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Archana Sharma

Other affiliations: Laval University
Bio: Archana Sharma is an academic researcher from University of Calcutta. The author has contributed to research in topics: Sister chromatid exchange & Chromosome. The author has an hindex of 35, co-authored 234 publications receiving 5783 citations. Previous affiliations of Archana Sharma include Laval University.


Papers
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Journal ArticleDOI
TL;DR: In vivo induction of sister chromatid exchanges and micronuclei formations by acute treatment with different concentrations of sorbic acid and by nitrite gave synergistic effects which could possibly be ascribed to the formation of certain genotoxic compounds in vivo.

46 citations

Journal ArticleDOI
TL;DR: The evolution of Chromosome Structure and the Origin of Agricultural Strains in Crop Plants and its Significance in Speciation are studied.
Abstract: Introducction 514 Types of Chromosomal Change in Relation to Speciation 516 Diminution in Chromatin as an Indication of Structural Changes in Chromosomes 518 Karyotypic Changes and the Origin of Agricultural Strains in Crop Plants 520 Fragmentation of Chromosomes as a Physical Basis of Speciation 521 A Tentative Suggestion Regarding the Evolution of Chromosome Structure 524 Inconstancy in Chromosome Complements within a Tissue and its Significance in Speciation 526 Conclusion 532 Further Research 534 References 5 35

46 citations

Journal ArticleDOI
TL;DR: Higher plants used extensively in traditional medicines are increasingly being screened for their role in modulating the activity of environmental genotoxicants, and plant extracts able to modify the process of mutagenesis, which involves alteration in the genetic material are extended.
Abstract: Higher plants used extensively in traditional medicines are increasingly being screened for their role in modulating the activity of environmental genotoxicants. The property of preventing carcinogenesis has been reported in many plant extracts. The observation of a close association between carcinogenesis and mutagenesis has extended the survey to include plant extracts and plant products able to modify the process of mutagenesis, which involves alteration in the genetic material. Natural plant products may, apart from inducing mutations, modify the action of other known mutagens on the living organisms by 1) activating the existing mutagens within the cell, 2) inhibiting the production of mutagens in the cell, 3) synergising the activity of existing mutagens, or 4) activating the promutagens within the cell into mutagens. This review deals with data obtained in the course of research on the modulatory effects of plant extracts on mutagenesis and clastogenesis, two genotoxic phenomena associated with carcinogenesis.

45 citations

Journal ArticleDOI
TL;DR: In the progeny, clastogenic effects of sodium arsenite persisted in a lower degree, indicating that the metal is able to cross the transplacental barrier, and there was no statistically significant difference between the effect in progeny of parents only given salt when given simultaneously for prolonged periods in the parents.
Abstract: Mice were fed by gavage crude garlic extract (100 mg/kg b.wt.) for 30 consecutive days. One set was administered sodium arsenite (0.1 mg/kg b.wt.) simultaneously. Another set was treated with sodium arsenite only. Mice given distilled water were kept as negative control. Exposed mice from each set were sacrificed and bone marrow preparations examined for chromosomal aberrations and damaged cells. Sodium arsenite is a strong clastogen and the effects were reduced to a significant level by prolonged administration of garlic extract. For F1 studies, exposed male mice were mated with exposed female mice and the progeny examined. In the progeny, clastogenic effects of sodium arsenite persisted in a lower degree, indicating that the metal is able to cross the transplacental barrier. There was no statistically significant difference between the effects in progeny of parents only given sodium arsenite and those given both the metallic salt and garlic extract. Garlic extract is able to reduce the clastogenic effects of sodium arsenite when given simultaneously for prolonged periods in the parents; however, the effect is meagre in the next generation.

45 citations

Journal ArticleDOI
TL;DR: Dietary administration of a crude aqueous extract of Emblica officinalis Gaertn fruit reduced significantly the cytotoxic effects of sodium arsenite administered orally, bringing the cells almost to the normal level.
Abstract: Dietary administration of a crude aqueous extract of Emblica officinalis Gaertn. fruit reduced significantly the cytotoxic effects of sodium arsenite administered orally. The crude extract (685 mg/kg bw) was given daily by gavaging to age and sex matched laboratory bread Swiss albino mice for 7 and 14 days, followed by a single dose of sodium arsenite (2.5 mg/kg bw = 1/10 of LD 50 ). The animals were killed after 24 h and chromosome preparations made following a schedule of colchicine-fixative-air drying-Giemsa. The endpoints screened were chromosomal aberrations and damaged cells. The crude extract reduced arsenic damage bringing the cells almost to the normal level.

43 citations


Cited by
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Journal Article
TL;DR: Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional, and suggestions are made where such possibilities may be worth pursuing.
Abstract: Flavonoids are nearly ubiquitous in plants and are recognized as the pigments responsible for the colors of leaves, especially in autumn. They are rich in seeds, citrus fruits, olive oil, tea, and red wine. They are low molecular weight compounds composed of a three-ring structure with various substitutions. This basic structure is shared by tocopherols (vitamin E). Flavonoids can be subdivided according to the presence of an oxy group at position 4, a double bond between carbon atoms 2 and 3, or a hydroxyl group in position 3 of the C (middle) ring. These characteristics appear to also be required for best activity, especially antioxidant and antiproliferative, in the systems studied. The particular hydroxylation pattern of the B ring of the flavonoles increases their activities, especially in inhibition of mast cell secretion. Certain plants and spices containing flavonoids have been used for thousands of years in traditional Eastern medicine. In spite of the voluminous literature available, however, Western medicine has not yet used flavonoids therapeutically, even though their safety record is exceptional. Suggestions are made where such possibilities may be worth pursuing.

4,663 citations

Journal ArticleDOI
TL;DR: Flavonoids are plant pigments that are synthesised from phenylalanine, generally display marvelous colors known from flower petals, mostly emit brilliant fluorescence when they are excited by UV light, and are ubiquitous to green plant cells.

2,424 citations

Journal ArticleDOI
21 Oct 2004-Nature
TL;DR: Genome analysis provides a greatly improved fish gene catalogue, including identifying key genes previously thought to be absent in fish, and reconstructs much of the evolutionary history of ancient and recent chromosome rearrangements leading to the modern human karyotype.
Abstract: Tetraodon nigroviridis is a freshwater puffer fish with the smallest known vertebrate genome. Here, we report a draft genome sequence with long-range linkage and substantial anchoring to the 21 Tetraodon chromosomes. Genome analysis provides a greatly improved fish gene catalogue, including identifying key genes previously thought to be absent in fish. Comparison with other vertebrates and a urochordate indicates that fish proteins have diverged markedly faster than their mammalian homologues. Comparison with the human genome suggests ∼900 previously unannotated human genes. Analysis of the Tetraodon and human genomes shows that whole-genome duplication occurred in the teleost fish lineage, subsequent to its divergence from mammals. The analysis also makes it possible to infer the basic structure of the ancestral bony vertebrate genome, which was composed of 12 chromosomes, and to reconstruct much of the evolutionary history of ancient and recent chromosome rearrangements leading to the modern human karyotype.

1,889 citations

Journal ArticleDOI
TL;DR: Results obtained from available animal studies suggest that the compound is protective, and further studies are needed to better understand the cellular effects of this essential, but potentially toxic, trace mineral and its functional interaction with other nutrients.

1,722 citations

Journal ArticleDOI
24 Apr 2003-Nature
TL;DR: A high-quality draft sequence of the N. crassa genome is reported, suggesting that RIP has had a profound impact on genome evolution, greatly slowing the creation of new genes through genomic duplication and resulting in a genome with an unusually low proportion of closely related genes.
Abstract: Neurospora crassa is a central organism in the history of twentieth-century genetics, biochemistry and molecular biology. Here, we report a high-quality draft sequence of the N. crassa genome. The approximately 40-megabase genome encodes about 10,000 protein-coding genes—more than twice as many as in the fission yeast Schizosaccharomyces pombe and only about 25% fewer than in the fruitfly Drosophila melanogaster. Analysis of the gene set yields insights into unexpected aspects of Neurospora biology including the identification of genes potentially associated with red light photobiology, genes implicated in secondary metabolism, and important differences in Ca21 signalling as compared with plants and animals. Neurospora possesses the widest array of genome defence mechanisms known for any eukaryotic organism, including a process unique to fungi called repeat-induced point mutation (RIP). Genome analysis suggests that RIP has had a profound impact on genome evolution, greatly slowing the creation of new genes through genomic duplication and resulting in a genome with an unusually low proportion of closely related genes.

1,659 citations