Niranjan Das - Academia.edu (original) (raw)

Papers by Niranjan Das

A pot culture experiment was conducted to assess the efficacy of certain bioagents on management ... more A pot culture experiment was conducted to assess the efficacy of certain bioagents on management of plant parasitic nematodes infecting bittergourd. Bittergourd seeds of var. Green long were sown in infested soil in 15cm diameter earthen pots. The pre-incubated bioagents viz. Purpureocillium lilacinum, Pochonia chlamydosporia, Bacillus pumilus and Pseudomonas fluorescens either alone or in combination; FYM and carbofuran were applied to the pot soil as per treatments. Need based irrigation, weeding and other cultural operations were provided. The effect of treatments on growth parameters of bittergourd plants and population of nematodes were observed 45 days after sowing and application of bioagents. It was revealed that combined application of Purpureocillium lilacinum and Pseudomonas fluorescens enhanced the vine length, root length, shoot weight and root weight of bittergourd plants to the tune of 73.3%, 62.5%, 58.0% and 82.3% respectively over untreated control. Population build...

Annals of Plant Protection Sciences, 2016

Carbon dioxide, a Greenhouse Gas (GHG), is the one of the principle pollutant, warming earth. Eno... more Carbon dioxide, a Greenhouse Gas (GHG), is the one of the principle pollutant, warming earth. Enough carbon dioxide have pumped into the earth atmosphere raising its level to 400 ppm in the past 150 years because of anthropogenic activities, higher than they have been for hundreds of thousands of years. A number of CO2 capture technologies and storage technologies are being considered to tackle this climate change. The techniques to reduce the effects of Carbon di oxide are classified as chemical reaction based strategy (abiotic) and biological mitigation method (biotic). Abiotic method captures CO2 by reaction with chemical compounds before it is released into the atmosphere. But, the disadvantages of this method are that the chemical reactions are highly energy intensive and costly; and the problematic disposal of the wasted chemical compounds. On the other hand, biological mitigation is more favorable as it directly converts CO2 into biomass. Because of photosynthetic ability of ...

Annals of Plant Protection Sciences, 2016

Integrated Disease Management module of cercospora leaf spot of groundnut was adopted by 66% farm... more Integrated Disease Management module of cercospora leaf spot of groundnut was adopted by 66% farmers and 35% adoption rate was with module for pigeon pea wilt. The module for groundnut leaf spot was found to spread maximum (272 ha) followed by the module for wilt management of sunflower (120 ha). The IDM module for management of wilting in pigeon pea and downy mildew in cucumber were observed to be less appreciated by the farmers over the time. Among the biological constraints, non-availability of quality input and seeds came to fore front followed by delayed availability. Non-availability of skilled labourers was found to be the main technological constraint. High cost of labour was the major socio-economic impediment followed by lack of appropriate credit facility for less adoption of modules.

Acta Pharmaceutica Sinica B, 2021

The phytoecdysteroids (PEs) comprise a large group of biologically-active plant steroids, which h... more The phytoecdysteroids (PEs) comprise a large group of biologically-active plant steroids, which have structures similar to those of insect-molting hormones. PEs are distributed in plants as secondary metabolites that offer protection against phytophagus (plant-eating) insects. When insects consume the plants containing these chemicals, they promptly molt and undergo metabolic destruction; the insects eventually die. Chemically, ecdysteroids are a group of polyhydroxylated ketosteroids that are structurally similar to androgens. The carbon skeleton of ecdysteroids is termed as cyclopentanoperhydro-phenanthrene with a β-side chain at carbon-17. The essential characteristics of ecdysteroids are a cis-(5β-H) junction of rings A and B, a 7-en-6-one chromophore, and a trans-(14α-OH) junction of rings C and D. Plants only synthesize PEs from mevalonic acid in the mevalonate pathway of the plant cell using acetyl-CoA as a precursor; the most common PE is 20-hydroxyecdysone. So far, over 400 PEs have been identified and reported, and a compilation of 166 PEs originating from 1998 has been previously reviewed. In the present review, we have summarized 212 new PEs reported between 1999 and 2019. We have also critically analyzed the biological, pharmacological, and medicinal properties of PEs to understand the full impact of these phytoconstituents in health and disease.

Medicines, 2020

Background:Cocculus hirsutus (L.) W.Theob. (Menispermaceae) is a perennial climber distributed mo... more Background:Cocculus hirsutus (L.) W.Theob. (Menispermaceae) is a perennial climber distributed mostly in tropical and subtropical areas. The main aim of this article is to collect and analyze the scientific information related to traditional uses, bioactive chemical constituents and pharmacological activities. Methods: Scientific information on C. hirsutus was retrieved from the online bibliographic databases (e.g. MEDLINE/PubMed, SciFinder, Web of Science, Google Scholar and Scopus). Information regarding traditional uses was also acquired from secondary resources including books and proceedings. Results: Different plant parts of C. hirsutus were reported to be used for the treatment of fever, skin diseases, stomach disorders and urinary diseases. Alkaloids such as jasminitine, hirsutine, cohirsitine and their derivatives along with a few flavonoids, triterpene derivatives and volatile compounds were reported from whole plant or different plant parts. Extracts were evaluated for th...

Plant Genetic Resources: Characterization and Utilization, 2020

Wheat, a major food crop, faces significant yield constraints due to losses caused by various dis... more Wheat, a major food crop, faces significant yield constraints due to losses caused by various diseases, especially rusts and powdery mildew. Since the causal organisms are always evolving, there is a never-ending hunt for new genes/quantitative trait loci (QTLs) for resistance to control the damage. For this purpose, Triticum durum–Aegilops speltoides backcross introgression lines (DS-BILs) developed in our wide hybridization programme were screened against stripe rust and powdery mildew at both seedling and adult plant stages. DS-BILs showed complete to moderate resistance at the adult plant stage while varying resistance and susceptibility at the seedling stage. A total of 1095 single-nucleotide polymorphisms (SNPs) identified on 14 chromosomes of T. durum, using genotyping by sequencing, were used for QTL mapping. Eleven unique QTLs, across six chromosomes (chr1B, chr2A, chr2B, chr3B, chr6B and chr7B) were identified for resistance, four QTLs for field mixture of stripe rust path...

Steroids, Jan 11, 2018

Ichnocarpus frutescens, a climber plant, is distributed all over India. As its different parts ar... more Ichnocarpus frutescens, a climber plant, is distributed all over India. As its different parts are used as anti-inflammatory agent, so we re-investigated the roots to isolate compounds and evaluate its biological efficacy. Also, in-silico molecular docking was carried out to elucidate the structure activity relationship (SAR) of isolated compounds toward identifies the drug target enzyme with validation, which was further supported by anti-inflammatory in-vitro and in-vivo experimental models. The compounds have been undertaken mainly to investigate the anti-inflammatory and analgesic efficacy along with molecular docking investigation followed by anti-proteinase, anti-denaturation and cyclo-oxygenase (COX) inhibition studies. Inflammatory cytokines like TNF-α and IL-6 were assayed from lipopolysaccharides (LPS) and Concavallin (CON A) stimulated human PBMC derived macrophages by Enyme linked immune sorbent assay (ELISA) method. The purity index of the lead compound was determined b...

Journal of the Taiwan Institute of Chemical Engineers, 2017

Food industries discharge a large quantity of waste water effluent containing a variety of water-... more Food industries discharge a large quantity of waste water effluent containing a variety of water-soluble carbohydrates which differ with regard to structural moiety and molecular mass. These carbohydrates, although non-toxic could serve as nutrients for the growth of many harmful microorganisms that cause various diseases of humans and aquatic life forms. Therefore, the soluble sugars need to be removed from the waste water prior to disposal to the environment. This research demonstrates the comparative photodegradation kinetics of monosaccharide, disaccharide, and polysaccharides by bare and Ag-TiO 2 depending upon their molecular weight and glycosidic linkages under UV irradiation. It revealed that Ag loading onto TiO 2 notably improved the photo-oxidation rates of sugar molecules to different hydroxylated intermediate photoproducts that ultimately decomposed to CO 2. Plausible degradation kinetics and mechanistic pathways for complete photomineralization of these sugars to CO 2 are briefly illustrated here by measuring optical rotation using polarimeter along with HPLC, GC and LC-MS analyses.

Beilstein journal of nanotechnology, 2017

The biophysical properties of DNA-modified Au nanoparticles (AuNPs) have attracted a great deal o... more The biophysical properties of DNA-modified Au nanoparticles (AuNPs) have attracted a great deal of research interest for various applications in biosensing. AuNPs have strong binding capability to the phosphate and sugar groups in DNA, rendering unique physicochemical properties for detection of metal ions. The formation of Au-DNA nanocomposites is evident from the observed changes in the optical absorption, plasmon band, zeta potential, DLS particle size distribution, as well as TEM and AFM surface morphology analysis. Circular dichroism studies also revealed that DNA-functionalized AuNP binding caused a conformational change in the DNA structure. Due to the size and shape dependent plasmonic interactions of AuNPs (33-78 nm) with DNA, the resultant Au-DNA nanocomposites (NCs) exhibit superior fluorescence emission due to chemical binding with Ca(2+), Fe(2+) and Mg(2+) ions. A significant increase in fluorescence emission (λex = 260 nm) of Au-DNA NCs was observed after selectively b...

Pharmaceutical biology, 2017

Visceral leishmaniasis is a protozoan disease caused by Leishmania donovani parasite. The genus S... more Visceral leishmaniasis is a protozoan disease caused by Leishmania donovani parasite. The genus Sterculia (Malvaceae) possesses ethnobotanical potential against this protozoan infection. Determining the potential role of methanol bark extracts from Sterculia villosa Roxb (SVE) and its phytoconstituents against Leishmania donovani promastigotes. SVE was analysed by TLC, UV-Vis, IR spectroscopy and biochemical assays. Antileishmanial potential of SVE (0.5-130 μg/mL for 72 h) was characterized by MTT assay. Fluorescent microscopy was performed to validate the IC50 dose. To determine the effect of SVE on promastigotes, reactive oxygen species (ROS) and superoxide generation, lipid peroxidation and DNA fragmentation assays were performed. Molecular aggregation of compounds was determined by atomic force microscopy (AFM). Extent of cytotoxicity of SVE at IC50 dose was determined against RAW 264.7 macrophages, peritoneal macrophages and murine RBCs. In vivo cytotoxicity of SVE was evaluate...

Chemistry of Natural Compounds, 2016

Continuation of the series of studies on the chemical components of the aerial parts of Sida glut... more Continuation of the series of studies on the chemical components of the aerial parts of Sida glutinosa has resulted in the isolation and characterization of a new fatty acid ester, named pentyl-10,12-dimethyl-11hydroxyoleate (1). The structure of compound 1 was established on the basis of extensive spectroscopic analysis, including two dimensional (2D) NMR. Compound 1 possessed moderate fungistatic activity (inhibition zone diameter of 12 mm) against Fusarium oxysporum at a concentration of 100 Pg after 24 h.

Indian Journal of Nematology, 2013

Indo American Journal of Pharmaceutical Research, 2013

Article history Solanum indicum Linn. (Solanaceae) is grown in waste places, road sides and in op... more Article history Solanum indicum Linn. (Solanaceae) is grown in waste places, road sides and in open scrublands in different parts of India and other Asian countries. Its roots and leaves are used in traditional system of medicine for a long time. Several phytochemicals like fatty acids, alkaloids, steroids, flavonoids and saponins have been reported from the different parts of the plant but their biological efficacies were not evaluated. Hence, the berries of the plants were collected, authenticated and extracted with MeOH for screening antioxidant and also anthelmintic activity. In vitro DPPH radical scavenging activity using BHT as a standard and anthelmintic activity on Indian earth-worm (Pheretima posthuma) using Albendazole as a standard of crude MeOH extract of Solanum indicum berries were evaluated. Nine different concentrations (200, 100, 80, 60, 40, 20, 10, 1, 0.5 µg/ml) of MeOH extract were studied for DPPH scavenging activity. The maximum DPPH radical scavenging activity with inhibition was found at the concentration 200 µg/ml and it was 70.007 ± 0.841% as comparable to that of BHT having 95.023 ± 0.091% inhibition at the same concentration. Three concentrations (25, 50, 100 mg/ml) of extract were studied for anthelmintic activity which involved the determination of time of paralysis and time of death of the worms. All the concentration of extracts exhibited significant dose dependent activity.

Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism, 1995

We report a direct observation of the microscopic origin of the bipolar resistive switching behav... more We report a direct observation of the microscopic origin of the bipolar resistive switching behavior in nanoscale titanium oxide films. Through a high-resolution transmission electron microscopy, an analytical TEM technique using energy-filtering transmission electron microscopy and an in situ x-ray photoelectron spectroscopy, we demonstrated that the oxygen ions piled up at top interface by an oxidation-reduction reaction between the titanium oxide layer and the top Al metal electrode. We also found that the drift of oxygen ions during the on/off switching induced the bipolar resistive switching in the titanium oxide thin films.

MATEC Web of Conferences, 2014

It is well established that Re and Ru additions to Ni-base superalloys result in improved creep p... more It is well established that Re and Ru additions to Ni-base superalloys result in improved creep performance and phase stability. However, the role of Re and Ru and their synergetic effects are not well understood, and the first step in understanding these effects is to design alloys with controlled microstructural parameters. A computational approach was undertaken in the present work for designing model alloys with varying levels of Re and Ru. Thermodynamic and first principles calculations were employed complimentarily to design a set of alloys with varying Re and Ru levels, but which were constrained by constant microstructural parameters, i.e., phase fractions and lattice misfit across the alloys. Three ternary/quaternary alloys of type Ni-Al-xRe-yRu were thus designed. These compositions were subsequently cast, homogenized and aged. Experimental results suggest that while the measured volume fraction matches the predicted value in the Ru containing alloy, volume fraction is significantly higher than the designed value in the Re containing alloys. This is possibly due to errors in the thermodynamic database used to predict phase fraction and composition. These errors are also reflected in the mismatch between predicted and measured values of misfit.

Acta Physiologiae Plantarum, 2014

Sucrose-phosphate synthase (SPS, EC 2.4.1.14) refers to a key enzyme in sucrose biosynthesis in b... more Sucrose-phosphate synthase (SPS, EC 2.4.1.14) refers to a key enzyme in sucrose biosynthesis in both photosynthetic and nonphotosynthetic tissues of plants. It is encoded by different gene families. SPS exists in multiple forms which show differential distributions and functional specializations in the plant tissues. SPS activity is highly regulated by hierarchy of mechanisms including transcriptional control. Here, we report an isolation of a cDNA clone (3,591 bp) encoding full-length SPS A form consisting of 1,054 amino acids (designated KC-SPS1) from a commercially important Indian potato (Solanum tuberosum L.) cultivar, Kufri Chipsona-1 by RT-PCR approach from tuber total RNA. KC-SPS1 shared 99 % sequence identity with 1,053-amino acid SPS from potato cv. Desiree. Apart from some prominent amino acid substitutions, one extra Met residue at position 235 made KC-SPS1 a distinct member of SPS A family in potato. Full-length SPS sequences from taxonomically different plant species were used in making a phylogenetic tree which showed both evolutionary relatedness, and also their grouping into different SPS families. Hydropathy characters and secondary structures were predicted in various SPS forms. Sequence analyses and comparison of the SPS sequences from the Solanaceae family members revealed many distinct features within and between the SPS gene families which were not documented earlier. SPS A form-specific expression patterns were studied in the leaves and tubers of different potato cultivars based on semi-quantitative RT-PCR and protein blot analyses. SPS activities particularly in the cold-stored tubers were probably due to altered kinetic properties. This report would be useful for in-depth studies on various SPS isoforms in potato and other Solanaceae family members.

Materials Science and Engineering: A, 2006

A study was carried out to assess the effect on mechanical and structural properties of a nickel ... more A study was carried out to assess the effect on mechanical and structural properties of a nickel based superalloy (CM247LC) upon addition of excess quantities of silicon, manganese, iron and tin added it at various concentrations and also to see the maximum extent to which they can be tolerated. Chemical and structural characterisation were carried out by using glow discharge quadrupole mass spectrometry (GD-QMS), scanning electron microscopy (SEM) and electron probe micro analysis (EPMA) techniques. Recovery of the elements Si, Mn, Fe, and Sn was found to be 7, 40, 55, and 15%, respectively. Variations of the concentrations of these elements from top to bottom of the cast were also studied. The transverse and longitudinal microstructures of nominal and doped alloys were investigated. The mechanical properties such as tensile, stress rupture strengths, ductility, and rupture life were tested at aero-engine operating conditions. The effects of the dopants on the microstructure as well as on the mechanical properties of the alloy are summarised.

A pot culture experiment was conducted to assess the efficacy of certain bioagents on management ... more A pot culture experiment was conducted to assess the efficacy of certain bioagents on management of plant parasitic nematodes infecting bittergourd. Bittergourd seeds of var. Green long were sown in infested soil in 15cm diameter earthen pots. The pre-incubated bioagents viz. Purpureocillium lilacinum, Pochonia chlamydosporia, Bacillus pumilus and Pseudomonas fluorescens either alone or in combination; FYM and carbofuran were applied to the pot soil as per treatments. Need based irrigation, weeding and other cultural operations were provided. The effect of treatments on growth parameters of bittergourd plants and population of nematodes were observed 45 days after sowing and application of bioagents. It was revealed that combined application of Purpureocillium lilacinum and Pseudomonas fluorescens enhanced the vine length, root length, shoot weight and root weight of bittergourd plants to the tune of 73.3%, 62.5%, 58.0% and 82.3% respectively over untreated control. Population build...

Annals of Plant Protection Sciences, 2016

Carbon dioxide, a Greenhouse Gas (GHG), is the one of the principle pollutant, warming earth. Eno... more Carbon dioxide, a Greenhouse Gas (GHG), is the one of the principle pollutant, warming earth. Enough carbon dioxide have pumped into the earth atmosphere raising its level to 400 ppm in the past 150 years because of anthropogenic activities, higher than they have been for hundreds of thousands of years. A number of CO2 capture technologies and storage technologies are being considered to tackle this climate change. The techniques to reduce the effects of Carbon di oxide are classified as chemical reaction based strategy (abiotic) and biological mitigation method (biotic). Abiotic method captures CO2 by reaction with chemical compounds before it is released into the atmosphere. But, the disadvantages of this method are that the chemical reactions are highly energy intensive and costly; and the problematic disposal of the wasted chemical compounds. On the other hand, biological mitigation is more favorable as it directly converts CO2 into biomass. Because of photosynthetic ability of ...

Annals of Plant Protection Sciences, 2016

Integrated Disease Management module of cercospora leaf spot of groundnut was adopted by 66% farm... more Integrated Disease Management module of cercospora leaf spot of groundnut was adopted by 66% farmers and 35% adoption rate was with module for pigeon pea wilt. The module for groundnut leaf spot was found to spread maximum (272 ha) followed by the module for wilt management of sunflower (120 ha). The IDM module for management of wilting in pigeon pea and downy mildew in cucumber were observed to be less appreciated by the farmers over the time. Among the biological constraints, non-availability of quality input and seeds came to fore front followed by delayed availability. Non-availability of skilled labourers was found to be the main technological constraint. High cost of labour was the major socio-economic impediment followed by lack of appropriate credit facility for less adoption of modules.

Acta Pharmaceutica Sinica B, 2021

The phytoecdysteroids (PEs) comprise a large group of biologically-active plant steroids, which h... more The phytoecdysteroids (PEs) comprise a large group of biologically-active plant steroids, which have structures similar to those of insect-molting hormones. PEs are distributed in plants as secondary metabolites that offer protection against phytophagus (plant-eating) insects. When insects consume the plants containing these chemicals, they promptly molt and undergo metabolic destruction; the insects eventually die. Chemically, ecdysteroids are a group of polyhydroxylated ketosteroids that are structurally similar to androgens. The carbon skeleton of ecdysteroids is termed as cyclopentanoperhydro-phenanthrene with a β-side chain at carbon-17. The essential characteristics of ecdysteroids are a cis-(5β-H) junction of rings A and B, a 7-en-6-one chromophore, and a trans-(14α-OH) junction of rings C and D. Plants only synthesize PEs from mevalonic acid in the mevalonate pathway of the plant cell using acetyl-CoA as a precursor; the most common PE is 20-hydroxyecdysone. So far, over 400 PEs have been identified and reported, and a compilation of 166 PEs originating from 1998 has been previously reviewed. In the present review, we have summarized 212 new PEs reported between 1999 and 2019. We have also critically analyzed the biological, pharmacological, and medicinal properties of PEs to understand the full impact of these phytoconstituents in health and disease.

Medicines, 2020

Background:Cocculus hirsutus (L.) W.Theob. (Menispermaceae) is a perennial climber distributed mo... more Background:Cocculus hirsutus (L.) W.Theob. (Menispermaceae) is a perennial climber distributed mostly in tropical and subtropical areas. The main aim of this article is to collect and analyze the scientific information related to traditional uses, bioactive chemical constituents and pharmacological activities. Methods: Scientific information on C. hirsutus was retrieved from the online bibliographic databases (e.g. MEDLINE/PubMed, SciFinder, Web of Science, Google Scholar and Scopus). Information regarding traditional uses was also acquired from secondary resources including books and proceedings. Results: Different plant parts of C. hirsutus were reported to be used for the treatment of fever, skin diseases, stomach disorders and urinary diseases. Alkaloids such as jasminitine, hirsutine, cohirsitine and their derivatives along with a few flavonoids, triterpene derivatives and volatile compounds were reported from whole plant or different plant parts. Extracts were evaluated for th...

Plant Genetic Resources: Characterization and Utilization, 2020

Wheat, a major food crop, faces significant yield constraints due to losses caused by various dis... more Wheat, a major food crop, faces significant yield constraints due to losses caused by various diseases, especially rusts and powdery mildew. Since the causal organisms are always evolving, there is a never-ending hunt for new genes/quantitative trait loci (QTLs) for resistance to control the damage. For this purpose, Triticum durum–Aegilops speltoides backcross introgression lines (DS-BILs) developed in our wide hybridization programme were screened against stripe rust and powdery mildew at both seedling and adult plant stages. DS-BILs showed complete to moderate resistance at the adult plant stage while varying resistance and susceptibility at the seedling stage. A total of 1095 single-nucleotide polymorphisms (SNPs) identified on 14 chromosomes of T. durum, using genotyping by sequencing, were used for QTL mapping. Eleven unique QTLs, across six chromosomes (chr1B, chr2A, chr2B, chr3B, chr6B and chr7B) were identified for resistance, four QTLs for field mixture of stripe rust path...

Steroids, Jan 11, 2018

Ichnocarpus frutescens, a climber plant, is distributed all over India. As its different parts ar... more Ichnocarpus frutescens, a climber plant, is distributed all over India. As its different parts are used as anti-inflammatory agent, so we re-investigated the roots to isolate compounds and evaluate its biological efficacy. Also, in-silico molecular docking was carried out to elucidate the structure activity relationship (SAR) of isolated compounds toward identifies the drug target enzyme with validation, which was further supported by anti-inflammatory in-vitro and in-vivo experimental models. The compounds have been undertaken mainly to investigate the anti-inflammatory and analgesic efficacy along with molecular docking investigation followed by anti-proteinase, anti-denaturation and cyclo-oxygenase (COX) inhibition studies. Inflammatory cytokines like TNF-α and IL-6 were assayed from lipopolysaccharides (LPS) and Concavallin (CON A) stimulated human PBMC derived macrophages by Enyme linked immune sorbent assay (ELISA) method. The purity index of the lead compound was determined b...

Journal of the Taiwan Institute of Chemical Engineers, 2017

Food industries discharge a large quantity of waste water effluent containing a variety of water-... more Food industries discharge a large quantity of waste water effluent containing a variety of water-soluble carbohydrates which differ with regard to structural moiety and molecular mass. These carbohydrates, although non-toxic could serve as nutrients for the growth of many harmful microorganisms that cause various diseases of humans and aquatic life forms. Therefore, the soluble sugars need to be removed from the waste water prior to disposal to the environment. This research demonstrates the comparative photodegradation kinetics of monosaccharide, disaccharide, and polysaccharides by bare and Ag-TiO 2 depending upon their molecular weight and glycosidic linkages under UV irradiation. It revealed that Ag loading onto TiO 2 notably improved the photo-oxidation rates of sugar molecules to different hydroxylated intermediate photoproducts that ultimately decomposed to CO 2. Plausible degradation kinetics and mechanistic pathways for complete photomineralization of these sugars to CO 2 are briefly illustrated here by measuring optical rotation using polarimeter along with HPLC, GC and LC-MS analyses.

Beilstein journal of nanotechnology, 2017

The biophysical properties of DNA-modified Au nanoparticles (AuNPs) have attracted a great deal o... more The biophysical properties of DNA-modified Au nanoparticles (AuNPs) have attracted a great deal of research interest for various applications in biosensing. AuNPs have strong binding capability to the phosphate and sugar groups in DNA, rendering unique physicochemical properties for detection of metal ions. The formation of Au-DNA nanocomposites is evident from the observed changes in the optical absorption, plasmon band, zeta potential, DLS particle size distribution, as well as TEM and AFM surface morphology analysis. Circular dichroism studies also revealed that DNA-functionalized AuNP binding caused a conformational change in the DNA structure. Due to the size and shape dependent plasmonic interactions of AuNPs (33-78 nm) with DNA, the resultant Au-DNA nanocomposites (NCs) exhibit superior fluorescence emission due to chemical binding with Ca(2+), Fe(2+) and Mg(2+) ions. A significant increase in fluorescence emission (λex = 260 nm) of Au-DNA NCs was observed after selectively b...

Pharmaceutical biology, 2017

Visceral leishmaniasis is a protozoan disease caused by Leishmania donovani parasite. The genus S... more Visceral leishmaniasis is a protozoan disease caused by Leishmania donovani parasite. The genus Sterculia (Malvaceae) possesses ethnobotanical potential against this protozoan infection. Determining the potential role of methanol bark extracts from Sterculia villosa Roxb (SVE) and its phytoconstituents against Leishmania donovani promastigotes. SVE was analysed by TLC, UV-Vis, IR spectroscopy and biochemical assays. Antileishmanial potential of SVE (0.5-130 μg/mL for 72 h) was characterized by MTT assay. Fluorescent microscopy was performed to validate the IC50 dose. To determine the effect of SVE on promastigotes, reactive oxygen species (ROS) and superoxide generation, lipid peroxidation and DNA fragmentation assays were performed. Molecular aggregation of compounds was determined by atomic force microscopy (AFM). Extent of cytotoxicity of SVE at IC50 dose was determined against RAW 264.7 macrophages, peritoneal macrophages and murine RBCs. In vivo cytotoxicity of SVE was evaluate...

Chemistry of Natural Compounds, 2016

Continuation of the series of studies on the chemical components of the aerial parts of Sida glut... more Continuation of the series of studies on the chemical components of the aerial parts of Sida glutinosa has resulted in the isolation and characterization of a new fatty acid ester, named pentyl-10,12-dimethyl-11hydroxyoleate (1). The structure of compound 1 was established on the basis of extensive spectroscopic analysis, including two dimensional (2D) NMR. Compound 1 possessed moderate fungistatic activity (inhibition zone diameter of 12 mm) against Fusarium oxysporum at a concentration of 100 Pg after 24 h.

Indian Journal of Nematology, 2013

Indo American Journal of Pharmaceutical Research, 2013

Article history Solanum indicum Linn. (Solanaceae) is grown in waste places, road sides and in op... more Article history Solanum indicum Linn. (Solanaceae) is grown in waste places, road sides and in open scrublands in different parts of India and other Asian countries. Its roots and leaves are used in traditional system of medicine for a long time. Several phytochemicals like fatty acids, alkaloids, steroids, flavonoids and saponins have been reported from the different parts of the plant but their biological efficacies were not evaluated. Hence, the berries of the plants were collected, authenticated and extracted with MeOH for screening antioxidant and also anthelmintic activity. In vitro DPPH radical scavenging activity using BHT as a standard and anthelmintic activity on Indian earth-worm (Pheretima posthuma) using Albendazole as a standard of crude MeOH extract of Solanum indicum berries were evaluated. Nine different concentrations (200, 100, 80, 60, 40, 20, 10, 1, 0.5 µg/ml) of MeOH extract were studied for DPPH scavenging activity. The maximum DPPH radical scavenging activity with inhibition was found at the concentration 200 µg/ml and it was 70.007 ± 0.841% as comparable to that of BHT having 95.023 ± 0.091% inhibition at the same concentration. Three concentrations (25, 50, 100 mg/ml) of extract were studied for anthelmintic activity which involved the determination of time of paralysis and time of death of the worms. All the concentration of extracts exhibited significant dose dependent activity.

Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism, 1995

We report a direct observation of the microscopic origin of the bipolar resistive switching behav... more We report a direct observation of the microscopic origin of the bipolar resistive switching behavior in nanoscale titanium oxide films. Through a high-resolution transmission electron microscopy, an analytical TEM technique using energy-filtering transmission electron microscopy and an in situ x-ray photoelectron spectroscopy, we demonstrated that the oxygen ions piled up at top interface by an oxidation-reduction reaction between the titanium oxide layer and the top Al metal electrode. We also found that the drift of oxygen ions during the on/off switching induced the bipolar resistive switching in the titanium oxide thin films.

MATEC Web of Conferences, 2014

It is well established that Re and Ru additions to Ni-base superalloys result in improved creep p... more It is well established that Re and Ru additions to Ni-base superalloys result in improved creep performance and phase stability. However, the role of Re and Ru and their synergetic effects are not well understood, and the first step in understanding these effects is to design alloys with controlled microstructural parameters. A computational approach was undertaken in the present work for designing model alloys with varying levels of Re and Ru. Thermodynamic and first principles calculations were employed complimentarily to design a set of alloys with varying Re and Ru levels, but which were constrained by constant microstructural parameters, i.e., phase fractions and lattice misfit across the alloys. Three ternary/quaternary alloys of type Ni-Al-xRe-yRu were thus designed. These compositions were subsequently cast, homogenized and aged. Experimental results suggest that while the measured volume fraction matches the predicted value in the Ru containing alloy, volume fraction is significantly higher than the designed value in the Re containing alloys. This is possibly due to errors in the thermodynamic database used to predict phase fraction and composition. These errors are also reflected in the mismatch between predicted and measured values of misfit.

Acta Physiologiae Plantarum, 2014

Sucrose-phosphate synthase (SPS, EC 2.4.1.14) refers to a key enzyme in sucrose biosynthesis in b... more Sucrose-phosphate synthase (SPS, EC 2.4.1.14) refers to a key enzyme in sucrose biosynthesis in both photosynthetic and nonphotosynthetic tissues of plants. It is encoded by different gene families. SPS exists in multiple forms which show differential distributions and functional specializations in the plant tissues. SPS activity is highly regulated by hierarchy of mechanisms including transcriptional control. Here, we report an isolation of a cDNA clone (3,591 bp) encoding full-length SPS A form consisting of 1,054 amino acids (designated KC-SPS1) from a commercially important Indian potato (Solanum tuberosum L.) cultivar, Kufri Chipsona-1 by RT-PCR approach from tuber total RNA. KC-SPS1 shared 99 % sequence identity with 1,053-amino acid SPS from potato cv. Desiree. Apart from some prominent amino acid substitutions, one extra Met residue at position 235 made KC-SPS1 a distinct member of SPS A family in potato. Full-length SPS sequences from taxonomically different plant species were used in making a phylogenetic tree which showed both evolutionary relatedness, and also their grouping into different SPS families. Hydropathy characters and secondary structures were predicted in various SPS forms. Sequence analyses and comparison of the SPS sequences from the Solanaceae family members revealed many distinct features within and between the SPS gene families which were not documented earlier. SPS A form-specific expression patterns were studied in the leaves and tubers of different potato cultivars based on semi-quantitative RT-PCR and protein blot analyses. SPS activities particularly in the cold-stored tubers were probably due to altered kinetic properties. This report would be useful for in-depth studies on various SPS isoforms in potato and other Solanaceae family members.

Materials Science and Engineering: A, 2006

A study was carried out to assess the effect on mechanical and structural properties of a nickel ... more A study was carried out to assess the effect on mechanical and structural properties of a nickel based superalloy (CM247LC) upon addition of excess quantities of silicon, manganese, iron and tin added it at various concentrations and also to see the maximum extent to which they can be tolerated. Chemical and structural characterisation were carried out by using glow discharge quadrupole mass spectrometry (GD-QMS), scanning electron microscopy (SEM) and electron probe micro analysis (EPMA) techniques. Recovery of the elements Si, Mn, Fe, and Sn was found to be 7, 40, 55, and 15%, respectively. Variations of the concentrations of these elements from top to bottom of the cast were also studied. The transverse and longitudinal microstructures of nominal and doped alloys were investigated. The mechanical properties such as tensile, stress rupture strengths, ductility, and rupture life were tested at aero-engine operating conditions. The effects of the dopants on the microstructure as well as on the mechanical properties of the alloy are summarised.