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1.
J Phys Chem A ; 127(31): 6400-6411, 2023 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-37498222

RESUMEN

Al-containing catalysts, e.g., Al(OTf)3, show good catalytic performance toward the conversion of cellulose to fructose in methanol solution. Here, we report the catalytic isomerization and alcoholysis mechanisms for the conversion of cellobiose to fructose at the PBE0/6-311++G(d,p), aug-cc-pVTZ theoretical level, combining the relevant experimental verifications of electrospray ionization mass spectrometry (ESI-MS), high-performance liquid chromatography (HPLC), and the attenuated total reflection-infrared (ATR-IR) spectra. From the alcoholysis of Al(OTf)3 in methanol solution, the catalytically active species involves both the [CH3OH2]+ Brønsted acid and the [Al(CH3O)(OTf)(CH3OH)4]+ Lewis acid. There are two reaction pathways, i.e., one through glucose (glycosidic bond cleavage followed by isomerization, w-G) and another through cellobiulose (isomerization followed by glycosidic bond cleavage, w-L). The Lewis acid ([Al(CH3O)(OTf)(CH3OH)4]+) is responsible for the aldose-ketose tautomerization, while the Brønsted acid ([CH3OH2]+) is in charge of ring-opening, ring-closure, and glycosidic bond cleavage. For both w-G and w-L, the rate-determining steps are related to the intramolecular [1,2]-H shift between C1-C2 for the aldose-ketose tautomerization catalyzed by the [Al(CH3O)(OTf)(CH3OH)4]+ species. The Lewis acid ([Al(CH3O)(OTf)(CH3OH)4]+) exhibits higher catalytic activity toward the aldose-ketose tautomerization of glycosyl-chain-glucose to glycosyl-chain-fructose than that of chain-glucose to chain-fructose. Besides, the Brønsted acid ([CH3OH2]+) shows higher catalytic activity toward the glycosidic bond cleavage of cellobiulose than that of cellobiose. Kinetically, the w-L pathway is predominant, whereas the w-G pathway is minor. The theoretically proposed mechanism has been experimentally testified. These insights may advance on the novel design of the catalytic system toward the conversion of cellulose to fructose.

2.
Phys Chem Chem Phys ; 25(12): 8507-8514, 2023 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-36883477

RESUMEN

In a solution of sorbitol (SBT) and Ga(OTf)3 compounds, the coordination of sorbitol (SBT) to [Ga(OTf)n]3-n (n = 0-3) has been investigated, using both ESI-MS spectra and density functional theory (DFT) calculations at the M06/6-311++g(d,p), aug-cc-pvtz level using a polarized continuum model (PCM-SMD). In sorbitol solution, the most stable conformer of sorbitol includes three intramolecular H-bonds, i.e., O2H⋯O4, O4H⋯O6, and O5H⋯O3. Through ESI-MS spectra, in a tetrahydrofuran solution of both SBT and Ga(OTf)3 compounds, five main species are observed, i.e., [Ga(SBT)]3+, [Ga(OTf)]2+, [Ga(SBT)2]3+, [Ga(OTf)(SBT)]2+, and [Ga(OTf)(SBT)2]2+. Through DFT calculations, in a solution of sorbitol (SBT) and Ga(OTf)3 compounds, the Ga3+ cation tends to form five six-coordination complexes, i.e., [Ga(η2O,O-OTf)3], [Ga(η3O2-O4-SBT)2]3+, [(η2O,O-OTf)Ga(η4O2-O5-SBT)]2+, [(η1O-OTf)(η2O2,O4-SBT)Ga(η3O3-O5-SBT)]2+, and [(η1O-OTf)(η2O,O-OTf)Ga(η3O3-O5-SBT)]+, which are in good agreement with the experimental observation of the ESI-MS spectra. For both [Ga(OTf)n]3-n (n = 1-3) and [Ga(SBT)m]3+ (m = 1, 2) complexes, the negative charge transfer from ligands to the Ga3+-center plays an important role in their stability, because of the strong polarization of the Ga3+ cation. For [Ga(OTf)n(SBT)m]3-n (n = 1, 2; m = 1, 2) complexes, the negative charge transfer from ligands to the Ga3+-center plays an essential role in their stability, accompanied by an electrostatic interaction between the Ga3+-center and ligands and/or spatial inclusion of ligands toward the Ga3+-center.

3.
Phys Chem Chem Phys ; 21(7): 3795-3804, 2019 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-30714064

RESUMEN

The selective removal of oxygen from 5-hydroxymethylfurfural (HMF) is challenging for the effective utilization of biomass. The catalytic mechanisms of palladium acetate toward the conversion of HMF to furfuryl alcohol (FFA), 5-methylfurfural (5-MF) and 2,5-dihydroxymethyl furan (DHMF) have been theoretically investigated. The decarbonylation of HMF to FFA includes (i) migratory extrusion, (ii) metal-acetate-co-assisted deprotonation, (iii) decarbonylation, (iv) metal-assisted deprotonation, and (v) migratory extrusion and catalyst regeneration. Both hydrogenation and deoxidation of HMF with HCOOH as the H-source involve (i) migratory extrusion, (ii) oxidative addition, (iii) reductive elimination, (iv) metal-assisted deprotonation, and (v) migratory extrusion and catalyst regeneration. The C-H bond cleavage is the crucial reaction step, in which the metal-acetate-co-assisted deprotonation is kinetically more preferable than the oxidative addition. Both FFA and DHMF are kinetically superior to 5-MF. In terms of selectivity, increasing the temperature is beneficial to decarbonylation and decreasing the temperature is advantageous to hydrogenation. The present finding provides molecular-level insight into the functions of both the metal-center and coordinated-ligand in the Pd(OAc)2 catalyst, which may drive the novel design of catalytic systems toward both decarbonylation and hydrogenation reactions.

4.
Genomics ; 109(5-6): 331-335, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28533192

RESUMEN

OBJECTIVE: Our study aims to explore the in vitro effects of reprogramming factors on the expressions of pluripotent genes and CD34 gene in HL-60 cells. METHODS: According to the construction of lentiviral vector LV-OSCK of reprogramming factors (Oct-4, Sox2, Klf4, c-Myc), 293T cells were transfected to detect virus titer. The endogenous pluripotent genes (Oct4, SOX2, c-Myc and Klf4) and CD34 mRNA and protein expressions were detected by AP staining, immunofluorescence staining, qRT-PCR and flow cytometry. RESULTS: Expressions of Oct4, SOX2, c-Myc and Klf4 were 0.220±0.013, 0.186±0.009, 0.287±0.015 and 0.153±0.007. These levels were significantly higher in the experimental group than the control and blank groups. CD34 protein expression in the experimental group was also discovered to be significantly higher than the other two groups. CONCLUSION: The reprogramming factors could increase the expressions of pluripotent genes and CD34 gene in HL-60 cells.


Asunto(s)
Antígenos CD34/genética , Proteínas de Unión al ADN/genética , Leucemia Promielocítica Aguda/genética , Regulación hacia Arriba , Antígenos CD34/metabolismo , Reprogramación Celular , Proteínas de Unión al ADN/metabolismo , Regulación Leucémica de la Expresión Génica , Células HEK293 , Células HL-60 , Humanos , Factor 4 Similar a Kruppel , Factores de Transcripción de Tipo Kruppel/genética , Factores de Transcripción de Tipo Kruppel/metabolismo , Lentivirus/fisiología , Leucemia Promielocítica Aguda/metabolismo , Factor 3 de Transcripción de Unión a Octámeros/genética , Factor 3 de Transcripción de Unión a Octámeros/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Factores de Transcripción SOXB1/genética , Factores de Transcripción SOXB1/metabolismo
5.
Cell Physiol Biochem ; 41(4): 1661-1674, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28359056

RESUMEN

OBJECTIVE: The present study aimed to establish an induced pluripotent stem cell (iPSC) line from acute myelogenous leukemia (AML) cells in vitro and identify their biological characteristics. METHODS: Cells from the AML-infiltrated skin from an M6 patient were infected with a lentivirus carrying OCT4, SOX2, KLF4 and C-MYC to induce iPSCs. The characteristics of the iPSCs were confirmed by alkaline phosphatase (ALP) staining. The proliferation ability of iPSCs was detected with a CCK-8 assay. The expression of pluripotency markers was measured by immunostaining, and the expression of stem cell-related genes was detected by qRT-PCR; distortion during the induction process was detected by karyotype analysis; the differentiation potential of iPSCs was determined by embryoid body-formation and teratoma-formation assays. ALP staining confirmed that these cells exhibited positive staining and had the characteristics of iPSCs. RESULTS: The CCK-8 assay showed that the iPSCs had the ability to proliferate. Immunostaining demonstrated that iPSC clones showed positive expression of NANOG, SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81. qRT-PCR results revealed that the mRNA expression of Nanog, Lin28, Cripto, FOX3, DNMT3b, DPPA2, and DPPA4 significantly increased in iPSCs. Karyotype analysis found no chromosome aberration in the iPSCs. The results of the embryoid body-formation and teratoma-formation assays indicated that the iPSCs had the potential to differentiate into all three germ layers. CONCLUSION: Our study provided evidence that an iPSC line derived from AML cells was successfully established.


Asunto(s)
Regulación Leucémica de la Expresión Génica , Células Madre Pluripotentes Inducidas/metabolismo , Leucemia Eritroblástica Aguda/metabolismo , Proteínas de Neoplasias/biosíntesis , Neoplasias Cutáneas/metabolismo , Factores de Transcripción/biosíntesis , Adulto , Humanos , Células Madre Pluripotentes Inducidas/patología , Factor 4 Similar a Kruppel , Leucemia Eritroblástica Aguda/genética , Leucemia Eritroblástica Aguda/patología , Masculino , Proteínas de Neoplasias/genética , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patología , Factores de Transcripción/genética
6.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 21(6): 1413-22, 2013 Dec.
Artículo en Chino | MEDLINE | ID: mdl-24370022

RESUMEN

This study was aimed to investigate the reversing effects of emodin on multidrug resistance (MDR) in resistant HL-60/ADR cells, and to explore the underlying mechanisms. The MTT assay was used to assess the chemoresistance of HL-60/ADR cells to emodin and 8 chemotherapeutic agents commonly used in clinic. The reversal effects of emodin on MDR of HL-60/ADR cells were also evaluated by MTT method. DNA ploidy analysis and DNA Ladder assay were used to detect apoptosis-induced effects on HL-60/ADR cells via the adriamycin (ADR) and emodin combination. The expression changes of the drug resistance-associated genes and proteins were detected by RT-PCR and Western Blot respectively. The intracellular accumulation and subcellular distribution of ADR and DNR were measured by flow cytometry and confocal laser scanning microscopy. The results showed that emodin inhibited HL-60/ADR cell proliferation with an average IC50 value of 24.09 ± 1.72 µmol/L, which was similar to that of the parental HL-60 cells (average IC50 = 23.18 ± 0.87 µmol/L). HL-60/ADR cells were resistant to a variety of chemotherapeutic agents, such as ADR, DNR, VP16, VCR,Ara-C, HHT, MTZ and THP. The reversal multiple were between 1.58 and 4.12 after the treatment with low concentration of emodin combined with the above mentioned different agents. The combination of ADR with emodin showed the best reversal effects, and the typical hypodiploid peak (apoptotic peak) and DNA ladder could be detected after the co-treatment.In addition, emodin down-regulated the mRNA and protein expression levels of MRP1, TOPOIIß, GST π and BCL-2. Furthermore, the addition of emodin enhanced ADR and DNR intracellular accumulation and subcellular distribution in HL-60/ADR cells in dose-dependent manner. It is concluded that the emodin shows reversing effects on the multidrug resistant HL-60/ADR cells, possibly via decreasing the expression levels of drug resistance-associated genes, increasing the intracellular accumulation of chemotherapeutic agents and activating the apoptosis pathway.


Asunto(s)
Antineoplásicos/farmacología , Resistencia a Múltiples Medicamentos/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Emodina/farmacología , Apoptosis , Doxorrubicina/farmacología , Células HL-60 , Humanos
7.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 21(1): 1-6, 2013 Feb.
Artículo en Chino | MEDLINE | ID: mdl-23484680

RESUMEN

This study was aimed to compare the expression level of eIF4E in patients with leukemia and normal controls, and to explore its role in leukemogenesis. White blood cells were collected in 76 leukemia patients and 10 healthy volunteers. The mRNA and protein expressions of eIF4E were detected by QT-PCR and Western blot in 39 cases of acute myeloid leukemia (AML), 15 cases of chronic myeloid leukemia (CML), 22 cases of acute lymphocytic leukemia (ALL) and 10 healthy volunteers as normal controls. The results demonstrated that compared with normal controls, the absolute expression levels of eIF4E mRNA increased in patients with AML, ALL and CML in blastic phase (P < 0.05), but had no significant change between groups of CML in chronic and accelerated phase although some increasing in group of CML in accelerated phase. The relative expression level of eIF4E mRNA had no significant change in AML, ALL, CML groups except the two subtypes of leukemia M4 and M5. Furthermore, the protein expression level in group of CML in accelerated phase and blastic phase and all acute leukemia patients including AML and ALL were higher than that in normal controls (P < 0.05). It is concluded that although its mRNA relative expressions had no significant change in most leukemia patients, the absolute expression level of eIF4E mRNA and its protein expression is up-regulated in most leukemia patients, which may play an important role in leukemogenesis, so the eIF4E may be a promising target for leukemia therapy and eIF4E-targeted therapy may be an option especially for the relapse and refractory leukemia.


Asunto(s)
Factor 4E Eucariótico de Iniciación/genética , Factor 4E Eucariótico de Iniciación/metabolismo , Leucemia/genética , Leucemia/metabolismo , Adolescente , Adulto , Anciano , Estudios de Casos y Controles , Femenino , Humanos , Leucemia/patología , Leucemia Mielógena Crónica BCR-ABL Positiva , Leucemia Mieloide Aguda , Masculino , Persona de Mediana Edad , Leucemia-Linfoma Linfoblástico de Células Precursoras , ARN Mensajero/genética , Adulto Joven
8.
Zhonghua Xue Ye Xue Za Zhi ; 26(6): 348-51, 2005 Jun.
Artículo en Chino | MEDLINE | ID: mdl-16185479

RESUMEN

OBJECTIVE: To investigate the effects of emodin on apoptosis induction and proliferation inhibition in human apoptosis and on c-myc protein and mRNA expression in human myeloid leukemia cell line HL-60 cells. METHODS: HL-60 cells were exposed to emodin at different dosages. Growth inhibition was detected by MTT assay and colony formation assay, and cell apoptosis by flow cytometry, TUNEL labeling method, DNA fragmentation and MitoCapture apoptosis detection. The expression of c-myc was detected by RT-PCR and Western-blot. RESULTS: Emodin remarkably inhibited the cell proliferation, with an IC(50) value of 20 micromol/L. HL-60 cells apoptosis could be efficiently induced by emodin in a dose dependent manner. The c-myc protein and mRNA expressions on HL-60 cells were decreased after emodin treatment. CONCLUSION: Emodin could efficiently induce growth inhibition and apoptosis in HL-60 cells. c-myc may be involved in this process.


Asunto(s)
Apoptosis/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Emodina/farmacología , Proteínas Proto-Oncogénicas c-myc/fisiología , Células HL-60/efectos de los fármacos , Humanos , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , ARN Mensajero/genética
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