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1.
Brief Bioinform ; 24(6)2023 09 22.
Artículo en Inglés | MEDLINE | ID: mdl-37779250

RESUMEN

The microbiota-gut-brain axis denotes a two-way system of interactions between the gut and the brain, comprising three key components: (1) gut microbiota, (2) intermediates and (3) mental ailments. These constituents communicate with one another to induce changes in the host's mood, cognition and demeanor. Knowledge concerning the regulation of the host central nervous system by gut microbiota is fragmented and mostly confined to disorganized or semi-structured unrestricted texts. Such a format hinders the exploration and comprehension of unknown territories or the further advancement of artificial intelligence systems. Hence, we collated crucial information by scrutinizing an extensive body of literature, amalgamated the extant knowledge of the microbiota-gut-brain axis and depicted it in the form of a knowledge graph named MMiKG, which can be visualized on the GraphXR platform and the Neo4j database, correspondingly. By merging various associated resources and deducing prospective connections between gut microbiota and the central nervous system through MMiKG, users can acquire a more comprehensive perception of the pathogenesis of mental disorders and generate novel insights for advancing therapeutic measures. As a free and open-source platform, MMiKG can be accessed at http://yangbiolab.cn:8501/ with no login requirement.


Asunto(s)
Trastornos Mentales , Microbiota , Humanos , Inteligencia Artificial , Reconocimiento de Normas Patrones Automatizadas , Estudios Prospectivos , Encéfalo
2.
Small ; : e2309918, 2023 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-38084467

RESUMEN

Anode materials with high-rate performances and good electrochemical stabilities are urgently required for the grid-scale application of lithium-ion batteries (LIBs). Theoretically, transition metal borides are desirable candidates because of their appropriate working potentials and good conductivities. However, the reported metal borides exhibit poor performances owing to their lack of favorable Li+ storage sites and poor structural stabilities during long-term charging/discharging. In this work, a ternary alkali metal boride, Li1.2 Ni2.5 B2 , which displays a high Li+ storage capacity and remarkable electrochemical stability and an excellent rate performance is studied. In contrast to conventional transition metal borides, the introduction of Li atoms facilitates the formation of 1D Ni/B-based honeycomb channels during synthesis. This Ni/B framework successfully sustains the strain during Li+ intercalation and deintercalation, and thus, the optimized Li1.2 Ni2.5 B2 anode exhibits an excellent cycle stability over 500 charge/discharge cycles. This electrode also exhibits superior reversible capacities of 350, 183, and 80 mA h g-1 at 0.1, 1, and 5 A g-1 , respectively, indicating the considerable potential of the 1D Ni/B framework as a commercially available fast-charging LIB anode.

3.
Immun Ageing ; 20(1): 70, 2023 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-38041117

RESUMEN

Nicotinamide adenine dinucleotide (NAD+), a crucial coenzyme in cellular redox reactions, is closely associated with age-related functional degeneration and metabolic diseases. NAD exerts direct and indirect influences on many crucial cellular functions, including metabolic pathways, DNA repair, chromatin remodeling, cellular senescence, and immune cell functionality. These cellular processes and functions are essential for maintaining tissue and metabolic homeostasis, as well as healthy aging. Causality has been elucidated between a decline in NAD levels and multiple age-related diseases, which has been confirmed by various strategies aimed at increasing NAD levels in the preclinical setting. Ovarian aging is recognized as a natural process characterized by a decline in follicle number and function, resulting in decreased estrogen production and menopause. In this regard, it is necessary to address the many factors involved in this complicated procedure, which could improve fertility in women of advanced maternal age. Concerning the decrease in NAD+ levels as ovarian aging progresses, promising and exciting results are presented for strategies using NAD+ precursors to promote NAD+ biosynthesis, which could substantially improve oocyte quality and alleviate ovarian aging. Hence, to acquire further insights into NAD+ metabolism and biology, this review aims to probe the factors affecting ovarian aging, the characteristics of NAD+ precursors, and the current research status of NAD+ supplementation in ovarian aging. Specifically, by gaining a comprehensive understanding of these aspects, we are optimistic about the prominent progress that will be made in both research and therapy related to ovarian aging.

4.
Wei Sheng Wu Xue Bao ; 54(12): 1462-70, 2014 Dec 04.
Artículo en Zh | MEDLINE | ID: mdl-25876332

RESUMEN

OBJECTIVE: Yunnan hot springs have highly diverseammonia-oxidizing archaea (AOA), which are autotrophic and can fix CO2 using the 3-hydroxypropionate/ 4-hydroxybutyrate (HP/HD) pathway. In this study, we investigated the abundances of prokaryotic 16S rRNA gene and archaeal accA and amoA genes in the sediments of hot springs of Yunnan Province, and analysed the correlations between the above gene abundances and environmental factors. METHODS: We selected the sediments of twenty representative hot springs, and detected the gene abundances by quantitative polymerase chain reaction (qPCR). The principal component analysis (PCA) and the Mantel test in the R software package were performed for the correlations of gene abundance and environmental variables. RESULTS: The bacterial and archaeal 16S rRNA gene abundances were from 6.6 x 10(7) to 4.19 x 10(11) and from 1.27 x 10(6) to 1.51 x 10(11) copies/g sediment, respectively; Archaeal accA and amoA genes were from 8.89 x 10(3) to 6.49 x 10(5) and from 7.64 x 10(3) to 4.36 x 10(5) copies/g sediment, respectively. The results of mantel test showed that accA gene was significantly (R = 0.98, P < 0.001) correlated with amoA gene; Both of them also were correlated significantly with NO2- and NO3 -, but not with pH. CONCLUSION: The abundances of bacterial and archaeal 16S rRNA genes and the ratio between them varied significantly among Yunnan hot springs. The archaealaccA and amoA genes showed significant correlation with each other, validating our previous finding that AOA in terrestrial hot springs might acquire energy from ammonia oxidation coupled with CO2 fixation using the 3-hydroxypropionate/4-hydroxybutyrate pathway.


Asunto(s)
Amoníaco/metabolismo , Archaea/genética , Manantiales de Aguas Termales/microbiología , Nitratos/farmacología , Nitritos/farmacología , Oxidorreductasas/genética , Proteínas Quinasas/genética , Archaea/efectos de los fármacos , China , Oxidación-Reducción
5.
Front Microbiol ; 15: 1292004, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38357350

RESUMEN

Depression is one of the most prevalent mental disorders today. Over the past decade, there has been considerable attention given to the field of gut microbiota associated with depression. A substantial body of research indicates a bidirectional communication pathway between gut microbiota and the brain. In this review, we extensively detail the correlation between gut microbiota, including Lactobacillus acidophilus and Bifidobacterium longum, and metabolites such as short-chain fatty acids (SCFAs) and 5-hydroxytryptamine (5-HT) concerning depression. Furthermore, we delve into the potential health benefits of microbiome-targeted therapies, encompassing probiotics, prebiotics, and synbiotics, in alleviating depression. Lastly, we underscore the importance of employing a constraint-based modeling framework in the era of systems medicine to contextualize metabolomic measurements and integrate multi-omics data. This approach can offer valuable insights into the complex metabolic host-microbiota interactions, enabling personalized recommendations for potential biomarkers, novel drugs, and treatments for depression.

6.
Environ Microbiol ; 15(4): 1160-75, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23126508

RESUMEN

Thousands of hot springs are located in the north-eastern part of the Yunnan-Tibet geothermal zone, which is one of the most active geothermal areas in the world. However, a comprehensive and detailed understanding of microbial diversity in these hot springs is still lacking. In this study, bacterial and archaeal diversities were investigated in 16 hot springs (pH 3.2-8.6; temperature 47-96°C) in Yunnan Province and Tibet, China by using a barcoded 16S rRNA gene-pyrosequencing approach. Aquificae, Proteobacteria, Firmicutes, Deinococcus-Thermus and Bacteroidetes comprised the large portion of the bacterial communities in acidic hot springs. Non-acidic hot springs harboured more and variable bacterial phyla than acidic springs. Desulfurococcales and unclassified Crenarchaeota were the dominated groups in archaeal populations from most of the non-acidic hot springs; whereas, the archaeal community structure in acidic hot springs was simpler and characterized by Sulfolobales and Thermoplasmata. The phylogenetic analyses showed that Aquificae and Crenarchaeota were predominant in the investigated springs and possessed many phylogenetic lineages that have never been detected in other hot springs in the world. Thus findings from this study significantly improve our understanding of microbial diversity in terrestrial hot springs.


Asunto(s)
Archaea/clasificación , Bacterias/clasificación , Variación Genética/genética , Manantiales de Aguas Termales/microbiología , Desequilibrio Ácido-Base , Archaea/genética , Bacterias/genética , China , Crenarchaeota/genética , Genes de ARNr , Manantiales de Aguas Termales/química , Filogenia , Proteobacteria/genética , ARN Ribosómico 16S/genética , Especificidad de la Especie , Sulfolobales/genética , Temperatura , Tibet
7.
Extremophiles ; 17(5): 871-9, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23918087

RESUMEN

It has been suggested that archaea carrying the accA gene, encoding the alpha subunit of the acetyl CoA carboxylase, autotrophically fix CO2 using the 3-hydroxypropionate/4-hydroxybutyrate pathway in low-temperature environments (e.g., soils, oceans). However, little new information has come to light regarding the occurrence of archaeal accA genes in high-temperature ecosystems. In this study, we investigated the abundance and diversity of archaeal accA gene in hot springs in Yunnan Province, China, using DNA- and RNA-based phylogenetic analyses and quantitative polymerase chain reaction. The results showed that archaeal accA genes were present and expressed in the investigated Yunnan hot springs with a wide range of temperatures (66-96 °C) and pH (4.3-9.0). The majority of the amplified archaeal accA gene sequences were affiliated with the ThAOA/HWCG III [thermophilic ammonia-oxidizing archaea (AOA)/hot water crenarchaeotic group III]. The archaeal accA gene abundance was very close to that of AOA amoA gene, encoding the alpha subunit of ammonia monooxygenase. These data suggest that AOA in terrestrial hot springs might acquire energy from ammonia oxidation coupled with CO2 fixation using the 3-hydroxypropionate/4-hydroxybutyrate pathway.


Asunto(s)
Acetil-CoA Carboxilasa/genética , Proteínas Arqueales/genética , Manantiales de Aguas Termales/microbiología , Microbiota , Archaea/clasificación , Archaea/genética , Archaea/aislamiento & purificación , China , Genes Arqueales , Oxidorreductasas/genética , Filogenia
8.
Wei Sheng Wu Xue Bao ; 53(6): 569-76, 2013 Jun 04.
Artículo en Zh | MEDLINE | ID: mdl-24028059

RESUMEN

OBJECTIVE: Crenarchaeota is a major archaeal lineage in terrestrial hot springs and important in biogeochemical cycles of life-essential elements. In this study, we investigated the diversity of Crenarchaeota in hot springs and the surrounding environments in Kamchatka, Russia. In addition, we compared crenarchaeotal community structures in Kamchatka, Russia and Yunnan province, China. METHODS: Crenarchaeal 16S rRNA gene clone libraries were constructed and the sequences and abundances of representational clone were obtained. Phylogenetic analysis was then performed and the community structures in different samples were compared. RESULTS: The high temperature spring Burlyashi Liza (BSL, 89 degrees C) comprised Thermoprotei. The moderate temperature spring TF Vent 2 (TFV, 49 degrees C) harbored unidentified Thermoprotei group, unidentified crenarchaeal group, HWCG-II (hot water crenarchaeotal group II), and Group1. 1b (one thaumarchaeotal subgroup). Most of sequences that obtained from surrounding environments ( <15 degrees C) are closely with the representational clone pJP from a Yellowstone hot spring. Jackknife cluster and Principal coordinates analysis (PCoA) showed that the samples have more similarity in crenarchaeal communities at similar temperatures. CONCLUSION: The diversities of Crenarchaeota in Kamchatka hot springs are somewhat different from those in Yunnan province. Terrestrial hot springs obviously affect the crenarchaeotal communities in surrounding environments. Temperature is the major factor controlling the community structure in terrestrial hot springs.


Asunto(s)
Archaea/aislamiento & purificación , Biodiversidad , Manantiales de Aguas Termales/microbiología , Archaea/clasificación , Archaea/genética , ADN de Archaea/genética , ADN Ribosómico/genética , Ecosistema , Filogenia , ARN Ribosómico 16S/genética , Federación de Rusia
9.
Int J Syst Evol Microbiol ; 62(Pt 10): 2417-2423, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-22140173

RESUMEN

A novel Gram-positive, aerobic, spore-forming, thermophilic actinomycete, designated strain YIM 77521(T), was isolated from a sandy soil sample collected at Rehai National Park, Tengchong, Yunnan province, south-west China. The strain formed branched substrate mycelia and no fragmentation was found. Masses of short, straight or irregular chains of three to eight warty ornamented spores were borne from aerial mycelia. The strain contained meso-diaminopimelic acid in the cell wall and the whole-cell sugars contained mannose, galactose, glucose and ribose. The predominant menaquinones were MK-9(H(4)), MK-9(H(6)) and MK-9(H(8)). The diagnostic polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, hydroxyphosphatidylmonomethylethanolamine and N-acetylglucosamine-containing phospholipids. The major fatty acids were iso-C(16 : 0), C(17 : 0) 10-methyl and C(18 : 0). The DNA G+C content of strain YIM 77521(T) was 73.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain YIM 77521(T) fell within the radiation of the suborder Streptosporangineae and formed a distinct monophyletic lineage adjacent to the family Streptosporangiaceae with a high bootstrap value. On the basis of combined data from the phenotypic and phylogenetic analyses, strain YIM 77521(T) represents a novel genus and species within the family Streptosporangiaceae, for which the name Thermocatellispora tengchongensis gen. nov., sp. nov. is proposed. The type strain is YIM 77521(T) ( = DSM 45615(T)  = CCTCC AA 2011013(T)).


Asunto(s)
Actinomycetales/clasificación , Filogenia , Microbiología del Suelo , Actinomycetales/genética , Actinomycetales/aislamiento & purificación , Técnicas de Tipificación Bacteriana , Composición de Base , Pared Celular/química , China , ADN Bacteriano/genética , Ácidos Grasos/análisis , Datos de Secuencia Molecular , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Esporas Bacterianas , Vitamina K 2/análisis
10.
Antonie Van Leeuwenhoek ; 102(4): 643-51, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22706524

RESUMEN

A Gram-negative and aerobic bacterium, designated YIM 77875(T), was isolated from a geothermal soil sample collected at Rehai National Park, Tengchong, Yunnan Province, south-west China. Bacterial growth occurred from 37 to 65 °C (optimum 50 °C), pH 6.0-8.0 (optimum pH 7.0) and 0-1 % NaCl (w/v). Cells were rod-shaped and colonies were convex, circular, smooth, yellow and non-transparent. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain YIM 77875(T) belongs to the genus Lysobacter. The 16S rRNA gene sequence similarity values between strain YIM 77875(T) and other species of the genus Lysobacter were all below 94.7 %. The polar lipids of strain YIM 77875(T) were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and five unknown phospholipids. The predominant respiratory quinone was Q-8 and the G+C content was 68.8 mol%. Major fatty acids were iso-C(16:0), iso-C(15:0) and iso-C(11:0). On the basis of the morphological and chemotaxonomic characteristics, as well as genotypic data, strain YIM 77875(T) represents a novel species, Lysobacter thermophilus sp. nov., in the genus Lysobacter. The type strain is YIM 77875(T) (CCTCC AB 2012064(T) = KCTC 32020(T)).


Asunto(s)
Lysobacter/clasificación , Lysobacter/aislamiento & purificación , Microbiología del Suelo , Aerobiosis , Técnicas de Tipificación Bacteriana , Composición de Base , China , Análisis por Conglomerados , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Ácidos Grasos , Concentración de Iones de Hidrógeno , Lysobacter/genética , Lysobacter/fisiología , Datos de Secuencia Molecular , Fosfolípidos/análisis , Filogenia , Pigmentos Biológicos/metabolismo , Quinonas/análisis , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Temperatura
11.
Antonie Van Leeuwenhoek ; 102(1): 177-85, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22453518

RESUMEN

Two novel Gram-positive, spore-forming, thermophilic actinomycetes, designated as strain YIM 77501(T) and YIM 77570, were isolated from a sandy soil sample collected at Tengchong National Volcanic Geological Park, Yunnan province, south-west China. Phylogenetic analysis based on the 16S rRNA gene sequences suggested that the two isolates fell within the family Streptosporangiaceae. The strains formed extensively branched substrate and aerial mycelia which carried masses of long, straight or irregular spore chains composed of warty ornamented spores. Cell walls of the two strains contained meso-diaminopimelic acid and glucose, galactose, mannose and ribose were detected as whole-cell sugars. The predominant menaquinones were MK-9(H(4)) and MK-9(H(6)). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, N-acetylglucosamine-containing phospholipids and phosphatidylinositol, phosphatidylinositolmannosides. The major cellular fatty acids were iso-C(16:0) and 10-methyl C(17:0). The DNA G+C content was 74-76 mol%. On the basis of the morphological and chemotaxonomic characteristics as well as the phylogenetic analysis, these strains represents a novel species of a new genus within the family Streptosporangiaceae, for which the name Thermoactinospora rubra gen. nov., sp. nov. is proposed. The type strain of T. rubra is YIM 77501(T) (=DSM 45614(T) = CCTCC AA 2011014(T)).


Asunto(s)
Actinomycetales/clasificación , Actinomycetales/aislamiento & purificación , Actinomycetales/genética , Actinomycetales/fisiología , Composición de Base , Carbohidratos/análisis , Pared Celular/química , China , Análisis por Conglomerados , Citosol/química , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Ácido Diaminopimélico/análisis , Ácidos Grasos/análisis , Datos de Secuencia Molecular , Fosfolípidos/análisis , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Microbiología del Suelo , Esporas Bacterianas/citología , Vitamina K 2/análisis
12.
J Colloid Interface Sci ; 607(Pt 1): 479-487, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34509730

RESUMEN

Controlled synthesis of noble metal nanoparticles with well-defined size and good dispersion on supports has been a long-standing challenge in heterogeneous catalysis. Here we report a facile photo-assisted H2in situ reduction process to synthesize monodispersed Pd nanoparticles with 2-4 nm size on photo-insensitive Sm2O3 rare-earth metal oxide with nanorod morphology. Thanks to the contribution of UV irradiation, the photoelectrons generation in the Sm2O3 support accelerates the H2 reduction of Pd2+ ions into Pd0 and stabilize the growth of very small Pd nanoparticles homogeneously dispersed on the support. The homogeneous distribution of the Pd NPs on the surface of Sm2O3 is most likely attributed to the profuse nucleation sites created by the UV irradiation and the abundance of hydroxyl groups on the support. The hydrogenation of styrene to ethylbenzene was studied as a model reaction. As a result, the UV radiated sample shows an excellent TOF value of 7419 h-1, which is quadruple of the sample without UV irradiation, under the condition of 0.1 MPa H2 at a content of 1.0 wt% Pd. Besides, UV radiated sample shows a negligible performance degradation during the repeated cycling process. This photo-promoted H2 reduction process provides a convenient and straightforward route for assembling materials with novel structures and functions for nanotechnology applications.

13.
Front Microbiol ; 13: 980924, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36160261

RESUMEN

Terrestrial hot springs have been suggested to harbor diverse diazotrophic lineages by using DNA-based nifH gene phylogenetic analysis. However, only a small amount of diazotrophs were ever confirmed to perform nitrogen fixation. In order to explore the compositions of active diazotrophic populations in hot springs, the in situ expression and diversity of nifH and 16S rRNA genes were investigated in the sediments of hot springs (pH 4.3-9.1; temperature 34-84°C) in Tengchong, China, by using high-throughput sequencing. The results showed that active diazotrophs were diverse in the studied Tengchong hot springs. The main active diazotrophs in high-temperature hot springs were affiliated with Aquificae, while those in low-temperature hot springs belonged to Cyanobacteria and Nitrospirae. Such dominance of Aquificae and Nitrospirae of diazotrophs has not been reported in other ecosystems. This suggests that hot springs may harbor unique active diazotrophs in comparison with other type of ecosystems. Furthermore, there were significant differences in the phylogenetic lineages of diazotrophs between hot springs of Tengchong and other regions, indicating that diazotrophs have geographical distribution patterns. Statistical analysis suggests that the expression and distribution of nifH gene were influenced by temperature and concentrations of ammonia and sulfur seem in Tengchong hot springs. These findings avail us to understand element cycling mediated by diazotrophs in hot spring ecosystems.

14.
ACS Appl Mater Interfaces ; 14(16): 18513-18524, 2022 Apr 27.
Artículo en Inglés | MEDLINE | ID: mdl-35437011

RESUMEN

A method for creating genuine nanopores in high area density on monolayer two-dimensional (2D) metallic oxides has been developed. By use of the strong reduction capability of hydroiodic acid, active metal ions, such as FeIII and CoIII, in 2D oxide nanosheets can be reduced to a divalent charge state (2+). The selective removal of FeO2 and CoO2 metal oxide units from the framework can be tuned to produce pores in a range of 1-4 nm. By monitoring of the redox reaction kinetics, the pore area density can be also tuned from ∼0.9 × 104 to ∼3.3 × 105 µm-2. The universality of this method to produce much smaller pores and higher area density than the previously reported ones has been proven in different oxide nanosheets. To demonstrate their potential applications, ultrasmall metal organic framework particles were grown inside the pores of perforated titania oxide nanosheets. The optimized hybrid film showed ∼100% rejection of methylene blue (MB) from the water. Its water permeance reached 4260 L m-2 h-1 bar-1, which is 1-3 orders of that for reported 2D membranes with good MB rejections.

15.
J Hazard Mater ; 439: 129653, 2022 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-35901633

RESUMEN

Electroreducting nitrate (NO3-) into ammonia (NH3), i.e. NO3-RA, can not only relieve NO3- pollution but also produce high value-added NH3. Cu-based species have been taken as a promising catalyst for NO3-RA because of their relatively high Faradaic efficiency (FE), benefiting from the weak side hydrogen evolution reaction (HER). However, their NH3 yield rates are still unsatisfactory due to the multiple electron paths of NO3-RA. Herein, we report a Cu cube with Cu-CuO heterostructured skin, prepared by electrochemically induced reconstruction from a Cu2O cube. This novel Cu-based catalyst presents a mol-level NH3 yield rate of 3.17 mol h-1 g-1 ranking at the top level among non-noble metal catalysts and an ultrahigh FE of 98.7 %. These excellent performances attribute to the Cu-CuO heterostructured skin of Cu cubes, which has favorable energy for the hydrogenation of *NO to *NOH during the NO3-RA process and an unfavorable one for HER. For the NO3- removal of real river water, this novel Cu-based catalyst presents a high NO3- removal rate of 95.5 % after the NO3-RA test for 12 h, resulting in a lower NO3- concentration than the maximum residual amount of NO3- in drinking water limited by WHO and China. This study provides a feasible strategy by the electrochemical reconstruction method to prepare superior Cu-based electrocatalysts with mol-level NO3-RA performances for the purification of nitrate wastewater.


Asunto(s)
Nitratos , Aguas Residuales , Amoníaco , Cobre , Óxidos de Nitrógeno
16.
Extremophiles ; 14(3): 287-96, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20373121

RESUMEN

Diversity of Crenarchaeota was investigated in eight terrestrial hot springs (pH 2.8-7.7; temperature 44-96 degrees C) located in Tengchong, China, using 16S rRNA gene phylogenetic analysis. A total of 826 crenarchaeotal clones were sequenced and a total of 47 operational taxonomic units (OTUs) were identified. Most (93%) of the identified OTUs were closely related (89-99%) to those retrieved from hot springs and other thermal environments. Our data showed that temperature may predominate over pH in affecting crenarchaeotal diversity in Tengchong hot springs. Crenarchaeotal diversity in moderate-temperature (59-77 degrees C) hot springs was the highest, indicating that the moderately hot-temperature springs may provide optimal conditions for speciation of Crenarchaeota.


Asunto(s)
Crenarchaeota/genética , ADN de Archaea/genética , Variación Genética , China , Clonación Molecular , Biblioteca de Genes , Geología , Manantiales de Aguas Termales , Calor , Concentración de Iones de Hidrógeno , Modelos Estadísticos , Filogenia , ARN Ribosómico 16S/genética , Temperatura , Microbiología del Agua
17.
J Colloid Interface Sci ; 578: 89-95, 2020 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-32512399

RESUMEN

To substitute precious metal with non-precious electrocatalysts, that can work efficiently, still remains a great challenge. Herein, we fabricated the series of nitrogen doped carbon (NC) and CoFe-NC core-shell architectures to produce dual-functionality towards oxygen reduction/evolution reactions and ultimately for Zn-air battery. The addition of NC tends to prevent the reduction of Co/Fe nanoparticles during pyrolysis which not only provide improved catalytic sites but also boost the specific surface area, graphitization degree, electron and mass transfer capacity. With distinctive core-shell morphology, the as-synthesized CoFe-NC/NC shows superior OER performance with low overpotential (270 mV) than IrO2 (340 mV) at 10 mA cm-2 and nearly close ORR activity with respect to Pt/C. When fabricated as zinc-air battery application, CoFe-NC/NC shows 58 mW cm-2 higher peak power density than that of air-cathodes made of Pt/C and IrO2. Further, our catalyst shows good durability due to the synergistic effect of Fe/Co and NC shell.

18.
Appl Environ Microbiol ; 74(20): 6417-26, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18676703

RESUMEN

Despite the ubiquity of ammonium in geothermal environments and the thermodynamic favorability of aerobic ammonia oxidation, thermophilic ammonia-oxidizing microorganisms belonging to the crenarchaeota kingdom have only recently been described. In this study, we analyzed microbial mats and surface sediments from 21 hot spring samples (pH 3.4 to 9.0; temperature, 41 to 86 degrees C) from the United States, China, and Russia and obtained 846 putative archaeal ammonia monooxygenase large-subunit (amoA) gene and transcript sequences, representing a total of 41 amoA operational taxonomic units (OTUs) at 2% identity. The amoA gene sequences were highly diverse, yet they clustered within two major clades of archaeal amoA sequences known from water columns, sediments, and soils: clusters A and B. Eighty-four percent (711/846) of the sequences belonged to cluster A, which is typically found in water columns and sediments, whereas 16% (135/846) belonged to cluster B, which is typically found in soils and sediments. Although a few amoA OTUs were present in several geothermal regions, most were specific to a single region. In addition, cluster A amoA genes formed geographic groups, while cluster B sequences did not group geographically. With the exception of only one hot spring, principal-component analysis and UPGMA (unweighted-pair group method using average linkages) based on the UniFrac metric derived from cluster A grouped the springs by location, regardless of temperature or bulk water pH, suggesting that geography may play a role in structuring communities of putative ammonia-oxidizing archaea (AOA). The amoA genes were distinct from those of low-temperature environments; in particular, pair-wise comparisons between hot spring amoA genes and those from sympatric soils showed less than 85% sequence identity, underscoring the distinctness of hot spring archaeal communities from those of the surrounding soil system. Reverse transcription-PCR showed that amoA genes were transcribed in situ in one spring and the transcripts were closely related to the amoA genes amplified from the same spring. Our study demonstrates the global occurrence of putative archaeal amoA genes in a wide variety of terrestrial hot springs and suggests that geography may play an important role in selecting different assemblages of AOA.


Asunto(s)
Archaea/genética , Proteínas Arqueales/genética , ADN de Archaea/genética , ADN de Archaea/aislamiento & purificación , Sedimentos Geológicos/microbiología , Manantiales de Aguas Termales/microbiología , Oxidorreductasas/genética , Archaea/aislamiento & purificación , China , Análisis por Conglomerados , ADN de Archaea/química , Datos de Secuencia Molecular , Filogenia , Polimorfismo Genético , Análisis de Componente Principal , Federación de Rusia , Análisis de Secuencia de ADN , Homología de Secuencia , Estados Unidos
19.
PLoS One ; 8(5): e62901, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23667538

RESUMEN

The Tibetan Plateau in Northwest China hosts a number of hot springs that represent a biodiversity hotspot for thermophiles, yet their diversity and relationship to environmental conditions are poorly explored in these habitats. In this study we investigated microbial diversity and community composition in 13 Tibetan hot springs with a wide range of temperatures (22.1-75°C) and other geochemical conditions by using the 16S rRNA gene pyrosequencing approach. Bacteria (10(8)-10(11) copy/g; 42 bacterial phyla) in Tibetan hot springs were more abundant and far more diverse than Archaea (10(7)-10(10) copy/g; 5 archaeal phyla). The dominant bacterial phyla systematically varied with temperature. Moderate temperatures (75-66°C) favored Aquificae, GAL35, and novel Bacteria, whereas low temperatures (60-22.1°C) selected for Deinococcus-Thermus, Cyanobacteria, and Chloroflexi. The relative abundance of Aquificae was correlated positively with temperature, but the abundances of Deinococcus-Thermus, Cyanobacteria, and Chloroflexi were negatively correlated with temperature. Cyanobacteria and Chloroflexi were abundant in Tibetan hot springs and their abundances were positively correlated at low temperatures (55-43°C) but negatively correlated at moderate temperatures (75-55°C). These correlation patterns suggest a complex physiological relationship between these two phyla. Most archaeal sequences were related to Crenarchaeota with only a few related to Euryarchaeota and Thaumarchaeota. Despite the fact that microbial composition in Tibetan hot springs was strongly shaped by temperature, microbial diversity (richness, evenness and Shannon diversity) was not significantly correlated with temperature change. The results of this study expand our current understanding of microbial ecology in Tibetan hot springs and provide a basis for a global comparison.


Asunto(s)
Manantiales de Aguas Termales/microbiología , Temperatura , Biodiversidad , Chloroflexi/clasificación , Chloroflexi/genética , Cianobacterias/clasificación , Cianobacterias/genética , Sedimentos Geológicos/microbiología , Secuenciación de Nucleótidos de Alto Rendimiento , Modelos Lineales , Microbiología del Suelo , Tibet
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