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1.
Folia Parasitol (Praha) ; 712024 Jul 29.
Article in English | MEDLINE | ID: mdl-39101756

ABSTRACT

European eel, Anguilla anguilla (Linnaeus) (Elopomorpha: Anguilliformes), is a critically endangered fish of ecological and economic importance, hosting numerous parasites, including myxozoans (Cnidaria). Since its initial discovery in the kidney of European eel, Myxidium giardi Cépède, 1906 has been reported with numerous spore sizes and shapes from various tissues of multiple anguillid species. Morphological variability, wide host and tissue spectrum, and lack of sequence data raised doubts about the conspecificity of reported isolates. Subsequent studies provided 18S rDNA sequences of several isolates from anguillids and other elopiform fish, and demonstrated a split of parasite data into two distinct phylogenetic lineages, one comprising the M. giardi sequence, and the other all species infecting elopiform fishes classified under the recently established genus Paramyxidium Freeman et Kristmundsson, 2018. Myxidium giardi was, however, transferred to this genus as Paramyxidium giardi n. comb. and designated as the type species of the genus. In line with this change, the sequence originally identified as M. giardi was considered to have been incorrectly associated with this species. To shed light on the status of M. giardi originally described by Cépède (1906), we conducted microscopic and molecular examinations of various organs of 24 individuals of European eel, originating from diverse Czech habitats. Through morphometric and molecular analyses, we demonstrated that spore and polar capsule morphology, morphometry and tissue tropism of our European eel kidney parasite isolates matched the features of the original M. giardi description. Our isolates clustered in the lineage encompassing the first published M. giardi sequence. Thus, the originally described M. giardi indeed represents an existing species within the genus Myxidium Bütschli, 1882, which we formally resurrect and redescribe. Due to the morphological and molecular differences between M. giardi and P. giardi of Freeman et Kristmundsson (2018), we additionally rename the latter species as Paramyxidium freemani nom. nov.


Subject(s)
Anguilla , Fish Diseases , Kidney , Myxozoa , Parasitic Diseases, Animal , Phylogeny , Animals , Myxozoa/classification , Myxozoa/genetics , Myxozoa/physiology , Fish Diseases/parasitology , Parasitic Diseases, Animal/parasitology , Kidney/parasitology , Anguilla/parasitology , RNA, Ribosomal, 18S/analysis
2.
BMC Vet Res ; 20(1): 340, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39090695

ABSTRACT

BACKGROUND: Understanding the relationship between resident microbiota and disease in cultured fish represents an important and emerging area of study. Marine gill disorders in particular are considered an important challenge to Atlantic salmon (Salmo salar) aquaculture, however relatively little is known regarding the role resident gill microbiota might play in providing protection from or potentiating different gill diseases. Here, 16S rRNA sequencing was used to examine the gill microbiome alongside fish health screening in farmed Atlantic salmon. Results were used to explore the relationship between microbial communities and gill disease. RESULTS: Microbial community restructuring was observed throughout the sampling period and linked to varied drivers of change, including environmental conditions and severity of gill pathology. Taxa with significantly greater relative abundance on healthier gills included isolates within genus Shewanella, and taxa within family Procabacteriaceae. In contrast, altered abundance of Candidatus Branchiomonas and Rubritalea spp. were associated with damaged gills. Interestingly, more general changes in community richness and diversity were not associated with altered gill health, and thus not apparently deleterious to fish. Gross and histological gill scoring demonstrated seasonal shifts in gill pathology, with increased severity of gill damage in autumn. Specific infectious causes that contributed to observed pathology within the population included the gill disorder amoebic gill disease (AGD), however due to the uncontrolled nature of this study and likely mixed contribution of various causes of gill disease to observed pathology results do not strongly support an association between the microbial community and specific infectious or non-infectious drivers of gill pathology. CONCLUSIONS: Results suggest that the microbial community of farmed Atlantic salmon gills undergo continual restructuring in the marine environment, with mixed influences upon this change including environmental, host, and pathogenic factors. A significant association of specific taxa with different gill health states suggests these taxa might make meaningful indicators of gill health. Further research with more frequent sampling and deliberate manipulation of gills would provide important advancement of knowledge in this area. Overall, although much is still to be learnt regarding what constitutes a healthy or maladapted gill microbial community, the results of this study provide clear advancement of the field, providing new insight into the microbial community structure of gills during an annual production cycle of marine-stage farmed Atlantic salmon.


Subject(s)
Aquaculture , Fish Diseases , Gills , Microbiota , Salmo salar , Animals , Salmo salar/microbiology , Gills/microbiology , Gills/pathology , Fish Diseases/microbiology , Fish Diseases/pathology , RNA, Ribosomal, 16S/genetics , Seasons , Bacteria/classification , Bacteria/isolation & purification , Bacteria/genetics , Amebiasis
3.
Dis Aquat Organ ; 159: 29-35, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39087617

ABSTRACT

The Clinical and Laboratory Standards Institute has published epidemiological cut-off values for susceptibility data generated at 22°°C and read after 44-48 h for florfenicol, oxolinic acid and oxytetracycline against Aeromonas salmonicida. The cut-off values for the minimum inhibitory concentration (MIC) and disc diffusion were derived from data obtained by 1 laboratory and 2 laboratories respectively. The present work reports the generation of susceptibility data from additional laboratories and the calculation of provisional cut-off values from aggregations of these data with previously published data. With respect to MIC data, the provisional cut-off values, derived from aggregations of the data from 4 laboratories, were ≤4 µg ml-1 for florfenicol, ≤0.0625 µg ml-1 for oxolinic acid and ≤1 µg ml-1 for oxytetracycline. For disc diffusion data, the provisional cut-off values derived from aggregations of the data from 5 laboratories were ≥30 mm for florfenicol, ≥32 mm for oxolinic acid and ≥25 mm for oxytetracycline. In addition, a cut-off value of ≥29 mm for ampicillin was derived from the aggregation of data from 4 laboratories.


Subject(s)
Aeromonas salmonicida , Anti-Bacterial Agents , Microbial Sensitivity Tests , Aeromonas salmonicida/drug effects , Anti-Bacterial Agents/pharmacology , Animals , Fish Diseases/microbiology , Gram-Negative Bacterial Infections/veterinary , Gram-Negative Bacterial Infections/microbiology , Gram-Negative Bacterial Infections/epidemiology , Drug Resistance, Bacterial , Thiamphenicol/analogs & derivatives , Thiamphenicol/pharmacology
4.
BMC Vet Res ; 20(1): 361, 2024 Aug 12.
Article in English | MEDLINE | ID: mdl-39129031

ABSTRACT

There is a claimed increase in the global prevalence and incidence of emerging diseases observed in many organisms. Myxozoa represents an essential group of metazoan parasites that hold both economic and ecological significance. In the current study, 1% of the fish population at two commercial goldfish (Carassius auratus) farms in Tehran and Ghom province, Iran, developed cavitating muscular lesions resembling humps in February 2021 and January 2022. Fish displaying pathological abnormalities were transported to the Ornamental Fish Clinic and subjected to clinical examination. Light microscopy was subsequently used to examine wet smears of skin and gills, as well as whitish exudate. In addition, tissue homogenates were collected for more precise identification and molecular confirmation. The study discovered that individuals from the goldfish farms were infected with the pathogenic myxozoan Myxobolus lentisuturalis, which caused significant damage to the epaxial muscles. The spores collected from the humps had a lack of uniformity and were primarily ellipsoidal in shape. Histopathological analysis also revealed parasites in various stages of development, such as plasmodia and spores, as well as inflammatory cell infiltration (macrophage, giant cell and lymphoplasmacytic infiltration) between skeletal muscle fibers. Phylogenetic analysis of M. lentisuturalis was performed by using MEGA 11 and the maximum likelihood method. M. lentisuturalis is a myxozoan parasite that has been sparsely recorded and lacks widespread recognition. The current study is the first clinical, histopathological, and molecular characterization of M. lentisuturalis isolated from the skeletal musculature of goldfish (C. auratus) in Iran.


Subject(s)
Fish Diseases , Goldfish , Myxobolus , Parasitic Diseases, Animal , Phylogeny , Animals , Goldfish/parasitology , Fish Diseases/parasitology , Fish Diseases/pathology , Fish Diseases/epidemiology , Iran/epidemiology , Parasitic Diseases, Animal/parasitology , Parasitic Diseases, Animal/pathology , Parasitic Diseases, Animal/epidemiology , Myxobolus/genetics , Myxobolus/classification , Aquaculture
5.
Front Cell Infect Microbiol ; 14: 1394008, 2024.
Article in English | MEDLINE | ID: mdl-39099884

ABSTRACT

Edwardsiella ictaluri is a Gram-negative, facultative intracellular bacterium that causes enteric septicemia in catfish (ESC). The RNA chaperone Hfq (host factor for phage Qß replication) facilitates gene regulation via small RNAs (sRNAs) in various pathogenic bacteria. Despite its significance in other bacterial species, the role of hfq in E. ictaluri remains unexplored. This study aimed to elucidate the role of hfq in E. ictaluri by creating an hfq mutant (EiΔhfq) through in-frame gene deletion and characterization. Our findings revealed that the Hfq protein is highly conserved within the genus Edwardsiella. The deletion of hfq resulted in a significantly reduced growth rate during the late exponential phase. Additionally, EiΔhfq displayed a diminished capacity for biofilm formation and exhibited increased motility. Under acidic and oxidative stress conditions, EiΔhfq demonstrated impaired growth, and we observed elevated hfq expression when subjected to in vitro and in vivo stress conditions. EiΔhfq exhibited reduced survival within catfish peritoneal macrophages, although it had no discernible effect on the adherence and invasion of epithelial cells. The infection model revealed that hfq is needed for bacterial persistence in catfish, and its absence caused significant virulence attenuation in catfish. Finally, the EiΔhfq vaccination completely protected catfish against subsequent EiWT infection. In summary, these results underscore the pivotal role of hfq in E. ictaluri, affecting its growth, motility, biofilm formation, stress response, and virulence in macrophages and within catfish host.


Subject(s)
Biofilms , Catfishes , Edwardsiella ictaluri , Enterobacteriaceae Infections , Host Factor 1 Protein , Edwardsiella ictaluri/genetics , Edwardsiella ictaluri/pathogenicity , Animals , Host Factor 1 Protein/metabolism , Host Factor 1 Protein/genetics , Biofilms/growth & development , Enterobacteriaceae Infections/microbiology , Catfishes/microbiology , Fish Diseases/microbiology , Virulence , Macrophages/microbiology , Gene Deletion , Gene Expression Regulation, Bacterial , Oxidative Stress , Epithelial Cells/microbiology , Bacterial Adhesion/genetics
6.
Sci Rep ; 14(1): 18006, 2024 08 03.
Article in English | MEDLINE | ID: mdl-39097615

ABSTRACT

Choline is recognized as an essential nutrient for Atlantic salmon at all developmental stages. However, its dietary requirement is not well defined. Choline plays a critical role in lipid transport, and the clearest deficiency sign is intestinal steatosis. The present work, aiming to find whether lipid source and fish size may affect steatosis symptoms, was one of a series of studies conducted to identify which production-related conditions may influence choline requirement. Six choline-deficient diets were formulated varying in ratios of rapeseed oil to fish oil and fed to Atlantic salmon of 1.5 and 4.5 kg. After eight weeks, somatic characteristics were observed, and the severity of intestinal steatosis was assessed by histological, biochemical, and molecular analyses. Fatty acid composition in pyloric intestine, mesenteric tissue, and liver samples was also quantified. The increasing rapeseed oil level increased lipid digestibility markedly, enhancing lipid supply to the fish. Moreover, small fish consumed more feed, and consequently had a higher lipid intake. In conclusion, the results showed that choline requirement depends on dietary lipid load, which depends on the fatty acid profile as well as the fish size.


Subject(s)
Animal Feed , Fish Oils , Rapeseed Oil , Salmo salar , Animals , Rapeseed Oil/administration & dosage , Salmo salar/metabolism , Salmo salar/growth & development , Fish Oils/administration & dosage , Animal Feed/analysis , Fatty Acids/metabolism , Fatty Acids/analysis , Fish Diseases/pathology , Fish Diseases/metabolism , Fatty Liver/veterinary , Fatty Liver/metabolism , Fatty Liver/etiology , Fatty Liver/pathology , Choline/metabolism , Choline/administration & dosage , Diet/veterinary , Liver/metabolism , Liver/pathology
7.
Fish Shellfish Immunol ; 152: 109803, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39096980

ABSTRACT

Nervous necrosis virus (NNV) capsid protein plays an important role in producing viral particles without any genetic elements. Thus, NNV is a promising candidate for vaccine development and is widely used for constructing vaccines, including DNA, recombinant proteins, and virus-like particles (VLPs). Our study aimed to investigate the potential of NNV capsid protein (NNV) and NNV capsid protein fused to enhanced green fluorescent protein (NNV-EGFP) through VLP formation and whether their application can induce specific antibody responses against certain antigens. We focused on producing DNA and recombinant protein vaccines consisting of the genes for NNV, EGFP, and NNV-EGFP. The approach using NNV-EGFP allowed NNV to act as a carrier or inducer while EGFP was incorporated as part of the capsid protein, thereby enhancing the immune response. In vitro studies demonstrated that all DNA vaccines expressed in HINAE cells resulted in varying protein expression levels, with particularly low levels observed for pNNV and pNNV-EGFP. Consequently, structural proteins derived from HINAE cells could not be observed using transmission electron microscopy (TEM). In contrast, recombinant proteins of NNV and NNV-EGFP were expressed through the Escherichia coli expression system. TEM revealed that rNNV was assembled into VLPs with an approximate size of 30 nm, whereas rNNV-EGFP presented particles ranging from 10 nm to 50 nm in size. For the vaccination test, DNA vaccination marginally induced specific antibody responses in Japanese flounder compared to unvaccinated fish. Meanwhile, NNV and NNV-EGFP recombinant vaccines enhanced a greater anti-NNV antibody response than the others, whereas antibody responses against EGFP were also marginal. These results indicate that NNV capsid protein-based antigens, presenting as particles, play an important role in eliciting a specific anti-NNV antibody response and have the potential to improve fish immune responses.


Subject(s)
Capsid Proteins , Fish Diseases , Nodaviridae , Viral Vaccines , Animals , Nodaviridae/immunology , Capsid Proteins/immunology , Capsid Proteins/genetics , Fish Diseases/immunology , Fish Diseases/prevention & control , Viral Vaccines/immunology , Viral Vaccines/administration & dosage , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/immunology , RNA Virus Infections/veterinary , RNA Virus Infections/immunology , RNA Virus Infections/prevention & control , Vaccines, DNA/immunology , Vaccines, DNA/administration & dosage , Vaccine Development , Vaccines, Virus-Like Particle/immunology , Vaccines, Virus-Like Particle/administration & dosage
8.
Fish Shellfish Immunol ; 152: 109802, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39096982

ABSTRACT

Necroptosis is a caspase-independent programmed cell death process characterized by morphological similarities to necrosis and the potential to cause significant inflammatory reactions. The initiation, execution, and inhibition of necroptosis involve a complex interplay of various signaling proteins. When death receptors bind to ligands, necroptosis is triggered through the receptor-interacting serine/threonine-protein kinase 1 (RIPK1)/RIPK3/Mixed Lineage Kinase Domain-Like (MLKL) axis, leading to inflammatory reactions in the surrounding tissues. This process encompasses numerous physiological regulatory mechanisms and contributes to the development and progression of certain diseases. The mechanisms of necroptosis were not well conserved across terrestrial and aquatic organisms, with differences in some components and functions. Given the significant challenges that aquatic animal diseases pose to aquaculture, research interest in necroptosis has surged recently, particularly in studies focusing on fish. Understanding necroptosis in fish can lead to interventions that offer potential breakthroughs in disease inhibition and fish health improvement.


Subject(s)
Fish Diseases , Fishes , Necroptosis , Animals , Necroptosis/immunology , Fish Diseases/immunology , Fish Diseases/prevention & control , Fishes/immunology
9.
Sci Rep ; 14(1): 18341, 2024 08 07.
Article in English | MEDLINE | ID: mdl-39112606

ABSTRACT

Newly synthesized vaccines prepared from formalin-killed bacteria Streptococcus pyogenes were investigated in the current study to evaluate the effectiveness of the newly synthesized vaccine as well as their safety by injected intraperitoneal. The study involved several steps 1st step is the preparation of the vaccine followed by the 2nd step: Evaluate the effectiveness and vaccine safety against pathogenic S. pyogenes through 4 different groups including control (Group I). Group II (Bacterial, infected group), Group III (Vaccine), and the Last group was the challenged group after the vaccination (Vacc + Bac). Different Immunological and biochemical parameters were measured in addition to hematological and histopathological examinations. For example, oxidative/antioxidants, inflammatory biomarkers, fragmentation and cell damage, and finally the histopathological study. The current study showed an increase in all oxidative, inflammatory, and cell damage (DNA fragmentation assays), additionally markedly elevation in histopathological cell damage in the infected group (Group II) compared with the control group. The vaccine and challenged after vaccination group (vaccine + Bacteria), showed great improvement in oxidative biomarkers (LPO) and an increase in antioxidants biomarkers (GSH, SOD, GST, DPPH, ABTS, GR and GPx), Also the inflammation and histopathological examination. The newly synthesized vaccine improved the resistance of Oreochromis niloticus and can be used as a preventive therapy agent for pathogenic bacteria S. pyogenes.


Subject(s)
Cichlids , Liver , Streptococcal Infections , Streptococcal Vaccines , Streptococcus pyogenes , Vaccination , Animals , Streptococcus pyogenes/immunology , Streptococcal Infections/prevention & control , Streptococcal Infections/immunology , Cichlids/immunology , Cichlids/microbiology , Liver/microbiology , Liver/pathology , Liver/metabolism , Vaccination/methods , Streptococcal Vaccines/immunology , Formaldehyde , Vaccines, Inactivated/immunology , Fish Diseases/prevention & control , Fish Diseases/microbiology , Fish Diseases/immunology , Antioxidants/pharmacology , Oxidative Stress/drug effects , Biomarkers
10.
PLoS Pathog ; 20(8): e1012328, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39102417

ABSTRACT

Spring viremia of carp virus (SVCV) has a broad fish host spectrum and is responsible for a disease that generally affects juvenile fishes with a mortality rate of up to 90%. In the absence of treatments or vaccines against SVCV, the search for prophylactic or therapeutic solutions is thus relevant, particularly to identify solutions compatible with mass vaccination. In addition to being a threat to aquaculture and ecosystems, SVCV is a unique pathogen to study virus-host interactions in the zebrafish model. Establishing the first reverse genetics system for SVCV and the design of recombinant SVCV (rSVCV) expressing fluorescent or bioluminescent proteins adds a new dimension for the study of these interactions using innovative imaging techniques. The infection by bath immersion of zebrafish larvae with rSVCV expressing mCherry allows us to define the first SVCV replication sites and the host innate immune responses using different transgenic lines of zebrafish. The fins were found as the main initial sites of infection in both zebrafish and carp, its natural host. Hence, new insights into the physiopathology of SVCV infection have been described. We report that neutrophils are recruited at the sites of infection and persist up to the death of the animal leading to an uncontrolled inflammation correlated with the expression of the pro-inflammatory cytokine IL1ß. Tissue damage was observed at the site of initial replication, a likely consequence of virus-induced injury or the pro-inflammatory response. Interestingly, SVCV infection by bath immersion triggers a persistent pro-inflammatory response rather than activation of the antiviral IFN signaling pathway as observed following intravenous injection, highlighting the importance of the route of infection on the progression of pathogenicity. Thus, this model of zebrafish larvae infection by rSVCV offers new perspectives to study in detail virus-host interactions and to discover new prophylactic or therapeutic solutions.


Subject(s)
Carps , Fish Diseases , Rhabdoviridae Infections , Rhabdoviridae , Zebrafish , Animals , Zebrafish/virology , Rhabdoviridae/physiology , Fish Diseases/virology , Rhabdoviridae Infections/virology , Rhabdoviridae Infections/immunology , Carps/virology , Animals, Genetically Modified , Disease Models, Animal , Immunity, Innate , Viremia
11.
Front Cell Infect Microbiol ; 14: 1425624, 2024.
Article in English | MEDLINE | ID: mdl-39145307

ABSTRACT

Type IV pili (T4P) are versatile proteinaceous protrusions that mediate diverse bacterial processes, including adhesion, motility, and biofilm formation. Aeromonas hydrophila, a Gram-negative facultative anaerobe, causes disease in a wide range of hosts. Previously, we reported the presence of a unique Type IV class C pilus, known as tight adherence (Tad), in virulent Aeromonas hydrophila (vAh). In the present study, we sought to functionalize the role of Tad pili in the pathogenicity of A. hydrophila ML09-119. Through a comprehensive comparative genomics analysis of 170 A. hydrophila genomes, the conserved presence of the Tad operon in vAh isolates was confirmed, suggesting its potential contribution to pathogenicity. Herein, the entire Tad operon was knocked out from A. hydrophila ML09-119 to elucidate its specific role in A. hydrophila virulence. The absence of the Tad operon did not affect growth kinetics but significantly reduced virulence in catfish fingerlings, highlighting the essential role of the Tad operon during infection. Biofilm formation of A. hydrophila ML09-119 was significantly decreased in the Tad operon deletant. Absence of the Tad operon had no effect on sensitivity to other environmental stressors, including hydrogen peroxide, osmolarity, alkalinity, and temperature; however, it was more sensitive to low pH conditions. Scanning electron microscopy revealed that the Tad mutant had a rougher surface structure during log phase growth than the wildtype strain, indicating the absence of Tad impacts the outer surface of vAh during cell division, of which the biological consequences are unknown. These findings highlight the role of Tad in vAh pathogenesis and biofilm formation, signifying the importance of T4P in bacterial infections.


Subject(s)
Aeromonas hydrophila , Biofilms , Fimbriae, Bacterial , Fish Diseases , Gram-Negative Bacterial Infections , Operon , Aeromonas hydrophila/genetics , Aeromonas hydrophila/pathogenicity , Aeromonas hydrophila/physiology , Biofilms/growth & development , Fimbriae, Bacterial/genetics , Fimbriae, Bacterial/metabolism , Virulence/genetics , Animals , Gram-Negative Bacterial Infections/microbiology , Fish Diseases/microbiology , Bacterial Adhesion/genetics , Catfishes/microbiology , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Gene Knockout Techniques
12.
Gene ; 928: 148809, 2024 Nov 30.
Article in English | MEDLINE | ID: mdl-39089532

ABSTRACT

SP3 (specificity protein 3) is a transcription factor characterized by three conserved Cys2His2 zinc finger motifs that exert a transregulatory effect by binding to GC boxes, either upregulating or downregulating multiple genes or by co-regulating gene expression in coordination with other proteins. SP3 potentially regulates a series of processes, such as the cell cycle, growth, metabolic pathways, and apoptosis, and plays an important role in antiviral effect. The function of sp3 in fish is poorly understood. In this study, the Sp3a open reading frame was cloned from the orange-spotted grouper, Epinephelus coioides. The full-length open reading frame of Sp3a was 2034 bp, encoding 677 amino acids, with a predicted molecular weight of 72.34 kDa and an isoelectric point of 5.05. Phylogenetically, Sp3a in Epinephelus coioides was the most closely related to Sp3a in the Malabar grouper, Epinephelus malabaricus. RT-qPCR revealed ubiquitous expression of Sp3a in all examined grouper tissues, with no significant differences in expression levels among tissues. A eukaryotic expression vector, pEGFP-Sp3a, was constructed and transfected into grouper spleen (GS) cells. Subcellular localization of Sp3a was observed using an inverted fluorescence microscope. When Spa3 was overexpressed in GS cells, the expression of orange-spotted grouper nerve necrosis virus (RGNNV) genes (CP and RdRp) decreased significantly, indicating that Sp3a significantly inhibited RGNNV replication. siRNA inhibition of Sp3a accelerated the intracellular replication of RGNNV, implying the antiviral effect of Sp3a. Conclusively, our findings contribute to further research on the antiviral capabilities of Sp3a in grouper and other fish. Therefore, our research has potential implications on the development of the aquaculture industry.


Subject(s)
Bass , Fish Diseases , Fish Proteins , Animals , Fish Diseases/virology , Fish Diseases/genetics , Fish Proteins/genetics , Fish Proteins/metabolism , Bass/genetics , Bass/virology , Sp3 Transcription Factor/metabolism , Sp3 Transcription Factor/genetics , Phylogeny , Nodaviridae/genetics , Cloning, Molecular , RNA Virus Infections/veterinary , RNA Virus Infections/virology , RNA Virus Infections/genetics , DNA Virus Infections/veterinary , DNA Virus Infections/virology , DNA Virus Infections/genetics , Amino Acid Sequence
13.
Zool Res ; 45(5): 990-1000, 2024 Sep 18.
Article in English | MEDLINE | ID: mdl-39147714

ABSTRACT

The von Hippel-Lindau tumor suppressor protein (VHL), an E3 ubiquitin ligase, functions as a critical regulator of the oxygen-sensing pathway for targeting hypoxia-inducible factors. Recent evidence suggests that mammalian VHL may also be critical to the NF-κB signaling pathway, although the specific molecular mechanisms remain unclear. Herein, the roles of mandarin fish ( Siniperca chuatsi) VHL ( scVHL) in the NF-κB signaling pathway and mandarin fish ranavirus (MRV) replication were explored. The transcription of scVHL was induced by immune stimulation and MRV infection, indicating a potential role in innate immunity. Dual-luciferase reporter gene assays and reverse transcription quantitative PCR (RT-qPCR) results demonstrated that scVHL evoked and positively regulated the NF-κB signaling pathway. Treatment with NF-κB signaling pathway inhibitors indicated that the role of scVHL may be mediated through scIKKα, scIKKß, scIκBα, or scp65. Co-immunoprecipitation (Co-IP) analysis identified scIκBα as a novel target protein of scVHL. Moreover, scVHL targeted scIκBα to catalyze the formation of K63-linked polyubiquitin chains to activate the NF-κB signaling pathway. Following MRV infection, NF-κB signaling remained activated, which, in turn, promoted MRV replication. These findings suggest that scVHL not only positively regulates NF-κB but also significantly enhances MRV replication. This study reveals a novel function of scVHL in NF-κB signaling and viral infection in fish.


Subject(s)
Fish Diseases , NF-kappa B , Ranavirus , Signal Transduction , Virus Replication , Animals , NF-kappa B/metabolism , NF-kappa B/genetics , Virus Replication/physiology , Fish Diseases/virology , Ranavirus/physiology , Von Hippel-Lindau Tumor Suppressor Protein/metabolism , Von Hippel-Lindau Tumor Suppressor Protein/genetics , DNA Virus Infections/veterinary , DNA Virus Infections/virology , Fish Proteins/metabolism , Fish Proteins/genetics , I-kappa B Proteins/metabolism , I-kappa B Proteins/genetics , Gene Expression Regulation
14.
Dis Aquat Organ ; 159: 63-69, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39145472

ABSTRACT

All species of the isopod family Cymothoidae are obligate fish parasites, extracting nourishment through hematophagy and tissue consumption. To elucidate the detrimental effects of this parasitic relationship upon the host fish, we examined body length, weight of body, gonad, liver and stomach contents, and condition factor of Japanese scad Decapterus maruadsi infected with the buccal cavity parasite Ceratothoa carinata in different seasons. During the host fish's breeding season in July, the wet weight and condition factor of male and female host fish ages 1 and 2 were conspicuously diminished. No impacts were detected in September, after the breeding season. We found no impact of the parasite on the stomach content weight or signs of prey fish in the stomachs. Thus, parasite infection with C. carinata potentially diminishes the reproductive success of the host fish by negatively impacting the host's physiological condition, particularly during the breeding season.


Subject(s)
Fish Diseases , Isopoda , Reproduction , Animals , Fish Diseases/parasitology , Isopoda/physiology , Female , Male , Host-Parasite Interactions , Seasons , Mouth/parasitology , East Asian People
15.
Dis Aquat Organ ; 159: 79-89, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39145474

ABSTRACT

Piscine francisellosis is one of the most important bacterial diseases affecting various fish species worldwide. Francisella orientalis, F. noatunensis, and F. salimarina (F. marina) have been reported as etiological agents of disease in fish. A Francisella sp. was isolated from several diseased red drum Sciaenops ocellatus experiencing morbidity in Florida, USA, in 2008. In this study, molecular and phenotypic characterization of the recovered isolate was conducted. Phenotypically, the isolate showed a biochemical reaction profile distinct from that of F. orientalis and F. salimarina. Although the 16S rRNA sequence of this isolate shared 99.61% identity to the type strain of F. philomiragia O#319LT, whole genome analysis (average nucleotide identity <95%; digital DNA-DNA hybridization <70%) and a multilocus sequence analysis of 8 concatenated housekeeping genes in comparison with other Francisella spp. indicated that this isolate was a novel Francisella species, more closely related to F. orientalis. Immersion, intracoelomic injection, and co-habitation challenges using a Nile tilapia Oreochromis niloticus fingerling model of infection were done to investigate virulence in a piscine model. Variably pigmented granulomas and pigmented macrophage aggregates were observed in the kidneys and spleens of the challenged fish, but no mortality was recorded during the 15 d challenge period, suggesting that this novel Francisella sp. might be an opportunistic pathogen of fish. Based on the phenotypic and genotypic differences from other Francisella spp. observed in this study, we propose the name Francisella sciaenopsi sp. nov. for this novel isolate.


Subject(s)
Fish Diseases , Francisella , Gram-Negative Bacterial Infections , Phylogeny , Animals , Francisella/genetics , Francisella/classification , Francisella/isolation & purification , Fish Diseases/microbiology , Florida , Gram-Negative Bacterial Infections/veterinary , Gram-Negative Bacterial Infections/microbiology , Cichlids , RNA, Ribosomal, 16S/genetics
16.
Dis Aquat Organ ; 159: 91-97, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39145475

ABSTRACT

Ichthyophonosis is a disease caused by the mesomycetozoean parasite Ichthyophonus hoferi that affects a variety of fish species, including rainbow trout Oncorhynchus mykiss Walbaum. This disease is characterized by granulomatous lesions and necrosis in various organs, which can have severe impacts on the health and welfare of the fish. Ichthyophonosis has been found in several parts of the world, including Europe, and is a significant concern in the aquaculture industry and for populations of wild marine fishes. The rainbow trout is a widely cultured salmonid species in many countries, including Serbia. Although the presence of I. hoferi in rainbow trout has been reported in several countries, it has never been documented in Serbia. In this article, we report the first case of ichthyophonosis in rainbow trout in Serbia.


Subject(s)
Aquaculture , Fish Diseases , Mesomycetozoea Infections , Mesomycetozoea , Oncorhynchus mykiss , Animals , Fish Diseases/parasitology , Fish Diseases/epidemiology , Serbia/epidemiology , Mesomycetozoea Infections/epidemiology , Mesomycetozoea Infections/parasitology , Mesomycetozoea/isolation & purification
17.
Vet Res ; 55(1): 102, 2024 Aug 16.
Article in English | MEDLINE | ID: mdl-39152462

ABSTRACT

In Chile, Piscirickettsia salmonis contains two genetically isolated genogroups, LF-89 and EM-90. However, the impact of a potential co-infection with these two variants on Salmonid Rickettsial Septicemia (SRS) in Atlantic salmon (Salmo salar) remains largely unexplored. In our study, we evaluated the effect of P. salmonis LF-89-like and EM-90-like co-infection on post-smolt Atlantic salmon after an intraperitoneal challenge to compare changes in disease dynamics and host immune response. Co-infected fish had a significantly lower survival rate (24.1%) at 21 days post-challenge (dpc), compared with EM-90-like single-infected fish (40.3%). In contrast, all the LF-89-like single-infected fish survived. In addition, co-infected fish presented a higher presence of clinical lesions than any of the single-infected fish. The gene expression of salmon immune-related biomarkers evaluated in the head kidney, spleen, and liver showed that the EM-90-like isolate and the co-infection induced the up-regulation of cytokines (e.g., il-1ß, ifnγ, il8, il10), antimicrobial peptides (hepdicin) and pattern recognition receptors (PRRs), such as TLR5s. Furthermore, in serum samples from EM-90-like and co-infected fish, an increase in the total IgM level was observed. Interestingly, specific IgM against P. salmonis showed greater detection of EM-90-like antigens in LF-89-like infected fish serum (cross-reaction). These data provide evidence that P. salmonis LF-89-like and EM-90-like interactions can modulate SRS disease dynamics in Atlantic salmon, causing a synergistic effect that increases the severity of the disease and the mortality rate of the fish. Overall, this study contributes to achieving a better understanding of P. salmonis population dynamics.


Subject(s)
Coinfection , Fish Diseases , Piscirickettsia , Piscirickettsiaceae Infections , Salmo salar , Animals , Piscirickettsia/physiology , Fish Diseases/microbiology , Fish Diseases/immunology , Piscirickettsiaceae Infections/veterinary , Piscirickettsiaceae Infections/microbiology , Coinfection/veterinary , Coinfection/microbiology , Coinfection/immunology , Chile , Sepsis/veterinary , Sepsis/microbiology , Sepsis/immunology
18.
J Parasitol ; 110(4): 351-359, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39106981

ABSTRACT

HALIOTREMA PTEROISI: Paperna, 1972 (Monogenoidea: Dactylogyridae) was found parasitizing the gill lamellae of devil firefish, Pterois miles (Bennet) (Perciformes: Scorpaenidae), in the Red Sea off Safaga (26°44'N, 33°56'E), Egypt. The parasite species was described based on morphological features of available specimens and transferred to PlatycephalotremaKritsky and Nitta, 2019 (Dactylogyridae) as Platycephalotrema pteroisi (Paperna, 1972) n. comb. The occurrence of Pl. pteroisi off Safaga, Egypt, represented a range extension for the helminth of about 160 km to the southwest of the southern end of the Gulf of Aqaba. The transfer of the species to Platycephalotrema based on an evaluation of morphological features was supported by an analysis of molecular sequences of the 28S rDNA gene of Pl. pteroisi and 49 other dactylogyrid species. Maximum-likelihood, Bayesian inference, and maximum parsimony analyses of this dactylogyrid sequence data revealed H. pteroisi to nest with significant support within the clade of Platycephalotrema spp. During the literature review of dactylogyrid species infecting scorpionfishes, it was determined that Ancyrocephalus sp. of Dyer et al. from luna lion fish Pterois lunulata Temminck and Schlegel collected off Okinawa-jima, Japan represented an undescribed species of Platycephalotrema.


Subject(s)
Fish Diseases , Gills , Perciformes , Phylogeny , Trematoda , Trematode Infections , Animals , Fish Diseases/parasitology , Fish Diseases/epidemiology , Trematode Infections/parasitology , Trematode Infections/veterinary , Perciformes/parasitology , Gills/parasitology , Indian Ocean , Trematoda/classification , Trematoda/anatomy & histology , Trematoda/genetics , Trematoda/isolation & purification , Egypt , DNA, Helminth/chemistry , Platyhelminths/classification , Platyhelminths/anatomy & histology , Platyhelminths/genetics , Platyhelminths/isolation & purification , DNA, Ribosomal/chemistry , RNA, Ribosomal, 28S/genetics , Prevalence , Bayes Theorem
19.
Front Immunol ; 15: 1452609, 2024.
Article in English | MEDLINE | ID: mdl-39091499

ABSTRACT

Galectins (Gals) are a type of S-type lectin that are widespread and evolutionarily conserved among metazoans, and can act as pattern recognition receptors (PRRs) to recognize pathogen-associated molecular patterns (PAMPs). In this study, 10 Gals (ToGals) were identified in the Golden pompano (Trachinotus ovatus), and their conserved domains, motifs, and collinearity relationships were analyzed. The expression of ToGals was regulated following infection to Cryptocaryon irritans and Streptococcus agalactiae, indicating that ToGals participate in immune responses against microbial pathogens. Further analysis was conducted on one important member, Galectin-3, subcellular localization showing that ToGal-3like protein is expressed both in the nucleus and cytoplasm. Recombinant protein obtained through prokaryotic expression showed that rToGal-3like can agglutinate red blood cells of rabbit, carp and golden pompano and also agglutinate and kill Staphylococcus aureus, Bacillus subtilis, Vibrio vulnificus, S. agalactiae, Pseudomonas aeruginosa, and Aeromonas hydrophila. This study lays the foundation for further research on the immune roles of Gals in teleosts.


Subject(s)
Galectins , Phylogeny , Animals , Galectins/genetics , Galectins/immunology , Galectins/metabolism , Fish Proteins/genetics , Fish Proteins/immunology , Fish Proteins/metabolism , Multigene Family , Streptococcus agalactiae/immunology , Fish Diseases/immunology , Fish Diseases/microbiology , Fishes/immunology , Fishes/genetics , Perciformes/immunology , Perciformes/genetics , Gene Expression Profiling
20.
Adv Parasitol ; 125: 105-157, 2024.
Article in English | MEDLINE | ID: mdl-39095111

ABSTRACT

Fish parasitology is a dynamic and internationally important discipline with numerous biological, ecological and practical applications. We reviewed optimal fish and parasite sampling methods for key ectoparasite phyla (i.e. Ciliophora, Platyhelminthes, Annelida and Arthropoda) as well as recent advances in molecular detection of ectoparasites in aquatic environments. Ideally, fish capture and anaesthesia as well as parasite recovery methods should be validated to eliminate potential sampling bias and inaccuracy in determining ectoparasite population parameters. There are considerable advantages to working with fresh samples and live parasites, when combined with appropriate fixation methods, as sampling using dead or decaying materials can lead to rapid decomposition of soft-bodied parasites and subsequent challenges for identification. Sampling methods differ between target phyla, and sometimes genera, with optimum techniques largely associated with identification of parasite microhabitat and the method of attachment. International advances in fish parasitology can be achieved through the accession of whole specimens and/or molecular voucher specimens (i.e. hologenophores) in curated collections for further study. This approach is now critical for data quality because of the increased application of environmental DNA (eDNA) for the detection and surveillance of parasites in aquatic environments where the whole organism may be unavailable. Optimal fish parasite sampling methods are emphasised to aid repeatability and reliability of parasitological studies that require accurate biodiversity and impact assessments, as well as precise surveillance and diagnostics.


Subject(s)
Ectoparasitic Infestations , Fish Diseases , Fishes , Animals , Fishes/parasitology , Ectoparasitic Infestations/parasitology , Ectoparasitic Infestations/veterinary , Ectoparasitic Infestations/diagnosis , Fish Diseases/parasitology , Fish Diseases/diagnosis , Specimen Handling/methods , Parasites/isolation & purification , Parasitology/methods
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