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1.
Plant Cell ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38723161

RESUMO

The conserved microRNA (miRNA) miR408 enhances photosynthesis and compromises stress tolerance in multiple plants, but the cellular mechanism underlying its function remains largely unclear. Here, we show that in Arabidopsis (Arabidopsis thaliana), the transcript encoding the blue copper protein PLANTACYANIN (PCY) is the primary target for miR408 in vegetative tissues. PCY is preferentially expressed in the guard cells, and PCY is associated with the endomembrane surrounding individual chloroplasts. We found that the MIR408 promoter is suppressed by multiple abscisic acid (ABA)-responsive transcription factors, thus allowing PCY to accumulate under stress conditions. Genetic analysis revealed that PCY elevates reactive oxygen species (ROS) levels in the guard cells, promotes stomatal closure, reduces photosynthetic gas exchange, and enhances drought resistance. Moreover, the miR408-PCY module is sufficient to rescue the growth and drought tolerance phenotypes caused by gain- and loss-of-function of MYB44, an established positive regulator of ABA responses, indicating that the miR408-PCY module relays ABA signaling for regulating ROS homeostasis and drought resistance. These results demonstrate that miR408 regulates stomatal movement to balance growth and drought resistance, providing a mechanistic understanding of why miR408 is selected during land plant evolution and insights into the long-pursued quest of breeding drought-tolerant and high-yielding crops.

2.
Proc Natl Acad Sci U S A ; 119(3)2022 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-35022242

RESUMO

Leaf senescence is a critical process in plants and has a direct impact on many important agronomic traits. Despite decades of research on senescence-altered mutants via forward genetics and functional assessment of senescence-associated genes (SAGs) via reverse genetics, the senescence signal and the molecular mechanism that perceives and transduces the signal remain elusive. Here, using dark-induced senescence (DIS) of Arabidopsis leaf as the experimental system, we show that exogenous copper induces the senescence syndrome and transcriptomic changes in light-grown plants parallel to those in DIS. By profiling the transcriptomes and tracking the subcellular copper distribution, we found that reciprocal regulation of plastocyanin, the thylakoid lumen mobile electron carrier in the Z scheme of photosynthetic electron transport, and SAG14 and plantacyanin (PCY), a pair of interacting small blue copper proteins located on the endomembrane, is a common thread in different leaf senescence scenarios, including DIS. Genetic and molecular experiments confirmed that the PCY-SAG14 module is necessary and sufficient for promoting DIS. We also found that the PCY-SAG14 module is repressed by a conserved microRNA, miR408, which in turn is repressed by phytochrome interacting factor 3/4/5 (PIF3/4/5), the key trio of transcription factors promoting DIS. Together, these findings indicate that intracellular copper redistribution mediated by PCY-SAG14 has a regulatory role in DIS. Further deciphering the copper homeostasis mechanism and its interaction with other senescence-regulating pathways should provide insights into our understanding of the fundamental question of how plants age.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , MicroRNAs/metabolismo , Folhas de Planta/metabolismo , Senescência Vegetal/fisiologia , Arabidopsis/genética , Cobre , Escuridão , Regulação da Expressão Gênica de Plantas , Luz , Fitocromo/metabolismo , Senescência Vegetal/genética , Plantas Geneticamente Modificadas , Fatores de Transcrição/metabolismo , Transcriptoma
3.
Proteins ; 92(8): 933-945, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38591850

RESUMO

Bacterial adhesins attach their hosts to surfaces that the bacteria will colonize. This surface adhesion occurs through specific ligand-binding domains located towards the distal end of the long adhesin molecules. However, recognizing which of the many adhesin domains are structural and which are ligand binding has been difficult up to now. Here we have used the protein structure modeling program AlphaFold2 to predict structures for these giant 0.2- to 1.5-megadalton proteins. Crystal structures previously solved for several adhesin regions are in good agreement with the models. Whereas most adhesin domains are linked in a linear fashion through their N- and C-terminal ends, ligand-binding domains can be recognized by budding out from a companion core domain so that their ligand-binding sites are projected away from the axis of the adhesin for maximal exposure to their targets. These companion domains are "split" in their continuity by projecting the ligand-binding domain outwards. The "split domains" are mostly ß-sandwich extender modules, but other domains like a ß-solenoid can serve the same function. Bioinformatic analyses of Gram-negative bacterial sequences revealed wide variety ligand-binding domains are used in their Repeats-in-Toxin adhesins. The ligands for many of these domains have yet to be identified but known ligands include various cell-surface glycans, proteins, and even ice. Recognizing the ligands to which the adhesins bind could lead to ways of blocking colonization by bacterial pathogens. Engineering different ligand-binding domains into an adhesin has the potential to change the surfaces to which bacteria bind.


Assuntos
Adesinas Bacterianas , Modelos Moleculares , Domínios Proteicos , Adesinas Bacterianas/química , Adesinas Bacterianas/metabolismo , Sítios de Ligação , Ligação Proteica , Aderência Bacteriana , Ligantes , Cristalografia por Raios X
4.
J Exp Bot ; 75(5): 1615-1632, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-37988280

RESUMO

Heterotrimeric G proteins play key roles in cellular processes. Although phenotypic analyses of Arabidopsis Gß (AGB1) mutants have implicated G proteins in abscisic acid (ABA) signaling, the AGB1-mediated modules involved in ABA responses remain unclear. We found that a partial AGB1 protein was localized to the nucleus where it interacted with ABA-activated VirE2-interacting protein 1 (VIP1) and mitogen-activated protein kinase 3 (MPK3). AGB1 acts as an upstream negative regulator of VIP1 activity by initiating responses to ABA and drought stress, and VIP1 regulates the ABA signaling pathway in an MPK3-dependent manner in Arabidopsis. AGB1 outcompeted VIP1 for interaction with the C-terminus of MPK3, and prevented phosphorylation of VIP1 by MPK3. Importantly, ABA treatment reduced AGB1 expression in the wild type, but increased in vip1 and mpk3 mutants. VIP1 associates with ABA response elements present in the AGB1 promoter, forming a negative feedback regulatory loop. Thus, our study defines a new mechanism for fine-tuning ABA signaling through the interplay between AGB1 and MPK3-VIP1. Furthermore, it suggests a common G protein mechanism to receive and transduce signals from the external environment.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Subunidades beta da Proteína de Ligação ao GTP , Ácido Abscísico/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Subunidades beta da Proteína de Ligação ao GTP/genética , Subunidades beta da Proteína de Ligação ao GTP/metabolismo , Fosforilação
5.
Plant Cell ; 33(5): 1506-1529, 2021 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-33616669

RESUMO

Light-dependent seed germination is a vital process for many seed plants. A decisive event in light-induced germination is degradation of the central repressor PHYTOCHROME INTERACTING FACTOR 1 (PIF1). The balance between gibberellic acid (GA) and abscisic acid (ABA) helps to control germination. However, the cellular mechanisms linking PIF1 turnover to hormonal balancing remain elusive. Here, employing far-red light-induced Arabidopsis thaliana seed germination as the experimental system, we identified PLANTACYANIN (PCY) as an inhibitor of germination. It is a blue copper protein associated with the vacuole that is both highly expressed in mature seeds and rapidly silenced during germination. Molecular analyses showed that PIF1 binds to the miR408 promoter and represses miR408 accumulation. This in turn posttranscriptionally modulates PCY abundance, forming the PIF1-miR408-PCY repression cascade for translating PIF1 turnover to PCY turnover during early germination. Genetic analysis, RNA-sequencing, and hormone quantification revealed that PCY is necessary and sufficient to maintain the PIF1-mediated seed transcriptome and the low-GA-high-ABA state. Furthermore, we found that PCY domain organization and regulation by miR408 are conserved features in seed plants. These results revealed a cellular mechanism whereby PIF1-relayed external light signals are converted through PCY turnover to internal hormonal profiles for controlling seed germination.


Assuntos
Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Germinação , Luz , Metaloproteínas/metabolismo , MicroRNAs/metabolismo , Sementes/crescimento & desenvolvimento , Transdução de Sinais , Ácido Abscísico/metabolismo , Proteínas de Arabidopsis/genética , Sequência de Bases , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Sequência Conservada , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Inativação Gênica , Genes de Plantas , Germinação/genética , Giberelinas/metabolismo , MicroRNAs/genética , Modelos Biológicos , Filogenia , Regiões Promotoras Genéticas/genética , Ligação Proteica/genética , Ligação Proteica/efeitos da radiação , Plântula/efeitos da radiação , Sementes/genética , Transdução de Sinais/efeitos da radiação , Vacúolos/metabolismo , Vacúolos/efeitos da radiação
6.
New Phytol ; 239(1): 102-115, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-36994607

RESUMO

Sporopollenin is one of the most structurally sophisticated and chemically recalcitrant biopolymers. In higher plants, sporopollenin is the dominant component of exine, the outer wall of pollen grains, and contains covalently linked phenolics that protect the male gametes from harsh environments. Although much has been learned about the biosynthesis of sporopollenin precursors in the tapetum, the nutritive cell layer surrounding developing microspores, little is known about how the biopolymer is assembled on the microspore surface. We identified SCULP1 (SKS clade universal in pollen) as a seed plant conserved clade of the multicopper oxidase family. We showed that SCULP1 in common wheat (Triticum aestivum) is specifically expressed in the microspore when sporopollenin assembly takes place, localized to the developing exine, and binds p-coumaric acid in vitro. Through genetic, biochemical, and 3D reconstruction analyses, we demonstrated that SCULP1 is required for p-coumaroylation of sporopollenin, exine integrity, and pollen viability. Moreover, we found that SCULP1 accumulation is compromised in thermosensitive genic male sterile wheat lines and its expression partially restored exine integrity and male fertility. These findings identified a key microspore protein in autonomous sporopollenin polymer assembly, thereby laying the foundation for elucidating and engineering sporopollenin biosynthesis.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Triticum/genética , Triticum/metabolismo , Biopolímeros/metabolismo , Pólen/metabolismo , Regulação da Expressão Gênica de Plantas
7.
BMC Geriatr ; 23(1): 698, 2023 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-37891456

RESUMO

BACKGROUND: This study aimed to construct a risk prediction model to estimate the odds of osteoporosis (OP) in elderly patients with type 2 diabetes mellitus (T2DM) and evaluate its prediction efficiency. METHODS: This study included 21,070 elderly patients with T2DM who were hospitalized at six tertiary hospitals in Southwest China between 2012 and 2022. Univariate logistic regression analysis was used to screen for potential influencing factors of OP and least absolute shrinkage. Further, selection operator regression (LASSO) and multivariate logistic regression analyses were performed to select variables for developing a novel predictive model. The area under the receiver operating characteristic curve (AUROC), calibration curve, decision curve analysis (DCA), and clinical impact curve (CIC) were used to evaluate the performance and clinical utility of the model. RESULTS: The incidence of OP in elderly patients with T2DM was 7.01% (1,476/21,070). Age, sex, hypertension, coronary heart disease, cerebral infarction, hyperlipidemia, and surgical history were the influencing factors. The seven-variable model displayed an AUROC of 0.713 (95% confidence interval [CI]:0.697-0.730) in the training set, 0.716 (95% CI: 0.691-0.740) in the internal validation set, and 0.694 (95% CI: 0.653-0.735) in the external validation set. The optimal decision probability cut-off value was 0.075. The calibration curve (bootstrap = 1,000) showed good calibration. In addition, the DCA and CIC demonstrated good clinical practicality. An operating interface on a webpage ( https://juntaotan.shinyapps.io/osteoporosis/ ) was developed to provide convenient access for users. CONCLUSIONS: This study constructed a highly accurate model to predict OP in elderly patients with T2DM. This model incorporates demographic characteristics and clinical risk factors and may be easily used to facilitate individualized prediction.


Assuntos
Diabetes Mellitus Tipo 2 , Osteoporose , Idoso , Humanos , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/epidemiologia , Estudos Retrospectivos , Osteoporose/diagnóstico , Osteoporose/epidemiologia , Fatores de Risco , Infarto Cerebral
8.
New Phytol ; 236(3): 878-892, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35832006

RESUMO

In Arabidopsis, copper (Cu) transport to the ethylene receptor ETR1 mediated using RAN1, a Cu transporter located at the endoplasmic reticulum (ER), and Cu homeostasis mediated using SPL7, the key Cu-responsive transcription factor, are two deeply conserved vital processes. However, whether and how the two processes interact to regulate plant development remain elusive. We found that its C-terminal transmembrane domain (TMD) anchors SPL7 to the ER, resulting in dual compartmentalisation of the transcription factor. Immunoprecipitation coupled mass spectrometry, yeast-two-hybrid assay, luciferase complementation imaging and subcellular co-localisation analyses indicate that SPL7 interacts with RAN1 at the ER via the TMD. Genetic analysis revealed that the ethylene-induced triple response was significantly compromised in the spl7 mutant, a phenotype rescuable by RAN1 overexpression but not by SPL7 without the TMD. The genetic interaction was corroborated by molecular analysis showing that SPL7 modulates RAN1 abundance in a TMD-dependent manner. Moreover, SPL7 is feedback regulated by ethylene signalling via EIN3, which binds the SPL7 promoter and represses its transcription. These results demonstrate that ER-anchored SPL7 constitutes a cellular mechanism to regulate RAN1 in ethylene signalling and lay the foundation for investigating how Cu homeostasis conditions ethylene sensitivity in the developmental context.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Cobre/metabolismo , Proteínas de Ligação a DNA/metabolismo , Retículo Endoplasmático/metabolismo , Etilenos/metabolismo , Regulação da Expressão Gênica de Plantas , Fatores de Transcrição/metabolismo
9.
J Neurooncol ; 145(1): 23-34, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31482267

RESUMO

BACKGROUND AND PURPOSE: microRNAs are small noncoding RNAs that play important roles in cancer regulation. In this study, we investigated the expression, functional effects and mechanisms of action of microRNA-29a (miR-29a) in glioblastoma (GBM). METHODS: miR-29a expression levels in GBM cells, stem cells (GSCs) and human tumors as well as normal astrocytes and normal brain were measured by quantitative PCR. miR-29a targets were uncovered by target prediction algorithms, and verified by immunoblotting and 3' UTR reporter assays. The effects of miR-29a on cell proliferation, death, migration and invasion were assessed with cell counting, Annexin V-PE/7AAD flow cytometry, scratch assay and transwell assay, respectively. Orthotopic xenografts were used to determine the effects of miR-29a on tumor growth. RESULTS: Mir-29a was downregulated in human GBM specimens, GSCs and GBM cell lines. Exogenous expression of miR-29a inhibited GSC and GBM cell growth and induced apoptosis. miR-29a also inhibited GBM cell migration and invasion. PDGFC and PDGFA were uncovered and validated as direct targets of miR-29a in GBM. miR-29a downregulated PDGFC and PDGFA expressions at the transcriptional and translational levels. PDGFC and PDGFA expressions in GBM tumors, GSCs, and GBM established cell lines were higher than in normal brain and human astrocytes. Mir-29a expression inhibited orthotopic GBM xenograft growth. CONCLUSIONS: miR-29a is a tumor suppressor miRNA in GBM, where it inhibits cancer stem cells and tumor growth by regulating the PDGF pathway.


Assuntos
Neoplasias Encefálicas/patologia , Regulação Neoplásica da Expressão Gênica , Glioblastoma/patologia , Linfocinas/metabolismo , MicroRNAs/genética , Células-Tronco Neoplásicas/patologia , Fator de Crescimento Derivado de Plaquetas/metabolismo , Animais , Apoptose , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Movimento Celular , Proliferação de Células , Glioblastoma/genética , Glioblastoma/metabolismo , Humanos , Linfocinas/genética , Camundongos , Camundongos SCID , Células-Tronco Neoplásicas/metabolismo , Fator de Crescimento Derivado de Plaquetas/genética , Transdução de Sinais , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Wound Repair Regen ; 23(4): 495-505, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25847503

RESUMO

The purpose of the study is to examine the safety and effectiveness of topical autologous platelet-rich gel (APG) application on facilitating the healing of diabetic chronic refractory cutaneous ulcers. The study was designed as a prospective, randomized controlled trial between January 1, 2007 and December 31, 2011. Eligible inpatients at the Diabetic Foot Care Center of West China Hospital, Sichuan University (China) were randomly prescribed with a 12-week standard treatment of ulcers (the control group) or standard treatment plus topical application APG (the APG group). The wound healing grades (primary endpoint), time to complete healing, and healing velocity within 12 weeks were monitored as short-term effectiveness measurements, while side effects were documented safety endpoints. The rates of survival and recurrence within the follow up were recorded as long-term effectiveness endpoints. Analysis on total diabetic ulcers (DUs) (n = 117) and subgroup analysis on diabetic foot ulcers (DFUs) (n = 103) were both conducted. Standard treatment plus APG treatment was statistically more effective than standard treatment (p < 0.05 in both total DUs and subgroup of DFUs). The subjects defined as healing grade 1 were 50/59 (84.8%) in total DUs and 41/48 (85.4%) in DFUs in the APG group compared with 40/58 (69.0%) and 37/55 (67.3%) in the control group from intent to treat population. The Kaplan-Meier time-to-healing were significantly different between the two groups (p < 0.05 in both total DUs and subgroup of DFUs). No side effects were identified after topical APG application. The long-term survival and recurrence rates were comparative between groups (p > 0.05). This study shows that topical APG application plus standard treatment is safe and quite effective on diabetic chronic refractory cutaneous ulcers, compared with standard treatment.


Assuntos
Pé Diabético/terapia , Géis/administração & dosagem , Plasma Rico em Plaquetas , Úlcera Cutânea/terapia , Administração Tópica , China/epidemiologia , Pé Diabético/epidemiologia , Feminino , Seguimentos , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Úlcera Cutânea/epidemiologia , Resultado do Tratamento , Cicatrização
11.
Artigo em Inglês | MEDLINE | ID: mdl-38904876

RESUMO

In this paper, Bayer red mud (RM) and lotus leaf powder (LL) were used as the main materials, and KH2PO4 was added to modify the material. Under the condition of high-temperature carbonization, RMLL was prepared and phosphate modified red mud matrix composite (PRMLL) was prepared based on KH2PO4 modification, which can effectively remove Pb2+ from water. The optimum preparation and application conditions were determined through orthogonal experiment: dosage 0.1g, ratio 1:1, and temperature 600 °C. The effects of pH, dosage, and initial concentration on the adsorption of Pb2+ were studied. The pseudo-first-order, pseudo-second-order, and Elovich kinetic models were fitted to the experimental data. It was found that RMLL and PRMLL were more consistent with the pseudo-second-order kinetic model and chemisorption. Langmuir, Freundlich, Timkin, and Dubinin-Radushkevich isothermal adsorption models were used to fit the experimental data. It was found that RMLL and PRMLL were more consistent with Langmuir model. In addition, the maximum adsorption capacity of RMLL and PRMLL was 188.1 mg/g and 213.4 mg/g, respectively. It is larger than the adsorption capacity of their monomers. Therefore, the use of RMLL and PRMLL as the removal of Pb2+ from water is a potential application material.

12.
J Agric Food Chem ; 72(14): 8018-8026, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38557039

RESUMO

Phloretin is widely found in fruit and shows various biological activities. Here, we demonstrate the dimethylallylation, geranylation, and farnesylation, particularly the first dimethylallylation at the nonaromatic carbon of phloretin (1) by the fungal prenyltransferase AnaPT and its mutants. F265 was identified as a key amino acid residue related to dimethylallylation at the nonaromatic carbon of phloretin. Mutants AnaPT_F265D, AnaPT_F265G, AnaPT_F265P, AnaPT_F265C, and AnaPT_F265Y were discovered to generally increase prenylation activity toward 1. AnaPT_F265G catalyzes the O-geranylation selectively at the C-2' hydroxyl group, which involves an intramolecular hydrogen bond with the carbonyl group of 1. Seven products, 1D5, 1D7-1D9, 1G2, 1G4, and 1F2, have not been reported prior to this study. Twelve compounds, 1D3-1D9, 1G1-1G3, and 1F1-1F2, exhibited potential inhibitory effects on α-glucosidase with IC50 values ranging from 11.45 ± 0.87 to 193.80 ± 6.52 µg/mL. Among them, 1G1 with an IC50 value of 11.45 ± 0.87 µg/mL was the most potential α-glucosidase inhibitor, which is about 30 times stronger than the positive control acarbose with an IC50 value of 346.63 ± 15.65 µg/mL.


Assuntos
Dimetilaliltranstransferase , Floretina , Floretina/farmacologia , Indóis/química , Carbono , Catálise , Prenilação
13.
Dev Cell ; 59(5): 645-660.e8, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38325371

RESUMO

Macropinocytosis, an evolutionarily conserved endocytic pathway, mediates nonselective bulk uptake of extracellular fluid. It is the primary route for axenic Dictyostelium cells to obtain nutrients and has also emerged as a nutrient-scavenging pathway for mammalian cells. How cells adjust macropinocytic activity in various physiological or developmental contexts remains to be elucidated. We discovered that, in Dictyostelium cells, the transcription factors Hbx5 and MybG form a functional complex in the nucleus to maintain macropinocytic activity during the growth stage. In contrast, during starvation-induced multicellular development, the transcription factor complex undergoes nucleocytoplasmic shuttling in response to oscillatory cyclic adenosine 3',5'-monophosphate (cAMP) signals, which leads to increased cytoplasmic retention of the complex and progressive downregulation of macropinocytosis. Therefore, by coupling macropinocytosis-related gene expression to the cAMP oscillation system, which facilitates long-range cell-cell communication, the dynamic translocation of the Hbx5-MybG complex orchestrates a population-level adjustment of macropinocytic activity to adapt to changing environmental conditions.


Assuntos
Dictyostelium , Animais , Dictyostelium/metabolismo , Pinocitose/fisiologia , Citoplasma , Núcleo Celular , Fatores de Transcrição/metabolismo , Mamíferos
14.
J Comput Aided Mol Des ; 27(12): 989-1007, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24297454

RESUMO

We present a method to identify small molecule ligand binding sites and poses within a given protein crystal structure using GPU-accelerated Hamiltonian replica exchange molecular dynamics simulations. The Hamiltonians used vary from the physical end state of protein interacting with the ligand to an unphysical end state where the ligand does not interact with the protein. As replicas explore the space of Hamiltonians interpolating between these states, the ligand can rapidly escape local minima and explore potential binding sites. Geometric restraints keep the ligands from leaving the vicinity of the protein and an alchemical pathway designed to increase phase space overlap between intermediates ensures good mixing. Because of the rigorous statistical mechanical nature of the Hamiltonian exchange framework, we can also extract binding free energy estimates for all putative binding sites. We present results of this methodology applied to the T4 lysozyme L99A model system for three known ligands and one non-binder as a control, using an implicit solvent. We find that our methodology identifies known crystallographic binding sites consistently and accurately for the small number of ligands considered here and gives free energies consistent with experiment. We are also able to analyze the contribution of individual binding sites to the overall binding affinity. Our methodology points to near term potential applications in early-stage structure-guided drug discovery.


Assuntos
Bacteriófago T4/enzimologia , Simulação de Dinâmica Molecular , Muramidase/química , Muramidase/metabolismo , Solventes/química , Solventes/metabolismo , Sítios de Ligação , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Termodinâmica
15.
Environ Sci Pollut Res Int ; 30(58): 121684-121701, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37953422

RESUMO

In this study, a polyaniline/mesoporous silica (PANI/MCM-41) composite material that can be used as a filler for permeable reactive barrier (PRB) was prepared by in situ polymerization. Firstly, the adsorption capacity of PANI/MCM-41 on Cr (VI) in solution was investigated. The results show that the prepared PANI/MCM-41 exhibits a significant Cr (VI) adsorption capacity (~ 340 mg/g), and the adsorption process is more accurately described by the Langmuir isotherm and pseudo-second-order kinetic model. The thermodynamic functions evidenced that the Cr(VI) adsorption was an endothermic spontaneous process. In addition, adsorption-desorption cycle experiments proved the excellent reusability of the material. Subsequently, the material was utilized as a filler in the PRB for the remediation of Cr(VI)-contaminated soil using electrokinetic-permeable reactive barrier (EK-PRB) technology. The results show that compared with traditional electrokinetic remediation, the use of PANI/MCM-41 as an active filler can enlarge the current during remediation and enhance the conductivity of soil, which increases the removal rates of total Cr and Cr(VI) in soil (17.4% and 10.2%).


Assuntos
Cromo , Poluentes Químicos da Água , Adsorção , Cromo/análise , Dióxido de Silício , Solo , Íons , Cinética
16.
Clin Endocrinol (Oxf) ; 76(6): 810-5, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21854404

RESUMO

OBJECTIVE: Glycemic variability is poorly studied in the nondiabetic individuals and newly diagnosed patients with type 2 diabetes. The aim of the study is to investigate the characteristics of glucose fluctuations in subjects with normal glucose tolerance (NGT), impaired glucose regulation (IGR) and newly diagnosed, drug-naïve type 2 diabetes mellitus (DM-2). DESIGN AND PATIENTS: This is a cross-sectional study of three groups including 53 subjects with IGR, 56 DM-2 patients and 53 NGT individuals. Monitoring by a continuous glucose monitoring system (CGMS(®) System Gold(™)) was performed for three consecutive days. MEASUREMENTS: Mean blood glucose (MBG), standard deviation of MBG (SDBG), largest amplitude of glycemic excursions (LAGE) and mean amplitude of glycemic excursions (MAGE) were calculated to estimate intraday blood glucose variability. Interday variability of glucose was evaluated by absolute means of daily differences (MODD). Postprandial glucose excursion (PPGE) was calculated to assess the influence of meals on glucose fluctuation. RESULTS: Twenty-two percentage of NGT and 33.9% of IGR individuals experienced blood glucose ≥ 11.1 mmol/l; 49.1% of NGT, 50.9% of IGR and 30.8% of DM-2 participants had hypoglycemic episodes (CGM values <3.9 mmol/l). The IGR and DM-2 groups had greater SDBG (P = 0.010 and P < 0.001), LAGE (P = 0.014 and P < 0.001) and MAGE (P = 0.044 and P < 0.001) compared with the NGT group. Significantly greater MODD and PPGEs were found in the DM-2 groups than in the IGR and NGT groups (P < 0.001). The DM-2 patients had higher 72-MBG and glucose levels overnight than the NGT and IGR subjects (P < 0.001). In the patients with diabetes, MAGE was positively associated with MODD (r = 0.558, P < 0.001) and PPGEs (r = 0.738-0.843, P < 0.001). CONCLUSIONS: Glucose variability is present to an increasing degree from NGT to IGR and IGR to DM-2. Compared with the NGT individuals, the IGR and DM-2 subjects show more predominant intraday glucose fluctuations. The DM-2 patients demonstrate increased PPGEs, higher glucose levels overnight and greater interday fluctuations.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Intolerância à Glucose/sangue , Adulto , Glicemia/análise , Estudos Transversais , Feminino , Teste de Tolerância a Glucose , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Prandial/fisiologia
17.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 43(5): 762-5, 2012 Sep.
Artigo em Zh | MEDLINE | ID: mdl-23230756

RESUMO

OBJECTIVE: To evaluate the potential financial benefit of topical application of autologous platelet-rich gel (APG) in treating diabetic refractory cutaneous ulcers. METHODS: A single-center prospective randomized controlled trial was undertaken, with 117 patients with proven diabetic refractory cutaneous ulcers participating in the study. The patients who gave informed consents were randomly assigned into standard care group (n = 58) or standard care plus topical application of APG treatment group (n = 59). The outcome of healing and the medical expenditur and length of stay in the patients were compared between the two groups. RESULTS: The APG-treated group had better healing outcomes than the standard-treated group. The APG-treated group had 84.750 (50/59) complete healing and 98.31% improvement, higher than the 68.97% (40/58) and 75.86%, respectively, in the standard-treated group (P = 0.026). The median length for healing in the APG-treated patients was 36 days, shorter than the 45 days in the standard-treated patients (P = 0.012). The total medical expenditure and length of stay in hospitals were not significantly different between APG-treated patients [yen 38223 (23070-57398); 57 (41-94) days] and standard-treated patients [yen 35070 (24436-53649); 58 (31.75-58.50) days) (P = 0.455 and 0.301 respectively). Spendings on items such as medicine, artificial treatment, materials, interventional operation, surgical procedures, laboratory tests and other auxiliary examination, accommodations, meals, nursing care and debridement and dressing change were similar between the two groups (P > 0.05). CONCLUSION: There is an advantage for the topical application of APG on diabetic refractory cutaneous ulcers in terms of the healing outcomes. APG is a cost-effective choice for patients with diabetic refractory cutaneous ulcers.


Assuntos
Complicações do Diabetes/terapia , Pé Diabético/economia , Hospitalização/estatística & dados numéricos , Plasma Rico em Plaquetas , Úlcera Cutânea/economia , Administração Cutânea , Adulto , Idoso , Complicações do Diabetes/metabolismo , Pé Diabético/metabolismo , Pé Diabético/terapia , Feminino , Géis/economia , Custos Hospitalares , Hospitalização/economia , Humanos , Masculino , Pessoa de Meia-Idade , Transfusão de Plaquetas/métodos , Plasma Rico em Plaquetas/fisiologia , Estudos Prospectivos , Úlcera Cutânea/etiologia , Úlcera Cutânea/terapia , Cicatrização
18.
Front Public Health ; 10: 919549, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35836981

RESUMO

Background: The International Normalized Ratio (INR) is significantly associated with Hepatic Encephalopathy (HE) in patients with liver cirrhosis. However, the dose-response relationship between continuous INR changes and HE risk has not been clearly defined. Thus, our goal was to explore the continuous relationship between HE and INR among patients hospitalized with liver cirrhosis and to evaluate the role of the INR as a risk factor for HE in these patients. Methods: A total of 6,266 people were extracted from the Big Data Platform of the Medical Data Research Institute of Chongqing Medical University. In this study, unconditional logistic regression and restricted cubic spline (RCS) model were used to analyze the dose-response association of INR with HE. Alcoholic liver disease, smoking status, and drinking status were classified for subgroup analysis. Results: The prevalence of HE in the study population was 8.36%. The median INR was 1.4. After adjusting for alcoholic liver disease, age, smoking status, drinking status, total bilirubin, neutrophil percentage, total hemoglobin, aspartate aminotransferase, serum sodium, albumin, lymphocyte percentage, serum creatinine, red blood cell, and white blood cell, multivariate logistic regression analysis revealed that INR ≥ 1.5 (OR = 2.606, 95% CI: 2.072-3.278) was significantly related to HE risk. The RCS model showed a non-linear relationship between the INR and HE (non-linear test, χ2 = 30.940, P < 0.001), and an increased INR was an independent and adjusted dose-dependent risk factor for HE among patients with liver cirrhosis. Conclusion: This finding could guide clinicians to develop individualized counseling programs and treatments for patients with HE based on the INR risk stratification.


Assuntos
Encefalopatia Hepática , Hepatopatias Alcoólicas , Encefalopatia Hepática/complicações , Encefalopatia Hepática/etiologia , Humanos , Coeficiente Internacional Normatizado/efeitos adversos , Cirrose Hepática/complicações , Hepatopatias Alcoólicas/complicações , Fatores de Risco
19.
Genomics Proteomics Bioinformatics ; 20(4): 747-764, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33662619

RESUMO

MicroRNAs (miRNAs) are trans-acting small regulatory RNAs that work coordinately with transcription factors (TFs) to shape the repertoire of cellular mRNAs available for translation. Despite our growing knowledge of individual plant miRNAs, their global roles in gene regulatory networks remain mostly unassessed. Based on interactions obtained from public databases and curated from the literature, we reconstructed an integrated miRNA network in Arabidopsis that includes 66 core TFs, 318 miRNAs, and 1712 downstream genes. We found that miRNAs occupy distinct niches and enrich miRNA-containing feed-forward loops (FFLs), particularly those with miRNAs as intermediate nodes. Further analyses revealed that miRNA-containing FFLs coordinate TFs located in different hierarchical layers and that intertwined miRNA-containing FFLs are associated with party and date miRNA hubs. Using the date hub MIR858A as an example, we performed detailed molecular and genetic analyses of three interconnected miRNA-containing FFLs. These analyses revealed individual functions of the selected miRNA-containing FFLs and elucidated how the date hub miRNA fulfills multiple regulatory roles. Collectively, our findings highlight the prevalence and importance of miRNA-containing FFLs, and provide new insights into the design principles and control logics of miRNA regulatory networks governing gene expression programs in plants.


Assuntos
Arabidopsis , MicroRNAs , MicroRNAs/genética , MicroRNAs/metabolismo , Redes Reguladoras de Genes , Arabidopsis/genética , Arabidopsis/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Bases de Dados Factuais
20.
J Thorac Cardiovasc Surg ; 164(5): 1444-1455.e4, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-33892946

RESUMO

OBJECTIVES: Improved durability and preference to avoid anticoagulation have led to increasing use of bioprostheses in younger patients despite the need for eventual reoperation. Therefore, we compared in-hospital complications, reoperation, and survival after bioprosthetic and mechanical aortic valve replacement. METHODS: From January 1990 to January 2020, 6143 patients underwent isolated aortic valve replacement at Cleveland Clinic; 637 patients received a mechanical prosthesis and 5506 a bioprosthesis. Propensity matching identified 527 well-matched pairs (83% of possible matches) for comparison of perioperative outcomes. The average age of patients was 54 years in the bioprosthesis group and 55 years in the mechanical prosthesis group. Random Forest machine-learning analysis was performed to compare survival using the entire cohort of 6143 patients. RESULTS: Among matched patients, major in-hospital complications, including stroke, deep sternal wound infection, and reoperation for bleeding, were similar, as was in-hospital mortality (2 in the bioprosthesis group [0.38%] vs 3 in the mechanical prosthesis group [0.57%]; P > .9). Patients receiving a bioprosthesis had shorter hospital stays (median 6 vs 7 days, P < .0001). Fifty-one patients (32% at 14 years) in the bioprosthesis group and 17 patients in the mechanical prosthesis group (8% at 14 years) underwent reoperation (P [log-rank] < .0001); 5-year survival after reoperation was 85% versus 82% (P = .6). Risk-adjusted Random Forest prediction of 18-year survival was 60% in the bioprosthetic group and 58% in the mechanical prosthesis group. CONCLUSIONS: Aortic valve bioprostheses are associated with excellent short-term outcomes and 18-year survival similar to that of patients receiving mechanical valves. Reoperation does not adversely affect survival. These results suggest that risk for reoperation alone should not deter the use of bioprostheses in younger patients.


Assuntos
Bioprótese , Implante de Prótese de Valva Cardíaca , Próteses Valvulares Cardíacas , Anticoagulantes/efeitos adversos , Valva Aórtica/diagnóstico por imagem , Valva Aórtica/cirurgia , Bioprótese/efeitos adversos , Próteses Valvulares Cardíacas/efeitos adversos , Implante de Prótese de Valva Cardíaca/efeitos adversos , Humanos , Pessoa de Meia-Idade , Desenho de Prótese , Reoperação , Estudos Retrospectivos , Análise de Sobrevida , Resultado do Tratamento
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