RESUMEN

The complement system is pivotal in innate immune defense, with Complement 1qb (C1qb) playing a key role in recognizing immune complexes and initiating the classical pathway. In this research, we cloned the full-length cDNA of silver pomfret (Pampus argenteus) c1qb and demonstrated its role in mediating defense responses against Nocardia seriolae (N. seriolae) infection, which notably causes significant economic losses in the aquaculture industry. Our investigation revealed that N. seriolae infection led to tissue damage in fish bodies, as observed in tissue sections. Subsequent analysis of differential genes (DEGs) in the transcriptome highlighted genes linked to apoptosis and inflammation. Through experiments involving overexpression and interference of c1qb in vitro, we confirmed that c1qb could suppress N. seriolae-induced apoptosis and inflammation. Moreover, overexpression of c1qb hindered N. seriolae invasion, and the purified and replicated C1qb protein displayed antimicrobial properties. Additionally, our study unveiled that overexpression of c1qb might stimulate the expression of membrane attack complexes (MAC), potentially enhancing opsonization and antibacterial effects. In conclusion, our findings offer valuable insights into the immune antibacterial mechanisms of c1qb and contribute to the development of strategies for controlling N. seriolae.

Asunto(s)

Apoptosis , Complemento C1q , Complejo de Ataque a Membrana del Sistema Complemento , Inflamación , Nocardia , Complemento C1q/metabolismo , Complemento C1q/genética , Apoptosis/genética , Animales , Complejo de Ataque a Membrana del Sistema Complemento/metabolismo , Inflamación/genética , Inflamación/metabolismo , Enfermedades de los Peces/inmunología , Enfermedades de los Peces/microbiología , Nocardiosis/inmunología , Nocardiosis/microbiología , Nocardiosis/metabolismo , Nocardiosis/genética

RESUMEN

IL-8 and IL-10 are crucial inflammatory cytokines that participate in defending host cells against infections. To demonstrate the function of the two interleukin genes in largemouth bass (Micropterus salmoides), we initially cloned and identified the cDNA sequences of il-8 and il-10 in largemouth bass, referred to as Msil-8 and Msil-10, respectively. The open reading frame (ORF) of Msil-8 was 324 bp in length, encoding 107 amino acids, while the ORF of Msil-10 consisted of 726 bp and encoded 241 amino acids. Furthermore, the functional domains of the SCY domain in MsIL-8 and the IL-10 family signature motif in MsIL-10 were highly conserved across vertebrates. Additionally, both MsIL-8 and MsIL-10 showed close relationships with M. dolomieu. Constitutive expression of Msil-8 and Msil-10 was observed in various tissues, with the highest level found in the head kidney. Subsequently, largemouth bass were infected with Nocardia seriolae via intraperitoneal injection to gain a further understanding of the function of these two genes. Bacterial loads were initially detected in the foregut, followed by the midgut, hindgut, and liver. The mRNA expression of Msil-8 was significantly down-regulated after infection, especially at 2 days post-infection (DPI), with a similar expression to Msil-10. In contrast, the expression of Msil-8 and Msil-10 was significantly upregulated in the foregut at 14 DPI. Taken together, these results reveal that the function of IL-8 and IL-10 was likely hindered by N. seriolae, which promoted bacterial proliferation and intercellular diffusion.

Asunto(s)

Lubina , Nocardiosis , Nocardia , Animales , Lubina/genética , Interleucina-8/genética , Interleucina-10/genética , Nocardiosis/genética , Nocardiosis/veterinaria , Aminoácidos

RESUMEN

Non-coding RNAs (ncRNAs) play vital roles in regulating the expression levels of genes that control essential biological functions, including immune response to bacterial infections in teleost. To dissect the roles of ncRNAs in the Channa argus (snakehead), a systematic analysis of the expression profiles of circRNA, miRNA and mRNA, as well as competing endogenous RNAs (ceRNA) regulatory networks in the kidney of snakehead following Nocardia seriolae infection were performed in the present study. A total of 111 differentially expressed circRNAs, 706 differentially expressed miRNAs, and 2548 differentially expressed mRNAs were identified in the N. seriolae infected snakehead. Based on these differently expressed RNAs, we identified 55 circRNA-mRNA pairs, 124 miRNA-mRNA pairs, and 35 circRNA-miRNA-mRNA regulatory networks, including dre-miR-103-CD302, dre-miR-27e-IGSF3, novel_circ_0005462/novel_403-IGKC, novel_circ_0001750/novel_circ_0002162-novel_477-OCLN, and novel_circ_0003847-novel_4-KCNAB3. In addition, luciferase reporter assay was employed to detect the target relationships of several circRNA-miRNA-mRNA pairs. Taken together, this study demonstrates that the genes associated with immunity and structures in the kidney of snakehead can be regulated by circRNAs and miRNAs at post-transcription levels, and provided theoretical guidance for ncRNAs studies for other teleost. However, further studies are still in great need to validate the regulatory mechanisms of ncRNAs in snakehead.

Asunto(s)

MicroARNs , Nocardiosis , Animales , MicroARNs/genética , MicroARNs/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , ARN Circular/genética , Nocardiosis/genética , Riñón/metabolismo

RESUMEN

Nocardia seriolae is the main pathogen of fish nocardiosis. In our previous study, alanine dehydrogenase was identified as a potential virulence factor of N. seriolae. On the basis of this fact, the alanine dehydrogenase gene of N. seriolae (NsAld) was knocked out to establish the strain ΔNsAld for vaccine development against fish nocardiosis in this study. The LD50 of strain ΔNsAld was 3.90 × 105 CFU/fish, higher than that of wild strain (5.28 × 104 CFU/fish) significantly (p < 0.05). When the strain ΔNsAld was used as a live vaccine to immunize hybrid snakehead (Channa maculata ♀ × Channa argus ♂) at 2.47 × 105 CFU/fish by intraperitoneal injection, the non-specific immune indexes (LZM, CAT, AKP, ACP and SOD activities), specific antibody (IgM) titers and several immune-related genes (CD4, CD8α, IL-1ß, MHCIα, MHCIIα and TNFα) were up-regulated in different tissues, indicating that this vaccine could induce humoral and cell-mediated immune responses. Furthermore, the relative percentage survival (RPS) of ΔNsAld vaccine was calculated as 76.48% after wild N. seriolae challenge. All these results suggest that the strain ΔNsAld could be a potential candidate for live vaccine development to control fish nocardiosis in aquaculture.

Asunto(s)

Enfermedades de los Peces , Nocardiosis , Animales , Alanina-Deshidrogenasa/genética , Eliminación de Gen , Nocardiosis/prevención & control , Nocardiosis/veterinaria , Nocardiosis/genética , Peces/genética , Desarrollo de Vacunas

RESUMEN

Mycetoma is a neglected tropical disease (NTD) declared by the World Health Organization (WHO) in 2016. It is characterized by the progressive growth of nodules and granulomatous lesions on the legs, arms, and trunk. It is potentially disfiguring and causes disability or amputations in working-age people from marginalized areas. The causative agents can be fungi (eumycetoma) or actinobacteria (actinomycetoma), the latter being the most common in America and Asia. Nocardia brasiliensis is the most important causal agent of actinomycetoma in the Americas. Taxonomic problems have been reported when identifying this species, so this study aimed to detect the 16S rRNA gene variations in N. brasiliensis strains using an in silico enzymatic restriction technique. The study included strains from clinical cases of actinomycetoma in Mexico, isolated from humans and previously identified as N. brasiliensis by traditional methods. The strains were characterized microscopically and macroscopically, then subjected to DNA extraction and amplification of the 16S rRNA gene by PCR. The amplification products were sequenced, and consensus sequences were constructed and used for genetic identification and in silico restriction enzyme analysis with the New England BioLabs® NEBcutter program. All study strains were molecularly identified as N. brasiliensis; however, in silico restriction analysis detected a diversity in the restriction patterns that were finally grouped and subclassified into 7 ribotypes. This finding confirms the existence of subgroups within N. brasiliensis. The results support the need to consider N. brasiliensis as a complex species.

Asunto(s)

Micetoma , Nocardiosis , Nocardia , Humanos , Micetoma/diagnóstico , Micetoma/genética , Micetoma/microbiología , ARN Ribosómico 16S/genética , América Latina , Genes de ARNr , Nocardia/genética , Región del Caribe , Nocardiosis/genética , Nocardiosis/microbiología

RESUMEN

Evidence has been demonstrated that lncRNAs are involved in a variety of immune responses in vertebrate. It has been demonstrated that immune-related lncRNAs play vital functions in immune regulation against infections in teleost. Nocardia seriolae, as one of the Gram-positive bacteria, can cause chronic systemic granulomatous disease for snakehead (Channa argus). However, how lncRNAs function in the immune regulation process once snakehead was infected with N. seriolae infection has not been studied so far. Accordingly, transcription landscapes of lncRNAs and mRNAs in snakehead were investigated. A total of 1,991 lncRNA were obtained. Totally, we predicted 57,584 co-expression and 16,047 co-location lncRNA-mRNA pairs. To further analyze the potential function of these lncRNAs, GO enrichment analysis and KEGG signal pathways were performed on the target mRNAs of these differently expressed lncRNAs, suggesting that lncRNAs may play essential roles in modulating mRNA expression levels, and subsequently trigger downstream immune signaling pathways to regulate the immune response in snakehead. In addition, 9 DEmRNA and 3 lncRNAs were randomly selected for qRT-PCR analyzed, which confirmed the accuracy of transcriptome data. These results can provide novel knowledge about lncRNAs in immune responses process in snakehead, and can serve as important resources for further investigating the roles of lncRNAs during pathogen infections in teleost.

Asunto(s)

Nocardiosis , ARN Largo no Codificante , Animales , ARN Mensajero/genética , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Transcriptoma , Nocardiosis/genética , Nocardiosis/veterinaria , Perfilación de la Expresión Génica/veterinaria

RESUMEN

Nocardia seriolae, a Gram-positive facultative intercellular pathogen, has been identified as the causative agent of fish nocardiosis, causing substantial mortality and morbidity of a wide range of fish species. Looking into that fact, the effective vaccine against this pathogen is urgently needed to control the significant losses in aquaculture practices. In order to induct attenuated strains for developing the potential live vaccines, the mutagenic N. seriolae strain S-250 and U-20 were obtained from wild-type strain ZJ0503 through continuous passaging and ultraviolet (UV) irradiation, respectively. Additionally, the biological characteristic, virulence, stability, mediating immune response and supplying protective efficacy to hybrid snakehead of the S-250 and U-20 strains were determined in the present study. The results showed that U-20 strain displayed dramatic changes in morphological characteristic and significant decreased in the virulence to hybrid snakehead, while that of S-250 strain had no obvious different in comparison to ZJ0503 strain. When hybrid snakehead were intraperitoneally injected with ZJ0503, S-250 and U-20 strains at their respective sub-clinical dosage, the non-specific immunity parameters (serum LYZ, POD, ACP, AKP and SOD activities), specific antibody (IgM) titers production and immune-related genes (CC1, CC2, IL-1ß, IL-8, TNFα, IFNγ, MHCIα, MHCIIα, CD4, CD8α, TCRα and TCRß) expression were up-regulated, indicating that they were able to trigger humoral and cell-mediated immune responses. Furthermore, the protective efficacy in hybrid snakehead after vaccination with ZJ0503, S-250 and U-20 strains, in terms of relative percentage survival (RPS), were 28.85%, 56.89% and 89.65% respectively. Taken together, two attenuated N. seriolae strains S-250 and U-20 were obtained successfully and they could elicit strong immune response and supply protective efficacy to hybrid snakehead against N. seriolae, which suggested that these two attenuated strains were the potential candidates for live vaccine development to control fish nocardiosis in aquaculture.

Asunto(s)

Enfermedades de los Peces , Nocardiosis , Nocardia , Animales , Nocardiosis/prevención & control , Nocardiosis/veterinaria , Nocardiosis/genética , Peces , Vacunas Atenuadas

RESUMEN

Northern snakehead (Channa argus) is an indigenous fish species and is one of popularly cultured snakeheads in China and other Asian countries. Unfortunately, Nocardia seriolae infections have caused considerable losses in the snakehead aquaculture industry. However, the infectivity and the immune response induced by N. seriolae in snakehead are unclear. In order to better understand the immune response of Northern snakehead in a series of time points after N. seriolae challenge, we conducted the transcriptomic comparison in snakehead spleen at 48, 96, and 144 h after the challenge of N. seriola against their control counterparts. Gene annotation and pathway analysis of differentially expressed genes (DEGs) were carried out to understand the functions of the DEGs. Additionally, protein-protein interaction networks were conducted to obtain the interaction relationships of immune-related DEGs. These results revealed the expression changes of multiple DEGs and signaling pathways involved in immunity during N. seriolae infection, which will facilitate our comprehensive understanding of the mechanisms involved in the immune response to bacterial infection in the northern snakehead.

Asunto(s)

Nocardiosis , Nocardia , Animales , Bazo , Nocardia/genética , Nocardiosis/genética , Nocardiosis/microbiología , Perfilación de la Expresión Génica

RESUMEN

The genus Nocardia includes ubiquitous environmental saprophytes and the most frequently isolated aerobic actinomycete human pathogen responsible for localized or disseminated infection. Herein, the species distribution and antimicrobial susceptibility profiles of 441 nonrepetitive Nocardia strains are reported, collected from 21 provinces/cities in China over 13 years (from 2009 to 2021). These isolates were identified to species level by mass spectrometry or targeted DNA sequencing. The susceptibility profiles of Nocardia species for 15 antibiotics were determined by the broth microdilution method. Among these Nocardia isolates, Nocardia farcinica was the most commonly isolated species (39.9%, 176 of 441), followed by Nocardia cyriacigeorgica (28.6%, 126), Nocardia abscessus (6.6%, 29), and Nocardia otitidiscaviarum (5.9%, 26). Furthermore, 361 Nocardia strains (81.9%) were collected from lower respiratory tract (sputum, lung tissue, and bronchoalveolar lavage fluid), 50 (11.3%) were collected from skin and soft tissues, 9 were collected from blood, 9 were collected from eye, 4 were collected from cerebrospinal fluid and brain abscesses, and 2 were collected from pleural effusion. All of the Nocardia strains were susceptible to linezolid, followed by amikacin (99.3%) and trimethoprim-sulfamethoxazole (TMP-SMX) (99.1%). The antibiotic resistance profiles of other antibiotics varied tremendously among different Nocardia species. This demonstrated that accurate species identification and/or antibiotic susceptibility testing should be performed before the usage of these antibiotics. In summary, this is the largest study on the species and antibiotic resistance profiles of the genus Nocardia circulating in China, and our data will contribute to a better understanding of clinical nocardiosis. IMPORTANCE The genus Nocardia has the potential to cause nocardiosis, which might be underrecognized and underdiagnosed. Herein, the demographical features of 441 nonrepetitive nocardiosis cases and species distribution of their Nocardia strains in China, 2009 to 2021, are summarized. The susceptibility profiles for 15 antibiotics against all of the above Nocardia strains were also determined by the broth microdilution method. To date, this is the largest study on the genus Nocardia contributing to nocardiosis in China. Our study will be helpful for understanding the species diversity of Nocardia isolates distributed in China and for decision-making in the context of nocardiosis diagnosis and treatment.

Asunto(s)

Nocardiosis , Nocardia , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Secuencia de Bases , Farmacorresistencia Bacteriana/genética , Humanos , Nocardia/genética , Nocardiosis/tratamiento farmacológico , Nocardiosis/epidemiología , Nocardiosis/genética

RESUMEN

BACKGROUND: Nocardia species belong to the aerobic actinomycetes group of bacteria which are gram-positive and partially acid-fast Bacilli. These bacteria may sometimes be associated with nosocomial infections. Nocardia diseases are not required to be reported to public health authorities in Iran. Hence, the present study was designed to determine the prevalence of human Nocardia spp. in Iran by using a systematic review and meta-analysis according to the preferred reporting items for systematic reviews and meta-Analyses statement. METHODS: The data of the prevalence of Nocardia species were collected from databases such as Embase, PubMed/MEDLINE via Ovid, Web of Science, Scopus and Google Scholar as well as national Iranian databases, including SID, Magiran. Analyses were conducted by STATA 14.0. RESULTS: The meta-analyses showed that the proportion of Nocardia spp. in Iranian studies varied from 1.71(1.17, 2.24) to 0.46(0.09, 0.83). N. asteroides (21% [95% CI 1.17, 2.24]), N. cyriacigeorgica (17% [95% CI 0.99, 1.77]), N. facanica (10% [95% CI 0.75, 1.00]) were considered to be common causative agents. CONCLUSIONS: Our study presents that despite the fact that Nocardia spp. are normally are saprophytic organisms, are currently accounts as emerging pathogens due to an increase in immunocompromised patients among Iranian populations. Considering our results, the establishment of advanced diagnostic facilities for the rapid detection of Nocardia infections are required for optimal therapeutic strategies of Nocardia spp. in Iran. Our findings could help the programmatic management of the disease within the context of Nocardia control programs.

Asunto(s)

Genotipo , Nocardiosis/epidemiología , Nocardiosis/genética , Nocardia/genética , Femenino , Humanos , Irán/epidemiología , Masculino , Nocardia/patogenicidad , Prevalencia

Asunto(s)

Enfermedades Pulmonares Intersticiales/genética , Proteínas de la Membrana/genética , Enfermedades Vasculares/genética , Anticuerpos Anticitoplasma de Neutrófilos , Niño , Resultado Fatal , Femenino , Mutación con Ganancia de Función , Humanos , Insuficiencia Multiorgánica/genética , Nocardiosis/genética

RESUMEN

Interleukin-8 (IL-8, CXCL8), a pro-inflammatory chemokine secreted by a variety of cell types, plays a critical role in the development of various immune diseases. Interactions between IL-8 and its receptor CXC receptor 1/2 (CXCR1/2) are known to promote chemotaxis and phagocytosis in many immune responses. In this study, we report the molecular characteristics and pharmacological activity of CXCR1 (MsCXCR1) in largemouth bass (Micropterus salmoides) and evaluated the functional involvement of MsCXCR1 in individuals infected with the pathogen Nocardia seriolae. MsCXCR1 was cloned into the pEGFP-N1 plasmid and the subcellular localization of MsCXCR1 on the cell membrane was verified in MsCXCR1-EGFP-expressing HEK293 cells. Following observation of receptor internalization and intracellular signaling detection, we further determined the functional interaction of secreted interleukin-8 (LcIL-8, the ligand for CXCR1 in large yellow croaker) and MsCXCR1 was further determined, and the ERK phosphorylation signal activation mediated by MsCXCR1 was demonstrated. Quantitative real-time PCR assays were conducted to analyze the transcriptional distribution of MsCXCR1 in various tissues of healthy and diseased largemouth bass. These results illustrate the significant elevation of MsCXCR1 expression in the head kidney, spleen and liver of M. salmoides, suggesting that MsCXCR1 was involved in the immune response in N. seriolae-infected largemouth bass and potentially affects the digestive function of this species.

Asunto(s)

Lubina/microbiología , Enfermedades de los Peces/genética , Enfermedades de los Peces/microbiología , Nocardiosis/microbiología , Nocardiosis/veterinaria , Nocardia/fisiología , Receptores de Interleucina-8A/metabolismo , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Lubina/anatomía & histología , Lubina/genética , Endocitosis , Activación Enzimática , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Enfermedades de los Peces/patología , Proteínas Fluorescentes Verdes/metabolismo , Células HEK293 , Humanos , Interleucina-8/metabolismo , Nocardiosis/genética , Nocardiosis/patología , Fosforilación/efectos de los fármacos , Filogenia , Receptores de Interleucina-8A/química , Receptores de Interleucina-8A/genética , Transcripción Genética

RESUMEN

We describe here the isolation and characterization of the bacteriophage, NTR1 from activated sludge. This phage is lytic for Nocardia transvalensis, Nocardia brasiliensis and Nocardia farcinica. NTR1 phage has a genome sequence of 65,275 bp in length, and its closest match is to the Skermania piniformis phage SPI1 sharing over 36% of its genome. The phage belongs to the Siphoviridae family, possessing a long non-contractile tail and icosahedral head. Annotation of the genome reveals 97 putative open reading frames arranged in the characteristic modular organization of Siphoviridae phages and contains a single tRNA-Met gene.

Asunto(s)

Bacteriófagos/genética , Nocardiosis/virología , Nocardia/virología , Siphoviridae/genética , Bacteriófagos/aislamiento & purificación , ADN Viral/genética , Genoma Viral/genética , Nocardia/genética , Nocardia/patogenicidad , Nocardiosis/genética , Nocardiosis/microbiología , Filogenia , Aguas del Alcantarillado/microbiología , Aguas del Alcantarillado/virología

RESUMEN

Hybrid snakehead fish (Channa maculata ♀ × Channa argus ♂), a new species used in freshwater aquaculture in China, is the common host of an epizootic bacterial infection by Nocardia seriolae. However, the information on the functions and mechanisms of hybrid snakehead immune pathways with the N. seriolae infection is limited. Thus, the peripheral blood lymphocytes from hybrid snakehead were used for transcriptome analysis to understand the host immune response after challenge with N. seriolae. A total of 49,839,332 and 50,059,283 raw reads were obtained from the N. seriolae-challenged group (Ns group) and phosphate-buffered saline control group (Ctr group), respectively. The 75.50% and 74.25% reads from the Ns and Ctr groups were matched to reference genomic sequence after cleaning the raw reads, respectively. Additionally, there were 2892 significant differentially expressed genes (DEGs) among the 17,196 expressed genes between the Ns and Ctr groups, including 1387 upregulated and 1505 downregulated genes. All the DEGs were classified into three gene ontology categories, and 2502 DEGs had significant matches, which were allocated to 246 Kyoto Encyclopedia of Genes and Genomes pathways. Immune-related genes were detected from immune system pathways among the top 20 enriched pathways. Moreover, the regulation of several observed effective genes was confirmed by real-time quantitative polymerase chain reaction. Altogether, this study offers deep-sequence data of hybrid snakehead peripheral blood lymphocyte via transcriptome analysis and lays the foundation for further study on the immunogenetics of hybrid snakehead. Moreover, it provides insights into the pathogenic mechanism of N. seriolae, facilitating the prevention and treatment of fish nocardiosis.

Asunto(s)

Enfermedades de los Peces , Peces , Nocardiosis , Animales , Enfermedades de los Peces/genética , Enfermedades de los Peces/inmunología , Peces/genética , Peces/inmunología , Perfilación de la Expresión Génica , Nocardiosis/genética , Nocardiosis/inmunología , Nocardiosis/veterinaria , Transcriptoma/inmunología

RESUMEN

This study aims at genetic characterization and phylogenetic relationships of Nocardia brasiliensis focusing by using housekeeping rrs, hsp65, and sodA genes. N. brasiliensis is the species responsible for 80% of cases of actinomycetoma, one form of cutaneous nocardiosis which occurs mainly in tropical regions reaching immunocompetent patients in which the disease can lead to amputation. We analyze 36 indigenous cases of N. brasiliensis that happened in France. Phylogenetic analysis targeting rrs gene showed no robustness at phylogenetic nodes level. However, the use of a concatenation of hsp65 and sodA genes showed that the tested strains surprisingly ranked in 3 well-defined genotypes. Genotypes 2 and 3 were phylogenetically closer to each other and both diverged from genotype 1 sustained by a high bootstrap of 81%. This last genotype hosts all the cases of pulmonary forms (3), the sole cerebral form, and almost all the cases of immunocompromised patients (3 out of 4). Moreover, excepting one of them, all the strains belonging to this group present a susceptibility to imipenem which is not the case in the other genotypes that rarely count among them strains being susceptible to this drug. The haplotype diversity (Hd) of hsp65 (0.927) and sodA (0.885) genes was higher than that of rrs (0.824). For this gene, we obtained 16 polymorphic sites whereas, for hsp65 and sodA genes, up to 27 and 29 were identified, respectively. This study reveals that these two genes have an important genetic discriminatory power for the evaluation of the intraspecies genetic variability of N. brasiliensis and they may be useful for identification purposes at species level. This study also reveals the possible existence of a new species harbored by genotype 1.

Asunto(s)

Proteínas Bacterianas/genética , Variación Genética , Nocardiosis/genética , Superóxido Dismutasa-1/genética , Francia/epidemiología , Humanos , Nocardia/genética , Nocardia/patogenicidad , Nocardiosis/epidemiología , Nocardiosis/microbiología , Nocardiosis/patología , Filogenia

RESUMEN

CASE HISTORY: An investigation was conducted to identify the cause of mortalities in freshwater reared Chinook salmon (Oncorhynchus tshawytscha). Mortalities occurred in juvenile salmon, at a salmon rearing facility in the South Island of New Zealand. The affected fish were from a pen inside the facility with no surrounding pens or other year classes affected. CLINICAL FINDINGS: Clinically affected fish presented with skin lesions. The majority of skin lesions were unruptured, boil-like, raised circular masses up to 4 cm in diameter, particularly on the dorsolateral aspects and the flank. A number of fish presented with large ulcers resulting from rupturing of the raised lesions described above. This clinical presentation showed similarities to that of furunculosis caused by typical Aeromonas salmonicida, a bacterium exotic to New Zealand. LABORATORY FINDINGS: Samples were taken from two representative fish in the field for histopathology, bacterial culture and molecular testing. Histopathological findings included granulomatous lesions in the kidney, liver, spleen and muscle. When stained with Fite-Faraco modified acid fast stain filamentous branching rods were identified within these granulomas. Following bacterial culture of kidney swabs pure growth of small white matt adherent colonies was observed. This isolate was identified as a Nocardia species by biochemical testing and nucleotide sequencing of the partial 16S rRNA gene. All samples were negative for A. salmonicida based on bacterial culture and PCR testing. DIAGNOSIS: Nocardiosis caused by a Nocardia species. CLINICAL RELEVANCE: Nocardiosis in these fish was caused by a previously undescribed Nocardia species that differs from the species known to be pathogenic to fish: N. asteroides, N. salmonicida and N. seriole. This bacterium is likely to be a new or unnamed environmental species of Nocardia that has the potential to cause disease in Chinook salmon under certain conditions. The clinical presentation of this Nocardia species manifested as raised, boil-like skin lesions which has similarities to the presentation of furunculosis caused by the bacterium typical A. salmonicida, a species exotic to New Zealand.

Asunto(s)

Enfermedades de los Peces/microbiología , Nocardiosis/veterinaria , Nocardia/aislamiento & purificación , Salmón/microbiología , Animales , Bases de Datos de Ácidos Nucleicos , Enfermedades de los Peces/genética , Enfermedades de los Peces/patología , Agua Dulce , Genes de ARNr , Nueva Zelanda , Nocardia/genética , Nocardiosis/genética , Nocardiosis/patología , Reacción en Cadena de la Polimerasa

RESUMEN

Nocardiosis caused by Nocardia seriolae is one of the major threats in the aquaculture of Seriola species (yellowtail; S. quinqueradiata, amberjack; S. dumerili and kingfish; S. lalandi) in Japan. Here, we report the complete nucleotide genome sequence of N. seriolae UTF1, isolated from a cultured yellowtail. The genome is a circular chromosome of 8,121,733 bp with a G+C content of 68.1% that encodes 7,697 predicted proteins. In the N. seriolae UTF1 predicted genes, we found orthologs of virulence factors of pathogenic mycobacteria and human clinical Nocardia isolates involved in host cell invasion, modulation of phagocyte function and survival inside the macrophages. The virulence factor candidates provide an essential basis for understanding their pathogenic mechanisms at the molecular level by the fish nocardiosis research community in future studies. We also found many potential antibiotic resistance genes on the N. seriolae UTF1 chromosome. Comparative analysis with the four existing complete genomes, N. farcinica IFM 10152, N. brasiliensis HUJEG-1 and N. cyriacigeorgica GUH-2 and N. nova SH22a, revealed that 2,745 orthologous genes were present in all five Nocardia genomes (core genes) and 1,982 genes were unique to N. seriolae UTF1. In particular, the N. seriolae UTF1 genome contains a greater number of mobile elements and genes of unknown function that comprise the differences in structure and gene content from the other Nocardia genomes. In addition, a lot of the N. seriolae UTF1-specific genes were assigned to the ABC transport system. Because of limited resources in ocean environments, these N. seriolae UTF1 specific ABC transporters might facilitate adaptation strategies essential for marine environment survival. Thus, the availability of the complete N. seriolae UTF1 genome sequence will provide a valuable resource for comparative genomic studies of N. seriolae isolates, as well as provide new insights into the ecological and functional diversity of the genus Nocardia.

Asunto(s)

Enfermedades de los Peces/microbiología , Genoma , Nocardiosis/genética , Nocardia/genética , Animales , Mapeo Cromosómico , Enfermedades de los Peces/genética , Peces/microbiología , Japón , Anotación de Secuencia Molecular , Nocardia/patogenicidad , Nocardiosis/microbiología , Filogenia

RESUMEN

In the present study, IL-1ß cDNA was identified and analyzed from largemouth bass (Micropterus salmoides). Full length IL-1ß mRNA was obtained using Rapid Amplification of cDNA Ends (RACE), which contains 78 bp 3'-UTR, a 455 bp 5'-UTR, and an open reading frame (ORF) of 702 bp coding for 233 amino acid residues. The molecular weight and theoretical isoelectric point of largemouth bass IL-1ß protein was predicted to be 26.7 kDa and 6.08 respectively. A largemouth bass IL-1ß phylogenetic analysis showed a close relation to the IL-1ßs of striped trumpeter (Latris lineata), Chinese perch (Siniperca chuatsi), and Japanese sea bass (Lateolabrax japonicus). Peptidoglycan upregulated IL-1ß in the spleen and head kidney, while lipopolysaccharide upregulated detectable levels of IL-1ß in the spleen only. Largemouth bass, challenged with Nocardia seriolae (1.0 × 106 cfu/mL), showed a significant increase in IL-1ß at 3 and 5 days post infection (dpi) in the spleen, while in the head kidney significant expression was found at 2 and 3 dpi, peaking at 3 dpi. Furthermore, tumor necrosis factor α (TNF-α) showed significantly higher expression in the spleen at 3 and 5 dpi, and in the head kidney at 1 and 3 dpi, with expression decreasing at 5 dpi in both tissues.

Asunto(s)

Lubina/genética , Lubina/inmunología , Enfermedades de los Peces/inmunología , Regulación de la Expresión Génica , Interleucina-1beta/metabolismo , Nocardiosis/veterinaria , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Lubina/clasificación , Clonación Molecular , ADN Complementario/genética , ADN Complementario/metabolismo , Enfermedades de los Peces/genética , Humanos , Interleucina-1beta/genética , Riñón/metabolismo , Ratones , Nocardia/inmunología , Nocardiosis/genética , Nocardiosis/inmunología , Filogenia , Estructura Secundaria de Proteína , Ratas , Alineación de Secuencia , Bazo/metabolismo , Transcriptoma , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismo

RESUMEN

Marine actinomycete-derived natural products continue to inspire chemical and biological investigations. Nocardioazines A and B (3 and 4), from Nocardiopsis sp. CMB-M0232, are structurally unique alkaloids featuring a 2,5-diketopiperazine (DKP) core functionalized with indole C3-prenyl as well as indole C3- and N-methyl groups. The logic of their assembly remains cryptic. Bioinformatics analyses of the Nocardiopsis sp. CMB-M0232 draft genome afforded the noz cluster, split across two regions of the genome, and encoding putative open reading frames with roles in nocardioazine biosynthesis, including cyclodipeptide synthase (CDPS), prenyltransferase, methyltransferase, and cytochrome P450 homologs. Heterologous expression of a twelve gene contig from the noz cluster in Streptomyces coelicolor resulted in accumulation of cyclo-l-Trp-l-Trp DKP (5). This experimentally connected the noz cluster to indole alkaloid natural product biosynthesis. Results from bioinformatics analyses of the noz pathway along with challenges in actinomycete genetics prompted us to use asymmetric synthesis and mass spectrometry to determine biosynthetic intermediates in the noz pathway. The structures of hypothesized biosynthetic intermediates 5 and 12-17 were firmly established through chemical synthesis. LC-MS and MS-MS comparison of these synthetic compounds with metabolites present in chemical extracts from Nocardiopsis sp. CMB-M0232 revealed which of these hypothesized intermediates were relevant in the nocardioazine biosynthetic pathway. This established the early and mid-stages of the biosynthetic pathway, demonstrating that Nocardiopsis performs indole C3-methylation prior to indole C3-normal prenylation and indole N1'-methylation in nocardioazine B assembly. These results highlight the utility of merging bioinformatics analyses, asymmetric synthetic approaches, and mass spectrometric metabolite profiling in probing natural product biosynthesis.

Asunto(s)

Dicetopiperazinas/metabolismo , Genómica , Análisis de Secuencia , Dicetopiperazinas/química , Genoma Bacteriano/genética , Modelos Moleculares , Conformación Molecular , Familia de Multigenes/genética , Nocardiosis/enzimología , Nocardiosis/genética , Nocardiosis/metabolismo , Péptido Sintasas/genética , Péptido Sintasas/metabolismo , Espectrometría de Masas en Tándem

RESUMEN

The actinomycete Nocardiopsis alba was reportedly associated with honeybees in separate occurrences. We report the complete genome of Nocardiopsis alba ATCC BAA-2165 isolated from honeybee guts. It will provide insights into the metabolism and genetic regulatory networks of this genus of bacteria that enable them to live in a range of environments.

Asunto(s)

Abejas/microbiología , Genoma Bacteriano , Nocardiosis/clasificación , Nocardiosis/genética , Animales , Datos de Secuencia Molecular