Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 577
Filtrar
1.
J Microbiol Biotechnol ; 32(1)2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34818665

RESUMO

Tetanus is a potentially fatal public health illness resulted from the neurotoxins generated by Clostridium tetani. C. tetani is not easily culturable and culturing the relevant bacteria from infected wounds has rarely been useful in diagnosis; PCR-based assays can only be conducted at highly sophisticated laboratories. Therefore, a real-time recombinase polymerase amplification assay (Exo-RPA) was constructed to identify the fragments of the neurotoxin gene of C. tetani. Primers and the exo probe targeting the conserved region were designed, and the resulting amplicons could be detected in less than 20 min, with a detection limit of 20 copies/reaction. The RPA assay displayed good selectivity, and there were no cross-reactions with other infectious bacteria common in penetrating wounds. Tests of target-spiked serum and pus extract revealed that RPA is robust to interfering factors and has great potential for further development for biological sample analysis. This method has been confirmed to be reliable for discriminating between toxic and nontoxic C. tetani strains. The RPA assay dramatically improves the diagnostic efficacy with simplified device architecture and is a promising alternative to real-time PCR for tetanus detection.

2.
Anim Nutr ; 7(4): 1337-1344, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34786506

RESUMO

In biological responses, fatty acids (FA) are absorbed and metabolized in the form of substrates for energy production. The molecular structures (number of double bonds and chain length) and composition of dietary FA impact digestion, absorption and metabolism, and the biological roles of FA. Recently, increasing evidence indicates that FA are essentially utilized as an energy source and are signaling molecules that exert physiological activity of gut microbiota and immune responses. In addition, FA could serve as natural ligands for orphan G protein-coupled receptors (GPCR), also called free fatty acid receptors (FFAR), which intertwine metabolic and immune systems via multiple mechanisms. The present review explores the recent findings on FA absorption and its impact on gut health, particularly addressing the mechanism by which dietary FA potentially influences intestinal microbiota and epithelial functions. Also, this work attempts to uncover research ideas for devising future strategies for manipulating the composition of dietary FA to regulate gut health and support a normal immune system for metabolic and immune disorders.

3.
Sci Total Environ ; : 151411, 2021 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-34742985

RESUMO

Gas/particle (G/P) partitioning is an important influencing factor for the environmental fate of semi-volatile organic compounds (SVOCs). The G/P partitioning of polycyclic aromatic hydrocarbons (PAHs) is an integrated complex process due to its formation and growth concurrently with particles. Based on the large dataset of gaseous and particulate samples in a wide ambient temperature range of 50 °C, the simple empirical equations based on ambient temperature were established to predict the G/P partitioning quotient (KP) of PAHs at the temperature range from 252 K to 307 K (-21 °C to 34 °C). The performance of the empirical equations was validated by comparison with the monitoring KP of PAHs worldwide. The empirical equations exhibited good performance for the prediction of KP of PAHs based on ambient temperature. Two deviations with the prediction lines of the previous G/P partitioning models from the monitoring data of KP were observed. It was found that the deviations might be attributed to some non-considered influencing factors with the previous G/P partitioning prediction models. Therefore, further research should be conducted to study the mechanism of the G/P partitioning of PAHs, and more influencing factors should be introduced into the establishment of G/P partitioning models of PAHs. In summary, the result of the present study provided a convenient method for the prediction of KP of PAHs, which should be useful for the study of environmental fate of PAHs in atmosphere.

4.
J Pharm Anal ; 11(5): 628-637, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34765276

RESUMO

Berberine (BBR) is an isoquinoline alkaloid extracted from Coptis chinensis that improves diabetes, hyperlipidemia and inflammation. Due to the low oral bioavailability of BBR, its mechanism of action is closely related to the gut microbiota. This study focused on the CYP51 enzyme of intestinal bacteria to elucidate a new mechanism of BBR transformation by demethylation in the gut microbiota through multiple analytical techniques. First, the docking of BBR and CYP51 was performed; then, the pharmacokinetics of BBR was determined in ICR mice in vivo, and the metabolism of BBR in the liver, kidney, gut microbiota and single bacterial strains was examined in vitro. Moreover, 16S rRNA analysis of ICR mouse feces indicated the relationship between BBR and the gut microbiota. Finally, recombinant E. coli containing cyp51 gene was constructed and the CYP51 enzyme lysate was induced to express. The metabolic characteristics of BBR were analyzed in the CYP51 enzyme lysate system. The results showed that CYP51 in the gut microbiota could bind stably with BBR, and the addition of voriconazole (a specific inhibitor of CYP51) slowed down the metabolism of BBR, which prevented the production of the demethylated metabolites thalifendine and berberrubine. This study demonstrated that CYP51 promoted the demethylation of BBR and enhanced its intestinal absorption, providing a new method for studying the metabolic transformation mechanism of isoquinoline alkaloids in vivo.

5.
J Asian Nat Prod Res ; : 1-8, 2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34747287

RESUMO

A new dihydroflavone, 2(S)-isookanin-4'-methoxy-8-O-ß-D-glucopyranoside (1), and a new polyacetylene glucoside, (10S)-tridecane-2E-ene-4,6,8-triyne-1-ol-10-O-ß-D-glucopyranoside (2), along with seven known compounds (3-9), were isolated from the herb of Bidens parviflora Willd. The structures of all the extracted compounds were elucidated by HR-ESI-MS, 1 D and 2 D NMR spectra, as well as circular dichroism (CD).

6.
Biology (Basel) ; 10(11)2021 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-34827137

RESUMO

Cyanobacteria bloom caused by water eutrophication has threatened human health and become a global environmental problem. To develop green algicides with strong specificity and high efficiency, three series of ester and amide derivatives from parent allelochemicals of caffeic acid (CA), cinnamic acid (CIA), and 3-hydroxyl-2-naphthoic acid (HNA) were designed and synthesized. Their inhibitory effects on the growth of five harmful cyanobacterial species, Microcystis aeruginosa (M. aeruginosa), Microcystis wesenbergii (M. wesenbergii), Microcystis flos-aquae (M. flos-aquae), Aphanizomenon flos-aquae (Ap. flos-aquae), and Anabaena flos-aquae (An. flos-aquae), were evaluated. The results revealed that CIA esters synthesized by cinnamic acid and fatty alcohols showed the best inhibition effect, with EC50 values ranging from 0.63 to >100 µM. Moreover, some CIA esters exhibited a good selectivity in inhibiting cyanobacteria. For example, the inhibitory activity of naphthalen-2-yl cinnamate was much stronger on Ap. flos-aquae (EC50 = 0.63 µM) than other species (EC50 > 10 µM). Three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis was performed and the results showed that the steric hindrance of the compounds influenced the algicidal activity. Further mechanism study found that the inhibition of CIA esters on the growth of M. aeruginosa might be related to the accumulation of malondialdehyde (MDA).

7.
Front Plant Sci ; 12: 757516, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34777436

RESUMO

The biosynthesis of flavonoids and anthocyanidins has been exclusively investigated in angiosperms but largely unknown in ferns. This study integrated metabolomics and transcriptome to analyze the fronds from different development stages (S1 without spores and S2 with brown spores) of Cyclosorus parasiticus. About 221 flavonoid and anthocyanin metabolites were identified between S1 and S2. Transcriptome analysis revealed several genes encoding the key enzymes involved in the biosynthesis of flavonoids, and anthocyanins were upregulated in S2, which were validated by qRT-PCR. Functional characterization of two chalcone synthases (CpCHS1 and CpCHS2) indicated that CpCHS1 can catalyze the formation of pinocembrin, naringenin, and eriodictyol, respectively; however, CpCHS2 was inactive. The crystallization investigation of CpCHS1 indicated that it has a highly similar conformation and shares a similar general catalytic mechanism to other plants CHSs. And by site-directed mutagenesis, we found seven residues, especially Leu199 and Thr203 that are critical to the catalytic activity for CpCHS1.

8.
Front Genet ; 12: 733871, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34603394

RESUMO

The N6-methyladenosine (m6A) modification is the most abundant epitranscriptomic modification in eukaryotic messenger RNA (mRNA). The m6A modification process is jointly regulated by various enzymes and proteins, such as methyltransferases, demethylases and related m6A-binding proteins. The process is dynamic and reversible, and it plays an essential role in mRNA metabolism and various biological activities. Recently, an increasing number of researchers have confirmed that the onset and development of many diseases are closely associated with the molecular biological mechanism of m6A RNA methylation. This study focuses on the relationship between m6A RNA modification and atherosclerosis (AS). It thoroughly summarizes the mechanisms and processes of m6A RNA modification in AS-related cells and the relationships between m6A RNA modification and AS risk factors, and it provides a reference for exploring new targets for the early diagnosis and treatment of AS.

9.
J Environ Sci (China) ; 109: 219-236, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34607670

RESUMO

Certain poly- and perfluoroalkyl substances (PFASs) exhibit significant bioaccumulation/biomagnification behaviors in ecosystems. PFASs, such as perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS) and related precursors, have elicited attention from both public and national regulatory agencies, which has resulted in worldwide restrictions on their production and use. Apex predators occupy the top trophic positions in ecosystems and are most affected by the biomagnification behavior of PFASs. Meanwhile, the long lifespans of apex predators also lead to the high body burden of PFASs. The high body burden of PFASs might be linked to adverse health effects and even pose a potential threat to their reproduction. As seen in previous reviews of PFASs, knowledge is lacking between the current stage of the PFAS body burden and related effects in apex predators. This review summarized PFAS occurrence in global apex predators, including information on the geographic distribution, levels, profiles, and tissue distribution, and discussed the trophic transfer and ecotoxicity of PFASs. In the case where legacy PFASs were restricted under international convention, the occurrence of novel PFASs, such as 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) and perfluoroethylcyclohexane sulfonate (PFECHS), in apex predators arose as an emerging issue. Future studies should develop an effective analytical method and focus on the toxicity and trophic transfer behavior of novel PFASs.


Assuntos
Ácidos Alcanossulfônicos , Fluorcarbonetos , Ecossistema , Fluorcarbonetos/análise , Fluorcarbonetos/toxicidade , Distribuição Tecidual
10.
Sci Rep ; 11(1): 19983, 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34620980

RESUMO

The mud cake is easily formed during the tunnel boring machine (TBM) excavation in clay soils or rocks containing clay minerals. Mud cake will lead to soil disturbance of tunnel face, clogging cutterhead and even affect the construction efficiency and personnel safety. In this study, a discrimination method of mud cake formation based on cutterhead temperature was proposed. An online monitoring system was designed and installed on the slurry balance TBM. The results show that: (a) the cutterhead temperature data can be reliably detected and transmitted by the system; (b) in a tunneling cycle, the temperature at some positions of the cutterhead will increase first and then decrease; (c) during the field test, the temperature variation is around 2.5 °C under the normal condition, but the temperature variation will increase more than 50 °C due to the mud cake or geological change; (d) compared with the cooling rate, mud cake formation can be accurately discriminated.

11.
Nat Commun ; 12(1): 5980, 2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34645825

RESUMO

While self-healing is considered a promising strategy to achieve long-term stability for oxygen evolution reaction (OER) catalysts, this strategy remains a challenge for OER catalysts working in highly alkaline conditions. The self-healing of the OER-active nickel iron layered double hydroxides (NiFe-LDH) has not been successful due to irreversible leaching of Fe catalytic centers. Here, we investigate the introduction of cobalt (Co) into the NiFe-LDH as a promoter for in situ Fe redeposition. An active borate-intercalated NiCoFe-LDH catalyst is synthesized using electrodeposition and shows no degradation after OER tests at 10 mA cm-2 at pH 14 for 1000 h, demonstrating its self-healing ability under harsh OER conditions. Importantly, the presence of both ferrous ions and borate ions in the electrolyte is found to be crucial to the catalyst's self-healing. Furthermore, the implementation of this catalyst in photoelectrochemical devices is demonstrated with an integrated silicon photoanode. The self-healing mechanism leads to a self-limiting catalyst thickness, which is ideal for integration with photoelectrodes since redeposition is not accompanied by increased parasitic light absorption.

12.
J Colloid Interface Sci ; 608(Pt 1): 306-312, 2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34626977

RESUMO

Rational designing and synthesizing highly efficient oxygen evolution reaction (OER) electrocatalyst plays a key role in energy conversion. However, due to the numerous factors affecting the activity of electrocatalysis, the understanding of their catalytic mechanism is insufficient, and challenges still exist. Herein, the organic group of the metal-organic nanosheets electrocatalyst was replaced by NH2 to CH3 to controllable regulate the catalytic performance of OER, corresponding to the overpotential of OER reducing from 385 mV to 318 mV at 10 mA cm-2, superior to the commercial precious metal based catalyst RuO2. Furthermore, combining the density functional theory (DFT) and electron localization function (ELF) indicates that the type of ligands group can indirectly modulate the electronic structure of metal catalytic center and the degree of electronic localization of the metal-organic nanosheets catalysts, resulting in the change in electrocatalytic activity. This simple catalytic model is more favorable to investigate the catalytic mechanism, providing a new strategy for the development of efficient electrocatalyst.

13.
Small ; : e2103178, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34655176

RESUMO

The development of high-efficiency, robust, and available electrode materials for oxygen evolution reaction (OER) and lithium-ion batteries (LIBs) is critical for clean and sustainable energy system but remains challenging. Herein, a unique yolk-shell structure of Fe2 O3 nanotube@hollow Co9 S8 nanocage@C is rationally prepared. In a prearranged sequence, the fabrication of Fe2 O3 nanotubes is followed by coating of zeolitic imidazolate framework (ZIF-67) layer, chemical etching of ZIF-67 by thioacetamide, and eventual annealing treatment. Benefiting from the hollow structures of Fe2 O3 nanotubes and Co9 S8 nanocages, the conductivity of carbon coating and the synergy effects between different components, the titled sample possesses abundant accessible active sites, favorable electron transfer rate, and exceptional reaction kinetics in the electrocatalysis. As a result, excellent electrocatalytic activity for alkaline OER is achieved, which delivers a low overpotential of 205 mV at the current density of 10 mA cm-2 along with the Tafel slope of 55 mV dec-1 . Moreover, this material exhibits excellent high-rate capability and excellent cycle life when employed as anode material of LIBs. This work provides a novel approach for the design and the construction of multifunctional electrode materials for energy conversion and storage.

14.
Front Nutr ; 8: 751010, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34660671

RESUMO

Animal antimicrobial peptides (AMPs), known as broad-spectrum and high-efficiency antibacterial activity, are important effector molecules in innate immune system. AMPs not only have antimicrobial, antiviral and antitumor effects but also exhibit important effects in vivo, such as anti-inflammatory response, recruiting immune cells, promoting epithelial damage repair, and promoting phagocytosis of bacteria. However, research on the application of AMPs is incomplete and controversial. This review mainly introduces the classification of AMPs, biological functions, as well as the mechanisms of action, expression rules, and nutrition regulation from three perspectives, aiming to provide important information for the application of AMPs.

15.
Pain Physician ; 24(7): E1075-E1083, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34704717

RESUMO

BACKGROUND: Computed tomography (CT)-guided radiofrequency thermocoagulation of lumbar sympathetic nerve has been gradually applied to the treatment of many autonomic nerve disorders, such as plantar hyperhidrosis (PH) and diabetic peripheral neuropathy (DPN). The difference in the success rate of operation between the left and right sides is not yet studied. OBJECTIVE: This study aimed to explore a statistically significant difference between the success rate of left and right CT-guided radiofrequency thermocoagulation of lumbar sympathetic nerve and screen the risk factors affecting the success rate of the right surgery. STUDY DESIGN: This is a single-center retrospective cohort study. SETTING: The study was carried out in the Pain Department of the affiliated Hospital of Jiaxing College in Jiaxing, China. METHODS: A total of 86 patients who received CT-guided radiofrequency thermocoagulation of lumbar sympathetic nerve were included in this study approved by the Ethics Committee of the affiliated Hospital of Jiaxing University. Nonparametric and chi-square tests were used to compare the operation times, CT scan times, and success rate on the left and right sides. Binary multivariate logistic regression analysis was applied to screen the risk factors on the outcome variable. RESULTS: The bilateral operation time, CT scan times, and success rate differed significantly between the left and right sides (P < 0.05). After univariate analysis, 6 covariates (gender, body mass index, treatment history, operation time, CT scan times, and puncture needle type) were selected. Finally, the multivariate regression model screened out 2 risk factors: the operation time and puncture needle type. LIMITATIONS: We look forward to increasing the sample size in follow-up studies and exploring relevant conclusions in randomized controlled trials. CONCLUSION: This study proved that in CT-guided radiofrequency thermocoagulation of the lumbar sympathetic nerve, the difficulty of operation on the right side was significantly high, and the success rate was also lower than that on the contralateral side. Multivariate logistic regression analysis showed that operation time and type of puncture needle were risk factors affecting the success rate of the operation. These findings laid a foundation for the accomplishment of technical improvement and innovation in the future. A preliminary exploration was carried out to reduce the risk and complications and to improve the success rate of the operation.

16.
Microb Biotechnol ; 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34704376

RESUMO

Faecal Microbiota Transplantation (FMT) is considered as a promising technology to fight against obesity. Wild boar has leanermuscle and less fat in comparison to the domestic pig, which were thought to be related with microbiota. To investigate the function and mechanism of the wild boar microbiota on obesity, we first analysed the wild boar microbiota composition via 16S rDNA sequencing, which showed that Firmicutes and Proteobacteria were the dominant bacteria. Then, we established a high-fat diet (HFD)-induced obesity model, and transfer low and high concentrations of wild boar faecal suspension in mice for 9 weeks. The results showed that FMT prevented HFD-induced obesity and lipid metabolism disorders, and altered the jejunal microbiota composition especially increasing the abundance of the Lactobacillus and Romboutsia, which were negatively correlated with obesity-related indicators. Moreover, we found that the anti-obesity effect of wild boar faecal suspension was associated with jejunal N6-methyladenosine (m6 A) levels. Overall, these results suggest that FMT has a mitigating effect on HFD-induced obesity, which may be due to the impressive effects of FMT on the microbial composition and structure of the jejunum. These changes further alter intestinal lipid metabolism and m6 A levels to achieve resistance to obesity.

17.
ACS Omega ; 6(36): 23222-23232, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34549123

RESUMO

Various analytical techniques are used to study the weathering process of four crude oils, i.e., Iranian light crude oil, Daqing crude oil, Shengli crude oil, and Tahe crude oil. The molecular composition and structural information of n-alkanes, polycyclic aromatic hydrocarbons (PAHs), and heteroatom compounds were characterized by gas chromatography-flame ionization detector (GC-FID), gas chromatography-mass spectrometry (GC-MS), and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), respectively. The results showed that the weathering loss of n-alkanes was related to the molecular weight, and the low-molecular-weight (LMW) n-alkanes were more volatile. The loss degree of LMW naphthalene and alkylation homologues in PAHs was also higher. With the increase in the alkylation degree, the weathering resistance ability of PAHs was enhanced. In the negative-ion ESI FT-ICR MS mode, a total of 16 classes of compounds were detected for neutral nitrogen compounds and acidic compounds in the four crude oils. With the increase in weathering time, the relative abundances of NO, NO2, and O3S compounds gradually increased. In particular, the NO and NO2 compounds with different condensation degrees increased significantly. These results indicated that in addition to the volatilization of hydrocarbon compounds, nitrogen compounds were also oxidized to a certain extent during the weathering process. The provided information would enrich the understanding of the short-term weathering process of petroleum hydrocarbons.

18.
J Hazard Mater ; 416: 125887, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34492825

RESUMO

The effects of temperature and power on product distribution and characteristics of oily sludge (OS) pyrolysis were investigated in a microwave reactor. The maximum oil yield was 72.55 wt% at 550 °C and 71.47 wt% at 800 W, respectively. X-ray photoelectron spectroscopy (XPS) indicated that C-C and C-O were the main forms of carbon in OS char (OC). The sulfur (S) content in OC increased as the temperature/power rose, implying that S might exist in the form of inorganics or OC had S retention ability. In temperature control mode, the changes of functional groups on OC surface were more sensitive. The maximum hydrocarbon content in oil was 14.56% at 350 °C and 13.40% at 900 W, respectively. The contents of oxygenated compounds and heterocycles in oil from temperature control mode were higher. The CO yield increased with increasing temperature/power, reaching the maximum of 9.60 wt% at 650 °C and 7.75 wt% at 900 W, respectively. Compared with power control mode, it seemed that more heavy metals (HMs) were retained in OC in temperature control mode. The Er of HMs were at the clean level and RI indicated the HMs in OC had a low environmental risk.


Assuntos
Metais Pesados , Pirólise , Micro-Ondas , Esgotos , Temperatura
20.
PeerJ ; 9: e12141, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34567847

RESUMO

Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most commonly diagnosed cancers with a poor prognosis worldwide. Although the treatment of PDAC has made great progress in recent years, the therapeutic effects are still unsatisfactory. Methods. In this study, we identified differentially expressed genes (DEGs) between PDAC and normal pancreatic tissues based on four Gene Expression Omnibus (GEO) datasets (GSE15471, GSE16515, GSE28735 and GSE71729). A protein-protein interaction (PPI) network was established to evaluate the relationship between the DEGs and to screen hub genes. The expression levels of the hub genes were further validated through the Gene Expression Profiling Interactive Analysis (GEPIA), ONCOMINE and Human Protein Atlas (HPA) databases, as well as the validation GEO dataset GSE62452. Additionally, the prognostic values of the hub genes were evaluated by Kaplan-Meier plotter and the validation GEO dataset GSE62452. Finally, the mechanistic roles of the most remarkable hub genes in PDAC were examined through in vitro experiments. Results: We identified the following nine hub genes by performing an integrated bioinformatics analysis: COL1A1, COL1A2, FN1, ITGA2, KRT19, LCN2, MMP9, MUC1 and VCAN. All of the hub genes were significantly upregulated in PDAC tissues compared with normal pancreatic tissues. Two hub genes (FN1 and ITGA2) were associated with poor overall survival (OS) rates in PDAC patients. Finally, in vitro experiments indicated that FN1 plays vital roles in PDAC cell proliferation, colony formation, apoptosis and the cell cycle. Conclusions: In summary, we identified two hub genes that are associated with the expression and prognosis of PDAC. The oncogenic role of FN1 in PDAC was first illustrated by performing an integrated bioinformatic analysis and in vitro experiments. Our results provide a fundamental contribution for further research aimed finding novel therapeutic targets for overcoming PDAC.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...