RESUMO
Quartzite caves located on table-top mountains (tepuis) in the Guyana Shield, are ancient, remote, and pristine subterranean environments where microbes have evolved peculiar metabolic strategies to thrive in silica-rich, slightly acidic and oligotrophic conditions. In this study, we explored the culturable fraction of the microbiota inhabiting the (ortho)quartzite cave systems in Venezuelan tepui (remote table-top mountains) and we investigated their metabolic and enzymatic activities in relation with silica solubilization and extracellular hydrolytic activities as well as the capacity to produce antimicrobial compounds. Eighty microbial strains were isolated with a range of different enzymatic capabilities. More than half of the isolated strains performed at least three enzymatic activities and four bacterial strains displayed antimicrobial activities. The antimicrobial producers Paraburkholderia bryophila CMB_CA002 and Sphingomonas sp. MEM_CA187, were further analyzed by conducting chemotaxonomy, phylogenomics, and phenomics. While the isolate MEM_CA187 represents a novel species of the genus Sphingomonas, for which the name Sphingomonas imawarii sp. nov. is proposed, P. bryophila CMB_CA002 is affiliated with a few strains of the same species that are antimicrobial producers. Chemical analyses demonstrated that CMB_CA002 produces ditropolonyl sulfide that has a broad range of activity and a possibly novel siderophore. Although the antimicrobial compounds produced by MEM_CA187 could not be identified through HPLC-MS analysis due to the absence of reference compounds, it represents the first soil-associated Sphingomonas strain with the capacity to produce antimicrobials. This work provides first insights into the metabolic potential present in quartzite cave systems pointing out that these environments are a novel and still understudied source of microbial strains with biotechnological potential.
Assuntos
Bactérias , Cavernas , Filogenia , RNA Ribossômico 16S , Cavernas/microbiologia , RNA Ribossômico 16S/genética , Bactérias/classificação , Bactérias/metabolismo , Bactérias/isolamento & purificação , Bactérias/genética , Dióxido de Silício/química , Microbiota , Venezuela , Sphingomonas/metabolismo , Sphingomonas/isolamento & purificação , Sphingomonas/classificação , Sphingomonas/genética , Biotecnologia/métodos , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Microbiologia do Solo , DNA Bacteriano/genéticaRESUMO
Biosynthesis of titanium dioxide nanoparticles (TiO2NPs) by Sphingomonas paucimobilis B34 bacteria was successfully achieved and followed by UV-Vis spectroscopy. The nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and fourier transform infrared spectroscopy (FTIR) techniques. The biosynthesized TiO2NPs were spherical in shape with an average particle size of 15.6 nm. These TiO2NPs were used as nono-catalyst for removing of malachite green (MG) dye (at 103 mol/L) from wastewater solution. As indicated by the results, the biosynthesized TiO2NPs represented a capable approach for MG removal with up to 83 % efficiency. The removal process was found to follow a pseudo-first-order kinetics. Furthermore, the developed TiO2NPs-MG hybrid nanocomposite was efficiently removed from the medium by using Spirulina platensis cyanobacterial biomass after wastewater treatment. S. platensis biomass was able to remove up to 89.43 % of the hybrid nanocomposite by a biosorption process. The resultant water effluent, after TiO2NPs-MG removal, showed no toxicity towards Vigna radiate L. seedlings implying its safety for agriculture purposes. According to the obtained results, S. platensis living biomass could play a dual re-cycling role, as natural biosorbent for removing both nanoparticles and dye (TiO2NPs-MG hybrid nano-composite) from solution after wastewater treatment for healthier environmental management.
Assuntos
Nanocompostos , Nanopartículas , Spirulina , Purificação da Água , Biomassa , Corantes de Rosanilina , Sphingomonas , TitânioRESUMO
BACKGROUND: Manno-oligosaccharides (MOS) is known as a kind of prebiotics. Mannanase plays a key role for the degradation of mannan to produce MOS. In this study, the mannanases of glycoside hydrolase (GH) families 5 Man5HJ14 and GH26 ManAJB13 were employed to prepare MOS from locust bean gum (LBG) and palm kernel cake (PKC). The prebiotic activity and utilization of MOS were assessed in vitro using the probiotic Lactobacillus plantarum strain. RESULTS: Galactomannan from LBG was converted to MOS ranging in size from mannose up to mannoheptose by Man5HJ14 and ManAJB13. Mannoheptose was got from the hydrolysates produced by Man5HJ14, which mannohexaose was obtained from LBG hydrolyzed by ManAJB13. However, the same components of MOS ranging in size from mannose up to mannotetrose were observed between PKC hydrolyzed by the mannanases mentioned above. MOS stability was not affected by high-temperature and high-pressure condition at their natural pH. Based on in vitro growth study, all MOS from LBG and PKC was effective in promoting the growth of L. plantarum CICC 24202, with the strain preferring to use mannose to mannotriose, rather than above mannotetrose. CONCLUSIONS: The effect of mannanases and mannan difference on MOS composition was studied. All of MOS hydrolysates showed the stability in adversity condition and prebiotic activity of L. plantarum, which would have potential application in the biotechnological applications.
Assuntos
Oligossacarídeos/metabolismo , beta-Manosidase/metabolismo , Gomas Vegetais/química , Mananas , Técnicas In Vitro , Estabilidade Enzimática , Sphingomonas , Prebióticos , FermentaçãoRESUMO
Photolyases are proteins that enzymatically repair the UV-induced DNA damage by a protein-DNA electron transfer mechanism. They repair either cyclobutane pyrimidine dimers or pyrimidine (6-4) pyrimidone photoproducts or just (6-4)-photoproducts. In this work, we report the production and partial characterization of a recombinant (6-4)-photolyase (SphPhrB97) from a bacterial psychrotolerant Antarctic isolate identified as Sphingomonas sp. strain UV9. The spectrum analysis and the in silico study of SphPhrB97 suggest that this enzyme has similar features as compared to the (6-4)-photolyase from Agrobacterium tumefaciens (4DJA; PhrB), including the presence of three cofactors: FAD, DMRL (6,7-dimethyl-8-(1'-D-ribityl) lumazine), and an Fe-S cluster. The homology model of SphPhrB97 predicts that the DNA-binding pocket (area and volume) is larger as compared to (6-4)-photolyases from mesophilic microbes. Based on sequence comparison and on the homology model, we propose an electron transfer pathway towards the FAD cofactor involving the residues Trp342, Trp390, Tyr40, Tyr391, and Tyr399. The phylogenetic tree performed using curated and well-characterized prokaryotic (6-4)-photolyases suggests that SphPhrB97 may have an ancient evolutionary origin. The results suggest that SphPhrB97 is a cold-adapted enzyme, ready to cope with the UV irradiation stress found in a hostile environment, such as Antarctica.
Assuntos
Proteínas de Bactérias/química , Desoxirribodipirimidina Fotoliase , Sphingomonas/enzimologia , Regiões Antárticas , Proteínas de Bactérias/genética , Reparo do DNA , Desoxirribodipirimidina Fotoliase/química , Desoxirribodipirimidina Fotoliase/genética , Filogenia , Dímeros de Pirimidina , Proteínas Recombinantes , Sphingomonas/genética , Raios UltravioletaRESUMO
Mining wastes containing appreciable concentrations of silver are considered alternative sources for metal extraction, although these wastes are often refractory due to the presence of manganese oxides. The high cost and/or environmental impact of the hydrometallurgical and pyrometallurgical extraction processes make it necessary to search for biotechnological processes for the solubilization of manganese compounds. This paper describes the characterization of chemoorganotrophic microorganisms indigenous to the tailings of a silver mine located in Coahuila, México, regarding their capability to remove manganese and silver present in these residues by lixiviation. The Bacterial and fungal strains isolated were identified by sequencing the rDNA 16S and ITS-1-ITS-2 genomic regions, respectively; the bacterial strains correspond to isolates of Roseospira sp. and Sphingomonas sp., whereas the fungal strains include isolates of Cladosporium sp. A, Cladosporium sp. B and Penicillium chrysogenum. These fungal strains show an effective capacity to lixiviate manganese and silver from solid mine residue when incubated in 9 k medium; it was found that under these conditions, leaching of metals occurs due to a mixed biotic-abiotic process, which yields manganese and silver leaching efficiencies in the ranges of 58-74% and 40-67%, respectively. The fungal strains grown in the LMM medium and the bacterial strains incubated in the PDB medium caused leaching of manganese with a lower efficiency in the range of 0.17-0.24% and 1.42-1.73%, respectively; under these conditions, silver leaching by fungal and bacterial strains appeared to be reduced (< 0.1%).Through in vitro cultures, it was determined that P. chrysogenum and Sphingomonas sp. showed the highest levels of silver resistance.
Assuntos
Bactérias/metabolismo , Manganês/metabolismo , Prata/metabolismo , Bactérias/efeitos dos fármacos , Biotecnologia/métodos , Tolerância a Medicamentos , Fungos , Resíduos Industriais , Metais Pesados , México , Mineração , Prata/farmacologia , SphingomonasRESUMO
Photolyases are flavoproteins that repair ultraviolet-induced DNA lesions (cyclobutane pyrimidine dimer or CPD, and pyrimidine (6-4) pyrimidone photoproducts or (6-4)-PPs), using blue light as an energy source. These enzymes are substrate specific, meaning that a specific photolyase repairs either a CPD or a (6-4)-PP. In this work, we produced a class II CPD-photolyase (called as PhrSph98) from the Antarctic bacterium Sphingomonas sp. UV9 by recombinant DNA technology and we purified the enzyme using immobilized metal affinity chromatography. By using an immunochemistry assay, with monoclonal antibodies against CPD and (6-4)-PP, we found that PhrSph98 repairs both DNA lesions. The result was confirmed by immunocytochemistry using immortalized non-tumorigenic human keratinocytes. Results from structure prediction, pocket computation, and molecular docking analyses showed that PhrSph98 has the two expected protein domains (light-harvesting antenna and a catalytic domain), a larger catalytic site as compared with photolyases produced by mesophilic organisms, and that both substrates fit the catalytic domain. The results obtained from predicted homology modeling suggest that the electron transfer pathway may occur following this pathway: Y389-W369-W390-F376-W381/FAD. The evolutionary reconstruction of PhrSph98 suggests that this is a missing link that reflects the transition of (6-4)-PP repair into the CPD repair ability for the class II CPD-photolyases. To the best of our knowledge, this is the first report of a naturally occurring bifunctional, CPD and (6-4)-PP, repairing enzyme. KEY POINTS: ⢠We report the first described bifunctional CPD/(6-4)-photoproducts repairing enzyme. The bifunctional enzyme reaches the nuclei of keratinocyte and repairs the UV-induced DNA damage. The enzyme should be a missing link from an evolutionary point of view. The enzyme may have potential uses in the pharmaceutical and cosmetic industries.
Assuntos
Reparo do DNA , Desoxirribodipirimidina Fotoliase/química , Desoxirribodipirimidina Fotoliase/metabolismo , Sphingomonas/enzimologia , Regiões Antárticas , Domínio Catalítico , DNA Recombinante , Desoxirribodipirimidina Fotoliase/genética , Transporte de Elétrons , Enzimas Imobilizadas/metabolismo , Escherichia coli/genética , Células HaCaT , Humanos , Queratinócitos , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Sphingomonas/genéticaRESUMO
Electronic waste (E-Waste) is consumed at high speed in the world. These residues contain metals that increase their price each year, generating new research on the ability of microorganisms to recover the metals from these wastes. Therefore, this work evaluated the biologic lixiviation of Cu, Ag and Au from printed circuit boards (PCB) of mobile phones by three strains of Aspergillus niger, Candida orthopsilosis, Sphingomonas sp. and their respective consortia, in addition to leaching with citric acid. The microorganisms were cultured in mineral media with 0.5 g of PCB, and the treatments with 1M citric acid were added the same amount of PCB. All treatments were incubated for 35 days at room temperature. The results showed that Sphingomonas sp. MXB8 and the consortium of C. orthopsilosis MXL20 and A. niger MXPE6 can increase their dry biomass by 147% and 126%, respectively, in the presence of PCB. In the bioleaching of metals, the inoculation of A. niger MXPE6, the consortium of Sphingomonas sp. MXB8/C. orthopsilosis MXL20 and Sphingomonas sp. MXB8 leached 54%, 44.2% and 35.8% of Ag. The consortium of A. niger MX5 and A. niger MXPE6 showed a leaching of 0.53% of Au. A. niger MX5 leaching 2.8% Cu. Citric acid increased Cu leaching by 280% compared to treatments inoculated with microorganisms. Although further research is required, A. niger MXPE6 and the consortium of Sphingomonas sp. MXB8/C. orthopsilosis MXL20 could be an alternative to recover Ag from PCB of mobile phones.
Assuntos
Telefone Celular , Cobre/metabolismo , Resíduo Eletrônico , Ouro/metabolismo , Consórcios Microbianos , Prata/metabolismo , Aspergillus niger/metabolismo , Candida/metabolismo , Ácido Cítrico/química , Reciclagem/métodos , Sphingomonas/metabolismoRESUMO
Resumen La orquídea Guarianthe skinneri está incluida en la norma NOM-059-ECOL-2010 de México como una especie amenazada. Con el fin de estudiar las BPCV (bacterias promotoras del crecimiento vegetal) en esta orquídea, se recolectaron 10 raíces de diferentes plantas para aislar bacterias asociadas a las raíces, que se analizaron mediante pruebas in vitro como: producción de AIA, fijación de nitrógeno, interacción con el hongo micorrízico Thanatephorus sp. cepa RG26 y solubilización de fosfato. De los 71 aislados bacterianos se caracterizaron 10 cepas mediante secuenciación con el marcador 16s rADN y se identificaron seis cepas: Sphingomonas sp., Sinorhizobium sp., Bacillus sp., Nocardia cerradoensis, Bacillus megaterium y Burkholderia phytofirmans. Se observó que la bacteria Sinorhizobium sp. produjo mayor cantidad de AIA (69.189 µg/ml) y Bacillus sp. presentó mayor reducción de acetileno (10.251 nmol cultivo/96 h). En las interacciones de las bacterias y el hongo RG26 se presentaron cuatro categorías (sumamente positivo, positivo, antagonismo 50-50 e inhibición). En relación a la solubilización de fosfato, la bacteria Burkholderia phytofirmans presentó mayor IS a las 48 y 96 hr con IS de 3.11 y 3.48, respectivamente. Los resultados indican que Bacillus sp. pudiera tener las mejores características para promover el desarrollo de la orquídea G. skinneri mediante la inoculación de semillas y plántulas.
Abstract The Guarianthe skinneri orchid is included in NOM-059-ECOL-2010, Mexico standard as an endangered species. In order to study PGPR (promoting growth plant rhizobacteria) from this orchid, 10 roots were collected from different plants to isolate bacteria associated with the roots, which were analyzed by in vitro tests such as: production of AIA, nitrogen fixation, interaction with the mycorrhizal fungus Thanatephorus sp. strain RG26 and phosphate solubilization. We obtain 71 bacterial isolates, 10 strains of them were characterized by sequencing with the 16d rDNA marker identifying six bacteria: Sphingomonas sp. Sinorhizobium sp. Bacillus sp. Nocardia cerradoensis, Bacillus megaterium and Burkholderia phytofirmans. We observed that the bacterium Sinorhizobium sp. produced a greater amount of AIA (69.189 μg/ml) and Bacillus sp. performed greater acetylene reduction (10.251 nmol cultivo/96h). In the interactions of the bacteria and the fungus RG26, four categories were presented (extremely positive, positive, antagonism 50-50 and inhibition). In relation to the solubilization of phosphate, Burkholderia phytofirmans presented higher IS after 48 and 96 hr with an IS of 3.11 and 3.48, respectively. The results indicate that Bacillus sp. it could have the best characteristics to promote the development of the G. skinneri orchid by inoculating seeds and seedlings. Rev. Biol. Trop. 66(3): 953-968. Epub 2018 September 01.
Assuntos
Sinorhizobium , Sphingomonas/crescimento & desenvolvimento , Orchidaceae , Inoculantes Agrícolas , Fungos , MéxicoRESUMO
In order to study the mechanisms regulating the phenanthrene degradation pathway and the intermediate-metabolite accumulation in strain S. paucimobilis 20006FA, we sequenced the genome and compared the genome-based predictions to experimental proteomic analyses. Physiological studies indicated that the degradation involved the salicylate and protocatechuate pathways, reaching 56.3% after 15 days. Furthermore, the strain degraded other polycyclic aromatic hydrocarbons (PAH) such as anthracene (13.1%), dibenzothiophene (76.3%), and fluoranthene. The intermediate metabolite 1-hydroxy-2-naphthoic acid (HNA) accumulated during phenanthrene catabolism and inhibited both bacterial growth and phenanthrene degradation, but exogenous-HNA addition did not affect further degradation. Genomic analysis predicted 126 putative genes encoding enzymes for all the steps of phenanthrene degradation, which loci could also participate in the metabolism of other PAH. Proteomic analysis identified enzymes involved in 19 of the 23 steps needed for the transformation of phenanthrene to trichloroacetic-acid intermediates that were upregulated in phenanthrene cultures relative to the levels in glucose cultures. Moreover, the protein-induction pattern was temporal, varying between 24 and 96 h during phenanthrene degradation, with most catabolic proteins being overexpressed at 96 h-e. g., the biphenyl dioxygenase and a multispecies (2Fe-2S)-binding protein. These results provided the first clues about regulation of expression of phenanthrene degradative enzymes in strain 20006FA and enabled an elucidation of the metabolic pathway utilized by the bacterium. To our knowledge the present work represents the first investigation of genomic, proteomic, and physiological studies of a PAH-degrading Sphingomonas strain.