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1.
PLoS Pathog ; 19(9): e1011686, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37773952

RESUMO

One of the mechanisms shaping the pathophysiology during the infection of enteric pathogen Salmonella Typhimurium is host PTM machinery utilization by the pathogen encoded effectors. Salmonella Typhimurium (S. Tm) during infection in host cells thrives in a vacuolated compartment, Salmonella containing vacuole (SCV), which sequentially acquires host endosomal and lysosomal markers. Long tubular structures, called as Salmonella induced filaments (SIFs), are further generated by S. Tm, which are known to be required for SCV's nutrient acquisition, membrane maintenance and stability. A tightly coordinated interaction involving prominent effector SifA and various host adapters PLEKHM1, PLEKHM2 and Rab GTPases govern SCV integrity and SIF formation. Here, we report for the first time that the functional regulation of SifA is modulated by PTM SUMOylation at its 11th lysine. S. Tm expressing SUMOylation deficient lysine 11 mutants of SifA (SifAK11R) is defective in intracellular proliferation due to compromised SIF formation and enhanced lysosomal acidification. Furthermore, murine competitive index experiments reveal defective in vivo proliferation and weakened virulence of SifAK11R mutant. Concisely, our data reveal that SifAK11R mutant nearly behaves like a SifA knockout strain which impacts Rab9-MPR mediated lysosomal acidification pathway, the outcome of which culminates in reduced bacterial load in in vitro and in vivo infection model systems. Our results bring forth a novel pathogen-host crosstalk mechanism where the SUMOylation of effector SifA regulated S. Tm intracellular survival.

2.
J Biol Chem ; 299(4): 103017, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36791912

RESUMO

Tight coordination of growth regulatory signaling is required for intestinal epithelial homeostasis. Protein kinase C α (PKCα) and transforming growth factor ß (TGFß) are negative regulators of proliferation with tumor suppressor properties in the intestine. Here, we identify novel crosstalk between PKCα and TGFß signaling. RNA-Seq analysis of nontransformed intestinal crypt-like cells and colorectal cancer cells identified TGFß receptor 1 (TGFßR1) as a target of PKCα signaling. RT-PCR and immunoblot analysis confirmed that PKCα positively regulates TGFßR1 mRNA and protein expression in these cells. Effects on TGFßR1 were dependent on Ras-extracellular signal-regulated kinase 1/2 (ERK) signaling. Nascent RNA and promoter-reporter analysis indicated that PKCα induces TGFßR1 transcription, and Runx2 was identified as an essential mediator of the effect. PKCα promoted ERK-mediated activating phosphorylation of Runx2, which preceded transcriptional activation of the TGFßR1 gene and induction of Runx2 expression. Thus, we have identified a novel PKCα→ERK→Runx2→TGFßR1 signaling axis. In further support of a link between PKCα and TGFß signaling, PKCα knockdown reduced the ability of TGFß to induce SMAD2 phosphorylation and cell cycle arrest, and inhibition of TGFßR1 decreased PKCα-induced upregulation of p21Cip1 and p27Kip1 in intestinal cells. The physiological relevance of these findings is also supported by The Cancer Genome Atlas data showing correlation between PKCα, Runx2, and TGFßR1 mRNA expression in human colorectal cancer. PKCα also regulated TGFßR1 in endometrial cancer cells, and PKCα, Runx2, and TGFßR1 expression correlates in uterine tumors, indicating that crosstalk between PKCα and TGFß signaling may be a common mechanism in diverse epithelial tissues.


Assuntos
Neoplasias Colorretais , Subunidade alfa 1 de Fator de Ligação ao Core , Proteína Quinase C-alfa , Receptor do Fator de Crescimento Transformador beta Tipo I , Humanos , Neoplasias Colorretais/genética , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Células Epiteliais/metabolismo , Intestinos , Proteína Quinase C-alfa/genética , Proteína Quinase C-alfa/metabolismo , RNA Mensageiro/genética , Fator de Crescimento Transformador beta/metabolismo , Receptor do Fator de Crescimento Transformador beta Tipo I/genética , Receptor do Fator de Crescimento Transformador beta Tipo I/metabolismo
3.
Br J Haematol ; 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38978231

RESUMO

Sickle cell disease (SCD) is one of the most common genetic disorders in the world predominantly affecting economically disadvantaged populations. There is a notable discrepancy between the growing adult SCD population and available diagnostic and therapeutic interventions for SCD. Sickle cell hepatopathy (SCH) is an all-inclusive term to describe the acute and chronic liver manifestations of SCD. The pathophysiology of SCH follows no defined pattern or sequence that poses challenges to clinicians and researchers alike. Evidence is lacking for this underreported disease at various levels from diagnostic to therapeutic options. This paper reviews the basic pathophysiology, clinical features, biochemical and radiological findings of various SCH manifestations and outlines the management of each condition. Old and new therapy options in SCD including hydroxyurea, red blood cell exchange transfusion, ursodeoxycholic acid, voxelotor, l-glutamine and crizanlizumab have been reviewed to investigate the role of these options in treating SCH. The role of liver transplant, haematopoietic stem cell transplant and gene therapy in SCH patients have been reviewed.

4.
Bioconjug Chem ; 35(9): 1283-1299, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39207940

RESUMO

Lipid nanoparticles have been recognized as a powerful weapon for delivering various imaging and therapeutic agents to the localized solid tumors, especially brain tumors individually or in combination. Promisingly, lipid-based nanosystems have been considered as safe delivery systems which are even approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA). One recent spotlight of lipid nanoparticles as COVID-19 mRNA vaccines where lipid nanoparticles play an important role in effectively protecting and delivering mRNA to the desired cells. As of now, successive progress in lipid-based nanocarriers, viz., nanoliposomes, solid lipid nanoparticles, ionizable lipid nanostructures, etc., with better biochemical and biophysical stabilities, has been noticed and reported. Moreover, lipid nanostructures have been considered as versatile therapeutics platforms for a variety of diseases due to their biocompatibility, ability to protect and deliver therapeutics to the localized site, and better reproducibility and reliability. However, lipid nanoparticles still face morphological and biochemical changes upon their in vivo administration. These changes alter the specific biological and pathological response of lipid nanoparticles during their personalized brain tumor theranostics. Second, lipid nanomedicine still faces major challenges of zero premature leakage of loaded cargo, long-term colloidal stability, and off targeting. Herein, various lipid-based nanomedicines for brain tumor imaging and therapeutics "theranostics" have been reviewed and summarized considering major aspects of preclinical and clinical studies. On the other hand, engineering and biological challenges of lipid theranostics systems with relevant advantages and guidelines for clinical practice for different brain tumors have also been discussed. This review provides in-depth knowledge of lipid nanoparticle-based theranostics agents for brain tumor imaging and therapeutics.


Assuntos
Neoplasias Encefálicas , Lipídeos , Nanopartículas , Nanomedicina Teranóstica , Humanos , Neoplasias Encefálicas/terapia , Neoplasias Encefálicas/diagnóstico por imagem , Nanomedicina Teranóstica/métodos , Nanopartículas/química , Lipídeos/química , Animais , COVID-19 , Lipossomos/química , Sistemas de Liberação de Medicamentos/métodos
5.
Bull World Health Organ ; 102(7): 476-485C, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38933479

RESUMO

Objective: To assess the availability of information on indicators of the World Health Organization and United Nations Children's Fund primary health-care measurement framework in Bangladesh, India, Nepal, Pakistan and Sri Lanka and to outline the opportunities for and challenges to using the framework in these countries. Methods: We reviewed global and national data repositories for quantitative indicators of the framework and conducted a desk review of country documents for qualitative indicators in February-April 2023. We assessed data sources and cross-sectional survey tools to suggest possible sources of information on framework indicators that were not currently reported in the countries. We also identified specific indicators outside the framework on which information is collected in the countries and which could be used to measure primary health-care performance. Findings: Data on 54% (32/59) of the quantitative indicators were partially or completely available for the countries, ranging from 41% (24/59) in Pakistan to 64% (38/59) in Nepal. Information on 41% (66/163) of the qualitative subindicators could be acquired through desk reviews of country-specific documents. Information on input indicators was more readily available than on process and output indicators. The feasibility of acquiring information on the unreported indicators was moderate to high through adaptation of data collection instruments. Conclusion: The primary health-care measurement framework provides a platform to readily assess and track the performance of primary health care. Countries should improve the completeness, quality and use of existing data for strengthening of primary health care.


Assuntos
Atenção Primária à Saúde , Nações Unidas , Organização Mundial da Saúde , Humanos , Atenção Primária à Saúde/organização & administração , Nepal , Bangladesh , Paquistão , Índia , Estudos Transversais , Sri Lanka , Indicadores de Qualidade em Assistência à Saúde
6.
Chemistry ; 30(45): e202401239, 2024 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-38818941

RESUMO

Herein, we describe water-soluble heteroaryl azopyridinium ionic photoswitches (HAPIPs). We aim to combine variations in five-membered heterocycles, their substitutions, N-alkyl groups at pyridinium nitrogen, the position of pyridinium center relative to azo group, counterions, and solvents, in achieving better photoswitching. Through these studies, we successfully tuned the half-life of Z isomers of the resultant HAPIPs between seconds to days in water. Extensive spectroscopic studies and density functional theory (DFT) computations unravelled the factors responsible for thermal relaxation behavior. Considering the versatility of these photoswitches, the tunability of half-lives and photoswitching in aqueous medium allows the scope of applications in several fields.

7.
Langmuir ; 40(25): 12911-12924, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38691550

RESUMO

Multifunctional carbon-based materials exhibit a large number of unprecedented active sites via an electron transfer process and act as a desired platform for exploring high-performance electroactive material. Herein, we exemplify the holistic design of a heterometallic nanostructured material (MWCNTs@KR-6/Mn/Sn/Pb) formed by the integration of metals (Mn2+, Sn2+, and Pb2+) and a dipodal ligand (KR-6) at the surface of multiwalled carbon nanotubes (MWCNTs). First, MWCNTs@KR-6 was readily synthesized via a noncovalent approach, which was further sequentially doped by Mn2+, Sn2+, and Pb2+ to give MWCNTs@KR-6/Mn/Sn/Pb. The designed material showed excellent electrochemical activity for the discrimination of insecticides belonging to structurally different classes. In contrast to that of the individual building components, both the stability and electrochemical activity of heterometallic nanostructured material were remarkably enhanced, resulting in a magnificent electrochemical performance of the developed material. Hence, the current work reports a comprehensive synthetic approach for MWCNTs@KR-6/Mn/Sn/Pb synthesis by synergizing unique properties of the heterometallic complex with MWCNTs. This work also offers a new insight into the design of multifunctional carbon-based materials for discrimination of different analytes on the basis of their redox potential.

8.
Langmuir ; 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38319126

RESUMO

In recent years, the issue of pharmaceutical contaminants in water bodies has emerged as a significant environmental concern owing to the potential negative impacts on both aquatic ecosystems and human health. Consequently, the development of efficient and eco-friendly methods for their determination and removal is of paramount importance. In this context, the development of a surfactant ensemble sensor has been explored for hard-to-sense amphiphilic drug, i.e., amitriptyline. Herein, a pyrene-based amphiphile chemoreceptor was synthesized and characterized through various spectroscopic techniques such as 1H, 13C NMR, single-crystal XRD, FTIR, and ES-mass spectrometry. Then, dodecanoic acid (DA) and a pyrene-based receptor in a THF/water solvent system were used to generate reverse micelle-based self-aggregates of SUPRAS (SUPRAmolecular Solvent). The structural aspects, such as morphology and size, along with the stability of the SUPRAS aggregates were unfolded through spectroscopic and microscopic insights. The present investigation describes a synergistic approach that combines the unique properties of premicellar concentration of supramolecular solvent with the promising potential of pyrene-based receptor for enhanced amitriptyline extraction with simultaneous determination from water (LOD = 12 nM). To evaluate the effectiveness of the developed aggregates in real-world scenarios, experiments were conducted to determine the sensing efficiency among various pharmaceutical pollutants commonly found in water sources. The results reveal that the synergistic nanoensemble exhibits remarkable sensing ability, toward the amitriptyline (AMT) drug outperforming conventional methods.

9.
J Fluoresc ; 34(2): 935-943, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37432582

RESUMO

A naked eye and fluorescence turn-on 1,8-naphtahlimide based chemosensor,1, possessing Schiff base linkage was utilized for the rapid detection of highly toxic triphosgene. The proposed sensor selectively detected triphosgene over various other competitive analytes including phosgene with the detection limit of 6.15 and 1.15 µM measured using UV-vis and fluorescence spectrophotometric techniques, respectively. Colorimetric changes observed in solution phase were processed by image analysis using smartphone leading to on-site and inexpensive determination of triphosgene. Further, solid phase sensing of triphosgene was carried out by 1 loaded PEG membranes and silica gel.


Assuntos
Fosgênio , Fosgênio/análogos & derivados , Fosgênio/análise , Corantes Fluorescentes , Smartphone , Espectrometria de Fluorescência/métodos
10.
Clin Nephrol ; 101(3): 152-154, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38214175

RESUMO

Opportunistic infections are common in transplant recipients, but gastrointestinal bleed is rarely reported to be due to opportunistic fungal infections, and hence could present as a diagnostic challenge. We report a case of disseminated histoplasmosis in a kidney transplant recipient whose initial presentation was acute lower gastrointestinal bleeding with no other symptoms. The colonoscopy showed scattered punchout circular colonic ulcers with biopsy revealing budding yeasts consistent with a diagnosis of histoplasmosis. The patient was successfully treated with a prolonged course of intravenous amphotericin B followed by oral itraconazole.


Assuntos
Histoplasmose , Transplante de Rim , Humanos , Antifúngicos/uso terapêutico , Transplante de Rim/efeitos adversos , Transplantados , Itraconazol , Histoplasmose/diagnóstico , Histoplasmose/tratamento farmacológico , Histoplasmose/patologia , Hemorragia Gastrointestinal/diagnóstico , Hemorragia Gastrointestinal/etiologia , Hemorragia Gastrointestinal/tratamento farmacológico
11.
Breed Sci ; 74(1): 37-46, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-39246437

RESUMO

We review the undertaking of a field trial of low asparagine wheat lines in which the asparagine synthetase gene, TaASN2, has been knocked out using CRISPR/Cas9. The field trial was undertaken in 2021-2022 and represented the first field release of genome edited wheat in Europe. The year of the field trial and the period since have seen rapid changes in the regulations covering both the field release and commercialisation of genome edited crops in the UK. These historic developments are reviewed in detail. Free asparagine is the precursor for acrylamide formation during high-temperature cooking and processing of grains, tubers, storage roots, beans and other crop products. Consequently, work on reducing the free asparagine concentration of wheat and other cereal grains, as well as the tubers, beans and storage roots of other crops, is driven by the need for food businesses to comply with current and potential future regulations on acrylamide content of foods. The topic illustrates how strategic and applied crop research is driven by regulations and also needs a supportive regulatory environment in which to thrive.

12.
Molecules ; 29(5)2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38474626

RESUMO

The current study describes a novel and eco-conscious method to synthesize 1,4-dihydropyridine derivatives utilizing an aqueous micellar solution containing aluminum dodecyl sulfate, Al(DS)3, using readily available starting material. The final products were synthesized with excellent yields within remarkably quick reaction durations, promoting remarkable atom economy and minimizing environmental impacts. The present protocol has several advantages over other methodologies in terms of high yield (up to 97%) with excellent purity. Further, the synthesized 1,4-DHPs exhibit favorable to excellent resistance against examined bacterial and fungal species. Intriguingly, polar groups on the phenyl ring (5b, 5c, 5i and 5j) make the 1,4-DHPs equally potent against the microbes as compared to the standard drugs.


Assuntos
Di-Hidropiridinas , Compostos Heterocíclicos , Micro-Ondas , Alumínio
13.
Artigo em Inglês | MEDLINE | ID: mdl-38635134

RESUMO

The current study was designed to describe usual clinical care for youth with primary anxiety problems in community mental health centers. The observer-rated Therapy Process Observational Coding System for Child Psychotherapy - Revised Strategies scale (TPOCS-RS), designed to assess therapeutic techniques from five theory-based domains, was used to code sessions (N = 403) from the usual clinical care group of two randomized effectiveness trials: (a) Youth Anxiety Study (YAS) with 21 youth (M age = 10.44 years, SD = 1.91; 49.2% Latinx; 46.6%, 53.4% male) and 16 clinicians (77.5% female; 43.8% White), and (b) Child STEPS Multisite Trial with 17 youth (M age = 10.00 years, SD = 1.87; 58.8% male; 41.2% White) and 13 clinicians (M age = 40.00 years; SD = 9.18; 76.9% female; 61.5% White). The average number of TPOCS-RS items observed per treatment session was more than 10, and multiple techniques were used together in each session. All TPOCS-RS items were observed at least once throughout a clinical case, and most items reoccurred (i.e., observed in two or more sessions). The dosage of TPOCS-RS in all items was below 5 on a 7-point scale. In conclusion, clinicians in both usual care samples used a wide range of techniques from several theory-based domains at a low to medium dose. However, the type and dosage of the techniques used did vary across the two samples.

14.
J Biol Chem ; 298(7): 102121, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35697074

RESUMO

We have previously shown that the serine/threonine kinase PKCα triggers MAPK/ERK kinase (MEK)-dependent G1→S cell cycle arrest in intestinal epithelial cells, characterized by downregulation of cyclin D1 and inhibitor of DNA-binding protein 1 (Id1) and upregulation of the cyclin-dependent kinase inhibitor p21Cip1. Here, we use pharmacological inhibitors, genetic approaches, siRNA-mediated knockdown, and immunoprecipitation to further characterize antiproliferative ERK signaling in intestinal cells. We show that PKCα signaling intersects the Ras-Raf-MEK-ERK kinase cascade at the level of Ras small GTPases and that antiproliferative effects of PKCα require active Ras, Raf, MEK, and ERK, core ERK pathway components that are also essential for pro-proliferative ERK signaling induced by epidermal growth factor (EGF). However, PKCα-induced antiproliferative signaling differs from EGF signaling in that it is independent of the Ras guanine nucleotide exchange factors (Ras-GEFs), SOS1/2, and involves prolonged rather than transient ERK activation. PKCα forms complexes with A-Raf, B-Raf, and C-Raf that dissociate upon pathway activation, and all three Raf isoforms can mediate PKCα-induced antiproliferative effects. At least two PKCα-ERK pathways that collaborate to promote growth arrest were identified: one pathway requiring the Ras-GEF, RasGRP3, and H-Ras, leads to p21Cip1 upregulation, while additional pathway(s) mediate PKCα-induced cyclin D1 and Id1 downregulation. PKCα also induces ERK-dependent SOS1 phosphorylation, indicating possible negative crosstalk between antiproliferative and growth-promoting ERK signaling. Importantly, the spatiotemporal activation of PKCα and ERK in the intestinal epithelium in vivo supports the physiological relevance of these pathways and highlights the importance of antiproliferative ERK signaling to tissue homeostasis in the intestine.


Assuntos
Ciclina D1 , Proteína Quinase C-alfa , Ciclina D1/genética , Ciclina D1/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Fator de Crescimento Epidérmico/farmacologia , Células Epiteliais/metabolismo , Mucosa Intestinal/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Proteína Quinase C-alfa/genética , Proteína Quinase C-alfa/metabolismo , Proteínas Serina-Treonina Quinases , Proteínas Proto-Oncogênicas c-raf/genética , Proteínas Proto-Oncogênicas c-raf/metabolismo , Proteínas ras/genética , Proteínas ras/metabolismo
15.
J Am Chem Soc ; 145(19): 10584-10594, 2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37133353

RESUMO

We report a new class of arylazopyrazolium-based ionic photoswitches (AAPIPs). These AAPIPs with different counter ions have been accessed through a modular synthetic approach in high yields. More importantly, the AAPIPs exhibit excellent reversible photoswitching and exceptional thermal stability in water. The effects of solvents, counter ions, substitutions, concentration, pH, and glutathione (GSH) have been evaluated using spectroscopic investigations. The results revealed that the bistability of studied AAPIPs is robust and near quantitative. The thermal half-life of Z isomers is extremely high in water (up to years), and it can be lowered electronically by the electron-withdrawing groups or highly basic pH.

16.
Anal Chem ; 95(39): 14533-14540, 2023 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-37726218

RESUMO

Modern agricultural practice relies heavily on pesticides and herbicides to increase crop productivity, and consequently, their residues have a negative impact on the environment and public health. Thus, keeping these issues in account, herein we developed an azodye-based chromogenic sensor array for the detection and discrimination of pesticides and herbicides in food and soil samples, utilizing machine learning approaches such as hierarchical clustering analysis, principal component analysis, linear discriminant analysis (LDA), and partial least square regression (PLSR). The azodye-based sensor array was developed in combination with various metal ions owing to their different photophysical properties, which led to distinct patterns toward various pesticides and herbicides. The obtained distinct patterns were recognized and processed through automated multivariate analysis, which enables the selective and sensitive identification and discrimination of various target analytes. Further, the qualitative and quantitative determination of target analytes were performed using LDA and PLSR; the results obtained show a linear correlation with varied concentrations of target analytes with R2 values from 0.89 to 0.96, the limit of detection from 5.3 to 11.8 ppm with a linear working range from 1 to 30 µM toward analytes under investigation. Further, the developed sensor array was successfully utilized for the discrimination of a binary mixture of pesticide (chlorpyrifos) and herbicide (glyphosate).


Assuntos
Clorpirifos , Herbicidas , Praguicidas , Praguicidas/análise , Análise Multivariada , Análise por Conglomerados
17.
Chemistry ; 29(30): e202300017, 2023 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-36880483

RESUMO

The development of a universal approach for precisely tuning the electrochemical characteristics of conducting carbon nanotubes for tracking harmful agents in the human body with high selectivity and sensitivity remains a challenge. Herein, we describe a simplistic, versatile, and general approach to the construction of functionalized electrochemical material. The design of electrochemical material consists of (i) modification of multiwalled carbon nanotubes (MWCNT) with dipodal naphthyl-based dipodal urea (KR-1) through non-covalent functionalization (KR-1@MWCNT) which enhances the dispersibility of MWCNT and hence conductivity, (ii) complexation of KR-1@MWCNT with Hg2+ accelerate the electron transfer in the material which amplify the detection response of functionalized material (i. e., Hg/KR-1@MWCNT) towards various thymidine analogues. Further, the application of functionalized electrochemical material (Hg/KR-1@MWCNT) achieves real-time electrochemical monitoring of harmful antiviral drug 5-iodo-2'-iododeoxyuridine (IUdR) levels in human serum for the first time.


Assuntos
Nanotubos de Carbono , Humanos , Nanotubos de Carbono/química , Antivirais , Técnicas Eletroquímicas , Idoxuridina
18.
Chemistry ; 29(60): e202301906, 2023 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-37477625

RESUMO

We report the design and synthesis of eight photoswitchable phenylazopyridine- and phenylazopyrazole-based molecular systems as chelation-type light-controllable ligands. Besides the studies on fundamental photoisomerization behaviour, the ligands were also screened for light-tuneable properties such as photochromism, phase transition, and solubility, especially in the aqueous medium. This investigation demonstrates how the modulation of aqueous solubility can be achieved through photoisomerization and can further be utilized towards controlling the amount of catalytically active Cu(I) species in the aqueous conditions. Through this approach, light control over the catalytic activity was achieved for Cu-catalyzed azide-alkyne cycloaddition (CuAAC) reactions, along with a partial recovery of the catalytically active species.

19.
Anal Biochem ; 675: 115216, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37353067

RESUMO

A novel fluorenone appended Schiff base (L) has been synthesized and utilized for studying the binding interactions with Calf Thymus DNA (ct-DNA). The mechanism of binding with ct-DNA was explored by employing various spectroscopic techniques viz. UV-Vis absorption spectroscopy, fluorescence emission spectroscopy, gel-electrophoresis, circular dichroism (CD), melting studies, viscosity arrays and molecular modeling methodology. The interpretation of UV-vis absorbance spectra pointed to binding of L within minor groove of ct-DNA with the binding constant of Kb = 0.15 × 104 M-1. Dye-displacement studies with Rhodamine-B (RhB) and Ethylene Bromide (EB) in fluorescence spectroscopy verified the groove binding mode of interaction between L and ct-DNA. Melting studies, circular dichroism, and viscosity studies further elucidated the binding modes of L with ct-DNA. Thermodynamic variable measurements taken at various temperatures such as ΔG°, ΔH°, and ΔS° revealed that hydrophobic forces played a significant role in the binding process. The meticulous computational interaction demonstrated by molecular docking confirmed the minor groove binding of L with ct-DNA.


Assuntos
DNA , Bases de Schiff , Simulação de Acoplamento Molecular , Espectrofotometria Ultravioleta , DNA/química , Dicroísmo Circular , Espectrometria de Fluorescência , Termodinâmica , Viscosidade
20.
Chemphyschem ; 24(22): e202200809, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37515550

RESUMO

Core-shell nanostructures of silicon oxide@noble metal have drawn a lot of interest due to their distinctive characteristics and minimal toxicity with remarkable biocompatibility. Due to the unique property of localized surface plasmon resonance (LSPR), plasmonic nanoparticles are being used as surface-enhanced Raman scattering (SERS) based detection of pollutants and photothermal (PT) agents in cancer therapy. Herein, we demonstrate the synthesis of multifunctional silica core - Au nanostars shell (SiO2 @Au NSs) nanostructures using surfactant free aqueous phase method. The SERS performance of the as-synthesized anisotropic core-shell NSs was examined using Rhodamine B (RhB) dye as a Raman probe and resulted in strong enhancement factor of 1.37×106 . Furthermore, SiO2 @Au NSs were also employed for PT killing of breast cancer cells and they exhibited a concentration-dependent increase in the photothermal effect. The SiO2 @Au NSs show remarkable photothermal conversion efficiency of up to 72 % which is unprecedented. As an outcome, our synthesized NIR active SiO2 @Au NSs are of pivotal importance to have their dual applications in SERS enhancement and PT effect.

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