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Registro Completo |
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Biblioteca(s): |
Embrapa Recursos Genéticos e Biotecnologia. |
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Data corrente: |
13/02/2007 |
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Data da última atualização: |
31/01/2013 |
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Autoria: |
SILVA-WERNECK, J. O. |
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Título: |
Investigation of a novel Bacillus thuringiensis toxin. |
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Ano de publicação: |
2006 |
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Fonte/Imprenta: |
2006. |
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Páginas: |
241 f. |
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Idioma: |
Inglês |
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Notas: |
Tese (Doutorado) - University of Cambridge, Cambridge, UK. Orientador: David Ellar. |
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Conteúdo: |
The aim of the present work was to investigate the toxicity, biochemical characteristics, gene and protein contents, and the mechanism of action of toxins from the Brazilian Bacil/us thuringiensis (Bt) strain 8725. This strain has been reported as toxic against the cotton boll weevil (Anthonomus grandis), a severe pest of cotton crops in America, which is considered a recalcitrant target to most of the known Bt toxins. It was serotyped as Bt serovar japonensis and produced spherical crystals that were purified on discontinuous sucrose gradient. 8D8-P AGE analysis of the solubilised inclusions showed two proteins of about 130 kDa which were converted to fragments of between 50 and 70 kDa upon trypsin activation. N-terminal sequencing of a trypsin activated fragment revealed a high leveI of similarity to Cry9 õ-endotoxins. The protein comprising the crystals was found to react positively with a polyclonal antibody raised against a Cry9 toxin. The cry9-like gene was PCR amplified, cloned in Escherichia coli XLlO-Gold, and sequenced. A BLA8T search of the deduced amino acid sequence revealed it to be unique and to have 73% identity to Cry9Ba, 64% identity to Cry9Ea, 63% identity to Cry9Da, and 59% identity to Cry9Ca proteins. .The Cry9-like protein gene was transformed into the acrystalliferous strain Bti IP878/11 where it formed spherical cytoplasmic inclusions as viewed by ~canning electron microscopy. The novel Cry9-like õ-endotoxin was assigned to a new subclass (Cry9Bb) by the Bt Toxin Nomenclature Committee. Modelling of the novel protein sequence produced a 3D model containing three structural domains, similarly to the Cry proteins whose structures have been solved by X-ray crystallography. The similarities and phylogenetic distances of Cry9Bb to Cry9 holotype proteins were determined. The Cry9Bb protein was solubilised under different conditions and activated by A. grandis or Pieris brassicae gut extract or by trypsin at different trypsin:toxin ratios. The biotinylated toxin was used in overlay assays for detection of A. grandis BBMV -bound toxin. Bioassays with native crystals from the 8725 strain, Cry9Bb crystals from the recombinant strain and with solubilised or activated Cry9Bb protein were performed against coleopteran, lepidopteran and dipteran insects. The protein showed no toxicity against most of the insects tested, including the coleopteran A. grandis. Mortality was observed against the lepidopterans Manduca sexta and Anticarsia gemmatalis, although only at high toxin concentrations. The LCso for the recombinant Cry9Bb crystals against M sexta larvae was determined. Cytotoxicity assays of the activated Cry9Bb toxin were performed against Choristoneura fumiferana, M sexta and A. gemmatalis celI lines. The toxin showed no visible effects on the tested celIs. PCR screening revealed that in addition to cry9Bb, Bt strain S725 also contains crylI and vip3 genes. Transcription analysis, using RT-PCR, showed that the crylI gene was transcribed at low levels. Site directed mutagenesis was carried out to replace an alanine found in
Cry9Bb with a proline conserved at that position in alI other Cry9 toxins. The effect of this change was investigated using bioassays against M sexta as welI as analysis of solubilisation, activation, and simulated gastric digestion of the toxin. MenosThe aim of the present work was to investigate the toxicity, biochemical characteristics, gene and protein contents, and the mechanism of action of toxins from the Brazilian Bacil/us thuringiensis (Bt) strain 8725. This strain has been reported as toxic against the cotton boll weevil (Anthonomus grandis), a severe pest of cotton crops in America, which is considered a recalcitrant target to most of the known Bt toxins. It was serotyped as Bt serovar japonensis and produced spherical crystals that were purified on discontinuous sucrose gradient. 8D8-P AGE analysis of the solubilised inclusions showed two proteins of about 130 kDa which were converted to fragments of between 50 and 70 kDa upon trypsin activation. N-terminal sequencing of a trypsin activated fragment revealed a high leveI of similarity to Cry9 õ-endotoxins. The protein comprising the crystals was found to react positively with a polyclonal antibody raised against a Cry9 toxin. The cry9-like gene was PCR amplified, cloned in Escherichia coli XLlO-Gold, and sequenced. A BLA8T search of the deduced amino acid sequence revealed it to be unique and to have 73% identity to Cry9Ba, 64% identity to Cry9Ea, 63% identity to Cry9Da, and 59% identity to Cry9Ca proteins. .The Cry9-like protein gene was transformed into the acrystalliferous strain Bti IP878/11 where it formed spherical cytoplasmic inclusions as viewed by ~canning electron microscopy. The novel Cry9-like õ-endotoxin was assigned to a new subclass (Cry9Bb) by ... Mostrar Tudo |
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Thesagro: |
Bacillus Thuringiensis; Toxina. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 03801nam a2200157 a 4500
001 1187894
005 2013-01-31
008 2006 bl uuuu m 00u1 u #d
100 1 $aSILVA-WERNECK, J. O.
245 $aInvestigation of a novel Bacillus thuringiensis toxin.
260 $a2006.$c2006
300 $a241 f.
500 $aTese (Doutorado) - University of Cambridge, Cambridge, UK. Orientador: David Ellar.
520 $aThe aim of the present work was to investigate the toxicity, biochemical characteristics, gene and protein contents, and the mechanism of action of toxins from the Brazilian Bacil/us thuringiensis (Bt) strain 8725. This strain has been reported as toxic against the cotton boll weevil (Anthonomus grandis), a severe pest of cotton crops in America, which is considered a recalcitrant target to most of the known Bt toxins. It was serotyped as Bt serovar japonensis and produced spherical crystals that were purified on discontinuous sucrose gradient. 8D8-P AGE analysis of the solubilised inclusions showed two proteins of about 130 kDa which were converted to fragments of between 50 and 70 kDa upon trypsin activation. N-terminal sequencing of a trypsin activated fragment revealed a high leveI of similarity to Cry9 õ-endotoxins. The protein comprising the crystals was found to react positively with a polyclonal antibody raised against a Cry9 toxin. The cry9-like gene was PCR amplified, cloned in Escherichia coli XLlO-Gold, and sequenced. A BLA8T search of the deduced amino acid sequence revealed it to be unique and to have 73% identity to Cry9Ba, 64% identity to Cry9Ea, 63% identity to Cry9Da, and 59% identity to Cry9Ca proteins. .The Cry9-like protein gene was transformed into the acrystalliferous strain Bti IP878/11 where it formed spherical cytoplasmic inclusions as viewed by ~canning electron microscopy. The novel Cry9-like õ-endotoxin was assigned to a new subclass (Cry9Bb) by the Bt Toxin Nomenclature Committee. Modelling of the novel protein sequence produced a 3D model containing three structural domains, similarly to the Cry proteins whose structures have been solved by X-ray crystallography. The similarities and phylogenetic distances of Cry9Bb to Cry9 holotype proteins were determined. The Cry9Bb protein was solubilised under different conditions and activated by A. grandis or Pieris brassicae gut extract or by trypsin at different trypsin:toxin ratios. The biotinylated toxin was used in overlay assays for detection of A. grandis BBMV -bound toxin. Bioassays with native crystals from the 8725 strain, Cry9Bb crystals from the recombinant strain and with solubilised or activated Cry9Bb protein were performed against coleopteran, lepidopteran and dipteran insects. The protein showed no toxicity against most of the insects tested, including the coleopteran A. grandis. Mortality was observed against the lepidopterans Manduca sexta and Anticarsia gemmatalis, although only at high toxin concentrations. The LCso for the recombinant Cry9Bb crystals against M sexta larvae was determined. Cytotoxicity assays of the activated Cry9Bb toxin were performed against Choristoneura fumiferana, M sexta and A. gemmatalis celI lines. The toxin showed no visible effects on the tested celIs. PCR screening revealed that in addition to cry9Bb, Bt strain S725 also contains crylI and vip3 genes. Transcription analysis, using RT-PCR, showed that the crylI gene was transcribed at low levels. Site directed mutagenesis was carried out to replace an alanine found in Cry9Bb with a proline conserved at that position in alI other Cry9 toxins. The effect of this change was investigated using bioassays against M sexta as welI as analysis of solubilisation, activation, and simulated gastric digestion of the toxin.
650 $aBacillus Thuringiensis
650 $aToxina
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Registro original: |
Embrapa Recursos Genéticos e Biotecnologia (CENARGEN) |
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Registro Completo
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Biblioteca(s): |
Embrapa Unidades Centrais. |
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Data corrente: |
25/11/2005 |
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Data da última atualização: |
20/08/2018 |
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Autoria: |
SOUZA, R. P. de; RIBEIRO, R. V.; MACHADO, E. C.; OLIVEIRA, R. F. de; SILVEIRA, J. A. G. da. |
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Afiliação: |
Rogéria Pereira de Souza, Instituto Agronômico - IAC/Centro de Pesquisa e Desenvolvimento em Ecofisiologia e Biofísica; Rafael Vasconcelos Ribeiro, Instituto Agronômico - IAC/Centro de Pesquisa e Desenvolvimento em Ecofisiologia e Biofísica; Eduardo Caruso Machado, Instituto Agronômico - IAC/Centro de Pesquisa e Desenvolvimento em Ecofisiologia e Biofísica; Ricardo Ferraz de Oliveira, Universidade de São Paulo - Usp/Escola Superior de Agricultura Luiz de Queiroz - Esalq/Departamento de Ciências Biológicas; Joaquim Albenísio Gomes da Silveira, Universidade Federal do Ceará - UFC/Departamento de Bioquímica e Biologia Molecular. |
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Título: |
Photosynthetic responses of young cashew plants to varying environmental conditions. |
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Ano de publicação: |
2005 |
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Fonte/Imprenta: |
Pesquisa Agropecuária Brasileira, Brasília, DF, v. 40, n. 8, p. 735-744, ago. 2005 |
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Idioma: |
Inglês |
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Notas: |
Título em português: Respostas da fotossíntese à variação das condições ambientais em plantas jovens de cajueiro. |
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Conteúdo: |
The aim of this study was to characterize gas exchange responses of young cashew plants to varying photosynthetic photon flux density (PPFD), temperature, vapor-pressure deficit (VPD), and intercellular CO2 concentration (Ci), under controlled conditions. Daily courses of gas exchange and chlorophyll a fluorescence parameters were measured under natural conditions. Maximum CO2 assimilation rates, under optimal controlled conditions, were about 13 mmol m-2 s-1, with light saturation around 1,000 mmol m-2 s-1. Leaf temperatures between 25oC and 35oC were optimal for photosynthesis. Stomata showed sensitivity to CO2, and a closing response with increasing Ci. Increasing VPD had a small effect on CO2 assimilation rates, with a small decrease above 2.5 kPa. Stomata, however, were strongly affected by VPD, exhibiting gradual closure above 1.5 kPa. The reduced stomatal conductances at high VPD were efficient in restricting water losses by transpiration, demonstrating the species adaptability to dry environments. Under natural irradiance, CO2 assimilation rates were saturated in early morning, following thereafter the PPFD changes. Transient Fv/Fm decreases were registered around 11h, indicating the occurrence of photoinhibition. Decreases of excitation capture efficiency, decreases of effective quantum yield of photosystem II, and increases in non-photochemical quenching were consistent with the occurrence of photoprotection under excessive irradiance levels. |
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Palavras-Chave: |
chlorophyll fluorescence; déficit da pressão de vapor; fluorescência da clorofila; trocas gasosas; vapor-pressure deficit. |
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Thesagro: |
Anacardium Occidentale; Temperatura. |
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Thesaurus NAL: |
gas exchange; temperature. |
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Categoria do assunto: |
-- |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/107668/1/Photosynthetic.pdf
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Marc: |
LEADER 02468naa a2200289 a 4500
001 1116452
005 2018-08-20
008 2005 bl uuuu u00u1 u #d
100 1 $aSOUZA, R. P. de
245 $aPhotosynthetic responses of young cashew plants to varying environmental conditions.
260 $c2005
500 $aTítulo em português: Respostas da fotossíntese à variação das condições ambientais em plantas jovens de cajueiro.
520 $aThe aim of this study was to characterize gas exchange responses of young cashew plants to varying photosynthetic photon flux density (PPFD), temperature, vapor-pressure deficit (VPD), and intercellular CO2 concentration (Ci), under controlled conditions. Daily courses of gas exchange and chlorophyll a fluorescence parameters were measured under natural conditions. Maximum CO2 assimilation rates, under optimal controlled conditions, were about 13 mmol m-2 s-1, with light saturation around 1,000 mmol m-2 s-1. Leaf temperatures between 25oC and 35oC were optimal for photosynthesis. Stomata showed sensitivity to CO2, and a closing response with increasing Ci. Increasing VPD had a small effect on CO2 assimilation rates, with a small decrease above 2.5 kPa. Stomata, however, were strongly affected by VPD, exhibiting gradual closure above 1.5 kPa. The reduced stomatal conductances at high VPD were efficient in restricting water losses by transpiration, demonstrating the species adaptability to dry environments. Under natural irradiance, CO2 assimilation rates were saturated in early morning, following thereafter the PPFD changes. Transient Fv/Fm decreases were registered around 11h, indicating the occurrence of photoinhibition. Decreases of excitation capture efficiency, decreases of effective quantum yield of photosystem II, and increases in non-photochemical quenching were consistent with the occurrence of photoprotection under excessive irradiance levels.
650 $agas exchange
650 $atemperature
650 $aAnacardium Occidentale
650 $aTemperatura
653 $achlorophyll fluorescence
653 $adéficit da pressão de vapor
653 $afluorescência da clorofila
653 $atrocas gasosas
653 $avapor-pressure deficit
700 1 $aRIBEIRO, R. V.
700 1 $aMACHADO, E. C.
700 1 $aOLIVEIRA, R. F. de
700 1 $aSILVEIRA, J. A. G. da
773 $tPesquisa Agropecuária Brasileira, Brasília, DF$gv. 40, n. 8, p. 735-744, ago. 2005
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Registro original: |
Embrapa Unidades Centrais (AI-SEDE) |
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ID |
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Tipo/Formato |
Classificação |
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Registro completo
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Biblioteca(s): |
Catálogo Coletivo de Periódicos Embrapa; Embrapa Amazônia Oriental. |
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Identificador: |
1266 |
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Data corrente: |
09/05/2002 |
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Data da última atualização: |
20/10/2015 |
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Código do título: |
4700007 |
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ISSN: |
0373-7896 |
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Código CCN: |
098511-2 |
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Título e Subtítulo: |
BERICHTE DES GEOBOTANISCHEN INSTITUTES DER EIBGENOESSISCHEN HOCHSCHULE STIFTUNG RUEBEL |
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Título anterior: |
BERICHT UBER DAS GEOBOTANISCHE FORCHUNGSINSTITUL RUBEL IN ZURICH |
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Entidade: |
Institut der Eide Techn. Hochschule |
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Local de publicação: |
Zurich, Suica |
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Periodicidade: |
irregular |
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Inicio de publicação: |
1960 |
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Coleções da unidade: |
Embrapa Amazônia Oriental
1960 31; 1961 32; 1962 33; 1963 34; 1965 36; 1967 37; 1968 38; 1969 39; 1970 40; 1972 41
Classificação: 581.05B31 |
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