RESUMO
Strain T-12T, an orange, Gram-stain-negative, non-motile, rod-shaped strain, was isolated in November 2013 from water samples collected from an Atlantic salmon (Salmo salar) fry culturing system at a fish farm in Chile. Phylogenetic analysis based on 16S rRNA sequences (1394 bp) revealed that strain T-12T belonged to the genus Flavobacterium, showing close relationships to Flavobacterium bernardetii F-372T (99.48â%) and Flavobacterium terrigena DS-20T (98.50â%). The genome size of strain T-12T was 3.28 Mb, with a G+C content of 31.1âmol%. Genome comparisons aligned strain T-12T with Flavobacterium bernardetii F-372T (GCA_011305415) and Flavobacterium terrigena DSM 17934T (GCA_900108955). The highest digital DNA-DNA hybridization (dDDH) values were 42.6â% with F. bernardetii F-372T (GCA_011305415) and 33.9â% with F. terrigena DSM 17934T (GCA_900108955). Pairwise average nucleotide identity (ANI) calculations were below the species cutoff, with the best results with F. bernardetii F-372T being: ANIb, 90.33â%; ANIm, 91.85â%; and TETRA, 0.997â%. These dDDH and ANI results confirm that strain T-12T represents a new species. The major fatty acids were iso-C15â:â0 and C15â:â1ω6Ñ. Detected polar lipids included phospholipids (n=2), aminophospholipid (n=1), aminolipid (n=1) and unidentified lipids (n=2). The predominant respiratory quinone was menaquinone MK7 (80â%) followed by MK-6 (20â%). Phenotypic, chemotaxonomic, and genomic data support the classification of strain T-12T (=CECT 30410T=RGM 3222T) as representing a novel species of Flavobacterium, for which the name Flavobacterium facile sp. nov. is proposed.
Assuntos
Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano , Ácidos Graxos , Flavobacterium , Hibridização de Ácido Nucleico , Filogenia , RNA Ribossômico 16S , Salmo salar , Análise de Sequência de DNA , Vitamina K 2 , Animais , Flavobacterium/genética , Flavobacterium/isolamento & purificação , Flavobacterium/classificação , RNA Ribossômico 16S/genética , Ácidos Graxos/análise , Salmo salar/microbiologia , DNA Bacteriano/genética , Chile , Vitamina K 2/análogos & derivados , Vitamina K 2/análise , Microbiologia da Água , Fosfolipídeos/análiseRESUMO
Strain LB-N7T, a novel Gram-negative, orange, translucent, gliding, rod-shaped bacterium, was isolated from water samples collected from an open system of Atlantic salmon (Salmo salar) smolts in a fish farm in Chile during a flavobacterial infection outbreak in 2015. Phylogenetic analysis based on 16S rRNA sequences (1337 bp) revealed that strain LB-N7T belongs to the genus Flavobacterium and is closely related to the type strains Flavobacterium ardleyense A2-1T (98.8â%) and Flavobacterium cucumis R2A45-3T (96.75â%). The genome size of strain LB-N7T was 2.93 Mb with a DNA G+C content 32.6 mol%. Genome comparisons grouped strain LB-N7T with Flavobacterium cheniae NJ-26T, Flavobacterium odoriferum HXWNR29T, Flavobacterium lacisediminis TH16-21T and Flavobacterium celericrescens TWA-26T. The calculated digital DNA-DNA hybridization values between strain LB-N7T and the closest related Flavobacterium strains were 23.3â% and the average nucleotide identity values ranged from 71.52 to 79.39â%. Menaquinone MK-6 was the predominant respiratory quinone, followed by MK-7. The major fatty acids were iso-C15â:â0 and anteiso-C15â:â0. The primary polar lipids detected included nine unidentified lipids, two amounts of aminopospholipid and phospholipids, and a smaller amount of aminolipid. Phenotypic, genomic, and chemotaxonomic data suggest that strain LB-N7T (=CECT 30406T=RGM 3221T) represents as a novel bacterial species, for which the name Flavobacterium psychraquaticum sp. nov. is proposed.
Assuntos
Flavobacterium , Salmo salar , Animais , Flavobacterium/genética , Chile , Filogenia , RNA Ribossômico 16S/genética , Composição de Bases , Ácidos Graxos/química , Análise de Sequência de DNA , DNA Bacteriano/genética , Técnicas de Tipagem BacterianaRESUMO
Strain I-SCBP12nT, a novel Gram-stain-negative, aerobic, non-spore-forming, motile-by-gliding and rod-shaped bacterium, was isolated from a chinstrap penguin chick (Pygoscelis antarcticus) during a 2015 expedition to the Chilean Antarctic territory. Phylogenetic analysis based on 16S rRNA gene sequencing confirmed that strain I-SCBP12nT belonged to the genus Flavobacterium, being closely related to strains Flavobacterium chryseum P3160T (98.52â%), Flavobacterium hercynium WB 4.2-33T (98.47â%) and Flavobacterium chilense LM-19-FpT (98.47â%). The genome size of strain I-SCBP12nT was 3.69 Mb with DNA G+C content 31.95 mol%. Genomic comparisons of strain I-SCBP12nT with type species in the genus Flavobacterium were performed, with obtained average values near 75.17 and 84.33â% for the blast and MUMer analyses of average nucleotide identity, respectively, and 0.86 for the tetranucleotides frequency analysis. These values are far from the accepted species cut-off values. Strain I-SCBP12nT contained MK-6 as the predominant menaquinone and the major polar lipids were aminophospholipid, an unidentified aminolipid and unidentified lipids. The predominant fatty acids (> 5â%) were iso-C14â:â0, iso-C15â:â0, anteiso-C15â:â0, iso-C16â:â0, iso-C16â:â1, iso-C16â:â0 3-OH, C15â:â1 ω6c and summed feature 3 (C16â:â1 ω7c/C16â:â1 ω6c). Phenotypic, chemotaxonomic and genomic data supported the assignment of strain I-SCBP12nT (=CECT 30404T=RGM 3223T) to a novel species of Flavobacterium, for which the name Flavobacterium pygoscelis sp. nov.is proposed.
Assuntos
Ácidos Graxos , Spheniscidae , Animais , Ácidos Graxos/química , Flavobacterium , Filogenia , RNA Ribossômico 16S/genética , DNA Bacteriano/genética , Análise de Sequência de DNA , Composição de Bases , Técnicas de Tipagem Bacteriana , Vitamina K 2RESUMO
Botrytis cinerea is a phytopathogenic fungus that infects over 200 plant species and can cause significant crop losses in local and worldwide agricultural industries. However, its presence in the endemic flora in the Coquimbo Region and its impact on local flora have not been studied yet. In order to determine whether Botrytis spp is present in the native plant in the Coquimbo Region, fifty-two field-samples were analysed. A total of 30 putative Botrytis spp were isolated and phenotypic and genetically characterized. The internal transcribed spacer (ITS) analysis of these isolates revealed that it corresponded to genus Botrytis. For further confirmation, nuclear protein-coding genes (G3PDH, HSP60, and RPB2) were sequenced and showed 100% identity against B. cinerea. Complementary to this, Botrytis can also be clustered in two different groups, group I (B. pseudocinerea) and group II (B. cinerea), based on DNA polymorphism, the Botrytis isolates were identified as member of group II. On the order hand, we investigated the presence and frequency distribution of the transposable elements boty and flipper in the isolates obtained. The results indicate that 83.3% of the isolates presented both transposable elements, boty and flipper, indicating that the most prevalent genotype was transpose. In addition, 16.6% of the isolates showed substantially reduced virulence in apple fruit in comparison to B05.10 strain. According to fungicide resistance studies, the results indicate that resistance to Fenhexamid or Boscalid was observed in the 22.6% of isolates. The results show for the first time that B. cinerea has not been described before in fourteen new host plants and contributes to our fundamental understanding of the presence of B. cinerea in the native plant in the Coquimbo Region and the possible ecological impact of this disease on native and endemic plants.
RESUMO
The air humidity in Antarctica is very low and this peculiar weather parameter make the use of flame retardants in research facilities highly needed for safety reasons, as fires are a major risk. Legacy and novel flame retardants (nFRs) including polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), Dechlorane Plus (DP), and other nFRs were measured in indoor dust samples collected at research Stations in Antarctica: Gabriel de Castilla, Spain (GCS), Julio Escudero, Chile (JES), and onboard the RRS James Clark Ross, United Kingdom (RRS JCR). The GC-HRMS and LC-MS-MS analyses of dust samples revealed ∑7PBDEs of 41.5 ± 43.8 ng/g in rooms at GCS, 18.7 ± 11.6 ng/g at JES, and 27.2 ± 37.9 ng/g onboard the RRS JCR. PBDE pattern was different between the sites and most abundant congeners were BDE-183 (40%) at GCS, BDE-99 (50%) at JES, and BDE-153 (37%) onboard the RRS JCR. The ∑(4)HBCDs were 257 ± 407 ng/g, 14.9 ± 14.5 ng/g, and 761 ± 1043 ng/g in indoor dust collected in rooms at GCS, JES, and RRS JCR, respectively. The ∑9nFRs were 224 ± 178 ng/g at GCS, 14.1 ± 13.8 ng/g at JES, and 194 ± 392 ng/g on the RRS JCR. Syn- and anti-DP were detected in most of the samples and both isomers showed the highest concentrations at GCS: 163 ± 93.6 and 48.5 ± 61.1 ng/g, respectively. The laboratory and living room showed the highest concentration of HBCDs, DPs, BTBPE. The wide variations in FR levels in dust from the three research facilities and between differently used rooms reflect the different origin of furnishing, building materials and equipment. The potential health risk associated to a daily exposure via dust ingestion was assessed for selected FRs: BDEs 47, 99, and 153, α-, ß-, and γ-HBCD, BTBPE, syn- and anti-DP. Although the estimated exposures are below the available reference doses, caution is needed given the expected increasing use of novel chemicals without a comprehensive toxicological profile.
Assuntos
Poluição do Ar em Ambientes Fechados , Retardadores de Chama , Poluição do Ar em Ambientes Fechados/análise , Regiões Antárticas , Chile , Poeira/análise , Exposição Ambiental/análise , Monitoramento Ambiental , Retardadores de Chama/análise , Éteres Difenil Halogenados/análise , Humanos , Espanha , Reino UnidoRESUMO
The bacterial strain M7D1T was isolated from samples of the rhizosphere of desert bloom plants on the Atacama region located in northern Chile as part of a study intended to isolate nitrifying bacteria in this adverse environment. It was previously identified as belonging to the Pseudomonas fluorescens group. In this study, the phylogenetic analysis of the 16s RNA, gyrA, rpoB and rpoD genes confirmed that this strain belongs to this group, especially Sub Group (SG) Koreensis, but it represents a potential new species. Additionally, the average nucleotide identity confirmed this as the highest identity value (0.92) with Pseudomonas moraviensis LMG 24280, which is lower than the 0.94 threshold established to classify two strains within the same species. The strain M7D1T shared a similar fatty acids methyl ester profile than the type strains of other Pseudomonas spp. previously described. Furthermore, it can be differentiated phenotypically from other related species of SG P. koreensis. Based on these results, the existence of a new species of Pseudomonas is demonstrated, for which the name Pseudomonas atacamensis is proposed. This strain presented a set of genes associated with plant growth-promoting rhizobacteria and it is a good candidate to be used for recovery of contaminated soils. However, more studies are required to demonstrate whether this bacterium is non-pathogenic, can survive in the presence of toxic compounds and promote growth or help to the stress management of plants.
Assuntos
Filogenia , Pseudomonas/classificação , Pseudomonas/isolamento & purificação , Rizosfera , Microbiologia do Solo , Técnicas de Tipagem Bacteriana , Composição de Bases , Chile , DNA Bacteriano/genética , Ácidos Graxos/análise , Genes Bacterianos/genética , Genoma Bacteriano , Hibridização de Ácido Nucleico , Pseudomonas/citologia , Pseudomonas/genética , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Here, we announce the draft genome sequence of Pseudomonas sp. strain AN3A02, isolated from the rhizosphere of one of the only two species of vascular plants existing in the Antarctic continent, Deschampsia antarctica Desv. This isolate, which inhibited the mycelial growth of Botrytis cinerea in dual culture, has a genome sequence of 6,778,644 bp, with a G+C content of 60.4%. These draft genome sequence data provide insight into the genetics underpinning the antifungal activity of this strain.
RESUMO
Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease and rainbow trout syndrome in freshwater salmonid fish worldwide, generating injuries and high mortality rates. Despite several studies on this bacterium, the infection mechanism remains unknown due to limitations in the employed animal models. In this work, we propose using zebrafish (Danio rerio) as a model for studying bacterial pathogenicity. To substantiate this proposal, zebrafish infection by F. psychrophilum strain JIP 02/86 was characterized. Zebrafish larvae were infected using the bath method, and morphological changes and innate immune system activation were monitored using transgenic fish. Salmonid-like infection phenotypes were observed in 4.74% of treated larvae, as manifested by fin, muscle and caudal peduncle damage. Symptomatic and dead larvae accounted for 1.35% of all challenged larvae. Interestingly, infected larvae with no infection phenotypes showed stronger innate immune system activation than specimens with phenotypes. A failure of function assay for myeloid factor pu.1 resulted in more infected larvae (up to 43.5%), suggesting that low infection rates by F. psychrophilum would be due to the protective actions of the innate immune system against this bacterium in zebrafish larvae. Our results support the use of zebrafish as an infection model for studying F. psychrophilum. Furthermore, the percentage of infected fish can be modulated by disturbing, to varying extents, the differentiation of myeloid cells. Using this evidence as a starting point, different aspects of the infection mechanism of F. psychrophilum could be studied in vivo.
Assuntos
Modelos Animais de Doenças , Doenças dos Peixes/microbiologia , Infecções por Flavobacteriaceae/veterinária , Flavobacterium/fisiologia , Peixe-Zebra , Animais , Infecções por Flavobacteriaceae/microbiologiaRESUMO
We announce the draft genome sequence of strain B2, which belongs to a potentially new Buttiauxella species, isolated from soil associated with rhizosphere of olivillo trees (Aextoxicon punctatum). Its size is 4,967,099 bp, and its G+C content is 49.1%. The genome of strain B2 carries genes related to rhizobacteria that promote the growth of plants.
RESUMO
A Gram-stain positive, pleomorphic, oxidase-negative, non-motile isolate from the ulcer of a farmed Atlantic salmon (Salmo salar), designated strain T11bT, was subjected to a comprehensive taxonomic investigation. A comparative analysis of the 16S rRNA gene sequence showed highest similarities to the type strains of Pseudarthrobacter siccitolerans (98.1â%) and Arthrobacter methylotrophus and Pseudarthrobacter phenanthrenivorans (both 98.0â%). The highest ANI value observed between the assembled genome of T11bT and the publicly available Pseudarthrobacter and Arthrobacter type strain genomes were 81.15 and 80.99â%, respectively. The major respiratory quinone was menaquinone MK-9(H2). The polyamine pattern contained predominantly spermidine. The polar lipid profile consisted of the major lipids diphosphatidylglycerol, phosphatidylglycerol, monogalactosyl-diacylglycerol and dimannosylglyceride. Minor amouts of trimannosyldiacylglycerol and phosphatidylinositol were also detected. The peptidoglycan was of the type A3α l-Lys-l-Ser-l-Thr-l-Ala (A11.23). In the fatty acid profile, anteiso and iso branched fatty acids predominated (anteiso C15â:â0, iso C16â:â0, anteiso C17â:â0). Moderate to low DNA-DNA similarities, physiological traits as well as unique traits in the fatty acid pattern distinguished strain T11bT from the next related species. All these data point to the fact that strain T11bT represents a novel species of the genus Arthrobacter for which we propose the name Arthrobacter ulcerisalmonis sp. nov. The type strain is T11bT (=CIP 111621T=CCM 8854T=LMG 30632T=DSM 107127T).
Assuntos
Arthrobacter/classificação , Doenças dos Peixes/microbiologia , Filogenia , Salmo salar/microbiologia , Úlcera/microbiologia , Animais , Aquicultura , Arthrobacter/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , Chile , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Peptidoglicano/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
One slightly beige-white pigmented, Gram-stain-negative, rod-shaped bacterium, strain I-STPP5bT, was isolated from the trachea of a Gentoo penguin chick individual (Pygoscelin papua) investigated in Fildes Bay, Chilean Antarctic (62° 12' S, 58° 57' W). I-STPP5bT consists of a 3.4 Mb chromosome with a DNA G+C content of 44.4 mol%. Of the 3056 predicted genes, 1206 were annotated as hypothetical proteins and 51 were tRNAs. Phylogenetic analysis based on nearly full-length 16S rRNA gene sequences showed that the isolate shared a 16S rRNA gene sequence identity to the type strains of Psychrobacter phenylpyruvicus (98.8â%), Psychrobacter arenosus and Psychrobacter pasteurii (both 98.3â%), Psychrobacter piechaudii (98.2â%) and Psychrobacter sanguinis (98.1â%), but 16S rRNA gene sequence similarities to all other Psychrobacter species were ≤98.0â%. Partial gyrB nucleotide and amino acid sequence similarities among strain STPP5bT and the next related type strains were all below 81.8 and 92.9%, respectively. DNA-DNA hybridisation (DDH) with P. phenylpyruvicus LMG 5372T, P. arenosus DSM 15389T and P. sanguinis DSM 23635T also showed low values (all below 30â%). The main cellular fatty acids of the strain were C18â:â1ω9c and C16â:â1ω7c and/or C16â:â1ω6c. Based on phylogenetic, chemotaxonomic, genomic and phenotypic analyses we propose a new species of the genus Psychrobacter, with the name Psychrobacter pygoscelis sp. nov. and strain I-STPP5bT (=CIP 111410T= CCM 8799T=LMG 30301T) as type strain.
Assuntos
Filogenia , Psychrobacter/classificação , Spheniscidae/microbiologia , Traqueia/microbiologia , Animais , Regiões Antárticas , Técnicas de Tipagem Bacteriana , Composição de Bases , Chile , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Psychrobacter/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Vibrio ordalii is an extracellular, Gram-negative bacterium that produces vibriosis in salmonids. While pathogenesis is not fully understood, this bacterium has numerous likely genes for adhesion, colonization, invasion factors and, as recently suggested, intracellular behaviour. Therefore, this study aimed to clarify possible intracellular behaviour for V. ordalii Vo-LM-18 and ATCC 33509T in the fish-cell lines SHK-1 and CHSE-214. Confocal microscopy revealed Vo-LM-18 and ATCC 33509T inside cytoplasm in both fish-cell lines at 4 hr post-inoculation (hpi). At 8 and 16 hpi, the proportion of fish cells invaded by both strains increased. Moreover, intracellular V. ordalii were observed after 8 hpi inside mouse embryonic fibroblasts (MEF), demonstrating that entry was not due to a cellular phagocytosis process. Flow cytometry confirmed immunocytochemistry results, with both V. ordalii evidencing statistically significant differences in the number of infected cells between 8 and 16 hpi. Interestingly, V. ordalii infection did not significantly damage fish cells, as determined by LDH liberation. Viable counts at 8 hpi detected, on average for both lines, 176 ± 47 CFU/ml of culturable intracellular Vo-LM-18 and ATCC 33509T cells. These in vitro findings support the facultative intracellular behaviour of V. ordalii and may be of importance for understanding pathogenicity and survival in aquatic environments.
Assuntos
Doenças dos Peixes/microbiologia , Salmão , Vibrioses/veterinária , Vibrio/fisiologia , Animais , Linhagem Celular , Citometria de Fluxo/veterinária , Técnica Indireta de Fluorescência para Anticorpo/veterinária , Microscopia Confocal/veterinária , Vibrioses/microbiologiaRESUMO
An orange-pigmented, oxidase-positive bacterial strain (I-41R45T), isolated from the kidney of a black rock cod fish sampled in the Chilean Antarctic was studied in a polyphasic taxonomic investigation. Cells of the isolate were coccoid and stained Gram-negative. A comparison of the 16S rRNA gene sequence of strain I-41R45T with sequences of type strains of most closely related Paracoccus species showed highest sequence similarities to Paracoccus hibiscisoli (98.4â%), Paracoccus marcusii (98.3â%), Paracoccus haeundaensis and Paracoccus carotinifaciens (both 98.2â%). 16S rRNA gene sequence similarities to all other Paracoccus species were below 97â%. The draft genome of strain I-41R45T had a size of 4.59 Mb with a DNA G+C content of 65.26 mol% and included the prediction and annotation of 4426 coding genes, 1973 protein-coding genes and 46 tRNAs. The fatty acid profile of strain I-41R45T consisted mainly of the major fatty acids C18â:â1 ω7c/ω9t/ω12t and C18:0, typical of the genus Paracoccus. DNA-DNA hybridizations between I-41R45T and type strains of P. hibiscisoli, P. marcusiiand P. haeundaensis resulted in similarity values of 45â% (reciprocal 26â%), 66â% (reciprocal 61â%), and 29â% (reciprocal 36â%), respectively. DNA-DNA hybridization results, together with the differentiating biochemical and chemotaxonomic properties, showed that strain I-41R45T represents a novel Paracoccus species, for which the name Paracoccus nototheniae sp. nov. (type strain I-41R45T=CCM 8875T=CIP 111632T), is proposed.
Assuntos
Rim/microbiologia , Paracoccus/classificação , Perciformes/microbiologia , Filogenia , Animais , Regiões Antárticas , Técnicas de Tipagem Bacteriana , Composição de Bases , Chile , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Paracoccus/isolamento & purificação , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
We announce the draft genome sequence of Pseudomonas sp. strain M7D1, isolated from the rhizosphere of a plant in the Atacama Desert bloom event. The genome sequence had 6,170,633 bp with a G+C content of 59.9%. This draft genome sequence gives information about the presence of genes related to iron acquisition, alleviation of abiotic stress, and other essential traits of plant growth-promoting rhizobacteria.
RESUMO
A pink pigmented, Gram-negative, rod-shaped, non-spore-forming bacterium (strain 36B243T), was isolated from the spleen of a black rock cod (Notothenia coriiceps, Richardson 1844) in the Chilean Antarctica. Strain 36B243T has a 5.26 Mb chromosome with a DNA G + C content of 35.4 mol%. The draft genome includes the prediction and annotation of 4585 coding genes, and 46 tRNA, 1 tmRNA, and 2735 hypothetical proteins. Phylogenetic analysis based on the 16S rRNA gene sequence placed strain 36B243T into the genus Pedobacter with high sequence similarity to the type strains of Pedobacter sandarakinus (97.5%) and Pedobacter petrophilus (97.1%). Sequence similarities to type strains of all other current Pedobacter species were below 97.1%. Predominant fatty acids are summed feature 3 (C16:1ω7c and/or C16:1ω6c) and iso-C15:0 followed by iso-C17:0 3-OH and C16:0. The major respiratory quinone was menaquinone MK-7. The polar lipid profile contained the major lipids phosphatidylethanolamine, five unidentified aminolipids, two lipids lacking a functional group and two minor glycolipids and one lipid lacking a functional group. An alkali-stable lipid was present. The polyamine pattern contained the predominant compound sym-homospermidine. Characterization by 16S rRNA gene sequence analysis, physiological parameters, pigment analysis, ubiquinone, polar lipid, and fatty acid composition revealed that strain 36B243T represents a new species of the genus Pedobacter. For this reason, we propose the name Pedobacter nototheniae sp. nov. with the type strain 36B243T (= LMG 30634T = CCM 8855T = CIP 111622T).
Assuntos
Pedobacter/classificação , Pedobacter/isolamento & purificação , Perciformes/microbiologia , Baço/microbiologia , Animais , Regiões Antárticas , Técnicas de Tipagem Bacteriana , Composição de Bases , Chile , Análise por Conglomerados , Citosol/química , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Ácidos Graxos/análise , Genoma Bacteriano , Glicolipídeos/análise , Pedobacter/genética , Pedobacter/fisiologia , Fosfolipídeos/análise , Filogenia , Pigmentos Biológicos/metabolismo , Quinonas/análise , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análiseRESUMO
Spring viraemia of carp (SVC) is an infectious disease responsible for severe economic losses for various cyprinid species, particularly common carp (Cyprinus carpio carpio). The causative agent is the SVC virus (SVCV), a member of the Sprivivirus genus, Rhabdoviridae family, and a List 1 pathogen notifiable by the World Organization for Animal Health. This study describes the diagnosis of an SVCV pathogen isolated in October 2015 from wild common carp inhabiting a natural lagoon in central Mexico. While neither an epidemic nor fish mortalities were reported, the collected killed specimens exhibited clinical signs of disease (e.g., exopthalmia, moderate abdominal distension and haemorrhaging, as well as internal haemorrhages and adhesions). Histological results of injuries were consistent with the pathology caused by SVCV. This finding was supported by the isolation of a virus in EPC and BF-2 cells and subsequent RT-PCR confirmation of SVCV. The phylogenetic analyses of partial SVCV glycoprotein gene sequences classified the isolates into the Ia genogroup. These findings make this the first report of SVCV detection in Mexico, extending the southern geographical range of SVCV within North America. However, since this pathogen was detected in fish inhabiting a natural body of water without tributaries or effluents, it is difficult to estimate the risk of SVCV for other wild/feral cohabitating cyprinid species in the lagoon. The status of this virus is also unknown for other bodies of water within this region.
Assuntos
Carpas , Doenças dos Peixes/diagnóstico , Infecções por Rhabdoviridae/veterinária , Rhabdoviridae/isolamento & purificação , Sepse/veterinária , Animais , Doenças dos Peixes/virologia , Glicoproteínas/análise , México , Filogenia , Infecções por Rhabdoviridae/diagnóstico , Infecções por Rhabdoviridae/virologia , Sepse/diagnóstico , Sepse/virologia , Proteínas Virais/análiseRESUMO
Weissella ceti, a Gram-positive nonmotile bacterium, is currently an emerging pathogen within rainbow trout (Oncorhynchus mykiss) farms in China, Brazil, the United States, and Japan. This study is the first to isolate, identify, and characterize W. ceti isolates from rainbow trout farmed in Mexico. In late 2015, a severe disease outbreak caused a 60% mortality rate among 20,000 fish. The diseased rainbow trout (100-300 g average) exhibited severe cachexia, body darkening, abdominal distension, exophthalmia, haemorrhages, and corneal opacity. Internally, diseased fish had pale gills; multifocal, disseminated whitish spots on the liver; haemorrhages in the swim bladder, ovary, and on the parietal surface of the muscle; and hearts with pseudo-membrane formation. Histologically, lesions were characterized by corneal oedema, degenerative and necrotic hepatitis, and meningitis. A brain (W-1) and kidney (W-2) isolate were identified as W. ceti through polyphasic taxonomy, which included phenotypic characterization and 16S rRNA sequencing. RAPD and ERIC-PCR analyses demonstrated genetic homogeneity among the Mexican isolates. Virulence tests in rainbow trout through intraperitoneal W. ceti injections at concentrations of 1 × 104 , 1 × 105 , and 1 × 106 CFU per fish resulted in cumulative mortality rates of 25%, 62.5%, and 87.5%, respectively, as well as the same clinical signs of hemorrhagic septicaemia as were recorded for the natural outbreak. The present report is the first to confirm the presence of W. ceti in Mexico, thus extending the known geographical distribution of this pathogen across the Americas.
Assuntos
Surtos de Doenças/veterinária , Doenças dos Peixes/epidemiologia , Infecções por Bactérias Gram-Positivas/veterinária , Oncorhynchus mykiss/microbiologia , Weissella/isolamento & purificação , Weissella/patogenicidade , Animais , Encéfalo/microbiologia , Feminino , Doenças dos Peixes/microbiologia , Infecções por Bactérias Gram-Positivas/epidemiologia , Infecções por Bactérias Gram-Positivas/microbiologia , Septicemia Hemorrágica/epidemiologia , Rim/microbiologia , México/epidemiologia , RNA Ribossômico 16S/genética , Técnica de Amplificação ao Acaso de DNA Polimórfico/veterinária , VirulênciaRESUMO
Flavobacterium psychrophilum is the etiologic agent of bacterial coldwater disease (BCWD) and rainbow trout fry syndrome (RTFS), which cause significant worldwide losses in aquaculture. Juvenile rainbow trout are particularly susceptible to F. psychrophilum infection, the main external clinical signs of which are extensive necrotic myositis and ulcerative lesions. Despite the economic relevance of this pathogen in aquaculture, little is known about the molecular mechanisms underlying F. psychrophilum infection and pathogenesis. In this study, cultured skeletal muscle cells from rainbow trout (Oncorhynchus mykiss) were co-incubated with the virulent strain of F. psychrophilum JIP02/86 (ATCC 49511). Trypan blue exclusion analysis at 48h post-incubation revealed decreased cellular viability. Direct bacteria-myoblast contact was found a key factor in inducing F. psychrophilum cytotoxicity. Apoptosis was characterized by nuclear DNA fragmentation, decreased plasma membrane integrity, increased caspase activity, and the proteolytic cleavage of poly(ADP-ribose)polymerase-1 (PARP-1). Moreover, bacterial infection induced an early inhibition of NF-κB signaling, as well as a differential expression of the pro- and anti-apoptotic genes, bax and bcl-2. These findings suggest that F. psychrophilum induces rainbow trout muscle apoptosis through the modulation of the NF-κB signaling as a mechanism for nutrient acquisition and survival.
Assuntos
Doenças dos Peixes/microbiologia , Infecções por Flavobacteriaceae/veterinária , Flavobacterium/fisiologia , Oncorhynchus mykiss/microbiologia , Animais , Apoptose , Aquicultura , Sobrevivência Celular , Infecções por Flavobacteriaceae/microbiologia , Músculo Esquelético/microbiologia , Mioblastos/microbiologiaRESUMO
A slightly beige-white pigmented, Gram-staining-negative, rod-shaped bacterium, strain M1A1T, was isolated from seawater samples obtained in Fildes Bay, Antarctica (62°12' S 58° 57' W). Phylogenetic analysis based on nearly full-length 16S rRNA gene sequences showed that the isolate shared 98.4â% 16S rRNA gene sequence identity to the type strain of Psychromonas arctica, but less than 97â% 16S rRNA gene sequence similarities to all other species of the genus Psychromonas. DNA-DNA hybridization with Psychromonas arctica DSM 14288T showed low values (21â%, reciprocal 27â%). The main cellular fatty acid of strain M1A1T was summed feature 3 fatty acids (C16â:â1ω7c/C16â:â1ω8c), followed by C16â:â0. Based on phylogenetic, chemotaxonomic, genomic and phenotypic analyses, we propose a novel species of the genus Psychromonas with the name Psychromonas aquatilis sp. nov. and the strain M1A1T (=CIP 111183T=CCM 8710T=LMG 29766T) as type strain.
Assuntos
Gammaproteobacteria/classificação , Filogenia , Água do Mar/microbiologia , Regiões Antárticas , Técnicas de Tipagem Bacteriana , Composição de Bases , Chile , DNA Bacteriano/genética , Ácidos Graxos/química , Gammaproteobacteria/genética , Gammaproteobacteria/isolamento & purificação , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
A group of seven Chilean isolates presumptively belonging to Vibrio tapetis was isolated from diseased fine flounders (Paralichthys adspersus) and red conger eel (Genypterus chilensis) experimentally reared in Quintay (Chile). All isolates were confirmed as members of V. tapetis on the basis of matrix-assisted laser desorption ionization time-of-flight MS, 16S rRNA gene sequencing, DNA-DNA hybridization values and G+C content. The ERIC-PCR and REP-PCR patterns were homogeneous among those isolates recovered from the same host (red conger or fine flounders), but distinct from the type strains V. tapetis subsp. tapetis CECT 4600T and V. tapetis subsp. britannicus CECT 8161T. On the basis of atpA, rpoA, rpoD, recA and pyrH gene sequence similarities (99.7-100â%) and clustering in the phylogenetic trees, the red conger isolates (Q20, Q047, Q48 and Q50) were confirmed as representing V. tapetis subsp. tapetis. However, they differed from V. tapetis subsp. tapetis CECT 4600T in their lipase, alpha quimiotripsin and non-acid phosphatase production. On the other hand, the fine flounder isolates (QL-9T, QL-35 and QL-41) showed rpoD, recA and pyrH gene sequence similarities ranging from 91.6 to 97.7â% with the type strains of the two V. tapetis subspecies (CECT 4600T and CECT 8161T) and consistently clustered together as an independent phylogenetic line within V. tapetis. Moreover, they could be differentiated phenotypically from strains CECT 4600T and CECT 8161T by nine and three different biochemical tests, respectively. In conclusion, the presence of V. tapetis in diseased red conger eel and fine flounder was demonstrated, extending the known host range and geographical location for this pathogen. Furthermore, this study demonstrates that the three isolates from fine flounder represent a novel subdivision within V. tapetis, for which the name V. tapetis subsp. quintayensis subsp. nov. is proposed and with QL-9T (=CECT 8851T=LMG 28759T) as the type strain. Although QL-9T was isolated from kidney of diseased fine flounder specimens, the challenge assays showed that it was non-pathogenic for this species.