Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.925
Filtrar
Mais filtros










Filtros aplicados

Base de dados
Intervalo de ano de publicação
1.
Artigo em Inglês | MEDLINE | ID: mdl-32067565

RESUMO

Bioremediation is one of the existing techniques applied for treating oil-contaminated soil, which can be improved by the incorporation of low-cost nutritional materials. This study aimed to assess the addition of two low-cost plant residues, sugarcane bagasse (SCB) and leaf litter (LL) of the forest leguminous Mimosa caesalpiniifolia plant (sabiá), either separately or combined, to a contaminated soil from a petroleum refinery area, analyzed after 90 days of treatment. Individually, both amounts of SCB (20 and 40 g kg-1) favored the growth of total heterotrophic bacteria and total fungi, while LL at 20 g kg-1 better stimulated the hydrocarbon-degrading microorganism's activity in the soil. However, no TPH removal was observed under any of these conditions. Higher microbial growth was detected by the application of both plant residues in multicontaminated soil. The maximum TPH removal of 30% was achieved in amended soil with 20 g kg-1 SCB and 20 kg-1 LL. All the experimental conditions revealed changes in the microbial community structure, related to the handling of the soil, with abundance of Alphaproteobacteria. This study demonstrates the effectiveness of the plant residues SCB and LL as low-cost nutritional materials for biodegradation of hydrocarbon in real oil contaminated soil by indigenous populations.


Assuntos
Microbiota , Indústria de Petróleo e Gás , Petróleo/análise , Microbiologia do Solo , Poluentes do Solo/análise , Solo/química , Alphaproteobacteria/crescimento & desenvolvimento , Biodegradação Ambiental , Brasil , Celulose/química , Mimosa/química , Mimosa/microbiologia , Petróleo/metabolismo , Folhas de Planta/química , Folhas de Planta/microbiologia , Saccharum/química , Saccharum/microbiologia , Poluentes do Solo/metabolismo , Resíduos Sólidos
2.
PLoS One ; 15(2): e0228936, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32084150

RESUMO

A total of fifteen potential methyl t-butyl ether (MtBE)-degrading bacterial strains were isolated from contaminated soil. They have been identified as belonging to the genera Bacillus, Pseudomonas, Kocuria, Janibacter, Starkeya, Bosea, Mycolicibacterium, and Rhodovarius. Bacillus aryabhattai R1B, S. novella R8b, and M. mucogenicum R8i were able to grow using MtBE as carbon source, exhibiting different growth behavior and contaminant degradation ability. Their biocontrol ability was tested against various fungal pathogens. Both S. novella R8b and B. aryabhattai were effective in reducing the development of necrotic areas on leaves within 48 hours from Botritys cinerea and Alternaria alternata inoculation. Whereas, M. mucogenicum effectively controlled B. cinerea after 72 hours. Similar results were achieved using Pythium ultimum, in which the application of isolated bacteria increased seed germination. Only M. mucogenicum elicited tomato plants resistance against B. cinerea. This is the first report describing the occurrence of bioremediation and biocontrol activities in M. mucogenicum, B. aryabhattai and S. novella species. The production of maculosin and its antibiotic activity against Rhizoctonia solani has been reported for first time from S. novella. Our results highlight the importance of multidisciplinary approaches to achieve a consistent selection of bacterial strains useful for plant protection and bioremediation purposes.


Assuntos
Bactérias/isolamento & purificação , Biodegradação Ambiental , Éteres Metílicos/toxicidade , Alphaproteobacteria/isolamento & purificação , Alphaproteobacteria/metabolismo , Bacillus/isolamento & purificação , Bacillus/metabolismo , Bactérias/metabolismo , Lycopersicon esculentum/microbiologia , Éteres Metílicos/química , Mycobacteriaceae/isolamento & purificação , Mycobacteriaceae/metabolismo , Doenças das Plantas/microbiologia , Rhizoctonia/crescimento & desenvolvimento , Solo , Microbiologia do Solo
3.
Appl Microbiol Biotechnol ; 104(5): 2067-2077, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31932896

RESUMO

Halohydrin dehalogenases (HHDHs) have attracted much attention due to their ability to synthesize enantiomerically enriched epoxides and ß-haloalcohols. However, most of the HHDHs exhibit low enantioselectivity. Here, a HHDH from the alphaproteobacteria isolate 46_93_T64 (AbHHDH), which shows only poor enantioselectivity in the catalytic resolution of rac-PGE (E = 9.9), has been subjected to protein engineering to enhance its enantioselectivity. Eight mutants (R89K, R89Y, V137I, P178A, N179Q, N179L, F187L, F187A) showed better enantioselectivity than the wild type. The best single mutant N179L (E = 93.0) showed a remarkable 9.4-fold increase in the enantioselectivity. Then, the single mutations were combined to produce the double, triple, quadruple, and quintuple mutants. Among the combinational mutants, the best variant (R89Y/N179L) showed an increased E value of up to 48. The E values of the variants N179L and R89Y/N179L for other epoxides 2-7 were 12.2 to > 200, which showed great improvement compared to 1.2 to 10.5 for the wild type. Using the variant N179L, enantiopure (R)-PGE with > 99% ee could be readily prepared, affording a high yield and a high concentration.


Assuntos
Proteínas de Bactérias/metabolismo , Compostos de Epóxi/química , Compostos de Epóxi/metabolismo , Hidrolases/metabolismo , Alphaproteobacteria/enzimologia , Alphaproteobacteria/genética , Alphaproteobacteria/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Biocatálise , Hidrolases/química , Hidrolases/genética , Hidrolases/isolamento & purificação , Cinética , Modelos Moleculares , Mutação , Engenharia de Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Estereoisomerismo , Especificidade por Substrato
4.
mSphere ; 5(1)2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996418

RESUMO

The vast majority of microbes inhabiting oligotrophic shallow subsurface soil environments have not been isolated or studied under controlled laboratory conditions. In part, the challenges associated with isolating shallow subsurface microbes may persist because microbes in deeper soils are adapted to low nutrient availability or quality. Here, we use high-throughput dilution-to-extinction culturing to isolate shallow subsurface microbes from a conifer forest in Arizona, USA. We hypothesized that the concentration of heterotrophic substrates in microbiological growth medium would affect which microbial taxa were culturable from these soils. To test this, we diluted cells extracted from soil into one of two custom-designed defined growth media that differed by 100-fold in the concentration of amino acids and organic carbon. Across the two media, we isolated a total of 133 pure cultures, all of which were classified as Actinobacteria or Alphaproteobacteria The substrate availability dictated which actinobacterial phylotypes were culturable but had no significant effect on the culturability of Alphaproteobacteria We isolated cultures that were representative of the most abundant phylotype in the soil microbial community (Bradyrhizobium spp.) and representatives of five of the top 10 most abundant Actinobacteria phylotypes, including Nocardioides spp., Mycobacterium spp., and several other phylogenetically divergent lineages. Flow cytometry of nucleic acid-stained cells showed that cultures isolated on low-substrate medium had significantly lower nucleic acid fluorescence than those isolated on high-substrate medium. These results show that dilution-to-extinction is an effective method to isolate abundant soil microbes and that the concentration of substrates in culture medium influences the culturability of specific microbial lineages.IMPORTANCE Isolating environmental microbes and studying their physiology under controlled conditions are essential aspects of understanding their ecology. Subsurface ecosystems are typically nutrient-poor environments that harbor diverse microbial communities-the majority of which are thus far uncultured. In this study, we use modified high-throughput cultivation methods to isolate subsurface soil microbes. We show that a component of whether a microbe is culturable from subsurface soils is the concentration of growth substrates in the culture medium. Our results offer new insight into technical approaches and growth medium design that can be used to access the uncultured diversity of soil microbes.


Assuntos
Actinobacteria/isolamento & purificação , Alphaproteobacteria/isolamento & purificação , Meios de Cultura/química , Microbiologia do Solo , Actinobacteria/crescimento & desenvolvimento , Alphaproteobacteria/crescimento & desenvolvimento , Arizona , Técnicas Bacteriológicas , Centrifugação , Florestas , Filogenia , RNA Ribossômico 16S/genética
5.
Int J Syst Evol Microbiol ; 70(1): 373-379, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31613738

RESUMO

A novel alphaproteobacterium, strain WS11T, was isolated from a deep-sea sediment sample collected from the New Britain Trench. The full-length 16S rRNA gene of strain WS11T had the highest sequence similarity of 97.6 % to Rhizobium subbaraonis JC85T, followed by Mycoplana ramosa DSM 7292T (96.9 %) and Rhizobium azooxidifex Po 20/26T (96.8 %). Phylogenetic analysis of concatenated 16S rRNA, atpD and recA gene sequences showed that strain WS11T was deeply separated from the species within the family Rhizobiaceae. Phylogenomic analysis based on the whole-genome protein sequences showed that strain WS11T formed an independent monophyletic branch in the family Rhizobiaceae, paralleled with the species in the families Brucellaceae and Phyllobacteriaceae within the order Rhizobiales. Cells were Gram-stain-negative, oxidase- and catalase-positive, and aerobic short rods (1.5-2.4×0.9-1.0 µm). Growth was observed at salinities ranging from 0 to 5% (optimum, 1 %), from pH 6.5 to 9 (optimum, pH 7) and at temperatures between 20 and 30 °C (optimum, 28 °C). Strain WS11T was piezotolerant, growing optimally at 0.1 MPa (range 0.1-70 MPa). The main fatty acid was summed feature 8 (C18 : 1 ω7c/C18  : 1 ω 6c). The sole respiratory quinone was ubiquinone-10 (Q-10). The predominant polar lipids were phosphatidylcholine, two unidentified aminophospholipids and an unidentified phospholipid. The genome size was about 4.36 Mbp and the G+C content was 62.3 mol%. The combined genotypic and phenotypic data show that strain WS11T represents a novel species of a novel genus in the family Rhizobiaceae, for which the name Georhizobium profundi gen. nov., sp. nov. is proposed (type strain WS11T=MCCC 1K03498T=KCTC 62439T).


Assuntos
Alphaproteobacteria/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Água do Mar/microbiologia , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Oceano Pacífico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
6.
Int J Syst Evol Microbiol ; 70(1): 327-333, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31592760

RESUMO

An oval- to rod-shaped, motile, Gram-stain-negative, oxidase-positive, catalase-negative, pink-coloured phototrophic bacterium (designated as strain JA968T) was isolated from an estuary near Pata, Gujarat, India. Cells had an intracytoplasmic membrane architecture as lamellae and divided by budding. Strain JA968T had bacteriochlorophyll-a and spirilloxanthin series carotenoids as photosynthetic pigments. The strain exhibited photolithoautotrophic, photoorganoheterotrophic and chemoorganoheterotrophic growth modes and required thiamine as a growth factor. Strain JA968T had C18 : 1ω7c/C18  : 1ω6c as the predominant fatty acid with ubiquinone-10 (Q-10) and menaquinone-10 (MK-10) forming the quinone composition. The genomic DNA G+C content of the strain was 63.5 mol%. Pairwise comparison of 16S rRNA gene sequences showed that strain JA968T was highly similar to Afifella marina DSM 2698T (99.9 %) and Afifella pfennigii DSM 17143T (98.4 %). The average nucleotide identity values were 92 % between strain JA968T and A. marina DSM 2698T, and 78 % between strain JA968T and A. pfennigii DSM 17143T. The digital DNA-DNA hybridization values between strain JA968T and A. marina and A. pfennigii were 49 and 19 %, respectively. The genomic distinction was also supported by differences in phenotypic and chemotaxonomic characteristics. We propose that strain JA968T represents a new species of the genus Afifella with the name Afifella aestuarii sp. nov. The type strain is JA968T (=KCTC 15634T=NBRC 113338T).


Assuntos
Alphaproteobacteria/classificação , Estuários , Filogenia , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Bacterioclorofila A/química , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Índia , Hibridização de Ácido Nucleico , Fotossíntese , Processos Fototróficos , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química , Vitamina K 2/química , Xantofilas/química
7.
Int J Syst Evol Microbiol ; 70(1): 680-686, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31675287

RESUMO

A salt-tolerant, Gram-negative, rod-shaped and yellow-pigmented bacterium, designated strain AY-3RT, was isolated from rhizosphere soil of a desert xerophyte, Haloxylon ammodendron, sampled at Badain Jaran Desert, Alxa region, Inner Mongolia, PR China. Growth of this strain was observed at 20-42 °C (optimum, 28-30 °C), at pH 6.0-9.0 (optimum, pH 6.0-7.0) and at 0-8 % (w/v) NaCl (optimum, 3 %). Results of phylogenetic analysis based on 16S rRNA gene sequences showed that strain AY-3RT was a member of the genus Altererythrobacter, with the highest similarity to Altererythrobacter aerophilus Ery1T (97.6 %), followed by Altererythrobacter xinjiangensis S3-63T (96.9 %). The predominant fatty acids (>10.0 %) were C18 : 1ω7c, C17 : 1ω6c and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The major polar lipids were diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, sphingoglycolipid and one unknown polar lipid. The predominant respiratory quinone was ubiquinone-10. The G+C content of the genomic DNA of strain AY-3RT was 66.3 mol%. On the basis of the data from this polyphasic taxonomic study, strain AY-3RT represents a novel species of the genus Altererythrobacter, named Altererythrobacter rhizovicinus sp. nov. (=MCCC 1K03572T=KCTC 72280T).


Assuntos
Alphaproteobacteria/classificação , Chenopodiaceae/microbiologia , Filogenia , Rizosfera , Microbiologia do Solo , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Fosfolipídeos/química , Pigmentação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
8.
Int J Syst Evol Microbiol ; 70(2): 814-819, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31675288

RESUMO

A Gram-stain-negative, strictly aerobic, rod-shaped bacterium, without flagellum and designated ZYF765T, was isolated from seawater sampled at a depth of 4000 m in the Mariana Trench. Strain ZYF765T grew with 1-15 % (w/v) NaCl (optimum, 4 %), at 16-37 °C (28 °C) and at pH 6.0-10.0 (pH 7.0-8.0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain ZYF765T formed a lineage within the family Hyphomonadaceae, and was distinct from the most closely related species Glycocaulis abyssi, Glycocaulis albus and Glycocaulis alkaliphilus with 16S rRNA gene sequences similarities ranging from 98.42 to 98.63 %. The major respiratory quinone was ubiquinone-10 (Q-10). The polar lipids comprised three unidentified glycolipids, one unidentified aminophospholipid, one unidentified phospholipid and one unidentified aminolipid. The predominant fatty acids (more than 10 % of total fatty acids) were C18 : 1ω7c (46.2 %) and C18 : 0 (14.1 %). The DNA G+C content was 67.7 mol%. On the basis of the results of polyphasic taxonomic analysis, strain ZYF765T is considered to represent a novel species within the genus Glycocaulis, for which the name Glycocaulis profundi sp. nov. is proposed. The type strain is ZYF765T (=JCM 33028T=MCCC 1K03554T).


Assuntos
Alphaproteobacteria/classificação , Filogenia , Água do Mar/microbiologia , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Glicolipídeos/química , Oceano Pacífico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
9.
Int J Syst Evol Microbiol ; 70(2): 779-784, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31682216

RESUMO

A Gram-stain-negative, cocci or short rod-shaped, yellow-pigmented bacterium, designated strain S2-4-2T, was isolated from coastal sediment of Spartina alterniflora in Quanzhou Bay, PR China. Growth was observed at 15-40 °C (optimum, 30 °C) and pH 6.0-8.0 (optimum, pH 7.0). Strain S2-4-2T tolerated 0-10 % NaCl (optimum, 1 %). The 16S rRNA gene of strain S2-4-2T showed highest sequence similarity to Croceicoccus pelagius Ery9T (98.2 %), followed by Croceicoccus naphthovorans PQ-2T, Croceicoccus marinus E4A9T and Croceicoccus mobilis Ery22T (97.6%, 96.3 and 96.3 %, respectively). Phylogenetic analysis based on 16S rRNA gene sequences and phylogenomic analysis based on 92 up-to-date bacterial core gene sets indicated that strain S2-4-2T forms a distinct monophyletic branch affiliated to the genus Croceicoccus. The average nucleotide identity value between strain S2-4-2T and its close relatives were estimated to be 74.8-85.7 %. The respiratory quinone was found to be Q-10. The predominant fatty acids (>10 %) were identified as summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and summed feature 3 (C16 : 1ω7c and C16 : 1ω6c). The polar lipids were identified as phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid and an unidentified phospholipid. The draft genome size of strain S2-4-2T was 3.5 Mb with a genomic G+C content of 63.0 mol%. Based on these results, strain S2-4-2T is concluded to represent a novel species within the genus Croceicoccus, for which the name Croceicoccus sediminis sp. nov. is proposed with the type strain S2-4-2T (=MCCC 1K03706T=KCTC 72146T).


Assuntos
Alphaproteobacteria/classificação , Sedimentos Geológicos/microbiologia , Filogenia , Água do Mar/microbiologia , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Genes Bacterianos , Fosfolipídeos/química , Pigmentação , Poaceae , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
10.
Int J Syst Evol Microbiol ; 70(1): 439-441, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31626588

RESUMO

The present study aimed to examine the taxonomic relationship between two alphaproteobacterial species, Mabikibacter ruber Choi et al. 2017 and Notoacmeibacter marinus Huang et al. 2017. Comparison of the 16S rRNA gene sequences revealed that they shared 99.9 % sequence similarity. Digital DNA-DNA hybridization (dDDH) estimate (79.8 %) and average nucleotide identity (ANI) value (97.8 %) compared between M. ruber YP382-1-A and N. marinus XMTR2A4T, were both greater than the threshold for bacterial species delineation, strongly supporting the hypothesis that they represented a single species. Moreover, M. ruber YP382-1-A and N. marinus XMTR2A4T shared similar physiological and biochemical properties and fatty acid profiles though they displayed distinct colony colours and other minor different properties, including genome size and ability to degrade cellulose, which were presumably due to the presence of a megaplasmid in the genome of M. ruber YP382-1-A. On the basis of the results of genomic analysis, phenotypic and physiological properties, and fatty acid composition, Mabikibacter ruber Choi et al. 2017 is a later heterotypic synonym of Notoacmeibacter marinus Huang et al. 2017 according to the priority of names determined by the date of original publication.


Assuntos
Alphaproteobacteria/classificação , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
11.
Appl Biochem Biotechnol ; 190(2): 540-550, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31396886

RESUMO

Use of nanoparticles as carriers of anticancer drugs is a suitable way for targeted drug delivery and reduction of the side effects. This research focuses on a novel drug carrier for therapeutic goals by the bacterial magnetic nanoparticles (magnetosomes). The unique characteristics of magnetosomes make them ideal nanobiotechnological materials. In this study, magnetic nanoparticles of Alphaproteobacterium MTB-KTN90 were labeled with the radioisotope rhenium-188 and optimized the factors affecting the labeling efficiency. The results showed that the labeling efficiency of magnetosomes with rhenium-188 was more than 96%. The optimum concentration of bacterial nanoparticles was 133 mg/ml and the best time for maximum efficiency labeling was 60 min. The labeling stability showed that the 188Re-nanoparticle complexes have good stability in 29 h. The results of magnetic nanoparticles bacterial cytotoxicity on cancer cells AsPC1 did not show significant toxicity to concentration of 100 µg/µl. Finally, the biogenic magnetic nanoparticles labeled with rhenium-188 can be introduced as a valuable candidate for the targeted therapy of tumor with reducing radiation to surrounding healthy tissues.


Assuntos
Alphaproteobacteria/metabolismo , Magnetismo , Nanopartículas , Radioisótopos/química , Radioterapia/métodos , Rênio/química , Linhagem Celular Tumoral , Humanos
12.
Int J Syst Evol Microbiol ; 70(2): 1250-1258, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31800387

RESUMO

A bacterial strain, designated Sp-1T, was isolated from the heterotrich ciliate Spirostomum yagiui collected from a reservoir located in Ulsan, Republic of Korea. Cells of Sp-1T were Gram stain-negative, rod-shaped, non-spore-forming, non-motile and contained poly-ß-hydroxybutyrate granules. Phylogenetic analyses based on 16S rRNA gene sequences indicated that Sp-1T constituted a distinct phylogenetic lineage within different families in the order Rhizobiales with a pairwise sequence similarity of 95 % to the species of the genus Ochrobactrum: Ochrobactrum anthropi ATCC 49188T and Ochrobactrum cytisi ESC1T (family Brucellaceae). The major cellular fatty acids were C19 : 0 cyclo ω8c (44.4 %) and C16 : 0 (32.1 %). The identified sole isoprenoid quinone was ubiquinone-10 (Q-10). The major polar lipids produced were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminolipid, two unidentified phospholipids and three unidentified lipids. The genome size was about 5.4 Mbp and the DNA G+C content was 68.2 mol%. Sp-1T exhibited the highest average nucleotide identity value of 76.6 % and in silico DNA-DNA hybridization value of 22.1 % with Pseudoxanthobacter soli DSM 19599T (family Xanthobacteraeae). This strain is distinguishable from closely related members of the order Rhizobiales by its differential phenotypic, chemotaxonomic, genomic and phylogenetic characteristics. On the basis of evidence from polyphasic taxonomic analysis, we concluded that Sp-1T represents a novel species in a novel genus within the order Rhizobiales, for which the name Segnochrobactrum spirostomi gen. nov., sp. nov. is proposed. The type strain is Sp-1T (=KCTC 62036T=JCM 32162T). We also describe a novel family, Segnochrobactraceae fam. nov., to encompass the proposed novel genus and species.


Assuntos
Alphaproteobacteria/classificação , Cilióforos/microbiologia , Filogenia , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , República da Coreia , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
13.
Int J Syst Evol Microbiol ; 70(2): 1300-1306, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31804917

RESUMO

A Gram-staining-negative, aerobic, curved rod-shaped and thermophilic bacterial strain, designated YIM 72297T, was isolated from a sediment sample collected from a hot spring in Tengchong county, Yunnan province, south-west China. Growth was observed at pH 5.0-9.0 with an optimum of pH 7.0-7.5, and at 45-60 °C with an optimum of 55 °C. Positive for catalase and oxidase. The 16S rRNA gene sequence comparison indicated that strain YIM 72297T was most closely related to Elioraea tepidiphila DSM 17972T (96.9 %) and showed <91 % sequence similarities to members of the order Rhodospirillales. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YIM 72297T formed a distinct lineage within the genus Elioraea, and revealed that the genus Elioraea formed a novel family-level clade in the order Rhodospirillales. The ANI and the dDNA-DNA hybridization estimate values between strains YIM 72297T and Elioraea tepidiphila DSM 17972T were 70.8 and 20.1 %, respectively. Strain YIM 72297T contained Q-10 as the predominant ubiquinone. The major fatty acids (>5 %) were summed C18 : 0 (35.8 %), summed feature 8 (30.1 %), C16 : 0 (12.6 %), C18 : 1 2OH (5.6 %) and C16 : 0 2OH (5.4 %). The polar lipids consisted of phosphatidylcholine, phosphatidylethanolamine, diphosphosphatidylglycerol and phosphatidylglycerol in addition to two unidentified aminolipids. The DNA G+C content of YIM 72297T was 70.8 mol% (draft genome). On the basis of the polyphasic taxonomic evidence presented in this study, strain YIM 72297T should be classified as representing a novel species of the genus Elioraea, for which the name Elioraea thermophila sp. nov. is proposed, with the type strain YIM 72297T (=CCTCC AB 2017169T=KCTC 62323T). In addition, a novel family, Elioraeaceae fam. nov., is proposed to accommodate the genus Elioraea.


Assuntos
Alphaproteobacteria/classificação , Sedimentos Geológicos/microbiologia , Fontes Termais/microbiologia , Filogenia , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
14.
Arch Microbiol ; 202(4): 815-824, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31844948

RESUMO

Kiloniella laminariae is a true marine bacterium and the first member of the family and order, the Kiloniellaceae and Kiloniellales. K. laminariae LD81T (= DSM 19542T) was isolated from the marine macroalga Saccharina latissima and is a mesophilic, typical marine chemoheterotrophic aerobic bacterium with antifungal activity. Phylogenetic analysis of 16S rRNA gene sequence revealed the similarity of K. laminariae LD81T not only with three validly described species of the genus Kiloniella, but also with undescribed isolates and clone sequences from marine samples in the range of 93.6-96.7%. We report on the analysis of the draft genome of this alphaproteobacterium and describe some selected features. The 4.4 Mb genome has a G + C content of 51.4%, contains 4213 coding sequences including 51 RNA genes as well as 4162 protein-coding genes, and is a part of the Genomic Encyclopaedia of Bacteria and Archaea (GEBA) project. The genome provides insights into a number of metabolic properties, such as carbon and sulfur metabolism, and indicates the potential for denitrification and the biosynthesis of secondary metabolites. Comparative genome analysis was performed with K. laminariae LD81T and the animal-associated species Kiloniella majae M56.1T from a spider crab, Kiloniella spongiae MEBiC09566T from a sponge as well as Kiloniella litopenai P1-1 from a white shrimp, which all inhabit quite different marine habitats. The analysis revealed that the K. laminariae LD81T contains 1397 unique genes, more than twice the amount of the other species. Unique among others is a mixed PKS/NRPS biosynthetic gene cluster with similarity to the biosynthetic gene cluster responsible for the production of syringomycin.


Assuntos
Alphaproteobacteria/genética , Organismos Aquáticos/genética , Genômica , Filogenia , Alphaproteobacteria/classificação , Animais , Organismos Aquáticos/classificação , Organismos Aquáticos/microbiologia , Proteínas de Bactérias/genética , Composição de Bases , Feófitas/microbiologia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Especificidade da Espécie
15.
Proc Natl Acad Sci U S A ; 117(1): 135-140, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31852819

RESUMO

Redox enzymes are capable of catalyzing a vast array of useful reactions, but they require redox partners that donate or accept electrons. Semiconductor nanocrystals provide a mechanism to convert absorbed photon energy into redox equivalents for enzyme catalysis. Here, we describe a system for photochemical carbon-carbon bond formation to make 2-oxoglutarate by coupling CO2 with a succinyl group. Photoexcited electrons from cadmium sulfide nanorods (CdS NRs) transfer to 2-oxoglutarate:ferredoxin oxidoreductase from Magnetococcus marinus MC-1 (MmOGOR), which catalyzes a carbon-carbon bond formation reaction. We thereby decouple MmOGOR from its native role in the reductive tricarboxylic acid cycle and drive it directly with light. We examine the dependence of 2-oxoglutarate formation on a variety of factors and, using ultrafast transient absorption spectroscopy, elucidate the critical role of electron transfer (ET) from CdS NRs to MmOGOR. We find that the efficiency of this ET depends strongly on whether the succinyl CoA (SCoA) cosubstrate is bound at the MmOGOR active site. We hypothesize that the conformational changes due to SCoA binding impact the CdS NR-MmOGOR interaction in a manner that decreases ET efficiency compared to the enzyme with no cosubstrate bound. Our work reveals structural considerations for the nano-bio interfaces involved in light-driven enzyme catalysis and points to the competing factors of enzyme catalysis and ET efficiency that may arise when complex enzyme reactions are driven by artificial light absorbers.


Assuntos
Compostos de Cádmio/química , Dióxido de Carbono/metabolismo , Carbono/química , Luz , Nanotubos/química , Oxirredutases/metabolismo , Fotoquímica/métodos , Sulfetos/química , Acil Coenzima A , Alphaproteobacteria/enzimologia , Catálise , Ciclo do Ácido Cítrico , Transporte de Elétrons , Elétrons , Ferredoxinas/metabolismo , Cetoácidos , Ácidos Cetoglutáricos/metabolismo , Nanopartículas/química , Oxirredução
16.
Nat Commun ; 10(1): 5529, 2019 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-31827088

RESUMO

Phagocytosis is a key eukaryotic feature, conserved from unicellular protists to animals, that enabled eukaryotes to feed on other organisms. It could also be a driving force behind endosymbiosis, a process by which α-proteobacteria and cyanobacteria evolved into mitochondria and plastids, respectively. Here we describe a planctomycete bacterium, 'Candidatus Uab amorphum', which is able to engulf other bacteria and small eukaryotic cells through a phagocytosis-like mechanism. Observations via light and electron microscopy suggest that this bacterium digests prey cells in specific compartments. With the possible exception of a gene encoding an actin-like protein, analysis of the 'Ca. Uab amorphum' genomic sequence does not reveal any genes homologous to eukaryotic phagocytosis genes, suggesting that cell engulfment in this microorganism is probably not homologous to eukaryotic phagocytosis. The discovery of this "phagotrophic" bacterium expands our understanding of the cellular complexity of prokaryotes, and may be relevant to the origin of eukaryotic cells.


Assuntos
Alphaproteobacteria/fisiologia , Fagocitose , Alphaproteobacteria/classificação , Alphaproteobacteria/genética , Alphaproteobacteria/ultraestrutura , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Evolução Biológica , Genoma Bacteriano , Filogenia
17.
Int J Syst Evol Microbiol ; 69(12): 3716-3722, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31592754

RESUMO

A Gram-stain-negative, rod-shaped, non-motile, aerobic, catalase-negative and oxidase-positive bacterium, designated strain Sn-9-2T, was isolated from a cave soil sample collected from Tiandong cave, Guizhou Province, south-west PR China. Growth occurred at 15-40 °C (optimum, 30 °C), at pH 5.0-9.0 (optimum, pH 7.0-8.0) and with 0-1 % NaCl (w/v). The predominant respiration quinone was ubiquinone-10 (Q-10). The major cellular fatty acids were summed feature 8 (C18 : 1ω7c or C18 : 1ω6c; 83.9 %) and C16 : 0 (5.8 %). The major polar lipids were phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphatidylglycerol, three unidentified phospholipids, two unidentified glycolipids, two unidentified polar lipids and one unidentified aminolipid. The DNA G+C content of strain Sn-9-2T was 67.5 mol%. Based on the results of 16S rRNA gene sequence analysis, the nearest phylogenetic neighbours of strain Sn-9-2T (MF958452) were identified as Aquabacter spiritensis (FR733686) DSM 9035T (97.5 %), Xanthobacter autorophicus (jgi.1053054) DSM 432T (97.2 %) and Xanthobacter tagetidis ATCC 700314T RCTF01000015 (96.9 %). The average nucleotide identity values were 78.0, 77.4 and 77.6 % and the digital DNA-DNA hybridization values were 21.8, 22.0 and 18.8 % between strain Sn-9-2T and A. spiritensis DSM 9035T, X. autotrophicus DSM 432T and X. tagetidis DSM 11105T, respectively. The DNA-DNA hybridization data indicated that strain Sn-9-2T represented a novel genomic species. On the basis of the results of phylogenetic analysis, chemotaxonomic data, physiological characteristics and DNA-DNA hybridization data, strain Sn-9-2T should represent a novel species of the genus Aquabacter, for which the name Aquabactercavernae sp. nov. is proposed. The type strain is Sn-9-2T (=KCTC 62308T=CCTCC AB 2018270T).


Assuntos
Alphaproteobacteria/classificação , Cavernas/microbiologia , Filogenia , Microbiologia do Solo , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Glicolipídeos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/química
18.
Environ Microbiol Rep ; 11(6): 855-860, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31659846

RESUMO

In silico and empirical quantification of viruses is paramount for obtaining information on viral populations that have a major impact on biogeochemical cycles. The uncultured Pelagibacter virus vSAG 37-F6 discovered via single-virus genomics is one of the most abundant and cosmopolitan marine viruses; however, little is understood about its temporal variation. Here, we estimated the absolute number of infecting 37-F6 viruses in coastal bacterioplankton from the Mediterranean Sea by using a novel, feasible SYBR Green I chip-based digital PCR (SYBR dPCR) technique, not implemented before for enumerating (uncultured) microbes. Quantitative SYBR dPCR estimated 450-3480 genome copies of virus 37-F6 in cells/mL (i.e. infecting viruses) and a total of ≈10-400 putative infected cells/mL with a potential C release of 0.12-4.9 pg/ml in the analysed samples. Considering that virus 37-F6 is ubiquitous and abundant in all Tara samples, an enormous amount of C could be transformed by this virus through the 'viral shunt'. Thus, this SYBR dPCR technique has enabled the absolute quantification of an ecologically relevant uncultured virus in nature and the estimation of its potential contribution on biogeochemical cycles. Overall, our study also shows that this approach has a broad applicability for quantifying any other target loci in Microbiology and Virology.


Assuntos
Alphaproteobacteria/virologia , Bacteriófagos/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Água do Mar/virologia , Carga Viral/métodos , Vírion/isolamento & purificação , Bacteriófagos/genética , Mar Mediterrâneo , Vírion/genética
19.
Genome Biol Evol ; 11(10): 2941-2953, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31560374

RESUMO

Many of the sequenced bacterial and archaeal genomes encode regions of viral provenance. Yet, not all of these regions encode bona fide viruses. Gene transfer agents (GTAs) are thought to be former viruses that are now maintained in genomes of some bacteria and archaea and are hypothesized to enable exchange of DNA within bacterial populations. In Alphaproteobacteria, genes homologous to the "head-tail" gene cluster that encodes structural components of the Rhodobacter capsulatus GTA (RcGTA) are found in many taxa, even if they are only distantly related to Rhodobacter capsulatus. Yet, in most genomes available in GenBank RcGTA-like genes have annotations of typical viral proteins, and therefore are not easily distinguished from their viral homologs without additional analyses. Here, we report a "support vector machine" classifier that quickly and accurately distinguishes RcGTA-like genes from their viral homologs by capturing the differences in the amino acid composition of the encoded proteins. Our open-source classifier is implemented in Python and can be used to scan homologs of the RcGTA genes in newly sequenced genomes. The classifier can also be trained to identify other types of GTAs, or even to detect other elements of viral ancestry. Using the classifier trained on a manually curated set of homologous viruses and GTAs, we detected RcGTA-like "head-tail" gene clusters in 57.5% of the 1,423 examined alphaproteobacterial genomes. We also demonstrated that more than half of the in silico prophage predictions are instead likely to be GTAs, suggesting that in many alphaproteobacterial genomes the RcGTA-like elements remain unrecognized.


Assuntos
Alphaproteobacteria/genética , Prófagos/genética , Máquina de Vetores de Suporte , Alphaproteobacteria/classificação , Genes Bacterianos , Genes Virais , Genoma Bacteriano
20.
J Microbiol ; 57(11): 976-981, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31555990

RESUMO

A novel, Gram-stain-negative marine bacterium, designated GH2-6T, was isolated from a rhizosphere mudflat of a halophyte (Carex scabrifolia) collected in Gangwha Island, the Republic of Korea. The cells of the organism were strictly aerobic, oxidase- and catalase-positive, non-flagellated rods. Growth occurred at 20-45°C, pH 5-10, and 0.5-9 (w/v) NaCl. The requirement of Na+ for growth (0.5-3%) was observed. The major respiratory quinone was Q-10. The major polar lipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, an aminolipid and a glycolipid. The predominant fatty acids were C18:1ω7c, C18:0, C16:0, C19:0 cyclo ω8c, C18:1ω7c 11-methyl and summed feature 2 (C14:0 3-OH and/or C16:1 iso I). The genome size was 4.45 Mb and the G+C content of the genomic DNA was 61.9 mol%. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain GH2-6T belonged to genus Martelella and formed a tight cluster with M. radicis BM5-7T and M. endophytica YC6887T. Levels of 16S rRNA gene sequence similarity between the novel isolate and members of the genus were 99.3-95.5%, but strain GH2-6T possessed an extended loop (49 nucleotides in length) between positions 187 and 213 of the 16S rRNA gene sequence (E. coli numbering). DDH values in vitro between the novel isolate and the closest relatives were 23.2±12.8-46.3±5.2%. On the basis of polyphasic data presented in this study, the type strain GH2-6T (= KACC 19403T = KCTC 62125T = NBRC 113212T) represents a novel species of the genus Martelella for which the name Martelella lutilitoris sp. nov. is proposed.


Assuntos
Alphaproteobacteria/classificação , Alphaproteobacteria/isolamento & purificação , Sedimentos Geológicos/microbiologia , Filogenia , Rizosfera , Água do Mar/microbiologia , Alphaproteobacteria/genética , Alphaproteobacteria/fisiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Escherichia coli/genética , Ácidos Graxos/química , Glicolipídeos/química , Ilhas , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , República da Coreia , Plantas Tolerantes a Sal , Análise de Sequência de DNA , Ubiquinona/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA