RESUMO
There was an error in the proposed genus name in the published article, in that the genus 'Salinivirga' was effectively published while this article was in review. Therefore, the genus 'Salinivirga' should be replaced with 'Saliniramus'. For the convenience of future readers, we have included the complete corrected article below, in which all occurrences of the incorrect genus name have been amended: A halophilic bacterial strain, HL-109T, was isolated from the unicyanobacterial consortium UCC-O, which was obtained from the photosynthetic mat of Hot Lake (Washington, USA). A polyphasic approach using phenotypic, genotypic and chemotaxonomic data was used to classify the strain within the order Rhizobiales. The organism stained Gram-negative and was a moderate thermophile with a growth optimum of 45 °C. It was obligately aerobic, heterotrophic and halophilic, growing in both NaCl and MgSO4 brines. The novel isolate had a polymorphic cellular morphology of short rods with occasional branching, and cells were monotrichous. The major fatty acids detected were C18â:â1, C18â:â0, C16â:â0 and C18â:âcyc. Phylogenetic analysis of the 16S rRNA gene placed the strain in the order Rhizobiales and it shared 94â% identity with the type strain of its nearest relative, Salinarimonas ramus. Morphological, chemotaxonomic and phylogenetic results did not affiliate the novel organism with any of the families in the Rhizobiales; therefore, HL-109T is representative of a new lineage, for which the name Saliniramus fredricksonii gen. nov., sp. nov. is proposed, with the type strain HL-109T (=JCM 31876T=DSM 102886T). In addition, examination of the phylogenetics of strain HL-109T and its nearest relatives, Salinarimonas ramus and Salinarimonasrosea, demonstrates that these halophiles form a clade distinct from the described families of the Rhizobiales. We further propose the establishment of a new family, Salinarimonadaceae fam. nov., to accommodate the genera Saliniramus and Salinarimonas (the type genus of the family).
RESUMO
A halophilic bacterial strain, HL-109T, was isolated from the unicyanobacterial consortium UCC-O, which was obtained from the photosynthetic mat of Hot Lake (Washington, USA). A polyphasic approach using phenotypic, genotypic and chemotaxonomic data was used to classify the strain within the order Rhizobiales. The organism stained Gram-negative and was a moderate thermophile with a growth optimum of 45 °C. It was obligately aerobic, heterotrophic and halophilic, growing in both NaCl and MgSO4 brines. The novel isolate had a polymorphic cellular morphology of short rods with occasional branching, and cells were monotrichous. The major fatty acids detected were C18â:â1, C18â:â0, C16â:â0 and C18â:âcyc. Phylogenetic analysis of the 16S rRNA gene placed the strain in the order Rhizobiales and it shared 94â% identity with the type strain of its nearest relative, Salinarimonas ramus. Morphological, chemotaxonomic and phylogenetic results did not affiliate the novel organism with any of the families in the Rhizobiales; therefore, HL-109T is representative of a new lineage, for which the name Salinivirga fredricksonii gen. nov., sp. nov. is proposed, with the type strain HL-109T (=JCM 31876T=DSM 102886T). In addition, examination of the phylogenetics of strain HL-109T and its nearest relatives, Salinarimonas ramus and Salinarimonasrosea, demonstrates that these halophiles form a clade distinct from the described families of the Rhizobiales. We further propose the establishment of a new family, Salinarimonadaceae fam. nov., to accommodate the genera Salinivirga and Salinarimonas (the type genus of the family).
Assuntos
Alphaproteobacteria/classificação , Cianobactérias/classificação , Lagos/microbiologia , Filogenia , Alphaproteobacteria/genética , Técnicas de Tipagem Bacteriana , Composição de Bases , Cianobactérias/genética , Cianobactérias/isolamento & purificação , DNA Bacteriano/genética , Ácidos Graxos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , WashingtonRESUMO
A thermophilic, filamentous, heterotrophic bacterium, designated strain JAD2(T), a member of an as-yet uncultivated lineage that is present and sometimes abundant in some hot springs worldwide, was isolated from sediment of Great Boiling Spring in Nevada, USA. Cells had a mean diameter of 0.3 µm and length of 4.0 µm, and formed filaments that typically ranged in length from 20 to 200 µm. Filaments were negative for the Gram stain reaction, spores were not formed and motility was not observed. The optimum temperature for growth was 72.5-75 °C, with a range of 67.5-75 °C, and the optimum pH for growth was 6.75, with a range of pH 6.5-7.75. Peptone, tryptone or yeast extract were able to support growth when supplemented with vitamins, but no growth was observed using a variety of defined organic substrates. Strain JAD2(T) was microaerophilic and facultatively anaerobic, with optimal growth at 1% (v/v) O2 and an upper limit of 8% O2. The major cellular fatty acids (>5%) were C(16â:â0), C(19â:â0), C(18â:â0), C(20â:â0) and C(19â:â1). The genomic DNA G+C content was 69.3 mol%. Phylogenetic and phylogenomic analyses using sequences of the 16S rRNA gene and other conserved genes placed JAD2(T) within the phylum Chloroflexi, but not within any existing class in this phylum. These results indicate that strain JAD2(T) is the first cultivated representative of a novel lineage within the phylum Chloroflexi, for which we propose the name Thermoflexus hugenholtzii gen. nov., sp. nov., within Thermoflexia classis nov., Thermoflexales ord. nov. and Thermoflexaceae fam. nov. The type strain of Thermoflexus hugenholtzii is JAD2(T) (â=âJCM 19131(T)â=âCCTCC AB-2014030(T)).
Assuntos
Chloroflexi/classificação , Fontes Termais/microbiologia , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , Chloroflexi/genética , Chloroflexi/isolamento & purificação , DNA Bacteriano/genética , Ácidos Graxos/química , Sedimentos Geológicos/microbiologia , Temperatura Alta , Dados de Sequência Molecular , Nevada , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Several closely related, thermophilic and cellulolytic bacterial strains, designated JKG1(T), JKG2, JKG3, JKG4 and JKG5, were isolated from a cellulolytic enrichment (corn stover) incubated in the water column of Great Boiling Spring, NV. Strain JKG1(T) had cells of diameter 0.7-0.9 µm and length ~2.0 µm that formed non-branched, multicellular filaments reaching >300 µm. Spores were not formed and dense liquid cultures were red. The temperature range for growth was 45-65 °C, with an optimum of 55 °C. The pH range for growth was pH 5.6-9.0, with an optimum of pH 7.5. JKG1(T) grew as an aerobic heterotroph, utilizing glucose, sucrose, xylose, arabinose, cellobiose, CM-cellulose, filter paper, microcrystalline cellulose, xylan, starch, Casamino acids, tryptone, peptone, yeast extract, acetate, citrate, lactate, pyruvate and glycerol as sole carbon sources, and was not observed to photosynthesize. The cells stained Gram-negative. Phylogenetic analysis using 16S rRNA gene sequences placed the new isolates in the class Chloroflexia, but distant from other cultivated members, with the highest sequence identity of 82.5â% to Roseiflexus castenholzii. The major quinone was menaquinone-9; no ubiquinones were detected. The major cellular fatty acids (>5â%) were C18â:â0, anteiso-C17â:â0, iso-C18â:â0, iso-C17â:â0, C16â:â0, iso-C16â:â0 and C17â:â0. The peptidoglycan amino acids were alanine, ornithine, glutamic acid, serine and asparagine. Whole-cell sugars included mannose, rhamnose, glucose, galactose, ribose, arabinose and xylose. Morphological, phylogenetic and chemotaxonomic results suggest that JKG1(T) is representative of a new lineage within the class Chloroflexia, which we propose to designate Kallotenue papyrolyticum gen. nov., sp. nov., Kallotenuaceae fam. nov., Kallotenuales ord. nov. The type strain of Kallotenue papyrolyticum gen. nov., sp. nov. is JKG1(T) (â=âDSM 26889(T)â=âJCM 19132(T)).
Assuntos
Celulose/metabolismo , Chloroflexi/classificação , Fontes Termais/microbiologia , Filogenia , Chloroflexi/genética , Chloroflexi/isolamento & purificação , DNA Bacteriano/genética , Ácidos Graxos/química , Dados de Sequência Molecular , Nevada , Peptidoglicano/química , RNA Ribossômico 16S/genética , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
Culture-independent and enrichment techniques, with an emphasis on members of the Archaea, were used to determine the composition and structure of microbial communities inhabiting microbial mats in the source pools of two geothermal springs near the towns of Arzakan and Jermuk in Armenia. Amplification of small-subunit rRNA genes using "universal" primers followed by pyrosequencing (pyrotags) revealed highly diverse microbial communities in both springs, with >99 % of pyrosequences corresponding to members of the domain Bacteria. The spring in Arzakan was colonized by a photosynthetic mat dominated by Cyanobacteria, in addition to Proteobacteria, Bacteroidetes, Chloroflexi, Spirochaeta and a diversity of other Bacteria. The spring in Jermuk was colonized by phylotypes related to sulfur, iron, and hydrogen chemolithotrophs in the Betaproteobacteria and Epsilonproteobacteria, along with a diversity of other Bacteria. Analysis of near full-length small subunit rRNA genes amplified using Archaea-specific primers showed that both springs are inhabited by a diversity of methanogens, including Methanomicrobiales and Methanosarcinales and relatives of Methanomassiliicoccus luminyensis, close relatives of the ammonia-oxidizing archaeon (AOA) "Candidatus Nitrososphaera gargensis", and the yet-uncultivated Miscellaneous Crenarchaeotal Group and Deep Hydrothermal Vent Crenarchaeota group 1. Methanogenic enrichments confirmed the predicted physiological diversity, revealing methylotrophic, acetoclastic, and hydrogenotrophic methanogenesis at 45 and 55 °C, but not 65 °C. This is one of only a few studies combining cultivation-independent and -dependent approaches to study archaea in moderate-temperature (37-73 °C) terrestrial geothermal environments and suggests important roles for methanogenic archaea and AOA in the carbon and nitrogen biogeochemical cycles in these environments.
Assuntos
Archaea/isolamento & purificação , Fontes Termais/microbiologia , Consórcios Microbianos , Microbiologia da Água , Amônia/metabolismo , Archaea/classificação , Archaea/efeitos dos fármacos , Archaea/genética , Archaea/crescimento & desenvolvimento , Archaea/metabolismo , Armênia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Sequência de Bases , Biodiversidade , DNA Bacteriano/genética , Concentração de Íons de Hidrogênio , Metano/metabolismo , Consórcios Microbianos/genética , Dados de Sequência Molecular , Oxirredução , Fenótipo , Filogenia , RNA Bacteriano/genética , Alinhamento de Sequência , Homologia de Sequência do Ácido Nucleico , Especificidade da Espécie , TemperaturaRESUMO
Increasing anthropogenic inputs of fixed nitrogen are leading to greater eutrophication of aquatic environments, but it is unclear how this impacts the flux and fate of carbon in lacustrine and riverine systems. Here, we present evidence that the form of nitrogen governs the partitioning of carbon among members in a genome-sequenced, model phototrophic biofilm of 20 members. Consumption of NO3 - as the sole nitrogen source unexpectedly resulted in more rapid transfer of carbon to heterotrophs than when NH4 + was also provided, suggesting alterations in the form of carbon exchanged. The form of nitrogen dramatically impacted net community nitrogen, but not carbon, uptake rates. Furthermore, this alteration in nitrogen form caused very large but focused alterations to community structure, strongly impacting the abundance of only two species within the biofilm and modestly impacting a third member species. Our data suggest that nitrogen metabolism may coordinate coupled carbon-nitrogen biogeochemical cycling in benthic biofilms and, potentially, in phototroph-heterotroph consortia more broadly. It further indicates that the form of nitrogen inputs may significantly impact the contribution of these communities to carbon partitioning across the terrestrial-aquatic interface.IMPORTANCE Anthropogenic inputs of nitrogen into aquatic ecosystems, and especially those of agricultural origin, involve a mix of chemical species. Although it is well-known in general that nitrogen eutrophication markedly influences the metabolism of aquatic phototrophic communities, relatively little is known regarding whether the specific chemical form of nitrogen inputs matter. Our data suggest that the nitrogen form alters the rate of nitrogen uptake significantly, whereas corresponding alterations in carbon uptake were minor. However, differences imposed by uptake of divergent nitrogen forms may result in alterations among phototroph-heterotroph interactions that rewire community metabolism. Furthermore, our data hint that availability of other nutrients (i.e., iron) might mediate the linkage between carbon and nitrogen cycling in these communities. Taken together, our data suggest that different nitrogen forms should be examined for divergent impacts on phototrophic communities in fluvial systems and that these anthropogenic nitrogen inputs may significantly differ in their ultimate biogeochemical impacts.
RESUMO
The principles governing acquisition and interspecies exchange of nutrients in microbial communities and how those exchanges impact community productivity are poorly understood. Here, we examine energy and macronutrient acquisition in unicyanobacterial consortia for which species-resolved genome information exists for all members, allowing us to use multi-omic approaches to predict species' abilities to acquire resources and examine expression of resource-acquisition genes during succession. Metabolic reconstruction indicated that a majority of heterotrophic community members lacked the genes required to directly acquire the inorganic nutrients provided in culture medium, suggesting high metabolic interdependency. The sole primary producer in consortium UCC-O, cyanobacterium Phormidium sp. OSCR, displayed declining expression of energy harvest, carbon fixation, and nitrate and sulfate reduction proteins but sharply increasing phosphate transporter expression over 28 days. Most heterotrophic members likewise exhibited signs of phosphorus starvation during succession. Though similar in their responses to phosphorus limitation, heterotrophs displayed species-specific expression of nitrogen acquisition genes. These results suggest niche partitioning around nitrogen sources may structure the community when organisms directly compete for limited phosphate. Such niche complementarity around nitrogen sources may increase community diversity and productivity in phosphate-limited phototrophic communities.
RESUMO
Elucidating nutrient exchange in microbial communities is an important step in understanding the relationships between microbial systems and global biogeochemical cycles, but these communities are complex and the interspecies interactions that occur within them are not well understood. Phototrophic consortia are useful and relevant experimental systems to investigate such interactions as they are not only prevalent in the environment, but some are cultivable in vitro and amenable to controlled scientific experimentation. Nanoscale secondary ion mass spectrometry (NanoSIMS) is a powerful, high spatial resolution tool capable of visualizing the metabolic activities of single cells within a biofilm, but quantitative analysis of the resulting data has typically been a manual process, resulting in a task that is both laborious and susceptible to human error. Here, the authors describe the creation and application of a semiautomated image-processing pipeline that can analyze NanoSIMS-generated data, applied to phototrophic biofilms as an example. The tool employs an image analysis process, which includes both elemental and morphological segmentation, producing a final segmented image that allows for discrimination between autotrophic and heterotrophic biomass, the detection of individual cyanobacterial filaments and heterotrophic cells, the quantification of isotopic incorporation of individual heterotrophic cells, and calculation of relevant population statistics. The authors demonstrate the functionality of the tool by using it to analyze the uptake of (15)N provided as either nitrate or ammonium through the unicyanobacterial consortium UCC-O and imaged via NanoSIMS. The authors found that the degree of (15)N incorporation by individual cells was highly variable when labeled with (15)NH4 (+), but much more even when biofilms were labeled with (15)NO3 (-). In the (15)NH4 (+)-amended biofilms, the heterotrophic distribution of (15)N incorporation was highly skewed, with a large population showing moderate (15)N incorporation and a small number of organisms displaying very high (15)N uptake. The results showed that analysis of NanoSIMS data can be performed in a way that allows for quantitation of the elemental uptake of individual cells, a technique necessary for advancing research into the metabolic networks that exist within biofilms with statistical analyses that are supported by automated, user-friendly processes.
Assuntos
Biofilmes/crescimento & desenvolvimento , Elementos Químicos , Processamento de Imagem Assistida por Computador/métodos , Espectrometria de Massa de Íon Secundário/métodos , Amônia/metabolismo , Automação Laboratorial/métodos , Cianobactérias/metabolismo , Cianobactérias/fisiologia , Nitratos/metabolismoRESUMO
The draft genome of Kallotenue papyrolyticum JKG1(T), a member of the order Kallotenuales, class Chloroflexia, consists of 4,475,263 bp in 4 contigs and encodes 4,010 predicted genes, 49 tRNA-encoding genes, and 3 rRNA operons. The genome is consistent with a heterotrophic lifestyle including catabolism of polysaccharides and amino acids.
RESUMO
Microbial autotroph-heterotroph interactions influence biogeochemical cycles on a global scale, but the diversity and complexity of natural systems and their intractability to in situ manipulation make it challenging to elucidate the principles governing these interactions. The study of assembling phototrophic biofilm communities provides a robust means to identify such interactions and evaluate their contributions to the recruitment and maintenance of phylogenetic and functional diversity over time. To examine primary succession in phototrophic communities, we isolated two unicyanobacterial consortia from the microbial mat in Hot Lake, Washington, characterizing the membership and metabolic function of each consortium. We then analyzed the spatial structures and quantified the community compositions of their assembling biofilms. The consortia retained the same suite of heterotrophic species, identified as abundant members of the mat and assigned to Alphaproteobacteria, Gammaproteobacteria, and Bacteroidetes. Autotroph growth rates dominated early in assembly, yielding to increasing heterotroph growth rates late in succession. The two consortia exhibited similar assembly patterns, with increasing relative abundances of members from Bacteroidetes and Alphaproteobacteria concurrent with decreasing relative abundances of those from Gammaproteobacteria. Despite these similarities at higher taxonomic levels, the relative abundances of individual heterotrophic species were substantially different in the developing consortial biofilms. This suggests that, although similar niches are created by the cyanobacterial metabolisms, the resulting webs of autotroph-heterotroph and heterotroph-heterotroph interactions are specific to each primary producer. The relative simplicity and tractability of the Hot Lake unicyanobacterial consortia make them useful model systems for deciphering interspecies interactions and assembly principles relevant to natural microbial communities.
RESUMO
Great Boiling Spring is a large, circumneutral, geothermal spring in the US Great Basin. Twelve samples were collected from water and four different sediment sites on four different dates. Microbial community composition and diversity were assessed by PCR amplification of a portion of the small subunit rRNA gene using a universal primer set followed by pyrosequencing of the V8 region. Analysis of 164 178 quality-filtered pyrotags clearly distinguished sediment and water microbial communities. Water communities were extremely uneven and dominated by the bacterium Thermocrinis. Sediment microbial communities grouped according to temperature and sampling location, with a strong, negative, linear relationship between temperature and richness at all taxonomic levels. Two sediment locations, Site A (87-80 °C) and Site B (79 °C), were predominantly composed of single phylotypes of the bacterial lineage GAL35 (\[pmacr]=36.1%), Aeropyrum (\[pmacr]=16.6%), the archaeal lineage pSL4 (\[pmacr]=15.9%), the archaeal lineage NAG1 (\[pmacr]=10.6%) and Thermocrinis (\[pmacr]=7.6%). The ammonia-oxidizing archaeon 'Candidatus Nitrosocaldus' was relatively abundant in all sediment samples <82 °C (\[pmacr]=9.51%), delineating the upper temperature limit for chemolithotrophic ammonia oxidation in this spring. This study underscores the distinctness of water and sediment communities in GBS and the importance of temperature in driving microbial diversity, composition and, ultimately, the functioning of biogeochemical cycles.
Assuntos
Archaea/classificação , Bactérias/classificação , Sedimentos Geológicos/microbiologia , Fontes Termais/microbiologia , Microbiologia da Água , Amônia/metabolismo , Archaea/genética , Archaea/isolamento & purificação , Archaea/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Nevada , Filogenia , TemperaturaRESUMO
To characterize high-temperature cellulolytic microbial communities, two lignocellulosic substrates, ammonia fiber-explosion-treated corn stover and aspen shavings, were incubated at average temperatures of 77 and 85°C in the sediment and water column of Great Boiling Spring, Nevada. Comparison of 109,941 quality-filtered 16S rRNA gene pyrosequences (pyrotags) from eight enrichments to 37,057 quality-filtered pyrotags from corresponding natural samples revealed distinct enriched communities dominated by phylotypes related to cellulolytic and hemicellulolytic Thermotoga and Dictyoglomus, cellulolytic and sugar-fermenting Desulfurococcales, and sugar-fermenting and hydrogenotrophic Archaeoglobales. Minor enriched populations included close relatives of hydrogenotrophic Thermodesulfobacteria, the candidate bacterial phylum OP9, and candidate archaeal groups C2 and DHVE3. Enrichment temperature was the major factor influencing community composition, with a negative correlation between temperature and richness, followed by lignocellulosic substrate composition. This study establishes the importance of these groups in the natural degradation of lignocellulose at high temperatures and suggests that a substantial portion of the diversity of thermophiles contributing to consortial cellulolysis may be contained within lineages that have representatives in pure culture.
Assuntos
Genes Arqueais , Fontes Termais/microbiologia , Lignina/química , Consórcios Microbianos/genética , Análise de Sequência de DNA/métodos , Archaeoglobales/genética , Biodiversidade , Desulfurococcales/genética , Temperatura Alta , Nevada , Filogenia , Polissacarídeos/química , RNA Ribossômico 16S/metabolismo , Árvores/microbiologia , Água/química , Microbiologia da Água , Zea mays/microbiologiaRESUMO
Phototrophic microbial mats are compact ecosystems composed of highly interactive organisms in which energy and element cycling take place over millimeter-to-centimeter-scale distances. Although microbial mats are common in hypersaline environments, they have not been extensively characterized in systems dominated by divalent ions. Hot Lake is a meromictic, epsomitic lake that occupies a small, endorheic basin in north-central Washington. The lake harbors a benthic, phototrophic mat that assembles each spring, disassembles each fall, and is subject to greater than tenfold variation in salinity (primarily Mg(2+) and SO(2-) 4) and irradiation over the annual cycle. We examined spatiotemporal variation in the mat community at five time points throughout the annual cycle with respect to prevailing physicochemical parameters by amplicon sequencing of the V4 region of the 16S rRNA gene coupled to near-full-length 16S RNA clone sequences. The composition of these microbial communities was relatively stable over the seasonal cycle and included dominant populations of Cyanobacteria, primarily a group IV cyanobacterium (Leptolyngbya), and Alphaproteobacteria (specifically, members of Rhodobacteraceae and Geminicoccus). Members of Gammaproteobacteria (e.g., Thioalkalivibrio and Halochromatium) and Deltaproteobacteria (e.g., Desulfofustis) that are likely to be involved in sulfur cycling peaked in summer and declined significantly by mid-fall, mirroring larger trends in mat community richness and evenness. Phylogenetic turnover analysis of abundant phylotypes employing environmental metadata suggests that seasonal shifts in light variability exert a dominant influence on the composition of Hot Lake microbial mat communities. The seasonal development and organization of these structured microbial mats provide opportunities for analysis of the temporal and physical dynamics that feed back to community function.