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Registros recuperados: 31
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A two-step strategy for the complementation of M: tuberculosis mutants Genet. Mol. Biol.
Movahedzadeh,Farahnaz; Frita,Rosangela; Gutka,Hiten J..
The sequence of Mycobacterium tuberculosis, completed in 1998, facilitated both the development of genomic tools, and the creation of a number of mycobacterial mutants. These mutants have a wide range of phenotypes, from attenuated to hypervirulent strains. These phenotypes must be confirmed, to rule out possible secondary mutations that may arise during the generation of mutant strains. This may occur during the amplification of target genes or during the generation of the mutation, thus constructing a complementation strain, which expresses the wild-type copy of the gene in the mutant strain, becomes necessary. In this study we have introduced a two-step strategy to construct complementation strains using the Ag85 promoter. We have constitutively...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Tuberculosis; Mutagenesis; Constitutive expression; Complementation.
Ano: 2011 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572011000200020
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Acetaldehyde induced developmental and genetic damage in Drosophila melanogaster JBAG
Palermo,A.M; Mudry,M.D.
Acetaldehyde (AAld) is a ubiquitous compound in the environment. Exposure may occur in its manufacture or use, in the consumption of alcoholic beverages and through cigarette smoke. It causes distant target effects, including DNA damage, glutathione depletion, enzyme inactivation and cell death. In the present work, its potential teratogenic, mutagenic and recombinagenic effects in somatic cells of D. melanogaster were analyzed. The white/white+ (w/w+) eye mosaic test (Somatic Mutation And Recombination Test, SMART) was applied by mating w/w females with y/Y males. Larvae of 48 ± 4 h were transferred to media with 0.01 %, 0.02 %, 0.05 % and 0.10 % AAld for 12 hs and then moved to regular media until pupation. The emerging w/w+ females were evaluated for...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Ethanol; Teratogenesis; Mutagenesis; Loss of heterozygosity; Eye-spot test.
Ano: 2015 URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1852-62332015000300007
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Application of ecoTILLING to relate molecular variation in a rice ethylene response factor (ERF3) gene to drought stress responses International Rice Research Institute
Wang, Hehe.
xi, 86 leaves : ill. Thesis (M.S.) -- University of the Philippines at Los Baños
Tipo: Thesis Palavras-chave: Rice; Plant genetics; Genes; Ethylene; Drought tolerance; Ecotypes; Breeding methods; Mutagenesis.
Ano: 2005 URL: http://hdl.handle.net/123456789/348
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Biocontrol potential of salinity tolerant mutants of Trichoderma harzianum against Fusarium oxysporum BJM
Mohamed,Hassan Abdel-Latif A.; Haggag,Wafaa Mohamed.
Exposing a wild-type culture of Trichoderma harzianum to gamma irradiation induced two stable salt-tolerant mutants (Th50M6 and Th50M11). Under saline conditions, both mutants greatly surpassed their wild type strain in growth rate, sporulation and biological proficiency against Fusarium oxysporum, the causal agent of tomato wilt disease. Tolerant T. harzianum mutants detained a capability to grow and convinced sporulation in growth media containing up to 69 mM NaCl. In comparison with their parent strain, characterization of both mutants confirmed that they have reinforced contents of proline and hydroxyproline, relatively higher sodium content compared to potassium, calcium or magnesium contents, higher level of total phenols. Electrophoretic analysis of...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Antifungal metabolites; Mutagenesis; Gamma-irradiation; Salt stress; Trichoderma harzianum; Fusarium oxysporium.
Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822006000200016
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Bioensaios de toxicidade genética com Tradescantia. Infoteca-e
RODRIGUES, G. S..
Resumo: Dentre a variedade de bioensaios disponíveis para estudos de detecção e monitoração dos efeitos tóxicos genéticos de substâncias e ambientes contaminados, os bioensaios que empregam a planta Tradescantia destacam-se pela sensibilidade e facilidade de realização de estudos de curto prazo in situ. Este trabalho apresenta uma revisão extensiva dos estudos de mutagênese ambiental empregando Tradescantia como bioindicador, e é complementado com resultados experimentais e indicações metodológicas.
Tipo: Documentos (INFOTECA-E) Palavras-chave: Bioensaio; Toxidez; Mutação; Agrotóxico; Tradescantia; Bioassays; Mutagenesis; Genotoxicity; Pesticides.
Ano: 1999 URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/1051547
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Biological Response of Tradescantia Stamen-hairs to High Levels of Natural Radiation in the Poços de Caldas Plateau BABT
Gomes,Heliana de Azevedo; Nouailhetas,Yannick; Silva,Nivaldo Carlos da; Mezrahi,Arnaldo; Almeida,Carlos E. Bonacossa de; Rodrigues,Geraldo Stachetti.
The objective of the present study was to apply a highly sensitive botanical test of mutagenicity (the Tradescantia stamen-hair mutation bioassay) to assess in situ the biological responses induced by naturally occurring radiation in the Poços de Caldas Plateau. The mutagenesis was evaluated in environments presenting gamma radiation exposure rates ranging from 1.5 muR.min-1 up to 100.0 muR.min-1. The results consistently showed only borderline increases in mutation frequencies in plants exposed to areas with high radiation background, as compared to non-exposed plants. It was concluded that the levels of natural radiation prevalent in the Poços de Caldas Plateau were not sufficient to induce significant increases in mutation rate, even in the extremely...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Mutagenesis; Natural radiation; Bioassay; Tradescantia.
Ano: 2002 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000300008
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Chromosomal aberrations in peripheral lymphocytes from male native miners working in the Peruvian Andes Genet. Mol. Biol.
Santa Maria,Sergio R.; Arana,Margarita; Ramirez,Oswaldo.
We analyzed the frequency of chromosomal aberrations in peripheral lymphocytes from underground miners from the Casapalca (n = 8, mean age = 45 y, range = 36 y to 55 y) and Bellavista (n = 8, mean age = 28 y, range 23 y to 34 y) high-altitude mining camps in the Peruvian Andes. This population was occupationally exposed to heavy metals such as lead and zinc as well as diesel emission particles, organic solvents and mine dust. The control groups consisted of individuals from a high altitude farming community in the Peruvian village of Tinco (n = 8, mean age = 37 y, range = 25 y to 52 y) and the sea level city of Lima (n = 14, mean age = 26 y, range = 20 y to 35 y). All individuals were male native Peruvians. A significantly higher incidence (1.88%, p <...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Chromosomal aberrations; High altitude; Mutagenesis; Peruvian Andes; Underground miners.
Ano: 2007 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000600017
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Comparison of nuclear abnormalities in Astyanax bifasciatus Cuvier, 1819 (Teleostei: Characidae) of two sections of rivers from the middle Iguaçu Biological Sciences
Melo-Silva, Merieli; Oliveira, Felipe Rafael; Rosa, Jonathan; Gemelli, Emanuelli; Santos, Lilian; Bueno-Krawczyk, Ana Carolina de Deus.
Most changes in water bodies are result of human activities that have the potential to undermine the environmental integrity of aquatic ecosystems. Changes in genetic material can be evidenced by the frequency of nuclear abnormalities in fish blood cells, in response to genotoxic agents even at low concentrations. Thus, we aimed at comparing the frequencies of nuclear abnormalities of fish kept in acclimation, with fish collected in Timbó river (Santa Cruz do Timbó, Santa Catarina State), under low anthropogenic interference, and fish collected in Iguaçu river (União da Vitória, Paraná State), a polluted river. The highest frequency of changes in nuclear morphology of fish erythrocytes was found in the urbanized area around the Iguaçu river, while, the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Micronucleus; Ecotoxicology; Mutagenesis; Pollution. Mutagênese.
Ano: 2018 URL: http://periodicos.uem.br/ojs/index.php/ActaSciBiolSci/article/view/40669
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Deletion of DNA sequences of using a polymerase chain reaction based approach Electron. J. Biotechnol.
Pérez-Pinera,Pablo; Menéndez-González,Manuel; Vega,José Antonio.
We developed a simple, rapid and reliable method to delete DNA fragments in plasmids using a polymerase chain reaction based amplification of the circular DNA sequence that excludes the fragment to be deleted. The primers are designed to contain a non-complementary 5' sequence consisting of a restriction enzyme target sequence. Following PCR amplification, the plasmid is digested with Dpn I to eliminate the template DNA, with the chosen restriction enzyme, and ligated. The only limitation is the selection of the restriction enzyme target sequence that must not be present in the original plasmid. The method is straightforward in its execution and success relies on a meticulous primer design that permits us obtain 100% of transformants containing the desired...
Tipo: Journal article Palavras-chave: Deletion; Mutagenesis; Polymerase chain reaction; Plasmid.
Ano: 2006 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582006000500018
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Effects of H2O2, Fe2+ and Fe3+ on curcumin-induced chromosomal aberrations in CHO cells Genet. Mol. Biol.
Antunes,Lusânia Maria Greggi; Araújo,Maria Cristina Paiva; Dias,Francisca da Luz; Takahashi,Catarina Satie.
The effects of H2O2, Fe2+ and Fe3+ on curcumin-induced clastogenicity were evaluated in CHO cells. Curcumin combined with H2O2 did not increase the chromosomal aberrations more than expected based on a simple additive effect. In contrast, the combination of curcumin-Fe significantly decreased the total number of chromosomal aberrations and the number of abnormal metaphases. The clastogenicity of curcumin may be related to its pro-oxidant properties and its ability to generate free radicals.
Tipo: Info:eu-repo/semantics/article Palavras-chave: CHO; Chromosomal aberrations; Curcumin; Hydrogen peroxide; Mutagenesis.
Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000100028
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Elevated yield of Monacolin K in Monascus purpureus by fungal elicitor and mutagenesis of UV and LiCl Biol. Res.
Sun,Jia-Long; Zou,Xiao; Liu,Ai-Ying; Xiao,Tang-Fu.
In China, Monascus spp., a traditional fungus used in fermentation, is used as a natural food additive. Monascus spp. can produce a secondary metabolite, monacolin K namely, which is proven to be a cholesterol-lowering and hypotensive agent. Hence, recently, many researchers have begun focusing on how to increase the production of monacolin K by Monascus purpureus. In the present study, we investigated the effect of the fungal elicitor and the mutagenesis of UV &amp; LiCl on the amount of monacolin K produced by Monascus purpureus. The fugal elicitor, Sporobolomyces huaxiensis, was isolated from tea leaves and its filtrate was added into the culture filtrate of Monascus purpureus during growth to induct the production of monacolin K. The results showed...
Tipo: Journal article Palavras-chave: Monascus spp.; Monacolin K; Fungal elicitor; Mutagenesis.
Ano: 2011 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602011000400010
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Enzyme activity and thermostability of a non-specific nuclease from Yersinia enterocolitica subsp. palearctica by site-directed mutagenesis Electron. J. Biotechnol.
Zhang,Yu; Li,Zhen-Hua; Zheng,Wei; Tang,Zhen-Xing; Zhang,Zhi-Liang; Shi,Lu-E.
Background: To identify the critical amino acid residues that contribute to the high enzyme activity and good thermostability of Yersinia enterocolitica subsp. palearctica (Y. NSN), 15 mutants of Y. NSN were obtained by site-directed mutagenesis in this study. And their enzyme activity and thermostability were assayed. Effect of several factors on the enzyme activity and thermostability of Y. NSN, was also investigated. Results: The results showed that the I203F and D264E mutants retained approximately 75% and 70% enzyme activity, respectively, compared to the wild-type enzyme. In addition to the I203F and D264E mutants, the mutant E202A had an obvious influence on the thermostability of Y. NSN. According to the analysis of enzyme activity and...
Tipo: Journal article Palavras-chave: Factors affecting enzyme activity; Nuclease; Mutation; Mutagenesis; Nucleases without sequence specificity.
Ano: 2016 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582016000600005
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Genetic damage induced by trophic doses of lead in the neotropical fish Hoplias malabaricus (Characiformes, Erythrinidae) as revealed by the comet assay and chromosomal aberrations Genet. Mol. Biol.
Cestari,Marta Margarete; Lemos,Priscilla Maria M.; Ribeiro,Ciro Alberto de Oliveira; Costa,João Ricardo M. Alves; Pelletier,Emilien; Ferraro,Marcos V.M.; Mantovani,Mário Sérgio; Fenocchio,Alberto Sergio.
The effects of clastogenic or mutagenic agents have rarely been studied in neotropical fish species exposed to contaminated water. In this study, the genetic damage caused by lead in the widely distributed South American fish, Hoplias malabaricus, was assessed using the comet (SCGE) assay and by testing for chromosomal aberrations. Eighteen specimens were acclimatized to laboratory conditions and then chronically exposed to contaminated food by feeding prey (Cyprinus sp.) injected intraperitoneally with doses of inorganic lead adjusted to give a contamination level of 21 mg of Pb2+.g-1 net weight of H. malabaricus. Three fish were sampled for chromosomal analysis after four doses (18 days) and another three after eight doses (41 days) of lead and the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Chromosomal aberrations; Comet assay; Genotoxicity; Hoplias malabaricus; Lead; Mutagenesis.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000200023
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Genotoxicity and mutagenicity of Echinodorus macrophyllus (chapéu-de-couro) extracts Genet. Mol. Biol.
Vidal,Leonardo S.; Alves,Adriana M.; Kuster,Ricardo M.; Lage,Claudia; Leitão,Alvaro C..
Echinodorus macrophyllus, commonly known as chapéu-de-couro, is a medicinal plant used in folk medicine to treat inflammation and rheumatic diseases. In this work, we used short-term bacterial assays based on the induction of SOS functions to examine the genotoxicity and mutagenicity of an aqueous extract of E. macrophyllus leaves. Whole extract and an ethyl acetate fraction showed similar genotoxicity and caused an ~70-fold increase in lysogenic induction. The extract also gave a positive result in the SOS chromotest with an increase of 12-fold in β-Galactosidase enzymatic units. There was a strong trend towards base substitutions and frameshifts at purine sites in the mutations induced by the extract in Escherichia coli (CC103 and CC104 strains) and...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Echinodorus macrophyllus; Genotoxicity; Mutagenesis; Reactive oxygen species.
Ano: 2010 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000300028
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Global analysis of gene function in mammals: Integration of physical, mutational and expression strategies Electron. J. Biotechnol.
Schimenti,John.
The field of Genetics is undergoing tumultuous change after nearly a century of standard approaches to genetic analysis. The Human Genome Project is providing tools and technologies that are changing the ways that we pursue an understanding of gene function, which is the underlying goal in modern and traditional genetics. In this paper, I overview the directions of the genome project as they relate to gene function analysis in mice and humans, and how various modern technologies are coalescing to address this in a powerful way.
Tipo: Journal article Palavras-chave: Gene expression; ESTs; Mutagenesis; Genome; Functional genomics.
Ano: 1998 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000100005
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Hydrogen peroxide induces a specific DNA base change profile in the presence of the iron chelator 2,2’ dipyridyl in Escherichia coli BJMBR
Felício,D.L.; Almeida,C.E.B.; Silva,A.B.; Leitão,A.C..
Pretreatment of Escherichia coli cultures with the iron chelator 2,2’-dipyridyl (1 mM) protects against the lethal effects of low concentrations of hydrogen peroxide (<15 mM). However, at H2O2 concentrations equal to or greater than 15 mM, dipyridyl pretreatment increases lethality and mutagenesis, which is attributed to the formation of different types of DNA lesions. We show here that pretreatment with dipyridyl (1 mM) prior to challenge with high H2O2 concentrations (≥15 mM) induced mainly G:C→A:T transitions (more than 100X with 15 mM and more than 250X with 20 mM over the spontaneous mutagenesis rate) in E. coli. In contrast, high H2O2 concentrations in the absence of dipyridyl preferentially induced A:T→T:A transversions (more than 1800X and more...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Hydrogen peroxide; Dipyridyl; Mutagenesis; Iron; Fenton reaction.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2009001100003
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Improving Production of Tacrolimus In Streptomyces Tacrolimicus (ATCC 55098) Through Development of Novel Mutant by Dual Mutagenesis BABT
Singh,Bhanu P; Kumar,Punit; Haque,Shafiul; Jawed,Arshad; Dubey,Kashyap Kumar.
ABSTRACT Tacrolimus is a polyketide macrolide produced by Streptomyces species which is widely used as anti-fibrotic agent and potent immunosuppressant. In this article dual mutagenesis approach using mutagens (NTG+EMS+UV) was used to develop a mutant strain of Streptomyces tacrolimicus (ATCC 55098) for higher tacrolimus production and this strain showed higher tacrolimus production at 82.5 mg/l. Interestingly; addition of L-Lysine (0.2 g/l) into the production medium further enhanced the tacrolimus production to ~102 mg/l at 7-L fed-batch bioreactor. To the best of our knowledge this is the first report mentioning efficient strain development for higher production of tacrolimus using dual mutagenesis. The obtained data presents an impressive model for...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Immunosuppressant; Macrolide polyketide; Tacrolimus; Mutagenesis.
Ano: 2017 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132017000100419
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In situ monitoring of mutagenicity of air pollutants in São Paulo City using Tradescantia-SHM bioassay BABT
Ferreira,Maria Izildinha; Rodrigues,Geraldo Stachetti; Domingos,Marisa; Saldiva,Paulo Hilário do N..
The Tradescantia stamen hair mutation assay (Trad-SHM) was employed for assessing the environmental mutagenesis in two areas of São Paulo City. The study sites were defined as follows: 1) Celso Garcia Avenue, an industrial area on the outskirts of the urban center (Belém neighborhood), with an average daily traffic volume of 8,750 vehicles; 2) Doutor Arnaldo Avenue, in downtown area (Pinheiros neighborhood), with a mostly residential and business offices occupation, with an average daily traffic volume of 46,125 vehicles. The negative control (background) site is located in the city of Jaguariúna, 138 km from São Paulo, in an area of low atmospheric pollution. The mutation frequency observed for Belém was similar to the background for clone 4430, whereas...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Pollution; Mutagenesis; Bioassay; Tradescantia.
Ano: 2003 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132003000200017
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Inducing mutations in the mouse genome with the chemical mutagen ethylnitrosourea BJMBR
Massironi,S.M.G.; Reis,B.L.F.S.; Carneiro,J.G.; Barbosa,L.B.S.; Ariza,C.B.; Santos,G.C.; Guénet,J.L.; Godard,A.L.B..
When compared to other model organisms whose genome is sequenced, the number of mutations identified in the mouse appears extremely reduced and this situation seriously hampers our understanding of mammalian gene function(s). Another important consequence of this shortage is that a majority of human genetic diseases still await an animal model. To improve the situation, two strategies are currently used: the first makes use of embryonic stem cells, in which one can induce knockout mutations almost at will; the second consists of a genome-wide random chemical mutagenesis, followed by screening for mutant phenotypes and subsequent identification of the genetic alteration(s). Several projects are now in progress making use of one or the other of these...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Mouse; Ethylnitrosourea; Mutation; Co-isogenic mutations; Mutagenesis.
Ano: 2006 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2006000900009
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Investigation of cytotoxic and mutagenic effects of Malpighia glabra L. (barbados cherry) fruit pulp and vitamin C on plant and animal test systems Ciênc. Tecnol. Aliment.
Düsman,Elisângela; Ferreira,Márcia Flores da Silva; Berti,Alessandra Paim; Mariucci,Rosinete Gonçalves; Mantovani,Mário Sérgio; Vicentini,Veronica Elisa Pimenta.
Fruits are important sources of nutrients in human diet, and Barbados Cherry (Malpighia glabra L.) is of particular interest due to its high content of antioxidants. Diets rich in fruits and vegetables protect individuals against diseases and cancer, but excessive intake of vitamins may act as pro-oxidant and generate changes in DNA. To evaluate the effect of different in natura (BAN) and frozen (BAF) Barbados Cherry pulp concentrations and synthetic vitamin C in liquid form (VC) on the chromosome level and the cell cycle division, root meristeme cells of Allium cepa L. and bone marrow cells of Wistar rats Rattus norvegicus, were used as test system. In Allium cepa L., BAN, at the highest concentration (0.4 mg.mL-1) and BAF, at the lowest concentration...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Antioxidants; Cytotoxicity; Mutagenesis.
Ano: 2012 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612012000200030
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