Georgiev M.I.,Bulgarian Academy of Science |
Georgiev M.I.,Leiden University |
Agostini E.,National University of Rio Cuarto |
Ludwig-Muller J.,TU Dresden |
Xu J.,Arkansas State University
Trends in Biotechnology | Year: 2012
Hairy root syndrome is a disease that is induced by Agrobacterium rhizogenes infection and characterized by a proliferation of excessively branching roots. However, in the past 30 years A. rhizogenes-mediated transformation has also provided a valuable platform for studying biosynthesis pathways in plants. Furthermore, the genetically transformed root cultures are becoming increasingly attractive, cost-effective options for mass-producing desired plant metabolites and expressing foreign proteins. Numerous proof-of-concept studies have demonstrated the feasibility of scaling up hairy-root-based processes while maintaining their biosynthetic potential. Recently, hairy roots have also shown immense potential for applications in phytoremediation, that is, plant-based decontamination of polluted environments. This review highlights recent progress and limitations in the field, and outlines future perspectives for the industrial exploitation of hairy roots. © 2012 Elsevier Ltd.
Oggier G.G.,National University of Rio Cuarto |
Ordonez M.,University of British Columbia |
Galvez J.M.,University of British Columbia |
Luchino F.,Simon Fraser University
IEEE Transactions on Power Electronics | Year: 2014
This paper presents a boundary control scheme for dual active bridge (DAB) converters using the natural switching surface (NSS). The implementation of a curved switching surface for DAB converters is a new area of research undertaken in this paper. The proposed technique brings the benefit of unprecedented dynamic performance, already developed for nonisolated topologies (e.g., buck and boost), to this more complex isolated topology. The analysis provides insight into the natural trajectories of the DAB converters and creates an accurate framework in the normalized geometrical domain. As a result, the physical limits of the converter under study become evident. Those physical limits are exploited by employing the NSS to obtain fast transient response under start-up, sudden load transients, and reference change. In addition, fixed-frequency operation is one of the key features of the proposed control scheme, which allows optimizing the design of the high-frequency transformer. Experimental results are presented to validate the NSS for DAB converters and illustrate the benefits of the normalization technique. © 1986-2012 IEEE.
Otamendi J.E.,National University of Rio Cuarto |
Ducea M.N.,University of Arizona |
Bergantz G.W.,University of Washington
Journal of Petrology | Year: 2012
The petrogenesis of calc-alkaline magmatism in the Famatinian arc is investigated in the central Sierra Valle Fértil, a major, lower to middle crustal section of the Early Ordovician active margin of West Gondwana. Large-scale field relationships show a gradual and continuous compositional variation of the plutonic sequence, ranging from olivine-bearing gabbronorites to hornblende- and biotite-bearing granodiorites. Distinctive lithostratigraphic units are, however, discernible as one compositional type of plutonic rock dominates over mappable areas. These results allow us to identify a continuous plutonic arc stratigraphy that progressively exposes shallower paleo-depths towards the east. At all the exposed levels, calc-alkaline plutonic rocks are volumetrically dominant, interrupted only by granulite-facies migmatites and leucogranites. The migmatites are interpreted to be refractory remnants of supracrustal sedimentary successions, whereas the peraluminous leucogranites have field relationships and chemical and isotopic compositions suggesting that they were produced via anatexis of metasedimentary packages. Mass-balance calculations predict that a parental gabbroic magma after progressive closed-system fractionation would crystallize about 80% of the original mass to yield a granodioritic daughter. Because the crystallizing mineral assemblage comprises hornblende and plagioclase, mass balance suggests a volume of residual amphibole-rich gabbroic rocks much larger than that observed, suggesting that differentiation is significantly driven by open-system processes. Indeed, the combination of field and petrographic observations with bulk-rock geochemistry and petrogenetic modeling demonstrates that most dioritic and tonalitic rocks are hybrids formed by either (1) bulk assimilation of metasedimentary materials into gabbroic magmas, or (2) multi-stage and complex interactions between gabbroic rocks and metasedimentary-derived leucogranitic melts. The source region of the granodioritic magmas is located at the transition zone between a tonalite-dominated intermediate unit and a granodiorite-dominated silicic unit. Typical granodiorites have a hornblende-bearing mineralogy, metaluminous chemical signature and isotopic compositions [ 87Sr/ 86Sr(T) = 0·7075-0·7100 and ε Nd(T) ~ -5·0] broadly overlapping those of the tonalites of the intermediate rock unit. These major compositional features of the granodiorites can be best explained if three end-member components contribute to their generation. As field observational data suggest, primitive gabbroic rocks, metaluminous intermediate magmas and anatectic leucogranitic melts mixed to produce the calc-alkaline granodiorites; however, the exact petrological process generating the granodioritic magmas is unclear because the mafic end-member may have been incorporated as mafic inclusions in the intermediate magmas or as syn-magmatic dikes, or both. The polygenetic nature of the intermediate to silicic plutonic rocks, along with the preponderance of parental gabbroic rocks at the inferred base of the plutonic column, suggests an upward growth of the intermediate to silicic crust that involved the complete reconstitution of the pre-existing crustal configuration. The main implication of this study is that intermediate and silicic plutonic rocks in the Valle Fértil section formed within a crustal column in which the mass transfer and heat input of mantle-derived magmas promoted fusion of fertile metasedimentary rocks and favored mixing of gabbroic or dioritic magmas with crustal granitic melts. Our results lend support to models asserting that the thermal and material budget of arc magmatism is primarily governed by the rate at which mafic magmas ascend from their mantle sources and intrude repeatedly into the crust. © The Author 2012. Published by Oxford University Press. All rights reserved.
Demkura P.V.,CONICET |
Abdala G.,National University of Rio Cuarto |
Baldwin I.T.,Max Planck Institute for Chemical Ecology |
Plant Physiology | Year: 2010
Ultraviolet B (UV-B) radiation, a very small fraction of the daylight spectrum, elicits changes in plant secondary metabolism that have large effects on plant-insect interactions. The signal transduction pathways that mediate these specific effects of solar UV-B are not known. We examined the role of jasmonate signaling by measuring responses to UV-B in wild-type and transgenic jasmonate-deficient Nicotiana attenuata plants in which a lipoxygenase gene (NaLOX3) was silenced (as-lox). In wild-type plants, UV-B failed to elicit the accumulation of jasmonic acid (JA) or the bioactive JA-isoleucine conjugate but amplified the response of jasmonate-inducible genes, such as trypsin proteinase inhibitor (TPI), to wounding and methyl jasmonate, and increased the accumulation of several phenylpropanoid derivatives. Some of these phenolic responses (accumulation of caffeoyl-polyamine conjugates) were completely lacking in as-lox plants, whereas others (accumulation of rutin and chlorogenic acid) were similar in both genotypes. In open field conditions, as-lox plants received more insect damage than wild-type plants, as expected, but the dramatic increase in resistance to herbivory elicited by UV-B exposure, which was highly significant in wild-type plants, did not occur in as-lox plants. We conclude that solar UV-B (1) uses jasmonate-dependent and -independent pathways in the elicitation of phenolic compounds, and (2) increases sensitivity to jasmonates, leading to enhanced expression of wound-response genes (TPI). The lack of UV-B-induced antiherbivore protection in as-lox plants suggests that jasmonate signaling plays a central role in the mechanisms by which solar UV-B increases resistance to insect herbivores in the field. © 2009 American Society of Plant Biologists.
Agency: Cordis | Branch: H2020 | Program: RIA | Phase: SFS-13-2015 | Award Amount: 6.43M | Year: 2016
MycoKey aims to generate innovative and integrated solutions that will support stakeholders in effective and sustainable mycotoxin management along food and feed chains. The project will contribute to reduce mycotoxin contamination mainly in Europe and China, where frequent and severe mycotoxin contaminations occur in crops, and where international trade of commodities and contaminated batches are increasing. MycoKey will address the major affected crops maize, wheat and barley, their associated toxigenic fungi and related mycotoxins (aflatoxins, deoxynivalenol, zearalenone, ochratoxin A, fumonisins). The project will integrate key information and practical solutions for mycotoxin management into a smart ICT tool (MycoKey App), providing answers to stakeholders, who require rapid, customized forecasting, descriptive information on contamination risk/levels, decision support and practical economically-sound suggestions for intervention. Tools and methodologies will be strategically targeted for cost-effective application in the field and during storage, processing and transportation. Alternative and safe ways to use contaminated batches will be also delivered. The focus of Mycokey will be: i) innovating communications of mycotoxin management by applying ICT, providing input for legislation, enhancing knowledge and networks; ii) selecting and improving a range of tools for mycotoxin monitoring; iii) assessing the use of reliable solutions, sustainable compounds/green technologies in prevention, intervention and remediation. The multi-disciplinary consortium, composed by scientific, industrial and association partners (32), includes 11 Chinese institutions and will conduct the 4 years programme in a framework of international networks.