Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 80
Filtrar
1.
Biochemistry ; 2024 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-38334276

RESUMO

RNA G-quadruplex (rG4) structures can influence the fate and functions of mRNAs, especially the translation process. The presence of rG4 structures in 5'-untranslated regions (5'-UTRs) of mRNAs generally represses translation. However, rG4 structures can also promote internal ribosome entry site (IRES)-mediated translation as one of its determinants. Here, we report the identification of an evolutionary conserved rG4-forming sequence motif at the extreme 5'-end of the unusually long 5'-UTR (1.7 kb) in the transcript of human cIAP1 gene encoding the cellular inhibitor of apoptosis protein-1 that promotes cell survival by suppressing apoptosis and is overexpressed in various cancer cells. Expectedly, NMR study, CD spectroscopy, and UV melting assay confirm the formation of a potassium ion-dependent intramolecular and parallel rG4 structure at the sequence stretch. Moreover, the G4-RNA-specific precipitation using biotin-linked biomimetic BioCyTASQ validates the formation of the rG4 structure in the cIAP1 5'-UTR in cells. Interestingly, disruption of the rG4 structure in the cIAP1 5'-UTR results in a dramatic reduction in translation of the downstream luciferase reporter in cells, suggesting a translation-promoting effect of the rG4 structure, contrary to many earlier reports. Furthermore, enhancement of translation by the cIAP1 rG4 structure occurs in an IRES-independent manner.

2.
J Cell Mol Med ; 28(7): e18150, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38494866

RESUMO

The anti-apoptotic proteins, Bcl-2 and Survivin, are consistently overexpressed in numerous human malignancies, notably in colorectal cancer. 2,4-Di-tert-butylphenol (2,4-DTBP) is a naturally occurring phenolic compound known for its diverse biological activities, including anti-cancer properties. The mechanism behind 2,4-DTBP-induced inhibition of cell proliferation and apoptosis in human colorectal cancer cells, specifically regarding Bcl-2 and Survivin, remains to be elucidated. In this study, we employed both in silico and in vitro methodologies to underpin this interaction at the molecular level. Molecular docking demonstrated a substantial binding affinity of 2,4-DTBP towards Bcl-2 (ΔG = -9.8 kcal/mol) and Survivin (ΔG = -5.6 kcal/mol), suggesting a potential inhibitory effect. Further, molecular dynamic simulations complemented by MM-GBSA calculations confirmed the significant binding of 2,4-DTBP with Bcl-2 (dGbind = -54.85 ± 6.79 kcal/mol) and Survivin (dGbind = -32.36 ± 1.29 kcal/mol). In vitro assays using HCT116 colorectal cancer cells revealed that 2,4-DTBP inhibited proliferation and promoted apoptosis in both a dose- and time-dependent manner. Fluorescence imaging and scanning electron microscopy illustrated the classical features associated with apoptosis upon 2,4-DTBP exposure. Cell cycle analysis through flow cytometry highlighted a G1 phase arrest and apoptosis assay demonstrated increased apoptotic cell population. Notably, western blotting results indicated a decreased expression of Bcl-2 and Survivin post-treatment. Considering the cytoprotective roles of Bcl-2 and Survivin through the inhibition of mitochondrial dysfunction, our findings of disrupted mitochondrial bioenergetics, characterized by reduced ATP production and oxygen consumption, further accentuate the functional impairment of these proteins. Overall, the integration of in silico and in vitro data suggests that 2,4-DTBP holds promise as a therapeutic agent targeting Bcl-2 and Survivin in colorectal cancer.


Assuntos
Neoplasias Colorretais , Fenóis , Humanos , Survivina , Simulação de Acoplamento Molecular , Proliferação de Células
3.
Microb Pathog ; 186: 106472, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38048836

RESUMO

Eggplant wilt, despite emerging as a severe disease in India, the etiology must be better studied for its species' complexity and variability. The identity of fungal isolates associated with eggplants of India was established morphologically followed by sequencing and phylogenetic analysis. Three species, Fusarium falciforme, Fusarium incarnatum and Fusarium proliferatum, were observed for the first time in India. The isolates were tested for pathogenicity. Though all of them were pathogenic, the isolates displayed varying degrees of virulence. In further studies, the genetic relatedness of the isolates for virulence was assessed with candidate avirulent (SIX effectors), virulent (Fow1 and Fow2) and SSR markers. The SIX effector genes could not delineate the virulent isolates and were expressed in some non-F. oxysporum isolates for the first time. Likewise, the virulent genes, Fow1 for expression across the isolates and Fow2 for random expression across the isolates, were unsuitable markers for identifying the virulent groups. Hence, the F. oxysporum and F. solani isolates were genotyped with SSR markers. Though the clustering did not correlate with their virulence levels, the dendrogram grouping revealed variability among the F. oxysporum and F. solani isolates. This study concludes that although multiple species of Fusarium are associated with eggplant wilt in India, only F. oxysporum and F. solani are widespread in the surveyed areas. Though the three markers could not delineate the race specificity of the isolates, only the SSR makers could identify the genetic variability and hence, would help screen eggplant germplasm for fusarium wilt resistance.


Assuntos
Fusarium , Solanum melongena , Virulência/genética , Filogenia , Genótipo , Doenças das Plantas/microbiologia
4.
J Microencapsul ; 41(5): 390-401, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38945157

RESUMO

Green-synthesis of biodegradable polymeric curcumin-nanoparticles using affordable biodegradable polymers to enhance curcumin's solubility and anti-oxidative potential. The curcumin-nanoparticle was prepared based on the ionic-interaction method without using any chemical surfactants, and the particle-size, zeta-potential, surface-morphology, entrapmentefficiency, and in-vitro drug release study were used to optimise the formulation. The antioxidant activity was investigated using H2DCFDA staining in the zebrafish (Danio rerio) model. The mean-diameter of blank nanoparticles was 178.2 nm (±4.69), and that of curcuminnanoparticles was about 227.7 nm (±10.4), with a PDI value of 0.312 (±0.023) and 0.360 (±0.02). The encapsulation-efficacy was found to be 34% (±1.8), with significantly reduced oxidative-stress and toxicity (∼5 times) in the zebrafish model compared to standard curcumin. The results suggested that the current way of encapsulating curcumin using affordable, biodegradable, natural polymers could be a better approach to enhancing curcumin's water solubility and bioactivity, which could further be translated into potential therapeutics.


Assuntos
Antioxidantes , Quitosana , Curcumina , Química Verde , Goma Arábica , Nanopartículas , Peixe-Zebra , Animais , Curcumina/farmacologia , Curcumina/química , Curcumina/administração & dosagem , Curcumina/farmacocinética , Nanopartículas/química , Antioxidantes/farmacologia , Antioxidantes/química , Antioxidantes/administração & dosagem , Quitosana/química , Goma Arábica/química , Portadores de Fármacos/química , Liberação Controlada de Fármacos , Solubilidade , Estresse Oxidativo/efeitos dos fármacos , Tamanho da Partícula
5.
Biomacromolecules ; 24(3): 1103-1110, 2023 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-36749347

RESUMO

Exploiting cellulose nanocrystals' high aspect ratio and tailorable surface for immunological biosensors has been hindered by the relatively limited research on using commonly available sulfated cellulose nanocrystals (CNCs) for antibody immobilization and by the low hydrolytic stability of dried assemblies produced from sulfated CNCs. Herein, we report a reaction scheme that enables both hydrolytic stability and antibody immobilization through 3-aminopropyl-triethoxysilane and glutaric anhydride chemistry. Immobilization was demonstrated using three model antibodies used in the detection of the cancer biomarkers: alpha-fetoprotein, prostate-specific antigen, and carcinoembryonic antigen. Thermogravimetric analysis coupled with Fourier-transform infrared spectroscopy provided evidence of CNC modification. Quartz crystal microbalance with dissipation monitoring was used to monitor binding during each step of the immobilization scheme as well as binding of the corresponding antigens. The general reaction scheme was tested using both aqueous CNC dispersions and CNC films. Film modification is slightly simpler as it avoids centrifugation and washing steps. However, modifying the dispersed CNCs provides access to their entire surface area and results in a greater capacity for antigen binding.


Assuntos
Celulose , Nanopartículas , Celulose/química , Sulfatos , Anticorpos , Nanopartículas/química
6.
Mol Biol Rep ; 50(4): 3451-3458, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36757552

RESUMO

BACKGROUND: δ-tubulin - a member of tubulin superfamily, is found in a subset of eukaryotes including human where it has a role in centriole maturation. The mutation in the gene results in a disorganized microtubule triplet arrangement leading to formation of defective centriole. Since centriole maturation is a periodic event, it will be interesting to see if δ-tubulin is also regulated in a cell cycle dependent manner. METHODS AND RESULTS: In this regard we show that the abundance of δ-tubulin mRNA remains unchanged throughout the cell cycle. However, the protein level varies periodically with a significantly higher expression in S-phase, implying regulation at the level of translation. Sequence analysis establishes the presence of a 90-base long conserved region, including a consensus motif of nine residues in the 5´-untranslated region (5´-UTR) of δ-tubulin transcript. The deletion analysis of the conserved region using luciferase reporter assay system confirms its strong inhibitory effect on translation. Interestingly, microtubule associated protein 4 (MAP4) is found to interact specifically with the 90-base long conserved region in the 5´-UTR and possibly responsible, at least partially, for the translation inhibitory activity of the UTR. Remarkably, MAP4 interacts with δ-tubulin in a periodic manner at protein level also. CONCLUSION: The results reported here show that δ-tubulin protein expression is regulated at posttranscriptional level and strongly suggest the role of MAP4 in modulation of both abundance and function of δ-tubulin.


Assuntos
Proteínas Associadas aos Microtúbulos , Tubulina (Proteína) , Humanos , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo , Regiões 5' não Traduzidas/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Ciclo Celular , Biossíntese de Proteínas/genética
7.
Alcohol Clin Exp Res ; 45(7): 1359-1369, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34120346

RESUMO

BACKGROUND: Prenatal exposure to alcohol leads to a greater incidence of many cardiovascular-related diseases, presumably via a mechanism that may involve increased oxidative stress. An agonist of peroxisome proliferator-activated receptor gamma (PPARγ; rosiglitazone) has been shown to suppress alcohol-induced neuroinflammation and oxidative stress. The goal of this study was to determine whether acute and chronic treatment with rosiglitazone could restore or prevent impaired nitric oxide synthase (NOS)-dependent responses of cerebral arterioles in male and female adult (14-16 weeks old) rats exposed to alcohol in utero. METHODS: We fed Sprague-Dawley dams a liquid diet with or without 3% ethanol for the duration of their pregnancy (21-23 days). In the first series of studies, we examined the reactivity of cerebral arterioles to eNOS- (ADP), nNOS-dependent (NMDA), and NOS-independent agonists in male and female adult rats before and during acute (1 hour) topical application of rosiglitazone (1 µM). In a second series of studies, we examined the influence of chronic treatment with rosiglitazone (3 mg/kg/day in drinking water for 2-3 weeks) on the responses of cerebral arterioles in male and female adult rats exposed to alcohol in utero. RESULTS: We found that in utero exposure to alcohol similarly reduced responses of cerebral arterioles to ADP and NMDA, but not to nitroglycerin in male and female adult rats. In addition, acute treatment of the male and female adult rats with rosiglitazone similarly restored this impairment in cerebral vascular function to that observed in controls. We also found that chronic treatment with rosiglitazone prevented impaired vascular function in male and female adult rats that were exposed to alcohol in utero. CONCLUSIONS: PPARγ activation may be an effective and relevant treatment to reverse or prevent cerebral vascular abnormalities associated with prenatal exposure to alcohol.


Assuntos
Arteríolas/efeitos dos fármacos , Encéfalo/irrigação sanguínea , Etanol/administração & dosagem , Óxido Nítrico Sintase/fisiologia , Efeitos Tardios da Exposição Pré-Natal , Rosiglitazona/administração & dosagem , Animais , Arteríolas/patologia , Arteríolas/fisiopatologia , Transtornos Cerebrovasculares/induzido quimicamente , Transtornos Cerebrovasculares/fisiopatologia , Transtornos Cerebrovasculares/prevenção & controle , Etanol/efeitos adversos , Feminino , Masculino , Estresse Oxidativo/efeitos dos fármacos , PPAR gama/agonistas , Gravidez , Ratos , Ratos Sprague-Dawley , Superóxidos/análise
8.
Langmuir ; 36(18): 4975-4984, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32308003

RESUMO

A Landau-de Gennes formulation coupled with a mass-transfer equation was used to track the evaporation front and the development of chiral microstructures during the casting of sulfuric acid-hydrolyzed cellulose nanocrystal (CNC) films. These simulations are compared to thin-film casting experiments that used analogous processing parameters and environments. The results show that the initial concentration, chiral strength, surface anchoring, speed of drying, and the influence of initial shear alignment all affect the uniformity of the microstructure and the orientation of the chiral director. In this report, we aim to show that under optimal casting conditions, the lateral size of planar microstructural domains that exhibit uniform selective reflection can be achieved on the order of millimeters.

9.
Anesthesiology ; 133(6): 1214-1222, 2020 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-32960954

RESUMO

BACKGROUND: The Hypotension Prediction Index is a commercially available algorithm, based on arterial waveform features, that predicts hypotension defined as mean arterial pressure less than 65 mmHg for at least 1 min. We therefore tested the primary hypothesis that index guidance reduces the duration and severity of hypotension during noncardiac surgery. METHODS: We enrolled adults having moderate- or high-risk noncardiac surgery with invasive arterial pressure monitoring. Participating patients were randomized to hemodynamic management with or without index guidance. Clinicians caring for patients assigned to guidance were alerted when the index exceeded 85 (range, 0 to 100) and a treatment algorithm based on advanced hemodynamic parameters suggested vasopressor administration, fluid administration, inotrope administration, or observation. Primary outcome was the amount of hypotension, defined as time-weighted average mean arterial pressure less than 65 mmHg. Secondary outcomes were time-weighted mean pressures less than 60 and 55 mmHg. RESULTS: Among 214 enrolled patients, guidance was provided for 105 (49%) patients randomly assigned to the index guidance group. The median (first quartile, third quartile) time-weighted average mean arterial pressure less than 65 mmHg was 0.14 (0.03, 0.37) in guided patients versus 0.14 (0.03, 0.39) mmHg in unguided patients: median difference (95% CI) of 0 (-0.03 to 0.04), P = 0.757. Index guidance therefore did not reduce amount of hypotension less than 65 mmHg, nor did it reduce hypotension less than 60 or 55 mmHg. Post hoc, guidance was associated with less hypotension when analysis was restricted to episodes during which clinicians intervened. CONCLUSIONS: In this pilot trial, index guidance did not reduce the amount of intraoperative hypotension. Half of the alerts were not followed by treatment, presumably due to short warning time, complex treatment algorithm, or clinicians ignoring the alert. In the future we plan to use a lower index alert threshold and a simpler treatment algorithm that emphasizes prompt treatment.


Assuntos
Determinação da Pressão Arterial/métodos , Hipotensão/prevenção & controle , Monitorização Intraoperatória/métodos , Procedimentos Cirúrgicos Operatórios , Idoso , Algoritmos , Pressão Arterial/fisiologia , Feminino , Hemodinâmica , Humanos , Hipotensão/diagnóstico , Hipotensão/fisiopatologia , Masculino , Projetos Piloto , Valor Preditivo dos Testes , Risco , Índice de Gravidade de Doença , Tempo
10.
Anesthesiology ; 132(1): 121-130, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31651439

RESUMO

BACKGROUND: Low 25-hydroxyvitamin D is associated with cardiovascular, renal, and infectious risks. Postsurgical patients are susceptible to similar complications, but whether vitamin D deficiency contributes to postoperative complications remains unclear. We tested whether low preoperative vitamin D is associated with cardiovascular events within 30 days after noncardiac surgery. METHODS: We evaluated a subset of patients enrolled in the biobank substudy of the Vascular events In noncardiac Surgery patIents cOhort evaluatioN (VISION) study, who were at least 45 yr with at least an overnight hospitalization. Blood was collected preoperatively, and 25-hydroxyvitamin D was measured in stored samples. The primary outcome was the composite of cardiovascular events (death, myocardial injury, nonfatal cardiac arrest, stroke, congestive heart failure) within 30 postoperative days. Secondary outcomes were kidney injury and infectious complications. RESULTS: A total of 3,851 participants were eligible for analysis. Preoperative 25-hydroxyvitamin D concentration was 70 ± 30 nmol/l, and 62% of patients were vitamin D deficient. Overall, 26 (0.7%) patients died, 41 (1.1%) had congestive heart failure or nonfatal cardiac arrest, 540 (14%) had myocardial injury, and 15 (0.4%) had strokes. Preoperative vitamin D concentration was not associated with the primary outcome (average relative effect odds ratio [95% CI]: 0.93 [0.85, 1.01] per 10 nmol/l increase in preoperative vitamin D, P = 0.095). However, it was associated with postoperative infection (average relative effect odds ratio [95% CI]: 0.94 [0.90, 0.98] per 10 nmol/l increase in preoperative vitamin D, P adjusted value = 0.005) and kidney function (estimated mean change in postoperative estimated glomerular filtration rate [95% CI]: 0.29 [0.11, 0.48] ml min 1.73 m per 10 nmol/l increase in preoperative vitamin D, P adjusted value = 0.004). CONCLUSIONS: Preoperative vitamin D was not associated with a composite of postoperative 30-day cardiac outcomes. However, there was a significant association between vitamin D deficiency and a composite of infectious complications and decreased kidney function. While renal effects were not clinically meaningful, the effect of vitamin D supplementation on infectious complications requires further study.


Assuntos
Doenças Transmissíveis/epidemiologia , Cardiopatias/epidemiologia , Nefropatias/epidemiologia , Complicações Pós-Operatórias/epidemiologia , Período Pré-Operatório , Deficiência de Vitamina D/sangue , Deficiência de Vitamina D/epidemiologia , Idoso , Doenças Transmissíveis/sangue , Comorbidade , Feminino , Cardiopatias/sangue , Humanos , Nefropatias/sangue , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/sangue , Vitamina D/análogos & derivados , Vitamina D/sangue
11.
Nano Lett ; 19(10): 7191-7200, 2019 10 09.
Artigo em Inglês | MEDLINE | ID: mdl-31507187

RESUMO

Developing low-weight, frugal, and sustainable power sources for resource-limited settings appears to be a challenging proposition for the advancement of next-generation sensing devices and beyond. Here, we report the use of centimeter-sized simple wet fabric pieces for electrical power generation by deploying the interplay of a spontaneously induced ionic motion across fabric nanopores due to capillary action and simultaneous water evaporation by drawing thermal energy from the ambient. Unlike other reported devices with similar functionalities, our arrangement does not necessitate any input mechanical energy or complex topographical structures to be embedded in the substrate. A single device is capable of generating a sustainable open circuit potential up to ∼700 mV, which is further scaled up to ∼12 V with small-scale multiplexing (i.e., deploying around 40 numbers of fabric channels simultaneously). The device is able to charge a commercial supercapacitor of ∼0.1 F which can power a white light-emitting diode for more than 1 h. This suffices in establishing an inherent capability of functionalizing self-powered electronic devices and also to be potentially harnessed for enhanced power generation with feasible up-scaling.

12.
J Food Sci Technol ; 57(1): 293-300, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31975732

RESUMO

The present study was aimed to analyse bioactive compounds (total phenolics, ascorbic acid and sinigrin) and antioxidant activity in 14 mid-early cauliflower genotypes. Significant differences (pb 0.05) were observed among the genotypes for all bioactive compounds and antioxidant activity. Total phenolics content of curd were ranged from 20.36 to 48.93 mg gallic acid equivalent (GAE) 100 g-1 fresh weight (FW) which showed 2.5 times variation. The ascorbic acid content was maximum in DC522 (88.53 mg 100 g-1 FW) followed by Pusa Sharad (65.64 mg 100 g-1 FW) while minimum in DC310 (39.62 65.64 mg 100 g-1 FW). Wide variation was observed for cupric reducing antioxidant capacity and ferric reducing antioxidant power ranging from 9.04 to 20.83 mg GAE 100 g-1 FW and 13.11 to 26.31 mg GAE 100 g-1 FW, respectively. Sinigrin was found to be highest in DC306 (39.50 µmol 100 g-1 FW) for leaf and in DC326 (36.93 µmol 100 g-1 FW) for curd sample. The cauliflower genotypes were classified based on chemometric approaches namely principal component analysis (PCA) and agglomerative hierarchical clustering (AHC). The first two principal components (PC1 and PC2) explained 50.62% and 23.28% of total variance, respectively. The AHC as revealed by heat map classified cauliflower genotypes into four main groups based on measured traits. The information is useful for developing varieties and/or hybrids rich in bioactive compounds and antioxidant activity.

13.
Anal Chem ; 90(21): 12832-12839, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30289244

RESUMO

A novel analytical methodology based on correlated optical and electroanalytical measurements was developed to probe electrocatalytic reactions at individual nanoparticles (NPs) with well-defined geometries. The developed methodology, Optically Targeted ElectroChemical Cell Microscopy (OTECCM), relies on a combination of optical hyperspectral imaging, to locate individual NPs and provide structural information, and Scanning ElectroChemical Cell Microscopy (SECCM), to provide direct information on the electrochemical behavior of the same NPs. This complementary strategy allows for SECCM measurements to be carried out in a "targeted" fashion, offering significant throughput advantages over conventional, scanning-based approaches. The developed methodology was applied to study the electrocatalytic oxidation of hydrazine at individual Au nanorods (NRs). Correlated electron microscopy investigations were carried out to conclusively demonstrate the ability of the proposed methodology to probe electrochemical reactions at individual NRs. A wide variety in behavior of the individual NRs was observed, with surface reactions at Au playing a prominent role in the observed response. In situ spectroscopic investigations at individual NRs suggest surface restructuring and/or residual ligand desorption leads to significant changes in catalytic activity over time. Results from the correlated electron microscopy investigations as well as the statistical analyses of data obtained for hundreds of individual nanostructures suggest that the gross geometry of a NR is a poor predictor of its electrocatalytic performance.


Assuntos
Técnicas Eletroquímicas/métodos , Ouro/química , Hidrazinas/química , Microscopia/métodos , Nanotubos/química , Catálise , Oxirredução
14.
Langmuir ; 34(44): 13274-13282, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30301352

RESUMO

A Landau-de Gennes formulation was implemented in dynamic finite element simulations to compare with postshear relaxation experiments that were conducted on cholesteric cellulose nanocrystal (CNC) dispersions. Our study focused on the microstructural reassembly of CNCs in lyotropic dispersions as parameters such as chiral strength and gap confinement were varied. Our simulation results show that homeotropic and/or more complicated three-dimensional helical configurations are possible, depending on the choice of these parameters. We also observed how dynamic banding patterns develop into the hierarchical microstructures that are characterized by an equilibrium pitch length in both the experiments and simulations. This work has immediate relevance for cellulose nanocrystal dispersion processing and provides new insight into fluid phase ordering for tailorable optical properties.

15.
Langmuir ; 34(4): 1447-1456, 2018 01 30.
Artigo em Inglês | MEDLINE | ID: mdl-29281292

RESUMO

Bioactive nanomaterials, namely: ruthenium hydrous oxide (or ruthenium oxy-hydroxide), RuOx(OH)y and also a surface-conjugated novel material of the same within the template of an amino acid molecule, l-cysteine, have been studied. These compounds have been prepared through a simple wet chemical route, under physiological conditions, such that they could be suitably used in anticancer applications. Several physical methods were used for the nanomaterial characterization, e.g.: thermal analysis of the as prepared ruthenium hydrous oxide by differential scanning calorimetry (DSC) followed by thermal gravimetric analysis (TGA). This confirms that the material is a precursor for anhydrous nanocrystalline ruthenium oxide (RuO2), as is affirmed by powder X-ray diffraction pattern. Also, optical spectroscopic absorption (UV-vis and FT-IR) study of these nanoparticles (NPs) to ascertain their surface conjugation with l-cysteine have been performed. Besides these, surface morphology of the NPs were studied by field emission scanning electron microscopy (FE-SEM) along with their elemental purity check through energy dispersive X-ray analysis (EDX). Their surface chemical microenvironments were examined by X-ray photo electron spectroscopy (XPS). The hydrodynamic size of the prepared NPs were measured through dynamic light scattering (DLS) studies. Further, biological consequences of these NPs on cancerous HeLa cells and their cytotoxicity effects have been reported with MTT assay, such an application has not been reported so far.


Assuntos
Antineoplásicos/química , Cisteína/química , Nanopartículas Metálicas/química , Compostos de Rutênio/química , Varredura Diferencial de Calorimetria , Difusão Dinâmica da Luz , Células HeLa , Humanos , Microscopia Eletrônica de Varredura , Difração de Raios X
16.
Nucleic Acids Res ; 44(16): 7755-65, 2016 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-27402161

RESUMO

The Ku protein, a heterodimer of Ku70 and Ku80, binds to chromosomal replication origins maximally at G1-phase and plays an essential role in assembly of origin recognition complex. However, the mechanism regulating such a critical periodic activity of Ku remained unknown. Here, we establish human Ku70 as a novel target of cyclin B1-Cdk1, which phosphorylates it in a Cy-motif dependent manner. Interestingly, cyclin E1- and A2-Cdk2 also phosphorylate Ku70, and as a result, the protein remains in a phosphorylated state during S-M phases of cell cycle. Intriguingly, the phosphorylation of Ku70 by cyclin-Cdks abolishes the interaction of Ku protein with replication origin due to disruption of the dimer. Furthermore, Ku70 is dephosphorylated in G1-phase, when Ku interacts with replication origin maximally. Strikingly, the over-expression of Ku70 with non-phosphorylable Cdk targets enhances the episomal replication of Ors8 origin and induces rereplication in HeLa cells, substantiating a preventive role of Ku phosphorylation in premature and untimely licensing of replication origin. Therefore, periodic phosphorylation of Ku70 by cyclin-Cdks prevents the interaction of Ku with replication origin after initiation events in S-phase and the dephosphorylation at the end of mitosis facilitates its participation in pre-replication complex formation.


Assuntos
Ciclo Celular , Quinases Ciclina-Dependentes/metabolismo , Replicação do DNA , Autoantígeno Ku/metabolismo , Multimerização Proteica , Subunidades Proteicas/metabolismo , Ciclina B1/metabolismo , Células HEK293 , Células HeLa , Humanos , Mitose , Modelos Biológicos , Mutação/genética , Fosforilação , Ligação Proteica , Origem de Replicação
17.
Soft Matter ; 13(45): 8451-8462, 2017 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-29087424

RESUMO

Cellulose nanocrystals (CNC) have been studied as nanostructured building blocks for functional materials and function as a model nanomaterial mesogen for cholesteric (chiral nematic) liquid crystalline phases. In this study, both rheology and small angle neutron scattering (RheoSANS) were used to measure changes in flow-oriented order parameter and viscosity as a function of shear rate for isotropic, biphasic, liquid crystalline, and gel dispersions of CNC in deuterium oxide (D2O). In contrast to plots of viscosity versus shear rate, the order parameter trends showed three distinct rheological regions over a range of concentrations. This finding is significant because the existence of three rheological regions as a function of shear rate is a long-standing signature of liquid crystalline phases composed of rod-like polymers, but observing this trend has been elusive for high-concentration dispersions of anisotropic nanomaterials. The results of this work are valuable for guiding the development of processing methodologies for producing ordered materials from CNC dispersions and the broader class of chiral nanomaterial mesogens.

18.
Chemphyschem ; 17(2): 270-7, 2016 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-26563628

RESUMO

Drug sensitization with various inorganic nanoparticles (NPs) has proved to be a promising and an emergent concept in the field of nanomedicine. Rose bengal (RB), a notable photosensitizer, triggers the formation of reactive oxygen species under green-light irradiation, and consequently, it induces cytotoxicity and cell death. In the present study, the effect of photoinduced dynamics of RB upon complexation with semiconductor zinc oxide NPs is explored. To accomplish this, we successfully synthesized nanohybrids of RB with ZnO NPs with a particle size of 24 nm and optically characterized them. The uniform size and integrity of the particles were confirmed by high-resolution transmission electron microscopy. UV/Vis absorption and steady-state fluorescence studies reveal the formation of the nanohybrids. ultrafast picosecond-resolved fluorescence studies of RB-ZnO nanohybrids demonstrate an efficient electron transfer from the photoexcited drug to the semiconductor NPs. Picosecond-resolved Förster resonance energy transfer from ZnO NPs to RB unravel the proximity of the drug to the semiconductor at the molecular level. The photoinduced ROS formation was monitored using a dichlorofluorescin oxidation assay, which is a conventional oxidative stress indicator. It is observed that the ROS generation under green light illumination is greater at low concentrations of RB-ZnO nanohybrids compared with free RB. Substantial photodynamic activity of the nanohybrids in bacterial and fungal cell lines validated the in vitro toxicity results. Furthermore, the cytotoxic effect of the nanohybrids in HeLa cells, which was monitored by MTT assay, is also noteworthy.


Assuntos
Antibacterianos/farmacologia , Antifúngicos/farmacologia , Antineoplásicos/farmacologia , Luz , Nanopartículas/química , Fármacos Fotossensibilizantes/farmacologia , Rosa Bengala/farmacologia , Óxido de Zinco/farmacologia , Antibacterianos/química , Antifúngicos/química , Antineoplásicos/química , Candida albicans/citologia , Candida albicans/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Escherichia coli/citologia , Escherichia coli/efeitos dos fármacos , Células HeLa , Humanos , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Processos Fotoquímicos , Fármacos Fotossensibilizantes/química , Espécies Reativas de Oxigênio/metabolismo , Rosa Bengala/química , Semicondutores , Propriedades de Superfície , Óxido de Zinco/química
19.
Indian J Med Res ; 144(6): 910-917, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28474628

RESUMO

BACKGROUND & OBJECTIVES: Increased severity of osteoarthritis (OA) and adverse side effects of its treatment led to the search for alternative therapies. It was previously reported that snake venom protein toxin Naja kaouthia cytotoxin 1 (NKCT1) and gold nanoparticle (GNP) individually have potential against excremental arthritis. In this study, we analyzed the protective activity of GNP conjugated protein toxin NKCT1 (GNP-NKCT1) against experimental OA. METHODS: Gold nanoparticle conjugation with NKCT1 (GNP-NKCT1) was done and its physiochemical properties were studied. OA was induced in male albino rats by intra-articular injection of bacterial collagenase and treatment was done with NKCT1/GNP-NKCT1/standard drug (indomethacin). Physical parameter (ankle diameter), urinary markers (hydroxyproline, glucosamine, pyridinoline, deoxypyridinoline), serum and synovial membrane pro-inflammatory markers [tumour necrosis factor-alpha (TNF-α), interleukin-1ß (IL-1ß), IL-17, vascular endothelial growth factor (VEGF)] and matrix metalloproteinase 1 (MMP1) were measured. Joint histopathology and scanning electron microscopy imaging of articular cartilage surface were also done. RESULTS: Physical parameters, urinary markers, serum and synovial membrane pro-inflammatory makers and MMP1 were increased in arthritic rats and significantly restored after GNP-NKCT1/NKCT1 treatment. Joint histopathology and scanning electron microscopy imaging of articular cartilage surface also indicated the protective effect of GNP-NKCT1 against inflammatory response and cartilage degradation in osteoarthritic rats. INTERPRETATION & CONCLUSIONS: In this study restoration of the arthritic markers and bone degradation by GNP-NKCT1 treatment indicated the anti-osteoarthritic property of GNP-NKCT1. Further studies need to be done to confirm these findings.


Assuntos
Venenos Elapídicos/administração & dosagem , Venenos Elapídicos/química , Nanopartículas Metálicas/administração & dosagem , Osteoartrite/tratamento farmacológico , Animais , Cartilagem Articular/efeitos dos fármacos , Colagenases/toxicidade , Ouro/química , Humanos , Interleucina-17/sangue , Nanopartículas Metálicas/química , Naja naja , Osteoartrite/sangue , Osteoartrite/induzido quimicamente , Osteoartrite/patologia , Ratos , Fator de Necrose Tumoral alfa/sangue , Fator A de Crescimento do Endotélio Vascular/sangue
20.
Indian J Exp Biol ; 54(9): 569-76, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-28699722

RESUMO

Pain and inflammation are intimately associated with rheumatoid arthritis, a growing bone-joint related problem of the modern society. Though several therapeutic managements are available for arthritis, their side effects not only limit their use, but also advocate the quest for natural therapies. In this study, we explored the antinociceptive, anti-inflammatory and antiarthritic activities of Bungarus fasciatus venom (BFV) in experimental animal models. Rheumatoid arthritis was induced by Freund's complete adjuvant (FCA) in male Wistar albino rats. Lyophilized BFV was diluted in 0.9% NaCl. Antiarthritic activity showed that BFV significantly reduced the paw and ankle diameters; urinary hydroxyproline, glucosamine levels and serum ACP/ALP/TNF-α/IL-1ß/IL-17/Cathepsin-K/MMP-1 levels. These parameters were significantly increased in FCA induced arthritic animals. Joint histopathology study indicated the partial restoration of joint structure. Treatment with BFV significantly reduced the mean latency time of tail flick response, acetic acid induced writhing response and formalin induced licking response in male albino mice. BFV treatment also significantly reduced carrageenan induced paw edema and xylene induced ear edema in male albino mice. The results indicated that BFV possess antinociceptive, anti-inflammatory and antiarthritic properties and further studies are warranted to find the active constituents present in BFV.


Assuntos
Analgésicos/farmacologia , Anti-Inflamatórios/farmacologia , Artrite Experimental/tratamento farmacológico , Bungarus , Venenos Elapídicos/farmacologia , Animais , Masculino , Camundongos , Ratos , Ratos Wistar
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa