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Search Results: 1 - 10 of 19876 matches for " Luciana Cordeiro;Pio-Ribeiro "
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Stock indexing and Potato virus Y elimination from potato plants cultivated in vitro
Nascimento, Luciana Cordeiro;Pio-Ribeiro, Gilvan;Willadino, Lilia;Andrade, Genira Pereira;
Scientia Agricola , 2003, DOI: 10.1590/S0103-90162003000300017
Abstract: potato cultivars (solanum tuberosum l.) have shown degeneration or run out caused by viruses after several cycles of propagation using seed tubers from commercial fields. this work reports the occurrence of single and mixed infections of four potato viruses in paraíba-brazil and presents a method for potato virus y (pvy) elimination, by using thermo-and chemotherapies. plants of potato cv. baraka were tested by direct antigen coating elisa. antisera against pvy, potato virus x (pvx), potato virus s (pvs), and potato leafroll virus (plrv) were used. materials with positive reaction to pvy were treated for virus elimination. single node cuttings (1.0 cm length) were excised and inoculated in murashige & skoog (ms) medium, supplemented with 1.0 mg l-1 of kinetin, 0.001 mg l-1 of naphthalene acetic acid (naa) and 0.1 mg l-1 of gibberellic acid (ga3). the thermotherapy at approximately 37oc, during 30 and 40 days, resulted in 20.0 and 37.5% pvy elimination, respectively. chemotherapy was undertaken with ribavirin (rbv), 5-azacytidine (aza), and 3-deazauridine (dzd). the rbv showed the highest rate of virus eradication, with 55.5% virus-free plants. simultaneous thermo and chemotherapy had higher efficiency for the elimination of pvy, reaching rates of healthy plants of 83.3% with rbv, 70.0% with aza, and 50.0% with dzd.
Stock indexing and Potato virus Y elimination from potato plants cultivated in vitro
Nascimento Luciana Cordeiro,Pio-Ribeiro Gilvan,Willadino Lilia,Andrade Genira Pereira
Scientia Agricola , 2003,
Abstract: Potato cultivars (Solanum tuberosum L.) have shown degeneration or run out caused by viruses after several cycles of propagation using seed tubers from commercial fields. This work reports the occurrence of single and mixed infections of four potato viruses in Paraíba-Brazil and presents a method for Potato virus Y (PVY) elimination, by using thermo-and chemotherapies. Plants of potato cv. Baraka were tested by direct antigen coating ELISA. Antisera against PVY, Potato virus X (PVX), Potato virus S (PVS), and Potato leafroll virus (PLRV) were used. Materials with positive reaction to PVY were treated for virus elimination. Single node cuttings (1.0 cm length) were excised and inoculated in Murashige & Skoog (MS) medium, supplemented with 1.0 mg L-1 of kinetin, 0.001 mg L-1 of naphthalene acetic acid (NAA) and 0.1 mg L-1 of gibberellic acid (GA3). The thermotherapy at approximately 37oC, during 30 and 40 days, resulted in 20.0 and 37.5% PVY elimination, respectively. Chemotherapy was undertaken with Ribavirin (RBV), 5-Azacytidine (AZA), and 3-Deazauridine (DZD). The RBV showed the highest rate of virus eradication, with 55.5% virus-free plants. Simultaneous thermo and chemotherapy had higher efficiency for the elimination of PVY, reaching rates of healthy plants of 83.3% with RBV, 70.0% with AZA, and 50.0% with DZD.
Evaluation of peanut genotypes for resistance to Tomato spotted wilt virus by mechanical and thrips inoculation
Nascimento, Luciana Cordeiro do;Pensuk, Viboon;Costa, Nivania Pereira da;Assis Filho, Francisco Miguel de;Pio-Ribeiro, Gilvan;Deom, Carl Michael;Sherwood, John;
Pesquisa Agropecuária Brasileira , 2006, DOI: 10.1590/S0100-204X2006000600006
Abstract: the objective of this work was to evaluate the reactions of three peanut breeding lines (ic-10, ic-34, and icgv 86388) to tomato spotted wilt virus (tswv) by mechanical and thrips inoculation, under greenhouse conditions, and compare them to the reactions of cultivars sunoleic, georgia green, and the breeding line c11-2-39. tswv infection by mechanical inoculation was visually assessed using an index ranging from 0 (no symptoms) to 4 (apical death). enzyme-linked immunosorbent assay was used to confirm tswv infection from both mechanical and thrips inoculations. ic-10, ic-34, icgv 86388, and c11-2-39 were more resistant than the cultivars sunoleic and georgia green based on mechanical inoculation. upon thrips inoculation only ic-34 and icgv-86388 were infected by tswv, as demonstrated by reverse transcription polymerase chain reaction (rt-pcr), although no symptoms of infection were observed. the peanut breeding lines ic-10, ic-34, and icgv 86388 show higher level of resistance to tswv than cultivar georgia green considered a standard for tswv resistance.
Arranjo espacial do vira-cabe?a do fumo em arapiraca, estado de alagoas
SILVA, JEFFERSON N.;MICHEREFF, SAMI J.;PIO-RIBEIRO, GILVAN;ANDRADE, GENIRA P.;
Fitopatologia Brasileira , 2001, DOI: 10.1590/S0100-41582001000400005
Abstract: the spotted wilt of tobacco (nicotiana tabacum), caused by groundnut ringspot virus (grsv), genus tospovirus, has been observed with high severity in certain areas of the tobacco producing region of alagoas. the spatial pattern of the disease was analysed in two areas (a and b), formed by four parcels each, located in the county of arapiraca. the parcels were evaluated weekly by spatial mapping of healthy and spotted wilt tobacco plants, as well as by the disease incidence, represented by the number of plants with symptoms in relation to the total evaluated plants. through the analyses of ordinary runs and spatial autocorrelation, a random pattern diseased plants was predominantly observed, although aggregation was also detected in a few cases. although the possible effect of infected seedlings in the spatial pattern was not discarded, the most probable hypothesis is that the infections mainly occurred due to the primary inoculum transmitted by viruliferous thrips entering the parcels from external reservoirs.
Sequences of the coat protein gene from brazilian isolates of Papaya ringspot virus
LIMA, ROBERTO C. A.;SOUZA JR., MANOEL T.;PIO-RIBEIRO, GILVAN;LIMA, J. ALBERSIO A.;
Fitopatologia Brasileira , 2002, DOI: 10.1590/S0100-41582002000200009
Abstract: papaya ringspot virus (prsv) is the causal agent of the main papaya (carica papaya) disease in the world. brazil is currently the world's main papaya grower, responsible for about 40% of the worldwide production. resistance to prsv on transgenic plants expressing the prsv coat protein (cp) gene was shown to be dependent on the sequence homology between the cp transgene expressed in the plant genome and the cp gene from the incoming virus, in an isolate-specific fashion. therefore, knowledge of the degree of homology among the cp genes from distinct prsv isolates which are present in a given area is important to guide the development of transgenic papaya for the control of prsv in that area. the objective of the present study was to assess the degree of homology among the prsv cp genes of several brazilian isolates of this virus. papaya and prsv are present in many different ecosystems within brazil. twelve prsv isolates, collected in eight different states from four different geographic regions, were used in this study. the sequences of the cp gene from these isolates were compared among themselves and to the gene used to generate transgenic papaya for brazil. an average degree of homology of 97.3% at the nucleotide sequence was found among the brazilian isolates. when compared to 27 isolates from outside brazil in a homology tree, the brazilian isolates were clustered with australian, hawaiian, and central and north american isolates, with an average degree of homology of 90.7% among them.
Production of polyclonal antisera using recombinant coat proteins of Grapevine leafroll-associated virus 2 and Grapevine virus B
Radaelli, Paula;Fajardo, Thor Vinícius Martins;Nickel, Osmar;Eiras, Marcelo;Pio-Ribeiro, Gilvan;
Pesquisa Agropecuária Brasileira , 2008, DOI: 10.1590/S0100-204X2008001000020
Abstract: the objective of this work was to produce and characterize specific antisera against brazilian isolates of grapevine leafroll-associated virus 2 (glrav-2) and grapevine virus b (gvb), developed from expressed coat proteins (cps) in escherichia coli, and to test their possible use for the detection of these two viruses in diseased grapevines. the coat protein (cp) genes were rt-pcr-amplified, cloned and sequenced. the cp genes were subsequently subcloned, and the recombinant plasmids were used to transform e. coli cells and express the coat proteins. the recombinant coat proteins were purified, and their identities were confirmed by sds-page and western blot and used for rabbit immunizations. antisera raised against these proteins were able to recognize the corresponding recombinant proteins in western blots and to detect glrav-2 and gvb in infected grapevine tissues, by indirect elisa, discriminating healthy and infected grapevines with absorbances (a405) of 0.08/1.15 and 0.12/1.30, respectively. expressing cp genes can yield high amount of viral protein with high antigenicity, and glrav-2 and gvb antisera obtained in this study can allow reliable virus disease diagnosis.
Variabilidade do gene da proteína capsidial de três espécies virais que infectam videiras no Brasil
Radaelli, Paula;Fajardo, Thor V.M;Nickel, Osmar;Eiras, Marcelo;Pio-Ribeiro, Gilvan;
Tropical Plant Pathology , 2009, DOI: 10.1590/S1982-56762009000500002
Abstract: the purpose of this study was to evaluate the variability of three viruses (rupestris stem pitting-associated virus - rspav, grapevine leafroll-associated virus 2 - glrav-2 and grapevine fanleaf virus - gflv) infecting grapevines in brazil, through molecular characterization of the coat protein (cp) gene. dna fragments were amplified comprising the complete cp genes of nine isolates of rspav (780 bp), six of glrav-2 (597 bp) and three of gflv (1515 bp) by rt-pcr, using specific primers for each viral species. the amplified dna fragments were cloned and sequenced. rspav isolates were clustered into four groups by phylogenetic analysis of the nucleotide (nt) sequences of the cp gene, showing identity values ranging from 81 to 99%. for glrav-2, two groups were defined from nt sequences, with identity values ranging from 88 to 99% and for gflv, two groups were defined with identity values ranging from 89 to 98%. the isolates of each viral species studied here were detected by non-radioactive probes labeled with digoxigenin, allowing unambiguous identification of infected samples, independent of the isolate used as template for probe synthesis.
Etiologia e estratégias de controle de viroses do mamoeiro no brasil
LIMA ROBERTO C. A.,LIMA J. ALBERSIO A.,SOUZA JR. MANOEL T.,PIO-RIBEIRO GILVAN
Fitopatologia Brasileira , 2001,
Abstract: As viroses constituem o principal grupo de doen as do mamoeiro (Carica papaya), ocasionando grandes perdas na produ o, podendo chegar à destrui o total das planta es afetadas. Embora mais de dez vírus tenham sido constatados infetando naturalmente o mamoeiro, em todo o mundo, no Brasil, até o presente, foram assinaladas apenas as ocorrências do vírus da mancha anelar do mamoeiro (Papaya ringspot virus, PRSV), do vírus do amarelo letal do mamoeiro (Papaya lethal yellowing virus, PLYV) e do vírus da meleira que se encontra em fase de caracteriza o. A mancha anelar causada pelo PRSV é, inquestionavelmente, o mais importante problema sanitário do mamoeiro. O controle do PRSV mostra-se imprescindível, apesar de bastante difícil, em raz o da sua forma de dissemina o rápida e eficiente por diversas espécies de afídeos e ausência de resistência genética em C. papaya. Na tentativa de controlar o PRSV, várias medidas já foram testadas, n o existindo, até o momento, nenhuma estratégia eficiente e duradoura para seu controle no Brasil. O desenvolvimento de plantas transgênicas de mamoeiro expressando o gene da capa protéica (cp) do PRSV, imunes ao mesmo, abriu nova possibilidade para solu o do problema.
Sequences of the coat protein gene from brazilian isolates of Papaya ringspot virus
LIMA ROBERTO C. A.,SOUZA JR. MANOEL T.,PIO-RIBEIRO GILVAN,LIMA J. ALBERSIO A.
Fitopatologia Brasileira , 2002,
Abstract: Papaya ringspot virus (PRSV) is the causal agent of the main papaya (Carica papaya) disease in the world. Brazil is currently the world's main papaya grower, responsible for about 40% of the worldwide production. Resistance to PRSV on transgenic plants expressing the PRSV coat protein (cp) gene was shown to be dependent on the sequence homology between the cp transgene expressed in the plant genome and the cp gene from the incoming virus, in an isolate-specific fashion. Therefore, knowledge of the degree of homology among the cp genes from distinct PRSV isolates which are present in a given area is important to guide the development of transgenic papaya for the control of PRSV in that area. The objective of the present study was to assess the degree of homology among the PRSV cp genes of several Brazilian isolates of this virus. Papaya and PRSV are present in many different ecosystems within Brazil. Twelve PRSV isolates, collected in eight different states from four different geographic regions, were used in this study. The sequences of the cp gene from these isolates were compared among themselves and to the gene used to generate transgenic papaya for Brazil. An average degree of homology of 97.3% at the nucleotide sequence was found among the Brazilian isolates. When compared to 27 isolates from outside Brazil in a homology tree, the Brazilian isolates were clustered with Australian, Hawaiian, and Central and North American isolates, with an average degree of homology of 90.7% among them.
Arranjo espacial do vira-cabe a do fumo em arapiraca, estado de alagoas
SILVA JEFFERSON N.,MICHEREFF SAMI J.,PIO-RIBEIRO GILVAN,ANDRADE GENIRA P.
Fitopatologia Brasileira , 2001,
Abstract: O vira-cabe a do fumo (Nicotiana tabacum), causado pelo Groundnut ringspot virus (GRSV), do gênero Tospovirus, tem sido observado em alta incidência em determinadas áreas da regi o fumageira do agreste do estado de Alagoas. O arranjo espacial da doen a foi analisado em duas áreas de plantio (A e B), formadas por quatro parcelas cada, localizadas no município de Arapiraca. As parcelas foram avaliadas semanalmente, sendo efetuado o mapeamento espacial de plantas sadias e com sintomas de vira-cabe a, bem como determinada a incidência da doen a, representada pelo número de plantas com sintomas em rela o ao total de plantas avaliadas. Pelas análises de "ordinary runs" e autocorrela o espacial, foi constatada a predominancia do arranjo aleatório de plantas doentes, embora tenha sido detectada agrega o em alguns casos. Embora n o se descarte a possibilidade de mudas infetadas terem influenciado no arranjo da doen a, a hipótese mais provável é que as infec es ocorreram principalmente pelo inóculo primário transmitido por tripes virulíferos entrando nas parcelas, oriundos de reservatórios externos.
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