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Search Results: 1 - 10 of 76109 matches for " Maria Helena Pelegrinelli; "
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An overview on molecular markers for detection of ochratoxigenic fungi in coffee neans
Fungaro, Maria Helena Pelegrinelli;Sartori, Daniele;
Brazilian Archives of Biology and Technology , 2009, DOI: 10.1590/S1516-89132009000700001
Abstract: ochratoxin a (ota) is one of the most abundant food-contaminating mycotoxins. its occurrence in several agricultural commodities has been considered a worldwide problem. this toxin is mainly produced by aspergillus species. ota has nephrotoxic, immunosuppressive, and carcinogenic effects and consequently the contamination with this toxin represents a high risk for human and animal health. in the last 5 years, several investigators have applied molecular methods in order to develop pcr assays for identifying and quantifying ota-producing fungi in coffee beans samples. the main objective is to allow the detection of microorganisms capable of producing ota, preferentially prior to ochratoxin production and accumulation. in this contribution several of these attempts will be reviewed and discussed.
Transgênicos e evolu??o dirigida
Azevedo, Jo?o Lúcio de;Fungaro, Maria Helena Pelegrinelli;Vieira, Maria Lúcia Carneiro;
História, Ciências, Saúde-Manguinhos , 2000, DOI: 10.1590/S0104-59702000000300014
Abstract: mutation events are responsible for the generation of genetic variability in the populations enabling the occurrence of natural selection which favors the better-adapted types. the exploitation of this variability, though carried out empirically, dates from ten thousand years ago with the domestication of the first cultivated crops. with the advent of genetics, rational selection procedures were adopted with a view to the genetic breeding of plants, animals and microorganisms which might be of interest to men. recently, new dna manipulation techniques came up enabling the transference of genes between organisms, cutting across barriers which hindered crossings between the vegetable, animal, protist and fungus kingdoms. the generation of genetically modified organisms, or transgenics, has aroused a heated and controversial debate in various sectors of our society. yet we must be cautious before generalizing the use of transgenics since each one should be analyzed at a time for its particular advantages and drawbacks, and for its contribution to the improvement of life quality. this paper also considers recent methods of mutation and in vitro genic recombination.
Genetic instability of sugarcane plants derived from meristem cultures
Zucchi Maria Imaculada,Arizono Hideto,Morais Vicente Alberto,Fungaro Maria Helena Pelegrinelli
Genetics and Molecular Biology , 2002,
Abstract: The RADP (Random amplified polymorphic DNA) technique was used to detect tissue-culture-induced variations in sugarcane. Plants of the Brazilian variety RB83-5486 propagated via rhizomes and via meristem cultures were studied. The polymorphism rate for 98 RAPD loci was 6.93% when the plants derived from meristems. Besides, in order to evaluate the influence of the number of subcultures on the generation of somaclonal variation, field-grown RB83-5486 plants derived from 10 meristems were studied after five subcultivations. Although different rates of polymorphism were observed, there was no direct association with the stage of subcultivation. The analysis of plants of two sugarcane varieties cultivated in vitro from meristems showed that variety RB83-5486 was more unstable than variety SP80-185.
Transgênicos e evolu o dirigida
Azevedo Jo?o Lúcio de,Fungaro Maria Helena Pelegrinelli,Vieira Maria Lúcia Carneiro
História, Ciências, Saúde-Manguinhos , 2000,
Abstract: Os eventos de muta o s o responsáveis pela gera o de variabilidade genética nas popula es, permitindo a a o da sele o natural que favorece os tipos mais adaptados. A explora o dessa variabilidade, embora de forma empírica, teve início há cerca de dez mil anos, quando se deu a domestica o das primeiras culturas agrícolas. Com o advento da genética, práticas racionais de sele o passaram a ser adotadas visando o melhoramento genético de plantas, animais e microrganismos de interesse para o homem. Recentemente, surgiram as técnicas de manipula o de DNA, permitindo a transferência de genes entre organismos, transpondo barreiras de cruzamento entre os reinos vegetal, animal, protista e fungi. A gera o dos organismos geneticamente modificados, ou transgênicos, tem sido alvo de polêmica e discuss o nos diversos segmentos da sociedade. Porém, n o se deve generalizar o uso dos transgênicos, pois cada um deve ser analisado quanto às suas vantagens, desvantagens e contribui o à melhoria da qualidade de vida. Métodos recentes de muta o e recombina o gênica in vitro s o também apresentados no texto.
Fusarium verticillioides strains isolated from corn feed: characterization by fumonisin production and RAPD fingerprinting
Ono, Elisabete Yurie Sataque;Fungaro, Maria Helena Pelegrinelli;Sofia, Silvia Helena;Miguel, Tatiana de ávila;Sugiura, Yoshitsugu;Hirooka, Elisa Yoko;
Brazilian Archives of Biology and Technology , 2010, DOI: 10.1590/S1516-89132010000400026
Abstract: in this study a total of 16 fusarium verticillioides strains isolated from corn feed samples were characterized by fumonisin (fb) production and random amplified polymorphic dna (rapd). all the strains produced fb1 and fb2 with levels ranging from 2.41 to 3996.36 μg/g, and from 1.18 to 1209.91 μg/g, respectively. from the 16 f. verticillioides strains, four were identified as low (3.59 to 1289.84 μg/g), eight as intermediate (>1289.84 to 3772.44 μg/g) and four strains as high (>3772.44 μg/g) fumonisin producers. from the total of 105 loci amplified, 60 (57.14%) were polymorphic. rapd analysis showed very similar patterns among low, moderate and high fumonisin-producing strains. although rapd markers were capable of discriminating the different f. verticillioides strains, there was no clear association between these makers and fumonisin production.
Genetic instability of sugarcane plants derived from meristem cultures
Zucchi, Maria Imaculada;Arizono, Hideto;Morais, Vicente Alberto;Fungaro, Maria Helena Pelegrinelli;Vieira, Maria Lúcia Carneiro;
Genetics and Molecular Biology , 2002, DOI: 10.1590/S1415-47572002000100017
Abstract: the radp (random amplified polymorphic dna) technique was used to detect tissue-culture-induced variations in sugarcane. plants of the brazilian variety rb83-5486 propagated via rhizomes and via meristem cultures were studied. the polymorphism rate for 98 rapd loci was 6.93% when the plants derived from meristems. besides, in order to evaluate the influence of the number of subcultures on the generation of somaclonal variation, field-grown rb83-5486 plants derived from 10 meristems were studied after five subcultivations. although different rates of polymorphism were observed, there was no direct association with the stage of subcultivation. the analysis of plants of two sugarcane varieties cultivated in vitro from meristems showed that variety rb83-5486 was more unstable than variety sp80-185.
Genetic variation in the cuticle-degrading protease activity of the entomopathogen Metarhizium flavoviride
Pinto Fabiana Gisele da Silva,Fungaro Maria Helena Pelegrinelli,Ferreira Josué Maldonado,Valadares-Inglis Maria Cléria
Genetics and Molecular Biology , 2002,
Abstract: Extracellular proteases have been shown to be factors of virulence in fungal entomopathogenicity. We examined the production of the cuticle-degrading extracellular proteases chymoelastase (Pr1) and trypsin (Pr2) in isolates of the fungus Metarhizium flavoviride. Fungal growth was in a mineral medium (MM) containing nitrate, and in MM supplemented with either cuticle from Rhammatocerus schistocercoides or with the non-cuticular substrate casein. The substrates used for growth influenced the expression of both analyzed proteases, the highest protease activities of nearly all isolates having been observed in the medium containing insect cuticle, with more Pr1 than Pr2 being produced. There was a natural variability in the production of cuticle-degrading proteases among isolates, although this was less evident for Pr2. Our data support the hypothesis that the production of Pr1 on insect cuticle is a useful characteristic for the analysis of intraspecific variability of M. flavoviride isolates.
Effects of double-stranded RNA on virulence of Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) against the silverleaf whitefly, Bemisia tabaci strain B (Homoptera: Aleyrodidae)
Azevedo, Andréia Cristiane Souza;Sosa-Gómez, Daniel Ricardo;Faria, Marcos Rodrigues;Fungaro, Maria Helena Pelegrinelli;
Genetics and Molecular Biology , 2000, DOI: 10.1590/S1415-47572000000100010
Abstract: bands of double-stranded rna (dsrna) were detected in three out of twelve isolates of paecilomyces fumosoroseus. identity of these bands was confirmed by rnase, dnase and s1 nuclease treatments. the cure of dsrna for one isolate (p92) was successfully carried out for a single conidium subculture. isogenic strains, with or without dsrna, were submitted to virulence tests against the whitefly bemisia tabaci strain b. in contrast to findings for some phytopathogenic fungi, these dsrna fragments did not cause hypovirulence in p. fumosoroseus.
Molecular characterization of Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) isolates
Azevedo, Andréia Cristiane Souza;Furlaneto, Márcia Cristina;Sosa-Gómez, Daniel Ricardo;Fungaro, Maria Helena Pelegrinelli;
Scientia Agricola , 2000, DOI: 10.1590/S0103-90162000000400021
Abstract: its and rapd analyses were used to investigate molecular variations within samples of paecilomyces isolates and to resolve five morphologically atypical isolates resembling p. fumosorosus, obtained from whitefly in northern paraná state. the its4-its5 amplicon was 700 base pairs (bp) long in all isolates. the five isolates of paecilomyces not assigned to species produced restriction profiles identical to all the reference strains of p. fumosoroseus. the extent of fingerprint variability observed by rapd was sufficient to discriminate all the isolates. the genetic similarity among unidentified isolates and strains of p. fumosoroseus was even higher than that observed among reference strains of this species, allowing us to conclude that isolates cnpso-p77, cnpso-p78, cnpso-p80, cnpso-p85 and cnpso-p91 are p. fumosoroseus.
Effects of double-stranded RNA on virulence of Paecilomyces fumosoroseus (Deuteromycotina: Hyphomycetes) against the silverleaf whitefly, Bemisia tabaci strain B (Homoptera: Aleyrodidae)
Azevedo Andréia Cristiane Souza,Sosa-Gómez Daniel Ricardo,Faria Marcos Rodrigues,Fungaro Maria Helena Pelegrinelli
Genetics and Molecular Biology , 2000,
Abstract: Bands of double-stranded RNA (dsRNA) were detected in three out of twelve isolates of Paecilomyces fumosoroseus. Identity of these bands was confirmed by RNAse, DNAse and S1 nuclease treatments. The cure of dsRNA for one isolate (P92) was successfully carried out for a single conidium subculture. Isogenic strains, with or without dsRNA, were submitted to virulence tests against the whitefly Bemisia tabaci strain B. In contrast to findings for some phytopathogenic fungi, these dsRNA fragments did not cause hypovirulence in P. fumosoroseus.
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