Base de dados : LILACS
Pesquisa : G05.728.615.200 [Categoria DeCS]
Referências encontradas : 11 [refinar]
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  1 / 11 LILACS  
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Id: lil-640991
Autor: Stoll, L. B; Cremonesi, F. C. A; Pires, L. T. A; Zucchi, T. D; Zucchi, T. M. A. D.
Título: Induction of mitotic crossing-over in diploid strains of Aspergillus nidulansusing low-dose X-rays
Fonte: Genet. mol. res. (Online);7(2):467-475, 2008.
Idioma: en.
Projeto: CNPq; . FAPESP.
Resumo: As a contribution towards detecting the genetic effects of low doses of genotoxic physical agents, this paper deals with the consequences of low-dose X-rays in the Aspergillus nidulans genome. The irradiation doses studied were those commonly used in dental clinics (1-5 cGy). Even very low doses promoted increased mitotic crossing-over frequencies in diploid strains heterozygous for several genetic markers including the ones involved in DNA repair and recombination mechanisms. Genetic markers of several heterozygous strains were individually analyzed disclosing that some markers were especially sensitive to the treatments. These markers should be chosen as bio-indicators in the homozygotization index assay to better detect the recombinogenic/carcinogenic genomic effects of low-dose X-rays.
Descritores: Aspergillus nidulans/efeitos da radiação
Mitose/efeitos da radiação
Troca Genética/efeitos da radiação
Raios X
-Aspergillus nidulans/genética
Diploide
Dano ao DNA
Homozigoto
Testes de Mutagenicidade
Mitose/genética
Relação Dose-Resposta à Radiação
Troca Genética/genética
Responsável: BR26.1 - Biblioteca Central


  2 / 11 LILACS  
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Texto completo SciELO Brasil
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Id: lil-486873
Autor: Melo, Sandra P; Gómez, Vanessa; Castellanos, Isabel C; Alvarado, Magda E; Hernández, Paula C; Gallego, Amanda; Wasserman, Moisés.
Título: Transcription of meiotic-like-pathway genes in Giardia intestinalis
Fonte: Mem. Inst. Oswaldo Cruz;103(4):347-350, June 2008. graf, tab.
Idioma: en.
Projeto: Colciencias; . Univ Nac de Colombia. Inst Nac de Salud.
Resumo: The reproductive mechanism of Giardia intestinalis, considered one of the earliest divergent eukaryotes, has not been fully defined yet. Some evidence supports the hypothesis that Giardia is an exclusively asexual organism with a clonal population structure. However, the high genetic variability, the variation in ploidy during its life cycle, the low heterozygosity and the existence of genes involved in the meiotic-like recombination pathway in the parasite's genome cast doubt on exclusively asexual nature of Giardia. In this work, semiquantitative RT-PCR analysis was used to assess the transcription pattern of three meiosis-like-specific genes involved in homologues recombination: dmc1, hop1 and spo11. The mRNAs were amplified during the parasite's differentiation processes, encystation and excystation, and expression was found at each stage of its life cycle. A semiquantitative assessment also suggests that expression of some of the genes is regulated during encystation process.
Descritores: Genes de Protozoários/genética
Giardia lamblia/genética
Meiose/genética
-Troca Genética
Reprodução Assexuada
Reação em Cadeia da Polimerase Via Transcriptase Reversa
RNA Mensageiro
Transcrição Genética
Limites: Animais
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  3 / 11 LILACS  
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Id: lil-456759
Autor: Ricci, G. L; Silva, N; Pagliarini, M. S; Scapim, C. A.
Título: B chromosomes in popcorn (Zea mays L. )
Fonte: Genet. mol. res. (Online);6(1):137-143, 2007. tab, ilus.
Idioma: en.
Resumo: Cytological analysis of microsporogenesis in 72 popcorn plants, comprising nine from the original population (CMS-43, S0) and 63 from seven cycles of self-fertilization (S1 to S7), one plant of S0 generation (plant 2) was identified with B chromosomes. The number of B chromosomes varied from two to three in the same anther. The pattern of chromosome pairing and meiotic behavior of Bs were similar to those found in other plant species. The presence of B chromosomes did not affect chiasma frequency and chiasma distribution in A chromosomes. This is the first report of B chromosomes in popcorn
Descritores: Cromossomos de Plantas/genética
Troca Genética/genética
Genoma de Planta/genética
Meiose/genética
Zea mays/genética
-Zea mays/citologia
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  4 / 11 LILACS  
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Texto completo SciELO Chile
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Id: lil-456609
Autor: Souza-Junior, S. A; Becker, T. C. A; Castro-Prado, M. A. A.
Título: Asexual Recombination in a uvsH Mutant of Aspergillus nidulans
Fonte: Biol. Res;40(1):65-71, 2007. ilus, tab, graf.
Idioma: en.
Resumo: Mutations in the gene uvsH of Aspergillus nidulans result in increased spontaneous chromosome instability and increased intragenic and intergenic mitotic recombination in homozygous diploids. The aim of the present work was to obtain a uvs mutant of A. nidulans and to use it for the isolation of asexual recombinants (parameiotic segregants). The mutant uvsH, named B511, showed normal frequency of meiotic recombination in sexual crosses and high frequency of parameiotic segregants in the parasexual crossings with master strains (B511//A757 and B511//A288). Asexual haploid recombinants (parameiotic segregants), diploid and aneuploid segregants were recovered directly from the uvs//uvs+ heterokaryons (B511//A757 and B511// A288). Parameiotic segregants originated through mitotic crossing-over and independent assortment of chromosomes.
Descritores: Aspergillus nidulans/genética
Troca Genética
Genes Fúngicos/genética
Mutação/genética
Reprodução Assexuada/genética
-Aspergillus nidulans/fisiologia
Haploidia
Meiose/genética
Meiose/fisiologia
Mitose/genética
Mitose/fisiologia
Reprodução Assexuada/fisiologia
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  5 / 11 LILACS  
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Texto completo SciELO Brasil
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Id: lil-355266
Autor: Busso, Cleverson; Castro-Prado, Marialba A. A.
Título: Cremophor EL stimulates mitotic recombination in uvsH//uvsH diploid strain of Aspergillus nidulans
Fonte: An. acad. bras. ciênc;76(1):49-55, Mar. 2004. tab.
Idioma: en.
Resumo: Cremophor EL is a solubilizer and emulsifier agent used in the pharmaceutical and foodstuff industries. The solvent is the principal constituent of paclitaxel's clinical formulation vehicle. Since mitotic recombination plays a crucial role in multistep carcinogenesis, the study of the recombinagenic potential of chemical compounds is of the utmost importance. In our research genotoxicity of cremophor EL has been studied by using an uvsH//uvsH diploid strain of Aspergillus nidulans. Since it spends a great part of its cell cycle in the G2period, this fungus is a special screening system for the study of mitotic recombination induced by chemical substances. Homozygotization Indexes (HI) for paba and bi markers from heterozygous B211//A837 diploid strain were determined for the evaluation of the recombinagenic effect of cremophor EL. It has been shown that cremophor EL induces increase in mitotic crossing-over events at nontoxic concentrations (0.05 and 0.075 percent v/v).
Descritores: Aspergillus nidulans
Troca Genética
Tensoativos
-Ácido 4-Aminobenzoico
Aspergillus nidulans
Diploide
Mitose
Testes de Mutagenicidade
Responsável: BR1.1 - BIREME


  6 / 11 LILACS  
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Texto completo SciELO Chile
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Id: lil-309735
Autor: Chiuchetta, Simone Jurema Ruggeri; Castro-Prado, Marialba Avezum Alves de.
Título: Vincristine induces somatic segregation, via mitotic crossing-over, in diploid cells of Aspergillus nidulans
Fonte: Biol. Res;35(1):31-38, 2002. ilus, tab, graf.
Idioma: en.
Resumo: Vincristine is an alkaloid widely used as an antineoplastic agent. In eukaryotic cells the drug causes blockage in the G2 phase of the cell cycle and an increase in the frequency of sister chromatid exchanges. Due to the fact that germinating Aspergillus nidulans cells spend most of their cycle in G2 phase, they provide an excellent system for the study of mitotic crossing-over. Taking into account that mitotic crossing-over occurs during G2 period, the evaluation of recombinagenic and aneugenic potential of vincristine is provided with regard to two diploid strains of A. nidulans: a wild strain (uvsH+//uvsH+) and a defective one in DNA repair (uvsH//uvsH). Drug toxicity and its effect on the asexual cycle of A. nidulans has been evaluated as well. Treatment of both strains with vincristine did not change colony growth in the culture, however cytological analyses showed aberrant conidiophores. Recombinagenic potential of vincristine was evaluated by induction of gene homozygosis originally present in heterozygosity diploid strains (Homozygotization Index). Results show that vincristine induces mitotic crossing-over and higher frequency of aneuploid mitotic segregants. The results also show the recombinagenic and aneuploidogenic potential of vincristine and suggest its participation in the induction of secondary malignancies.
Descritores: Antineoplásicos Fitogênicos
Aspergillus nidulans
Segregação de Cromossomos
Troca Genética
Diploide
Mitose
Vincristina
-Aneuploidia
Aspergillus nidulans
Genótipo
Troca de Cromátide Irmã
Responsável: BR1.1 - BIREME


  7 / 11 LILACS  
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Id: lil-164707
Autor: Pires, Lidia Terêsa de Abreu; Zucchi, Tânia Maria Araújo Domingues.
Título: A new method to detect potential genotoxic agents using mitotic crossing-over in diploid strains of Aspergillus nidulans
Fonte: Rev. bras. genét = Braz. j. genet;17(4):371-6, dez. 1994. ilus, tab.
Idioma: en.
Projeto: FAPESP; . CNPq.
Resumo: This paper presents a new method for detecting mitotic crossing-over in Aspergillus nidulans, based on the "homozygosity index" (HI) of recessive genes originally present in hetrozygosis in diploid strains, which occurs after mitotic crossing-over between the marker in question and the centromere. Since homozygous diploids (-/-) for auxotrophic markers can not grow in MM, homozygotization can be demonstrated by distorted mitotic segregation of the alleles involved. Two similar diploid strains (UT 448/UT 184 and Z1//UT 184), which differ by a chromosomic duplicate segment transposed from chromosome II to I in the Z1 haploid strain, were used. This excess of genetic material confers to the Z1 mutant the uvs character and makes Z1//UT 184 more unstable and sensitive to genotoxic agents, as evidenced by its high spontaneous recombinational index.
Descritores: Alelos
Aspergillus nidulans/genética
Troca Genética/efeitos da radiação
Diploide
Homozigoto
Mitose
Mutação
Raios Ultravioleta/efeitos adversos
-Aspergillus nidulans/citologia
Responsável: BR1.1 - BIREME


  8 / 11 LILACS  
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Id: lil-139583
Autor: Pavan, J; Gualandi, Francesca; Rimessi, Paola; Corallini, A; Barbanti-Brodano, G.
Título: Genes oncosupresores: nuevas perspectivas para la investigación clínica en cáncer / Tumor suppressor genes: new perspectives for clinical investigations in cancer
Fonte: Medicina (B.Aires);54(2):163-8, 1994. tab.
Idioma: es.
Resumo: La tumorigénesis comprende una serie de eventos genéticos específicos que ocurren en una célula y en sus descendientes clonales. El desarrollo de la biologia molecular durante la última década, permitió distribuir estos eventos dentro de dos categorías: la activación de protooncogenes y la inactivación de genes oncosupresores. Los genes oncosupresores son genes cuya inactivación es requerida para la transformación maligna de una célula. La pérdida de los genes oncosupresores juega un importante papel en el desarrollo de los tumores humanos. Estudios en hibridos celulares somáticos han demonstrado que la supresión tumorigénica ocurre en las células neoplásicas que reciben cromosomas humanos normales mediante fusión celular. Estos experimentos han demostrado que la tumorigénesis es un carácter fenotipicamente recessivo, controlado por cromosomas específicos. Ciertos tipos de genes oncosupresores, p. ej. p53 y RB1, están implicados en una gran variedad de neoplasias, mientras otros, p. ej., el gen DCC, están restingidos a un solo tipo de tumores. La detección de mutaciones germinales en los genes oncosupresores permitirá la identificación de los individuos con alto riesgo de desarrollar neoplasias
Descritores: Troca Genética/fisiologia
Genes Supressores de Tumor/fisiologia
Neoplasias/genética
Oncogenes
-Genes do Retinoblastoma
Genes do Tumor de Wilms
Supressão Genética
Transformação Celular Neoplásica/genética
Responsável: BR1.1 - BIREME


  9 / 11 LILACS  
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Id: lil-134347
Autor: Martín, Rodolfo S.
Título: Biología molecular del riñón poliquístico / The molecular biology of the polycystic kidney
Fonte: Medicina (B.Aires);52(4):355-62, jul.-ago. 1992. ilus.
Idioma: es.
Descritores: Rim Policístico Autossômico Dominante/genética
-Southern Blotting
Clonagem Molecular
Troca Genética
DNA/genética
Rim Policístico Autossômico Dominante/diagnóstico
Rim Policístico Autossômico Dominante/patologia
Hibridização de Ácido Nucleico
Análise de Sequência
Limites: Humanos
Responsável: BR1.1 - BIREME


  10 / 11 LILACS  
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Id: lil-100773
Autor: Glieb García-Quintana, Hector.
Título: Microorganismos:poderosa herramienta en el avance de la Genética Molecular / Microorganisms: useful tools for the advancement of molecular
Fonte: Adelantos microbiol. enfermedades infecc;(8):1-17, oct. 1990. ilus.
Idioma: es.
Descritores: Genética Microbiana
-Bacteriófagos/genética
Conjugação Genética
Cruzamentos Genéticos
Troca Genética
Genes Bacterianos
Genes Virais
Lisogenia
Mutação
Recombinação Genética
Transdução Genética
Tipo de Publ: Revisão
Responsável: AR144.1 - CIBCHACO - Centro de Información Biomedica del Chaco



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