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Oeiras, Portugal

Tavares S.,University of Lisbon | Vesentini D.,ITQB | Fernandes J.C.,University of Lisbon | Ferreira R.B.,University of Lisbon | And 3 more authors.
Plant Physiology and Biochemistry | Year: 2013

Grapevine (Vitis vinifera L.) is rich in phenylpropanoid compounds, namely flavonoids and stilbenes which, present in most tissues, are described as antioxidants and known to accumulate in response to biotic and abiotic stress. Grapevine is then a choice model for studying the interplay between the phenylpropanoid pathway and nutrient deficiency. Here we report the response to sulfur deficiency (-S) of flavonoids and stilbenes biosynthetic pathways in chlorophyll tissues (plantlets) and cell culture. Anthocyanins and trans-resveratrol accumulated in plantlets and trans-resveratrol glucoside in cell cultures in response to sulfur deficiency, while a significant decrease in chlorophyll was observed in -S plantlets. The up-regulation of chalcone synthase gene and the downstream flavonoid biosynthesis genes dihydroflavonol reductase and anthocyanidin synthase matched the accumulation of anthocyanins in -S V. vinifera plantlets. The mRNA level of stilbene synthase gene(s) was correlated tightly with the increase in trans-resveratrol and trans-resveratrol glucoside levels, respectively in -S plantlets and cell cultures. As a whole, the present study unveil that V. vinifera under sulfur deficiency allocates resources to the phenylpropanoid pathway, probably consecutive to inhibition of protein synthesis, which can be advantageous to resist against oxidative stress symptoms evoked by -S conditions. © 2013 Elsevier Masson SAS. Source

Silva S.,IBET | Boross P.,ITQB | Soares R.,ITQB | Coelho A.V.,ITQB | And 3 more authors.
Acta Horticulturae | Year: 2012

Matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry was used to study extracts of olive seeds at different maturation stages of fruits collected in the years 2009 and 2010. For comparison purposes LC-DAD-MS/MS assays were also done. Both methodologies confirmed the presence in olive seeds of secoiridoid compounds with higher molecular mass than nüzhenide 11-methyl-oleoside such as nüzhenide di and tri (11-methyl-oleosides). 11-methyloleoside glucosides derivatives such as hexa, penta and tetra derivatives were detected in seeds of mature fruits of the year 2009 suggesting a relationship of these compounds with olives maturation stage. Source

Henriques B.J.,ITQB | Olsen R.K.,Aarhus University Hospital | Bross P.,Aarhus University Hospital | Gomes C.M.,ITQB
Current Medicinal Chemistry | Year: 2010

Riboflavin, commonly known as vitamin B2, is the precursor of flavin cofactors. It is present in our typical diet, and inside the cells it is metabolized to FMN and FAD. As a result of their rather unique and flexible chemical properties these flavins are among the most important redox cofactors present in a large series of different enzymes. A problem in riboflavin metabolism or a low intake of this vitamin will have consequences on the level of FAD and FMN in the cell, resulting in disorders associated with riboflavin deficiency. In a few number of cases, riboflavin deficiency is associated with impaired oxidative folding, cell damage and impaired heme biosynthesis. More relevant are several studies referring reduced activity of enzymes such as dehydrogenases involved in oxidative reactions, respiratory complexes and enzymes from the fatty acid β-oxidation pathway. The role of this vitamin in mitochondrial metabolism, and in particular in fatty acid oxidation, will be discussed in this review. The basic aspects concerning riboflavin and flavin metabolism and deficiency will be addressed, as well as an overview of the role of the different flavoenzymes and flavin chemistry in fatty acid β-oxidation, merging clinical, cellular and biochemical perspectives. A number of recent studies shedding new light on the cellular processes and biological effects of riboflavin supplementation in metabolic disease will also be overviewed. Overall, a deeper understanding of these emerging roles of riboflavin intake is essential to design better therapies. © 2010 Bentham Science Publishers Ltd. Source

Courtois B.,CIRAD - Agricultural Research for Development | Greco R.,Parco Technologico Padano | Bruschi G.,Parco Technologico Padano | Frouin J.,CIRAD - Agricultural Research for Development | And 11 more authors.
Plant Genetic Resources: Characterisation and Utilisation | Year: 2011

In South Europe, rice is grown as an irrigated crop in river deltas where it plays an important role in soil desalinization. Specific varieties are needed for these tough conditions. We analyzed the genetic structure of a set of 305 varieties coming from the European Rice Germplasm Collection (ERGC) with 90 single nucleotide polymorphisms and compared it with a reference set representative of the diversity of Oryza sativa (mini-Germplasm Bank (GB)). These accessions had been characterized for their grain type and growth cycle duration. The polymorphism information contents of the ERGC were lower than those of the mini-GB, indicating a narrower genetic basis. Indeed, almost all ERGC accessions belong to the japonica group. Within the japonica group, both a dendrogram and a Bayesian clustering identified two major clusters. The first cluster encompassed tropical japonicas and American varieties from USA and Argentina characterized by long and narrow grains and medium to long duration. On a finer level, tropical japonicas appear separated from the other accessions. The second cluster is composed of European varieties mostly early or medium in duration and Asian temperate accessions, with a subgrouping based on grain format. A set of 200 accessions was composed for association mapping studies on traits such as salt tolerance. © 2011 NIAB. Source

Rodrigues Ribeiro R.S.,INESC Porto | Queiros R.B.,INESC Porto | Ecoffet C.,CNRS Mulhouse Institute of Materials Science | Soppera O.,CNRS Mulhouse Institute of Materials Science | And 3 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

This work reports a new type of optical fiber tweezers based on polymeric micro-lenses. The lenses are achieved by means of an economical and fast fabrication process, using an in-fiber photo-polymerization technique. The polymerization radiation is guided towards the fiber tip creating a polymeric waveguide. The method allows tailoring the geometry of the tip by adjusting the fabrication parameters. Furthermore, more complex shapes can be fabricated by exploring modal effects at the polymerization/trapping wavelengths, which can be used for different applications such as trapping, beam shaping and patterned illumination. © 2014 SPIE. Source

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