence of V. parahaemolyticus. Deletion of rcpA significantly reduced motility, biofilm biomass, and extracellular polymeric substances, and inhibited biofilm formation on a variety of food and food contact surfaces. In mice infection model, mice infected with ∆rcpA strain exhibited a decreased rate of pathogen colonization, a lower level of inflammatory cytokines, and less tissue damage when compared to mice infected with wild type strain. RNA-seq analysis revealed that 374 genes were differentially expressed in the rcpA deletion mutant, which include genes related to quorum sensing, flagellar system, ribosome, type VI secretion system, biotin metabolism and transcriptional regulation. In conclusion, rcpA plays a role in determining biofilm formation and virulence of V. parahaemolyticus and further research is necessitated to fully understand its function in V. parahaemolyticus.
Topics: Vibrio parahaemolyticus; Biofilms; Animals; Virulence; Mice; Bacterial Proteins; Vibrio Infections; Gene Expression Regulation, Bacterial; Female
PubMed: 38677238
DOI: 10.1016/j.ijfoodmicro.2024.110714 -
Foods (Basel, Switzerland) Apr 2024A novel storage technique that combines the low-frequency electric field (LFEF) and ice temperature was used to extend the shelf life of Pacific white shrimp (). The...
A novel storage technique that combines the low-frequency electric field (LFEF) and ice temperature was used to extend the shelf life of Pacific white shrimp (). The study investigated the effect of LFEF treatment on the quality and microbial composition of during storage at ice temperature. The results showed that the LFEF treatment significantly extended the shelf life of shrimp during storage at ice temperature. The total volatile base nitrogen (TVB-N) and pH of samples increased over time, while the total viable count (TVC) showed a trend of first decreasing and then increasing. Obviously, shrimp samples treated with LFEF had a lower pH, TVB-N and TVC values than the untreated samples ( < 0.05) at the middle and late stages of storage. LFEF treatment increased the diversity and altered the composition of the microbial communities in . Additionally, the treatment led to a decrease in the relative abundance of dominant spoilage bacteria, including , and , in stored at ice temperature for 11 days. Furthermore, correlation analysis indicated that TVB-N and pH had a significant and positive correlation with , suggesting that had a greater impact on shrimp quality. This study supports the practical application of accelerated low-frequency electric field-assisted shrimp preservation as an effective means of maintaining shrimp meat quality.
PubMed: 38672816
DOI: 10.3390/foods13081143 -
BMC Microbiology Apr 2024Vibrio parahaemolyticus is the predominant etiological agent of seafood-associated foodborne illnesses on a global scale. It is essential to elucidate the mechanisms by...
BACKGROUND
Vibrio parahaemolyticus is the predominant etiological agent of seafood-associated foodborne illnesses on a global scale. It is essential to elucidate the mechanisms by which this pathogen disseminates. Given the existing research predominantly concentrates on localized outbreaks, there is a pressing necessity for a comprehensive investigation to capture strains of V. parahaemolyticus cross borders.
RESULTS
This study examined the frequency and genetic attributes of imported V. parahaemolyticus strains among travelers entering Shanghai Port, China, between 2017 and 2019.Through the collection of 21 strains from diverse countries and regions, Southeast Asia was pinpointed as a significant source for the emergence of V. parahaemolyticus. Phylogenetic analysis revealed clear delineation between strains originating from human and environmental sources, emphasizing that underlying genome data of foodborne pathogens is essential for environmental monitoring, food safety and early diagnosis of diseases. Furthermore, our study identified the presence of virulence genes (tdh and tlh) and approximately 120 antibiotic resistance-related genes in the majority of isolates, highlighting their crucial involvement in the pathogenesis of V. parahaemolyticus.
CONCLUSIONS
This research enhanced our comprehension of the worldwide transmission of V. parahaemolyticus and its antimicrobial resistance patterns. The findings have important implications for public health interventions and antimicrobial stewardship strategies, underscoring the necessity for epidemiological surveillance of pathogen at international travel hubs.
Topics: Vibrio parahaemolyticus; Humans; China; Vibrio Infections; Phylogeny; Foodborne Diseases; Genome, Bacterial; Travel; Virulence Factors; Genomics; Drug Resistance, Bacterial; Anti-Bacterial Agents; Seafood
PubMed: 38671363
DOI: 10.1186/s12866-024-03303-7 -
Fish & Shellfish Immunology Jun 2024MicroRNAs are increasingly recognized for their pivotal role in the immune system, yet the specific regulatory functions of fish-derived microRNAs remain largely...
MicroRNAs are increasingly recognized for their pivotal role in the immune system, yet the specific regulatory functions of fish-derived microRNAs remain largely unexplored. In this research, we discovered a novel miRNA, Cse-miR-144, in the Chinese tongue sole (Cynoglossus semilaevis), characterized by a 73-base pair precursor and a 21-nucleotide mature sequence. Our findings revealed that the expression of Cse-miR-144 was notably inhibited by various Vibrio species. Utilizing bioinformatics and dual-luciferase assay techniques, we established that the pro-inflammatory cytokine gene CsMAPK6 is a direct target of Cse-miR-144. Subsequent in vitro and in vivo western blotting analyses confirmed that Cse-miR-144 can effectively reduce the protein levels of CsMAPK6 post-transcriptionally. Moreover, CsMAPK6 is known to be involved in the activation of the Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-kB). Additional investigations using qPCR and ELISA demonstrated that suppression of Cse-miR-144 leads to an upsurge in the liver mRNA levels of various immune genes (including MYD88, TRAF6, NF-κB, TRAF2, TRAF3, and TNF), alongside a marked increase in the production and secretion of pro-inflammatory cytokines (IL-1β, IL-6, and IL-8) in the bloodstream of C. semilaevis. These findings collectively underscore the potential of Cse-miR-144 as a key inhibitor of CsMAPK and its crucial role in modulating the immune and inflammatory responses in teleost fish. Compared to the siRNA, miRNA is a better tool in controlling the expression of target gene with a lower cost.
Topics: Animals; MicroRNAs; Flatfishes; Fish Diseases; Fish Proteins; Vibrio; Immunity, Innate; Gene Expression Regulation; Vibrio Infections; Inflammation; Cytokines
PubMed: 38670413
DOI: 10.1016/j.fsi.2024.109578