95 results on '"Bora, U."'
Search Results
52. Greener Biogenic Approach for the Synthesis of Palladium Nanoparticles Using Papaya Peel: An Eco-Friendly Catalyst for C-C Coupling Reaction.
- Author
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Dewan A, Sarmah M, Thakur AJ, Bharali P, and Bora U
- Abstract
The development of a green and sustainable synthetic methodology still remains a challenge across the globe. Encouraging the prevailing challenge, herein, we have synthesized Pd nanoparticles (Pd NPs) in a green and environmentally viable route, using the extract of waste papaya peel without the assistance of any reducing agents, high-temperature calcination, and reduction procedures. The biomolecules present in the waste papaya peel extract reduced Pd(II) to nanosize Pd(0) in a one-pot green and sustainable process. As a catalyst, the new Pd NPs offer a simple and efficient methodology in direct Suzuki-Miyaura and Sonogashira coupling with excellent yields under mild reaction conditions., Competing Interests: The authors declare no competing financial interest.
- Published
- 2018
- Full Text
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53. Phospholipases play multiple cellular roles including growth, stress tolerance, sexual development, and virulence in fungi.
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Barman A, Gohain D, Bora U, and Tamuli R
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- Binding Sites physiology, Calcium Signaling physiology, Catalytic Domain physiology, Fungi genetics, Fungi metabolism, Humans, Stress, Physiological physiology, Fungi growth & development, Fungi pathogenicity, Lysophospholipase metabolism, Phospholipase D metabolism, Phospholipases A metabolism, Type C Phospholipases metabolism
- Abstract
Phospholipases are ubiquitous enzymes that hydrolyze phospholipids. Based on the cleavage site of the ester linkage in the substrate phospholipids, phospholipases are classified into four major types, phospholipase A (PLA), phospholipase B (PLB), phospholipase C (PLC), and phospholipase D (PLD), which are further classified into various subtypes. Phospholipases hydrolyze phospholipids into various signaling products including phosphatidic acid (PA), diacylglycerol (DAG), free fatty acids (FFAs), and lyso-phospholipids (LPLs). These signaling products regulate numerous processes such as cytoskeletal dynamics, growth, homeostasis, membrane remodeling, nutrient acquisition, secretion, signal transduction, stress tolerance, sexual development, and virulence in various organisms including fungi. Due to these key cellular roles, phospholipases are also promising targets in diagnostic and therapeutic applications. In this review, we discuss current knowledge about the cellular roles of different classes of phospholipases in fungi., (Copyright © 2018 Elsevier GmbH. All rights reserved.)
- Published
- 2018
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54. The mitochondrial genome of Muga silkworm (Antheraea assamensis) and its comparative analysis with other lepidopteran insects.
- Author
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Singh D, Kabiraj D, Sharma P, Chetia H, Mosahari PV, Neog K, and Bora U
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- Animals, Base Sequence, Phylogeny, RNA, Ribosomal genetics, RNA, Transfer genetics, Sequence Homology, Nucleic Acid, Genome, Mitochondrial, Lepidoptera genetics, Moths genetics
- Abstract
Muga (Antheraea assamensis) is an economically important silkmoth endemic to the states of Assam and Meghalaya in India and is the producer of the strongest known commercial silk. However, there is a scarcity of genomic and proteomic data for understanding the organism at a molecular level. Our present study is on decoding the complete mitochondrial genome (mitogenome) of A. assamensis using next generation sequencing technology and comparing it with other available lepidopteran mitogenomes. Mitogenome of A. assamensis is an AT rich circular molecule of 15,272 bp (A+T content ~80.2%). It contains 37 genes comprising of 13 protein coding genes (PCGs), 22 tRNA and 2 rRNA genes along with a 328 bp long control region. Its typical tRNAMet-tRNAIle-tRNAGln arrangement differed from ancestral insects (tRNAIle-tRNAGln-tRNAMet). Two PCGs cox1 and cox2 were found to have CGA and GTG as start codons, respectively as reported in some lepidopterans. Interestingly, nad4l gene showed higher transversion mutations at intra-species than inter-species level. All PCGs evolved under strong purifying selection with highest evolutionary rates observed for atp8 gene while lowest for cox1 gene. We observed the typical clover-leaf shaped secondary structures of tRNAs with a few exceptions in case of tRNASer1 and tRNATyr where stable DHU and TΨC loop were absent. A significant number of mismatches (35) were found to spread over 19 tRNA structures. The control region of mitogenome contained a six bp (CTTAGA/G) deletion atypical of other Antheraea species and lacked tandem repeats. Phylogenetic position of A. assamensis was consistent with the traditional taxonomic classification of Saturniidae. The complete annotated mitogenome is available in GenBank (Accession No. KU379695). To the best of our knowledge, this is the first report on complete mitogenome of A. assamensis.
- Published
- 2017
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55. Electrospun silk-polyaniline conduits for functional nerve regeneration in rat sciatic nerve injury model.
- Author
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Das S, Sharma M, Saharia D, Sarma KK, Muir EM, and Bora U
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- Animals, Biocompatible Materials chemistry, Biocompatible Materials toxicity, Cell Line, Disease Models, Animal, Female, Fibroins, Materials Testing, Nanocomposites chemistry, Nanocomposites toxicity, Peripheral Nerve Injuries pathology, Peripheral Nerve Injuries physiopathology, Rats, Rats, Sprague-Dawley, Schwann Cells cytology, Schwann Cells drug effects, Sciatic Nerve pathology, Sciatic Nerve physiopathology, Sciatic Neuropathy pathology, Sciatic Neuropathy physiopathology, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, Tissue Scaffolds chemistry, Aniline Compounds chemistry, Aniline Compounds toxicity, Nerve Regeneration drug effects, Nerve Regeneration physiology, Peripheral Nerve Injuries therapy, Sciatic Nerve injuries, Sciatic Neuropathy therapy, Silk
- Abstract
The present study describes the fabrication of polyaniline-silk fibroin (PASF) nanocomposite-based nerve conduits and their subsequent implantation in a rat sciatic nerve injury model for peripheral nerve regeneration. This is the first in vivo study of polyaniline-based nerve conduits describing the safety and efficacy of the conduits in treating peripheral nerve injuries. The nanocomposite was synthesized by electrospinning a mixture of silk fibroin protein and polyaniline wherein the silk nanofibers were observed to be uniformly coated with polyaniline nanoparticles. Tubular shaped nerve conduits were subsequently formed by multiple rolling of the electrospun sheet over a stainless steel mandrel. The conduits were characterized in vitro for their physico-chemical properties as well as their compatibility with rat Schwann cells. Upon implantation in a 10 mm sciatic nerve injury model, the conduits were evaluated for their neuro-regenerative potential through extensive electrophysiological studies and monitoring of gait pattern over a course of 12 months. Gross examination, histological and ultra-structure analyses of the conduits and the regenerated nerve were also performed to evaluate morphological regeneration of transected nerve. PASF nanocomposite conduits seeded with Schwann cell (cell seeded PASF) exhibited excellent nerve conduction velocity (NCV) (50 m s
-1 ), compound muscle action potential (CMAP) (12.8 mV), motor unit potential (MUP) (124 μV), growth of healthy tissue along the nerve gap and thick myelination of axons 12 months after implantation indicating enhanced neuro-regeneration. The excellent functional recovery achieved by animals implanted with cell seeded PASF conduits (86.2% NCV; 80.00% CMAP; 76.07% MUP) are superior to outcomes achieved previously with similar electrically conductive conduits. We believe that the present study would encourage further research in developing electrically active neural implants using synthetic conducting polymers and the in vivo applications of the same.- Published
- 2017
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56. De novo transcriptome of the muga silkworm, Antheraea assamensis (Helfer).
- Author
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Chetia H, Kabiraj D, Singh D, Mosahari PV, Das S, Sharma P, Neog K, Sharma S, Jayaprakash P, and Bora U
- Subjects
- Amino Acid Sequence, Animals, Gene Library, Gene Ontology, Genes, Insect genetics, High-Throughput Nucleotide Sequencing methods, Insect Proteins genetics, Larva genetics, Lauraceae parasitology, Molecular Sequence Annotation, Plant Leaves parasitology, Reverse Transcriptase Polymerase Chain Reaction, Sequence Analysis, DNA methods, Sequence Homology, Amino Acid, Gene Expression Profiling methods, Moths genetics, Silk genetics, Transcriptome
- Abstract
Antheraea assamensis (Lepidoptera: Saturniidae), is a semi-domesticated silkworm known to be endemic to Assam and the adjoining hilly areas of Northeast India. It is the only producer of a unique, commercially important variety of golden silk called "muga silk". Herein, we report the de novo transcriptome of A. assamensis reared on Machilus bombycina leaves for the first time. Short reads generated by high throughput sequencing of cDNA libraries from multiple tissues, viz. alimentary canal, silk gland and residual body of the 5
th instar of muga silkworm were assembled into transcripts via a de novo assembly pipeline followed by functional annotation and classification. A total of 1,21,433 transcripts were generated from ~231 million raw reads of which ~74% (89,583) were either allocated a functional annotation or categorized under Pfam/COG/KEGG categories. Identification of differentially expressed transcripts and their comparative sequence analysis revealed candidate genes related to silk synthesis, viz. silk gland factor-1 and 3, sericin-like transcript, etc. with conserved forkhead, homeo- and POU domains. Several candidate anti-microbial peptides which may have potential anti-bacterial, anti-fungal or anti-parasitic activity in A. assamensis were also identified. T/A and AT/TA were predicted to be the most abundant mono- and di-nucleotide simple sequence repeat markers in the transcriptome. Transcriptome validation was carried out by quantitative real-time PCR (qPCR) amplification of eight transcripts. The resources generated by this study will expand the periphery of existing genomic data on A. assamensis facilitating future in-depth studies on its unknown aspects., (Copyright © 2017 Elsevier B.V. All rights reserved.)- Published
- 2017
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57. DNA aptamer probes for detection of estrogen receptor α positive carcinomas.
- Author
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Sett A, Borthakur BB, Sharma JD, Kataki AC, and Bora U
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- Biomarkers, Tumor, Cell Line, Tumor, Cloning, Molecular, Escherichia coli metabolism, Female, Gene Expression Regulation, Neoplastic, Humans, Aptamers, Nucleotide metabolism, Breast Neoplasms metabolism, Carcinoma diagnosis, Carcinoma metabolism, Estrogen Receptor alpha metabolism
- Abstract
Estrogen receptor alpha (ERα) also known as NR3A1 (nuclear receptor subfamily 3, group A, member 1) is a ligand-activated transcription factor. It is an important biomarker for breast cancer metastasis. In the present study, we report a novel DNA aptamer candidate against estrogen receptor (ER) alpha structure. The enriched aptamer candidate was obtained after 14 iterative cycles of in vitro protein-SELEX process. Isothermal calorimetry study suggests the nanomolar sensitivity of the candidate ER_Apt1 to its target protein. Fluorescence- and chemiluminescence-binding assays confirm the specificity of the candidate aptamer to ER alpha positive breast cancer cell line. Comparative analysis of ER_Apt1 to ER alpha monoclonal antibody was also performed to analyze the expression of ER alpha in various malignant cancer cell line. Cytochemical and immunohistochemistry assay indicates its potential use as a diagnostic agent against ERα positive carcinomas. The nucleotide aptamer sequences described in the present study can be used for the detection, treatment, prophylaxis and diagnosis of ERα-related disorder., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2017
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58. An immobilized symmetrical bis-(NHC) palladium complex as a highly efficient and recyclable Suzuki-Miyaura catalyst in aerobic aqueous media.
- Author
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Begum T, Mondal M, Borpuzari MP, Kar R, Kalita G, Gogoi PK, and Bora U
- Abstract
A bis-N-heterocyclic carbene (NHC) functionalized with chloropropyltriethoxysilane over silica was used to synthesize a well-defined immobilized palladium complex. This complex is a suitable and easily retrievable catalyst for Suzuki-Miyaura cross-coupling reactions under mild aqueous conditions. Excellent yields and conversions were obtained with low palladium loadings (down to 0.03 mol% Pd). The catalyst can be reused up to six cycles without the loss of its activity. The catalytic role of the NHC complex of palladium during coupling between bromobenzene and phenylboronic acid was investigated theoretically. The oxidative addition step is predicted to be endothermic in agreement with the experimental conditions.
- Published
- 2017
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59. Bio-inspired nano tools for neuroscience.
- Author
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Das S, Carnicer-Lombarte A, Fawcett JW, and Bora U
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- Animals, Biomimetics methods, Humans, Nervous System Diseases diagnostic imaging, Nervous System Diseases physiopathology, Nervous System Diseases therapy, Nervous System Physiological Phenomena, Neurology methods, Neurosciences methods, Biomimetic Materials, Biomimetics instrumentation, Nanostructures, Nanotechnology, Neurology instrumentation, Neurosciences instrumentation
- Abstract
Research and treatment in the nervous system is challenged by many physiological barriers posing a major hurdle for neurologists. The CNS is protected by a formidable blood brain barrier (BBB) which limits surgical, therapeutic and diagnostic interventions. The hostile environment created by reactive astrocytes in the CNS along with the limited regeneration capacity of the PNS makes functional recovery after tissue damage difficult and inefficient. Nanomaterials have the unique ability to interface with neural tissue in the nano-scale and are capable of influencing the function of a single neuron. The ability of nanoparticles to transcend the BBB through surface modifications has been exploited in various neuro-imaging techniques and for targeted drug delivery. The tunable topography of nanofibers provides accurate spatio-temporal guidance to regenerating axons. This review is an attempt to comprehend the progress in understanding the obstacles posed by the complex physiology of the nervous system and the innovations in design and fabrication of advanced nanomaterials drawing inspiration from natural phenomenon. We also discuss the development of nanomaterials for use in Neuro-diagnostics, Neuro-therapy and the fabrication of advanced nano-devices for use in opto-electronic and ultrasensitive electrophysiological applications. The energy efficient and parallel computing ability of the human brain has inspired the design of advanced nanotechnology based computational systems. However, extensive use of nanomaterials in neuroscience also raises serious toxicity issues as well as ethical concerns regarding nano implants in the brain. In conclusion we summarize these challenges and provide an insight into the huge potential of nanotechnology platforms in neuroscience., (Copyright © 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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60. A comprehensive view of the web-resources related to sericulture.
- Author
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Singh D, Chetia H, Kabiraj D, Sharma S, Kumar A, Sharma P, Deka M, and Bora U
- Subjects
- Animals, Bombyx genetics, Databases, Genetic, Internet
- Abstract
Recent progress in the field of sequencing and analysis has led to a tremendous spike in data and the development of data science tools. One of the outcomes of this scientific progress is development of numerous databases which are gaining popularity in all disciplines of biology including sericulture. As economically important organism, silkworms are studied extensively for their numerous applications in the field of textiles, biomaterials, biomimetics, etc. Similarly, host plants, pests, pathogens, etc. are also being probed to understand the seri-resources more efficiently. These studies have led to the generation of numerous seri-related databases which are extremely helpful for the scientific community. In this article, we have reviewed all the available online resources on silkworm and its related organisms, including databases as well as informative websites. We have studied their basic features and impact on research through citation count analysis, finally discussing the role of emerging sequencing and analysis technologies in the field of seri-data science. As an outcome of this review, a web portal named SeriPort, has been created which will act as an index for the various sericulture-related databases and web resources available in cyberspace.Database URL: http://www.seriport.in/., (© The Author(s) 2016. Published by Oxford University Press.)
- Published
- 2016
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61. Aptamer-Assisted Detection of the Altered Expression of Estrogen Receptor Alpha in Human Breast Cancer.
- Author
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Ahirwar R, Vellarikkal SK, Sett A, Sivasubbu S, Scaria V, Bora U, Borthakur BB, Kataki AC, Sharma JD, and Nahar P
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- Breast Neoplasms diagnosis, Breast Neoplasms metabolism, Estrogen Receptor alpha metabolism, Female, Flow Cytometry, High-Throughput Screening Assays, Humans, Immunohistochemistry, Receptors, Progesterone chemistry, Receptors, Progesterone genetics, Receptors, Progesterone metabolism, Sensitivity and Specificity, Aptamers, Nucleotide genetics, Aptamers, Nucleotide metabolism, Breast Neoplasms genetics, Estrogen Receptor alpha genetics, Gene Expression Regulation, Neoplastic, SELEX Aptamer Technique
- Abstract
An increase in the expression of estrogen receptors (ER) and the expanded population of ER-positive cells are two common phenotypes of breast cancer. Detection of the aberrantly expressed ERα in breast cancer is carried out using ERα-antibodies and radiolabelled ligands to make decisions about cancer treatment and targeted therapy. Capitalizing on the beneficial advantages of aptamer over the conventional antibody or radiolabelled ligand, we have identified a DNA aptamer that selectively binds and facilitates the detection of ERα in human breast cancer tissue sections. The aptamer is identified using the high throughput sequencing assisted SELEX screening. Biophysical characterization confirms the binding and formation of a thermodynamically stable complex between the identified DNA aptamer (ERaptD4) and ERα (Ka = 1.55±0.298×108 M(-1); ΔH = 4.32×104±801.1 cal/mol; ΔS = -108 cal/mol/deg). Interestingly, the specificity measurements suggest that the ERaptD4 internalizes into ERα-positive breast cancer cells in a target-selective manner and localizes specifically in the nuclear region. To harness these characteristics of ERaptD4 for detection of ERα expression in breast cancer samples, we performed the aptamer-assisted histochemical analysis of ERα in tissue samples from breast cancer patients. The results were validated by performing the immunohistochemistry on same samples with an ERα-antibody. We found that the two methods agree strongly in assay output (kappa value = 0.930, p-value <0.05 for strong ERα positive and the ERα negative samples; kappa value = 0.823, p-value <0.05 for the weak/moderate ER+ve samples, n = 20). Further, the aptamer stain the ERα-positive cells in breast tissues without cross-reacting to ERα-deficient fibroblasts, adipocytes, or the inflammatory cells. Our results demonstrate a significant consistency in the aptamer-assisted detection of ERα in strong ERα positive, moderate ERα positive and ERα negative breast cancer tissues. We anticipate that the ERaptD4 aptamer targeting ERα may potentially be used for an efficient grading of ERα expression in cancer tissues.
- Published
- 2016
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62. In vivo studies of silk based gold nano-composite conduits for functional peripheral nerve regeneration.
- Author
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Das S, Sharma M, Saharia D, Sarma KK, Sarma MG, Borthakur BB, and Bora U
- Subjects
- Equipment Design, Equipment Failure Analysis, Gold chemistry, Materials Testing, Metal Nanoparticles chemistry, Metal Nanoparticles ultrastructure, Nanocomposites ultrastructure, Neural Conduction physiology, Peripheral Nerve Injuries diagnosis, Recovery of Function physiology, Schwann Cells physiology, Schwann Cells transplantation, Silk ultrastructure, Tissue Scaffolds, Treatment Outcome, Guided Tissue Regeneration instrumentation, Nanocomposites chemistry, Nerve Regeneration physiology, Peripheral Nerve Injuries physiopathology, Peripheral Nerve Injuries therapy, Silk chemistry
- Abstract
We report a novel silk-gold nanocomposite based nerve conduit successfully tested in a neurotmesis grade sciatic nerve injury model in rats over a period of eighteen months. The conduit was fabricated by adsorbing gold nanoparticles onto silk fibres and transforming them into a nanocomposite sheet by electrospinning which is finally given a tubular structure by rolling on a stainless steel mandrel of chosen diameter. The conduits were found to promote adhesion and proliferation of Schwann cells in vitro and did not elicit any toxic or immunogenic responses in vivo. We also report for the first time, the monitoring of muscular regeneration post nerve conduit implantation by recording motor unit potentials (MUPs) through needle electromyogram. Pre-seeding the conduits with Schwann cells enhanced myelination of the regenerated tissue. Histo-morphometric and electrophysiological studies proved that the nanocomposite based conduits pre-seeded with Schwann cells performed best in terms of structural and functional regeneration of severed sciatic nerves. The near normal values of nerve conduction velocity (50 m/sec), compound muscle action potential (29.7 mV) and motor unit potential (133 μV) exhibited by the animals implanted with Schwann cell loaded nerve conduits in the present study are superior to those observed in previous reports with synthetic materials as well as collagen based nerve conduits. Animals in this group were also able to perform complex locomotory activities like stretching and jumping with excellent sciatic function index (SFI) and led a normal life., (Copyright © 2015 Elsevier Ltd. All rights reserved.)
- Published
- 2015
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63. Curcumin Resource Database.
- Author
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Kumar A, Chetia H, Sharma S, Kabiraj D, Talukdar NC, and Bora U
- Subjects
- Animals, Curcuma, Humans, Curcumin analogs & derivatives, Curcumin chemistry, Curcumin therapeutic use
- Abstract
Curcumin is one of the most intensively studied diarylheptanoid, Curcuma longa being its principal producer. This apart, a class of promising curcumin analogs has been generated in laboratories, aptly named as Curcuminoids which are showing huge potential in the fields of medicine, food technology, etc. The lack of a universal source of data on curcumin as well as curcuminoids has been felt by the curcumin research community for long. Hence, in an attempt to address this stumbling block, we have developed Curcumin Resource Database (CRDB) that aims to perform as a gateway-cum-repository to access all relevant data and related information on curcumin and its analogs. Currently, this database encompasses 1186 curcumin analogs, 195 molecular targets, 9075 peer reviewed publications, 489 patents and 176 varieties of C. longa obtained by extensive data mining and careful curation from numerous sources. Each data entry is identified by a unique CRDB ID (identifier). Furnished with a user-friendly web interface and in-built search engine, CRDB provides well-curated and cross-referenced information that are hyperlinked with external sources. CRDB is expected to be highly useful to the researchers working on structure as well as ligand-based molecular design of curcumin analogs., (© The Author(s) 2015. Published by Oxford University Press.)
- Published
- 2015
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64. Data in support of in vivo studies of silk based gold nano-composite conduits for functional peripheral nerve regeneration.
- Author
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Das S, Sharma M, Saharia D, Sarma KK, Sarma MG, Borthakur BB, and Bora U
- Abstract
In the present data article we report the in vitro and in vivo biocompatibility of fabricated nerve conduits described in Das et al. [1]. Green synthesised gold nanoparticles (GNPs) were evaluated for their cytotoxicity in rat Schwann cells (SCTM41). We also describe herein the adhesion and proliferation of Schwann cells over the nanofibrous scaffolds. Methods describing surgical implantation of conduits in a rat sciatic nerve injury model, confirming its accurate implantation as well as the porosity and swelling tendency of the nerve conduits are illustrated in the various figures and graphs.
- Published
- 2015
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65. Green synthesis and characterization of silver nanoparticles using alcoholic flower extract of Nyctanthes arbortristis and in vitro investigation of their antibacterial and cytotoxic activities.
- Author
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Gogoi N, Babu PJ, Mahanta C, and Bora U
- Subjects
- Animals, Cell Line, Ethanol chemistry, In Vitro Techniques, Mice, Microscopy, Electron, Transmission, Spectrophotometry, Ultraviolet, Anti-Bacterial Agents pharmacology, Antineoplastic Agents, Phytogenic pharmacology, Metal Nanoparticles, Oleaceae chemistry, Plant Extracts pharmacology, Silver chemistry
- Abstract
Here we report the synthesis of silver nanoparticles using ethanolic flower extract of Nyctanthes arbortristis, UVvisible spectra and TEM indicated the successful formation of silver nanoparticles. Crystalline nature of the silver nanoparticles was confirmed by X-ray diffraction. Fourier Transform Infra-Red Spectroscopy analysis established the capping of the synthesized silver nanoparticles with phytochemicals naturally occurring in the ethanolic flower extract of N. arbortristis. The synthesized silver nanoparticles showed antibacterial activity against the pathogenic strain of Escherichia coli MTCC 443. Furthermore, cytotoxicity of the silver nanoparticles was tested on mouse fibroblastic cell line (L929) and found to be non-toxic, which thus proved their biocompatibility. Antibacterial activity and cytotoxicity assay carried out in this study open up an important perspective of the synthesized silver nanoparticles., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2015
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66. Molecular docking studies of curcumin natural derivatives with DNA topoisomerase I and II-DNA complexes.
- Author
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Kumar A and Bora U
- Subjects
- Amino Acids, Binding Sites, Curcumin analogs & derivatives, Curcumin chemistry, Curcumin therapeutic use, DNA Cleavage, DNA Replication, Humans, Molecular Docking Simulation, Plant Extracts chemistry, Plant Extracts therapeutic use, Structure-Activity Relationship, Antigens, Neoplasm metabolism, Curcuma chemistry, Curcumin pharmacology, DNA metabolism, DNA Topoisomerases, Type I metabolism, DNA Topoisomerases, Type II metabolism, DNA-Binding Proteins metabolism, Neoplasms drug therapy, Plant Extracts pharmacology
- Abstract
DNA topoisomerase I (topo I) and II (topo II) are essential enzymes that solve the topological problems of DNA by allowing DNA strands or double helices to pass through each other during cellular processes such as replication, transcription, recombination, and chromatin remodeling. Their critical roles make topoisomerases an attractive drug target against cancer. The present molecular docking study provides insights into the inhibition of topo I and II by curcumin natural derivatives. The binding modes suggested that curcumin natural derivatives docked at the site of DNA cleavage parallel to the axis of DNA base pairing. Cyclocurcumin and curcumin sulphate were predicted to be the most potent inhibitors amongst all the curcumin natural derivatives docked. The binding modes of cyclocurcumin and curcumin sulphate were similar to known inhibitors of topo I and II. Residues like Arg364, Asn722 and base A113 (when docked to topo I-DNA complex) and residues Asp479, Gln778 and base T9 (when docked to topo II-DNA complex) seem to play important role in the binding of curcumin natural derivatives at the site of DNA cleavage.
- Published
- 2014
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67. Functional nucleic-acid-based sensors for environmental monitoring.
- Author
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Sett A, Das S, and Bora U
- Subjects
- Aptamers, Nucleotide chemistry, Environmental Pollution, Humans, Ions chemistry, Biosensing Techniques, DNA, Catalytic chemistry, Environmental Monitoring, RNA, Catalytic chemistry
- Abstract
Efforts to replace conventional chromatographic methods for environmental monitoring with cheaper and easy to use biosensors for precise detection and estimation of hazardous environmental toxicants, water or air borne pathogens as well as various other chemicals and biologics are gaining momentum. Out of the various types of biosensors classified according to their bio-recognition principle, nucleic-acid-based sensors have shown high potential in terms of cost, sensitivity, and specificity. The discovery of catalytic activities of RNA (ribozymes) and DNA (DNAzymes) which could be triggered by divalent metallic ions paved the way for their extensive use in detection of heavy metal contaminants in environment. This was followed with the invention of small oligonucleotide sequences called aptamers which can fold into specific 3D conformation under suitable conditions after binding to target molecules. Due to their high affinity, specificity, reusability, stability, and non-immunogenicity to vast array of targets like small and macromolecules from organic, inorganic, and biological origin, they can often be exploited as sensors in industrial waste management, pollution control, and environmental toxicology. Further, rational combination of the catalytic activity of DNAzymes and RNAzymes along with the sequence-specific binding ability of aptamers have given rise to the most advanced form of functional nucleic-acid-based sensors called aptazymes. Functional nucleic-acid-based sensors (FNASs) can be conjugated with fluorescent molecules, metallic nanoparticles, or quantum dots to aid in rapid detection of a variety of target molecules by target-induced structure switch (TISS) mode. Although intensive research is being carried out for further improvements of FNAs as sensors, challenges remain in integrating such bio-recognition element with advanced transduction platform to enable its use as a networked analytical system for tailor made analysis of environmental monitoring.
- Published
- 2014
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68. Posterior reversible encephalopathy syndrome in a renal transplanted patient.
- Author
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Alparslan M, Bora U, Hüseyin K, Ayhan D, and Gültekin S
- Abstract
Patient: Male, 28 FINAL DIAGNOSIS: Posterior reversible encephalopathy syndrome Symptoms: Headache • pain around umblical region • seizures • visual disturbances, Medication: Mycophenolate mofetil Clinical Procedure: Treatment of parasitosis • antiepileptic treatment • control of hypertension • changing mycophenolate mofetil to everolimus Specialty: Transplantology., Objective: Unusual or unexpected effect of treatment., Background: Posterior reversible encephalopathy syndrome (PRES) is characterized by reversible neurological findings with clinical hallmarks such as headache, confusion, seizures, cortical visual disturbances, and other focal neurological signs., Case Report: A 28-year-old male patient was hospitalized secondary to diarrhea and abdominal pain. He had renal transplantation due to renal amyloidosis secondary to familial Mediterranean fever (FMF). In his clinical follow-up, he had seizures, hemiparesis, blurred vision, and vomited an Ascaris lumbricoides. MRI results led to diagnosis of PRES. Mycophenolate mofetil was changed to everolimus, his systolic blood was pressure kept below 140 mm hg, and his intestinal parasitosis was treated. During follow-up, he had no pain and no diarrhea. His neurological symptoms turned to normal within 48 hours and neuroradiological findings returned to normal within 2 weeks., Conclusions: PRES is a rare disorder of unknown incidence in renal transplantation patients. Early diagnosis is very important to prevent irreversible neurological sequelae. PRES is totally reversible with cessation of the offending agent, rapid control of hypertension, and treatment of the underlying disease. For early diagnosis and to reduce morbidity and mortality, stool sample examination should be made in patients taking immunosuppressive drugs.
- Published
- 2013
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69. Interactions of curcumin and its derivatives with nucleic acids and their implications.
- Author
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Kumar A and Bora U
- Subjects
- Animals, Chelating Agents chemistry, Chelating Agents pharmacology, Curcuma chemistry, DNA chemistry, Humans, Mutagens chemistry, Mutagens pharmacology, Reactive Oxygen Species metabolism, Coordination Complexes analogs & derivatives, Coordination Complexes pharmacology, Curcumin analogs & derivatives, Curcumin pharmacology, DNA metabolism, Intercalating Agents chemistry, Intercalating Agents pharmacology
- Abstract
Curcumin (diferuloylmethane) is a yellow polyphenol found in the rhizome of the annual herb turmeric (Curcuma longa) belonging to the family Zingiberaceae. Its interaction with a huge number of molecular targets like cytokines, growth factors, transcription factors, receptors, pro-inflammatory enzymes, protein kinases and adhesion molecules has been studied extensively. Interaction of curcumin with nucleic acids has been the focus of extensive research in recent years. Curcumin is observed to be genotoxic and antigenotoxic agent in time and concentration dependent manner. Curcumin and its derivatives either alone or as metal complexes have been reported to bind directly to DNA. The interactions are mainly as DNA minor groove binding or as DNA intercalating agents. The similarity in the shape of curcumin to DNA minor groove binding drugs is the motivation for exploring its binding to DNA minor grooves. Thus curcumin is a "double edged sword": having therapeutic potential as a minor groove binder but at the same time it may cause DNA damage in the cell at high concentration. The purpose of this review is to summarize the current information related to interaction of curcumin metal complexes and its derivatives with nucleic acids and the implication such interaction can have on therapeutics.
- Published
- 2013
70. Differential effects of Oroxylum indicum bark extracts: antioxidant, antimicrobial, cytotoxic and apoptotic study.
- Author
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Moirangthem DS, Talukdar NC, Bora U, Kasoju N, and Das RK
- Abstract
Stem bark of Oroxylum indicum (L) (SBOI) is used by ethnic communities of North East India as health tonic and in treating diseases of humans and animals. The objective of this research was to carry out a detailed investigation including total phenolic and flavonoid content, antioxidant, antimicrobial, cytotoxic and apoptotic activities of different solvent extracts of SBOI and to establish correlation between some parameters. Among petroleum ether (PE), dichloromethane and methanol (MeOH) extract of SBOI, MeOH extract contained the highest amount of total phenolic (320.7 ± 34.6 mg Gallic acid equivalent/g extract) and flavonoid (346.6 ± 15.2 mg Quercetin equivalent/g extract) content. In vitro antioxidant activity (IC(50) 22.7 μg/ml) was highest in MeOH extract (p > 0.05) and also a significant inverse correlation was observed between phenolic (r = 0.886)/flavonoid (r = 0.764) content and corresponding DPPH IC(50). Only MeOH extract inhibited both bacteria and fungi. Although, individual extract showed cytotoxicity on HeLa cells with characteristic features of apoptosis, PE extract caused maximum cytotoxicity (IC(50) of 112.3 μg/ml, p < 0.05) and apoptotic activity (33.2 % sub-G0/G1 population) on HeLa cells. But, there was a significant non-inverse correlation of the MTT IC(50) with total phenolic (r = 0.812, p < 0.05)/flavonoid (r = 0.998, p < 0.05) content in the three solvent extracts. TLC analysis showed three unique compounds in PE extract which may have a role in apoptosis mediated cytotoxicity. These results called for futher chemical characterisation of MeOH and PE extract of SBOI for specific bioactivity.
- Published
- 2013
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71. Fabrication and characterization of curcumin-releasing silk fibroin scaffold.
- Author
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Kasoju N and Bora U
- Subjects
- Animals, Bombyx, Delayed-Action Preparations, Hydrophobic and Hydrophilic Interactions, Kinetics, Porosity, Anti-Infective Agents chemistry, Anti-Infective Agents pharmacokinetics, Antineoplastic Agents chemistry, Antineoplastic Agents pharmacokinetics, Antioxidants chemistry, Antioxidants pharmacokinetics, Curcumin chemistry, Curcumin pharmacokinetics, Fibroins chemistry, Models, Chemical
- Abstract
Here, we report the fabrication of a curcumin-releasing porous silk fibroin scaffold by simple mixing of fibroin solution (aqueous) with curcumin solution (organic) followed by freeze-thaw of the mixture. The scaffold has a uniform pore distribution with an average pore size of ~115 μm and a degree of swelling of 2.42% and water uptake capacity of 70.81%. Fibroin showed thermal stability up to ~280°C, whereas encapsulated curcumin disintegrated at ~180°C. Fourier transform infrared, powder X-ray diffraction, and nuclear magnetic resonance studies together with UV-visible and fluorescence spectroscopy investigations revealed the solvent (which was used to dissolve curcumin) induced conformational transition of fibroin from silk-I to silk-II that led to the formation of water-stable structure. Fluorescence spectroscopy data also suggested the presence of hydrophobic domains in fibroin and encapsulation of curcumin in such domains through hydrophobic interactions. Release kinetics and mathematical modeling studies indicated a slow and sustained release profile with diffusion as the predominant mode of release. Further, in vitro anticancer, antioxidant, and antimicrobial assays suggested that the biological activity of encapsulated curcumin remains unaltered. The fabrication process is simple, reproducible, and does not require any sophisticated instruments or toxic crosslinking agents. It is anticipated that the curcumin-loaded fibroin scaffold could be used in soft tissue replacements including localized postsurgical chemotherapy against tumors, dressing material for quick healing of wounds and burns, and other related applications., (Copyright © 2012 Wiley Periodicals, Inc.)
- Published
- 2012
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72. Silk fibroin based biomimetic artificial extracellular matrix for hepatic tissue engineering applications.
- Author
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Kasoju N and Bora U
- Subjects
- Animals, Biomimetics, Bombyx, Cell Line, Cell Proliferation, Cell Survival, Chitosan chemistry, Galactose chemistry, Hep G2 Cells, Hepatocytes cytology, Humans, Mice, Polyethylene Glycols chemistry, Spectroscopy, Fourier Transform Infrared methods, Thermogravimetry methods, X-Ray Diffraction, Extracellular Matrix metabolism, Fibroins chemistry, Liver metabolism, Silk metabolism, Tissue Engineering methods
- Abstract
Hepatic tissue engineering, which aims to construct artificial liver tissues, requires a suitable extracellular matrix (ECM) for growth and proliferation of metabolically active hepatocytes. The current paper describes the development of a biomimetic artificial ECM, for hepatic tissue engineering applications, by mimicking the architectural features and biochemical composition of native ECM. Electrospinning was chosen as the fabrication technique of choice, while regenerated silk fibroin (RSF) and galactosylated chitosan (GalCS) were chosen as materials of choice. Poly(ethylene oxide) was used as a processing aid. Methodical optimization studies were performed to obtain smooth and continuous nanofibers with homogenous size distribution. Extensive characterization studies were performed to determine its morphological, physical, chemical/structural, thermal and cytotoxicity properties. Subsequently, detailed in vitro hepatocyte compatibility studies were performed using HepG2 cell line. Remarkably, the studies revealed that the growth, viability, metabolic activity and proliferation of hepatocytes were relatively superior on RSF-GalCS scaffold than on pure RSF and pure GalCS. In summary, the electrospun nanofibrous RSF-GalCS scaffold tries to mimic both architectural and biochemical features of native ECM, and hence could be an appropriate scaffold for in vitro engineering of hepatic tissue. However, additional experiments are needed to confirm the superiority in characteristic functionality of hepatocytes growing on RSF-GalCS scaffold in relation to RSF and GalCS scaffolds, and to test its behavior in vivo.
- Published
- 2012
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73. Silk fibroin in tissue engineering.
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Kasoju N and Bora U
- Subjects
- Bioprinting instrumentation, Biocompatible Materials chemistry, Bioprinting methods, Fibroins chemistry, Fibroins ultrastructure, Tissue Engineering methods, Tissue Scaffolds
- Abstract
Tissue engineering (TE) is a multidisciplinary field that aims at the in vitro engineering of tissues and organs by integrating science and technology of cells, materials and biochemical factors. Mimicking the natural extracellular matrix is one of the critical and challenging technological barriers, for which scaffold engineering has become a prime focus of research within the field of TE. Amongst the variety of materials tested, silk fibroin (SF) is increasingly being recognized as a promising material for scaffold fabrication. Ease of processing, excellent biocompatibility, remarkable mechanical properties and tailorable degradability of SF has been explored for fabrication of various articles such as films, porous matrices, hydrogels, nonwoven mats, etc., and has been investigated for use in various TE applications, including bone, tendon, ligament, cartilage, skin, liver, trachea, nerve, cornea, eardrum, dental, bladder, etc. The current review extensively covers the progress made in the SF-based in vitro engineering and regeneration of various human tissues and identifies opportunities for further development of this field., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)
- Published
- 2012
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74. Antioxidant, antibacterial, cytotoxic, and apoptotic activity of stem bark extracts of Cephalotaxus griffithii Hook. f.
- Author
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Moirangthem DS, Talukdar NC, Kasoju N, and Bora U
- Subjects
- Antineoplastic Agents, Phytogenic pharmacology, Flavonoids analysis, Flavonoids pharmacology, Flavonoids therapeutic use, HeLa Cells, Humans, Phenols analysis, Phenols pharmacology, Phenols therapeutic use, Plant Bark, Plant Stems, Anti-Bacterial Agents pharmacology, Antineoplastic Agents, Phytogenic therapeutic use, Antioxidants pharmacology, Apoptosis drug effects, Cephalotaxus chemistry, Phytotherapy, Plant Extracts chemistry, Plant Extracts pharmacology, Plant Extracts therapeutic use
- Abstract
Background: Cephalotaxus spp. are known to possess various therapeutic potentials. Cephalotaxus griffithii, however, has not been evaluated for its biological potential. The reason may be the remoteness and inaccessibility of the habitat where it is distributed. The main aim of this study was to: (1) evaluate multiple biological potentials of stem bark of C. griffithii, and (2) identify solvent extract of stem bark of C. griffithii to find the one with the highest specific biological activity., Methods: Dried powder of stem bark of C. griffithii was exhaustively extracted serially by soaking in petroleum ether, acetone and methanol to fractionate the chemical constituents into individual fractions or extracts. The extracts were tested for total phenolic and flavonoid content, antioxidant (DPPH radical scavenging, superoxide radical scavenging, and reducing power models), antibacterial (disc diffusion assay on six bacterial strains), cytotoxic (MTT assay on HeLa cells), and apoptotic activity (fluorescence microscopy, DNA fragmentation assay, and flow cytometry on HeLa cells)., Results: Among the three extracts of stem bark of C. griffithii, the acetone extract contained the highest amount of total phenolics and flavonoids and showed maximum antioxidant, antibacterial, cytotoxic (IC50 of 35.5 ± 0.6 μg/ml; P < 0.05), and apoptotic (46.3 ± 3.6% sub-G0/G1 population; P < 0.05) activity, followed by the methanol and petroleum ether extracts. However, there was no significant difference observed in IC50 values (DPPH scavenging assay) of the acetone and methanol extracts and the positive control (ascorbic acid). In contrast, superoxide radical scavenging assay-based antioxidant activity (IC50) of the acetone and methanol extracts was significantly lower than the positive control (P < 0.05). Correlation analysis suggested that phenolic and flavonoid content present in stem bark of C. griffithii extracts was responsible for the high antioxidant, cytotoxic, and apoptotic activity (P < 0.05)., Conclusions: Stem bark of C. griffithii has multiple biological effects. These results call for further chemical characterization of acetone extract of stem bark of C. griffithii for specific bioactivity.
- Published
- 2012
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75. Microwave-mediated enzyme-linked immunosorbent assay procedure.
- Author
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Nahar P, Bora U, Sharma GL, and Kannoujia DK
- Subjects
- Animals, Humans, Immunoglobulins analysis, Rabbits, Enzyme-Linked Immunosorbent Assay methods, Microwaves
- Abstract
Here we demonstrate a novel microwave-mediated enzyme-linked immunosorbent assay (MELISA) method that has dramatically reduced the enzyme-linked immunosorbent assay (ELISA) timing to less than 5 min with a result comparable to that obtained by 18-h conventional ELISA. Efficacy of the MELISA procedure is demonstrated by detecting human immunoglobulin G (IgG), rabbit IgG, human immunoglobulin E (IgE), human interleuken 1β (IL-1β), Entamoeba histolytica antibody, and Aspergillus fumigatus antibody. MELISA could be an excellent substitute for time-consuming conventional ELISA for rapid diagnosis of diseases in cases of medical urgency, outbreak of infectious diseases, and screening of samples in blood banks or emigration counters., (Copyright © 2011 Elsevier Inc. All rights reserved.)
- Published
- 2012
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76. In Silico Inhibition Studies of Jun-Fos-DNA Complex Formation by Curcumin Derivatives.
- Author
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Kumar A and Bora U
- Abstract
Activator protein-1 (AP1) is a transcription factor that consists of the Jun and Fos family proteins. It regulates gene expression in response to a variety of stimuli and controls cellular processes including proliferation, transformation, inflammation, and innate immune responses. AP1 binds specifically to 12-O-tetradecanoylphorbol-13-acetate (TPA) responsive element 5'-TGAG/CTCA-3' (AP1 site). It has been found constitutively active in breast, ovarian, cervical, and lung cancers. Numerous studies have shown that inhibition of AP1 could be a promising strategy for cancer therapeutic applications. The present in silico study provides insights into the inhibition of Jun-Fos-DNA complex formation by curcumin derivatives. These derivatives interact with the amino acid residues like Arg155 and Arg158 which play a key role in binding of Jun-Fos complex to DNA (AP1 site). Ala151, Ala275, Leu283, and Ile286 were the residues present at binding site which could contribute to hydrophobic contacts with inhibitor molecules. Curcumin sulphate was predicted to be the most potent inhibitor amongst all the natural curcumin derivatives docked.
- Published
- 2012
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77. Molecular docking studies on inhibition of Stat3 dimerization by curcumin natural derivatives and its conjugates with amino acids.
- Author
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Kumar A and Bora U
- Abstract
Stat3 is a mammalian transcription factor which regulates various genes involved in cell growth, proliferation, cell survival and other biological processes. Its constitutive activation promotes dysregulated growth, survival and immune responses which contribute to tumor progression and carcinogenesis. Inhibition of Stat3 dimerization which prevents its binding to DNA is a rational strategy that could be translated to potential therapeutic applications. The present computational study provides insights into the inhibition of Stat3 dimerization by curcumin natural derivatives and its conjugates with amino acids. The involvement of residues like LYS-591, ARG-609, SER-611, GLU-612, SER-613, SER-636 and VAL-637 seems to play an important role in binding of curcumin natural derivatives and its amino acids conjugates with Src Homology (SH2) domain of Stat3 monomer. Demethoxycurcumin followed by hexahydrocurcuminol were predicted to be the most potent inhibitors amongst all the curcumin natural derivatives and known inhibitors (FLLL32, Sta21 and Stattic). Curcumin-proline conjugate (1,7-Bis(4-O-L-prolinoyl-3- methoxyphenyl)-1,4,6-heptatriene-5-ol-3-one) was predicted to be the most potent inhibitor of Stat3 dimerization amongst the curcumin-amino acid conjugates and known peptide based inhibitor (Phpr-pTYR-LEU-cis-3,4-methanoPRO-GLN-NHBn).
- Published
- 2012
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78. Green synthesis of gold nanoparticles using Nyctanthes arbortristis flower extract.
- Author
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Das RK, Gogoi N, and Bora U
- Subjects
- Chlorides chemistry, Flowers chemistry, Gold Compounds chemistry, Microscopy, Electron, Transmission, Oleaceae chemistry, Spectrophotometry, Ultraviolet, Spectroscopy, Fourier Transform Infrared, X-Ray Diffraction, Gold chemistry, Green Chemistry Technology methods, Metal Nanoparticles chemistry, Plant Extracts chemistry
- Abstract
The present study explores the reducing and capping potentials of ethanolic flower extract of the plant Nyctanthes arbortristis for the synthesis of gold nanoparticles. The extract at different volume fractions were stirred with HAuCl4 aqueous solution at 80 °C for 30 min. The UV-Vis spectroscopic analysis of the reaction products confirmed successful reduction of Au(3+) ions to gold nanoparticles. Transmission electron microscope (TEM) revealed dominant spherical morphology of the gold nanoparticles with an average diameter of 19.8 ± 5.0 nm. X-ray diffraction (XRD) study confirmed crystalline nature of the synthesized particles. Fourier transform infra-red (FTIR) and nuclear magnetic resonance (NMR) analysis of the purified and lyophilized gold nanoparticles confirmed the surface adsorption of biomolecules during preparation and caused long-term (6 months) stability. Low reaction temperature (25 °C) favored anisotropy. The strong reducing power of the flower extract can also be tested in the green synthesis of other metallic nanoparticles.
- Published
- 2011
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79. Encapsulation of curcumin in Pluronic block copolymer micelles for drug delivery applications.
- Author
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Sahu A, Kasoju N, Goswami P, and Bora U
- Subjects
- Cell Death drug effects, Cell Line, Tumor, Cell Survival drug effects, Curcumin chemistry, Excipients analysis, HeLa Cells, Humans, Microscopy, Atomic Force, Models, Theoretical, Poloxamer analysis, Spectrometry, Fluorescence, Spectroscopy, Fourier Transform Infrared, X-Ray Diffraction, Curcumin administration & dosage, Excipients chemistry, Micelles, Nanocapsules analysis, Nanocapsules chemistry, Nanocapsules ultrastructure, Poloxamer chemistry
- Abstract
We report here the potential of Pluronic tri-block copolymer micelles for the formulation of curcumin, a natural dietary compound having great therapeutic potential against many diseases including cancer. Two most commonly used Pluronic F127 and F68 were used for the formulation and analyzed for curcumin encapsulation efficiency and stability. The encapsulation of drug in micelle was highly dependent on drug-to-copolymer ratio. Pluronic F127 showed better encapsulation efficiency than Pluronic F68. In vitro release profile demonstrated slower and sustained release of curcumin from Pluronic micelles. The lyophilized form of the formulations exhibited good stability for long-term storage. The physical interaction of curcumin with Pluronic was evident by XRD analysis, UV-visible, fluorescence, and FT-IR spectroscopy. AFM study showed that the drug-encapsulated micelles were spherical in shape with diameters below 100 nm. The in vitro cytotoxicity of the drug formulations was investigated with HeLa cancer cells. Pluronic-encapsulated curcumin showed comparable anticancer activity with free curcumin.
- Published
- 2011
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80. Improving the standards of scientific publishing in India.
- Author
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Kasoju N and Bora U
- Subjects
- India, Publishing economics, Periodicals as Topic standards, Periodicals as Topic statistics & numerical data, Publishing standards
- Published
- 2010
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81. Structural analysis and biomedical applications of dextran produced by a new isolate Pediococcus pentosaceus screened from biodiversity hot spot Assam.
- Author
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Patel S, Kasoju N, Bora U, and Goyal A
- Subjects
- Biodiversity, Dextrans pharmacology, HeLa Cells, Humans, Magnetic Resonance Spectroscopy, Rheology, Spectroscopy, Fourier Transform Infrared, Dextrans biosynthesis, Pediococcus metabolism
- Abstract
Dextran produced by a natural isolate of Pediococcus pentosaceus, screened from Assam, in the Northeastern region of India, was estimated, purified, structure characterised and functionality analysed. The dextran concentration in the cell free supernatant of the isolate P. pentosaceus was 10.2mg/ml. FT-IR analysis revealed the hydroxyl and carboxyl functional groups present in the dextran. (1)H NMR and (13)C NMR spectral data revealed that the dextran has a linear backbone of alpha-(1-->6) linked D-glucose residues. The decrease in viscosity of dextran solution with the increase in shear rate, threw light on its typical non-Newtonian pseudoplastic behaviour. The cytotoxicity tests on human cervical cancer (HeLa) cell line was studied which showed the dextran is non-toxic and biocompatible, rendering it safe for drug delivery, tissue engineering and various other biomedical applications., ((c) 2010 Elsevier Ltd. All rights reserved.)
- Published
- 2010
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82. Encapsulation of curcumin in alginate-chitosan-pluronic composite nanoparticles for delivery to cancer cells.
- Author
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Das RK, Kasoju N, and Bora U
- Subjects
- Cell Death drug effects, Cell Survival drug effects, Glucuronic Acid chemistry, HeLa Cells, Hexuronic Acids chemistry, Humans, Kinetics, Microscopy, Fluorescence, Nanocomposites chemistry, Nanoparticles ultrastructure, Particle Size, Spectroscopy, Fourier Transform Infrared, Alginates chemistry, Chitosan chemistry, Curcumin pharmacology, Drug Delivery Systems methods, Nanoparticles chemistry, Neoplasms metabolism, Poloxamer chemistry
- Abstract
We report a nanoformulation of curcumin with a tripolymeric composite for delivery to cancer cells. The composite nanoparticles (NPs) were prepared by using three biocompatible polymers-alginate (ALG), chitosan (CS), and pluronic-by ionotropic pre-gelation followed by polycationic cross-linking. Pluronic F127 was used to enhance the solubility of curcumin in the ALG-CS NPs. Atomic force and scanning electron microscopic analysis showed that the particles were nearly spherical in shape with an average size of 100 +/- 20 nm. Fourier transform-infrared analysis revealed potential interactions among the constituents in the composite NPs. Encapsulation efficiency (%) of curcumin in composite NPs showed considerable increase over ALG-CS NPs without pluronic. The in vitro drug release profile along with release kinetics and mechanism from the composite NPs were studied under simulated physiological conditions for different incubation periods. A cytotoxicity assay showed that composite NPs at a concentration of 500 microg/mL were nontoxic to HeLa cells. Cellular internalization of curcumin-loaded composite NPs was confirmed from green fluorescence inside the HeLa cells. The half-maximal inhibitory concentrations for free curcumin and encapsulated curcumin were found to be 13.28 and 14.34 muM, respectively., From the Clinical Editor: A nanoformulation of curcumin with a tri-component polymeric composite for delivery to cancer cells is reported in this paper. Cellular internalization of curcumin loaded composite nanoparticles was confirmed from green fluorescence inside the HeLa cells., (Copyright 2010 Elsevier Inc. All rights reserved.)
- Published
- 2010
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83. Preparation and characterization of Antheraea assama silk fibroin based novel non-woven scaffold for tissue engineering applications.
- Author
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Kasoju N, Bhonde RR, and Bora U
- Subjects
- Animals, Blood Platelets metabolism, Cell Line, Tumor, Cell Movement, Chorioallantoic Membrane metabolism, HeLa Cells, Humans, Neovascularization, Pathologic, Protein Structure, Secondary, Spectroscopy, Fourier Transform Infrared methods, Stress, Mechanical, Fibroins chemistry, Moths metabolism, Silk chemistry, Tissue Engineering methods
- Abstract
The quest for novel materials as scaffolds with suitable micro-architecture for supporting tissue neogenesis in tissue engineering and regenerative medicine (TERM) is continuing. In this paper we report an Antheraea assama silk-based non-woven fibroin scaffold for applications in TERM. The novel three-dimensional scaffold is highly interconnected and porous, with a pore size of 150 microm, porosity of 90% and water uptake capacity of 85%. FTIR revealed a typical beta-sheet structure of fibroin. The scaffold has thermal and mechanical properties superior to those of Bombyx mori, as revealed by DSC, TGA and tensile tests. The scaffold exhibited satisfactory blood compatibility, as determined by thrombogenicity, haemolysis, platelet/leukocyte count, platelet adhesion and protein adsorption studies. The scaffold was found to be cytocompatible with human cell lines A549, KB, HepG2 and HeLa for a period of up to 4 weeks. SEM analysis revealed excellent attachment, spreading and migration of cells in the scaffold. MTT assay was performed to estimate the viability and growth of cells in the matrix. Quantification of collagen in cell-scaffold constructs was done by picro-Sirius red assay. Ex ovo chorioallantoic membrane assay and nitric oxide estimations in spent culture medium showed the scaffold's ability to promote angiogenesis. Finally, the biodegradability of the scaffold was determined by the weight loss observed upon treatment with trypsin over a period of 4 weeks. The results reveal that the fibroin from A. assama is a promising candidate as a biocompatible, biomimetic and biodegradable biomaterial of natural origin for applications in TERM., (Copyright (c) 2009 John Wiley & Sons, Ltd.)
- Published
- 2009
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84. Microwave mediated rapid synthesis of chitosan.
- Author
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Sahu A, Goswami P, and Bora U
- Subjects
- Acetylation radiation effects, Biocompatible Materials chemistry, Biocompatible Materials radiation effects, Chitin chemistry, Chitin radiation effects, Chitosan chemistry, Chitosan radiation effects, Microwaves, Molecular Structure, Ninhydrin, Spectroscopy, Fourier Transform Infrared, X-Ray Diffraction, Biocompatible Materials chemical synthesis, Chitosan chemical synthesis
- Abstract
Chitosan is synthesized by deacetylating chitin with NaOH solution under microwave irradiation. The process describes a rapid synthesis procedure in comparison to conventional methods. The microwave-synthesized chitosan was characterized by Ninhydrin test, Fourier transform-infrared spectroscopy and X-ray diffraction measurements. The experimental results show that the degree of deacetylation increased with increasing irradiation time. A degree of deacetylation of 85.3% was achieved after irradiating chitin with 45% NaOH solution in a microwave for 5.5 min at 900-watt power. This method can be very useful for synthesizing low molecular weight chitosan with rapid and clean chemistry.
- Published
- 2009
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85. Synthesis of novel biodegradable and self-assembling methoxy poly(ethylene glycol)-palmitate nanocarrier for curcumin delivery to cancer cells.
- Author
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Sahu A, Bora U, Kasoju N, and Goswami P
- Subjects
- Catalysis, Cell Line, Tumor, HeLa Cells, Humans, Hydrogen-Ion Concentration, Inhibitory Concentration 50, Micelles, Microscopy, Confocal, Scattering, Radiation, Biocompatible Materials chemistry, Curcumin chemistry, Drug Delivery Systems, Nanoparticles chemistry, Nanotechnology methods, Polyethylene Glycols chemistry
- Abstract
A novel polymeric amphiphile, mPEG-PA, was synthesized with methoxy poly(ethylene glycol) (mPEG) as the hydrophilic and palmitic acid (PA) as the hydrophobic segment. The conjugate prepared in a single-step reaction showed minimal toxicity on HeLa cells. (1)H nuclear magnetic resonance imaging and Fourier transform infrared spectroscopy revealed that the conjugation was through an ester linkage, which is biodegradable. Enzymes having esterase activity, such as lipase, can degrade the conjugate easily, as observed by in vitro studies. mPEG-PA conjugate undergoes self-assembly in an aqueous environment, as evidenced by fluorescence spectroscopic studies with pyrene as a probe. The mPEG-PA conjugate formed micelles in the aqueous solution with critical micelle concentration of 0.12 g l(-1). Atomic force microscopy and dynamic light scattering studies showed that the micelles were spherical in shape, with a mean diameter of 41.43 nm. The utility of mPEG-PA to entrap the potent chemopreventive agent curcumin in the core of nanocarrier was investigated. The encapsulation of a highly hydrophobic compound like curcumin in the nanocarrier makes the drug readily soluble in an aqueous system, which can increase the ease of dosing and makes intravenous dosing possible. Drug-loaded micelle nanoparticles showed good stability in physiological condition (pH 7.4), in simulated gastric fluid (pH 1.2) and in simulated intestinal fluid (pH 6.8). This micellar formulation can be used as an enzyme-triggered drug release carrier, as suggested by in vitro enzyme-catalyzed drug release using pure lipase and HeLa cell lysate. The IC(50) of free curcumin and encapsulated curcumin was found to be 14.32 and 15.58 microM, respectively.
- Published
- 2008
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86. Fluorescence study of the curcumin-casein micelle complexation and its application as a drug nanocarrier to cancer cells.
- Author
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Sahu A, Kasoju N, and Bora U
- Subjects
- Cell Survival, HeLa Cells, Humans, Microscopy, Atomic Force, Models, Chemical, Molecular Conformation, Nanoparticles chemistry, Protein Binding, Time Factors, Caseins chemistry, Curcumin chemistry, Drug Carriers, Micelles, Microscopy, Fluorescence methods, Neoplasms drug therapy
- Abstract
In milk caseins exists a natural nanostructure, which can be exploited as a carrier of hydrophobic drugs. Here we investigated the complex formation of curcumin with bovine casein micelles (CMs) and its use as a vehicle for drug delivery to cancer cells. DLS studies of the CM suspension that was stable in buffer solution (pH 7.4) showed an average size distribution of <200 nm. SEM and AFM studies showed that the particles were roughly spherical in shape. Steady-state fluorescence spectroscopy of the CM-curcumin complex formation revealed that curcumin molecules formed complexes with CMs (CM-curcumin complex) through hydrophobic interactions. The binding constant for the CM-curcumin interaction was calculated to be 1.48 x 10(4) M(-1), as determined by the curcumin fluorescence. Fluorescence quenching showed that curcumin molecules quench the intrinsic fluorescence of caseins upon binding. We evaluated the utility of CMs as carriers of curcumin by using in vitro cultured HeLa cells. Cytotoxicity studies of HeLa cells revealed that the IC50 of free curcumin and the CM-curcumin complex was 14.85 and 12.69 microM, respectively.
- Published
- 2008
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87. Medicinal plants used by the people of Northeast India for curing malaria.
- Author
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Bora U, Sahu A, Saikia AP, Ryakala VK, and Goswami P
- Subjects
- Antimalarials administration & dosage, Antimalarials chemistry, Antimalarials pharmacology, Databases, Factual, Ethnobotany, Humans, India epidemiology, Malaria epidemiology, Plant Bark chemistry, Plant Extracts chemistry, Plant Extracts pharmacology, Plant Roots chemistry, Malaria drug therapy, Phytotherapy statistics & numerical data, Plants, Medicinal
- Abstract
The present study showed that the people of the Northeastern region of India use at least 65 plants belonging to 38 families to treat malaria. Different plant parts such as the leaf, root, bark and fruit and in some cases the whole plant were used for making the herbal preparations. All crude preparations were made using water as the medium. The preparations were orally administered either as a plant crude extract, juice and decoction or leaf infusion. Of the 65 plants, 21 were found to be used in the form of a decoction. The hard parts of the herbs such as the root and bark were taken in the form of a decoction. In some cases the ingredients of the herbal preparation also included honey or sugar. The present investigation also indicated that most of the preparations made for curing malaria were derived from single plant sources., ((c) 2007 John Wiley & Sons, Ltd.)
- Published
- 2007
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88. Heterogeneous Pd/C-catalyzed ligand-free, room-temperature Suzuki-Miyaura coupling reactions in aqueous media.
- Author
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Maegawa T, Kitamura Y, Sako S, Udzu T, Sakurai A, Tanaka A, Kobayashi Y, Endo K, Bora U, Kurita T, Kozaki A, Monguchi Y, and Sajiki H
- Subjects
- Boronic Acids chemistry, Carbon chemistry, Catalysis, Hydrocarbons, Halogenated chemistry, Ligands, Methane analogs & derivatives, Methane chemistry, Molecular Structure, Solvents chemistry, Temperature, Vinyl Compounds chemistry, Water chemistry, Palladium chemistry
- Abstract
A mild and efficient ligand-free Suzuki-Miyaura coupling reaction catalyzed by heterogeneous Pd/C was developed. Aryl bromides and triflates undergo the cross-coupling with aryl boronic acids in excellent yields without the presence of any additives in aqueous media at room temperature. Aryl vinyl boronic acids are also applicable to this coupling reaction and provide the trans-stilbene derivatives in high yields. The application of wet-type Pd/C to the coupling reaction was achieved without any loss of activity under aerobic conditions, and the reuse of Pd/C is feasible for a fifth run without significant loss of activity. Inductively coupled plasma (ICP) mass-spectrometric analysis of the filtrate from the reaction mixture of 4-bromonitrobenzene with phenylboronic acid demonstrated that the palladium metal hardly leached into the solution within the limits of the detector (<1 ppm), thus suggesting that the present Suzuki-Miyaura reaction proceeded by heterogeneous catalysis.
- Published
- 2007
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89. Photoreactive cellulose membrane--A novel matrix for covalent immobilization of biomolecules.
- Author
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Bora U, Sharma P, Kannan K, and Nahar P
- Subjects
- Adsorption, Biopolymers analysis, Enzyme-Linked Immunosorbent Assay instrumentation, Enzymes, Immobilized analysis, Materials Testing, Ultraviolet Rays, Biopolymers chemistry, Cellulose chemistry, Cellulose radiation effects, Enzyme-Linked Immunosorbent Assay methods, Enzymes, Immobilized chemistry, Membranes, Artificial, Photochemistry methods
- Abstract
We report a simple and mild procedure for the preparation of a photoreactive cellulose membrane capable of forming a covalent bond with a biomolecule in presence of 365 nm UV light. Photoreactive cellulose membrane was prepared by the reaction of fluoro group of 1-fluoro-2-nitro-4-azidobenzene (FNAB) and hydroxyl group of the cellulose in an alkaline medium. X-ray photoelectron spectroscopy (XPS) of the photoreactive cellulose confirmed the incorporation of FNAB moiety. Azido group of the photoreactive membrane on exposure to UV light transforms into highly reactive nitrene which binds with a protein. The efficacy of the activated membrane was checked by immobilizing glucose oxidase (GOD) onto it in presence of light. Immobilized GOD was found to have improved thermal, pH and storage stability. Photoreactive cellulose membrane was successfully used in enzyme-linked immunosorbent assay (ELISA) technique. The antibody immobilized onto such support by UV irradiation in 30 min showed similar ELISA value than the antibody immobilized onto a polystyrene ELISA plate in 12h incubation at 4 degrees C by conventional method.
- Published
- 2006
- Full Text
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90. Photochemical activation of a polycarbonate surface for covalent immobilization of a protein ligand.
- Author
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Bora U, Sharma P, Kumar S, Kannan K, and Nahar P
- Abstract
Polycarbonate-a thermostable polymer is activated by a simple and rapid method using a photolinker, 1-fluoro-2-nitro-4-azidobenzene (FNAB) for covalent immobilization of a biomolecule. Horseradish peroxidase (HRP) is used as a model enzyme to check the efficacy of the activated surface. HRP is immobilized on the activated polycarbonate surface without addition of any reagent or catalyst and is found to give 2-2.5-fold increase in absorbance with the substrate as compared to the directly adsorbed enzyme. Photochemical attachment of FNAB to the PC surface is confirmed by X-ray photoelectron spectroscopy (XPS), which shows the presence of nitrogen and fluorine in the ratio of 2:1 in the activated polycarbonate. Disappearance of fluorine peak in the XP spectra of PC bound enzyme further confirms the covalent binding of HRP, through displacement of fluorine moiety of the activated PC by the amino group of the protein. Optimized concentration of the photolinker is found as 6mumol of FNAB per well and time of photo irradiation is 8min for activation of a PCR polycarbonate plate. PC bound HRP has shown enhanced thermal and storage stability. Kinetic studies of the immobilized HRP shows improved catalytic activity. The potential application of activated polycarbonate surface includes immobilization of biomolecules for biosensors, immunoassays, and protein and DNA micro-arrays. Due to the stability of the polycarbonate at high temperature, the activated polycarbonate has an advantage for immobilization of thermostable biomolecule such as thermostable enzyme for reaction at elevated temperature.
- Published
- 2006
- Full Text
- View/download PDF
91. Ethnobotany of medicinal plants used by Assamese people for various skin ailments and cosmetics.
- Author
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Saikia AP, Ryakala VK, Sharma P, Goswami P, and Bora U
- Subjects
- Administration, Oral, Administration, Topical, Ethnobotany, Humans, India, Plant Preparations administration & dosage, Cosmetics, Curcuma, Medicine, Traditional, Melia azedarach, Phytotherapy, Plant Preparations therapeutic use, Skin Diseases drug therapy
- Abstract
The present paper deals with the medicinal plants used by the people of Assam for curing different skin ailments and for cosmetics. A total of 85 plants belonging to 49 families have been documented for their therapeutic use against skin diseases and as herbal care. The herbal medicines were prepared from various plant parts of single plant, or multiple plants. The majority of the preparation was made using water as the medium. The mode of application was topical, but in many cases it was also administered orally. In several cases the pure herbal preparations was administered along with milk, ghee, honey, coconut oil, curd, etc. Remedies for 18 skin ailments were documented through this study. About 14 plants are known for their use to cure multiple skin diseases. Among these Curcuma longa and Melia azaderach constitute the major plants. The herbal cosmetic products used by the people of Assam ranges from the enhancement of skin colour, hair care, removal of ugly spots, colouring of nails, palms, and teeth. However, many of the plant preparations used for enhancing beauty were also applied for therapeutic use. Herbal remedies were also available for skin burns, prickly heat and pimples. Information on nine plants used for managing dry skin also emerged from this study.
- Published
- 2006
- Full Text
- View/download PDF
92. Heat-mediated enzyme-linked immunosorbent assay procedure on a photoactivated surface.
- Author
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Bora U, Kannan K, and Nahar P
- Subjects
- Animals, Enzyme-Linked Immunosorbent Assay methods, Goats immunology, Hot Temperature, Humans, Immunoglobulin E immunology, Immunoglobulin G immunology, Polystyrenes, Time Factors, Clinical Laboratory Techniques
- Abstract
The human burden of infectious and allergic disease has necessitated rapid screening and measurement of antibodies in sera. Here, we report an enhancement of speed and sensitivity of an enzyme-linked immunosorbent assay (ELISA) technique by performing it at elevated temperature on an activated surface. The activated polymer was able to bind covalently anti-human IgG at 50 degrees C over 40 min to form a solid phase. The covalently bound solid phase was stable enough to withstand subsequent ELISA steps at elevated temperature. Thus, when blocking, human IgG and antibody-enzyme conjugate binding were performed on this solid phase at 40 degrees C in 40 min, 50 degrees C in 45 min and 50 degrees C in 40 min, respectively. The ELISA readings obtained were 1.5-fold higher than those obtained at 37 degrees C over similar incubation times. Total IgE was also determined by the heat-mediated ELISA (HELISA) technique in less than 3 h and gave similar ELISA values to those obtained by the conventional procedure carried out for 18 h on an untreated surface. A stable covalently bound solid phase is a prerequisite for the HELISA technique and was further verified when a solid phase prepared through adsorption onto an untreated surface showed less than half the ELISA absorbance values obtained with the activated surface at elevated temperatures. As surface activation can be achieved by application of a simple technique, the HELISA procedure could be a powerful alternative to conventional ELISA.
- Published
- 2004
- Full Text
- View/download PDF
93. Microwave-mediated rapid immobilization of enzymes onto an activated surface through covalent bonding.
- Author
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Nahar P and Bora U
- Subjects
- Glucose Oxidase metabolism, Horseradish Peroxidase metabolism, Horseradish Peroxidase radiation effects, Time Factors, Urease metabolism, Glucose Oxidase radiation effects, Microwaves, Polystyrenes metabolism, Urease radiation effects
- Published
- 2004
- Full Text
- View/download PDF
94. Covalent immobilization of proteins onto photoactivated polystyrene microtiter plates for enzyme-linked immunosorbent assay procedures.
- Author
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Bora U, Chugh L, and Nahar P
- Subjects
- Animals, Goats, Immunoglobulin E analysis, Immunoglobulin G immunology, Photochemistry, Polystyrenes, Rabbits, Enzyme-Linked Immunosorbent Assay methods
- Abstract
Enhancement of the speed and sensitivity of an ELISA technique was achieved by doing it on a polystyrene microtiter plate preactivated by a simple photochemical reaction. Immobilization of Epicoccum nigrum antigen (allergenic antigen) or goat anti-rabbit IgG onto the photoactivated plates was found to occur in only 45 min with higher binding than that obtained through adsorption during the same period onto the untreated surface. Nearly 1.5-2-folds higher readings were obtained when the ELISA was carried out with the solid phase prepared on the photoactivated surface rather than on the untreated surface. Moreover, solid phases prepared on the activated surface could detect IgE (E. nigrum antibody) even at 1/50 (v/v) dilutions, whereas a solid phase prepared on the untreated surface failed to do so. Around three times higher ELISA values were obtained in the activated plate than the untreated plate when IgE was diluted to 1/5 (v/v). Such photoactivated surface could be of great importance in diagnostic tests involving the ELISA technique particularly to confirm false negative cases and for other immunoassays such as radioimmunoassay procedures.
- Published
- 2002
- Full Text
- View/download PDF
95. Regioselective bromination of organic substrates by tetrabutylammonium bromide promoted by V2O5-H2O2: an environmentally favorable synthetic protocol
- Author
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Bora U, Bose G, Chaudhuri MK, Dhar SS, Gopinath R, Khan AT, and Patel BK
- Abstract
[reaction: see text] Vanadium pentoxide very effectively promotes the bromination of organic substrates, including selective bromination of some aromatics, by tetrabutylammonium bromide in the presence of hydrogen peroxide; mild conditions, high selectivity, yield, and reaction rate, and redundancy of bromine and hydrobromic acid are some of the major advantages of the synthetic protocol.
- Published
- 2000
- Full Text
- View/download PDF
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