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1.
Sci Rep ; 14(1): 25448, 2024 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-39455808

RESUMO

The emergence of nanogenerators, which have the ability to capture mechanical energy from the environment and to collect and transmit tiny energy, is rapidly becoming a hot research topic. The performance of electrode materials is the key to the efficiency of nanogenerators. Covalent organic skeletons (COFs), a class of crystalline organic porous materials with the advantages of large specific surface area, high porosity, tunable structure, and flexible tailorability, have very significant advantages in being used as nanogenerator materials. In this paper, we synthesised two COF materials to investigate the effect of the introduction of active metals on the friction power generation performance of COFs without changing their topology, COF-2 containing zinc ions is capable of generating a short-circuit current of 107.5 µA during friction. The porous structure increases the effective contact area to form a larger charge density, and the introduction of metal ions can accelerate the charge separation and transport. The two bidirectional synergistic effects of the materials significantly improve the output performance of the nanogenerator, and a simple and efficient method is explored for the enhancement of the output performance of COF-based triboelectric nanogenerators.

2.
Mycology ; 15(2): 210-237, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38813475

RESUMO

Russula is the largest genus in the Russulales and is widespread throughout the world. Almost all Russula species are known to be ectomycorrhizal with high ecological and edible values, and some are lethal poisonous. In this study, four new species belonging to the subgenus Russula crown clade are identified based on morphological and phylogenetic evidence from the Xizang Autonomous Region and other provinces of China. Morphologically, Russula paragraveolens (sect. Polychromae, subsect. Xerampelinae) is mainly characterised by a cherry red to blood red pileus centre, a reddish orange pileus margin; R. pseudograveolens (sect. Polychromae, subsect. Xerampelinae) is characterised by a violet brown to brownish red pileus centre, a pale red to pastel red pileus margin and short basidia; R. shigatseensis (sect. Flavisiccantes, subsect. Lepidinae) is characterised by a brownish orange to madder red pileus centre, pinkish red pileus margin, and having lateral branches or branches of hyphal terminations in pileipellis; R. yadongensis (sect. Tenellae, subsect. Laricinae) is characterised by a dark purplish red pileus centre with brownish purple tints and having isolated to clustered spines of spore ornamentations. Their distinct taxonomic status is confirmed by the positions of the four new species in both the ITS and 4-locus (nucLSU, mtSSU, rpb2, tef1) phylogenetic trees.

3.
Zhongguo Gu Shang ; 37(4): 392-8, 2024 Apr 25.
Artigo em Chinês | MEDLINE | ID: mdl-38664211

RESUMO

OBJECTIVE: To evaluate the rabbit modle of frozen shoulder induced by persistent strain injuries and ice compression. METHODS: Twelve clean, healthy male New Zealand rabbits with a mass of (2 500±500) g were selected and randomly divided into a blank group and a control group with 6 rabbits in each group. In the control group, the rabbits were modeled with persistent strain injuries and ice compression, the general conditions of the rabbits and the active and passive activities of the shoulder joint were observed and their body weights were recorded. MRI was performed on the affected shoulder joints at 6 d and 29 d after modelling to observe the fluid and soft tissue;HE staining was used to observe the morphology of the rabbit biceps longus tendon and the synovial membrane of the joint capsule;Masson staining was used to observe the fibrous deposits of the rabbit biceps longus tendon and the synovial membrane of the joint capsule, and the fibrous deposits were analysed semi-quantitatively by Image J software. RESULTS: Six days after the end of modeling, the active movement of the shoulder joints in the control group was limited, the passive movement was not significantly limited, and they walked with a limp;29 days after the end of the modeling, the active and passive movements of the shoulder joints in the model group were severely limited. Compared with the blank group (2.50±0.14) kg, the body weight of the model group (2.20±0.17) kg was significantly reduced(P<0.01). MRI showed that 6 days after modelling, the muscles around the shoulder joint were not smooth in shape, the joint capsule structure was narrowed and a large amount of fluid was seen in the joint cavity;29 days after modelling, the muscles around the shoulder joint were rough in shape, structure of the joint capsule was unclear and the fluid in the joint cavity was reduced compared with 6 days after modelling. Pathological staining showed that the long-headed biceps tendon fibres in the control group were disorganised, curled or even broken, and the synovial tissue of the joint capsule was heavily vascularised, with collagen fibre deposits and severe inflammatory cell infiltration. The fiber deposition of the long head of biceps brachii in the model group [(23.58±3.41)%, (27.56±3.70)%] and synovial tissue [(41.78±5.59)%, (62.19±7.54)%] were significantly higher than those in the blank group [(1.79±1.03) %, (1.29±0.63) %] at 7 and 30 days after modeling and synovial tissue fiber deposition [(8.15±3.61) %, (11.29±7.10) %], as shown by the semi-quantitative analysis of Masson staining results by Image J software. And the longer the time, the more severe the fibrosis (P<0.01). CONCLUSION: The behavioral, imaging and pathological findings showed that the rabbit frozen shoulder model with persistent strain injuries and ice compression is consistent with the clinical manifestations and pathogenesis of periarthritis, making it an ideal method for periarthritis research.


Assuntos
Bursite , Modelos Animais de Doenças , Animais , Coelhos , Masculino , Bursite/fisiopatologia , Gelo , Entorses e Distensões/fisiopatologia , Articulação do Ombro/fisiopatologia , Imageamento por Ressonância Magnética
4.
J Fungi (Basel) ; 10(3)2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38535228

RESUMO

The species of Gymnopilus (Hymenogastraceae, Agricales) are commonly recognized as wood-decaying fungi. Certain members of this genus have been identified as psilocybin-producing mushrooms. Gymnopilus exhibits a diverse range and has a global distribution. In this study, a total of seventy-eight specimens were gathered from ten provinces in China. A comprehensive molecular phylogenetic analysis was conducted, employing gene sequences including ITS, nrLSU, nrSSU, rpb1, rpb2, and tef1-α. Additionally, morphological examinations were also carried out. The phylogenetic topology of Gymnopilus from this study generally agreed with previous studies and facilitated the identification of all those specimens. As a result, eleven species, including five newly discovered ones named Gy. gyirongensis, Gy. variisporus, Gy. tomentosiceps, Gy. tenuibasidialis, and Gy. aurantipileatus, were recognized. Significantly, four of the five newly identified species are native to the Xizang Autonomous Region, emphasizing their specialization in this distinctive habitat. This research contributes to our comprehension of Gymnopilus diversity and lays the groundwork for the conservation and sustainable utilization of Gymnopilus resources.

5.
PeerJ ; 12: e16721, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38250726

RESUMO

Wild plants represent a potential source of urban landscape trees. Stranvaesia davidiana Dcne. is a member of the Stranvaesia Lindl. Genus, which belongs to family Rosaceae Juss. It has great ornamental value. It can contribute to urban color foliage and fruit species. However, the most effective fertilizer application strategy required for its cultivation is unknown. Therefore, we conducted an orthogonal experiment to investigate the fertilizer type and level (pure nitrogen) using ten experimental groups, including an untreated control group. Pot experiments were used to determine the growth indices of seedlings, including plant height, basal diameter, and chlorophyll content post-fertilizer treatment. This study explored the most appropriate fertiler application model for the growth of S. davidiana seedlings. The results revealed that enhanced seedling growth depended on the type and amount of fertilizer used, and their interaction. Fertilizer application increased the plant height by 2.67 cm to 12.26 cm, basal diameter by 0.39 cm to 0.75 cm, and chlorophyll content by 5.66 to 19.86. Among the different types of fertilizer, organic fertilizer increased the plant height by 0.42 cm to 9.59 cm and basal diameter by 0.01 cm to 0.05 cm, compared with the control group. Organic fertilizer had the maximum effect on seedling growth, especially at medium levels. The total growth of basal diameter and chlorophyll content was 1.58 ± 0.04 cm and 39.53 ± 2.37, respectively. Basal diameter is the most critical index in seedling reproduction . The study results suggest that the application of 4.06 g of organic fertilizer per plant was the most effective, and served as a basis for further field trials.


Assuntos
Rosaceae , Plântula , Fertilizantes , Clorofila , Grupos Controle
6.
Molecules ; 28(23)2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-38067625

RESUMO

MOF (metal organic framework) materials have been used as functional materials in a number of fields due to their diverse spatial tunability, which produces rich porous structures with stable and continuous pores and a high specific surface area. A triboelectric nanogenerator can convert trace mechanical energy into electrical energy, and the application of MOF materials to triboelectric nanogenerators has been intensively studied. In this work, we report on two MOFs with similar spatial structures, and the modulation of the end microstructures was achieved using the difference in F content. The output performance of friction power generation increases with the increase in F content, and the obtained polyacidic ligand materials can be used to construct self-powered corrosion protection systems, which can effectively protect metallic materials from corrosion.

7.
RSC Adv ; 13(40): 28224-28229, 2023 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-37767118

RESUMO

The emergence of nanogenerators, which provide a way to obtain mechanical energy from the environment and to collect and transmit tiny amounts of energy, has attracted a lot of attention. MOFs, because of their diverse structures as well as stable pores and large specific surface area, have very significant advantages to be used as nanogenerator materials. In this paper, two MOFs with similar spatial structures are designed to take advantage of the different coordination numbers of carboxylic acids to achieve the regulation of their microstructures. The output performance of friction power generation was found to be affected significantly by their microstructures. The friction power generation performance improved with the increase of carboxylic acids, and the obtained polyacid ligand materials can be used for light bulb illumination, which is a step forward for the practical exploration.

8.
JPRAS Open ; 37: 109-120, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37520027

RESUMO

Background: In microsurgical tissue transfer, skin flap transplantation is frequently used to heal the surface of a wound. Effective microcirculation surveillance of the skin flap is crucial. However, with traditional monitoring methods-that is, clinical observation-vascular crisis can still occur, thereby impairing postoperative recovery. A smartphone application is required to assist health care professionals in the standardized collection of flap perfusion parameters for flap management. Methods: The Vascular Crisis Prewarning Application was created using a design science research methodology that prioritizes users and problems. The system usability scale was used to assess the application's usability among medical practitioners. The application was used at the clinic from December 2020 to September 2022. The unplanned return to the operating room, time to diagnose vascular crisis, and flap survival rate were compared with and without the application. Results: The application consisted of 5 modules: patient addition and basic information entry, flap labeling, flap observation, crisis warning, and case archiving. The average rating for the application's usability among medical practitioners was 97.95 score (SD 2.36). With the application, the time to detect vascular crisis reduced from 26.71 to 16.26 h (P < 0.001), the unplanned return to the operation room increased from 8.18% to 10.24% (P = 0.587), and the flap survival rate went from 94.55% to 99.21% (P = 0.083). Conclusions: An easy-to-use flap perfusion monitoring and prewarning application for medical practitioners was produced using a user-centered development method. The application provided a more standardized and accurate platform for data collection in flap management and reduced the time to detect vascular crisis. Larger cohort studies are required in the future to better assess the full potential of the application.

9.
Bioact Mater ; 28: 206-226, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37274446

RESUMO

Human pluripotent stem cell-derived cardiovascular progenitor cells (hCVPCs) and cardiomyocytes (hCMs) possess therapeutic potential for infarcted hearts; however, their efficacy needs to be enhanced. Here we tested the hypotheses that the combination of decellularized porcine small intestinal submucosal extracellular matrix (SIS-ECM) with hCVPCs, hCMs, or dual of them (Mix, 1:1) could provide better therapeutic effects than the SIS alone, and dual hCVPCs with hCMs would exert synergic effects in cardiac repair. The data showed that the SIS patch well supported the growth of hCVPCs and hCMs. Epicardially implanted SIS-hCVPC, SIS-hCM, or SIS-Mix patches at 7-day post-myocardial infarction significantly ameliorated functional worsening, ventricular dilation and scar formation at 28- and 90-day post-implantation in C57/B6 mice, whereas the SIS only mildly improved function at 90-day post-implantation. Moreover, the SIS and SIS-cell patches improved vascularization and suppressed MI-induced cardiomyocyte hypertrophy and expression of Col1 and Col3, but only the SIS-hCM and the SIS-Mix patches increased the ratio of collagen III/I fibers in the infarcted hearts. Further, the SIS-cell patches stimulated cardiomyocyte proliferation via paracrine action. Notably, the SIS-Mix had better improvements in cardiac function and structure, engraftments, and cardiomyocyte proliferation. Proteomic analysis showed distinct biological functions of exclusive proteins secreted from hCVPCs and hCMs, and more exclusive proteins secreted from co-cultivated hCVPCs and hCMs than mono-cells involving in various functional processes essential for infarct repair. These findings are the first to demonstrate the efficacy and mechanisms of mono- and dual-hCVPC- and hCM-seeding SIS-ECM for repair of infarcted hearts based on the side-by-side comparison.

10.
J Fungi (Basel) ; 9(3)2023 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-36983498

RESUMO

The enoki mushroom (Flammulina filiformis) is one of the most important and popular edible mushrooms commercially in China. However, traditional mushroom cultivar identification is challenging due to poor accuracy, heavy workloads, and low reproducibility. To overcome this challenge, we developed a method for identifying F. filiformis strains using multiple nucleotide polymorphism sequencing (MNP-seq). This involved screening 179 universal MNP markers based on whole-genome sequencing data, constructing an MNP sequence library, and performing multiplex PCR amplification and high-sequencing. We further screened 69 core MNP markers and used them to build a neighbor-joining (NJ) phylogenetic tree of 232 cultivated and wild strains. Our analysis showed that all cultivars could be accurately separated by computing genetic similarity values and that the cultivars could be separated into 22 distinct evolutionary pedigrees. The specific value of genetic similarity can be used as the standard to distinguish F. filiformis cultivars, however, it needs to be comprehensively defined by the additional phenotype and biological characteristics of those strains in the future work.

11.
Nat Prod Res ; 36(21): 5449-5454, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34903137

RESUMO

Three new compounds, polygalapyrone A (1), tenuiside G (2) and polygalapyrrole A (3), together with two known compounds (4-5) were isolated by silica gel, ODS and preparative HPLC from the aerial part of Polygala tenuifolia. Their structures were elucidated by spectrum analysis and compared with findings from the literature. The anti-inflammatory effects of those compounds were investigated in vitro.


Assuntos
Polygala , Polygala/química , Cromatografia Líquida de Alta Pressão , Componentes Aéreos da Planta
12.
Artigo em Inglês | MEDLINE | ID: mdl-33204295

RESUMO

BACKGROUND: Diabetic retinopathy (DR) includes a series of typical lesions affected by retinal microvascular damage caused by diabetes mellitus (DM), which not only seriously damages the vision, affecting the life's quality of patients, but also brings a considerable burden to the family and society. Astragalus Membranaceus (AM) is a commonly used medicine in clinical therapy of eye disorders in traditional Chinese medicine (TCM). In recent years, it is also used for treating DR, but the specific mechanism is unclear. Therefore, this study explores the potential mechanism of AM in DR treatment by using network pharmacology. METHODS: Based on the oral bioavailability (OB) and drug likeness (DL) of two ADME (absorption, distribution, metabolism, excretion) parameters, Traditional Chinese Medicine Systems Pharmacology Database (TCMSP), Swiss Target Prediction platform, GeneCards, and OMIM database were used to predict and screen the active compounds of AM, the core targets of AM in DR treatment. The Metascape data platform was used to perform Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis on the core targets. RESULTS: 24 active compounds were obtained, such as quercetin, kaempferol, and astragaloside IV. There were 169 effective targets of AM in DR treatment, and the targets were further screened and finally, 38 core targets were obtained, such as VEGFA, AKT1, and IL-6. EGFR tyrosine kinase inhibitor resistance, AGE-RAGE signaling pathway in diabetic complications, PI3K-Akt signaling pathway, and other metabolic pathways participated in oxidative stress, cell apoptosis, angiogenesis signal transduction, inflammation, and other biological processes. CONCLUSION: AM treats DR through multiple compounds, multiple targets, and multiple pathways. AM may play a role in the treatment of DR by targeting VEGFA, AKT1, and IL-6 and participating in oxidative stress, angiogenesis, and inflammation.

13.
Chin Herb Med ; 12(3): 257-264, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36119014

RESUMO

Objective: Fusarium oxysporum is a common pathogenic fungus in ginseng cultivation. Both pathogens and antagonistic fungi have been reported to induce plant resistance responses, thereby promoting the accumulation of secondary metabolites. The purpose of this experiment is to compare the advantages of one of the two fungi, in order to screen out more effective elicitors. The mechanism of fungal elicitor-induced plant resistance response is supplemented. Methods: A gradient dilution and the dural culture were carried out to screen strains. The test strain was identified by morphology and 18 s rDNA. The effect of different concentrations (0, 50, 100, 200, 400 mg/L) of Penicillium sp. YJM-2013 and F. oxysporum on fresh weight and ginsenosides accumulation were tested. Signal molecules transduction, expression of transcription factors and functional genes were investigated to study the induction mechanism of fungal elicitors. Results: Antagonistic fungi of F. oxysporum was identified as Penicillium sp. YJM-2013, which reduced root biomass. The total ginsenosides content of Panax ginseng adventitious roots reached the maximum (48.95 ± 0.97 mg/g) treated with Penicillium sp. YJM-2013 at 200 mg/L, higher than control by 2.59-fold, in which protopanoxadiol-type ginsenosides (PPD) were increased by 4.57 times. Moreover, Penicillium sp. YJM-2013 activated defense signaling molecules, up-regulated the expression of PgWRKY 1, 2, 3, 5, 7, 9 and functional genes in ginsenosides synthesis. Conclusion: Compared with the pathogenic fungi F. oxysporum, antagonistic fungi Penicillium sp. YJM-2013 was more conducive to the accumulation of ginsenosides in P. ginseng adventitious roots. Penicillium sp. YJM-2013 promoted the accumulation of ginsenosides by intensifying the generation of signal molecules, activating the expression of transcription factors and functional genes.

14.
Gene ; 693: 101-113, 2019 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-30716435

RESUMO

Mitten crab (Eriocheir sensu stricto) is an indigenous and economically important species in East Asia. The genetic diversity and population structure of four wild native Eriocheir s. s. populations, from Yangtze (YZ), Oujiang (OJ), Minjiang (MJ), and Nanliujiang (NLJ) River basin, were studied. Genetic diversity of the four populations was evaluated by eight microsatellite and mitochondrial cytochrome oxidase subunits I (COI) markers. The polymorphism information content (PIC) values ranged from 0.7827 to 0.8580 and Shannon Wiener index (I) values varied from 2.0722 to 2.4088 respectively, according to microsatellite markers analysis. The haplotype diversity (h) values ranged from 0.52101 to 0.87097, while the values of nucleotide diversity (π) varied from 0.00139 to 0.02796 based on mitochondrial COI gene sequence. Four wild Eriocheir s. s. populations all showed high genetic diversity. As microsatellite analysis results, pair-wise FST values of YZ, OJ, MJ and NLJ populations were 0.1347, 0.1103 and 0.0943 respectively, which indicated that they were in medium genetic differentiation (0.05 < FST < 0.15). This was consistent with mitochondrial COI gene's conclusion. The bottleneck analysis was a hint that Eriocheir s. s. experienced bottleneck effect under SMM models of Sign Test and Wilcoxon Sign-rank Test. Based on genetic structure, YZ, OJ and MJ populations were in the same cluster separated from NLJ population. In summary, by microsatellite and mitochondrial COI markers analysis, all four Eriocheir s. s. populations had high genetic diversity, and genetic differentiation was consistent with geographical distance. Populations OJ and MJ were closer to population YZ genetically, and they had large genetic distance with NLJ population. This study provides a particularly important basis for mitten crab resources conservation and utilization in south China.


Assuntos
Braquiúros/genética , DNA Mitocondrial/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Animais , China , Genes Mitocondriais/genética , Variação Genética/genética , Genética Populacional/métodos , Haplótipos , Repetições de Microssatélites/genética , Filogenia , Polimorfismo Genético/genética , Análise de Sequência de DNA/métodos
15.
J Agric Food Chem ; 66(36): 9446-9455, 2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-30095259

RESUMO

Ginsenosides attract great attention for their bioactivities. However, their contents are low, and many UDP-glycosyltransferases (UGTs) that play crucial roles in the ginsenoside biosynthesis pathways have not been identified, which hinders the biosynthesis of ginsenosides. In this study, we reported that one UDP-glycosyltransferase, UGTPg71A29, from Panax ginseng could glycosylate C20-OH of Rh1 and transfer a glucose moiety to Rd, producing ginsenosides Rg1 and Rb1, respectively. Ectopic expression of UGTPg71A29 in Saccharomyces cerevisiae stably generated Rg1 and Rb1 under its corresponding substrate. Overexpression of UGTPg71A29 in transgenic cells of P. ginseng could significantly enhance the accumulation of Rg1 and Rb1, with their contents of 3.2- and 3.5-fold higher than those in the control, respectively. Homology modeling, molecular dynamics, and mutational analysis revealed the key catalytic site, Gln283, which provided insights into the catalytic mechanism of UGTPg71A29. These results not only provide an efficient enzymatic tool for the synthesis of glycosides but also help achieve large-scale industrial production of glycosides.


Assuntos
Ginsenosídeos/biossíntese , Glicosiltransferases/química , Glicosiltransferases/metabolismo , Panax/enzimologia , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Motivos de Aminoácidos , Vias Biossintéticas , Catálise , Domínio Catalítico , Glicosiltransferases/genética , Simulação de Dinâmica Molecular , Panax/química , Panax/genética , Proteínas de Plantas/genética , Difosfato de Uridina/metabolismo
16.
J Phys Chem B ; 116(20): 5803-9, 2012 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-22536844

RESUMO

(-)-Epigallocatechin-3-gallate (EGCG) has been proven effective in preventing the aggregation of amyloid ß-protein 42 (Aß42), and the thermodynamic interactions between Aß42 and EGCG have been studied in our previous work ( J. Phys. Chem. B 2010, 114, 11576). Herein, to further probe the interactions between different regions of Aß42 and EGCG, three Aß42 fragments (i.e., Aß1-16, Aß1-30, and Aß31-42) were synthesized, and the thermodynamic interactions between each of the fragments and EGCG at different EGCG and salt concentrations were investigated by isothermal titration calorimetry. The results indicate that, although hydrogen bonding and hydrophobic interaction are both involved in the interactions between Aß42 and EGCG, hydrogen bonding mainly happens in Aß1-16 while hydrophobic interaction mainly happens in Aß17-42. It is found that when Aß42 and its fragments are saturated by EGCG, their thermodynamic parameters have linear relationships. The saturated binding stoichiometry (N(s)) for Aß42 is the sum of the N(s) values for Aß1-30 and Aß31-42, while ΔH(s), ΔS(s), and ΔG(s) for Aß42 are half the sum of the values for Aß1-30 and Aß31-42. The result suggests that there are no specific interactions and binding sites in the Aß42 and EGCG binding. The orders of ΔH(s) and TΔS(s) values for the Aß fragments are determined as Aß17-42 > Aß31-42 > Aß1-30 > Aß1-16. Moreover, there is significant enthalpy-entropy compensation in the binding of EGCG to Aß42 and its fragments, resulting in insignificant change of ΔG with the change of the solution environment. The research has shed new light on the molecular mechanisms of the interactions between EGCG and Aß42.


Assuntos
Peptídeos beta-Amiloides/química , Catequina/análogos & derivados , Fragmentos de Peptídeos/química , Peptídeos beta-Amiloides/metabolismo , Calorimetria , Catequina/química , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Fragmentos de Peptídeos/metabolismo , Sais/química , Termodinâmica
17.
Int J Biol Macromol ; 50(5): 1229-37, 2012 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-22537475

RESUMO

The molecular interactions between EGCG and insulin were investigated to probe the mechanism of EGCG-induced insulin precipitation. The results indicated that 1-5mM EGCG induced insulin into reversible globular precipitates of 185-365 nm. The formation of precipitates was facilitated at high salt concentration and pH values close to insulin's isoelectric point, indicating that hydrophobic interaction was the main driving force. The precipitation was positively related to insulin concentration, but for EGCG, there was a suitable concentration (2 mM at 2 mg/mL of insulin) at which the precipitate content reached maximum. Mass spectroscopy analysis indicated that EGCG formed clusters in the aqueous solution and the clusters correlate with the insulin precipitation. Based on extensive investigation, a physical model was proposed to explain the molecular interactions between EGCG and insulin. Namely, EGCG monomers and clusters first bound to insulin dimers via hydrophobic interaction, leading to the reduction of the thickness of the hydration layer and the partial denaturation of insulin. Then, EGCG clusters acted as bridges to induce the aggregation and precipitation of insulin.


Assuntos
Catequina/análogos & derivados , Insulina/química , Catequina/química , Catequina/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Insulina/metabolismo , Cinética , Ligação Proteica , Sais/química , Solubilidade , Soluções/química
18.
J Phys Chem B ; 114(35): 11576-83, 2010 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-20718413

RESUMO

One of the key factors of Alzheimer's disease (AD) is the conversion of amyloid beta-peptide (Abeta) from its soluble random coil form into various aggregated forms. (-)-Epigallocatechin-3-gallate (EGCG) has been proved effective in preventing the aggregation of Abeta, but the thermodynamic mechanisms are still unclear. In this work, isothermal titration calorimetry (ITC) was utilized to study the interactions between Abeta42 and EGCG at different temperatures, salt concentrations, pH values, and EGCG and Abeta42 concentrations. Molecular dynamics (MD) simulations were performed to study the hydrogen bonding between Abeta42 and EGCG. The results indicate that the binding stoichiometry N is linearly related to the EGCG/Abeta42 ratio. Hydrophobic interaction and hydrogen bonding are both substantial in the binding process, but the extent of their contributions changes with experimental conditions. Namely, the predominant interaction gradually shifts from a hydrogen bonding to a hydrophobic interaction with the increase of the EGCG/Abeta42 ratio, resulting in a transition of the binding from enthalpy-driven to entropy-driven. This experimental observation is validated by the MD simulations. The binding of EGCG to Abeta42 can be promoted by increasing temperature and salt concentration and changing pH away from Abeta42's pI. The findings have provided new insight into the molecular interactions between Abeta42 and EGCG from a thermodynamic perspective and are expected to facilitate the research on the inhibition of Abeta42 aggregation.


Assuntos
Peptídeos beta-Amiloides/química , Catequina/análogos & derivados , Fragmentos de Peptídeos/química , Calorimetria , Catequina/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Simulação de Dinâmica Molecular , Concentração Osmolar , Ligação Proteica , Temperatura , Termodinâmica
19.
Zhong Yao Cai ; 29(2): 110-1, 2006 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-16617774

RESUMO

The comparison between the growth of eight populations from Psammosilene tunicoides at Yunnan Province was made by the tissue culture. The initial results showed out two populations from Yunshanping (Lijiang) and Xiaomoyu (Kunming) was dominant than orthers. It would be regard as one of fine germplasm resources for the culture of Psammosilence tunicoides.


Assuntos
Caryophyllaceae/crescimento & desenvolvimento , Plantas Medicinais/crescimento & desenvolvimento , Caryophyllaceae/anatomia & histologia , Caryophyllaceae/classificação , Meios de Cultura , Caules de Planta/crescimento & desenvolvimento , Técnicas de Cultura de Tecidos/métodos
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