Sistema de produção agrossilvipastoril: uma experiência em construção.

Um sistema de produção agrossilvipastoril foi implantado em Casa de Pedra, Carnaubal, Ceará. O solo é Neossolos quartzarênicos (areias quartzosas). A vegetação é Carrasco, hiperxerófila, com precipitação de 780 mm por ano. Uma área de 4 ha foi cercada e dividida em três partes: 1ha para cultivo em aléias; 1 ha de reserva legal e 2 ha para o rebanho. A área agrícola foi raleada e a pastoril raleada e rebaixada, com 150 e 350 árvores por hectare respectivamente. A reserva é manejada com seu potencial madeireiro. Foram plantados milho, feijão, gliricídia. A produção foi insignificante devido ao tipo de solo. Na área pastoril, houve produção do estrato herbáceo de forrageiras nativas. A baixa fertilidade natural e ausência de matéria orgânica, são determinantes. Resultados obtidos por um produtor que visitou o Sistema de Produção na Embrapa e implantou em sua propriedade, mostram que para alcançar níveis ótimos de produção, se faz necessário, melhorar a fertilidade do solo com adição de nutrientes e matéria orgânica. Esta adição acontece através da decomposição e incorporação das leiras, folhagem, restolho das árvores, adição de esterco, fixação de nitrogênio pelas leguminosas. O sistema deste produtor inclui sorgo, milho, feijão, palma forrageira, fruteiras além de forrageiras nativas e introduzidas (leucena e gliricídia), que vem sendo produzido regularmente. Tem sido um modelo exemplar para os agricultores vizinhos absolverem a tecnologia proposta. Os conhecimentos inatos dos produtores, aliado ao acesso às informações técnicas, são importantes para melhorar os sistemas agrícolas destas famílias. Através da informação se eleva o índice de adoção de tecnologias com incremento da produção e produtividade, melhoria da qualidade dos produtos, maior desempenho das unidade de produção e trabalhadores rurais, reintegrando-os ao processo produtivo, gerando mais emprego e conquistando mercados, provocando mudanças necessárias para a sobrevivência numa economia aberta e competitiva. Em Casa de Pedra, alguns produtores assimilaram o uso da agricultura sem o fogo e sem o desmatamento. O relato de um produtor que já obtém uma produção aumentada na mesma área, ensina que o sucesso no incremento da produção das culturas reside no acúmulo de matéria orgânica pelo solo

An impact assessment for urban stormwater use

The adoption of stormwater collection and use for a range of non-potable applications requires that the perceived risks, particularly those associated with public health, are addressed. Pollutant impacts have been assessed using E. coli and a scoring system on a scale of 0 to 5 to identify the magnitude of impacts and also the likelihood of exposure to stormwater during different applications. Combining these identifies that low or medium risks are generally predicted except for domestic car washing and occupational irrigation of edible raw food crops where the predicted high risk would necessitate the introduction of remedial action

Tandem E2F Binding Sites in the Promoter of the p107 Cell Cycle Regulator Control p107 Expression and Its Cellular Functions

The retinoblastoma tumor suppressor (Rb) is a potent and ubiquitously expressed cell cycle regulator, but patients with a germline Rb mutation develop a very specific tumor spectrum. This surprising observation raises the possibility that mechanisms that compensate for loss of Rb function are present or activated in many cell types. In particular, p107, a protein related to Rb, has been shown to functionally overlap for loss of Rb in several cellular contexts. To investigate the mechanisms underlying this functional redundancy between Rb and p107 in vivo, we used gene targeting in embryonic stem cells to engineer point mutations in two consensus E2F binding sites in the endogenous p107 promoter. Analysis of normal and mutant cells by gene expression and chromatin immunoprecipitation assays showed that members of the Rb and E2F families directly bound these two sites. Furthermore, we found that these two E2F sites controlled both the repression of p107 in quiescent cells and also its activation in cycling cells, as well as in Rb mutant cells. Cell cycle assays further indicated that activation of p107 transcription during S phase through the two E2F binding sites was critical for controlled cell cycle progression, uncovering a specific role for p107 to slow proliferation in mammalian cells. Direct transcriptional repression of p107 by Rb and E2F family members provides a molecular mechanism for a critical negative feedback loop during cell cycle progression and tumorigenesis. These experiments also suggest novel therapeutic strategies to increase the p107 levels in tumor cells

Conserved genes and pathways in primary human fibroblast strains undergoing replicative and radiation induced senescence

Additional file 3: Figure S3. Regulation of genes of Arrhythmogenic right ventricular cardiomyopathy pathway during senescence induction in HFF strains Genes of the “Arrhythmogenic right ventricular cardiomyopathy” pathway which are significantly up- (green) and down- (red) regulated (log2 fold change >1) during irradiation induced senescence (120 h after 20 Gy irradiation) in HFF strains. Orange color signifies genes which are commonly up-regulated during both, irradiation induced and replicative senescence

A global metagenomic map of urban microbiomes and antimicrobial resistance

We present a global atlas of 4,728 metagenomic samples from mass-transit systems in 60 cities over 3 years, representing the first systematic, worldwide catalog of the urban microbial ecosystem. This atlas provides an annotated, geospatial profile of microbial strains, functional characteristics, antimicrobial resistance (AMR) markers, and genetic elements, including 10,928 viruses, 1,302 bacteria, 2 archaea, and 838,532 CRISPR arrays not found in reference databases. We identified 4,246 known species of urban microorganisms and a consistent set of 31 species found in 97% of samples that were distinct from human commensal organisms. Profiles of AMR genes varied widely in type and density across cities. Cities showed distinct microbial taxonomic signatures that were driven by climate and geographic differences. These results constitute a high-resolution global metagenomic atlas that enables discovery of organisms and genes, highlights potential public health and forensic applications, and provides a culture-independent view of AMR burden in cities

Senescence Regulation by mTOR

International audienceThe senescence program is activated in response to diverse stress stimuli potentially compromising genetic stability and leads to an irreversible cell cycle arrest. The mTOR pathway plays a crucial role in the regulation of cell metabolism and cellular growth. The goal of this chapter is to present evidence linking these two processes, which have one common regulator-the tumor suppressor p53. While the role of mTOR in senescence is still controversial, recent papers have shed new light onto this issue. This review, far from being exhaustive given the complexity of the field, will hopefully stimulate further research in this domain, whose relevance for ageing is becoming increasingly documented