The heavy metal cadmium is very toxic to biological systems. Although its effect on the growth of microorganisms and plants has been investigated, the response of antioxidant enzymes of Aspergillus nidulans to cadmium is not well documented. We have studied the effect of cadmium (supplied as CdCl(2)) on catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR). 0.005 mM CdCl(2) had a very slight stimulatory effect on the growth rate of A. nidulans, but at concentrations above 0.025 mM, growth was totally inhibited. The accumulation of Cd within the mycelium was directly correlated with the increase in the concentration of CdC(2) used in the treatments. Although a cadmium-stimulated increase in SOD activity was observed, there was no change in the relative proportions of the individual Mn-SOD isoenzymes. Higher concentrations of CdCl(2) induced a small increase in total CAT activity, but there was a major increase in one isoenzymic form, that could be separated by gel electrophoresis. GR activity increased significantly following treatment with the highest concentration (0.05 mM) of CdCl(2). The increases in SOD, CAT, and GR activities suggest that CdCl(2) induces the formation of reactive oxygen species inside the mycelia of A. nidulans.

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Helicobacter pylori infection is responsible for gastric carcinogenesis but host factors are also implicated. IQGAP1, a scaffolding protein of the adherens junctions interacting with E-cadherin, regulates cellular plasticity and proliferation. In mice, IQGAP1 deficiency leads to gastric hyperplasia. The aim of this study was to elucidate the consequences of IQGAP1 deletion on H. pylori-induced gastric carcinogenesis.Transgenic mice deleted for iqgap1 and WT littermates were infected with Helicobacter sp., and histopathological analyses of the gastric mucosa were performed. IQGAP1 and E-cadherin expression was evaluated in gastric tissues and in gastric epithelial cell lines in response to H. pylori infection. The consequences of IQGAP1 deletion on gastric epithelial cell behaviour and on the acquisition of cancer stem cell (CSC)-like properties were evaluated. After one year of infection, iqgap1+/- mice developed more preneoplastic lesions and up to 8 times more gastro-intestinal neoplasia (GIN) than WT littermates. H. pylori infection induced IQGAP1 and E-cadherin delocalization from cell-cell junctions. In vitro, knock-down of IQGAP1 favoured the acquisition of a mesenchymal phenotype and CSC-like properties induced by H. pylori infection.Our results indicate that alterations in IQGAP1 signalling promote the emergence of CSCs and gastric adenocarcinoma development in the context of an H. pylori infection.

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ResumoA despeito da visão romântica que domina o senso comum, sobre a homogeneidade e a virgindade da floresta amazônica, as paisagens dessa região são caracterizadas pela diversidade e pela longa convivência com o ser humano. Por meio da complementação das perspectivas evolutivas, históricas e sociais, o presente artigo se propõe a caracterizar as diferentes dinâmicas de ocupação nessas paisagens, buscando compreender como o desenvolvimento das tecnologias e da organização sócio-política foram capazes de modificar as paisagens no passado e como o fazem atualmente. Os dados foram analisados em função de um sequenciamento temporal que abrange desde a chegada do ser humano à Amazônia até os dias de hoje. Três dinâmicas de ocupação distintas foram caracterizadas em função dos diferentes níveis de transformação da paisagem: Dinâmica da Diversificação (9000 a.C. a 1600 d.C.); Dinâmica da Simplificação (1600 a 1960 d.C.) e Dinâmica da Supressão (a partir de 1960 d.C.).Palavras-chave: Amazônia, paisagem, ocupação humana. AbstractDespite the romantic common sense view of the Amazon forest as an uniform and pristine environment, its landscapes are characterized by both diversity and long coexistence with human beings. Employing evolutionary, historical, and social approaches, this article aims to characterize the diverse settlement dynamics in the Amazon landscapes, from the arrival of the first human groups to the present, in order to understand how social development and the advance of new technologies were responsible for landscape changes in the past, and how it happens today. Three distinct settlement dynamics were observed, considering different levels of landscape transformation, along with the historical contexts: (1) Dynamic of Diversification (9000 BC to 1600 AD); (2) Dynamic of Simplification (1600 to 1960 AD); and (3) Dynamic of Suppression (from 1960 AD onwards).Keywords: Amazon, landscape, human settlement. ResumenA pesar de la visión romántica que domina el sentido común, sobre la uniformidad y la virginidad de la selva amazónica, paisajes de esta región se caracterizan por la diversidad y la larga convivencia con los seres humanos. A través de la complementariedad de Amazônica 1 (1

Aiming at contributing to technological improvements in plant fiber processing methods, this paper reports research work on the obtainment of more efficient pectinase-producing fungi strains. More specifically, this work reports the analysis of 18 strains of filamentous fungi, with the purpose of obtaining enzymes for textile fibers degumming. The strains were evaluated for production of pectinolytic enzymes under several growth conditions (culture medium and growth temperature). Production of pectinases was measured by an enzymatic index (EI) in solid pectin medium. Among the tested strains, Penicillium chrysogenum IFO 4626 (Q 176) showed the best performance. Genetic improvement of this strain was carried out to increase its pectinase production, while keeping cellulase activity down to a negligible level, since cellulases are known to decrease the resistance of the fiber. Variability was induced through several cycles of mutation and selection by exposing conidea to ultraviolet light (UV). We selected 39 out of 390 isolated colonies. Resulting mutants produced nine times more pectin lyase (PL) than the original strain in terms of PL specific activity, and five times more in terms of PL activity (i.e. mmoles liberated per minute of reaction per mL of medium). Periodically, mutant performance was evaluated in solid pectin medium. Genetic stability was maintained for four years after isolation.

RESUMO: A lisina é um aminoácido essencial cuja via de biossíntese faz parte da via metabólica do ácido aspártico, pela qual são também sintetizados os aminoácidos treonina, metionina e isoleucina. Além disso, a lisina é o principal aminoácido limitante em todos os cereais e por cerca de 30 anos a via do ácido aspártico tem sido estudada em plantas, com o intuito de desvendar e caracterizar os principais pontos chave na regulação das vias de biossíntese desses aminoácidos. Duas etapas distintas, uma primeira originada a partir do desenvolvimento da cultura de tecidos (anos 70-80) e a segunda a partir do desenvolvimento de técnicas para a transformação de plantas (anos 90), permitiram que mutantes bioquímicos e plantas trangênicas fossem produzidos com alterações específicas em passos metabólicos chave, levando à superprodução e acúmulo de treonina em vários tecidos das plantas. Entretanto, a acumulação de lisina em sementes não foi obtida. Tal fato, associado a estudos bioquímicos da via de degradação da lisina em cereais e em leguminosas, indicou que a manipulação da degradação seria tão ou mais importante que a manipulação da biossíntese de lisina para o acúmulo deste aminoácido em sementes dos cereais . Em milho, o uso e estudo de outros mutantes tais como o opaco-2 e variedades QPM (Quality Protein Maize) contribuíram significativamente para a compreensão dos eventos regulatórios. As estratégias para a obtenção de materiais ricos em lisina e sua relevância à manipulação de outros aminoácidos são revisados. Palavras-chave: lisina, nutrição, aminoácidos essenciais, cereais MANIPULATING CEREAL CROPS FOR HIGH LYSINE ACCUMULATION IN SEEDSABSTRACT: The nutrition value of a protein is directly related to its amino acid composition. Some of these amino acids, termed essential amino acids, cannot be synthesized by humans and therefore must be supplied in the diet for adults and in particular for infants and children. Lysine is an essential amino acid synthesized via the aspartic acid metabolic pathway, in which threonine, methionine and isoleucine are also endproducts. Moreover, lysine is the first limiting amino acid in all cereal grains. For over 30 years, the aspartic acid metabolic pathway has been studied in higher plants with the aim of identifying and characterizing the key regulatory points controlling the biosynthetic pathway. Two clear distinct time periods, one begining with the development of tissue culture techniques (1970-80's) and the second with the development of plant transformation techniques (90's), has encouraged the production of biochemical mutants and transgenic plants with specific alterations in key enzymes of the pathway, leading to the overproduction and accumulation of threonine in all plant tissues. However, the accumulation of lysine in seeds has been particularly difficult to achieve. Such an observation, associated with the recent biochemical studies on lysine degradation in cereal and legume plant species, has indicated that the manipulation of lysine degradation is as important as t...

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