Entity

Time filter

Source Type


Background:Crassostrea gigas accumulates paralytic shellfish toxins (PST) associated with red tide species as Gymnodinium catenatum. Previous studies demonstrated bivalves show variable feeding responses to toxic algae at physiological level; recently, only one study has reported biochemical changes in the transcript level of the genes involved in C. gigas stress response.Principal Findings:We found that 24 h feeding on toxic dinoflagellate cells (acute exposure) induced a significant decrease in clearance rate and expression level changes of the genes involved in antioxidant defense (copper/zinc superoxide dismutase, Cu/Zn-SOD), cell detoxification (glutathione S-transferase, GST and cytochrome P450, CPY450), intermediate immune response activation (lipopolysaccharide and beta glucan binding protein, LGBP), and stress responses (glutamine synthetase, GS) in Pacific oysters compared to the effects with the non-toxic microalga Isochrysis galbana. A sub-chronic exposure feeding on toxic dinoflagellate cells for seven and fourteen days (30×103 cells mL-1) showed higher gene expression levels. A significant increase was observed in Cu/Zn-SOD, GST, and LGBP at day 7 and a major increase in GS and CPY450 at day 14. We also observed that oysters fed only with G. catenatum (3×103 cells mL-1) produced a significant increase on the transcription level than in a mixed diet (3×103 cells mL-1 of G. catenatum+0.75×106 cells mL-1 I. galbana) in all the analyzed genes.Conclusions:Our results provide gene expression data of PST producer dinoflagellate G. catenatum toxic effects on C. gigas, a commercially important bivalve. Over expressed genes indicate the activation of a potent protective mechanism, whose response depends on both cell concentration and exposure time against these toxic microalgae. Given the importance of dinoflagellate blooms in coastal environments, these results provide a more comprehensive overview of how oysters respond to stress generated by toxic dinoflagellate exposure. © 2013 García-Lagunas et al. Source


Martinez-Diaz S.,Technological Institute of La Paz | Martinez-Chavelas S.,National Autonomous University of Mexico
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2014

Geometrical distortions are a major problem in image recognition. Composite correlation filters can be used for distortion-invariant image recognition by incorporating rotated versions of the target object. Traditionally composite filters are designed with linear techniques; but, these filters are sensitive to non-Gaussian noise. On the other hand, for the same purpose, composite nonlinear filters have been proposed too. These filters have a good discrimination capability and they are robust to non-Gaussian noise and illumination changes; however, the performance of filter could be reduced when the number of training images incorporated increases. In this paper, we propose a method for designing rotation-invariant composite nonlinear filters. The method tries to maximize the number of objects incorporated into the filter and preserve its performance. © Springer International Publishing Switzerland 2014. Source


De-Leon Almaraz S.,R.A.U.M. | Azzaro-Pantel C.,R.A.U.M. | Montastruc L.,R.A.U.M. | Pibouleau L.,R.A.U.M. | Senties O.B.,Technological Institute of La Paz
Computer Aided Chemical Engineering | Year: 2012

his work presents a methodology for the introduction of new criteria in a mathematical formulation dedicated to hydrogen supply chains (HSC). The optimisation approach of Almansoori and Shah [1] has been extended to develop a multiobjective design in which not only the total daily cost of the network but also its environmental and safety impacts have been considered. Results of mono and multicriteria optimisations are compared and discussed in order to highlight the main differences between both approaches. © 2012 Elsevier B.V. Source


Martinez-Diaz S.,Technological Institute of La Paz
Lecture Notes in Electrical Engineering | Year: 2013

Recently, nonlinear composite correlation filters have been proposed for distortion-invariant pattern recognition. The filter design is based on logical operations and the correlation is computed with a nonlinear operation called morphological correlation. In this paper a new implementation in parallel hardware of these kinds of filters for image recognition is proposed. The architecture is designed for a Field Programmable Gate Array (FPGA) device. The proposed design performs the most time consuming task of the recognition procedure. In consequence, it reduces the time required for the nonlinear operations in the spatial domain. Simulation results are provided and discussed. © 2013 Springer Science+Business Media Dordrecht. Source


Figueroa-Valverde L.,A.P.S. University | Diaz-Cedillo F.,National Polytechnic Institute of Mexico | Garcia-Cervera E.,A.P.S. University | Pool Gomez E.,A.P.S. University | And 3 more authors.
Archives of Pharmacal Research | Year: 2013

Experimental studies indicate that some steroid derivatives have inotropic activity; nevertheless, there is scarce information about the effects of the dehydroisoandrosterone and its derivatives at cardiovascular level. In addition, to date the cellular site and mechanism of action of dehydroisoandrosterone at cardiovascular level is very confusing. In order, to clarify those phenomena in this study, a dehydroisoandrosterone derivative was synthesized with the objective of to evaluate its activity on perfusion pressure and coronary resistance and compare this phenomenon with the effect exerted by dehydroisoandrosterone. The Langendorff technique was used to measure changes on perfusion pressure and coronary resistance in an isolated rat heart model in absence or presence of dehydroisoandrosterone and its derivative. Additionally, to characterize the molecular mechanism involved in the inotropic activity induced by dehydroisoandrosterone derivative was evaluated by measuring left ventricular pressure in absence or presence of following compounds; flutamide, prazosin, metoprolol and nifedipine. The results showed that dehydroisoandrosterone derivative significantly increased the perfusion pressure and coronary resistance in comparison with the control conditions and dehydroisoandrosterone. Additionally, other data indicate that dehydroisoandrosterone derivative increase left ventricular pressure in a dose-dependent manner [1 × 10-9-1 × 10-4 mmol]; nevertheless, this phenomenon was significantly inhibited by nifedipine at a dose of 1 × 10-6 mmol. In conclusion, these data suggest that dehydroisoandrosterone derivative induces positive inotropic activity through of activation the L-type calcium channel. © 2013 The Pharmaceutical Society of Korea. Source

Discover hidden collaborations