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Although composite solid-state electrolytes (CSEs) are considered promising ionic conductors for high-energy lithium metal batteries, their unsatisfactory ionic conductivity, low mechanical strength, poor thermal stability, and narrow voltage window limit their practical applications. We have prepared a new lithium superionic conductor (Li-HA-F) with an ultralong nanofiber structure and ultrahigh room-temperature ionic conductivity (12.6 mS cm-1). When it is directly coupled with a typical poly(ethylene oxide)-based solid electrolyte, the Li-HA-F nanofibers endow the resulting CSE with high ionic conductivity (4.0 × 10-4 S cm-1 at 30 °C), large Li+ transference number (0.66), and wide voltage window (5.2 V). Detailed experiments and theoretical calculations reveal that Li-HA-F supplies continuous dual-conductive pathways and results in stable LiF-rich interfaces, leading to its excellent performance. Moreover, the Li-HA-F nanofiber-reinforced CSE exhibits good heat/flame resistance and flexibility, with a high breaking strength (9.66 MPa). As a result, the Li/Li half cells fabricated with the Li-HA-F CSE exhibit good stability over 2000 h with a high critical current density of 1.4 mA cm-2. Furthermore, the LiFePO4/Li-HA-F CSE/Li and LiNi0.8Co0.1Mn0.1O2/Li-HA-F CSE/Li solid-state batteries deliver high reversible capacities over a wide temperature range with a good cycling performance.
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To develop radiolabeled FGFR2-targeting probes for visualizing fibroblast growth factor receptor (FGFR) expression levels in the tumor microenvironment, four novel 99mTc-labeled FGFR2-targeting peptides ([99mTc]Tc-FGFR2-1, [99mTc]Tc-FGFR2-2, [99mTc]Tc-FGFR2-3, and [99mTc]Tc-FGFR2-4) with different amino acid linkers between the targeted peptide moiety and the 99mTc chelating group were designed and synthesized. The in vitro cellular inhibition, internalization, and efflux results demonstrated that the four 99mTc complexes exhibited FGFR2-specific binding and prolonged cellular retention in DU145 human prostate cancer cells, which indicated that modification from the glycine side (N-terminal) of CH02 was feasible. Among them, [99mTc]Tc-FGFR2-1 exhibited the highest in vitro cellular uptake and in vivo tumor uptake at 30 min postinjection, and tumor uptake could be significantly inhibited by the competitor CH02 (53% inhibited, p < 0.05), suggesting the tumor-specific targeting ability of [99mTc]Tc-FGFR2-1. The DU145-xenografted tumor lesions were clearly visualized by single photon emission computed tomography (SPECT)/CT at 30 min postinjection of [99mTc]Tc-FGFR2-1, highlighting its potential as a SPECT imaging probe for tumor FGFR2 detection.
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Melanoma , Peptídeos , Masculino , Humanos , Peptídeos/química , Tomografia Computadorizada de Emissão de Fóton Único/métodos , Melanoma/metabolismo , Quelantes , Ligação Proteica , Linhagem Celular Tumoral , Microambiente Tumoral , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/metabolismoRESUMO
Palmitoylation is a type of lipid modification that plays an important role in various aspects of neuronal function. Over the past few decades, several studies have shown that the palmitoylation of synaptic proteins is involved in neurotransmission and synaptic functions. Palmitoyl acyltransferases (PATs), which belong to the DHHC family, are major players in the regulation of palmitoylation. Dysregulated palmitoylation of synaptic proteins and mutated/dysregulated DHHC proteins are associated with several neurodegenerative diseases, such as Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD). In this review, we summarize the recent discoveries on the subcellular distribution of DHHC proteins and analyze their expression patterns in different brain cells. In particular, this review discusses how palmitoylation of synaptic proteins regulates synaptic vesicle exocytotic fusion and the localization, clustering, and transport of several postsynaptic receptors, as well as the role of palmitoylation of other proteins in regulating synaptic proteins. Additionally, some of the specific known associations of these factors with neurodegenerative disorders are explored, with a few suggestions for the development of therapeutic strategies. Finally, this review provides possible directions for future research to reveal detailed and specific mechanisms underlying the roles of synaptic protein palmitoylation.
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Lipoilação , Doenças Neurodegenerativas , Sinapses , Humanos , Doenças Neurodegenerativas/metabolismo , Animais , Sinapses/metabolismo , Aciltransferases/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Proteínas do Tecido Nervoso/genética , Transmissão SinápticaRESUMO
BACKGROUND: In previous systematic reviews, meta-analysis was lacking, resulting in the statistical difference between the data of different surgeries being impossible to judge. This meta-analysis aims to contrast the fertility results and cancer outcomes between open and minimally invasive surgery. METHOD: We systematically searched databases including PubMed, Embase, Cochrane, and Scopus to collect studies that included open and minimally invasive radical trachelectomy. A random-effect model calculated the weighted average difference of each primary outcome via Review Manager V.5.4. RESULT: Eight studies (1369 patients) were incorporated into our study. For fertility results, the Open group excels MIS group in pregnancies-Third trimester delivery [OR = 2.68; 95% CI (1.29, 5.59); P = 0.008]. Nevertheless, there is no statistical difference in clinical pregnancy, miscarriage, and second-trimester rate. Concerning cancer outcomes, no difference was detected in the overall survival [OR = 1.56; 95% CI (0.70, 3.45); P = 0.27] and recurrence [OR = 0.63; 95% CI (0.35, 1.12); P = 0.12]. Concerning surgery-related outcomes, the comprehensive effects revealed that the estimated blood loss of the Open group was higher than that of the MIS group[MD = 139.40; 95% CI (79.05, 199.75); P < 0.0001]. However, there was no difference between the postoperative complication rate in the two groups [OR = 1.52; 95% CI (0.89, 2.60); P = 0.12]. CONCLUSION: This meta-analysis suggested that the fertility result of the Open group may be better than the MIS group, while the MIS group has better surgery-related outcomes. Owing to the poor cases of our study, a more robust conclusion requires more relevant articles in the future. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022352999.
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Preservação da Fertilidade , Traquelectomia , Neoplasias do Colo do Útero , Feminino , Humanos , Gravidez , Fertilidade , Preservação da Fertilidade/métodos , Procedimentos Cirúrgicos Minimamente Invasivos/efeitos adversos , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Segundo Trimestre da Gravidez , Traquelectomia/efeitos adversos , Traquelectomia/métodos , Neoplasias do Colo do Útero/cirurgiaRESUMO
Although high ionic conductivities have been achieved in most solid-state electrolytes used in lithium metal batteries (LMBs), rapid and stable lithium-ion transport between solid-state electrolytes and lithium anodes remains a great challenge due to the high interfacial impedances and infinite volume changes of metallic lithium. In this work, a chemical vapor-phase fluorination approach is developed to establish a lithiophilic surface on rubber-derived electrolytes, which results in the formation of a resilient, ultrathin, and mechanically integral LiF-rich layer after electrochemical cycling. The resulting ultraconformal layer chemically connects the electrolyte and lithium anode and maintains dynamic contact during operation, thus facilitating rapid and stable lithium-ion transport across interfaces, as well as promoting uniform lithium deposition and inhibiting side reactions between electrolyte components and metallic lithium. LMBs containing the novel electrolyte have an ultralong cycling life of 2500â h and deliver a high critical current density of 1.1â mA cm-2 in lithium symmetric cells as well as showing good stability over 300â cycles in a full cell.
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Immune-mediated thrombotic thrombocytopenia purpura (iTTP) is a rare microvascular disease characterized by severe disseminated microvascular thrombose-bleeding syndrome. Caplacizumab has been approved for the treatment of iTTP in combination with Plasma Exchange (PE) and immunosuppressive therapy, but its role in iTTP therapy remains uncertain. Therefore, we conducted a meta-analysis to investigate the safety and efficacy of caplacizumab for the treatment of patients with iTTP. We searched electronic databases (PubMed, Embase, Cochrane Library, and Scopus) and reference lists of relevant articles to find articles published from 2015 to 2022. The time to normalization of the platelet count of the group caplacizumab is shorter than the group placebo (SMDâ=â-0.72; 95% CI -0.88 to -0.56; P â<â0.05). Caplacizumab reduced the incidence of mortality (ORâ=â0.41; 95% CI 0.18-0.92; P â<â0.05), exacerbations (ORâ=â0.10; 95% CI 0.05-0.18; P â<â0.05), and recurrence (ORâ=â0.17; 95% CI 0.06-0.50; P â<â0.05). However, the bleeding events in the caplacizumab group were higher than those in the placebo group, especially severe bleeding events. There was no difference in ADAMTS13 activity and thromboembolic events between the two groups. Our analysis indicated that caplacizumab is effective and well tolerated for the treatment of iTTP. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42022362370.
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Púrpura Trombocitopênica Trombótica , Anticorpos de Domínio Único , Humanos , Púrpura Trombocitopênica Trombótica/tratamento farmacológico , Púrpura Trombocitopênica Trombótica/terapia , Anticorpos de Domínio Único/uso terapêutico , Troca Plasmática/métodos , Resultado do TratamentoRESUMO
Amyloid-beta (Aß) is a key factor in the onset and progression of Alzheimer's disease (AD). Selenium (Se) compounds show promise in AD treatment. Here, we revealed that selenoprotein K (SELENOK), a selenoprotein involved in immune regulation and potentially related to AD pathology, plays a critical role in microglial immune response, migration, and phagocytosis. In vivo and in vitro studies corroborated that SELENOK deficiency inhibits microglial Aß phagocytosis, exacerbating cognitive deficits in 5xFAD mice, which are reversed by SELENOK overexpression. Mechanistically, SELENOK is involved in CD36 palmitoylation through DHHC6, regulating CD36 localization to microglial plasma membranes and thus impacting Aß phagocytosis. CD36 palmitoylation was reduced in the brains of patients and mice with AD. Se supplementation promoted SELENOK expression and CD36 palmitoylation, enhancing microglial Aß phagocytosis and mitigating AD progression. We have identified the regulatory mechanisms from Se-dependent selenoproteins to Aß pathology, providing novel insights into potential therapeutic strategies involving Se and selenoproteins.
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Doença de Alzheimer , Antígenos CD36 , Microglia , Selenoproteínas , Animais , Humanos , Camundongos , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Modelos Animais de Doenças , Lipoilação , Camundongos Transgênicos , Microglia/metabolismo , Fagocitose , Selenoproteínas/genética , Selenoproteínas/metabolismo , Antígenos CD36/metabolismoRESUMO
BACKGROUND: The use of adaptive designs in cancer trials has considerably increased worldwide in recent years, along with the release of various guidelines for their application. This systematic review aims to comprehensively summarize the key methodological and executive features of adaptive designs in cancer clinical trials. METHODS: A comprehensive search from PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials was conducted to screen eligible clinical trials that employed adaptive designs and were conducted in cancer patients. The methodological and executive characteristics of adaptive designs were the main measurements extracted. Descriptive analyses, primarily consisting of frequency and percentage, were employed to analyzed and reported the data. RESULTS: A total of 180 cancer clinical trials with adaptive designs were identified. The first three most common type of adaptive design was the group sequential design (n=114, 63.3â¯%), adaptive dose-finding design (n=22, 12.2â¯%), and adaptive platform design (n=16, 8.9â¯%). The results showed that 4.4â¯% (n=8) of trials conducted post hoc modifications, and around 29.4â¯% (n=53) did not provide the methods for controlling type I errors. Among phase II or above trials, 79.9â¯% (112/140) applied the surrogate endpoint as the primary outcome in these trials. Importantly, 27.2â¯% (49/180) of trials did not report clear information on the independent data monitoring committee (iDMC), and 13.3â¯% (n=24) without clear information on interim analyses. Interim analyses suggested 34.4â¯% (62/180) of trials being stopped for futility, 10.6â¯% (n=19) for efficacy, and 2.2â¯% (n=4) for safety concerns in the early stage. CONCLUSIONS: This study emphasizes adaptive designs in cancer trials face significant challenges in their design or strict implementation according to protocol, which might significantly compromise the validity and integrity of trials. It is thus important for researchers, sponsors, and policymakers to actively oversee and guide their application.
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Ensaios Clínicos como Assunto , Neoplasias , Projetos de Pesquisa , Humanos , Neoplasias/terapia , Neoplasias/tratamento farmacológicoRESUMO
INTRODUCTION: The increased prevalence of obesity worldwide and low incidence of postoperative complications make the laparoscopic sleeve gastrectomy (LSG) a clear public choice for obese-related individuals. Pre-existing studies reported contentious outcomes regarding the association with gastrointestinal symptoms after adding omentopexy (Ome) or gastropexy (Gas) to LSG. The present meta-analysis attempted to evaluate the pros and cons of operating Ome/Gas after LSG concerning gastrointestinal symptoms. METHODS: The data extraction and study quality assessment were independently performed by two individuals. The PubMed, EMBASE, Scopus, and Cochrane Library databases were systematically searched up to October 1, 2022, using the keywords LSG, omentopexy, and gastropexy to identify randomized controlled trial studies. RESULTS: Of the original 157 records, 13 studies with 3515 patients were included. LSG with Ome/Gas excels the LSG group in nausea (odds ratio [OR] = 0.57; 95% CI[0.46, 0.70]; P < .00001), reflux (OR = 0.57; 95% CI [0.46, 0.70]; P < .00001), vomiting (OR = 0.41; 95% CI [0.25, 0.67]; P = .0004) on gastrointestinal symptoms and bleeding (OR = 0.36; 95% CI [0.22, 0.59]; P < .0001), leakage (OR = 0.19; 95% CI [0.09, 0.43]; P < .0001), gastric torsion (OR = 0.23; 95% CI [0.07, 0.75]; P = .01) on post-LSG complications. Further, LSG with Ome/Gas was superior to LSG regarding the result of excess body mass index loss in 1 year after surgery (mean difference = 1.83; 95% CI [0.59, 3.07]; P = .004). However, no significant associations were shown between groups in wound infection and the resulting weight or body mass index 1 year after surgery. Of note, subgroup analysis indicated that gastroesophageal reflux disease can be alleviated by adding Ome/Gas post-LSG in those who used small bougies from 32 to 36 Fr (OR = 0.24; 95% CI [0.17, 0.34]; P < .00001) in contrast with large bougies over 36 Fr. CONCLUSION: Most results elucidated the impact of adding Ome/Gas after LSG in reducing the incidence of gastrointestinal symptoms. Additionally, more studies should be conducted to find the relations between other indicators in the present analysis due to the poor cases.
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Refluxo Gastroesofágico , Gastropexia , Laparoscopia , Obesidade Mórbida , Humanos , Obesidade Mórbida/cirurgia , Gastropexia/efeitos adversos , Laparoscopia/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto , Obesidade/cirurgia , Refluxo Gastroesofágico/cirurgia , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgia , Gastrectomia/efeitos adversos , Gastrectomia/métodos , Resultado do Tratamento , Estudos RetrospectivosRESUMO
Owing to the strong antioxidant capacity of selenium (Se) in vivo, a variety of Se compounds have been shown to have great potential for improving the main pathologies and cognitive impairment in Alzheimer's disease (AD) models. However, the differences in the anti-AD effects and mechanisms of different Se compounds are still unclear. Theoretically, the absorption and metabolism of different forms of Se in the body vary, which directly determines the diversification of downstream regulatory pathways. In this study, low doses of Se-methylselenocysteine (SMC), selenomethionine (SeM), or sodium selenate (SeNa) were administered to triple transgenic AD (3× Tg-AD) mice for short time periods. AD pathology, activities of selenoenzymes, and metabolic profiles in the brain were studied to explore the similarities and differences in the anti-AD effects and mechanisms of the three Se compounds. We found that all of these Se compounds significantly increased Se levels and antioxidant capacity, regulated amino acid metabolism, and ameliorated synaptic deficits, thus improving the cognitive capacity of AD mice. Importantly, SMC preferentially increased the expression and activity of thioredoxin reductase and reduced tau phosphorylation by inhibiting glycogen synthase kinase-3 beta (GSK-3ß) activity. Glutathione peroxidase 1 (GPx1), the selenoenzyme most affected by SeM, decreased amyloid beta production and improved mitochondrial function. SeNa improved methionine sulfoxide reductase B1 (MsrB1) expression, reflected in AD pathology as promoting the expression of synaptic proteins and restoring synaptic deficits. Herein, we reveal the differences and mechanisms by which different Se compounds improve multiple pathologies of AD and provide novel insights into the targeted administration of Se-containing drugs in the treatment of AD.
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Selenium, a trace element associated with memory impairment and glucose metabolism, mainly exerts its function through selenoproteins. SELENOM is a selenoprotein located in the endoplasmic reticulum (ER) lumen. Our study demonstrates for the first time that SELENOM knockout decreases synaptic plasticity and causes memory impairment in 10-month-old mice. In addition, SELENOM knockout causes hyperglycaemia and disturbs glucose metabolism, which is essential for synapse formation and transmission in the brain. Further research reveals that SELENOM knockout leads to inhibition of the brain insulin signaling pathway [phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR/p70 S6 kinase pathway], which may impair synaptic plasticity in mice. High-fat diet (HFD) feeding suppresses the brain insulin signaling pathway in SELENOM knockout mice and leads to earlier onset of cognitive impairment at 5 months of age. In general, our study demonstrates that SELENOM knockout induces synaptic deficits via the brain insulin signaling pathway, thus leading to cognitive dysfunction in mice. These data strongly suggest that SELENOM plays a vital role in brain glucose metabolism and contributes substantially to synaptic plasticity.
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Disfunção Cognitiva , Glucose , Animais , Camundongos , Encéfalo/metabolismo , Disfunção Cognitiva/genética , Disfunção Cognitiva/metabolismo , Dieta Hiperlipídica , Glucose/metabolismo , Insulina/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfatidilinositol 3-Quinases/metabolismo , Selenoproteínas/metabolismoRESUMO
OBJECTIVE: Exosomes in the central nervous system (CNS) have become an attractive area of research with great value. However, few bibliometric analysis has been conducted. The study aimed to visualize the scientific trends and research hotspots of exosomes in the CNS by bibliometric analysis. METHODS: All potential articles and reviews on exosomes in the CNS published in English from 2001 to 2021 were extracted from the Web of Science Core Collection. The visualization knowledge maps of critical indicators, including countries/regions, institutions, authors, journals, references, and keywords, were generated by CiteSpace and VOSviewer software. Besides, each domain's quantitative and qualitative analysis was also considered. RESULTS: A total of 2,629 papers were included. The number of exosomes-related publications and citations regarding CNS increased yearly. These publications came from 2,813 institutions in 77 countries/regions, led by the United States and China. Harvard University was the most influential institution, while the National Institutes of Health was the most critical funding source. We identified 14,468 authors, among which Kapogiannis D had the most significant number of articles and the highest H-index, while Théry C was the most frequently co-cited. The cluster analysis of keywords generated 13 clusters. In summary, the topic of biogenesis, biomarker, and drug delivery will serve as hotspots in future research. CONCLUSION: Exosomes-related CNS research has gained considerable attention in the past 20 years. The sources and biological functions of exosomes and their promising role in diagnosing and treating CNS diseases are considered hotspots in this field. The clinical translation of the results from exosomes-related CNS research will be of great importance in the future.
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Aberrant lipid metabolism is reported to be closely related to the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease (AD). Selenium (Se) and folate are two ideal and safe nutritional supplements, whose biological effects include regulating redox and homocysteine (Hcy) homeostasis in vivo. Here, to achieve effective multitarget therapy for AD, we combined Se and folic acid in a co-supplementation regimen (Se-FA) to study the therapeutic potential and exact mechanism in two transgenic mouse models of AD (APP/Tau/PSEN and APP/PS1). In addition to a reduction in Aß generation and tau hyperphosphorylation, a restoration of synaptic plasticity and cognitive ability was observed in AD mice upon Se-FA administration. Importantly, by using untargeted metabolomics, we found that these improvements were dependent on the modulation of brain lipid metabolism, which may be associated with an antioxidant effect and the promotion of Hcy metabolism. Thus, from mechanism to effects, this study systematically investigated Se-FA as an intervention for AD, providing important mechanistic insights to inform its potential use in clinical trials.
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INTRODUCTION: The increased economic and social burdens for NAFLD worldwide make treating such a disease a significant public health issue. Metformin, a kind of insulin sensitizer generally used to treat type 2 diabetes, has been recently found to have efficacy on children's NAFLD in various areas such as glucolipid metabolism, intestinal bacterial metabolism, oxidative stress, and anti-inflammatory response. This article aims to provide an overview of the possible mechanisms of NAFLD in children and the potential therapeutic application of metformin. AREAS COVERED: The Cochrane Library, PubMed, Scopus, and EMBASE database was systematically searched on 12 April 2022, using the keywords metformin; non-alcoholic fatty liver disease; and children to identify similar studies. An additional search for recently published research was performed in June 2020. EXPERT OPINION: Although metformin has been proved to have an excellent therapeutic effect on children's NAFLD; we can still explore its potential impacts and mechanisms from different angles, such as combined medication. At the same time, we should also pay attention to its side effects.
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Diabetes Mellitus Tipo 2 , Metformina , Hepatopatia Gordurosa não Alcoólica , Criança , Humanos , Metformina/efeitos adversos , Hepatopatia Gordurosa não Alcoólica/diagnóstico , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/metabolismo , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Insulina , Anti-Inflamatórios/uso terapêuticoRESUMO
Here, two kinds of polysaccharide-based biocomposites were investigated. The enzymatically synthesized levan from Erwinia amylovora was applied as the matrix, while montmorillonite clay and bovine serum albumin (BSA) were used as additive in the biocomposite. To examine the properties of levan/MMT biocomposite, we choose different ratios between levan and MMT to implement the surface morphology observation, thermal property analysis, and rheological behavior determination. As a result, the levan/MMT biocomposite in a 2:1 blending ratio showed a significant improvement both in the thermal and rheological properties. Meanwhile, the 0.1 % levan/BSA nanoparticle showed the highest encapsulation capacity and surface charge as 53.13⯱â¯2.64 % and +3.92⯱â¯0.43â¯mV. Last but not least, the levan/BSA nanoparticle exhibited a slower and controlled release of the BSA from the system. All of these results indicated a potential application of levan-based biocomposite and nanoparticle.
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Bentonita/química , Materiais Biocompatíveis/química , Frutanos/química , Nanopartículas/química , Soroalbumina Bovina/química , Animais , Materiais Biocompatíveis/síntese química , Bovinos , Erwinia amylovora/enzimologia , Frutanos/biossíntese , Hexosiltransferases/metabolismo , Tamanho da Partícula , Proteínas Recombinantes/metabolismo , Propriedades de SuperfícieRESUMO
Levansucrase (EC 2.1.4.10, LS) has been used in the production of levan and levan-type fructooligosaccharides from sucrose; however, development of further application is restricted due to its poor thermostability. The LS from Brenneria sp. EniD312 was engineered using a structure-guided approach. Residue Glu404 was located in the "-TEAP-" motif and varied among LSs with different thermostabilities. Site-directed mutagenesis was performed in Glu404 and thermostability was evaluated by measuring the half-life and structural melting temperature (Tm) of the wild-type LS and its Glu404-mutant variants. The optimal temperature for the Glu404 mutants was similar to that of the wild-type enzyme, however, the Tm of E404 L mutant was enhanced by 2.8 °C and the half-life was increased by 12.5- and 1.3- fold at 35 and 45 °C, respectively. The other mutants E404 W, E404 V, E404I, and E404 F also showed a pronounced increase in Tm and thermostability. Finally, the improvement of thermostability of LS through mutation in Glu404 belonging to the "-TEAP"- motif could be ascribed to the change of microenvironment in the LS structure. The change of the micro-environment mainly included the enhanced structural stability between two ß-hairpins and the elevated hydrophobic interactions in the overall protein structure. This work proposes new insights into the thermostabilization mechanism of other LSs.
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Gammaproteobacteria/enzimologia , Gammaproteobacteria/genética , Hexosiltransferases/genética , Mutagênese Sítio-Dirigida/métodos , Proteínas Recombinantes/genética , Estabilidade Enzimática/genética , Hexosiltransferases/química , Hexosiltransferases/metabolismo , Concentração de Íons de Hidrogênio , Modelos Moleculares , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , TemperaturaRESUMO
Less attention has been focused on the industrial applications of levan-type fructan than that of inulin. Levan-type fructan is a unique homopolysaccharide consisting of fructose residues with a ß-(2, 6) linkage that possesses unique physiochemical properties such as low intrinsic viscosity. In this study, the recombinant levansucrase from Erwinia amylovora was used to efficiently produce levan from sucrose, and under optimised conditions, 195â¯g/L levan was produced from 500â¯g/L sucrose, with the highest conversion rate of 59%. The physicochemical properties of E. amylovora levan, such as surface morphology, thermal behaviour, rheology behaviour and texture analysis, were evaluated and compared with those of commercial gels, including xanthan, guar, carrageenan and Arabic gums. The produced E. amylovora levan showed a series of acceptable physicochemical properties, indicating a potential application for levan as a novel water-soluble micro gel. The conclusions of this study support the exploration of the use of more hydrogels in the food, medicinal and cosmetic industries.
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Erwinia amylovora/química , Frutanos/química , Água/química , Erwinia amylovora/enzimologia , Erwinia amylovora/metabolismo , Indústria Alimentícia , Frutanos/biossíntese , Géis , Hexosiltransferases/metabolismo , Peso Molecular , Solubilidade , TemperaturaRESUMO
OBJECTIVE: To evaluate of the valgus stability of the elbow after excision of the radial head, release of the medial collateral ligament (MCL), radial head replacement, and medial collateral ligament reconstruction. METHODS: Twelve fresh human cadaveric elbows were dissected to establish 7 kinds of specimens with elbow joint and ligaments as follow: (1) intact (n=12); (2) release of the medial collateral ligament (n=6); (3) excision of the radial head (n=6); (4) excision of the radial head together with release of the medial collateral ligament (n=12); (5) radial head replacement (n=6); (6) medial collateral ligament reconstruction (n=6); (7) radial head replacement together with medial collateral ligament reconstruction (n=12). Under two-newton-meter valgus torque, and at 0, 30, 60, 90 and 120 degrees of flexion with the forearm in supination, the valgus elbow laxity was quantified: All analysis was performed with SPSS 10.0 software. RESULTS: The least valgus laxity was seen in the intact state and its stability was the best. The laxity increased after resection of the radial head. The laxity was more after release of the medial collateral ligament than after resection of the radial head (P<0.01). The greatest laxity was observed after release of the medial collateral ligament together with resection of the radial head, so its stability was the worst. The laxity of the following implant of the radial head decreased. The laxity of the medial collateral ligament reconstruction was as much as that of the intact ligament (P>0.05). The laxity of the radial head replacement together with medial collateral ligament reconstruction became less. CONCLUSION: The results of this study show that the medial collateral ligament is the primary valgus stabilizer of the elbow and the radial head was a secondary constraint to resist valgus laxity. Both the medial collateral ligament reconstruction and the radial head replacement can restore the stability of elbow. If the radial head replacement can not be carried out, the reconstruction of the medial collateral ligament is acceptable.