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Microbiological Research Apr 2023Aeromonas hydrophila (Ah) is a zoonotic pathogen of great importance to aquaculture and human health. This study systematically evaluated the impact of salinity, sugar,...
Aeromonas hydrophila (Ah) is a zoonotic pathogen of great importance to aquaculture and human health. This study systematically evaluated the impact of salinity, sugar, ammonia nitrogen, and nitric nitrogen levels on the fitness of Ah by using Luria-Bertani (LB) broth supplemented with different concentrations of NaCl, sucrose, NHCl, urea, NaNO or NaNO. Results showed that the static biofilm formation of Ah was higher at 28 °C compared to 37 °C (P < 0.05). At 28 °C, as the NaCl (>1 %) and sucrose levels increased, the Ah biofilm formation and the binding between Ah cells and monoclonal antibodies (mAbs, for immunodetection) decreased. Elevated ammonia nitrogen and nitric nitrogen levels generated no significant impact on Ah biofilm formation or immunodetection (P > 0.05). The expression of mAbs-targeted Omp remained unchanged under high NaCl or sucrose conditions. Further analysis showed that high sucrose conditions led to the over-expression of the extracellular polysaccharides (PS) and promoted the formation of capsule-like structures. These over-expressed PS and capsule structures might be one reason explaining the inhibited immunodetection efficacy. Results generated from this study provide crucial insights for the design of recovery and detection protocols for Ah present in food or environmental samples.
Topics: Humans; Aeromonas hydrophila; Osmotic Pressure; Sodium Chloride; Ammonia; Biofilms; Sucrose
PubMed: 36689842
DOI: 10.1016/j.micres.2023.127301 -
Archives of Virology Jul 2020Aeromonas hydrophila is an important finfish pathogen, besides being an opportunistic human pathogen. In the present study, the genomes of three A. hydrophila-specific...
Aeromonas hydrophila is an important finfish pathogen, besides being an opportunistic human pathogen. In the present study, the genomes of three A. hydrophila-specific phages, CF8, PS1, and PS2, were isolated, characterized and sequenced. Transmission electron microscopy showed that all three phages had typical Myoviridae morphology. The linear dsDNA genomes of CF8, PS1, and PS2 were 238,150 bp, 237,367 bp, and 240,447 bp in length, with a GC content of 42.2%, 38.8%, and 38.8%, respectively. The low sequence similarity (67.6% - 69.8% identity with 27.0% - 29.0% query coverage) to other phage genomes in the NCBI database indicated the novel nature of the CF8, PS1, and PS2 genomes. A total of 244, 247, and 250 open reading frames (ORFs) were predicted in the CF8, PS1, and PS2 genome, respectively. During the annotation process, functional predictions were made for 28-31 ORFs, while the rest were classified as "hypothetical proteins" with yet unknown functions. Genes for tRNAs were also detected in all phage genomes. As all three phages in the present study had a very narrow host range with lytic activity against only one strain of A. hydrophila, these phages could be good candidates for phage typing applications. Moreover, the endolysin- and lytic-transglycosylase-encoding genes could be used for recombinant cloning and expression of anti-microbial proteins.
Topics: Aeromonas hydrophila; Bacteriophages; Base Composition; Base Sequence; Genome, Viral; Host Specificity; Myoviridae; Open Reading Frames; Phylogeny
PubMed: 32356184
DOI: 10.1007/s00705-020-04644-0 -
Frontiers in Immunology 2022In China, channel catfish () is an important aquaculture species; however, haemorrhagic disease ( induced disease) in these fish has caused tremendous economic loss due...
In China, channel catfish () is an important aquaculture species; however, haemorrhagic disease ( induced disease) in these fish has caused tremendous economic loss due to high morbidity and mass mortality in the breeding industry. The role of cortisol in bacterial diseases, particularly in the acute phase, remains unclear. In this study, liver transcriptome (RNA-seq) and chromatin accessibility (ATAC-seq) analyses were employed to investigate the early functional role of cortisol in -stimulated responses. Our experiments confirmed that infection can initially significantly increase serum cortisol levels at 1 h after infection. At this time point, the increased serum cortisol levels can significantly regulate -regulated genes by affecting both transcriptome and chromatin accessibility. Cross-analysis of RNA-seq and ATAC-seq revealed that a certain gene group (92 target_DEGs) was regulated at an early time point by cortisol. KEGG enrichment analysis revealed that the top three pathways according to target_DEGs were cancer, glutathione metabolism, and the Notch signalling pathway. The protein-protein interaction analysis of target_DEGs revealed that they may be primarily involved in cell proliferation, CD8 T cell function, glutathione synthesis, and activation of the NF-κB signalling pathway. This suggests that after the emergence of immune stress, the early regulation of cortisol is positive against the immune response. It is possible that in this situation, the animal is attempting to avoid dangerous situations and risks and then cope with the imbalance produced by the stressor to ultimately restore homeostasis. Our results will contribute to future research on fish and provide valuable insight regarding the mechanism of immune regulation by cortisol and the study of bacterial haemorrhagic disease in channel catfish.
Topics: Animals; Aeromonas hydrophila; Hydrocortisone; Transcriptome; Chromatin; Gram-Negative Bacterial Infections; Fish Diseases; Ictaluridae; Liver; Glutathione
PubMed: 36532002
DOI: 10.3389/fimmu.2022.989075 -
Fish & Shellfish Immunology Mar 2024Aeromonas hydrophila (A. hydrophila) is a typical zoonotic pathogenic bacterium that infects humans, animals, and fish. It has been reported that the Fur, a Fe...
Aeromonas hydrophila (A. hydrophila) is a typical zoonotic pathogenic bacterium that infects humans, animals, and fish. It has been reported that the Fur, a Fe regulatory protein, and the Crp, a cAMP receptor protein, play important roles in bacterial virulence in many bacteria, but no research has been investigated on A. hydrophila. In this study, the Δfur and Δcrp mutant strains were constructed by the suicide plasmid method. These two mutant strains exhibited a slightly diminished bacterial growth and also were observed some alterations in the number of outer membrane proteins, and the disappearance of hemolysis in the Δcrp strain. Animal experiments of crucian carp showed that the Δfur and Δcrp mutant strains significantly decreased virulence compared to the wild-type strain, and both mutant strains were able to induce good immune responses by two kinds of administration routes of intraperitoneal immunization (i.p) and immersion immunization, and the protection rates through intraperitoneal injection of Δfur and Δcrp to crucian carp were as high as 83.3 % and 73.3 %, respectively, and immersion immunization route of Δfur and Δcrp to crucian carp provided protection as high as 40 % and 20 %, respectively. These two mutant strains showed abilities to induce changes in enzymatic activities of the non-specific enzymes SOD, LZM, AKP, and ACP in crucian carp. Together, these results indicated the Δfur and Δcrp mutants were safe and effective candidate vaccine strains, showing good protection against the wild-type A. hydrophila challenge.
Topics: Humans; Animals; Gram-Negative Bacterial Infections; Vaccines, Attenuated; Aeromonas hydrophila; Fish Diseases; Carps
PubMed: 38244821
DOI: 10.1016/j.fsi.2024.109380 -
International Journal of Biological... Dec 2023This study was conducted to elucidate the effects of FOS that alleviate Aeromonas hydrophila-induced intestinal damage. The results showed that A. hydrophila disrupted...
This study was conducted to elucidate the effects of FOS that alleviate Aeromonas hydrophila-induced intestinal damage. The results showed that A. hydrophila disrupted the intestinal structure and increased intestinal permeability, causing abnormalities in mucosal pathology. Additionally, A. hydrophila induced an imbalance in the intestinal flora and disturbed its stability. Dietary FOS ameliorated the injury to the intestinal structure of fish, but also in part improved the condition of the intestinal tight junction complex. Transcriptomic analysis showed that 120 genes were up-regulated and 320 genes were down-regulated. The intestinal immune network for the IgA production signalling pathway was enriched following A. hydrophila infection, and the change in the FOS group was mainly in the Tight junction signalling pathway. Similarly, dietary FOS reduced the disruption of the intestinal microbiota induced by A. hydrophila and improved the intestinal microbiota's stability; FOS was also partially implicated in the upregulation of Tight junction and Adhesion junction pathways by transcriptomic analysis. After further analysis, it was found that fish fed FOS had upregulated expression of genes related to apoptosis, antigen presentation, and the T-cell-mediated immune response in the intestine compared with those in the A. hydrophila group, which may be related to changes in the intestinal microbiome.
Topics: Animals; RNA, Ribosomal, 16S; Aeromonas hydrophila; Intestines; Carps; Cypriniformes; Gene Expression Profiling; Fish Diseases
PubMed: 37742888
DOI: 10.1016/j.ijbiomac.2023.127040 -
Biochemical and Biophysical Research... Jul 2021Protein lysine propionylation (Kpr) modification is a novel post-translational modification (PTM) of prokaryotic cells that was recently discovered; however, it is not...
Protein lysine propionylation (Kpr) modification is a novel post-translational modification (PTM) of prokaryotic cells that was recently discovered; however, it is not clear how this modification regulates bacterial life. In this study, the protein Kpr modification profile in Aeromonas hydrophila was identified by high specificity antibody-based affinity enrichment combined with high resolution LC MS/MS. A total of 98 lysine-propionylated peptides with 59 Kpr proteins were identified, most of which were associated with energy metabolism, transcription and translation processes. To further understand the role of Kpr modified proteins, the K168 site on malate dehydrogenase (MDH) and K608 site on acetyl-coenzyme A synthetase (AcsA) were subjected to site-directed mutation to arginine (R) and glutamine (Q) to simulate deacylation and propionylation, respectively. Subsequent measurement of the enzymatic activity showed that the K168 site of Kpr modification on MDH may negatively regulate the MDH enzymatic activity while also affecting the survival of mdh derivatives when using glucose as the carbon source, whereas Kpr modification of K608 of AcsA does not. Overall, the results of this study indicate that protein Kpr modification plays an important role in bacterial biological functions, especially those involved in the activity of metabolic enzymes.
Topics: Aeromonas hydrophila; Bacterial Proteins; Carbon; Gene Expression Regulation, Enzymologic; Glucose; Lysine; Malate Dehydrogenase; Models, Molecular; Peptides; Propionates; Recombinant Proteins
PubMed: 34030039
DOI: 10.1016/j.bbrc.2021.05.050 -
Fish & Shellfish Immunology Mar 2020Ghrelin is a peptide hormone secreted by gastrointestinal tract which regulates multiple physiological processes such as appetite, metabolism, growth and gonad...
Ghrelin is a peptide hormone secreted by gastrointestinal tract which regulates multiple physiological processes such as appetite, metabolism, growth and gonad development in fish. In the present study, the effects of ghrelin on hybrid tilapia infected with Aeromonas hydrophila are elucidated. Juvenile hybrid tilapia fish (20.0 ± 5.0 g) were intraperitoneally injected with 0, 0.1, 1.0, or 10.0 ng/g ghrelin/body weight synthetic ghrelin alone or in combination with A. hydrophila (0.5 × 10 CFU). At 10 days post treatment, the survival rate in the group that received 1.0 ng/g ghrelin/body weight ghrelin in combination with A. hydrophila was higher (66.66%) than that of the Ah group (13.33%) that received A. hydrophila alone. In tilapia that received ghrelin injections, reactive oxygen species (ROS) levels tended to increase at 5 h, while injection of 10.0 ng/g ghrelin/body weight ghrelin resulted in a significant decrease in ROS levels at 10 h. No changes in serum immune or antioxidant-related indicators were observed in fish injected with A. hydrophila compared to controls. However, ghrelin injection decreased Albumin (ALB), glutathione peroxidase (GSH-Px), lysozyme (LZM) and superoxide dismutase (SOD). Histological analysis showed that ghrelin injection alleviated the pathological changes in liver and spleen caused by A. hydrophila infection. Overall, the expression of HSP70, IL-1β, and TGF-β in the liver tended to upregulate compared to the control. In the kidney, HSP70, IL-1β and TGF-β levels were increased, and TNF-α expression levels were decreased compared to the control. The HSP70 level in the spleen was decreased, and IL-1β, TGF-β, and TNF-α were expressed at significantly higher levels in the spleen in the tilapia that received ghrelin injections. Taken together, our results indicate that injection with 1.0 ng/g ghrelin/body weight ghrelin may effectively protect juvenile hybrid tilapia against A. hydrophila infection by improving hematological indicators, maintaining normal histology and regulating cytokine gene expression.
Topics: Aeromonas hydrophila; Animals; Cichlids; Disease Resistance; Dose-Response Relationship, Drug; Fish Diseases; Ghrelin; Gram-Negative Bacterial Infections; Immunity, Innate; Random Allocation
PubMed: 31911288
DOI: 10.1016/j.fsi.2020.01.006 -
Journal of Fish Diseases Dec 2023Aeromonas hydrophila and A. veronii are widespread and important critical pathogenic bacteria in the aquaculture industry and cause severe economic damage. At present,...
Aeromonas hydrophila and A. veronii are widespread and important critical pathogenic bacteria in the aquaculture industry and cause severe economic damage. At present, magnolol has been proved to be a broad-spectrum antibacterial activity, such as A. hydrophila, Staphylococcus aureus and Streptococcus mutans. In order to explore the cause of in vivo disease resistance of magnolol and promote its safe application in aquaculture, the pathological detection and changes in immune indicators of fish after feeding with magnolol were conducted in this paper. Results showed that the diets supplemented with magnolol (3 g magnolol/kg commercial feed) significantly increase the expression level of anti-inflammatory cytokines (IL-10, TGF-β and IL-4) in the liver of goldfish (p < .05). Additionally, the expression levels of proinflammatory cytokines (IL-1β, IL-8 and IFN-γ) did not increase significantly. Subsequently, this study investigated the resistance of goldfish to A. hydrophila and A. veronii infection after feeding with magnolol. The results showed that the survival rates of treatment groups fed 3 g magnolol/kg commercial feed daily increased by 23.1% and 38.5% after 10 days post A. hydrophila and A. veronii (p = .0351) infection, respectively. Meanwhile, growth performance (body weight and length), major internal organs (liver, spleen, kidney and intestine) and the serum biochemistry indicators (ATL and AST) all exhibited no significant adverse effects after the goldfish fed with magnolol for 30 days. TP showed an increasing concentration in the treatment group (p < .05). Results of the mRNA expression of stress response indicated that the expression level of cyp1a and hsp70 was significantly down-regulated after a 30-day treatment (p < .05), and the two genes recovered to the similar level as the control group after a commercial feed diet. In brief, the diets supplemented with magnolol protected the host from the excessive immune response caused by A. hydrophila and A. veronii via enhancing its anti-inflammatory capacity and had no adverse effects with feeding.
Topics: Animals; Goldfish; Aeromonas hydrophila; Gram-Negative Bacterial Infections; Fish Diseases; Diet; Disease Resistance; Cytokines; Animal Feed; Aeromonas veronii
PubMed: 37705318
DOI: 10.1111/jfd.13859 -
Surgical Infections Apr 2022Monomicrobial necrotizing fasciitis caused by , , and are often associated with high mortality rates. The purpose of this study was to compare the independent...
Monomicrobial necrotizing fasciitis caused by , , and are often associated with high mortality rates. The purpose of this study was to compare the independent predictors related to outcomes between and species necrotizing fasciitis. Monomicrobial necrotizing fasciitis caused by (60 patients) and species (31 patients) over an 11-year period were reviewed retrospectively. Differences in mortality, patient characteristics, clinical presentations, and laboratory data were compared between the and species groups, and between the death and the survival subgroups of patients with species. Six patients in the group (10%) and 11 in the species group (32.3%) died. Fifty-nine patents had bacteremia and 16 patients died (27.1%). Patients who had had a higher incidence of bacteremia. The patients who had species presenting with bacteremia were significantly associated with death. The death subgroup of patients with necrotizing fasciitis had a higher incidence of bacteremia, higher counts of banded leukocytes, lower platelet counts, lower total lymphocyte counts, and lower serum albumin level than the survival subgroup. Monomicrobial necrotizing fasciitis caused by species was characterized by more fulminating and higher mortality than that of , even after early fasciotomy and third-generation cephalosporin antibiotic therapy. Those risk factors, such as bacteremia, shock, lower platelet counts, lower albumin levels, and antibiotic resistance were associated with mortality, which should alert clinicians to pay more attention to and aggressively treat those patients with and necrotizing fasciitis.
Topics: Aeromonas; Aeromonas hydrophila; Fasciitis, Necrotizing; Humans; Retrospective Studies; Sepsis; Treatment Outcome; Vibrio Infections; Vibrio vulnificus
PubMed: 35180367
DOI: 10.1089/sur.2021.337 -
Molecular phylogeny, structure modeling and screening of putative inhibitors of aerolysin of EUS112.Journal of Biomolecular Structure &... 2022a Gram-negative bacterium, causes diseases in fish, resulting in excessive loss to the aquaculture industry. is a highly heterogeneous group of bacteria, and the...
a Gram-negative bacterium, causes diseases in fish, resulting in excessive loss to the aquaculture industry. is a highly heterogeneous group of bacteria, and the heterogeneity of the genus is attributed to variation and diversity in the virulence factors and toxins among various strains. One of the major toxins aerolysin, secreted by the bacterium, causes hemorrhagic-septicemia and diarrhea and can serve as a drug target. Here, we describe characterization, molecular phylogeny, and homology modeling of the aerolysin of strain EUS112 () cloned in our lab. The encoded aerolysin is 485 amino acids long with an N-terminal signal sequence of 23 amino acids. Phylogenetic analysis of the aerolysin of revealed that it belongs to a diverse group of toxins, showing maximum similarity with aerolysins of other strains followed by toxin. The homology model of the mature aerolysin of was generated using the crystal structure of a mutant aerolysin (PDB#3g4n) as the template, which showed that the encoded aerolysin exists as a channel protein. Validation of the generated model using bioinformatics tool confirmed it to be a good quality model that can be used for drug design. Molecular dock analysis revealed that drugs, aralia-saponin I, cyclamin, ardisiacrispin B, and aralia-saponin II bind to aerolysin with a higher affinity as compared to other drugs and at functionally important amino acids of aerolysin. Hence, these molecules can act as an effective therapeutics for inhibiting the aerolysin pore formation and curtail the severity of infection.Communicated by Ramaswamy H. Sarma.
Topics: Animals; Aeromonas hydrophila; Phylogeny; Aeromonas; Virulence Factors; Amino Acids
PubMed: 33931004
DOI: 10.1080/07391102.2021.1918254