Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 990
Filtrar
1.
PLoS One ; 16(9): e0249156, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34534219

RESUMO

An infective prey has the potential to infect, kill and consume its predator. Such a prey-predator relationship fundamentally differs from the predator-prey interaction because the prey can directly profit from the predator as a growth resource. Here we present a population dynamics model of partial role reversal in the predator-prey interaction of two species, the bottom dwelling marine deposit feeder sea cucumber Apostichopus japonicus and an important food source for the sea cucumber but potentially infective bacterium Vibrio splendidus. We analyse the effects of different parameters, e.g. infectivity and grazing rate, on the population sizes. We show that relative population sizes of the sea cucumber and V. Splendidus may switch with increasing infectivity. We also show that in the partial role reversal interaction the infective prey may benefit from the presence of the predator such that the population size may exceed the value of the carrying capacity of the prey in the absence of the predator. We also analysed the conditions for species extinction. The extinction of the prey, V. splendidus, may occur when its growth rate is low, or in the absence of infectivity. The extinction of the predator, A. japonicus, may follow if either the infectivity of the prey is high or a moderately infective prey is abundant. We conclude that partial role reversal is an undervalued subject in predator-prey studies.


Assuntos
Comportamento Predatório/fisiologia , Stichopus/fisiologia , Vibrio , Animais , Ecossistema , Modelos Biológicos , Dinâmica Populacional , Stichopus/microbiologia , Vibrio/patogenicidade
2.
Mar Biotechnol (NY) ; 23(5): 766-776, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34480240

RESUMO

Epidermal mucus is an important barrier and regulating mediator in fish. MicroRNAs (miRNAs) are proved to be involved in various biological processes, also as promising biomarkers for disease diagnosis. Vibrio harveyi has long been a noticeable bacterial pathogen in Cynoglossus semilaevis aquaculture. To find the evidence whether there are indicating miRNAs in mucus and whether the miRNAs are related to infections caused by V. harveyi, miRNA profiles of mucus from V. harveyi infected fish and healthy controls were screened by small RNA sequencing and verified by quantitative real-time PCR. This is the first report about miRNA profiling of flatfish mucus, aiming at illustrating the pathogenesis of V. harveyi caused infection and developing disease-related biomarkers. The results revealed significant differences in expression levels of some miRNAs between infected fish and healthy ones. Three hundred differentially expressed miRNAs were obtained after filtering through FC > 2 or FC < 0.5 and most of the differential miRNAs were downregulated. After verification through qRT-PCR, four unique miRNAs, dre-miR-451, dre-miR-184, dre-miR-205-5p > ssa-miR-205b-5p, and dre-miR-181a-5p > ssa-miR-181a-5p, were identified as V. harveyi infection-related signatures, consistent with sequencing trend. The expression levels of these four miRNAs in the infected fish were all significantly lower than controls. These miRNAs in mucus could be used to differentiate diseased and healthy fish in a non-invasive way with practical value for large-scale disease screening. They also provided new insights into the mechanism underlying the bacterial infections in fish.


Assuntos
Doenças dos Peixes/microbiologia , Linguado/metabolismo , MicroRNAs/metabolismo , Vibrioses/metabolismo , Animais , Biomarcadores/metabolismo , MicroRNAs/genética , Muco/metabolismo , Vibrio/patogenicidade
3.
Sci Rep ; 11(1): 15831, 2021 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-34349168

RESUMO

Luminescent vibriosis is a major bacterial disease in shrimp hatcheries and causes up to 100% mortality in larval stages of penaeid shrimps. We investigated the virulence factors and genetic identity of 29 luminescent Vibrio isolates from Indian shrimp hatcheries and farms, which were earlier presumed as Vibrio harveyi. Haemolysin gene-based species-specific multiplex PCR and phylogenetic analysis of rpoD and toxR identified all the isolates as V. campbellii. The gene-specific PCR revealed the presence of virulence markers involved in quorum sensing (luxM, luxS, cqsA), motility (flaA, lafA), toxin (hly, chiA, serine protease, metalloprotease), and virulence regulators (toxR, luxR) in all the isolates. The deduced amino acid sequence analysis of virulence regulator ToxR suggested four variants, namely A123Q150 (AQ; 18.9%), P123Q150 (PQ; 54.1%), A123P150 (AP; 21.6%), and P123P150 (PP; 5.4% isolates) based on amino acid at 123rd (proline or alanine) and 150th (glutamine or proline) positions. A significantly higher level of the quorum-sensing signal, autoinducer-2 (AI-2, p = 2.2e-12), and significantly reduced protease activity (p = 1.6e-07) were recorded in AP variant, whereas an inverse trend was noticed in the Q150 variants AQ and PQ. The pathogenicity study in Penaeus (Litopenaeus) vannamei juveniles revealed that all the isolates of AQ were highly pathogenic with Cox proportional hazard ratio 15.1 to 32.4 compared to P150 variants; PP (5.4 to 6.3) or AP (7.3 to 14). The correlation matrix suggested that protease, a metalloprotease, was positively correlated with pathogenicity (p > 0.05) and negatively correlated (p < 0.05) with AI-2 and AI-1. The syntenic organization of toxS-toxR-htpG operon in V. campbellii was found to be similar to pathogenic V. cholerae suggesting a similar regulatory role. The present study emphasizes that V. campbellii is a predominant pathogen in Indian shrimp hatcheries, and ToxR plays a significant role as a virulence regulator in the quorum sensing-protease pathway. Further, the study suggests that the presence of glutamine at 150th position (Q150) in ToxR is crucial for the pathogenicity of V. campbellii.


Assuntos
Proteínas de Bactérias/metabolismo , Infecções por Bactérias Gram-Negativas/complicações , Luminescência , Penaeidae/microbiologia , Percepção de Quorum , Vibrio/patogenicidade , Fatores de Virulência/metabolismo , Sequência de Aminoácidos , Animais , Proteínas de Bactérias/genética , Infecções por Bactérias Gram-Negativas/microbiologia , Homologia de Sequência , Vibrio/genética , Vibrio/isolamento & purificação , Virulência , Fatores de Virulência/genética
4.
Mol Biol Rep ; 48(2): 1299-1310, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33590414

RESUMO

Antimicrobial compounds from the safest source have gained greater relevance because of their wide spectrum of possible applications, especially in aquaculture industry, where pathogenic threat and antibacterial resistance are serious concerns. Bacillus stercoris MBTDCMFRI Ba37 isolated from mangrove environment of tropical estuarine habitats of Cochin exhibited a wide spectrum of antibacterial activity against major aquaculture pathogens belonging to genus Vibrio and Aeromonas. The structural characterization of the antibacterial compound from this strain may help in identifying their role as a biocontrol agent in aquaculture and allied sectors. The highest antibacterial activity was detected in 3rd day culture, grown in a modified Bacillus medium containing 1% of glycerol and 0.5% of glutamic acid at 30 °C, pH 8.0 and 15 ppt saline conditions. The inhibitory activity of the cell free supernatant was evident even at 20% v/v dilution. Preliminary studies on the nature of antibacterial action indicated that the bioactive principle is stable at temperatures up to 70 °C, between pH 6-9 and instable to lyzozyme and proteolytic enzymes. Bioassay guided purification followed by spectroscopic characterization of active fractions of B. stercoris MBTDCMFRI Ba37 revealed that the compound 1-(1-Hydroxyethyl)-1,7,10,12,13,15,17 heptamethyl-16-oxatetracyclo[8.7.0.02,3.012,13]heptadecan-5-one, is responsible for its major antibacterial activity. This is the first report on isolation and characterization of an antibacterial compound from the species B. stercoris. The results of this study indicated that B. stercoris MBTDCMFRI Ba37 has beneficial antibacterial properties which could be useful in developing novel antimicrobial therapeutics against a variety of aquaculture and other pathogens.


Assuntos
Anti-Infecciosos/isolamento & purificação , Bacillus/química , Cetonas/isolamento & purificação , Vibrio/efeitos dos fármacos , Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Aquicultura , Meios de Cultura/química , Meios de Cultura/farmacologia , Ecossistema , Cetonas/química , Cetonas/farmacologia , Testes de Sensibilidade Microbiana , Probióticos/química , Probióticos/farmacologia , Vibrio/patogenicidade
5.
Mar Drugs ; 19(1)2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33401388

RESUMO

Although Psychrobacter strain M9-54-1 had been previously isolated from the microbiota of holothurians and shown to degrade quorum sensing (QS) signal molecules C6 and C10-homoserine lactone (HSL), little was known about the gene responsible for this activity. In this study, we determined the whole genome sequence of this strain and found that the full 16S rRNA sequence shares 99.78-99.66% identity with Psychrobacter pulmonis CECT 5989T and P. faecalis ISO-46T. M9-54-1, evaluated using the agar well diffusion assay method, showed high quorum quenching (QQ) activity against a wide range of synthetic N-acylhomoserine lactone (AHLs) at 4, 15, and 28 °C. High-performance liquid chromatography-mass-spectrometry (HPLC-MS) confirmed that QQ activity was due to an AHL-acylase. The gene encoding for QQ activity in strain M9-54-1 was identified from its genome sequence whose gene product was named AhaP. Purified AhaP degraded substituted and unsubstituted AHLs from C4- to C14-HSL. Furthermore, heterologous expression of ahaP in the opportunistic pathogen Pseudomonas aeruginosa PAO1 reduced the expression of the QS-controlled gene lecA, encoding for a cytotoxic galactophilic lectin and swarming motility protein. Strain M9-54-1 also reduced brine shrimp mortality caused by Vibrio coralliilyticus VibC-Oc-193, showing potential as a biocontrol agent in aquaculture.


Assuntos
Amidoidrolases/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Psychrobacter/química , Percepção de Quorum/efeitos dos fármacos , Vibrio/efeitos dos fármacos , Vibrio/patogenicidade , Virulência/efeitos dos fármacos , 4-Butirolactona/análogos & derivados , 4-Butirolactona/metabolismo , Acil-Butirolactonas/metabolismo , Animais , Artemia , Genoma Bacteriano/genética , Estrutura Molecular , Psychrobacter/genética , RNA Ribossômico 16S
6.
J Biol Chem ; 296: 100304, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33465375

RESUMO

Growing pieces of evidence show that the long noncoding RNAs (lncRNAs) as new regulators participate in the regulation of various physiological and pathological processes. The study of lncRNA in lower invertebrates is still unclear compared with that in mammals. Here, we identified a novel lncRNA, termed IRAK4-related lncRNA (IRL), as a key regulator for innate immunity in teleost fish. We find that miR-27c-3p inhibits IRAK4 expression and thus weakens the NF-κB-mediated signaling pathway. Furthermore, the Gram-negative bacterium Vibrio anguillarum and lipopolysaccharide significantly upregulated host lncRNA IRL expression. Results indicate that IRL functions as a competing endogenous RNA for miR-27c-3p to regulate protein abundance of IRAK4; thus, invading microorganisms are eliminated and immune responses are promoted. Our study also demonstrates the regulation mechanism that lncRNA IRL can competitively adsorb miRNA to regulate the miR-27c-3p/IRAK4 axis that is widespread in teleost fish.


Assuntos
Doenças dos Peixes/imunologia , Proteínas de Peixes/imunologia , Quinases Associadas a Receptores de Interleucina-1/imunologia , NF-kappa B/imunologia , Perciformes/imunologia , RNA Longo não Codificante/imunologia , Vibrioses/veterinária , Animais , Pareamento de Bases , Sequência de Bases , Mapeamento Cromossômico , Cromossomos/química , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/imunologia , Doenças dos Peixes/genética , Doenças dos Peixes/microbiologia , Proteínas de Peixes/genética , Regulação da Expressão Gênica , Imunidade Inata , Quinases Associadas a Receptores de Interleucina-1/genética , Intestinos/citologia , Intestinos/imunologia , Rim/citologia , Rim/imunologia , Lipopolissacarídeos/farmacologia , MicroRNAs/genética , MicroRNAs/imunologia , NF-kappa B/genética , Perciformes/genética , Perciformes/microbiologia , Cultura Primária de Células , RNA Longo não Codificante/genética , Transdução de Sinais , Vibrio/crescimento & desenvolvimento , Vibrio/patogenicidade , Vibrioses/genética , Vibrioses/imunologia , Vibrioses/microbiologia
7.
J Appl Microbiol ; 131(1): 485-498, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33187023

RESUMO

AIMS: Infection of seafood with pathogenic species of the genus Vibrio causes human food-borne illnesses. This study was executed to examine the antimicrobial resistance phenotypes, biofilm-forming capability and virulence-associated genes of Vibrio from fish and shellfishes. METHODS AND RESULTS: Three hundred fresh water and marine fish and shellfish samples were collected from wet markets and supermarkets in Mansoura, Egypt. Bacteriological examination and PCR amplification identified 92 Vibrio spp., including 42 Vibrio parahaemolyticus and 50 Vibrio alginolyticus isolates from the examined fish and shellfish (infection rate: 30·67%). However, V. vulnificus was not found in this study. Vibrio spp. exhibited variable frequencies of antimicrobial resistance with higher percentages to ampicillin and penicillin. Multidrug resistance (MDR) was detected in 69·04 and 38% of V. parahaemolyticus and V. alginolyticus respectively. PCR testing of virulence genes, tdh, trh and tlh revealed the presence of tlh and trh in 100 and 11·9% of V. parahaemolyticus isolates respectively and none of V. alginolyticus carried any of these genes. Biofilm-forming capability was displayed by 76% of V. parahaemolyticus and 73·8% of V. alginolyticus isolates. Both V. parahaemolyticus and V. alginolyticus showed nonsignificant weak positive correlations (r < 0·4) between antimicrobial pairs belonging to different classes; however, a significant positive correlation (P <0·05) between trh and resistance to erythromycin (r = 0·45) and imipenem (r = 0·38) was only identified in V. parahaemolyticus. CONCLUSIONS: This study reports the existence of MDR strains of V. parahaemolyticus and V. alginolyticus from the common types of fishes and shellfishes in Egypt. Furthermore, the presence of virulence genes in these isolates and the ability to produce a biofilm in vitro pose potential health hazards to consumers. SIGNIFICANCE AND IMPACT OF THE STUDY: Frequent monitoring of seafood for the presence of Vibrio spp. and their antimicrobial susceptibility, virulence determinants and biofilm-forming capability is important for assessing the risk posed by these organisms to the public and for improving food safety.


Assuntos
Peixes/microbiologia , Alimentos Marinhos/microbiologia , Frutos do Mar/microbiologia , Vibrio/efeitos dos fármacos , Vibrio/patogenicidade , Animais , Antibacterianos/farmacologia , Biofilmes/crescimento & desenvolvimento , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Egito , Inocuidade dos Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Prevalência , Vibrio/classificação , Vibrio/genética , Virulência/genética
8.
Can J Microbiol ; 67(3): 231-248, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32941745

RESUMO

Vibrio harveyi is one of the major pathogens in aquaculture. To identify the key virulence factors affecting pathogenesis of V. harveyi towards fish, we conducted a field investigation for three representative fish farms infected with V. harveyi. Multilocus sequence typing (MLST) and whole-genome sequencing were conducted to delineate the phylogenetic relationship and genetic divergence of V. harveyi. A total of 25 V. harveyi strains were isolated from the diseased fish and groundwater and were subtyped into 12 sequence types by MLST. Five virulence genes, mshB, pilA, hutR, ureB, and ureG, were variably presented in the sequenced strains. The virulence gene profiles strongly correlated with the distinct pathogenicity of V. harveyi strains, with a strain harboring all five genes exhibiting the highest virulence towards fish. Phenotype assay confirmed that reduced virulence correlated with decreased motility and biofilm formation ability. Additionally, three types of type VI secretion system, namely T6SS1, T6SS2, and T6SS3, were identified in V. harveyi strains, which can be classified into six, four, and 12 subtypes, respectively. In conclusion, the results indicated that the virulence level of V. harveyi is mainly determined by the above virulence genes, which may play vital roles in environmental adaptation for V. harveyi.


Assuntos
Genoma Bacteriano/genética , Vibrio/genética , Vibrio/patogenicidade , Fatores de Virulência/genética , Animais , Biofilmes/crescimento & desenvolvimento , Peixes/microbiologia , Variação Genética , Movimento , Tipagem de Sequências Multilocus , Filogenia , Sistemas de Secreção Tipo VI/genética , Vibrio/classificação , Sequenciamento Completo do Genoma
9.
J Appl Microbiol ; 130(2): 617-631, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32592599

RESUMO

AIMS: Extreme mortality events affecting Pinna nobilis, some associated to Vibrio mediterranei, have depleted many populations of this bivalve. The objective of this study was to demonstrate pathogenicity of V. mediterranei in the host P. nobilis by performing a bacterial challenge in P. nobilis to understand if V. mediterranei has specific virulence in this host. To assist this objective, a secondary objective was to develop a species-specific DNA diagnostic test. METHODS AND RESULTS: Pinna nobilis collected from local bays were used in a challenge experiment with V. mediterranei (strain IRTA18-108). The virulence in the host background of P. nobilis was demonstrated at doses of 103 CFUs per animal. An alignment of published Vibrio sp. atpA sequences was used to design V. mediterranei-specific primers. Furthermore, data mining of published literature and V. mediterranei genomes identified multiple virulence-related genes (vir genes) from which specific primers were designed for PCR detection of selected genes. CONCLUSION: Vibrio mediterranei strain IRTA18-108 is pathogenic in the host P. nobilis. The virulence genes sod, rtx and mshA were identified in this strain. Temperatures of 24°C or higher appear to trigger onset of virulence. Sensitivity and specificity of the Vm atpA PCR is useful for diagnosis of Vibriosis in shellfish. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of previously described virulence genes have been confirmed in this strain. The specific Vm atpA PCR assay will aid management of future epizootics of this emerging pathogen of aquatic fauna, and improve surveillance capabilities for mortality events where Vibrios are suspect.


Assuntos
Bivalves/microbiologia , Microbiologia de Alimentos/métodos , Frutos do Mar/microbiologia , Vibrio/isolamento & purificação , Vibrio/patogenicidade , Animais , Proteínas de Bactérias/genética , Reação em Cadeia da Polimerase , Especificidade da Espécie , Vibrio/genética , Virulência/genética
10.
Braz J Microbiol ; 52(1): 335-347, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33237498

RESUMO

Antimicrobial compounds from the natural source have gained greater relevance because of their wide spectrum of possible applications, especially in the aquaculture industry where pathogenic threat and antibacterial resistance are serious concerns. In this regard, Pseudomonas aeruginosa MBTDCMFRI Ps04 (P. aeruginosa Ps04) strain isolated from the tropical estuarine habitats of Cochin was evaluated for its antibacterial potential against major aquaculture pathogens. The physiological conditions for the maximum production of the active metabolite were also optimized. An activity-guided approach was employed further to isolate and characterize the secondary metabolite responsible for the inhibitory potential. It was found that the cell free supernatant (CFS) of P. aeruginosa Ps04 exhibited strong antibacterial activity against major aquaculture pathogens belonging to the genus Vibrio and Aeromonas and retained its potential even at 30% (v/v) dilution. The highest antibacterial activity was detected from 3rd day culture, grown in glycerol alanine media (1% each) as carbon and nitrogen source, respectively, at 30 °C, pH 7.0 and at a salinity of 20 parts per thousand (ppt). The activity of the antagonistic principle was found to be stable against variations in pH (pH 2-pH 12), temperature (up to 120 °C) and enzymatic treatments. Bioassay-guided purification followed by spectroscopic characterization of active fractions of P. aeruginosa Ps04 revealed that the compound 4-Hydroxy-11-methylpentacyclo [11.8.0.02,3.011, 12.016,17]henicosa-1,3,5,8(9),17-penten-14-one is responsible for its major antibacterial activity. The results of this study indicated that P. aeruginosa Ps04 has beneficial antibacterial properties which could be used in developing novel antimicrobial therapeutics against a variety of aquaculture pathogens.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Meios de Cultura/farmacologia , Cetonas/isolamento & purificação , Cetonas/farmacologia , Pseudomonas aeruginosa/química , Pseudomonas aeruginosa/metabolismo , Aeromonas/efeitos dos fármacos , Aeromonas/patogenicidade , Antibacterianos/química , Antibacterianos/isolamento & purificação , Aquicultura/métodos , Bactérias/classificação , Bactérias/patogenicidade , Estuários , Cetonas/química , Testes de Sensibilidade Microbiana , RNA Ribossômico 16S/genética , Metabolismo Secundário , Clima Tropical , Vibrio/efeitos dos fármacos , Vibrio/patogenicidade
11.
J Invertebr Pathol ; 178: 107517, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33333063

RESUMO

The occurrence of infectious diseases poses a significant threat to the aquaculture industry worldwide. Therefore, characterization of potentially harmful pathogens is one of the most important strategies to control disease outbreaks. In the present study, we investigated for the first time the pathogenicity of two Vibrio species, Vibrio metschnikovii, a foodborne pathogen that causes fatalities in humans, and Vibrio areninigrae, a bacteria isolated from black sand in Korea, using a crustacean model, the signal crayfish Pacifastacus leniusculus. Mortality challenges indicated that injection of V. metschnikovii (108 CFU/crayfish) has a mortality percentage of 22% in crayfish. In contrast, injection of P. leniusculus with 108 or 107 CFU of V. areninigrae resulted in 100% mortality within one and two days post-injection, respectively. V. areninigrae was successfully re-isolated from hepatopancreas of infected crayfish and caused 100% mortality when reinjected into new healthy crayfish. As a consequence of this infection, histopathological analysis revealed nodule formation in crayfish hepatopancreas, heart, and gills, as well as sloughed cells inside hepatopancreatic tubules and atrophy. Moreover, extracellular crude products (ECP's) were obtained from V. areninigrae in order to investigate putative virulence factors. In vivo challenges with ECP's caused >90% mortalities within the first 24 h. In vitro challenges with ECP's of hemocytes induced cytotoxicity of hemocytes within the first hour of exposure. These findings represent the first report that V. areninigrae is a highly pathogenic bacterium that can cause disease in crustaceans. On the contrary, V. metschnikovii could not represent a threat for freshwater crayfish.


Assuntos
Astacoidea/microbiologia , Vibrio , Animais , Citotoxinas/farmacologia , Brânquias/microbiologia , Brânquias/patologia , Hemócitos/efeitos dos fármacos , Hepatopâncreas/microbiologia , Hepatopâncreas/patologia , Mortalidade , República da Coreia , Alimentos Marinhos/microbiologia , Vibrio/isolamento & purificação , Vibrio/patogenicidade , Vibrioses/transmissão
12.
J Fish Dis ; 44(1): 89-105, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32971569

RESUMO

Tropical shrimp, like Litopenaeus vannamei, in land-based recirculating aquaculture systems (RAS) are often kept at low water salinities to reduce costs for artificial sea salt and the amount of salty wastewater. Although these shrimp are tolerant against low salinities, innate immunity suppression and changes in the microbial composition in the water can occur. As especially Vibrio spp. are relevant for shrimp health, alterations in the species composition of the Vibrio community were analysed in water from six RAS, run at 15‰ or 30‰. Additionally, pathogenicity factors including pirA/B, VPI, toxR, toxS, vhh, vfh, tdh, trh, flagellin genes and T6SS1/2 of V. parahaemolyticus were analysed. The Vibrio composition differed significantly depending on water salinity. In RAS at 15‰, higher numbers of the potentially pathogenic species V. parahaemolyticus, V. owensii and V. campbellii were detected, and especially in V. parahaemolyticus, various pathogenicity factors were present. A reduced salinity may therefore pose a higher risk of disease outbreaks in shrimp RAS. Because some of the detected pathogenicity factors are relevant for human health, this might also affect food safety. In order to produce healthy shrimp as a safe food for human consumption, maintaining high water salinities seems to be recommendable.


Assuntos
Aquicultura , Penaeidae/microbiologia , Salinidade , Água do Mar/microbiologia , Vibrio/classificação , Animais , Carga Bacteriana , Inocuidade dos Alimentos , Genes Bacterianos , Alimentos Marinhos/microbiologia , Água do Mar/química , Vibrio/patogenicidade , Vibrioses/veterinária , Fatores de Virulência/genética
13.
Front Immunol ; 11: 607754, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33324424

RESUMO

Vibrio harveyi causes vibriosis in nearly 70% of grouper (Epinephelus sp.), seriously limiting grouper culture. As well as directly inhibiting pathogens, the gut microbiota plays critical roles in immune homeostasis and provides essential health benefits to its host. However, there is still little information about the variations in the immune response to V. harveyi infection and the gut microbiota of grouper. To understand the virulence mechanism of V. harveyi in the pearl gentian grouper, we investigated the variations in the pathological changes, immune responses, and gut bacterial communities of pearl gentian grouper after exposure to differently virulent V. harveyi strains. Obvious histopathological changes were detected in heart, kidney, and liver. In particular, nodules appeared and huge numbers of V. harveyi cells colonized the liver at 12 h postinfection (hpi) with highly virulent V. harveyi. Although no V. harveyi was detected in the gut, the infection simultaneously induced a gut-liver immune response. In particular, the expression of 8 genes associated with cellular immune processes, including genes encoding inflammatory cytokines and receptors, and pattern recognition proteins, was markedly induced by V. harveyi infection, especially with the highly virulent V. harveyi strain. V. harveyi infection also induced significant changes in gut bacterial community, in which Vibrio and Photobacterium increased but Bradyrhizobium, Lactobacillus, Blautia, and Faecalibaculum decreased in the group infected with the highly virulent strain, with accounting for 82.01% dissimilarity. Correspondingly, four bacterial functions related to bacterial pathogenesis were increased by infection with highly virulent V. harveyi, whereas functions involving metabolism and genetic information processing were reduced. These findings indicate that V. harveyi colonizes the liver and induces a gut-liver immune response that substantially disrupts the composition of and interspecies interactions in the bacterial community in fish gut, thereby altering the gut-microbiota-mediated functions and inducing fish death.


Assuntos
Doenças dos Peixes/microbiologia , Peixes/microbiologia , Microbioma Gastrointestinal , Trato Gastrointestinal/microbiologia , Fígado/microbiologia , Vibrioses/veterinária , Vibrio/patogenicidade , Animais , Disbiose , Feminino , Doenças dos Peixes/genética , Doenças dos Peixes/imunologia , Doenças dos Peixes/metabolismo , Peixes/genética , Peixes/imunologia , Peixes/metabolismo , Trato Gastrointestinal/imunologia , Trato Gastrointestinal/metabolismo , Regulação Bacteriana da Expressão Gênica , Interações Hospedeiro-Patógeno , Fígado/imunologia , Fígado/metabolismo , Masculino , Vibrio/genética , Vibrio/imunologia , Vibrioses/imunologia , Vibrioses/metabolismo , Vibrioses/microbiologia , Virulência
14.
BMC Microbiol ; 20(1): 341, 2020 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-33176689

RESUMO

BACKGROUND: Vibrio scophthalmi is an opportunistic bacterial pathogen, which is widely distributed in the marine environment. Earlier studies have suggested that it is a normal microorganism in the turbot gut. However, recent studies have confirmed that this bacterial strain can cause diseases in many different marine animals. Therefore, it is necessary to investigate its whole genome for better understanding its physiological and pathogenic mechanisms. RESULTS: In the present study, we obtained a pathogenic strain of V. scophthalmi from diseased half-smooth tongue sole (Cynoglossus semilaevis) and sequenced its whole genome. Its genome contained two circular chromosomes and two plasmids with a total size of 3,541,838 bp, which harbored 3185 coding genes. Among these genes, 2648, 2298, and 1915 genes could be found through annotation information in COG, Blast2GO, and KEGG databases, respectively. Moreover, 10 genomic islands were predicted to exist in the chromosome I through IslandViewer online system. Comparison analysis in VFDB and PHI databases showed that this strain had 334 potential virulence-related genes and 518 pathogen-host interaction-related genes. Although it contained genes related to four secretion systems of T1SS, T2SS, T4SS, and T6SS, there was only one complete T2SS secretion system. Based on CARD database blast results, 180 drug resistance genes belonging to 27 antibiotic resistance categories were found in the whole genome of such strain. However, there were many differences between the phenotype and genotype of drug resistance. CONCLUSIONS: Based on the whole genome analysis, the pathogenic V. scophthalmi strain contained many types of genes related to pathogenicity and drug resistance. Moreover, it showed inconsistency between phenotype and genotype on drug resistance. These results suggested that the physiological mechanism seemed to be complex.


Assuntos
Doenças dos Peixes/microbiologia , Linguados/microbiologia , Vibrioses/veterinária , Vibrio/genética , Animais , Antibacterianos/farmacologia , Farmacorresistência Bacteriana/genética , Doenças dos Peixes/patologia , Genes Bacterianos/genética , Tamanho do Genoma , Genoma Bacteriano/genética , Ilhas Genômicas , Interações Hospedeiro-Patógeno/genética , Testes de Sensibilidade Microbiana , Filogenia , Vibrio/classificação , Vibrio/efeitos dos fármacos , Vibrio/patogenicidade , Vibrioses/microbiologia , Vibrioses/patologia , Fatores de Virulência/genética
16.
Proc Natl Acad Sci U S A ; 117(45): 28374-28383, 2020 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-33097672

RESUMO

Viruses, such as white spot syndrome virus, and bacteria, such as Vibrio species, wreak havoc in shrimp aquaculture [C. M. Escobedo-Bonilla et al., J. Fish. Dis. 31, 1-18 (2008)]. As the main portal of entry for shrimp-related pathogens remain unclear, infectious diseases are difficult to prevent and control. Because the cuticle is a strong pathogen barrier, regions lacking cuticular lining, such as the shrimp's excretory organ, "the antennal gland," are major candidate entry portals [M. Corteel et al., Vet. Microbiol. 137, 209-216 (2009)]. The antennal gland, up until now morphologically underexplored, is studied using several imaging techniques. Using histology-based three-dimensional technology, we demonstrate that the antennal gland resembles a kidney, connected to a urinary bladder with a nephropore (exit opening) and a complex of diverticula, spread throughout the cephalothorax. Micromagnetic resonance imaging of live shrimp not only confirms the histology-based model, but also indicates that the filling of the diverticula is linked to the molting cycle and possibly involved therein. Based on function and complexity, we propose to rename the antennal gland as the "nephrocomplex." By an intrabladder inoculation, we showed high susceptibility of this nephrocomplex to both white spot syndrome virus and Vibrio infection compared to peroral inoculation. An induced drop in salinity allowed the virus to enter the nephrocomplex in a natural way and caused a general infection followed by death; fluorescent beads were used to demonstrate that particles may indeed enter through the nephropore. These findings pave the way for oriented disease control in shrimp.


Assuntos
Muda/fisiologia , Penaeidae/microbiologia , Penaeidae/virologia , Glândulas Sebáceas/microbiologia , Glândulas Sebáceas/patologia , Animais , Aquicultura , Salinidade , Glândulas Sebáceas/diagnóstico por imagem , Glândulas Sebáceas/virologia , Vibrio/patogenicidade , Vibrioses/patologia , Vibrioses/veterinária , Internalização do Vírus , Vírus da Síndrome da Mancha Branca 1/patogenicidade
17.
Sci Rep ; 10(1): 14329, 2020 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-32868874

RESUMO

Here, 70 potential Vibrio pathogens belonging to nine species, dominated by Vibrio harveyi, were isolated and identified from diseased aquacultured marine fish in South China. Subsequently, the prevalence of 11 virulence genes and the resistance to 15 antibiotics in these strains were determined. Most strains possessed atypical virulence genes in addition to typical virulence genes. Notably, hflk and chiA originating from V. harveyi, and flaC associated with V. anguillarum were detected in more than 40% of atypical host strains. Multidrug resistance was widespread: 64.29% strains were resistant to more than three antibiotics, and the multi-antibiotic resistance index ranged from 0.00 to 0.60. The proportions of strains resistant to the antibiotics vancomycin, amoxicillin, midecamycin, and furazolidone all exceeded 50%; nevertheless, all strains were sensitive to florfenicol, norfloxacin, and ciprofloxacin. Furthermore, both virulence genes and antibiotic resistance were more prevalent in Hainan than in Guangdong, owing to the warmer climate and longer annual farming time in Hainan. These results therefore suggest that warming temperatures and overuse of antibiotics are probably enhancing antibiotic resistance and bacterial infection. This study reveals that pathogenic Vibrio spp. with multi-antibiotic resistance are highly prevalent among marine fish in South China and thus warrant further attention. The results will provide helpful guidance for ecological regulation and local antibiotic use in the control of marine fish farming' Vibrio diseases in South China, facilitating the implementation of national green and healthful aquaculture.


Assuntos
Aquicultura , Farmacorresistência Bacteriana Múltipla/genética , Doenças dos Peixes/microbiologia , Peixes/microbiologia , Vibrio/genética , Fatores de Virulência/genética , Animais , China , Interações Hospedeiro-Parasita/genética , Vibrio/isolamento & purificação , Vibrio/patogenicidade
18.
BMC Genomics ; 21(1): 599, 2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32867668

RESUMO

BACKGROUND: Vibriosis has been implicated in major losses of larvae at shellfish hatcheries. However, the species of Vibrio responsible for disease in aquaculture settings and their associated virulence genes are often variable or undefined. Knowledge of the specific nature of these factors is essential to developing a better understanding of the environmental and biological conditions that lead to larvae mortality events in hatcheries. We tested the virulence of 51 Vibrio strains towards Pacific Oyster (Crassostreae gigas) larvae and sequenced draft genomes of 42 hatchery-associated vibrios to determine groups of orthologous genes associated with virulence and to determine the phylogenetic relationships among pathogens and non-pathogens of C. gigas larvae. RESULTS: V. coralliilyticus strains were the most prevalent pathogenic isolates. A phylogenetic logistic regression model identified over 500 protein-coding genes correlated with pathogenicity. Many of these genes had straightforward links to disease mechanisms, including predicted hemolysins, proteases, and multiple Type 3 Secretion System genes, while others appear to have possible indirect roles in pathogenesis and may be more important for general survival in the host environment. Multiple metabolism and nutrient acquisition genes were also identified to correlate with pathogenicity, highlighting specific features that may enable pathogen survival within C. gigas larvae. CONCLUSIONS: These findings have important implications on the range of pathogenic Vibrio spp. found in oyster-rearing environments and the genetic determinants of virulence in these populations.


Assuntos
Crassostrea/virologia , Genes Virais , Vibrio/genética , Animais , Filogenia , Vibrio/classificação , Vibrio/patogenicidade , Virulência/genética
19.
J Bacteriol ; 202(24)2020 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-32778562

RESUMO

Vibrio is a large and diverse genus of bacteria, of which most are nonpathogenic species found in the aquatic environment. However, a subset of the Vibrio genus includes several species that are highly pathogenic, either to humans or to aquatic animals. In recent years, Danio rerio, commonly known as the zebrafish, has emerged as a major animal model used for studying nearly every aspect of biology, including infectious diseases. Zebrafish are especially useful because the embryos are transparent, larvae are small and facilitate imaging studies, and numerous transgenic fish strains have been constructed. Zebrafish models for several pathogenic Vibrio species have been described, and indeed a fish model is highly relevant for the study of aquatic bacterial pathogens. Here, we summarize the zebrafish models that have been used to study pathogenic Vibrio species to date.


Assuntos
Modelos Animais de Doenças , Vibrioses/microbiologia , Vibrio/fisiologia , Peixe-Zebra , Animais , Humanos , Vibrio/classificação , Vibrio/genética , Vibrio/patogenicidade , Virulência , Peixe-Zebra/microbiologia
20.
Fish Shellfish Immunol ; 106: 555-562, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32768706

RESUMO

Salinity is an important environmental factor which usually goes unnoticed in shrimp growout systems. In the present study an attempt was done to analyse the physiological and immunological responses of Penaeus monodon to Vibrio harveyi infection under acute salinity stress. Shrimps were challenged with V. harveyi under 5‰ salinity stress, 35‰ salinity stress and optimal salinity (15‰) conditions by intramuscular injection. A control was maintained without bacterial challenge. Haemolymph was collected from shrimps soon after salinity change before V. harveyi challenge (post salinity change day (PSD) 0), on post challenge day (PCD) 2, 7 and 10. Immune variables viz., total haemocyte count (THC), phenol oxidase activity (PO), Nitroblue tetrazolium salt (NBT) reduction, alkaline phosphatase activity (ALP), acid phosphatase activity (ACP) and metabolic variables viz., total protein (TP), total carbohydrates (TC), total free amino acids (TFAA), total lipids (TL), glucose (Gl) and cholesterol (Ch) were then determined. One way ANOVA followed by Duncan's multiple comparison of the means revealed significant differences between shrimps subjected to different salinity conditions and then challenged with V. harveyi (P < 0.05). Post challenge survival was significantly higher in shrimps maintained at 15‰ and acute salinity stress reduced the survival rate. However, pathogenicity of V. harveyi was slightly higher at 35‰ than at 5‰. At the onset of salinity stress, parameters viz., THC, NBT and ACP significantly reduced and TC increased at 5‰ and 35‰. Following V. harveyi challenge, an overall increase could be observed in metabolic variables on PCD2 and immune variables on PCD2 and 7 in P. monodon maintained at 15‰ compared to the control. Even though an increase in immune response and metabolic variables could be obtained on post challenge days in shrimps under salinity stress compared to the control, it was considerably low in comparison with shrimps maintained at 15‰. Regression analysis proved that NBT, ALP, TP and TL could be proposed as potential stress indicators to evaluate shrimp health status. In brief, it may be concluded from the study that acute salinity changes evoke physiological responses that affect the immunocompetence and metabolic performance of P. monodon against V. harveyi challenge, thereby increasing the susceptibility to infection. Moreover higher salinity enhanced the pathogenicity of V. harveyi.


Assuntos
Imunocompetência , Penaeidae/imunologia , Salinidade , Estresse Salino/imunologia , Vibrio/patogenicidade , Animais , Virulência
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...