Trajetória da pesquisa cafeeira no Brasil - 1932 a 2012.

A mensuração dos impactos das inovações tecnológicas é relevante para a revisão das diretrizes dos programas das Instituições de Pesquisa e Desenvolvimento, bem como para as Instituições relacionadas à assistência técnica e extensão rural. Para avaliar os impactos das inovações, sejam ambientais ou socioeconômicos, é necessário estudar a evolução da pesquisa e identificar as tecnologias que resultaram em pontos de ruptura para o desenvolvimento setorial. Tendo em vista a relevância histórica do setor cafeeiro para a economia brasileira, este estudo identificou as tecnologias que representaram pontos de ruptura no desenvolvimento da cafeicultura nacional, delineou a trajetória da pesquisa com o café no Brasil, no período 1932 a 2012, e identificou regionalmente a evolução do emprego das tecnologias desenvolvidas para o setor

Structural diversity of supercoiled DNA

By regulating access to the genetic code, DNA supercoiling strongly affects DNA metabolism. Despite its importance, however, much about supercoiled DNA (positively supercoiled DNA, in particular) remains unknown. Here we use electron cryo-tomography together with biochemical analyses to investigate structures of individual purified DNA min icircle topoisomers with defined degrees of supercoiling. Our results reveal that each topoisomer, negative or positive, adopts a unique and surprisingly wide distribution of three-dimensional conformations. Moreover, we uncover striking differences in how the topoisomers handle torsional stress. As negative supercoiling increases, bases are increasingly exposed. Beyond a sharp supercoiling threshold, we also detect exposed bases in positively supercoiled DNA. Molecular dynamics simulations independently confirm the conformational heterogeneity and provide atomistic insight into the flexibility of supercoiled DNA. Our integrated approach reveals the three-dimensional structures of DNA that are essential for its function

Oligomeric Coiled-Coil Adhesin YadA Is a Double-Edged Sword

Yersinia adhesin A (YadA) is an essential virulence factor for the food-borne pathogens Yersinia enterocolitica and Yersinia pseudotuberculosis. Suprisingly, it is a pseudogene in Yersinia pestis. Even more intriguing, the introduction of a functional yadA gene in Y. pestis EV76 was shown to correlate with a decrease in virulence in a mouse model. Here, we report that wild type (wt) Y. enterocolitica E40, as well as YadA-deprived E40 induced the synthesis of neutrophil extracellular traps (NETs) upon contact with neutrophils, but only YadA-expressing Y. enterocolitica adhered to NETs and were killed. As binding seemed to be a prerequisite for killing, we searched for YadA-binding substrates and detected the presence of collagen within NETs. E40 bacteria expressing V98D,N99A mutant YadA with a severely reduced ability to bind collagen were found to be more resistant to killing, suggesting that collagen binding contributes significantly to sensitivity to NETs. Wt Y. pestis EV76 were resistant to killing by NETs, while recombinant EV76 expressing YadA from either Y. pseudotuberculosis or Y. enterocolitica were sensitive to killing by NETs, outlining the importance of YadA for susceptibility to NET-dependent killing. Recombinant EV76 endowed with YadA from Y. enterocolitica were also less virulent for the mouse than wt EV76, as shown before. In addition, EV76 carrying wt YadA were less virulent for the mouse than EV76 expressing YadAV98D,N99A. The observation that YadA makes Yersinia sensitive to NETs provides an explanation as for why evolution selected for the inactivation of yadA in the flea-borne Y. pestis and clarifies an old enigma. Since YadA imposes the same cost to the food-borne Yersinia but was nevertheless conserved by evolution, this observation also illustrates the duality of some virulence functions

Bacterial Flagella: Twist and Stick, or Dodge across the Kingdoms

The flagellum organelle is an intricate multiprotein assembly best known for its rotational propulsion of bacteria. However, recent studies have expanded our knowledge of other functions in pathogenic contexts, particularly adherence and immune modulation, e.g., for Salmonella enterica, Campylobacter jejuni, Pseudomonas aeruginosa, and Escherichia coli. Flagella-mediated adherence is important in host colonisation for several plant and animal pathogens, but the specific interactions that promote flagella binding to such diverse host tissues has remained elusive. Recent work has shown that the organelles act like probes that find favourable surface topologies to initiate binding. An emerging theme is that more general properties, such as ionic charge of repetitive binding epitopes and rotational force, allow interactions with plasma membrane components. At the same time, flagellin monomers are important inducers of plant and animal innate immunity: variation in their recognition impacts the course and outcome of infections in hosts from both kingdoms. Bacteria have evolved different strategies to evade or even promote this specific recognition, with some important differences shown for phytopathogens. These studies have provided a wider appreciation of the functions of bacterial flagella in the context of both plant and animal reservoirs

Custos de produção de café nas principais regiões produtoras do Brasil.

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Importância e encadeamento dos setores de produção e abate e processamento da cadeia suinícola em Minas Gerais

O objetivo deste estudo foi determinar a importância e os encadeamentos dos setores de produção e abate e processamento da cadeia suinícola em Minas Gerais, nos anos de 1980 e 1995, por meio dos índices de Rasmussen-Hirschman, do campo de influência e do índice puro de ligação (GHS). De acordo com os resultados, ambos os setores analisados foram considerados setores-chave com base apenas no índice de Rasmussen-Hirschman e no campo de influência, ou seja, apresentaram maior relevância quando considerados os seus impactos na demanda final e os seus poderes de encadeamento na economia. Apesar de não terem sido considerados setores-chave pelo GHS, os setores de produção e abate e processamento apresentaram grande potencialidade de impactos para trás. Em face desses resultados e dado que esses setores continuaram aumentando a sua participação na economia de Minas Gerais nos anos subseqüentes a 1995, tem-se indicação de que estes devam ter prioridade na alocação de recursos e na estratégia de promoções industriais por meio de políticas estaduais.<br>The main objective of this study was to establish the importance and the enchainment of the production sector and butchery/making up sector of pork chain in Minas Gerais, in the years of 1980 and 1995, applying the Rasmussen-Hirschman index, the influence field index and GHS index. The results showed that both sectors were considered key sectors only by the Rasmussen-Hirschman index and the influence field index, i.e., they presented greater importance when observed its impacts on the final demand and its power of enchainment in the economy. Despite not being considered key sectors by the GHS index, they presented great potential of backward impacts. This result, and the fact that the participation of these sectors had been increasing in the Minas Gerais economy since 1995, suggests that those sectors the state policy makers need to give priority in resources allocation and in the strategy for the industrial development