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MBio Feb 2024Many pathogenic Gram-negative bacteria use repeats-in-toxin adhesins for colonization and biofilm formation. In the cholera agent , flagellar-regulated hemagglutinin A...
Many pathogenic Gram-negative bacteria use repeats-in-toxin adhesins for colonization and biofilm formation. In the cholera agent , flagellar-regulated hemagglutinin A (FrhA) enables these functions. Using bioinformatic analysis, a sugar-binding domain was identified in FrhA adjacent to a domain of unknown function. AlphaFold2 indicated the boundaries of both domains to be slightly shorter than previously predicted and assisted in the recognition of the unknown domain as a split immunoglobulin-like fold that can assist in projecting the sugar-binding domain toward its target. The AlphaFold2-predicted structure is in excellent agreement with the molecular envelope obtained from small-angle X-ray scattering analysis of a recombinant construct spanning the sugar-binding and unknown domains. This two-domain construct was probed by glycan micro-array screening and showed binding to mammalian fucosylated glycans, some of which are characteristic erythrocyte markers and intestinal cell epitopes. Isothermal titration calorimetry further showed the construct-bound l-fucose with a of 21 µM. Strikingly, this recombinant protein construct bound and lysed erythrocytes in a concentration-dependent manner, and its hemolytic activity was blocked by the addition of l-fucose. A protein ortholog construct from was also produced and showed a similar glycan-binding pattern, binding affinity, erythrocyte-binding, and hemolytic activities. As demonstrated here with Hep-2 cells, fucose-based inhibitors of this sugar-binding domain can potentially be developed to block colonization by and other pathogenic bacteria that share this adhesin domain.IMPORTANCEThe bacterium, , which causes cholera, uses an adhesion protein to stick to human cells and begin the infection process. One part of this adhesin protein binds to a particular sugar, fucose, on the surface of the target cells. This binding can lead to colonization and killing of the cells by the bacteria. Adding l-fucose to the bacteria before they bind to the human cells can prevent attachment and has promise as a preventative drug to protect against cholera.
Topics: Animals; Humans; Vibrio cholerae; Cholera; Aeromonas veronii; Fucose; Adhesins, Bacterial; Polysaccharides; Toxins, Biological; Sugars; Mammals
PubMed: 38171003
DOI: 10.1128/mbio.02291-23 -
IL-6 Mutation Attenuates Liver Injury Caused by Infection by Reducing Oxidative Stress in Zebrafish.International Journal of Molecular... Dec 2023Interleukin-6 (IL-6), a pleiotropic cytokine, plays a crucial role in acute stress induced by bacterial infection and is strongly associated with reactive oxygen species...
Interleukin-6 (IL-6), a pleiotropic cytokine, plays a crucial role in acute stress induced by bacterial infection and is strongly associated with reactive oxygen species (ROS) production. However, the role of IL-6 in the liver of fish after infection remains unclear. Therefore, this study constructed a zebrafish () knockout line by CRISPR/Cas9 to investigate the function of IL-6 in the liver post bacterial infection. After infection with , pathological observation showed that zebrafish exhibited milder liver damage than wild-type (WT) zebrafish. Moreover, liver transcriptome sequencing revealed that 2432 genes were significantly up-regulated and 1706 genes were significantly down-regulated in fish compared with WT fish after infection. Further, gene ontology (GO) analysis showed that differentially expressed genes (DEGs) were significantly enriched in redox-related terms, including oxidoreductase activity, copper ion transport, etc. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that DEGs were significantly enriched in pathways such as the PPAR signaling pathway, suggesting that mutation has a significant effect on redox processes in the liver after infection. Additionally, zebrafish exhibited lower malondialdehyde (MDA) levels and higher superoxide dismutase (SOD) activities in the liver compared with WT zebrafish following infection, indicating that IL-6 deficiency mitigates oxidative stress induced by infection in the liver. These findings provide a basis for further studies on the role of IL-6 in regulating oxidative stress in response to bacterial infections.
Topics: Animals; Aeromonas hydrophila; Bacterial Infections; Gram-Negative Bacterial Infections; Interleukin-6; Liver; Mutation; Oxidation-Reduction; Oxidative Stress; Zebrafish; Zebrafish Proteins; Disease Models, Animal
PubMed: 38139043
DOI: 10.3390/ijms242417215 -
Fish Physiology and Biochemistry Apr 2024In the aquaculture industry, silica nanoparticles (SiNPs) have great significance, mainly for confronting diseases. Therefore, the present study aims to assess the...
Silica nanoparticles alleviate the immunosuppression, oxidative stress, biochemical, behavioral, and histopathological alterations induced by Aeromonas veronii infection in African catfish (Clarias gariepinus).
In the aquaculture industry, silica nanoparticles (SiNPs) have great significance, mainly for confronting diseases. Therefore, the present study aims to assess the antibacterial efficiency of SiNPs as a versatile trial against Aeromonas veronii infection in African catfish (Clarias gariepinus). Further, we investigated the influence of SiNPs in palliating the immune-antioxidant stress biochemical, ethological, and histopathological alterations induced by A. veronii. The experiment was conducted for 10 days, and about 120 fish were distributed into four groups at random, with 30 fish each. The first group is a control that was neither exposed to infection nor SiNPs. The second group (SiNPs) was vulnerable to SiNPs at a concentration of 20 mg/L in water. The third group was experimentally infected with A. veronii at a concentration of 1.5 × 10 CFU/mL. The fourth group (A. veronii + SiNPs) was exposed to SiNPs and infected with A. veronii. Results outlined that A. veronii infection induced behavioral alterations and suppression of immune-antioxidant responses that appeared as a clear decline in protein profile indices, complement 3, lysozyme activity, glutathione peroxidase, and total antioxidant capacity. The kidney and liver function biomarkers (creatinine, urea, alkaline phosphatase, and alanine aminotransferase) and lipid peroxide (malondialdehyde) were substantially increased in the A. veronii group, with marked histopathological changes and immunohistochemical alterations in these tissues. Interestingly, the exposure to SiNPs resulted in a clear improvement in all measured biomarkers and a noticeable regeneration of the histopathological changes. Overall, it will establish that SiNPs are a new, successful tool for opposing immunological, antioxidant, physiological, and histopathological alterations induced by A. veronii infection.
Topics: Animals; Antioxidants; Aeromonas veronii; Catfishes; Oxidative Stress; Immunosuppression Therapy; Biomarkers
PubMed: 38060081
DOI: 10.1007/s10695-023-01274-6 -
Virus Research Jan 2024Aeromonas hydrophila is an opportunistic pathogen that frequently leads to significant mortality in various commercially cultured aquatic species. Bacteriophages offer...
Aeromonas hydrophila is an opportunistic pathogen that frequently leads to significant mortality in various commercially cultured aquatic species. Bacteriophages offer an alternative strategy for pathogens elimination. In this study, we isolated, identified, and characterized a novel temperate A. hydrophila phage, designated as P05B. The bacteriophage P05B is a myovirus based on its morphological features, and possesses the capability to lyse A. hydrophila strains isolated from shrimp. The optimal multiplicity of infection (MOI), adsorption rate, latent period, and burst size for phage P05B were determined to be 0.001, 91.7 %, 20 min, and 483 PFU/cell, respectively. Phage P05B displayed stability across a range of temperatures (28-50 °C) and pH values (4.0-10.0). Sequence analysis unveiled that the genome of phage P05B comprises 32,302 base pairs with an average G + C content of 59.4 %. A total of 40 open reading frames (ORF) were encoded within the phage P05B genome. The comparative genomic analyses clearly implied that P05B might represent a novel species of the genus Bielevirus under Peduoviridae family. A phylogenetic tree was reconstructed, demonstrating that P05B shares a close evolutionary relationship with other Aeromonas and Aeromonas phages. In conclusion, this study increased our knowledge about a new temperate phage of A. hydrophila with strong lytic ability.
Topics: Animals; Bacteriophages; Aeromonas hydrophila; Palaemonidae; Larva; Phylogeny; Ponds; Genome, Viral
PubMed: 37992971
DOI: 10.1016/j.virusres.2023.199279 -
BMC Research Notes Nov 2023Eel (Anguilla bicolor bicolor) is an Indonesian export commodity. However, it is facing a problem related to Aeromonas hydrophila, which can cause motile aeromonas...
The potential of shallot skin powder and actinomycetes metabolites as antimicrobe and antibiofilm in the treatment of eel (Anguilla bicolor bicolor) infected with Aeromonas hydrophila.
BACKGROUND
Eel (Anguilla bicolor bicolor) is an Indonesian export commodity. However, it is facing a problem related to Aeromonas hydrophila, which can cause motile aeromonas septicemia (MAS) and produce biofilm formation. Problem with antibiotic resistance challenges the need of an alternative treatment. Therefore, it is important to explore a solution to treat infection and the biofilm formed by A. hydrophila.
OBJECTIVES
In this study, we used shallot skin powder and actinomycetes metabolite 20 PM as antimicrobe and antibiofilm to treated eels infected with A. hydrophila.
RESULTS
Shallot skin powder (6.25 g 100 g feed) and Actinomycetes 20 PM metabolite (2 mL 100 g feed) were found to be effective as antimicrobe and antibiofilm agent in treating eels infected with A. hydrophila. Eel treated with antibiotic, shallot skin powder, and actinomycetes metabolite had 80%, 66%, and 73% survival rates, respectively. Other indicators such as red blood cell count, hemoglobin, and hematocrit were increased, but white blood cell count and phagocytic activity were dropped. Biofilm destruction were analyzed using scanning electron microscopy to determined antibiofilm activity of actinomycetes metabolite against biofilm of A. Hydrophila.
CONCLUSIONS
Shallot skin powder and actinomycetes metabolite were potential to treat infection of A. hydrophila in eel as an alternative treatment to antibiotics.
Topics: Animals; Anguilla; Aeromonas hydrophila; Powders; Shallots; Actinobacteria; Actinomyces; Biofilms; Gram-Negative Bacterial Infections
PubMed: 37946241
DOI: 10.1186/s13104-023-06611-9 -
Journal of Global Antimicrobial... Dec 2023
Topics: Aeromonas caviae; beta-Lactamases; Aeromonas
PubMed: 37918788
DOI: 10.1016/j.jgar.2023.10.020 -
Microbiology Spectrum Dec 2023The has been reported in Central Asia and Europe countries like Afghanistan and France in and strains from animals and patients, respectively. However, there is no...
The has been reported in Central Asia and Europe countries like Afghanistan and France in and strains from animals and patients, respectively. However, there is no record of -carrying strain from the natural environment, and -carrying has not been reported in the Asia Pacific. Here, we report the first known enviromental -carrying in the world from reservoir water in Singapore. We have performed a comprehensive genetic environment alignment and comparison of between our strain and other strains from different countries and sources and found the located on a highly conserved gene cluster. We suggest that environmental strains may act as a hidden reservoir involved in the circulating of . The finding of conserved cluster also suggested the existence of multiple transmission pathways of in the Asia-Pacific region, involving multiple sources and different species.
Topics: Animals; Humans; beta-Lactamases; Aeromonas; Asia; France; Anti-Bacterial Agents; Microbial Sensitivity Tests
PubMed: 37909756
DOI: 10.1128/spectrum.01391-23 -
Frontiers in Immunology 2023As the primary natural barrier that protects against adverse environmental conditions, the skin plays a crucial role in the innate immune response of fish, particularly...
As the primary natural barrier that protects against adverse environmental conditions, the skin plays a crucial role in the innate immune response of fish, particularly in relation to bacterial infections. However, due to the diverse functionality and intricate anatomical and cellular composition of the skin, deciphering the immune response of the host is a challenging task. In this study, single nuclei RNA-sequencing (snRNA-seq) was performed on skin biopsies obtained from Chinese longsnout catfish (), comparing -infected subjects to healthy control subjects. A total of 19,581 single nuclei cells were sequenced using 10x Genomics (10,400 in the control group and 9,181 in the treated group). Based on expressed unique transcriptional profiles, 33 cell clusters were identified and classified into 12 cell types including keratinocyte (KC), fibroblast (FB), endothelial cells (EC), secretory cells (SC), immune cells, smooth muscle cells (SMC), and other cells such as pericyte (PC), brush cell (BC), red blood cell (RBC), neuroendocrine cell (NDC), neuron cells (NC), and melanocyte (MC). Among these, three clusters of KCs, namely, KC1, KC2, and KC5 exhibited significant expansion after infection. Analysis of pathway enrichment revealed that KC1 was primarily involved in environmental signal transduction, KC2 was primarily involved in endocrine function, and KC5 was primarily involved in metabolism. Finally, our findings suggest that neutrophils may play a crucial role in combating infections. In summary, this study not only provides the first detailed comprehensive map of all cell types present in the skin of teleost fish but also sheds light on the immune response mechanism of the skin following infection in Chinese longsnout catfish.
Topics: Animals; Humans; Catfishes; Aeromonas hydrophila; RNA-Seq; Endothelial Cells; Immunity, Innate
PubMed: 37908355
DOI: 10.3389/fimmu.2023.1271466 -
Applied and Environmental Microbiology Nov 2023can adhere to host cells through different adherence factors including outer-membrane proteins (OMPs), lipopolysaccharide (LPS), and pili, but its adherence mechanisms...
can adhere to host cells through different adherence factors including outer-membrane proteins (OMPs), lipopolysaccharide (LPS), and pili, but its adherence mechanisms are still unclear. Here, we evaluated the effect of autoinducer-2 (AI-2) on adherence of and its regulation mechanism. After determination of the promotion effect of AI-2 on adherence, we investigated which adherence factor was regulated by AI-2, and the results show that AI-2 only limits the formation of pili. Among the four distinct pili systems, only the mannose-sensitive hemagglutinin (MSHA) type IV pili genes were significantly downregulated after deficiency of AI-2. MshE, an ATPase belonged to MSHA type IV pilin, was confirmed as c-di-GMP receptor, that can bind with c-di-GMP which is positively regulated by AI-2, and the increase of c-di-GMP can promote the expression of MSHA type IV pili genes and adherence of . Therefore, this study confirms that c-di-GMP positively regulated by AI-2 binds with MshE, then increases the expression of MSHA pili genes, finally promoting adherence of , suggesting a multilevel positive regulatory adhesion mechanism that is responsible for adherence.
Topics: Aeromonas veronii; Hemagglutinins; Mannose; Fimbriae, Bacterial
PubMed: 37902393
DOI: 10.1128/aem.00819-23 -
Antimicrobial Agents and Chemotherapy Nov 2023arbapenemase (VCC-1) is a chromosomal encoded class A carbapenemase thus far reported in environmental isolates. Here, we report the first isolation of a -carrying...
arbapenemase (VCC-1) is a chromosomal encoded class A carbapenemase thus far reported in environmental isolates. Here, we report the first isolation of a -carrying from a clinical sample in Israel. The isolate was resistant to all β-lactam agents, including carbapenems. The was located on a large plasmid. GC content suggests that the origin of the gene is neither nor spp. but an unknown progenitor.
Topics: Aeromonas caviae; Anti-Bacterial Agents; Vibrio cholerae; Microbial Sensitivity Tests; beta-Lactamases; Plasmids; Aeromonas
PubMed: 37889006
DOI: 10.1128/aac.00707-23