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Dive into the research topics where Shweta Singh is active.

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Featured researches published by Shweta Singh.


Euphytica | 2006

Genotypic variability in vegetable amaranth (Amaranthus tricolor L for foliage yield and its contributing traits over successive cuttings and years

Sudhir Shukla; Atul Bhargava; Avijeet Chatterjee; A. Srivastava; Shweta Singh

SummaryTwenty nine strains of vegetable amaranth (Amaranthus tricolor were grown for two successive seasons to study different selection parameters for foliage yield and its nine contributing morphological and quality traits. The strains AV-38 (5.06 kg/plot) and AV-31 (5.04 kg/plot) recorded highest foliage yield, followed by AV-30 (4.78 kg/plot) and AV-23 (4.70 kg/plot). The protein and carotenoid content averaged 1.24 ± 0.03 mg/100 mg and 0.83 ± 0.02 mg/g respectively. The leaves of A. tricolor also have considerable quantities of ascorbic acid (112.33 ± 5.00 mg/100 g) and fibre (8.39 ± 0.10%). The mean of individual cuttings for plant height, leaf size, stem diameter, foliage yield, protein, ascorbic acid and fibre content increased with successive cuttings till third cutting and thereafter showed a decline. Genotypic coefficient of variation (GCV) values ranged from 6.80 to 28.25%. However, the fibre content, branches/plant, leaves/plant, plant height and stem diameter showed lowest values of GCV. The values of heritability estimates were high for all the traits in all the cuttings as well as on pooled basis and ranged from 0.89 for branches/plant to 0.98 for foliage yield. Highest expected genetic advance was noticed for ascorbic acid (57.48%), followed by foliage yield (48.30%) and leaf size (29.51%).


Plant Cell Tissue and Organ Culture | 2013

Optimization of regeneration and Agrobacterium-mediated transformation of immature cotyledons of chickpea (Cicer arietinum L.)

Leena Tripathi; Aditya K. Singh; Shweta Singh; R.S. Singh; Sonam Chaudhary; Indraneel Sanyal; D. V. Amla

Immature cotyledons collected at different time intervals from four genotypes of chickpea (C 235, BG 256, P 362 and P 372) were cultured adaxially on Murashige and Skoog (MS) medium supplemented with 6-benzyladenine, thidiazuron, kinetin, zeatin and dimethylallylaminopurine (2-iP), either alone or in combination with indole-3-acetic acid (IAA) or α-napthoxyacetic acid (α-NOA) for dedifferentiation and regeneration of adventitious shoots. Morphogenesis was achieved with explants cultured adaxially on MS medium with 13.68xa0μM zeatin, 24.6xa0μM 2-iP, 0.29xa0μM IAA and 0.27xa0μM α-NOA. Explants prepared from pods of 21xa0days after pollination, responded favourably to plant growth regulator treatment in shoot differentiation. Histological studies of the regenerating explants, revealed the initiation of meristematic activity in the sub-epidermal region during the onset of morphogenesis, which can be correlated with elevated activity of cytokinin oxidase-dehydrogenase, for cytokinin metabolism. The regenerated shoots were efficiently rooted in MS medium supplemented with 2.46xa0μM indole-3-butyric acid and acclimatized under culture room and glasshouse conditions for normal plant development leading to 76–80xa0% survival of the rooted plantlets. The immature cotyledon explants were used for Agrobacterium-mediated transformation with critical manipulation of cultural conditions like age of explant, O.D. of Agrobacterium suspension, concentration of acetosyringone, duration of sonication and co-cultivation for successful genetic transformation and expression of the reporter gene uidA (GUS). Integration of transgene was confirmed by molecular analysis. Transformation frequency up to 2.08xa0% was achieved in chickpea, suggesting the feasibility of using immature cotyledon explants for Agrobacterium-mediated transformation.


Pharmacognosy Research | 2010

Antimicrobial screening of ethnobotanically important stem bark of medicinal plants

Meenakshi Singh; Sayyada Khatoon; Shweta Singh; Vivek Kumar; Ajay Kumar Singh Rawat; Shanta Mehrotra

Background: The stem barks are the rich sources of tannins and other phenolic compounds. Tannins inhibited the growth of various fungi, yeast, bacteria and virus. Hence, ten stem barks of ethnomedicinally important plants were screened for antibacterial and antifungal activities against human pathogenic strains. Methods: Air-dried and powdered stem bark of each plant was extracted with 50% aqueous ethanol, lyophilized and the dried crude extracts were used for the screening against 11 bacteria and 8 fungi. Antibacterial and antifungal activities were performed according to microdilution methods by NCCLS. Results: The plants Prosopis chilensis, Pithecellobium dulce, Mangifera indica showed significant antibacterial and antifungal activities against Streptococcus pneumonia, Enterobacter aerogenes, Klebsiella pneumonia and Candida albicans with MIC of 0.08mg/ml. Pithecellobium dulce bark also showed significant antibacterial activity against Bacillus cereus. Conclusion: The bark of Pithecellobium dulce has more or less similar activity against the known antibiotic and may be considered as potent antimicrobial agent for various infectious diseases.


Pharmaceutical Biology | 2011

Antibacterial activity of some bryophytes used traditionally for the treatment of burn infections

Meenakshi Singh; Shweta Singh; Virendra Nath; Vinay Sahu; Ajay Kumar Singh Rawat

Context: Plagiochasma appendiculatum L. & L. (Aytoniaceae), Conocephalum conicum (L.) Necker (Conocephalaceae), Bryum argenteum Hedw. (Bryaceae), and Mnium marginatum (With.) P. Beauv. (Mniaceae) are bryophytes (liverworts and mosses) used by traditional healers for the treatment of burn, cuts, wounds, and skin disorders. Objective: This study evaluated the antibacterial activity of four bryophytes against some common bacteria responsible for burn infections. Materials and methods: Different fractions of bryophytes were screened using the disc diffusion (qualitative) and broth microdilution (quantitative) methods, according to the guidelines of the National Committee for Clinical and Laboratory Standards. Results and discussion: Chloroform fractions of liverworts were more active against Gram negative strains while butanol fractions of mosses had significant activity against Gram positive bacteria. Staphylococcus aureus was the most sensitive strain of those tested with the butanol fraction of M. marginatum (moss), with the strongest inhibition zone of 102.92% and minimum inhibitory concentration of 30u2009μg mL−1. Conclusion: Our findings support the use of the bryophytes in traditional medicine for burn infections because of their significant antibacterial activity.


Genetic Resources and Crop Evolution | 2006

Alkaloid Spectrum of Different Germplasm Lines in Opium Poppy (Papaver somniferum L.)

Sudhir Shukla; Shweta Singh; Hemant Kumar Yadav; Avijeet Chatterjee

The opium latex of 1470 individual plant samples of 98 germplasm lines were screened for five major economic alkaloids. The alkaloids profile showed that morphine content ranged from 9.20–20.86% with an average of 15.00xa0±xa00.267. Codeine ranged from 1.69–6.48% with arithmetic mean of 3.35xa0±xa00.091, thebaine from 0.52–7.95% with an average of 2.27xa0±xa00.116. Narcotine ranged from 8.79–17.97% with an average 8.79xa0±xa00.266 and papaverine content ranged from 0.00–6.07% with an average 1.18xa0±xa00.167 in over all the germplasm lines. The content of different alkaloids categorized into class interval which exhibited that maximum number of plants and accessions for morphine content fall in group of 10–15% followed by 15–20%, for codeine content in group of 2–4% followed by 4–6%, for thebaine content in 1–2% followed by 2–4%, for narcotine in 5–10% followed by 10–15% and for papaverine content 0–2%. 24 germplasm lines had morphine content above 16.0%. Similarly, 37 germplasm lines for codeine and 13 for thebaine showed consistently high content, i.e., above 3%. 33 germplasm lines had narcotine content above 9% and 20 lines exhibited papaverine content above 2%. Line BR 316 was found unique having thebaine content 6.27–9.33%. The probable reasons of increase or decrease of different alkaloids based on their biosynthetic pathway has been discussed in detail.


RSC Advances | 2015

Development and characterization of a novel Swarna-based herbo-metallic colloidal nano-formulation – inhibitor of Streptococcus mutans quorum sensing

Brahma N. Singh; Prateeksha; Garima Pandey; Vishwjeet Jadaun; Shweta Singh; Rajesh Bajpai; Sanjeeva Nayaka; Alim H. Naqvi; Ajay Kumar Singh Rawat; D. K. Upreti; Braj Raj Singh

Herbo-metallic preparations such as bhasmas (ash) are used traditionally in Indian and Chinese medicinal systems. In Ayurveda, Swarna (gold) nanoparticles are used as Swarna bhasma to treat several clinical manifestations. While Usnea longissima, a medicinal lichen, ethnobotanical is known for the treatment of tooth cleaning and infectious diseases. The study aims to develop a herbo-metallic colloidal nano-formulation containing Swarna nanoparticles and polyphenols rich U. longissima extract (ULE) and evaluate its anti-quorum sensing (QS) property against Streptococcus mutans, an idea that has never been explored before, with a view towards combating the emergence of antibiotic resistance often linked with QS-regulated virulence factors and biofilms. The synthesized Uh-Au@Nano-CF was confirmed by a peak at 550 nm in the UV-visible spectrum. The obtained XRD data confirmed the crystalline nature of nanoparticles of 28 nm size. TEM image revealed that all the particles were spherical with a narrow size range of 5–23 nm. The FTIR result clearly showed that the ULE containing secondary OH as functional groups induces encapsulation of nanoparticles. HPTLC and HPLC fingerprinting of ULE confirmed the presence of polyphenols, including orcinol, arabitol, apigenin, and usnic acid. The data from the inhibition of violacein production in C. violaceum 12u2006472 revealed that the Uh-Au@Nano-CF at sub-lethal concentrations (5, 10 and 15%) show potent anti-QS activity. The treatment of Uh-Au@Nano-CF was found to inhibit the secretion of S. mutans virulence factors, including acid production, ATPase, enolase, lactate dehydrogenase, protease, total exopolysaccharide content, and glucosidase. The Uh-Au@Nano-CF in a concentration dependent manner showed anti-biofilm activity, inhibiting biofilm formation. Eventually, it was also documented that the Uh-Au@Nano-CF at 15% dilution enhanced the susceptibility of S. mutans to its conventional antibiotics. This study introduces not only a novel antimicrobial herbo-metallic colloidal nano-formulation, but also explores its new biomedical application, which targets QS-regulated virulence factors and biofilm of S. mutans rather than its viability.


Journal of the Science of Food and Agriculture | 1998

Variation of major fatty acids in F8 generation of opium poppy (Papaver somniferum × Papaversetigerum) genotypes

Shweta Singh; Sudhir Shukla; K. R. Khanna; B. S. Dixit; R. Banerji

The fatty acid compositions in F8 genotypes of a cross between Papaver somniferum×Papaver setigerum were studied. The oil content in both species was quite variable, ie 38·0% in P setigerum and 47·8% in P somniferum, while C18 fatty acids were quite comparable. The F8 genotypes had higher oil contents (>40%) and fatty acid concentrations than the parental species. Linoleic acid ranged between 68% (BRO 54) and 74·4% (BRO 59) and oleic acid varied between 13·6% (BRO 65) and 20·3% (BRO 54). High oleic desaturation ratio (ODR, >0·79) and C18 polyunsaturated fatty acid (>87%) with very low C18: 3 (0·37±0·01) indicate the possibility of using poppy oil for the edible oil industry. Oleic (18:1) acid was not correlated with the other fatty acids, except for significant negative correlation with linoleic (C18: 2) acid.


Physiology and Molecular Biology of Plants | 2015

Assessment of genetic diversity in indigenous turmeric (Curcuma longa) germplasm from India using molecular markers

Sushma Verma; Shweta Singh; Suresh Kumar Sharma; S.K. Tewari; R. K. Roy; A. K. Goel; T. S. Rana

Curcuma longa L., commonly known as turmeric, is one of the economically and medicinally important plant species. It is predominantly cultivated in the tropical and sub tropical countries. India is the largest producer, and exporter of turmeric in the world, followed by China, Indonesia, Bangladesh and Thailand. In the present study, Directed Amplification of Minisatellite DNA (DAMD) and Inter Simple Sequence Repeats (ISSR), methods were used to estimate the genetic variability in indigenous turmeric germplasm. Cumulative data analysis for DAMD (15) and ISSR (13) markers resulted into 478 fragments, out of which 392 fragments were polymorphic, revealing 82xa0% polymorphism across the turmeric genotypes. Wide range of pairwise genetic distances (0.03–0.59) across the genotypes revealed that these genotypes are genetically quite diverse. The UPGMA dendrogram generated using cumulative data showed significant relationships amongst the genotypes. All 29 genotypes studied grouped into two clusters irrespective of their geographical affiliations with 100xa0% bootstrap value except few genotypes, suggesting considerable diversity amongst the genotypes. These results suggested that the current collection of turmeric genotypes preserve the vast majority of natural variations. The results further demonstrate the efficiency and reliability of DAMD and ISSR markers in determining the genetic diversity and relationships among the indigenous turmeric germplasm. DAMD and ISSR profiling have identified diverse turmeric genotypes, which could be further utilized in various genetic improvement programmes including conventional as well as marker assisted breeding towards development of new and desirable turmeric genotypes.


Pharmaceutical Biology | 1995

Alkaloid Spectrum of Opium of a Cross Between Papaver somniferum and P. setigerum

Sudhir Shukla; K. R. Khanna; Shweta Singh

AbstractThe F8 generation of a cross between Papaver somniferum and P. setigerum shows considerable diversity in major alkaloids, the most important of which is morphine. The range of this alkaloid exceeds that of the superior parent, P. somniferum. Therefore, selecting superior individuals and poly crossing may enhance morphine content.


Analytical Letters | 2013

Biochemical Composition of Curcuma longa L. Accessions

Abhishek Niranjan; Shweta Singh; Manjul Dhiman; Shri Krishna Tewari

The essential oil composition and total phenolic content (TPC) of curcuminoids were studied in rhizomes of nine Curcuma longa L. accessions. Curcuminoids, present in commercially available turmeric rhizomes, play vital roles in various pharmacological activities. A simple, rapid, and sensitive high performance liquid chromatography photodiode array (HPLC-PDA) method was optimized for simultaneous determination of curcuminoids, namely, a mixture of curcumin, demethoxy curcumin (DMC), and bisdemethoxy curcumin (BDMC) in rhizomes of C. longa. Chromatographic separation was performed on an RP C18 column within 13 minutes (11.4 to 12.95 minutes). Elution was accomplished by the application of acetonitrile and 1.5% acetic acid in water in a gradient system with flow rate of 2.0 mL min−1. PDA was employed for qualitative and quantitative analysis. The calibration curves were found linear (0.99) for all cucuminoids; the limit of detection and quantification ranged between 1.01 µ g mL−1 to 1.16 µ g mL−1 and 2.30 µ g mL−1 to 3.05 µ g mL−1, respectively, while recovery values ranged between 97.97% to 98.32%. The amount of curcumin varied from 0.46% to 2.17%, DMC from 0.13% to 0.92% and BDMC from 0.06% to 0.52%. The validated method was successively used to determine the above compounds in C. longa rhizomes. The TPC in rhizomes ranged from 14.12 mg g−1 to 27.72 mg g−1. The chemical composition of rhizome essential oil, analyzed by gas chromatography mass spectrometry (GCMS,) showed large variations in major compounds like ar-tumerone (7.31–38.66%), β-curcumene (1.58–24.53%), and curlone (1.55–15.97%).

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Sudhir Shukla

National Botanical Research Institute

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Suresh Kumar Sharma

National Botanical Research Institute

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R. Banerji

National Botanical Research Institute

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Ajay Kumar Singh Rawat

National Botanical Research Institute

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Avijeet Chatterjee

National Botanical Research Institute

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K. R. Khanna

National Botanical Research Institute

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Abhishek Niranjan

Council of Scientific and Industrial Research

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Atul Bhargava

National Botanical Research Institute

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Bs Dixit

National Botanical Research Institute

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S.K. Tewari

National Botanical Research Institute

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