Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 10 de 10
Filter
Add more filters










Publication year range
1.
Biosens Bioelectron ; 234: 115354, 2023 Aug 15.
Article in English | MEDLINE | ID: mdl-37126873

ABSTRACT

Foodborne diseases have increased in the last few years due to the increased consumption of packaged and contaminated food. Major foodborne bacteria cause diseases such as diarrhea, vomiting, and sometimes death. So, there is a need for early detection of foodborne bacteria as pre-existing detection techniques are time-taking and tedious. Aptamer has gained interest due to its high stability, specificity, and sensitivity. Here, aptamer has been developed against Salmonella Typhimurium through the Cell-Selex method, and to further find the reason for specificity and sensitivity, OmpD protein was isolated, and binding studies were done. Single molecular FRET experiment using aptamer and graphene oxide studies has also been done to understand the mechanism of FRET and subsequently used for target bacterial detection. Using this assay, Salmonella Typhimurium can be detected up to 10 CFU/mL. Further, Magnetic Graphene oxide was used to develop an assay to separate and ablate bacteria using 808 nm NIR where temperature increase was more than 60 °C within 30 s and has been shown by plating as well as a confocal live dead assay. Thus, using various techniques, bacteria can be detected and ablated using specific aptamer and Graphene oxide.


Subject(s)
Aptamers, Nucleotide , Biosensing Techniques , Foodborne Diseases , Graphite , Humans , Salmonella typhimurium , Aptamers, Nucleotide/chemistry , Biosensing Techniques/methods , Graphite/chemistry
2.
ACS Appl Mater Interfaces ; 14(1): 69-93, 2022 Jan 12.
Article in English | MEDLINE | ID: mdl-34967205

ABSTRACT

Sporadic Alzheimer's disease (sAD) is a progressive neurodegenerative disorder with dysfunctional insulin signaling and energy metabolism. Emerging evidence suggests impairments in brain insulin responsiveness, glucose utilization, and energy metabolism may be major causes of amyloid precursor protein mishandling. The support for this notion comes from the studies wherein streptozotocin (STZ) induced brain insulin resistance in rodent model resulted in sAD-like neuropathology with cognitive decline. Our previous study showed a compromised insulin signaling pathway, glucose uptake, glucose metabolism, and energy homeostasis in STZ-induced glial-neuronal coculture and in vivo model of sAD. Various components of insulin signaling pathway were examined to understand the metabolic correlation, and GSK3ß was selected for gene knockdown strategy to reverse sAD pathology based on the data. In the present study, we have synthesized carboxylated graphene oxide (GO) nanosheets functionalized with PEG and subsequently with polyethylenimine (PEI) to provide attachment sites for GSK3ß siRNA. Our results showed that siRNA mediated knockdown of the GSK3ß gene reduced expression of amyloid pathway genes (APP and BACE1), which was further confirmed by reduced amyloid beta (Aß) levels in the in vitro STZ-induced sAD model. GSK3ß knockdown also restored insulin signaling, AMPK and Mapk3 pathway by restoring the expression of corresponding candidate genes in these pathways (IR, Glut1/3, Prkaa1/2, Mapk3, BDNF) that reflected improved cellular energy homeostasis, neuronal proliferation, differentiation, maturation, and repair. Behavioral data from Morris water maze (MWM), open field (OF), novel object recognition (NOR), Y maze, and radial arm maze (RAM) tests showed that 0.5 µg nanoformulation (GOc-PP-siRNAGSK3ß) intranasally for 7 days improved spatial memory, rescued anxiety like behavior, improved visual and working memory, and rescued exploratory behavior in STZ-induced sAD rats. GSK3ß silencing resulted in decreased BACE1 expression and prevented accumulation of Aß in the cortex and hippocampus. These molecular findings with improved behavioral performances were further correlated with reduced amyloid beta (Aß) and neurofibrillary tangle (NFTs) formation in the cortex and hippocampus of GOc-PP-siRNAGSK3ß administered sAD rats. Therefore, it is conceivable from the present study that nanoparticle-mediated targeting of GSK3ß in the sAD appears to be a promising strategy to reverse sAD pathology.


Subject(s)
Alzheimer Disease/drug therapy , Drug Carriers/chemistry , Glycogen Synthase Kinase 3 beta/metabolism , Nanostructures/chemistry , RNA, Small Interfering/therapeutic use , Alzheimer Disease/etiology , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Amyloid/metabolism , Animals , Brain/drug effects , Brain/pathology , Cognitive Dysfunction/drug therapy , Cognitive Dysfunction/etiology , Cognitive Dysfunction/metabolism , Cognitive Dysfunction/pathology , Diabetes Mellitus, Experimental/chemically induced , Diabetes Mellitus, Experimental/complications , Gene Knockdown Techniques , Glycogen Synthase Kinase 3 beta/genetics , Graphite/chemistry , MAP Kinase Signaling System/drug effects , Maze Learning/drug effects , Memory/drug effects , Polyethylene Glycols/chemistry , Rats , Receptor, Insulin/metabolism , Streptozocin
3.
Org Biomol Chem ; 19(9): 2015-2022, 2021 03 11.
Article in English | MEDLINE | ID: mdl-33591294

ABSTRACT

Novel N-methylated ebselenamine antioxidants were prepared from the corresponding diselenides with iodomethane. All ebselenamines showed excellent chain-breaking and glutathione peroxidase (GPx)-like activities. They could also inhibit lipid peroxidation much more efficiently than α-tocopherol. They could also mimic the functions of the GPx-enzymes nearly two times better than ebselen in the coupled reductase assay. Also, they were found to scavenge the ROS produced at low concentration (10 µM) with low toxicity effects and could have therapeutic potential against autoxidation. It is anticipated that these compounds could potentially be used against several diseases caused by autoxidation, and thus provide protection from cell death to mammals.


Subject(s)
Azoles/pharmacology , Free Radical Scavengers/pharmacology , Organoselenium Compounds/pharmacology , Animals , Azoles/chemical synthesis , Azoles/toxicity , Cell Survival/drug effects , Free Radical Scavengers/chemical synthesis , Free Radical Scavengers/toxicity , Lipid Peroxidation/drug effects , Organoselenium Compounds/chemical synthesis , Organoselenium Compounds/toxicity , Rats
4.
Arch Pharm (Weinheim) ; 354(1): e2000181, 2021 Jan.
Article in English | MEDLINE | ID: mdl-32945576

ABSTRACT

In our continuing efforts to develop therapeutically active coumarin-based compounds, a series of new C4-C4' biscoumarin-pyrimidine conjugates (1a-l) was synthesized via SN 2 reaction of substituted 4-bromomethyl coumarin with thymine. All compounds were characterized using spectroscopic techniques, that is, attenuated total reflection infrared (ATR-IR), CHN elemental analysis, and 1 H and 13 C NMR (nuclear magnetic resonance). In addition, the structure of compound 1d (1,3-bis[(7-chloro-2-oxo-2H-chromen-4-yl)methyl]-5-methylpyrimidine-2,4(1H,3H)-dione) was established through X-ray crystallography. Compounds 1a-l were screened for in vitro anticancer activity against C6 rat glioma cells. Among the screened compounds, 1,3-bis[(6-chloro-2-oxo-2H-chromen-4-yl)methyl]-5-methylpyrimidine-2,4(1H,3H)-dione (1c) was identified as the best antiproliferative candidate, exhibiting an IC50 value of 4.85 µM. All the compounds (1a-l) were found to be nontoxic toward healthy human embryonic kidney cells (HEK293), indicating their selective nature. In addition, the most active compound (1c) displayed strong binding interactions with the drug carrier protein, human serum albumin, and exhibited good solution stability at biological pH conditions. Fluorescence, UV-visible spectrophotometry and molecular modeling methodologies were employed for studying the interaction mechanism of compound 1c with protein.


Subject(s)
Antineoplastic Agents/pharmacology , Coumarins/pharmacology , Glioma/drug therapy , Pyrimidines/pharmacology , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Cell Line, Tumor , Coumarins/chemistry , Crystallography, X-Ray , Glioma/pathology , HEK293 Cells , Humans , Inhibitory Concentration 50 , Models, Molecular , Pyrimidines/chemical synthesis , Pyrimidines/chemistry , Rats , Serum Albumin, Human/metabolism , Structure-Activity Relationship
6.
Mol Neurobiol ; 55(12): 8916-8935, 2018 Dec.
Article in English | MEDLINE | ID: mdl-29611103

ABSTRACT

Evidence from animal studies categorizes sporadic Alzheimer's disease (sAD) as a metabolic syndrome with accompanying cognitive deficits. Given that glial cells act as "silent partners" to neurons by providing trophic support and defense, the present study investigated the role of glia in sAD pathology. A streptozotocin (STZ)-induced glial-neuronal co-culture model of sAD was used to study the metabolic status of the two cell types. Real time RT-PCR and Western blotting results indicated that amyloid precursor protein (APP) and ß-secretase (BACE1) were highly expressed in co-cultured neurons than in monocultures. Increased amyloidogenesis was accompanied by decreased expression of mediators in insulin signaling pathway that included insulin receptor (IR), insulin receptor substrate 2 (IRS2), insulin-like growth factor 2 (IGF2), insulin-like growth factor 1 receptor (IGF1R), total-glycogen synthase kinase 3ß (t-GSK3ß), and phosphorylated-GSK3ßser9 (p-GSK3ßser9), suggesting that neuronal cells are more prone to metabolic variability when cultured in the presence of glial cells. Findings from the sAD model induced by intracerebroventricular (ICV) injection of STZ revealed that increased amyloid beta (Aß) load in the hippocampus was potentially responsible for the hyperphosphorylation of tau at ser396. Furthermore, impaired cognitive functions and decreased dendritic spine density and axonal thinning in CA1 region of hippocampus were associated with decreased IR and p-GSK3ßser9/t-GSK3ß expression. Taken together, the present study provides evidence that glia mediated response and insulin signaling defects drive pathological changes in sAD and represent potential targets for delaying sAD progression.


Subject(s)
Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Insulin/metabolism , Neurons/metabolism , Neurons/pathology , Signal Transduction , Alzheimer Disease/genetics , Alzheimer Disease/physiopathology , Amyloid/metabolism , Amyloid Precursor Protein Secretases/metabolism , Amyloid beta-Protein Precursor/metabolism , Animals , Brain/pathology , Cognitive Dysfunction/metabolism , Cognitive Dysfunction/pathology , Cognitive Dysfunction/physiopathology , Computer Simulation , Disease Models, Animal , Gene Expression Profiling , Gene Expression Regulation , Glucose/metabolism , Male , Neuronal Plasticity , PC12 Cells , Phosphorylation , Rats , Rats, Sprague-Dawley , Streptozocin , tau Proteins/metabolism
7.
Bioresour Technol ; 247: 633-639, 2018 Jan.
Article in English | MEDLINE | ID: mdl-28988049

ABSTRACT

The aim of the study was to covalently immobilize Smt3-D-psicose 3-epimerase onto functionalized iron oxide magnetic nanoparticles. After immobilization, Km of the immobilized enzyme increased, however, Vmax was nearly the same as that of its free form, indicating that immobilization has no detrimental effects on its catalytic output. The covalent immobilization caused a reduction in the deactivation rate constant (kd) values leading to 4-5 fold enhancement in its half-life at 50-65°C, indicating significant thermal stability of the iron-enzyme nanobioconjugate. The immobilized enzyme showed excellent storage stability by losing only 20% activity even after 60days of storage at 4°C. The immobilized enzyme retained up to 90% of its initial activity even after 10 consecutive cycles of catalyzing D-fructose epimerization reactions. Thus, after immobilization the enzyme exhibited remarkable improvements in thermal tolerance, storage stability and recycling efficiency, useful for development of industrially exploitable process for D-allulose production.


Subject(s)
Enzyme Stability , Fructose , Enzymes, Immobilized , Fruit , Hydrogen-Ion Concentration , Kinetics , Temperature
8.
Dalton Trans ; (39): 8432-42, 2009 Oct 21.
Article in English | MEDLINE | ID: mdl-19789799

ABSTRACT

Three glyco-conjugates, viz., L(1), L(2) and L(3), which differ either in their carbohydrate moiety or in their aromatic moiety or both, were synthesized and characterized and were shown to have beta-anomeric form based on (1)H NMR and optical rotation studies. Metal ion interaction studies carried out in solution by emission and absorption spectral techniques exhibited selectivity towards Cu(2+) in HEPES buffer and a two fold higher sensitivity for L(2) as compared to L(1). The composition of the complexed species has been established based on ESI MS. Dinuclear-Cu(II) complexes of all these conjugates have been synthesized and characterized based on analytical and spectral methods including FTIR, (1)H NMR, FAB MS, EPR, ORD, CD and magnetism, and the structures of and have been established based on single crystal XRD. The structures revealed subtle differences present in the orientation of the -OH groups and also their ion binding preferences both at the molecular level as well as at the lattice levels. In the dinuclear-Cu(II) complexes, while C3-O(-) of ribosyl acts as a bridging moiety in , it is the C2-O(-) of galactosyl that bridges in and the Cu(2)O(2) cores are stabilized by two intra-complex H-bond interactions formed using C4-OH in the case of and C3-OH in the case of . While the glyco-moiety is poised perpendicular to the average plane of the Cu(2)O(2) core in , this is in plane in the case of 3.


Subject(s)
Glycoconjugates/chemistry , Imines/chemistry , Metals/chemistry , Circular Dichroism , Crystallography, X-Ray , Magnetic Resonance Spectroscopy , Magnetics , Molecular Conformation , Spectrometry, Fluorescence , Spectrophotometry, Ultraviolet
9.
Glycoconj J ; 26(4): 495-510, 2009 May.
Article in English | MEDLINE | ID: mdl-18953653

ABSTRACT

Several C(1)-imino conjugates of D: -galactose, D: -lactose and D: -ribose, where the nitrogen center was substituted by the salicylidene or naphthylidene, were synthesized and characterized. Similar C(2)-imino conjugates of D: -glucose have also been synthesized. All the glyco-imino-conjugates, which are transition state analogues, exhibited 100% inhibition of the activity towards glycosidases extracted from soybean and jack bean meal. Among these, a galactosyl-napthyl-imine-conjugate (1c) showed 50% inhibition of the activity of pure alpha-mannosidase from jack bean at 22 +/- 2.5 microM, and a ribosyl-naphthyl-imine-conjugate (3c) showed at 31 +/- 5.5 microM and hence these conjugates are potent inhibitors of glycosidases. The kinetic studies suggested non-competitive inhibition by these conjugates. The studies are also suggestive of the involvement of aromatic, imine and carbohydrate moieties of the glyco-imino-conjugates in the effective inhibition. The binding of glyco-imino-conjugate has been established by extensive studies carried out using fluorescence emission and isothermal titration calorimetry. The conformational changes resulted in the enzyme upon interaction of these derivatives has been established by studying the fluorescence quench of the enzyme by KI as well as from the secondary structural changes noticed in CD spectra. All these studies revealed the difference in the binding strengths of the naphthylidene vs. salicylidene as well as galactosyl vs. lactosyl moieties present in these conjugates. The differential inhibition of these glyco-conjugates has been addressed by quantifying the specific interactions present between the glyco-conjugates and the enzyme by using rigid docking studies.


Subject(s)
Fabaceae/enzymology , Glycine max/enzymology , Glycoconjugates/chemistry , Glycoconjugates/pharmacology , Glycoside Hydrolases/antagonists & inhibitors , Glycoside Hydrolases/isolation & purification , Models, Molecular , Amino Acids/metabolism , Calorimetry , Carbohydrate Conformation , Catalytic Domain , Circular Dichroism , Glycoside Hydrolases/chemistry , Inhibitory Concentration 50 , Kinetics , Protein Structure, Secondary , Spectrometry, Fluorescence , Titrimetry
10.
J Org Chem ; 72(9): 3430-42, 2007 Apr 27.
Article in English | MEDLINE | ID: mdl-17394358

ABSTRACT

A galactosyl-naphthyl-imine-based derivative, 1-(beta-D-galactopyranosyl-1'-deoxy-1'-iminomethyl)-2-hydroxynaphthalene (GNI), and a galactosyl-naphthyl-amine-based derivative, 1-(galactopyranosyl-1'-deoxy-1'-aminomethyl)-2-hydroxynaphthalene (GNA), possessing an ONO binding core were studied for their recognition of naturally occurring amino acids using fluorescence and absorption spectroscopy, and the corresponding association constants were derived for the complexes formed. The complexes formed between GNI/GNA and amino acids were supported by electrospray ionization mass spectrometry (ESI/MS). The structures of the complexes were optimized by computational studies using density functional theory, and stabilization energies were computed for the complexes to substantiate the interactions present between GNI/GNA and amino acid. The interactions were found to be primarily hydrogen bonding in nature. These interactions are reminiscent of those present in the lectin-carbohydrate and glycosidase substrate. Thus, the carbohydrate moiety present in GNI shows high specificity toward the -COOH group of the amino acid, which may be relevant to such interactions present between the carbohydrates and the polypeptides.


Subject(s)
Amino Acids/metabolism , Absorption , Amino Acids/chemistry , Binding Sites , Carbohydrate Metabolism , Carbohydrates/chemistry , Fluorescence , Galactosides/chemistry , Galactosides/metabolism , Lectins/chemistry , Lectins/metabolism , Models, Chemical , Models, Molecular , Naphthalenes/chemistry , Naphthalenes/metabolism , Normal Distribution , Spectrometry, Fluorescence , Spectrometry, Mass, Electrospray Ionization , Time Factors , Titrimetry
SELECTION OF CITATIONS
SEARCH DETAIL
...