Navegando por Autor "Muniyappa, Mohan Kumar"
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Item Computational identification and evolutionary relationships of the MicroRNA gene cluster miR-71/2 in protostomes.(2013) Gomes, Matheus de Souza; Donoghue, Mark T. A.; Muniyappa, Mohan Kumar; Pereira, Roberta Verciano; Cota, Renata Guerra de Sá; Spillane, CharlesMicroRNAs (miRNAs) are small noncoding RNA molecules which are processed into *20–24 nt molecules that can regulate the gene expression posttranscriptionally. MiRNA gene clusters have been identified in a range of species, where in miRNAs are often processed from polycistronic transcripts. In this study, a computational approach is used to investigate the extent of evolutionary conservation of the miR-71/2 cluster in animals, and to identify novel miRNAs in the miRNA cluster miR-71/2. The miR-71/2 cluster, consisting of copies of the miR-71 and miR-2 (including miR-13) families, was found to be Protostome-specific. Although, this cluster is highly conserved across the Protostomia, the miR-2 family is completely absent from the Deuterostomia species, while miR-71 is absent from the Vertebrata and Urochordata. The evolutionary conservation and clustering propensity of the miR-71/2 family across the Protostomes could indicate the common functional roles across the member species of the Protostomia.Item Effect of constituents from samaras of Austroplenckia populnea (Celastraceae) on human cancer cells.(2014) Caneschi, Carolina Milagres; Muniyappa, Mohan Kumar; Duarte, Lucienir Pains; Silva, Grácia Divina de Fátima; Santos, Orlando David Henrique dos; Spillane, Charles; Vieira Filho, Sidney AugustoBackground: Aiming the continuity of the studies of Austroplenckia populnea, Brazilian species of the Celastraceae family, in the present study, it was investigated the effect of crude extracts obtained with ethanol, ethyl acetate and chloroform and two purified constituents, proanthocyanidin A and 4’-O-methylepigallocatechin, both isolated from its samaras, on cancer cell proliferation assays. Materials and Methods: The human cancer cells lines MCF-7 (ductal breast carcinoma), A549 (lung cancer), HS578T (ductal breast carcinoma) and non-cancer HEK293 (embryonic kidney cells) were treated with different concentrations of extracts and constituents and the effect was observed through the acid phosphatase method. The chemical structures of the purified compounds were identified by the respective IR and 1H and 13C nuclear magnetic resonance spectral data. Results: While crude extracts from samaras of the folk medicine A. populnea can trigger cell proliferative effects in human cell lines, the purified compounds (proanthocyanidin A and 4’-O-methyl-epigallocatechin) isolated from the same extracts can have an opposite (anti-proliferative) effect. Conclusion: Based on the results, it was possible to suggest that extracts from samaras of A. populnea should be further investigated for possible cancer-promoting activities; and the active extracts can also represent a source of compounds that have anti-cancer properties.Item Genome-wide identification of novel microRNAs and their target genes in the human parasite Schistosoma mansoni.(2011) Gomes, Matheus de Souza; Muniyappa, Mohan Kumar; Carvalho, Sávio Gonçalves; Cota, Renata Guerra de Sá; Spillane, CharlesMature microRNAs (miRNAs) are small, non-coding regulatory RNAs which can elicit post-transcriptional repression of mRNA levels of target genes. Here, we report the identification of 67 mature and 42 precursor miRNAs in the Schistosoma mansoni parasite. The evolutionarily conserved S. mansoni miRNAs consisted of 26 precursor miRNAs and 35 mature miRNAs, while we identified 16 precursor miRNAs and 32 mature miRNAs that displayed no conservation. These S. mansoni miRNAs are located on seven autosomal chromosomes and a sex (W) chromosome. miRNA expansion through gene duplication was suggested for at least two miRNA families miR-71 and mir-2. miRNA target finding analysis identified 389 predicted mRNA targets for the identified miRNAs and suggests that the sma-mir-71 may be involved in female sexual maturation. Given the important roles of miRNAs in animals, the identification and characterization of miRNAs in S. mansoni will facilitate novel approaches towards prevention and treatment of Schistosomiasis.