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1.
Mol Cells ; 2021 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-33820882

RESUMO

Metallothionein (MT1M) belongs to a family of cysteine-rich cytosolic protein and has been reported to be a tumor suppressor gene in multiple cancers. However, its role in esophageal carcinoma carcinogenesis remains unclear. In this study, MT1M expression was correlated with tumor type, stage, drinking and smoking history, as well as patient survival. We also studied the regulation and biological function of MT1M in esophageal squamous cell carcinoma (ESCC). We have found that MT1M is significantly downregulated in ESCC tissues compared with adjacent non-cancer tissues. Furthermore, restoration of expression by treatment with the demethylation agent A + T showed that MT1M downregulation might be closely related to hypermethylation in its promoter region. Over-expression of MT1M in ESCC cells significantly altered cell morphology, induced apoptosis, and reduced colony formation, cell viability, migration and epithelial-mesenchymal transition. Moreover, based on reactive oxygen species (ROS) levels, a superoxide dismutase 1 (SOD1) activity assay and protein analysis, we verified that the tumor-suppressive function of MT1M was at least partially caused by its upregulation of ROS levels, downregulation of SOD1 activity and phosphorylation of the SOD1 downstream pathway PI3K/AKT. In conclusion, our results demonstrated that MT1M was a novel tumor-suppressor in ESCC and may be disrupted by promoter CpG methylation during esophageal carcinogenesis.

3.
Adipocyte ; 10(1): 160-173, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33794740

RESUMO

Obesity is characterized by low-grade chronic inflammation, which underlies insulin resistance and non-alcoholic fatty liver disease (NAFLD). Swertiamarin is a secoiridoid glycoside that has been reported to ameliorate diabetes and NAFLD in animal models. However, the effects of swertiamarin on obesity-related inflammation and insulin resistance have not been fully elucidated. Thus, this study investigated the effects of swertiamarin on inflammation and insulin resistance in high-fat diet (HFD)-induced obese mice. C57BL/6 mice were fed a HFD or HFD containing swertiamarin for 8 weeks. Obesity-induced insulin resistance and inflammation were assessed in the epididymal white adipose tissue (eWAT) and livers of the mice. Swertiamarin attenuated HFD-induced weight gain, glucose intolerance, oxidative stress, and insulin resistance, and enhanced insulin signalling in mice. Compared to HFD-fed mice, the swertiamarin-treated mice exhibited increased lipolysis and reduced adipocyte hypertrophy and macrophage infiltration in eWAT. Moreover, swertiamarin alleviated HFD-mediated hepatic steatosis and inflammation by suppressing activation of the p38 MAPK and NF-κB pathways within the eWAT and liver of obese mice. In conclusion, supplementation with swertiamarin attenuated weight gain and hepatic steatosis, and alleviated obesity-associated inflammation and insulin resistance, in obese mice.

4.
Inorg Chem ; 2021 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-33715352

RESUMO

A copper-containing polyoxometalate-based metal-organic framework (POMOF), CuI12Cl2(trz)8[HPW12O40] (HENU-7, HENU = Henan University; trz = 1,2,4-triazole), has been successfully synthesized and well-characterized. In addition, the excellent catalytic ability of HENU-7 has been proved by the selective oxidation of diphenylmethane. Under the optimal conditions, the diphenylmethane conversion obtained over HENU-7 is 96%, while the selectivity to benzophenone is 99%, which outperforms most noble-metal-free POM-based catalysts. Moreover, HENU-7 is stable to reuse for five runs without an obvious loss in activity and also can catalyze the oxidation of different benzylic C-H with satisfactory conversions and selectivities, which implied the significant catalytic activity and recyclability.

5.
ACS Nano ; 15(3): 5735-5751, 2021 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-33705663

RESUMO

As next-generation artificial enzymes, nanozymes have shown great promise for tumor catalytic therapy. In particular, their peroxidase-like activity has been employed to catalyze hydrogen peroxide (H2O2) to produce highly toxic hydroxyl radicals (•OH) to kill tumor cells. However, limited by the low affinity between nanozymes with H2O2 and the low level of H2O2 in the tumor microenvironment, peroxidase nanozymes usually produced insufficient •OH to kill tumor cells for therapeutic purposes. Herein, we present a pyrite peroxidase nanozyme with ultrahigh H2O2 affinity, resulting in a 4144- and 3086-fold increase of catalytic activity compared with that of classical Fe3O4 nanozyme and natural horseradish peroxidase, respectively. We found that the pyrite nanozyme also possesses intrinsic glutathione oxidase-like activity, which catalyzes the oxidation of reduced glutathione accompanied by H2O2 generation. Thus, the dual-activity pyrite nanozyme constitutes a self-cascade platform to generate abundant •OH and deplete reduced glutathione, which induces apoptosis as well as ferroptosis of tumor cells. Consequently, it killed apoptosis-resistant tumor cells harboring KRAS mutation by inducing ferroptosis. The pyrite nanozyme also exhibited favorable tumor-specific cytotoxicity and biodegradability to ensure its biosafety. These results indicate that the high-performance pyrite nanozyme is an effective therapeutic reagent and may aid the development of nanozyme-based tumor catalytic therapy.

6.
Artigo em Inglês | MEDLINE | ID: mdl-33689262

RESUMO

Lightweight structures are often used for applications requiring higher strength-to-weight ratios and lower densities, such as in aircraft, vehicles, and various engine components. Three-dimensional (3D) printing technology has been widely used for lightweight polymer structures because of the superior flexibility, personalized design, and ease of operation offered by it. However, synthesis of lightweight polymeric structures that possess both high specific strength and glass transfer temperature (Tg) remains an elusive goal, because 3D printed polymers with these properties are still very few in the market. For example, 3,3',4,4'-biphenyl tetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA)-type (UPILEX-S type) polyimides show exceptional thermal stability (Tg up to ≈400 °C) and mechanical properties (tensile strength exceeding 500 MPa) and are the first choice if extremely high temperatures of 400 °C or even higher (depending on the duration) are required, which hampers their processing using existing 3D printing techniques. However, their processing using existing 3D printing techniques is hampered due to their thermal resistance. Herein, a 3D printing approach was demonstrated for generating complex lightweight BPDA-PDA polyimide geometries with unprecedented specific strength and thermal resistance. The simple aqueous polymerization reaction of BPDA with water-soluble PDA and triethylamine (TEA) afforded the poly(amic acid) ammonium salt (PAAS) hydrogels. These PAAS solutions showed clear shear thinning and thermo-reversibility, along with high G' gel-state moduli, which ensured self-supporting features and shape fidelity in the gel state. Postprinting thermal treatment transformed the PAAS precursor to BPDA-PDA polyimide (UPILEX-S type). The resulting layer-by-layer deposition onto lightweight polyimide honeycombs in the form of triangular, square, and hexagonal structures showed tailorable mechanical strength, exceptional compressive strength-to-weight ratio (highest up to 0.127 MPa (kg m-3)-1), and remarkable thermoresistance (Tg approximately 380 °C). These high-performance 3D printed polyimide honeycombs and unique synthetic techniques with general structures are potentially useful in fields ranging from automotive to aerospace technologies.

7.
PLoS Pathog ; 17(3): e1009393, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33684175

RESUMO

Classical swine fever virus (CSFV) is an important pathogen in the swine industry. Virion attachment is mediated by envelope proteins Erns and E2, and E2 is indispensable. Using a pull-down assay with soluble E2 as the bait, we demonstrated that ADAM17, a disintegrin and metalloproteinase 17, is essential for CSFV entry. Loss of ADAM17 in a permissive cell line eliminated E2 binding and viral entry, but compensation with pig ADAM17 cDNA completely rescued these phenotypes. Similarly, ADAM17 silencing in primary porcine fibroblasts significantly impaired virus infection. In addition, human and mouse ADAM17, which is highly homologous to pig ADAM17, also mediated CSFV entry. The metalloproteinase domain of ADAM17 bound directly to E2 protein in a zinc-dependent manner. A surface exposed region within this domain was mapped and shown to be critical for CSFV entry. These findings clearly demonstrate that ADAM17 serves as an essential attachment factor for CSFV.

8.
Neuroreport ; 32(6): 465-471, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33657075

RESUMO

Bipolar disorder is a manifestation of an emotional disease and is associated with emotional and cognitive dysfunction. The entropy-based method has been widely used to study the complexity of resting-state functional MRI (rs-fMRI) signals in mental diseases; however, alterations in the brain rs-fMRI signal complexities in bipolar disorder patients remain unclear, and previously used entropy methods are sensitive to noise. Here, we performed a work using permutation fuzzy entropy (PFEN), which has better performance than previously used methods, to analyze the brain complexity of bipolar disorder patients. Based on PFEN research, we obtained brain entropy maps of 49 bipolar disorder patients and 49 normal control, extracted the regions of interest to analyze the complexity of abnormal brain regions and further analyzed the correlation between the PFEN values of abnormal brain regions and the clinical measurement scores. Compared with the values in the normal control group, we found that significantly increased PFEN values mainly appeared in the middle temporal gyrus, angular gyrus, superior occipital gyrus and medial superior frontal gyrus, and the decreased PFEN values were found in the inferior temporal gyrus in bipolar disorder patients. In addition, the PFEN values of the angular gyrus was significantly negatively correlated with clinical scores. These findings improve our understanding of the pathophysiology of bipolar disorder patients.

9.
Chemosphere ; 276: 130090, 2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33740651

RESUMO

In this study, 4 Lactobacillus plantarum strains and 5 Lactobacillus fermentum strains adapting well to the unfavorable fruit system were isolated under different fruit environments. The fermentation ability of these autochthonous lactic acid bacteria (LAB) strains in blueberry juice, and the influence of microbial metabolism on juice composition were explored. After 48 h of fermentation, the viable cell counts exceeded 10.0 log CFU/mL, malic acid content decreased from 511.47 ± 10.50 mg/L to below 146.38 ± 3.79 mg/L, and lactic acid content increased from 0 mg/L to above 2184.90 ± 335.80 mg/L. Moreover, the metabolism of these strains exerted a profound influence on the phenolic composition of juice. Total phenolic content in blueberry juice increased by 6.1-81.2% under lactic acid fermentation, and the antioxidant capacity in vitro enhanced by at least 34.0%. Anthocyanin content showed a declining trend, while the profile of non-anthocyaninic phenolics exhibited complex changes. The increments of rutin, myricetin and gallic acid contents through 48 h lactic acid fermentation exceeded 136%, 71% and 38%, respectively. Instead, the contents of p-hydroxybenzoic acid and caffeic acid decreased with fermentation. Overall, Lactobacillus plantarum LSJ-TY-HYB-T9 and LSJ-TY-HYB-T7, and Lactobacillus fermentum LSJ-TY-HYB-C22 and LSJ-TY-HYB-L16 could be the suitable strains to produce fermented fruit juices, including blueberry in practical applications.

10.
Sci Total Environ ; 779: 146197, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33744586

RESUMO

With increasingly serious environmental pollution problems, research has focused on identifying functional genes within plants that can help ensure food security and soil governance. In particular, plants seem to have been able to evolve specific functional genes to respond to environmental changes by losing partial gene functions, thereby representing a novel adaptation mechanism. Herein, a new category of functional genes was identified and investigated, providing new directions for understanding heavy metal detoxification mechanisms. Interestingly, this category of proteins appears to exhibit specific complexing functions for heavy metals. Further, a new approach was established to evaluate ATP-binding cassette (ABC) transporter family functions using microRNA targeted inhibition. Moreover, mutant and functional genes were identified for future research targets. Expression profiling under five heavy metal stress treatments provided an important framework to further study defense responses of plants to metal exposure. In conclusion, the new insights identified here provide a theoretical basis and reference to better understand the mechanisms of heavy metal tolerance in potato plants. Further, these new data provide additional directions and foundations for mining gene resources for heavy metal tolerance genes to improve safe, green crop production and plant treatment of heavy metal soil pollution.

11.
Ultrason Sonochem ; 73: 105486, 2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-33639530

RESUMO

In this work, low-intensity ultrasonication (58.3 and 93.6 W/L) was performed at lag, logarithmic and stationary growth phases of Lactobacillus plantarum in apple juice fermentation, separately. Microbial responses to sonication, including microbial growth, profiles of organic acids profile, amino acids, phenolics, and antioxidant capacity, were examined. The results revealed that obvious responses were made by Lactobacillus plantarum to ultrasonication at lag and logarithmic phases, whereas sonication at stationary phase had a negligible impact. Sonication at lag and logarithmic phases promoted microbial growth and intensified biotransformation of malic acid to lactic acid. For example, after sonication at lag phase for 0.5 h, microbial count and lactic acid content in the ultrasound-treated samples at 58.3 W/L reached 7.91 ± 0.01 Log CFU/mL and 133.70 ± 7.39 mg/L, which were significantly higher than that in the non-sonicated samples. However, the ultrasonic effect on microbial growth and metabolism of organic acids attenuated with fermentation. Moreover, ultrasonication at lag and logarithmic phases had complex influences on the metabolism of apple phenolics such as chlorogenic acid, caffeic acid, procyanidin B2, catechin and gallic acid. Ultrasound could positively affect the hydrolysis of chlorogenic acid to caffeic acid, the transformation of procyanidin B2 and decarboxylation of gallic acid. The metabolism of organic acids and free amino acids in the sonicated samples was statistically correlated with phenolic metabolism, implying that ultrasound may benefit phenolic derivation by improving the microbial metabolism of organic acids and amino acids.

12.
Environ Sci Technol ; 55(4): 2307-2315, 2021 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-33539083

RESUMO

An investigation was conducted by determining artificial sweeteners (ASs) in 80 samples from various environmental matrices, including dry deposition, rainfall, soil, leaf, and bark samples around a pig farm in Tianjin, China. Saccharin, cyclamate, and acesulfame were predominant in dry deposition and rainfall samples. Spatially, the distribution of ASs showed a consistent trend of farm center > downwind sites > upwind sites > reference site. The annual total mass loads of saccharin (70%), cyclamate (25%), and acesulfame (5%) via dry deposition and precipitation within a 5 km radius of the pig farm were estimated at 3.9 and 6.2 kg in the average-case and worst-case scenarios, respectively, accounting for 12-18% of the overall emission, indicating that pig farms are a significant source of ASs to the atmosphere and to the vicinal environment via dry and wet deposition. The distribution trends of ASs in tree bark and leaves were similar and tree bark performed better in passively biomonitoring the AS contamination. Overall, pig farms were predicted to release 65-114, 22-38, 2.0-3.5, and 0.6-1.1 tons by feed application in China, Europe, Latin America, and North America, respectively, to the vicinal environment via dry deposition and precipitation.

13.
Artigo em Inglês | MEDLINE | ID: mdl-33522787

RESUMO

The large-area preparation of excellent lubricating materials with good resistance to leakage and an oxidation atmosphere and ease of replenishment has remained a challenge. Here, inspired by the Nepenthes pitcher slippery surface, we have fabricated multifunctional lubricant-infused surfaces (LISs) via a scalable technique, in which the solid lubricants and the lubricant oil are reciprocally well-combined to overcome their respective weakness. The designed LIS coating exhibits a multiple lubrication ability with a coefficient of friction of 0.022 and ball wear rate of 2.62 × 10-18 m3·N-1·m-1 in air, which are 21 times and three orders of magnitude lower than those of the steel-steel contact under macroscale test conditions (10 N, 5 Hz), respectively. In addition, the outstanding water-repellent and self-cleaning LIS coating enables the resistance to the strong acid or base corrosion even after 30 days of immersion, and the excellent anticorrosion performance during the electrochemical corrosion test. With the exceptional lubrication, multifunctionality performance, and large-scale fabrication capacity, the prepared LIS coating should find potential applications in machines, pipelines, navigation, infrastructures, outdoor equipment, and so on.

14.
Spectrochim Acta A Mol Biomol Spectrosc ; 252: 119498, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-33581577

RESUMO

Porous coordination polymers with organic aminium as one of the guest species possess a potential application in dye adsorption and white-light material manufacture. Polycarboxylic acid with multiple COOH substituents tends to form this type of porous material (with metal ion). Here the solvothermal self-assembly between Cd2+ and a hexacarboxylic acid creates such a porous material [(CH3)2NH2]6[Cd3(L)2]·5DMF·3H2O (H6L = 3,4-di(3,5-dicarboxyphenyl)phthalic acid) 1. Total potential guest accessible void volume in 3-D 1 is found to be 4327 Å3. Based on its better porous structure and stability, the ability of 1 to adsorb organic dyes is investigated. It has been proved that (i) 1 can selectively adsorb cationic dyes as Azure A (AA+) and/or Methylene Blue (MB+), rather than neutral and anionic ones; (ii) the maximum adsorption capacity is 698.2 mg·g-1 for AA+ and 573.2 mg·g-1 for MB+, respectively; and (iii) to the adsorption of AA+, it can be recycled for at least five rounds. Also, it is utilized to fabricate the while-light emitting material. Based on the blue-light emission of 1, the trace Eu3+ and Tb3+ ions are introduced into the pores of 1 successfully, obtaining a white-light emitting material Eu3+/Tb3+@1 (CIE chromaticity coordinates: (0.33, 0.32)). Meanwhile, Eu3+/Tb3+@1 is found to be a potential fluorescence photochromic material, showing a yellow-white-blue light emission. According to these investigations, the relationship between material structure and its adsorption property for dyes, the points that should be paid attention to in the construction of white-light emitting materials as well as the potential adsorption mechanism for dyes and rare earth ions are deeply discussed.

16.
Clin Ther ; 2021 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-33637331

RESUMO

PURPOSE: Antihypertensive agents are frequently prescribed in kidney transplant recipients (KTRs). However, the frequency and patterns of prescribing antihypertensive agents remain uncharacterized in KTRs in China. Therefore, this investigation was carried out. METHODS: Retrospective prescription data dated 2011 to 2018 from KTRs in China were accessed using the Hospital Prescription Analysis Program database. Information about sex, birth date, and identification number of the patient; city, date, and department of the medical visit; major diagnoses; and the generic names, specifications, quantities, and usage of prescribed drugs were collected. Antihypertensive agents were grouped into 5 classes: angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), ß-blockers (BBs), calcium channel blockers (CCBs), and diuretics. The frequency and patterns of prescribing these antihypertensive agents were analyzed. FINDINGS: Prescriptions from 174,749 KTRs (67.2% male; mean age, 42.5 [9.4] years) were obtained, and 58.2% of the patients were prescribed antihypertensive agents. The percentage of patients who received antihypertensive treatment increased from 52.9% in 2011 to 61.6% in 2018 and varied by city. Cyclosporine was associated with higher prescription frequency of antihypertensive agents than was tacrolimus (71.7% vs 63.4%; P < 0.0001). During the 8-year study period, CCBs were most frequently prescribed (39.0%), followed by ARBs (31.9%), BBs (14.3%), ACEIs (11.6%), and diuretics (3.2%). The mean (SD) number of antihypertensive drugs prescribed per KTR was 1.7 (0.8). Almost half of KTRs (51.2%) received just 1 antihypertensive drug. Co-administration of 2 or more antihypertensive drugs presented an obviously upward trend. The most commonly prescribed 2-drug combination was CCB + ARB (44.8%), followed by CCB + BB (20.1%) and CCB + ACEI (13.0%). In the patients who received 3 antihypertensive drugs, the 2 most frequently prescribed combinations were CCB + ARB + BB (37.5%) and CCB + ARB + ACEI (32.7%). Specific data varied by both year and city. IMPLICATIONS: The prescribing patterns of antihypertensive agents in KTRs varied by city even within same country. Hence, more high-quality research studies on the use of antihypertensive agents in KTRs are needed.

17.
ACS Appl Mater Interfaces ; 13(8): 9739-9747, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33617221

RESUMO

The exploitation of effective strategies to develop materials bearing deep tissue focal fluorescence imaging capacity and excellent reactive oxygen species (ROS) generation ability is of great interest to address the high-priority demand of photodynamic therapy (PDT). Therefore, we use a rational strategy to fabricate a two-photon-active metal-organic framework via a click reaction (PCN-58-Ps). Moreover, PCN-58-Ps is capped with hyaluronic acid through coordination to obtain cancer cell-specific targeting properties. As a result, the optimized composite PCN-58-Ps-HA exhibits considerable two-photon activity (upon laser excitation at a wavelength of 910 nm) and excellent light-triggered ROS (1O2 and O2•-) generation ability. In summary, the interplay of these two critical factors within the PCN-58-Ps-HA framework gives rise to near-infrared light-activated two-photon PDT for deep tissue cancer imaging and treatment, which has great potential for future clinical applications.

18.
Water Sci Technol ; 83(3): 739-750, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33600376

RESUMO

Application of sewage sludge biochar as an adsorbent for antibiotics treatment has obtained special attention owning to its low cost and surface functionality. Three metal ions were selected to modify sewage sludge biochar through the pyrolysis with the metal loaded method. Fe loaded sewage sludge biochar (BC-Fe), Al loaded sewage sludge biochar (BC-Al) and Mn loaded sewage sludge biochar (BC-Mn) were characterized and used to explore the performance of adsorbing tetracycline (TC), sulfamethoxazole (SMZ) and amoxicillin (AMC). BC-Fe, BC-Al and BC-Mn possessed rougher surfaces, larger specific surface area and better pore structure. Intra-particle diffusion and Langmuir models were more suitable to describe the adsorption process. The maximum adsorption amount of TC, SMZ and AMC could reach 123.35, 99.01 and 109.89 mg/g by BC-Fe. Furthermore, the main mechanism of antibiotics adsorption by metal loaded sewage sludge biochars might be pores filling, Van der Waals forces and H-bonding. The study can not only solve the problems associated with the pollution of antibiotics from wastewater, but also reduced the treatment pressure of sewage sludge effectively.


Assuntos
Antibacterianos , Esgotos , Adsorção , Carvão Vegetal , Água
19.
J Magn Reson Imaging ; 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33576137

RESUMO

BACKGROUND: Schizophrenia (SC) and bipolar disorder (BP) share elements of symptoms and the underlying neural mechanisms for both remain unclear. Recently, the complexity of spontaneous functional MRI (fMRI) signals in brain activity has been investigated in SC and BP using multiscale sample entropy (MSE) with inconsistent results. PURPOSE: To perform MSE analysis across five time scales to assess differences in resting-state fMRI signal complexity in SC, BP, and normal controls (NC). STUDY TYPE: Retrospective. POPULATION: Fifty SC, 49 BP, and 49 NC. FIELD STRENGTH/SEQUENCE: A 3 T, T2* weighted echo planar imaging (EPI) sequence. ASSESSMENT: The mean MSEs of all gray matter (GM) and of 12 regions of interest (ROIs) were extracted using masks across the five scales. The regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) in these ROIs were also determined and the relationship between the three measures was investigated. The correlations between cognitive assessment scores and MSE values were also explored. STATISTICAL TESTS: Bonferroni correction, One-way ANOVA, Spearman rank correlation coefficient (r), Gaussian random field (GRF) correction. RESULTS: There were decreased GM MSE values in the patient groups (F = 9.629, P < 0.05). SC and BP patients demonstrated lower complexity than NCs in the calcarine fissure, precuneus, inferior occipital gyrus, lingual gyrus and cerebellum, and higher complexity in the median cingulate, thalamus, hippocampus, middle temporal gyrus and middle frontal gyrus. There were significant differences between SC and BP patients in the precuneus (F = 4.890, P < 0.05) and inferior occipital gyrus (F = 5.820, P < 0.05). Calcarine fissure, cingulate, temporal gyrus, occipital gyrus, hippocampus, precuneus, frontal gyrus, and lingual gyrus MSE values were significantly correlated with both ReHo (r > 0.282, P < 0.05) and ALFF (r > 0.278, P < 0.05). Furthermore, median temporal MSE (r = -0.321, P < 0.05) on scale 3 and (r = -0.307, P < 0.05) on scale 4 and median cingulate MSE (r = -0.337, P < 0.05) on scale 5 was significantly negatively correlated with cognitive assessment scores. DATA CONCLUSION: These data highlight different patterns of brain signal intensity complexity in SC and BP. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 1.

20.
J Agric Food Chem ; 69(6): 1852-1863, 2021 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-33550805

RESUMO

Stevia (Stevia rebaudiana Bertoni) possesses substantial value for its unique sweet compounds-steviol glycosides (SGs). In the metabolic glycosylation grid of SGs, SrUGT91D2 has been shown to catalyze formation of 1,2-ß-d-glucoside linkages at the C13- and C19-positions and play a crucial role in the synthesis of SGs, including the formation of stevioside (ST), rebaudioside E (RE), and rebaudioside D (RD). However, the key residues of the SrUGT91D2 enzyme and how SrUGT91D2 affects the accumulation of SGs in S. rebaudiana remain unclear. In the present study, cloning and functional analysis of full-length SrUGT91D2 gene sequences were performed in 10 different S. rebaudiana genotypes with divergent SG compositions. After sequence analysis, it was found that most of the sequences of this gene (more than 50%) in each genotype were consistent with the UGT91D2e_No.5 allele, which has been reported to exert catalytic activity on 1,2-ß-d-glucoside. Moreover, six variants (UGT91D2e_No.5, SrUGT91D2-11-14, SrUGT91D2-110, SrUGT91D2-023, SrUGT91D2-N01, and SrUGT91D2-N04) of this gene were obtained, and their activities were identified. Although there were some differences among these variants, the only type of mutation was partial base substitution at a very low level. In addition, the expression analysis of SrUGT91D2 in each genotype showed that the expression level of the gene was significantly different among genotypes, and a significant positive correlation was found between the content of RD (which was closely influenced by SrUGT91D2) and the expression level of SrUGT91D2 in each genotype (correlation coefficient = 0.91). Thus, it was indicated that SrUGT91D2 was relatively conserved in S. rebaudiana, and the differential effect of SrUGT91D2 on the accumulation of related SGs mainly derived from its expression level. Furthermore, based on homologous modeling and molecular docking analysis, T84, T144, A194, S284, E285, V286, G365, E369, R404, and G409 were predicted to be key residues in the glucosylation of SGs by SrUGT91D2. After site-mutation and enzyme assays, it was confirmed that T84, T144, R404, A194, and G409 are the key residues in the SrUGT91D2 protein, especially T144 and G409. This work provided valuable information for understanding the structure-activity relationship of the SrUGT91D2 protein and the molecular mechanism of SG accumulation in stevia.

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