Selection of superior cacao trees at the cacao plantations in Bahia, Brazil

Em 1953, o então Instituto Agronómico do Leste, hoje Instituto de Pesquisas e Experimentação Agropecuárias do Leste, do Ministério da Agricultura, iniciou o controle de cacaueiro no Sul da Bahia, visando a selecioná-los quanto a produção e resistência a podridão parda. Este programa desenvolveu-se durante onze anos e 1.235 árvores foram rigorosamente controladas. Critérios pré-estabelecidos exigiam marcada superioridade das plantas a serem eleitas, que deveriam dar: 1) média anual de produção de amêndoas secas ≥ 4,0 kg; 2) média anual de produção de frutos são ≥ 100; 3) índices de frutos ≤ 40; 4) percentagem média de frutos infectados ≤ 12. Cento e noventa e sete árvores foram selecionadas após julgamento dos dados de controle. Essas matrizes foram propagadas assexualmente e incluídas na coleção de clones da Estação Experimentação de Juçari. Estreitados com base estatística os critérios de seleção previamente estabelecidos e considerados outros, foi feita uma resseleção que evidenciou, como excepcionais, 28 árvores. Na Estação Experimental de Juçari foram instalados um experimento de competição de clones e uma competição de progênies endocriadas, das seleções SIAL, que já começam a fornecer dados informativos de produtividade.In Brazil, the State of Bahia with over 450,000 hectares under cultivation produces about 96% of all Brazilian cocoa; however, the average annual seed production is very low, around 0.450 kg of dry beans per tree. In 1953 the Instituto de Pesquisas e Experimentação Agropecuárias do Leste, started its cocoa selection program in the cocoa plantations of southern Bahia. The objectives were to improve yields per tree and resistance to Phytophthora pod rot. Selection was based on the following criteria: 1. High pod numbers; 2. Desirable pod shape; 3. Health of trees and pods, especially those with a low incidence of Phytophthora pod rot. Individual tree and the harvest data were recorded for comparative analysis. The following criteria of superiority were preestablished: 1. Average annual production of dry cocoa beans ≥ 4.0 kg. 2. Average annual production ≥ 100 fruits. 3. Fruit index ≤ 40. 4. Average percentage of infected fruits ≤ 12 or less. Pod production and resistance Phytophthora pod rot has been recorded for at least seven years on 1235 cocoa trees. Records on many these trees have been maintained for as long as eleven years. From the 1235 trees one hundred ninety seven were selected for asexual propagation and inclusion in the collection of cocoa clones at the Experimental Station of Juçari. From the 190 clones 28 exceptional trees were chosen using an appropriate statistical process of data on selection pod numbers, seed production, fruit index, a percentage of fruit infected by Phytophthora pod rot, tree population density, intensity to shade and stem appearance. The special criteria developed to evaluate each index are discussed as well as the degree of transmissibility of desired characteristics to a descendent population obtained by rooted cuttings.

Diversity of metalloproteinases in Bothrops neuwiedi snake venom transcripts: evidences for recombination between different classes of SVMPs

<p>Abstract</p> <p>Background</p> <p>Snake venom metalloproteinases (SVMPs) are widely distributed in snake venoms and are versatile toxins, targeting many important elements involved in hemostasis, such as basement membrane proteins, clotting proteins, platelets, endothelial and inflammatory cells. The functional diversity of SVMPs is in part due to the structural organization of different combinations of catalytic, disintegrin, disintegrin-like and cysteine-rich domains, which categorizes SVMPs in 3 classes of precursor molecules (PI, PII and PIII) further divided in 11 subclasses, 6 of them belonging to PII group. This heterogeneity is currently correlated to genetic accelerated evolution and post-translational modifications.</p> <p>Results</p> <p>Thirty-one SVMP cDNAs were full length cloned from a single specimen of <it>Bothrops neuwiedi </it>snake, sequenced and grouped in eleven distinct sequences and further analyzed by cladistic analysis. Class P-I and class P-III sequences presented the expected tree topology for fibrinolytic and hemorrhagic SVMPs, respectively. In opposition, three distinct segregations were observed for class P-II sequences. P-IIb showed the typical segregation of class P-II SVMPs. However, P-IIa grouped with class P-I cDNAs presenting a 100% identity in the 365 bp at their 5' ends, suggesting post-transcription events for interclass recombination. In addition, catalytic domain of P-IIx sequences segregated with non-hemorrhagic class P-III SVMPs while their disintegrin domain grouped with other class P-II disintegrin domains suggesting independent evolution of catalytic and disintegrin domains. Complementary regions within cDNA sequences were noted and may participate in recombination either at DNA or RNA levels. Proteins predicted by these cDNAs show the main features of the correspondent classes of SVMP, but P-IIb and P-IIx included two additional cysteines cysteines at the C-termini of the disintegrin domains in positions not yet described.</p> <p>Conclusions</p> <p>In <it>B. neuwiedi </it>venom gland, class P-II SVMPs were represented by three different types of transcripts that may have arisen by interclass recombination with P-I and P-III sequences after the divergence of the different classes of SVMPs. Our observations indicate that exon shuffling or post-transcriptional mechanisms may be driving these recombinations generating new functional possibilities for this complex group of snake toxins.</p

Promiscuous Gene Expression in the Thymus: The Root of Central Tolerance

The thymus is a complex organ with an epithelium formed by two main cell types, the cortical thymic epithelial (cTECs) and medullary thymic epithelial cells (mTECs), referred to as stroma. Immature thymocytes arising from the bone marrow, macrophages and dendritic cells also populate the thymus. Thymocytes evolve to mature T cells featuring cell differentiation antigens (CDs), which characterize the phenotypically distinct stages, defined as double-negative (DN), double positive (DP) and single positive (SP), based on expression of the coreceptors CD4 and CD8. The thymus is therefore implicated in T cell differentiation and during development into T cells thymocytes are in close association with the stroma. Recent evidence showed that mTECs express a diverse set of genes coding for parenchymal organ specific proteins. This phenomenon has been termed promiscuous gene expression (PGE) and has led to the reconsideration of the role of the thymus in central T cell tolerance to self-antigens, which prevents autoimmunity. The evidence of PGE is causing a reanalysis in the scope of central tolerance understanding. We summarize the evidence of PGE in the thymus, focusing particularly the use of cDNA microarray technology for the broad characterization of gene expression and demarcation of PGE emergence during thymus ontogeny

A ética do silêncio racial no contexto urbano: políticas públicas e desigualdade social no Recife, 1900-1940

Mais de meio século após o preconceito racial ter se tornado o principal alvo dos movimentos urbanos pelos direitos civis nos Estados Unidos e na África do Sul, e décadas depois do surgimento dos movimentos negros contemporâneos no Brasil, o conjunto de ferramentas legislativas criado no Brasil para promover o direito à cidade ainda adere à longa tradição brasileira de silêncio acerca da questão racial. Este artigo propõe iniciar uma exploração das raízes históricas desse fenômeno, remontando ao surgimento do silêncio sobre a questão racial na política urbana do Recife, Brasil, durante a primeira metade do século XX. O Recife foi eé um exemplo paradigmático do processo pelo qual uma cidade amplamente marcada por traços negros e africanos chegou a ser definida política e legalmente como um espaço pobre, subdesenvolvido e racialmente neutro, onde as desigualdades sociais originaram na exclusão capitalista, e não na escravidão e nas ideologias do racismo científico. Neste sentido, Recife lança luzes sobre a política urbana que se gerou sob a sombra do silêncio racial.More than half a century after racial prejudice became central to urban civil rights movements in the United States and South Africa, and decades after the emergence of Brazil’s contemporary Black movements, Brazil's internationally recognized body of rights-to-the-city legislation still adheres to the country's long historical tradition of racial silence. This article explores the historical roots of this phenomenon by focusing on the emergence of racial silence in Recife, Brazil during the first half of the 20th Century. Recife was and remains a paradigmatic example of the process through which a city marked by its Black and African roots came to be legally and politically defined as a poor, underdeveloped and racially neutral space, where social inequalities derived from capitalist exclusion rather than from slavery and scientific racism. As such, Recife'sexperience sheds light on the urban policies that were generated in the shadow of racial silence