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PeerJ 2023Biofloc technology improves water quality and promote the growth of beneficial bacteria community in shrimp culture. However, little is known about the bacteria...
Biofloc technology improves water quality and promote the growth of beneficial bacteria community in shrimp culture. However, little is known about the bacteria community structure in both water and gut of cultured organisms. To address this, the current study characterised the metagenomes derived from water and shrimp intestine samples of novel Rapid BFT with probiotic and clearwater treatments using 16S V4 region and full length 16S sequencing. Bacteria diversity of water and intestine samples of Rapid BFT and probiotic treatments were similar. Based on the 16S V4 region, water samples of >20 μm biofloc had the highest abundance of amplicon sequence variant (ASV). However, based on full length 16S, no clear distinction in microbial diversity was observed between water samples and intestine samples. Proteobacteria was the most abundant taxon in all samples based on both 16S V4 and full length 16S sequences. was among the highest genus based on 16S V4 region but only full length 16S was able to discern up to species level, with three s identified-, and . being the most abundant species in all treatments. Among water samples, biofloc water samples had the lowest abundance of all three s, with was present only in bioflocs of <20 μm. Predicted functional profiles of treatments support the beneficial impacts of probiotic and biofloc inclusion into shrimp culture system. This study highlights the potential displacement of opportunistic pathogens by the usage of biofloc technology (Rapid BFT) in shrimp culture.
Topics: Animals; Metagenome; Penaeidae; Seafood; Aquaculture; Probiotics
PubMed: 37790619
DOI: 10.7717/peerj.15758 -
Organic Letters Oct 2023Herein, we report the total synthesis of a linear, conjugation-ready, tetrasaccharide repeating unit of MO6-24, which is composed of rare amino sugars such as...
Herein, we report the total synthesis of a linear, conjugation-ready, tetrasaccharide repeating unit of MO6-24, which is composed of rare amino sugars such as l-quinovosamine and d-galactosamine uronic acid. The key challenges addressed here are the synthesis of rare deoxy amino sugars, installation of consecutive 1,2- glycosidic linkages, and late-stage oxidation. Total synthesis of the target molecule was completed via a longest linear sequence of 29 steps in an overall yield of 0.7% starting from l-rhamnose.
PubMed: 37756139
DOI: 10.1021/acs.orglett.3c02872 -
NPJ Vaccines Sep 2023Flagellin, the TLR5 agonist, shows potent adjuvant activities in diverse vaccines and immunotherapies. Vibrio vulnificus flagellin B expressed in eukaryotic cells...
Flagellin, the TLR5 agonist, shows potent adjuvant activities in diverse vaccines and immunotherapies. Vibrio vulnificus flagellin B expressed in eukaryotic cells (eFlaB) could not stimulate TLR5 signaling. Enzymatic deglycosylation restored eFlaB's TLR5 stimulating functionality, suggesting that glycosylation interferes with eFlaB binding to TLR5. Site-directed mutagenesis of N-glycosylation residues restored TLR5 stimulation and adjuvanticity. Collectively, deglycosylated eFlaB may provide a built-in adjuvant platform for eukaryotic-expressed antigens and nucleic acid vaccines.
PubMed: 37752138
DOI: 10.1038/s41541-023-00738-3 -
JAMA Oct 2023
Topics: Humans; Centers for Disease Control and Prevention, U.S.; United States; Vibrio Infections; Vibrio vulnificus
PubMed: 37728946
DOI: 10.1001/jama.2023.17816 -
Journal of Cellular Physiology Oct 2023Vibrio vulnificus, a gram-negative bacterium, causes serious wound infections and septicemia. Once it develops into early phase sepsis, hyperinflammatory immune...
Vibrio vulnificus, a gram-negative bacterium, causes serious wound infections and septicemia. Once it develops into early phase sepsis, hyperinflammatory immune responses result in poor prognosis in patients. The present study aimed to examine the possible underlying pathogenic mechanism and explore potential agents that could protect against V. vulnificus cytotoxicity. Here, we report that infection of mouse macrophages with V. vulnificus triggers antiphagocytic effects and pyroptotic inflammation via ATP-mediated purinergic P2X7 receptor (P2X7R) signaling. V. vulnificus promoted P2X7-dependent nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65 translocation, modulating the expression of the inflammasome sensor NLR family pyrin domain containing 3 (NLRP3), adaptor apoptosis-associated speck-like protein containing a card (ASC), and pyroptotic protein gasdermin D (GSDMD) in mouse macrophages. V. vulnificus induced the NLRP3/caspase-1 inflammasome signaling complex expression that drives GSDMD transmembrane pore formation and secretion of interleukin (IL)-1β, IL-18, and macrophage inflammatory protein-2 (MIP-2). This effect was blocked by P2X7R antagonists, indicating that the P2X7R mediates GSDMD-related pyroptotic inflammation in macrophages through the NF-κB/NLRP3/caspase-1 signaling pathway. Furthermore, blockade of P2X7R reduced V. vulnificus-colony-forming units in the spleen, immune cell infiltration into the skin and lung tissues, and serum concentrations of IL-1β, IL-18, and MIP-2 in mice. These results indicate that P2X7R plays a vital role in mediating phagocytosis by macrophages and pyroptotic inflammation during V. vulnificus infection and provides new opportunities for therapeutic intervention in bacterial infections.
PubMed: 37724600
DOI: 10.1002/jcp.31114 -
Frontiers in Cellular and Infection... 2023, a foodborne pathogen, has a high mortality rate. Despite its relevance to public health, the identification of virulence genes associated with the pathogenicity of...
, a foodborne pathogen, has a high mortality rate. Despite its relevance to public health, the identification of virulence genes associated with the pathogenicity of currently known clinical isolates of is incomplete and its synergistic pathogenesis remains unclear. Here, we integrate whole genome sequencing (WGS), genome-wide association studies (GWAS), and genome-wide epistasis studies (GWES), along with phenotype characterization to investigate the pathogenesis and survival strategies of . GWAS and GWES identified a total of six genes (, , , , , and ) associated with the pathogenicity of clinical isolates related to nucleotide/amino acid transport and metabolism, cell membrane biogenesis, signal transduction mechanisms, and protein turnover. Of these, five were newly discovered potential specific virulence genes of in this study. Furthermore, GWES combined with phenotype experiments indicated that isolates were clustered into two ecological groups (EGs) that shared distinct biotic and abiotic factors, and ecological strategies. Our study reveals pathogenic mechanisms and their evolution in to provide a solid foundation for designing new vaccines and therapeutic targets.
Topics: Metagenomics; Vibrio vulnificus; Genome-Wide Association Study; Amino Acids; Biological Transport
PubMed: 37692161
DOI: 10.3389/fcimb.2023.1254379 -
Fish & Shellfish Immunology Oct 2023Thymosin beta-4 (Tβ4) is a ubiquitous protein with multiple and diverse intracellular and extracellular functions in vertebrates, which play fundamental roles in innate...
Thymosin beta-4 (Tβ4) is a ubiquitous protein with multiple and diverse intracellular and extracellular functions in vertebrates, which play fundamental roles in innate immune against pathogens and wound healing. In this study, the full-length cDNA of Tβ4 was cloned from Penaeus monodon (designated as PmTβ4), using the technology of rapid amplification of cDNA ends (RACE). The cDNA of PmTβ4 was 1361 bp with an open reading frame (ORF) of 501 bp, which encoding a polypeptide of 166 amino acid. The Quantitative Real-time PCR (qRT-PCR) analysis results showed that PmTβ4 was ubiquitously expressed in all the tested shrimp tissues, with the highest expression level was detected in the hemolymph, while the lowest expression level in the muscle. The expression level of PmTβ4 was significantly up-regulated in hepatopancreas after challenged by Vibrio parahaemolyticus, Vibrio harveyi and Staphylococcus aureus. In vitro antimicrobial test showed that the recombinant protein of PmTβ4 (rPmTβ4) had broad-spectrum of antimicrobial activity, which could inhibit both the growth of gram-negative bacteria and gram-positive bacteria, including Vibrio vulnificus, V. parahaemolyticus, Streptococcus agalactiae, S. aureus and Aeromonas hydrophila. Moreover, rPmTβ4 had a certain binding ability to different bacteria, and this binding ability exhibits a strong dose-dependent effect. In vivo, PmTβ4 could facilitate external bacterial clearance in shrimp, and have beneficial to shrimp survival post V. parahaemolyticus infection. Furthermore, wound-healing assay was carried out to study the role of PmTβ4 in the process of wound healing. The results showed that the PmTβ4 expression was significantly up-regulated by injury treatment, and exerted positive effects to promote wound healing. In addition, PmTβ4 can significantly increase the expression level of superoxide dismutase (SOD) and Catalase (CAT) after injury treatment in shrimp, which would involve in scavenging reactive oxygen species (ROS) caused by the wound. In conclusion, these results indicated that PmTβ4 may play important roles in antibacterial immunity and wound healing in Penaeus monodon.
Topics: Animals; Penaeidae; DNA, Complementary; Staphylococcus aureus; Amino Acid Sequence; Immunity, Innate; Vibrio parahaemolyticus; Anti-Bacterial Agents; Arthropod Proteins
PubMed: 37689229
DOI: 10.1016/j.fsi.2023.109065 -
Journal of Agricultural and Food... Sep 2023Marine fungus-derived natural products are an important source of antimicrobial compounds against marine aquatic pathogens. Here, we describe the isolation and...
Marine fungus-derived natural products are an important source of antimicrobial compounds against marine aquatic pathogens. Here, we describe the isolation and characterization of five new pentadepsipeptides, aspertides A-E (-), containing a unique -methoxycinnamoyl amide group, from the marine fungi MA-21 and SD-512. Among them, aspertides B-E (-) also possessed uncommon amino acid residues, such as 3-hydroxyproline, 2,3-dihydroxyproline, or pipecolinic acid. The structures of these compounds were elucidated on the basis of NMR and mass spectroscopic analyses. The absolute configurations of them were established by chiral HPLC analyses of the acidic hydrolysates and NMR calculations with DP4+ probability analysis. In bio-activity assays, compounds and exhibited antibacterial activities against aquatic-pathogenic bacteria, including , , , and with MIC values of 8-32 μg/mL.
Topics: Aspergillus; Anti-Infective Agents; Amides
PubMed: 37650146
DOI: 10.1021/acs.jafc.3c02610 -
Frontiers in Microbiology 2023is a multi-host pathogenic species currently subdivided into five phylogenetic lineages (L) plus one pathovar with the ability to infect fish due to a transmissible...
is a multi-host pathogenic species currently subdivided into five phylogenetic lineages (L) plus one pathovar with the ability to infect fish due to a transmissible virulence plasmid. This plasmid (or a fragment of it) has been transmitted between lineages within the species, contributing to the evolution of . This study aimed to provide an experimental approximation to the mutation rate by determining spontaneous mutation rates from bacterial cultures of representants of the different lineages by whole-genome sequencing. To this purpose, synonymous SNP differences, i.e., spontaneous mutation not subjected to the evolutive forces, between initial and final culture after serial growth were evaluated and used for mutation rate calculation.
PubMed: 37621400
DOI: 10.3389/fmicb.2023.1223293 -
Access Microbiology 2023The stressosome is a protein complex that senses environmental stresses and mediates the stress response in several Gram-positive bacteria through the activation of the...
The stressosome is a protein complex that senses environmental stresses and mediates the stress response in several Gram-positive bacteria through the activation of the alternative sigma factor SigB. The stressosome locus is found in 44 % of Gram-negative isolates. However, does not possess SigB. Nonetheless, in nutrient-limited media, the stressosome modulates gene transcription and bacterial behaviour. In this work, the expression of the stressosome genes was proven during stationary phase in nutrient-rich media and co-transcription as one operonic unit of the stressosome locus and its putative downstream regulatory locus was demonstrated. The construction of a stressosome mutant lacking the genes encoding the four proteins constituting the stressosome complex (VvRsbR, VvRsbS, VvRsbT, VvRsbX) allowed us to examine the role of this complex . Extensive phenotypic characterization of the ΔRSTX mutant in nutrient-rich media showed that the stressosome does not contribute to growth of . Moreover, the stressosome did not modulate the tolerance or survival response of to the range of stresses tested, which included ethanol, hyperosmolarity, hypoxia, high temperature, acidity and oxidative stress. Furthermore, the stressosome was dispensable for motility and exoenzyme production of in nutrient-rich media. Therefore, in conclusion, although stressosome gene transcription occurs in nutrient-rich media, the stressosome neither has an essential role in stress responses of nor does it seem to modulate these activities in these conditions. We hypothesise that the stressosome is expressed in nutrient-rich conditions as a sensor complex, but that activation of the complex does not occur in this environment.
PubMed: 37601438
DOI: 10.1099/acmi.0.000523.v4