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1.
Ren Fail ; 46(1): 2337287, 2024 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38627212

RESUMEN

OBJECTIVE: This study explored the molecular mechanisms by which dexmedetomidine (Dex) alleviates cisplatin (CP)-induced acute kidney injury (AKI) in rats. METHODS: CP-induced AKI models were established, and Dex was intraperitoneally injected at different concentrations into rats in the model groups. Subsequently, rats were assigned to the control, CP, CP + Dex 10 µg/kg, and CP + Dex 25 µg/kg groups. After weighing the kidneys of the rats, the kidney arterial resistive index was calculated, and CP-induced AKI was evaluated. In addition, four serum biochemical indices were measured: histopathological damage in rat kidneys was detected; levels of inflammatory factors, interleukin (IL)-1ß, IL-18, IL-6, and tumor necrosis factor alpha, in kidney tissue homogenate of rats were assessed through enzyme-linked immunosorbent assay (ELISA); and levels of NLRP-3, caspase-1, cleaved caspase-1, gasdermin D (GSDMD), and GSDMD-N in kidney tissues of rats were determined via western blotting. RESULTS: Dex treatment reduced nephromegaly and serum clinical marker upregulation caused by CP-induced AKI. In addition, hematoxylin and eosin staining revealed that Dex treatment relieved CP-induced kidney tissue injury in AKI rats. ELISA analyses demonstrated that Dex treatment reduced the upregulated levels of proinflammatory cytokines in the kidney tissue of AKI rats induced by CP, thereby alleviating kidney tissue injury. Western blotting indicated that Dex alleviated CP-induced AKI by inhibiting pyroptosis mediated by NLRP-3 and caspase-1. CONCLUSION: Dex protected rats from CP-induced AKI, and the mechanism may be related to NLRP-3/Caspase-1-mediated pyroptosis.


Asunto(s)
Lesión Renal Aguda , Dexmedetomidina , Ratas , Animales , Dexmedetomidina/efectos adversos , Cisplatino/toxicidad , Lesión Renal Aguda/inducido químicamente , Lesión Renal Aguda/prevención & control , Lesión Renal Aguda/patología , Riñón/patología , Interleucina-1beta , Caspasas/efectos adversos
2.
J Neuroinflammation ; 20(1): 203, 2023 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-37674228

RESUMEN

Astrocytes contribute to chronic neuroinflammation in a variety of neurodegenerative diseases, including Parkinson's disease (PD), the most common movement disorder. However, the precise role of astrocytes in neuroinflammation remains incompletely understood. Herein, we show that regulator of G-protein signaling 5 (RGS5) promotes neurodegenerative process through augmenting astrocytic tumor necrosis factor receptor (TNFR) signaling. We found that selective ablation of Rgs5 in astrocytes caused an inhibition in the production of cytokines resulting in mitigated neuroinflammatory response and neuronal survival in animal models of PD, whereas overexpression of Rgs5 had the opposite effects. Mechanistically, RGS5 switched astrocytes from neuroprotective to pro-inflammatory property via binding to the receptor TNFR2. RGS5 also augmented TNFR signaling-mediated pro-inflammatory response by interacting with the receptor TNFR1. Moreover, interrupting RGS5/TNFR interaction by either RGS5 aa 1-108 or small molecular compounds feshurin and butein, suppressed astrocytic cytokine production. We showed that the transcription of astrocytic RGS5 was controlled by transcription factor early B cell factor 1 whose expression was reciprocally influenced by RGS5-modulated TNF signaling. Thus, our study indicates that beyond its traditional role in G-protein coupled receptor signaling, astrocytic RGS5 is a key modulator of TNF signaling circuit with resultant activation of astrocytes thereby contributing to chronic neuroinflammation. Blockade of the astrocytic RGS5/TNFR interaction is a potential therapeutic strategy for neuroinflammation-associated neurodegenerative diseases.


Asunto(s)
Enfermedades Neuroinflamatorias , Proteínas RGS , Animales , Astrocitos , Transducción de Señal , Proteínas RGS/genética , Inflamación
3.
Angew Chem Int Ed Engl ; 62(31): e202304510, 2023 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-37278913

RESUMEN

High-entropy alloy nanoparticles (HEA NPs) have aroused great interest globally with their unique electrochemical, catalytic, and mechanical properties, as well as diverse activity and multielement tunability for multi-step reactions. Herein, a facile low-temperature synthesis method at atmospheric pressure is employed to synthesize Pd-enriched-HEA-core and Pt-enriched-HEA-shell NPs with a single phase of face-centred cubic structure. Interestingly, the lattice of both Pd-enriched-HEA-core and Pt-enriched-HEA-shell enlarge during the formation process of HEA, with tensile strains included in the core and shell of HEA. The as-obtained PdAgSn/PtBi HEA NPs show excellent electrocatalytic activity and durability for methanol oxidation reaction (MOR) and ethanol oxidation reaction (EOR). The specific (mass) activity of PdAgSn/PtBi HEA NPs for MOR is 4.7 mA cm-2 (2874 mA mg(Pd+Pt) -1 ), about 1.7 (5.9) and 1.5 (4.8) times higher than that of commercial Pd/C and Pt/C catalysts, respectively. Additional to high-entropy effect, Pt sites and Pd sites on the interface of the HEA act synergistically to facilitate the multi-step process towards EOR. This study offers a promising way to find a feasible route for scalable HEA manufacturing with promising applications.

4.
J Org Chem ; 85(14): 9301-9312, 2020 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-32614579

RESUMEN

A palladium-catalyzed, photochemical tandem cyclization/dicarbofunctionalization of unactivated alkyl halides containing an alkene moiety offers an appealing route to produce five- or six-membered rings in a redox-neutral fashion. Multisubstituted carbo- and heterocyclic compounds were prepared through the formation of new C-B or C-O bonds, which provides a convenient synthetic route for further transformations. This protocol is characterized by the reaction of alkene regio- and stereoselectivities, good functional group compatibility, wide substrate scope, and mild reaction conditions.

5.
Zhongguo Zhong Yao Za Zhi ; 45(8): 1879-1886, 2020 Apr.
Artículo en Zh | MEDLINE | ID: mdl-32489073

RESUMEN

The root of Angelica sinensis is known throughout Asia for its traditional efficacy in invigorating and promoting blood circulation. The wild germplasm resources of A. sinensis was in short supply, and most of the commercial medicinal materials come from cultivation. To obtain the differences in the transcriptional levels of wild and cultivated of A. sinensis, the full-length transcriptome of A. sinensis was analyzed using PacBio SMRT three-generation high-throughput sequencing technology. Using the high-throughput sequencing platform Illumina HiSeq X Ten PE150, a root transcriptome dataset of wild and cultivated A.sinensis was obtained. The transcriptome sequencing analyses obtained 16.5 Gb database in wild and cultivated A.sinensis, after assembly steps, we obtain 113 906 transcript sequences(insfroms) with an average length of 1 466 nt. BLAST analysis indicated that 109 113(accounting for 95.79% of the total insfroms), 93 276(81.89%),60 638(53.24%),48 928(42.95%),42 876(37.64%)isofroms were successfully annotated in the NR, Swiss-port, GO, KO and KOG databases, respectively. The annotation information can be classified into three categories of biological processes, cellular components and molecular functions of GO classification, involving 128 KEGG standard metabolic pathways. Analysis of 25 463 differential insfroms, 15 090 higher expression in wild A. sinensis, and 10 373 higher in cultivated A. sinensis. In the enrichment analysis of GO and KEGG, differential insfroms were concentrated on the pathway of plant-pathogen interaction, MAPK signaling pathway-plant and plant hormone signal transduction. In this study, high-throughput sequencing was used to obtain the full-length transcription information of A. sinensis, and the overall characteristics of A. sinensis genetic information were clarified. By comparing the differential expression of wild and cultivated A. sinensis at the genetic level, it provides basic information for further screening and breeding of A. sinensis germplasm resources, resistance research and secondary metabolic pathway analysis.


Asunto(s)
Angelica sinensis , Transcriptoma , Asia , Análisis de Datos , Perfilación de la Expresión Génica , Secuenciación de Nucleótidos de Alto Rendimiento , Anotación de Secuencia Molecular
6.
J Am Chem Soc ; 141(35): 13914-13922, 2019 09 04.
Artículo en Inglés | MEDLINE | ID: mdl-31394035

RESUMEN

Multicomponent reactions are fundamentally different from two-component reactions, as multicomponent reactions can enable the efficient and step-economical construction of complex molecular scaffolds from simple precursors. Here, an unprecedented three-component direct C-H addition was achieved in the challenging meta-selective fashion. Fluoroalkyl halides and a wide range of alkenes, including vinylarenes, unactivated alkenes, and internal alkenes, were employed as the coupling partners of arenes in this strategy. The detailed mechanism presented is supported by kinetic isotope studies, radical clock experiments, and density functional theory calculations. Moreover, this strategy provided access to various fluoride-containing bioactive 1,1-diarylalkanes and other challenging synthetically potential products.

7.
J Org Chem ; 83(21): 13296-13307, 2018 11 02.
Artículo en Inglés | MEDLINE | ID: mdl-30354120

RESUMEN

A palladium-catalyzed process to construct oxazoles and oxazolines with broad functional-group tolerance has been developed, and the method introduces difluoromethyl groups into heterocycles in a one-pot fashion. This system uses a carbonyl oxygen as the acceptor for the addition of a vinylpalladium intermediate to achieve the cyclization. Oxazoline derivatives are generated as the Z-isomer with high stereoselectivity. Additionally, we validated the tentative mechanism of this reaction.

8.
J Org Chem ; 83(23): 14626-14636, 2018 12 07.
Artículo en Inglés | MEDLINE | ID: mdl-30451495

RESUMEN

Alkynes difunctionalization is a powerful strategy in organic synthesis that provides a convenient synthetic entry for internal alkenes. The main challenge in this field was considered to be the geometry control of the newly formed double bond (thermodynamically controlled or kinetically controlled). Herein, we report a novel procedure (through the cyclic compounds broken) to completely control the regioselectivity of olefins. The products, difluoroalkyl unsaturated ß-amino acid derivatives, have potential applications in some important pharmaceuticals on account of the special nature of fluorine atoms.

9.
Zhongguo Zhong Yao Za Zhi ; 42(19): 3696-3702, 2017 Oct.
Artículo en Zh | MEDLINE | ID: mdl-29235281

RESUMEN

Oral film is a new type of oral preparation. Due to portability, simple preparation process and good clinical compliance, oral films have become the focus of novel drug delivery system in recent years. Meanwhile, oral films have been gradually used in the development of Chinese medicine preparations. According to the application and approval situation of different types of oral films both at home and abroad in recent years, their research and development status was analyzed, including the basic concept, formulation, manufacturing process and quality control, as well as related progress and development prospects of oral films applied in traditional Chinese medicine. Some suggestions on the technical evaluation of oral films were put forward by considering specific requirements from regulatory agencies. This paper could provide some references for the development and evaluation of oral films. Due to the complexity of the drug substances and the particularity of the drug product, the development and application of oral films in traditional Chinese medicine are still faced with opportunity and challenges.


Asunto(s)
Sistemas de Liberación de Medicamentos , Preparaciones Farmacéuticas , Administración Oral , Composición de Medicamentos , Medicina Tradicional China , Control de Calidad
10.
J Org Chem ; 81(1): 66-76, 2016 Jan 04.
Artículo en Inglés | MEDLINE | ID: mdl-26642246

RESUMEN

An iodine-promoted one-pot radical cyclization reaction of 1,6-enynes with sulfonyl hydrazides to provide five-membered and hexatomic ring sulfonylated products under the same conditions is established. This reaction proceeded smoothly in water and gave the corresponding products by using I2/TBHP instead of expensive and toxic catalysts with C-S and C-I bond formed in one step. This method also allowed easy access to significant functional sulfones for potential applications in medicinal and organic chemistry.

11.
Anal Bioanal Chem ; 407(13): 3545-54, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25732092

RESUMEN

An in-line matrix cleanup method was used for the simultaneous extraction of 15 sulfonamides and two metabolites from manure samples. The ultrasound/microwave-assisted extraction (UMAE) combined with solid-liquid-solid dispersive extraction (SLSDE) procedure provides a simple sample preparation approach for the processing of manure samples, in which the extraction and cleanup are integrated into one step. Ultrasonic irradiation power, extraction temperature, extraction time, and extraction solvent, which could influence the UMAE efficiency, were investigated. C18 was used as the adsorbent to reduce the effects of interfering components during the extraction procedure. The extracts were concentrated, and the analytes were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) without any further cleanup. The isotopically labeled compounds sulfamethoxazole-d 4, sulfamethazine-d 4, sulfamonomethoxine-d 4, and sulfadimethoxine-d 6 were selected as internal standards to minimize the matrix effect in this method. The recoveries of the antibiotics tested ranged from 71 to 118 % at the three spiking levels examined (20, 200, and 500 µg · kg(-1)). The limits of detections were 1.2-3.6 µg · kg(-1) and the limits of quantification were 4.0-12.3 µg · kg(-1) for the sulfonamides and their metabolites. The applicability of the method was demonstrated by analyzing 30 commercial manure samples. The results indicated that UMAE-SLSDE combined with LC-MS/MS is a simple, rapid, and environmentally friendly method for the analysis of sulfonamides and their metabolites in manure, and it could provide the basis for a risk assessment of the antibiotics in agricultural environments.


Asunto(s)
Fraccionamiento Químico/métodos , Cromatografía Liquida/métodos , Estiércol/análisis , Espectrometría de Masas/métodos , Sonicación/métodos , Sulfonamidas/análisis , Extracción Líquido-Líquido/métodos , Microondas , Dosis de Radiación , Extracción en Fase Sólida/métodos , Sulfonamidas/química , Sulfonamidas/efectos de la radiación , Ondas Ultrasónicas
12.
Tumour Biol ; 35(12): 11701-9, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25293518

RESUMEN

Epidermal growth factor receptor (EGFR) inhibitor treatment is a strategy for cancer therapy. However, innate and acquired resistance is a major obstacle of the efficacy. Autophagy is a self-digesting process in cells, which is considered to be associated with anti-cancer drug resistance. The activation of EGFR can regulate autophagy through multiple signal pathways. EGFR inhibitors can induce autophagy, but the specific function of the induction of autophagy by EGFR inhibitors remains biphasic. On the one hand, autophagy induced by EGFR inhibitors acts as a cytoprotective response in cancer cells, and autophagy inhibitors can enhance the cytotoxic effects of EGFR inhibitors. On the other hand, a high level of autophagy after treatment of EGFR inhibitors can also result in autophagic cell death lacking features of apoptosis, and the combination of EGFR inhibitors with an autophagy inducer might be beneficial. Thus, autophagy regulation represents a promising approach for improving the efficacy of EGFR inhibitors in the treatment of cancer patients.


Asunto(s)
Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Autofagia/efectos de los fármacos , Receptores ErbB/antagonistas & inhibidores , Neoplasias/tratamiento farmacológico , Animales , Receptores ErbB/metabolismo , Humanos , Terapia Molecular Dirigida , Neoplasias/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico
13.
Chemistry ; 20(22): 6745-51, 2014 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-24771707

RESUMEN

A straightforward method for the synthesis of highly functionalized vinylarenes through palladium-catalyzed, norbornene-mediated C-H activation/carbene migratory insertion is described. Extension to a one-pot procedure is also developed. Furthermore, this method can also be used to generate polysubstituted bicyclic molecules. The reaction proceeds under mild conditions to give the products in satisfactory yields using readily available starting materials. This is a Catellani-Lautens reaction that incorporates different types of coupling partners. Additionally, this reaction is the first to demonstrate the possibility of combining Pd-catalyzed insertion of diazo compounds and Pd-catalyzed C-H activation.

14.
Chemistry ; 20(49): 16093-6, 2014 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-25339137

RESUMEN

Without extra addition of sulfinate salt, allylic sulfones were synthesized by palladium-catalyzed cross-coupling of aryl iodide with N-tosylhydrazone. In this transformation, not only the diazo compound but also the sulfinate salt, which were both generated in situ from base-mediated decomposition of the N-tosylhydrazone, was used as nucleophilic partner.


Asunto(s)
Compuestos Alílicos/síntesis química , Hidrazonas/química , Paladio/química , Sulfonas/síntesis química , Compuestos de Tosilo/química , Compuestos Alílicos/química , Catálisis , Sulfonas/química
15.
J Org Chem ; 79(14): 6627-33, 2014 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-24988133

RESUMEN

ortho-Aminated vinylarene derivatives were obtained via a reaction of aryl iodides, N-benzoyloxyamines, and N-tosylhydrazones. This approach involves a palladium-catalyzed, norbornene-mediated ortho-amination/N-tosylhydrazone insertion reaction. In this transformation, one C-N bond and one C-C bond are formed and an amine group is introduced at the ortho position successfully.

16.
Sci Total Environ ; 935: 173303, 2024 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-38761948

RESUMEN

Cadmium (Cd) and sulfamethoxazole (SMX) frequently coexist in farmlands, yet their synergistic toxicological impacts on terrestrial invertebrates remain unexplored. In this study, earthworms were exposed to artificial soils percolated with Cd (5 mg/kg), SMX (5 mg/kg) or combination of them for 7 days, followed by a 12-day elimination phase in uncontaminated soil. The uptake of Cd and SMX by the earthworms, along with their subcellular distribution, was meticulously analyzed. Additionally, a suite of biomarkers-including superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and weight loss-were evaluated to assess the health status of the earthworms and the toxicological effects of the Cd and SMX mixture. Notably, the cotreatment with Cd and SMX resulted in a significantly higher weight loss in Eisenia fetida (41.25 %) compared to exposure to Cd alone (26.84 %). Moreover, the cotreatment group exhibited substantially higher concentrations of Cd in the total internal body, fraction C (cytosol), and fraction E (tissue fragments and cell membranes) in Eisenia fetida compared to Cd alone counterparts. The combined exposure also significantly elevated the SMX levels in the total body and fraction C compared with the SMX-only treated earthworms. Additionally, Eisenia fetida subjected to the combined treatment showed markedly increased activities of SOD, CAT, and MDA compared to those treated with Cd alone. The effect addition indices (EAIs), ranging from 1.00 to 2.23, unequivocally demonstrated a synergistic effect of the combined treatments. Interestingly, relocating the earthworms to clean soil did not mitigate the observed adverse effects. These findings underscore the increased risk posed by the Cd-SMX complex to terrestrial invertebrates in agricultural areas.


Asunto(s)
Biomarcadores , Cadmio , Oligoquetos , Contaminantes del Suelo , Sulfametoxazol , Oligoquetos/efectos de los fármacos , Oligoquetos/fisiología , Animales , Sulfametoxazol/toxicidad , Cadmio/toxicidad , Contaminantes del Suelo/toxicidad , Biomarcadores/metabolismo , Malondialdehído/metabolismo , Superóxido Dismutasa/metabolismo , Catalasa/metabolismo
17.
Front Neurol ; 13: 893089, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35645947

RESUMEN

Background: The pharmacokinetics of vancomycin in cerebrospinal fluid (CSF) is an important basis for evaluating the bactericidal effect. The accuracy of using serum vancomycin concentrations only to estimate the CSF concentrations remains controversial, may lead to underdosing. Objectives: The aims of this study were to evaluate the vancomycin exposure in CSF, investigate the factors affecting the vancomycin blood-brain barrier (BBB) penetration, and to establish the prediction model of vancomycin concentration in CSF. Methods: Eligible patients were included and given a standard dose of vancomycin. At the fifth dose, the blood and CSF samples were collected 0.5 h before the start of infusion of vancomycin, and 1, 2, 3, and 8 h from the start of infusion, and were measured by the enzyme-multiplied immunoassay technique using the Siemens Viva-E Drug Testing System. Results: The AUCCSF/serum of patients with intracranial infection was higher than that of patients without (p = 0.001). The CSF concentration was relatively stable between dosing periods (p = 0.095). The area under the concentration-time curve (AUC) ratio of CSF to serum (AUCCSF/serum) in patients with intracranial infection ranged from 15.1 to 80.1% (33.23 ± 19.31%; median, 26.25%). The CSF vancomycin AUC levels were affected by the serum trough concentration (B: 5.23 ± 2.36, t = 2.22, p = 0.039), and were mainly affected by the CSF white blood cells (WBCs)/total cells (B: 113.96 ± 35.10, t = 3.25, p = 0.004) (Y = -17.86 + 5.23 × serum trough concentration + 113.96 × CSF [WBCs/total cells]; R 2 = 0.473, F = 8.542, p = 0.002). Conclusions: After intravenous administration of vancomycin, the CSF concentration curve was fluctuated gently. The CSF vancomycin concentration in patients with postoperative intracranial infection can be predicted by the WBCs to total cells ratio and the serum trough concentration, and help to adjust the administration of vancomycin.

18.
Huan Jing Ke Xue ; 43(10): 4789-4800, 2022 Oct 08.
Artículo en Zh | MEDLINE | ID: mdl-36224164

RESUMEN

The inoculation of antibiotic-degrading bacteria into manure could promote the removal of antibiotics during composting. However, knowledge on the impact of inoculating these antibiotic-degrading bacteria on the composting process and indigenous microbial community succession is still limited. This study assessed the antibiotic removal efficiency in pig manure after inoculating a microbial inoculum with antibiotic-degrading bacteria as the key component. The effect of inoculating this microbial inoculum on the physicochemical dynamics and the succession of the manure bacterial community during composting was also analyzed. The results showed that the antibiotic degradation in pig manure reached 81.95% after inoculating the microbial inoculum. When compared with that in the control, the total concentration of antibiotic residues in manure with the microbial agent inoculated was decreased by 42.18%. During composting, inoculating the microbial inoculum accelerated the temperature rise of compost, favored water loss, and alleviated the release of NH3 and H2S. Moreover, the total nutrient content (nitrogen, phosphorus, and potassium) in the final compost and the germination index of radish seeds increased by 6.80% and 68.33%, respectively, after inoculating this microbial inoculum. Furthermore, inoculating the microbial inoculum increased the content of stable organic carbon in the final compost and decreased the content of recalcitrant substances such as cellulose and hemicellulose. The analysis of the manure bacterial community showed that inoculating the microbial inoculum increased the relative abundances of Actinomycetes and Firmicutes in the compost. In particular, the thermophilic bacteria that was positively related to the compost temperature was increased significantly (P<0.01) after inoculating the microbial inoculum, whereas the relative abundance of pathogenic bacteria was correspondingly decreased. Network analysis of the bacterial coexistence pattern showed that inoculating this microbial inoculum also changed the interaction pattern of indigenous manure bacterial communities, which greatly reduced the complexity and connectivity of the bacterial interaction and improved the ecological relationship between beneficial bacteria and other bacterial communities. The effect of this microbial inoculum on the interaction with manure bacterial community laid a foundation for the establishment of a new and healthier composting bacterial community. This study provides a scientific basis for the application and development of multifunctional antibiotic-degrading microbial agents in manure treatments.


Asunto(s)
Compostaje , Animales , Antibacterianos/análisis , Bacterias , Carbono , Celulosa , Estiércol/microbiología , Nitrógeno/análisis , Fósforo , Potasio , Suelo , Porcinos , Agua/análisis
19.
Huan Jing Ke Xue ; 43(10): 4779-4788, 2022 Oct 08.
Artículo en Zh | MEDLINE | ID: mdl-36224163

RESUMEN

The key point in facing the demand for the disposal of waste storage in rural areas of China is to manage informal landfills. However, limited studies have been conducted to evaluate the phytoremediation efficiency of heavy metal and polycyclic aromatic hydrocarbon (PAHs) co-contaminated dumpsite soil with high ammonia nitrogen content. In this study, we selected the tolerant plant legume alfalfa (Medicago sativa L.) for a pot experiment to investigate the effects of nitrogen (N) (0, 10, and 50 mg·kg-1) on plant growth, the removal of pollutants, and soil bacterial community structure in Cd-PAHs co-contaminated soil, so as to evaluate the role of N in the process of phytoremediation of dumpsite soil. The results showed that the biomass of alfalfa under high co-contamination conditions (Cd:10 mg·kg-1 and PAHs:400 mg·kg-1) increased with N supply and was 6.0 and 6.3 times higher than that of the treatment without N supply, respectively. Furthermore, the lower N level promoted the growth of alfalfa in the low-contamination group (Cd:1 mg·kg-1 and PAHs:100 mg·kg-1), but the difference was not significant, and a high concentration of N significantly inhibited its growth. In addition, the phytoremediation efficiency for Cd in the low-contamination group ranged from 5.58% to 7.49%, and N significantly increased the efficiency in the high co-contamination group from 0.95% to 3.02%. Compared with the removal of phenanthrene, N had a stronger influence on the removal of pyrene. Meanwhile, alfalfa could promote the removal of them in soil, among which the degradation of PAHs by microorganisms was dominant, whereas the contribution of the plant uptake pathway was less than 0.21%. As reflected by distance-based redundancy analysis (db-RDA), PAHs and Cd were the main factors affecting the structure of the microbial community; moreover, N had a greater effect on bacterial community composition in the single Cd-contamination and high co-contamination groups, promoting genera with bioremediation effects as the dominant soil bacterial communities, including Arthrobacter, Microbacterium, and Novosphingobium. This study will provide a theoretical basis for the remediation of dumpsites as well as informal landfills with contaminated soil.


Asunto(s)
Metales Pesados , Fenantrenos , Hidrocarburos Policíclicos Aromáticos , Contaminantes del Suelo , Amoníaco/metabolismo , Biodegradación Ambiental , Cadmio/análisis , Medicago sativa , Metales Pesados/análisis , Nitrógeno/análisis , Fenantrenos/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Pirenos/análisis , Suelo/química , Microbiología del Suelo , Contaminantes del Suelo/análisis
20.
Huan Jing Ke Xue ; 42(10): 4959-4967, 2021 Oct 08.
Artículo en Zh | MEDLINE | ID: mdl-34581140

RESUMEN

Denitrification is a key process in the nitrogen cycle of ecosystems. Most existing studies of nitrogen emissions and denitrifying bacterial communities are carried out in ecosystems with significant human interference, yet few focus in natural ecosystems with low human disturbance. Here, the denitrification rates and characteristics of nirS-type denitrifying bacterial communities in rhizosphere and bulk soils from alpine wetland plants at different altitudes(Tangke, Jiuzhi, Maduo, and Dari) and seasons(spring and summer) in the Yellow River source region of the Qinghai-Tibet Plateau were investigated. The 15N isotope tracer technique was used to estimate the denitrification rates, and high-throughput sequencing technology was used to determine the composition and relative abundance of nirS-type denitrifying bacterial communities. We also investigated the environmental factors(temperature and altitude) and soil physical and chemical properties(pH, soil organic carbon, ammonia, nitrate, and nitrite) controlling the denitrification and related microorganisms. The results show that the denitrification rates of alpine wetland soils ranged from 0.80 to 14.98 nmol·(g·h)-1, and the contribution to the total N2 production ranged from 11.23% to 71.16%. The soil samples from Tangke, Jiuzhi, and Dari showed higher denitrification rates in rhizosphere soils than the corresponding bulk soils(P<0.05). Proteobacteria was the most dominate denitrifying bacteria phylum. At the genus level, unclassified Proteobacteria(2.86%-29.41%) showed the highest relative abundance, indicating that unique unidentified bacteria may dominate denitrification in these wetland soils. The genera with the next highest relative abundances were Pseudomonas(2.45%-26.52%) and Cupriavidus(0%-34.14%). Distance-based redundancy analysis showed that the community structure of the nirS-type denitrifying bacteria was mainly affected by altitude, pH, and nitrite concentrations; Pearson correlation analysis showed that denitrification rates and the Shannon index are significantly negatively correlated with soil pH(P<0.05), and the relative abundance of the main denitrifying bacterial genera were influenced by temperature and soil pH(P<0.05). This study provides valuable insights for understanding the nitrogen cycle in the unique alpine wetlands of the Qinghai-Tibet Plateau.


Asunto(s)
Suelo , Humedales , Bacterias/genética , Carbono , Desnitrificación , Ecosistema , Humanos , Rizosfera , Estaciones del Año , Microbiología del Suelo , Tibet
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