RESUMEN
Actinobacteria are prokaryotes with a large biotechnological interest due to their ability to produce secondary metabolites, produced by two main biosynthetic gene clusters (BGCs): polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS). Most studies on bioactive products have been carried out on actinobacteria isolated from soil, freshwater or marine habitats, while very few have been focused on halophilic actinobacteria isolated from extreme environments. In this study we have carried out a comparative genomic analysis of the actinobacterial genus Saccharomonospora, which includes species isolated from soils, lake sediments, marine or hypersaline habitats. A total of 19 genome sequences of members of Saccharomonospora were retrieved and analyzed. We compared the 16S rRNA gene-based phylogeny of this genus with evolutionary relationships inferred using a phylogenomic approach obtaining almost identical topologies between both strategies. This method allowed us to unequivocally assign strains into species and to identify some taxonomic relationships that need to be revised. Our study supports a recent speciation event occurring between Saccharomonospora halophila and Saccharomonospora iraqiensis. Concerning the identification of BGCs, a total of 18 different types of BGCs were detected in the analyzed genomes of Saccharomonospora, including PKS, NRPS and hybrid clusters which might be able to synthetize 40 different putative products. In comparison to other genera of the Actinobacteria, members of the genus Saccharomonospora showed a high degree of novelty and diversity of BGCs.
RESUMEN
The draft genome sequence of Saccharomonospora piscinae KCTC 19743T, with a size of 4,897,614 bp, was assembled into 11 scaffolds containing 4,561 open reading frames and a G+C content of 71.0 mol%. Polyketide synthase and nonribosomal peptide synthetase gene clusters, which are responsible for the biosynthesis of several biomolecules, were identified and located in different regions in the genome.
RESUMEN
The genus Salinivibrio belongs to the family Vibrionaceae and includes Gram-stain-negative, motile by a polar flagellum, and facultatively anaerobic curved rods. They are halophilic bacteria commonly found in hypersaline aquatic habitats and salted foods. This genus includes five species and two subspecies. A presumed novel species, strain S35T, was previously isolated from the high-altitude volcanic, alkaline, and saline lake Socompa (Argentinean Andes). In this study we carried out a complete taxonomic characterization of strain S35T, including the 16S rRNA gene sequence and core-genome analysis, the average nucleotide identity (ANIb, ANIm, and orthoANI), and in silico DNA-DNA hybridization (GGDC), as well as the phenotypic and chemotaxonomic characterization. It grew at 3%-20% (w/v) NaCl, pH 6-10, and 10-42 °C, with optimum growth at 7.0%-7.5% (w/v) NaCl, pH 8.0, and 37 °C, respectively. Strain S35T was oxidase- and catalase-positive, able to produce acid from D-glucose and other carbohydrates. Hydrolysis of DNA, methyl red test, and nitrate and nitrite reduction were positive. Its main fatty acids were C16:0, C16:1 ω7c and C16:1 ω6c, and C18:1 ω7c and/or C18:1 ω6c. ANI, GGDC, and core-genome analysis determined that strain S35T constitutes a novel species of the genus Salinivibrio, for which the name Salinivibrio socompensis sp. nov. is proposed. The type strain is S35T (= CECT 9634T = BNM 0535T).
RESUMEN
We carried out a comparative taxonomic study of Salinivibrio proteolyticus and Salinivibrio costicola subsp. vallismortis, as well as of five halophilic strains (IB574, IB872, PR5, PR919 and PR932), isolated from salterns in Spain and Puerto Rico that were closely related to these bacteria. Multilocus sequence analysis of concatenated gyrB, recA, rpoA and rpoD housekeeping genes showed that they constituted a single cluster separate from the other species and subspecies of Salinivibrio. Experimental and in silico DNA-DNA hybridization studies indicated that they are members of the same species, with relatedness of 100-74â% and 97.8-70.0â%, respectively. The average nucleotide identity (ANI) determined for these strains was 99.7-95.6â% for ANIb and 99.7-95.7â% for OrthoANI. However, the ANI values for S. costicolasubsp.vallismortis DSM 8285T with respect to S. costicolasubsp.costicola DSM 11403T and S. costicolasubsp.alcaliphilus DSM 16359T were 78.7 and 78.9â% (ANIb) and 79.4 and 79.4â% (OrthoANI), respectively. The phylogenomic tree based on 1072 concatenated orthologous single-copy core genes confirmed that S. proteolyticus, S. costicolasubsp.vallismortis and the five new isolates constitute a coherent single phylogroup, separated from the other species and subspecies of Salinivibrio. All these data indicate that S. costicolasubsp.vallismortis is a heterotypic synonym of S. proteolyticus and we propose an emended description of this species.
Asunto(s)
Filogenia , Salinidad , Vibrionaceae/clasificación , Microbiología del Agua , Técnicas de Tipificación Bacteriana , ADN Bacteriano/genética , Genes Bacterianos , Tipificación de Secuencias Multilocus , Hibridación de Ácido Nucleico , Puerto Rico , Análisis de Secuencia de ADN , EspañaRESUMEN
The draft genome sequence of Saccharomonospora sp. strain LRS4.154, a moderately halophilic actinobacterium, has been determined. The genome has 4,860,108 bp, a G+C content of 71.0%, and 4,525 open reading frames (ORFs). The clusters of PKS and NRPS genes, responsible for the biosynthesis of a large number of biomolecules, were identified in the genome.
RESUMEN
We combined nucleic acid-based molecular methods, biogeochemical measurements, and physicochemical characteristics to investigate microbial sedimentary ecosystems of Laguna Tebenquiche, Atacama Desert, Chile. Molecular diversity, and biogeochemistry of hypersaline microbial mats, rhizome-associated concretions, and an endoevaporite were compared with: The V4 hypervariable region of the 16S rRNA gene was amplified by pyrosequencing to analyze the total microbial diversity (i.e., bacteria and archaea) in bulk samples, and in addition, in detail on a millimeter scale in one microbial mat and in one evaporite. Archaea were more abundant than bacteria. Euryarchaeota was one of the most abundant phyla in all samples, and particularly dominant (97% of total diversity) in the most lithified ecosystem, the evaporite. Most of the euryarchaeal OTUs could be assigned to the class Halobacteria or anaerobic and methanogenic archaea. Planctomycetes potentially also play a key role in mats and rhizome-associated concretions, notably the aerobic organoheterotroph members of the class Phycisphaerae. In addition to cyanobacteria, members of Chromatiales and possibly the candidate family Chlorotrichaceae contributed to photosynthetic carbon fixation. Other abundant uncultured taxa such as the candidate division MSBL1, the uncultured MBGB, and the phylum Acetothermia potentially play an important metabolic role in these ecosystems. Lithifying microbial mats contained calcium carbonate precipitates, whereas endoevoporites consisted of gypsum, and halite. Biogeochemical measurements revealed that based on depth profiles of O2 and sulfide, metabolic activities were much higher in the non-lithifying mat (peaking in the least lithified systems) than in lithifying mats with the lowest activity in endoevaporites. This trend in decreasing microbial activity reflects the increase in salinity, which may play an important role in the biodiversity.
RESUMEN
We used cultivation-independent methods to investigate the prokaryotic biogeography of the water column in six salt lakes in Inner Mongolia, China, and a salt lake in Argentina. These lakes had different salt compositions and pH values and were at variable geographic distances, on both local and intercontinental scales, which allowed us to explore the microbial community composition within the context of both contemporary environmental conditions and geographic distance. Fourteen 16S rRNA gene clone libraries were constructed, and over 200 16S rRNA gene sequences were obtained. These sequences were used to construct biotic similarity matrices, which were used in combination with environmental similarity matrices and a distance matrix in the Mantel test to discover which factors significantly influenced biotic similarity. We showed that archaeal biogeography was influenced by contemporary environmental factors alone (Na+, CO3(2-), and HCO3(-) ion concentrations; pH; and temperature). Bacterial biogeography was influenced both by contemporary environmental factors (Na+, Mg2+, and HCO3(-) ion concentrations and pH) and by geographic distance.
Asunto(s)
Archaea/clasificación , Archaea/genética , Bacterias/clasificación , Bacterias/genética , Biodiversidad , Microbiología del Agua , Archaea/aislamiento & purificación , Argentina , Bacterias/aislamiento & purificación , China , Análisis por Conglomerados , ADN de Archaea/química , ADN de Archaea/genética , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Genes de ARNr , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Filogenia , ARN de Archaea/genética , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Sales (Química)/análisis , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido Nucleico , Agua/análisisRESUMEN
Three halophilic isolates, strains Halo-G*T, AUS-1 and Naxos II, were compared. Halo-G* was isolated from an evaporitic salt crystal from Baja California, Mexico, whereas AUS-1 and Naxos II were isolated from salt pools in Western Australia and the Greek island of Naxos, respectively. Halo-G*T had been exposed previously to conditions of outer space and survived 2 weeks on the Biopan facility. Chemotaxonomic and molecular comparisons suggested high similarity between the three strains. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the strains clustered with Halorubrum species, showing sequence similarities of 99.2-97.1%. The DNA-DNA hybridization values of strain Halo-G*T and strains AUS-1 and Naxos II are 73 and 75%, respectively, indicating that they constitute a single species. The DNA relatedness between strain Halo-G*T and the type strains of 13 closely related species of the genus Halorubrum ranged from 39 to 2%, suggesting that the three isolates constitute a different genospecies. The G+C content of the DNA of the three strains was 65.5-66.5 mol%. All three strains contained C20C20 derivatives of diethers of phosphatidylglycerol, phosphatidylglyceromethylphosphate and phosphatidylglycerolsulfate, together with a sulfated glycolipid. On the basis of these results, a novel species that includes the three strains is proposed, with the name Halorubrum chaoviator sp. nov. The type strain is strain Halo-G*T (=DSM 19316T=NCIMB 14426T=ATCC BAA-1602T).
Asunto(s)
Sedimentos Geológicos/microbiología , Halorubrum/clasificación , Halorubrum/aislamiento & purificación , Sales (Química) , Composición de Base , California , Análisis por Conglomerados , ADN de Archaea/química , ADN de Archaea/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Genes de ARNr , Glucolípidos/análisis , Grecia , Halorubrum/genética , México , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Fosfolípidos/análisis , Filogenia , ARN de Archaea/genética , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido Nucleico , Australia OccidentalRESUMEN
A Gram-negative, short rod to oval-shaped bacterium (strain MW2a(T)) was isolated from the surface of leaves of the black mangrove Avicennia germinans and subjected to a polyphasic taxonomic study. Strain MW2a(T) was moderately halophilic, growing at NaCl concentrations in the range 0-25 % (w/v) with optimum growth at 5 % (w/v) NaCl. Growth occurred at 12-40 degrees C (optimum, 30-35 degrees C) and at pH 5.0-9.0 (optimum, pH 7.0-8.0). Strain MW2a(T) was strictly aerobic. Phylogenetic analysis based on the 16S rRNA gene showed that the strain belongs to the genus Halomonas. The closest relative was Halomonas marisflavi, with 98.6 % 16S rRNA gene sequence similarity. The DNA G+C content of strain MW2a(T) was 61.5 mol%, which is in the range of values for Halomonas species. DNA-DNA hybridization with H. marisflavi showed a relatedness of 42 % and lower values were obtained with respect to other related Halomonas species. The major fatty acids were C(16 : 0), C(19 : 0) cyclo omega8c, C(18 : 1)omega7c and C(12 : 0) 3-OH. Overall, the phenotypic, genotypic and phylogenetic results presented in this study demonstrate that strain MW2a(T) represents a novel species within the genus Halomonas. The name Halomonas avicenniae sp. nov. is proposed, with strain MW2a(T) (=CECT 7193(T)=CCM 7396(T)) as the type strain.
Asunto(s)
Avicennia/microbiología , Halomonas/clasificación , Halomonas/aislamiento & purificación , Hojas de la Planta/microbiología , Composición de Base , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Microbiología Ambiental , Ácidos Grasos/análisis , Genes de ARNr/genética , Violeta de Genciana , Halomonas/química , Halomonas/fisiología , Concentración de Iones de Hidrógeno , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Fenazinas , Filogenia , Puerto Rico , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido Nucleico , Cloruro de Sodio/metabolismo , TemperaturaRESUMEN
Two sporulating bacterial strains designated CECAP06(T) and CECAP16 were isolated from the rhizosphere of the legume Cicer arietinum in Argentina. Almost-complete 16S rRNA gene sequences identified the isolates as a Paenibacillus species. It was most closely related to Paenibacillus cineris LMG 18439(T) (99.6 % sequence similarity), Paenibacillus favisporus LMG 20987(T) (99.4 % sequence similarity) and Paenibacillus azoreducens DSM 13822(T) (97.7 % sequence similarity). The cells of this novel species were motile, sporulating, rod-shaped, Gram-positive and strictly aerobic. The predominant fatty acids were anteiso-C(15 : 0), C(16 : 0) and iso-C(16 : 0). The DNA G+C content of strains CECAP06(T) and CECAP16 was 51.3 and 50.9 mol%, respectively. Growth was observed from many carbohydrates, but gas production was not observed from glucose. Catalase and oxidase activities were present. The isolates produced beta-galactosidase and hydrolysed aesculin. Gelatinase, caseinase and urease were not produced. The results of DNA-DNA hybridization showed that the strains from this study constitute a novel species of the genus Paenibacillus, for which the name Paenibacillus rhizosphaerae sp. nov. is proposed. The type strain is CECAP06(T) (=LMG 21955(T) = CECT 5831(T)).