Os pecuaristas e suas redes de conhecimento e informação.

Essa pesquisda tem como objetivo identificar e entender "como" as redes de conhecimento e informacao dos pecuaristas sao construidas, socialmente, e suas relacoes com o Centro Nacional de Pesquisa de Gado de Corte da Empresa Brasileira de Pesquisa Agropecuaria (Embrapa Gado de Corte), visando ao desenvolvimento de um modelo conceitual com enfoque participativo para gerar e transferir tecnologia. Pecuaristas pertencentes a duas regioes ecologicamente distintas (Campo Grande e Pantanal, Mato Grosso do Sul) constituiram-se como modelos sociais para obtencao dos dados. Os estudos de casos, agregados a aplicacao previa de um questionario a uma amostra das populacoes, formaram a base para as sinteses das redes de informacao. Aplicaram-se analise multivariadas (fatorial e de "cluster") para facilitar a identificacao de grupos e selecionar casos representativos. Os resultados indicaram que cada grupo desenvolve seu proprio sistema de informacao. As redes sao complexas e construidas na base de relacionamentos, interfaces e ligacoes sociais que envolvem necessidades, valores, crencas, tempo disponivel, educacao e preferencias, porem sempre marcadas pela presenca de "pessoas de confianca". A comunicacao informal e preferida entre os produtores que , em geral, nao gostam de ler. A participacao da Embrapa Gado de Corte pode ser considerada periferica e indireta nas redes de informacao.bitstream/item/104793/1/Pecuarista-e-suas-redes-de-conhecimento.pd

Proteomic profile of the fungus Moniliophthora perniciosa in response to PR10 from Theobroma cacao : [Abstract R9140]

Witches' broom disease is caused by the hemibiotrophic basidiomycete Moniliophthora perniciosa. This pathogen is the main cause of the decline in cocoa production, and consequently of social, economic and environmental problems. The transcriptomic program of cacao allowed the identification of a pathogenesis-related 10 protein. The corresponding recombinant protein expressed in Escherichia coli BL21 showed a strong antifungal activity in vitro against M. perniciosa. Here, we developed a proteomic analysis of M. perniciosa proteins expressed in the presence of recombinant TcPR10. M. perniciosa was grown in CPD 2% agar medium; after 15 days, the fungal hyphae were broken and were brought together with 3 ?g/mL of TcPR10 for 1h. After this time, the total proteins of the hyphae were extracted using the ADP method, followed by a simple cleaning using the method of SDS-dense and phenol. The quantification was made using a 2-D quantification kit. The proteins were extracted in triplicate and separated using a 12% bi-dimensional SDS-PAGE gel. The 2D map analysis showed approximately 300 "spots" per gel (control and one hour treatment) with differential protein expression pattern. The analysis using a mass spectrometry (naniESI-Q-TOF) was made for the identification of the spots. We identified several proteins involved in fungal metabolism, carbohydrates/proteins metabolism, related proteins to growth and phytotoxics proteins. More spots have been identified to better understand the mechanism of fungi response to protein PR10. (Résumé d'auteur

The cysteine protease TcCYSPR04 T. cacao accumulates in senescent leaves and change the biotrophic phase for saprophytic tissues infected by M. perniciosa

A cysteine proteinase named TcCYSPR04 was identified in a cDNA library of the Theobroma cacao-Moniliophthora perniciosa interaction, in the ESTtik-CIRAD database and in the cacao genome of MARS. TcCYSPR04 presents an ORF of 1068 bp encoding protein with: (i) a molecular weight and isoelectric point of 39 kDa and 5;43, respectively; (ii) a signal peptide with a probable cleavage site between the amino acids 19 and 20; (iii) an inhibitory domain between amino acids 56 and 112; and (iv) a catalytic domain between amino acids 158 and 353. TcCYSPR04 may be secreted or cytoplasmic. According to the literature, the cysteine proteases may be involved in cell differentiation, senescence, and programmed cell death-PCD. The catalytic domain is highly conserved among cysteine proteases and was subcloned into pET28a expression vector . The corresponding protein was expressed in strain Escherichia coli BL21 (DE3) and purified by affinity column His-Trap. Polyclonal antibodies against the recombinant protein were produced in rabbits and purified by immunoadsorption. Total proteins were extracted from apoplastic fluid of healthy and infected leaves of resistant and susceptible varieties of cacau. Proteins were subjected to electrophoresis on SDS-PAGE 15%, and immunoblot using the serum anti-TcCYSPR04.: TcCYSPR04 was imunodetected in senescent leaves infected by M. perniciosa at different development stages and in apoplastic fluid. According to these results, TcCYSPR04 may participate in plant senescence, cell death and defense in response to pathogen attack. (Texte intégral

Investigation of element-specific and bulk magnetism, electronic and crystal structures of La{0.70}Ca{0.30}Mn{1-x}Cr{x}O{3}

The magnetic interactions in La{0.70}Ca{0.30}Mn{1-x}Cr{x}O{3} (x = 0.15, 0.50 and 0.70) are investigated by x-ray absorption spectroscopy (XAS), x-ray magnetic circular dichroism (XMCD), high-resolution x-ray powder diffraction, and bulk magnetization measurements. XAS in the Mn and Cr L{2,3} edges support stable single valent Cr{3+} ions and a varying Mn valence state with x, while the O K edge XAS spectrum reveals local maxima in the O 2p density of states close to the Fermi level due to mixing with Mn and Cr 3d states. A robust antiferromagnetic state is found for x=0.70 below TN = 258 K. For x=0.15, combined XMCD and bulk magnetization measurements indicate a fully polarized ferrimagnetic state for the Mn and Cr spins below Tc=224 K. For x=0.50, a reduced ferrimagnetic component dominated by Mn spins is present below Tc=154 K. No evidence of lattice anomalies due to cooperative charge and orbital orderings is found by x-ray diffraction for all samples. The magnetic properties of this system are rationalized in terms of a competition of ferromagnetic Mn-Mn double exchange and antiferromagnetic Cr-Cr and Cr-Mn superexchange interactions.Comment: 25 pages, 9 figure

A new desiccation-related protein identified by proteomics in the phylloplane of Theobroma cacao

Currently, 20 millions of people from producing countries, such as Brazil, depend directly on cacao (Theobroma cacao L.) for their survival. The witches' broom disease caused by the fungus Moniliophthora perniciosa had drastic consequences on the socio-economic and environmental development of the affected regions, such as the Bahia State. The disease begins with the germination of the basidiospores on the leaf surface (or phylloplane), followed by the penetration of the germination tube into the intercellular space and the colonization of the plant tissues by the mycelium (biotrophic phase). It has been suggested that the phylloplane is one of the first battlefield of the host and pathogen, and the first interface between plant and environment. Here, we identify by SDS-PAGE/MS/MS, the cacao phylloplane proteins, using two different cacao varieties, one susceptible (Catongo) and one resistant (CCN51) to M. perniciosa. One of our objectives was to quantify the small glandular trichomes (SGTs) in relation with the plant resistance/susceptibility to M.perniciosa. Six hundred resistant cacao leaves were collected and washed in distilled water for 30 seconds. Proteins were extracted from filtered and dried washing, and analyzed on SDS-PAGE. The bands were excised from the gel, subjected to reduction/alkylation and tryptic digestion, and then the peptides were analyzed by mass spectrometry on Micromass ESI-Q-Tof Micro (Waters). The more abundant band (25-35 kDa) was sequenced by MS/MS and resulted in eight peptides, corresponding to a new basic protein of 310 amino acids, with a molecular mass of 33.7 kDa and a theoretical pI of 10.25. This protein contains a probable signal peptide cleavage site between the amino acids 24 and 25. The amino acid sequence revealed similarity to a protein related to desiccation tolerance characterized in pollen-grain of Medicago. Histology was performed on CCN51 and Catongo leaves, to obtain the rate of occurrence of SGTs. CCN51 and Catongo presented an average of 1500 and 700 SGTs/cm2, respectively. The role of the proteins involved in tolerance to desiccation or present in the phylloplane of T. cacao are discussed. (Texte intégral