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1.
Mol Cell Biochem ; 2024 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-38587786

RESUMEN

Non-SMC (Structural Maintenance of Chromosomes) condensin I complex subunit H (NCAPH) has been shown to facilitate progression and predict adverse prognostic outcome in many cancer types. However, the function of NCAPH in gliomas is still unclear. Series of experiments were taken to uncover the function of NCAPH in glioma. The expression of NCAPH and potential mechanism regulating progression of glioma was verified by bioinformatics analysis. Lentiviral transfection was used for establishment of loss-of-function and gain-of-function cell lines. CCK-8 assay and Colony-formation assay were used to evaluate proliferation. Transwell assay and Cell wound healing assay were used to assess migration and invasion. Cell cycle and apoptosis were measured by flow cytometry. Protein and RNA were quantified by WB and RT-PCR, respectively. The nude mice model of glioma was used to evaluate the effect of NCAPH in vivo. The expression of NCAPH increased significantly in glioma tissues and correlated with WHO grade, IDH wild-type and non-1p/19q codeletion. Glioma patients with high expression of NCAPH had an undesirable prognosis. Functionally, upregulated NCAPH promotes the malignant hallmarks of glioma cells in vivo and in vitro. NCAPH correlated with DNA damage repair ability of glioma cells and facilitated the proliferation, invasion, and migration of glioma cells by promoting the PI3K/AKT signaling pathway. This study identifies the important pro-tumor role of NCAPH in glioma and suggests that NCAPH is a potential therapeutic target.

2.
Neurosurg Rev ; 47(1): 417, 2024 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-39123083

RESUMEN

Glioma, especially glioblastoma patients, present highly heterogeneous and immunosuppressive microenvironment, leading to their poor response to treatment and survival. Targeting the tumor microenvironment is considered a promising therapeutic strategy. M2 macrophages are highly infiltrated in glioma tissue, even up to 50% of the total number of bulk tissue cells. Here, we identified GPR65 as the hub gene of the M2 macrophage-related module in glioma through WGCNA analysis. The expression and prognosis analysis suggested that GPR65 was positively correlated with the malignancy and poor prognosis of glioma, and the heterogeneity analysis found that GPR65 was highly expressed in the vascular proliferation area of glioma, which matched the spatial expression characteristics of M2 macrophages. We further verified that GPR65 was highly expressed in macrophages but not tumor cells in the glioma microenvironment by single-cell data analysis and immunofluorescence. Most importantly, we found that inhibition of GPR65 was sufficient to reduce macrophages' polarization response to glioma cell and break the malignant cooperation with glioma cells. Our study reports the expression characteristics and malignant behavior of GPR65 in the glioma microenvironment, which provides a new alternative target of treatment to glioma microenvironment.


Asunto(s)
Neoplasias Encefálicas , Glioma , Receptores Acoplados a Proteínas G , Microambiente Tumoral , Humanos , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/genética , Línea Celular Tumoral , Glioma/patología , Glioma/genética , Macrófagos , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo
3.
Mol Cell Biochem ; 2023 Nov 29.
Artículo en Inglés | MEDLINE | ID: mdl-38019450

RESUMEN

Glioma is an intracranial tumor characterized by high mortality and recurrence rates. In the present study, the association of TRPM8 channel-associated factor 2 (TCAF2) in glioma was investigated using bioinformatics, showing significant relationships with age, WHO grade, IDH, and 1p/19q status, as well as being an independent predictor of prognosis. Immunohistochemistry of a glioma sample microarray showed markedly increased TCAF2 expression in glioblastoma relative to lower-grade glioma, with elevated expression predominating in the tumor center. Raised TCAF2 levels promote glioma cell migratory/invasion properties through the epithelial-to-mesenchymal transition-like (EMT-like) process, shown by Transwell and scratch assays and western blotting. It was further found that the effects of TCAF2 were mediated by the activation of STAT3. These results suggest that TCAF2 promotes glioma cell migration and invasion, rendering it a potential drug target in glioma therapy.

4.
Inorg Chem ; 62(29): 11436-11445, 2023 Jul 24.
Artículo en Inglés | MEDLINE | ID: mdl-37433112

RESUMEN

In this paper, we have thoroughly investigated the ORR mechanism of non-pyrolytic mono-1,10-phenanthroline-coordinated Cu2+ (Cu-N2 type) complexes and polymers by molecular dynamics and quantum mechanics calculation. In contrast to the complex-catalyzed ORR, which follows a direct four-electron pathway along intermediates of Cu(I)-Phen, the polymer-catalyzed ORR follows an indirect four-electron pathway by intermediates of Cu(II)-Phen. By analyzing the structure, spin population, electrostatic potential (ESP), and density of states, we confirmed that the higher ORR catalytic activity of the polymer is due to the conjugation effect of coplanar phenanthroline and Cu(II) in the planar reactants or at the base of the square-pyramidal intermediates. The conjugation effect allows the highest ESP to be located near the active center Cu(II), while the lower ESPs are distributed on the phenanthroline, which is very favorable for the reduction current. This will serve as a theoretical foundation for the development of new highly efficient ORR non-pyrolytic CuN2 polymer catalysts.

5.
Neurosurg Rev ; 46(1): 154, 2023 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-37380888

RESUMEN

Maintaining the integrity of crucial fiber tracts allows functional preservation and improved recovery in patients with glioma resection. Diffusion tensor imaging (DTI) and intraoperative subcortical mapping (ISM) are commonly required for pre- and intraoperative assessment of white matter fibers. This study investigated differences of clinical outcomes in glioma resection aided by DTI or ISM. A comprehensive literature retrieval of the PubMed and Embase databases identified several DTI or ISM studies in 2000-2022. Clinical data, including extent of resection (EOR) and postoperative neurological deficits, was collected and statistically analyzed. Heterogeneity was regressed by a random effect model and the Mann-Whitney U test was used to test statistical significance. Publication bias was assessed by Egger test. A total of 14 studies with a pooled cohort of 1837 patients were included. Patients undergoing DTI-navigated glioma surgery showed a higher rate of gross total resection (GTR) than ISM-assisted surgical resection (67.88%, [95% CI 0.55-0.79] vs. 45.73%, [95% CI 0.29-0.63], P = 0.032). The occurrence of early postoperative functional deficit (35.45%, [95% CI 0.13-0.61] vs. 35.60% [95% CI 0.20-0.53], P = 1.000), late postoperative functional deficit (6.00%, [95% CI 0.02-0.11] vs. 4.91% [95% CI 0.03-0.08], P = 1.000) and severe postoperative functional deficit (2.21%, [95% CI 0-0.08] vs. 5.93% [95% CI 0.01-0.16], P = 0.393) were similar between the DTI and ISM group, respectively. While DTI-navigation resulted in a higher rate of GTR, the occurrence of postoperative neurological deficits between DTI and ISM groups was comparable. Together, these data indicate that both techniques could safely facilitate glioma resection.


Asunto(s)
Glioma , Sustancia Blanca , Humanos , Imagen de Difusión Tensora , Bases de Datos Factuales , Glioma/diagnóstico por imagen , Glioma/cirugía , Periodo Posoperatorio
6.
Org Biomol Chem ; 20(33): 6566-6570, 2022 08 24.
Artículo en Inglés | MEDLINE | ID: mdl-35903979

RESUMEN

An efficient potassium persulfate-mediated radical addition of allenamides with diselenides was developed to create a workable route to 1,2-diselenide products. The reaction tolerates a wide spectrum of functional groups to deliver the products in good to excellent yields. Mechanistic investigations including a calculation study indicated that the radical cascade proceeds through a vinyl radical intermediate, which is formed via a selenium radical added to the terminal CC double bond of allenamides.


Asunto(s)
Compuestos de Organoselenio , Peroxidación de Lípido , Compuestos de Organoselenio/química , Compuestos de Potasio , Sulfatos
7.
Phys Chem Chem Phys ; 23(21): 12360-12370, 2021 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-34027522

RESUMEN

In this research, all the efforts, based on a series of molecular dynamics simulations on the interfacial process between VOC-contaminated air and acidic sulfate, were made to find how the structures and properties of VOCs are related to the formation of SOAs. The experimental fractional aerosol coefficients (FACs) were used to quantify the SOA formation and 14 VOC species were chosen based on the atmosphere inventory and the FAC magnitude. Finally, the quantitative relationship (QR) was found through the FAC as a function of the two variables the total valid interactions (Tg) and the diffusion coefficient (D), with R square 0.94. Meanwhile, the effect of water was explored and the QR was proved to be rational and reliable. The QR not only explained the SOA formation capacity of VOCs, but could also predict the SOA formation of new molecules.

8.
Exp Cell Res ; 389(1): 111893, 2020 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-32035133

RESUMEN

Compared with noninvasive tumor cells, glioma cells overexpress chemokine receptor type 4 (CXCR4), which exhibits significantly greater expression in invasive tumor cells than in noninvasive tumor cells. C-X-C motif chemokine ligand 12 (CXCL12, also known as stromal derived factor-1, SDF-1) and its cell surface receptor CXCR4 activate a signaling axis that induces the expression of membrane type-2 matrix metalloproteinase (MT2-MMP), which plays a pivotal role in the invasion and migration of various cancer cells; however, the specific mechanism involved in this is unclear. Recently, studies have shown that invadopodia can recruit and secrete related enzymes, such as matrix metalloproteinases (MMPs), to degrade the surrounding extracellular matrix (ECM), promoting the invasion and migration of tumor cells. Phosphorylated cortactin (pY421-cortactin) is required for the formation and maturation of invadopodia, but the upstream regulatory factors and kinases involved in phosphorylation have not been elucidated. In this study, we found that CXCL12/CXCR4 was capable of inducing glioma cell invadopodia formation, probably by regulating cortactin phosphorylation. The interaction of cortactin and Arg (also known as Abl-related nonreceptor tyrosine kinase, ABL2) in glioma cells was demonstrated. The silencing of Arg inhibited glioma cell invadopodia formation and invasion by blocking cortactin phosphorylation. Moreover, CXCL12 could not induce glioma cell invasion in Arg-knockdown glioma cells. Based on these results, it can be concluded that Arg mediates CXCL12/CXCR4-induced glioma cell invasion, and CXCL12/CXCR4 regulates invadopodia maturation through the Arg-cortactin pathway, which indicates that Arg could be a candidate therapeutic target to inhibit glioma cell invasion.


Asunto(s)
Neoplasias Encefálicas/patología , Quimiocina CXCL12/fisiología , Glioma/patología , Podosomas/fisiología , Proteínas Tirosina Quinasas/fisiología , Receptores CXCR4/fisiología , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Línea Celular Tumoral , Movimiento Celular/genética , Quimiocina CXCL12/metabolismo , Glioma/genética , Glioma/metabolismo , Humanos , Invasividad Neoplásica , Fosforilación , Podosomas/metabolismo , Procesamiento Proteico-Postraduccional , Receptores CXCR4/metabolismo , Transducción de Señal/genética
9.
J Cell Physiol ; 235(5): 4326-4334, 2020 05.
Artículo en Inglés | MEDLINE | ID: mdl-31609000

RESUMEN

In recent years, research on glioma immunotherapy have grown rapidly. However, the autoimmune-like side effects that are caused by blocking immunological checkpoints hinder their clinical application in gliomas currently. Galectin-9, a ligand for T-cell immunoglobulin mucin 3, has shed a new light on the treatment of malignant glioma. However, the potential mechanism of Galectin-9 is still under discussion. In this study, first, we methodically gathered 1,027 glioma patients with RNA-seq and 986 patients with survival data to explore the role and mechanism of Galectin-9 in gliomas. Second, we analyzed glioma samples from 50 patients in the Department of Neurosurgery, Tianjin Medical University General Hospital. Finally, we found that Galectin-9 was strongly upregulated in glioblastoma multiforme compared with normal brain tissues and lower-grade glioma. Patients with Galectin-9 overexpression had a significantly shorter overall survival. Moreover, the tissue microarray data displayed that the expression of Galectin-9 in the core of tumor is higher than that in the border and was correlated with the shorter survival in glioma patients. Galectin-9 is more highly expressed in the mesenchymal subtype of glioblastoma multiforme than in the other subtypes. Simultaneously, Galectin-9 was closely associated with the immune response and lymphocyte activation, especially T-cell activation. To further determine the underlying role of Galectin-9 in the immune response, we selected seven immune metagenes. Through cluster analysis and correlation analysis, we discovered that Galectin-9 was highly correlated with immune checkpoint molecules and M2 tumor-associated macrophages. In summary, Galectin-9 serves as a potential therapeutic target to treat glioblastoma multiforme.


Asunto(s)
Neoplasias Encefálicas/metabolismo , Galectinas/metabolismo , Glioma/metabolismo , Galectinas/genética , Regulación Neoplásica de la Expresión Génica/fisiología , Humanos , Transcriptoma , Regulación hacia Arriba
10.
Bioorg Chem ; 94: 103367, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31685258

RESUMEN

Ibrutinib (IBN), a first-in-class BTK-inhibitor, was approved by the FDA for the treatment of mantle cell lymphoma (MCL). Although IBN shows excellent performance as an anti-lymphoma agent, it has some undesirable side effects due to its off-target activities. Our studies yielded a novel series of 3-(6-phenoxypyridin-3-yl)-4-amine-1H-pyrazolo[3,4-d]pyrimidine derivatives capable of potent inhibition of Bruton's tyrosine kinase (BTK). Notably, compound 13e explained potent BTK inhibitory activity and could completely inhibit the phosphorylation of BTK and PLCγ2 in Z138 cells at low micromolar concentration. Compared with IBN, compound 13e improved anti-proliferative activities 3-40 folds in MCL cell lines with IC50 values lower than 1 µM. Low micromolar doses of 13e could induce strong cell apoptosis in Jeko-1 and Z138 cells. In addition, compound 13e showed greater BTK selectivity and higher stability in human liver microsomes than IBN and potential safety improvement for the treatment of MCL.


Asunto(s)
Agammaglobulinemia Tirosina Quinasa/antagonistas & inhibidores , Antineoplásicos/farmacología , Diseño de Fármacos , Linfoma de Células del Manto/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Pirimidinas/farmacología , Agammaglobulinemia Tirosina Quinasa/metabolismo , Antineoplásicos/síntesis química , Antineoplásicos/química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Humanos , Linfoma de Células del Manto/metabolismo , Linfoma de Células del Manto/patología , Modelos Moleculares , Estructura Molecular , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Pirimidinas/síntesis química , Pirimidinas/química , Transducción de Señal/efectos de los fármacos , Relación Estructura-Actividad
11.
J Cell Physiol ; 234(2): 1630-1642, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30159893

RESUMEN

Glioblastoma is the most common and lethal primary intracranial tumor. As the key regulator of tumor cell volume, sodium-potassium-chloride cotransporter 1 (NKCC1) expression increases along with the malignancy of the glioma, and NKCC1 has been implicated in glioblastoma invasion. However, little is known about the role of NKCC1 in the epithelial-mesenchymal transition-like process in gliomas. We noticed that aberrantly elevated expression of NKCC1 leads to changes in the shape, polarity, and adhesion of cells in glioma. Here, we investigated whether NKCC1 promotes an epithelial-mesenchymal transition (EMT)-like process in gliomas via the RhoA and Rac1 signaling pathways. Pharmacological inhibition and knockdown of NKCC1 both decrease the expressions of mesenchymal markers, such as N-cadherin, vimentin, and snail, whereas these treatments increase the expression of the epithelial marker E-cadherin. These findings indicate that NKCC1 promotes an EMT-like process in gliomas. The underlying mechanism is the facilitation of the binding of Rac1 and RhoA to GTP by NKCC1, which results in a significant enhancement of the EMT-like process. Specific inhibition or knockdown of NKCC1 both attenuate activated Rac1 and RhoA, and the pharmacological inhibitions of Rac1 and RhoA both impair the invasion and migration abilities of gliomas. Furthermore, we illustrated that NKCC1 knockdown abolished the dissemination and spread of glioma cells in a nude mouse intracranial model. These findings suggest that elevated NKCC1 activity acts in the regulation of an EMT-like process in gliomas, and thus provides a novel therapeutic strategy for targeting the invasiveness of gliomas, which might help to inhibit the spread of malignant intracranial tumors.


Asunto(s)
Neoplasias Encefálicas/enzimología , Transición Epitelial-Mesenquimal , Glioblastoma/enzimología , Miembro 2 de la Familia de Transportadores de Soluto 12/metabolismo , Proteína de Unión al GTP rac1/metabolismo , Proteína de Unión al GTP rhoA/metabolismo , Animales , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Movimiento Celular , Femenino , Regulación Neoplásica de la Expresión Génica , Glioblastoma/genética , Glioblastoma/patología , Humanos , Ratones Desnudos , Invasividad Neoplásica , Transducción de Señal , Miembro 2 de la Familia de Transportadores de Soluto 12/genética , Proteína de Unión al GTP rac1/genética , Proteína de Unión al GTP rhoA/genética
12.
Bioorg Med Chem ; 27(15): 3319-3327, 2019 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-31229421

RESUMEN

2,3-Indolinedione derivatives have been identified as a novel class of promising agents for cancer treatment. In this study, eighteen 2,3-indolinedione derivatives were designed and synthesized, and their anticancer activities against mantle cell lymphoma (MCL) cells were evaluated. Most of them exhibited significant antiproliferative activity against the tested cell lines, and compound K5 was the most potent (MCL cellular IC50 = 0.4-0.7 µM). Further, compound K5 could induce cell apoptosis and cell cycle arrest in G2/M phase. Additionally, the results of drug-likeness analysis demonstrated that these novel 2,3-indolinedione derivatives could have potential as novel treatment strategies for MCL.


Asunto(s)
Antineoplásicos/farmacología , Diseño de Fármacos , Indoles/farmacología , Linfoma de Células del Manto/tratamiento farmacológico , Antineoplásicos/síntesis química , Antineoplásicos/química , Apoptosis/efectos de los fármacos , Puntos de Control del Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Indoles/síntesis química , Indoles/química , Linfoma de Células del Manto/patología , Estructura Molecular , Relación Estructura-Actividad , Células Tumorales Cultivadas
13.
Cell Physiol Biochem ; 51(6): 2925-2937, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30580328

RESUMEN

BACKGROUND/AIMS: Jagged1 is the ligands of the Notch signaling and has been shown to promote glioma-initiating cells (GICs) in glioblastoma. The role of Jagged1 in GICs invasion and underlying molecular mechanisms remain unclear. METHODS: Survival data from R2 genomics analysis, the Cancer Genome Atlas (TCGA), the Chinese Glioma Genome Atlas (CGGA) and visualization platform database were used to evaluate the effects of Jagged1 on overall patient survival. we investigated Jagged1 induced the GICs cells' invasion by matrix degradation assays and Transwell cell invasion assays in vitro, then we further explored the underlying molecular mechanisms using Co-immunoprecipitation (co-IP) analysis. RESULTS: High expression of Jagged1 in human glioma was associated with poor survival. Clinical data analysis showed that the Jagged1 was positively correlated with NF-κB(p65). Jagged1-induced invasion of GICs cells through activation of NF-κB(p65) pathway. In vivo, knockdown of Jagged1 could suppress the tumorigenicity of GICs cells through NF-κB(p65) signaling. CONCLUSION: Insights gained from these findings suggest that Jagged1 plays an important oncogenic role in GICs malignancy by activation of NF-κB(p65) signaling, and Jagged1 could be employed as an effective therapeutic target for GICs.


Asunto(s)
Neoplasias Encefálicas/genética , Glioma/genética , Proteína Jagged-1/genética , Invasividad Neoplásica/genética , Transducción de Señal , Factor de Transcripción ReIA/metabolismo , Animales , Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patología , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica , Silenciador del Gen , Glioma/diagnóstico , Glioma/metabolismo , Glioma/patología , Humanos , Proteína Jagged-1/análisis , Proteína Jagged-1/metabolismo , Ratones Endogámicos BALB C , Ratones Desnudos , Invasividad Neoplásica/diagnóstico , Invasividad Neoplásica/patología , Pronóstico , Regulación hacia Arriba
14.
J Chem Phys ; 144(13): 134307, 2016 Apr 07.
Artículo en Inglés | MEDLINE | ID: mdl-27059570

RESUMEN

The structural, electronic, and optical properties of core-shell nanoclusters, (CdSe)(x)@(CdSe)(y) and their Zn-substituted complexes of x = 2-4 and y = 16-28, were studied with density functional theory calculations. The substitution was applied in the cores, the shells, and/or the whole clusters. All these clusters are characterized by their core-shell structures in which the core-shell interaction was found different from those in core or in shell, as reflected by their bondlengths, volumes, and binding energies. Moreover, the core and shell combine together to compose a new cluster with electronic and optical properties different from those of separated individuals, as reflected by their HOMO-LUMO gaps and optical absorptions. With the substitution of Cd by Zn, the structural, electronic, and optical properties of clusters change regularly. The binding energy increases with Zn content, attributed to the strong Zn-Se bonding. For the same core/shell, the structure with a CdSe shell/core has a narrower gap than that with a ZnSe shell/core. The optical absorption spectra also change accordingly with Zn substitution. The peaks blueshift with increasing Zn concentration, accompanying with shape variations in case large number of Cd atoms are substituted. Our calculations reveal the core-shell interaction and its influence on the electronic and optical properties of the core-shell clusters, suggesting a composition-structure-property relationship for the design of core-shell CdSe and ZnSe nanoclusters.

15.
Phys Chem Chem Phys ; 17(14): 9222-30, 2015 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-25761258

RESUMEN

Understanding the size-dependent structures and properties of ligand-capped nanoclusters in solvent is of particular interest for the design, synthesis and application of II-VI colloidal QDs. Using DFT and TDDFT calculations, we studied the structure and optical property evolution of the cysteine-capped (CdSe)N clusters of N = 1-10, 13, 16 and 19 in gas, toluene, water and alkaline aqueous solution, and made a comparison with their corresponding bare clusters. The cysteine binds with (CdSe)Nvia several patterns depending on the medium they exist in, affecting the cluster structures and in consequence their optical absorption. In general, the absorption bands of (CdSe)N blueshift when cysteine is added, and the shift varies with the interaction strength between the cluster and the ligand, and the dielectric constant of the solvent. However, bare clusters retain their size sensitivity, in particular the redshift trend with increasing cluster size, and some similarity was noted for the optical absorption of the bare and ligated clusters regardless of the gas or solvent media. Population analysis reveals that the excitations are mainly from orbitals distributing on the (CdSe)N part, while the ligand is negligibly involved in the excitations. This is an important feature for the II-VI QDs as biosensors with which the information of biomolecules is detected from the size dependent optical absorption or emission of the QDs other than the biomolecules.


Asunto(s)
Compuestos de Cadmio/química , Cisteína/química , Modelos Teóricos , Nanoestructuras/química , Nanotecnología , Fenómenos Ópticos , Puntos Cuánticos , Compuestos de Selenio/química , Ligandos , Solventes , Agua/química
16.
Phys Chem Chem Phys ; 17(27): 17864-71, 2015 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-26090584

RESUMEN

The introduction of multiple carbon rings is one of the common ways for graphene modification. Starting from warped C80H30 nanographene, which consists of a number of six- and seven-membered carbon rings (C6 and C7) centering at a five-membered carbon ring (C5), we explored the structure and property variations of its derivatives in which their C7 rings were gradually replaced with C6 rings. With reducing number of C7 rings, their curved boundary with the C6 rings becomes flat until a bowl-like structure is formed when all the C7 rings disappear. The optical absorption spectra vary accordingly. Both the α-bands and the maximum absorption bands in the visible region are related to the number and location of the C7 rings. Further analysis of the excited states of the C80H30 derivatives, as well as on the designed model systems, revealed that the C7 rings affect the electron excitations in two ways. In addition to their participation in electronic transitions, they control the composition of molecular orbitals that are involved in the excitations. The highest occupied molecular orbitals are mainly contributed by atoms on the C6 and C7 rings, while the lowest unoccupied molecular orbitals by atoms on the C5 and C6 rings. Our study sheds some light on how the multiple carbon rings affect the optical absorption of nanographenes and provides information for the preparation of nanographenes with tunable structural and optical properties.

17.
RSC Adv ; 14(24): 17184-17194, 2024 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-38808240

RESUMEN

Resulting from the solubility reduction of elemental sulfur during the development of high sulfur gas formations, sulfur deposition often occurs to reduce the gas production and threaten the safety of gas wells. Understanding the dissolution mechanism of elemental sulfur in natural gas is essential to reduce the risk caused by sulfur deposition. Because of the harsh conditions in the high-sulfur formations, it remains challenging to in situ characterize the dissolution-precipitation processes, making deficient the knowledge of sulfur dissolution mechanism. The dissolution of sulfur allotropes (SN, N = 2, 4, 6 and 8) in H2S, the main solvent of sulfur in natural gas, is studied in this work by means of first-principles calculations and molecular dynamics simulations. While S6 and S8 undergo physical interaction with H2S under the conditions corresponding to those at 1-6 km stratigraphic depths, S2 and S4 react with H2S and form stable polysulfides. Unravelling the mechanism would be helpful for understanding and controlling the sulfur deposition in high-sulfur gas development.

18.
ISME Commun ; 4(1): ycae001, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38371393

RESUMEN

Bacteria contribute to many physiological functions of coral holobionts, including responses to bleaching. The bacterial genus, Endozoicomonas, dominates the microbial flora of many coral species and its abundance appears to be correlated with coral bleaching. However, evidences for decoupling of bleaching and Endozoicomonas abundance changes have also been reported. In 2020, a severe bleaching event was recorded at reefs in Taiwan, providing a unique opportunity to re-examine bleaching-Endozoicomonas association using multiple stony corals in natural environments. In this study, we monitored tissue color and microbiome changes in three coral species (Montipora sp., Porites sp., and Stylophora pistillata) in Kenting National Park, following the bleaching event. All tagged Montipora sp. and Porites sp. recovered from bleaching within 1 year, while high mortality occurred in S. pistillata. Microbiome analysis found no correlation of Endozoicomonas relative abundance and bleaching severity during the sampling period, but found a stronger correlation when the month in which bleaching occurred was excluded. Moreover, Endozoicomonas abundance increased during recovery months in Montipora sp. and Porites sp., whereas in S. pistillata it was nearly depleted. These results suggest that Endozoicomonas abundance may represent a gauge of coral health and reflect recovery of some corals from stress. Interestingly, even though different Endozoicomonas strains predominated in the three corals, these Endozoicomonas strains were also shared among coral taxa. Meanwhile, several Endozoicomonas strains showed secondary emergence during coral recovery, suggesting possible symbiont switching in Endozoicomonas. These findings indicate that it may be possible to introduce Endozoicomonas to non-native coral hosts as a coral probiotic.

19.
Plant Mol Biol ; 81(4-5): 347-61, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23329372

RESUMEN

Germination followed by seedling growth constitutes two essential steps in the initiation of a new life cycle in plants, and in cereals, completion of these steps is regulated by sugar starvation and the hormone gibberellin. A calcium-dependent protein kinase 1 gene (OsCDPK1) was identified by differential screening of a cDNA library derived from sucrose-starved rice suspension cells. The expression of OsCDPK1 was found to be specifically activated by sucrose starvation among several stress conditions tested as well as activated transiently during post-germination seedling growth. In gain- and loss-of-function studies performed with transgenic rice overexpressing a constitutively active or RNA interference gene knockdown construct, respectively, OsCDPK1 was found to negatively regulate the expression of enzymes essential for GA biosynthesis. In contrast, OsCDPK1 activated the expression of a 14-3-3 protein, GF14c. Overexpression of either constitutively active OsCDPK1 or GF14c enhanced drought tolerance in transgenic rice seedlings. Hence, our studies demonstrated that OsCDPK1 transduces the post-germination Ca(2+) signal derived from sugar starvation and GA, refines the endogenous GA concentration and prevents drought stress injury, all essential functions to seedling development at the beginning of the life cycle in rice.


Asunto(s)
Proteínas 14-3-3/metabolismo , Adaptación Fisiológica , Carbohidratos/deficiencia , Giberelinas/biosíntesis , Oryza/enzimología , Proteínas Quinasas/biosíntesis , Plantones/fisiología , Adaptación Fisiológica/efectos de los fármacos , Adaptación Fisiológica/genética , Sequías , Inducción Enzimática/efectos de los fármacos , Retroalimentación Fisiológica/efectos de los fármacos , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica de las Plantas/efectos de los fármacos , Giberelinas/farmacología , Homocigoto , Modelos Biológicos , Tamaño de los Órganos/efectos de los fármacos , Oryza/efectos de los fármacos , Oryza/genética , Oryza/crecimiento & desarrollo , Proteínas de Plantas/metabolismo , Plantas Modificadas Genéticamente , Proteínas Quinasas/genética , Plantones/anatomía & histología , Plantones/efectos de los fármacos , Plantones/genética , Regulación hacia Arriba/efectos de los fármacos
20.
Phys Chem Chem Phys ; 15(24): 9742-51, 2013 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-23666551

RESUMEN

Poly(N-vinyl-2-pyrrolidone) (PVP) is often used to protect active Au clusters from coalescence. The influences of PVP on the O2 adsorption on Au32 clusters were investigated using density functional theory calculations. Various low-lying structures of O2:Au32 and O2:Au32:PVP complexes, in which the Au32 is either neutral or anionic and the O2 is either molecular or dissociative, were identified. The PVP influences were evaluated in terms of the changes in geometry, adsorption energy, charge redistribution, spin density, and density of states upon PVP pre-adsorption. Our calculations reveal that PVP weakly adsorbs on the cluster surface, with rather small changes in the structural, geometrical and electronic properties that are relevant to the O2 activation. The activity of neutral or anionic Au32 towards O2 is kept or slightly enhanced by PVP because of the cooperative adsorption of PVP and O2. This is the structural basis of choosing PVP as the protective ligand for Au clusters.

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