Time filter

Source Type

Rosas-Perez T.,National Autonomous University of Mexico | Rosenblueth M.,National Autonomous University of Mexico | Rincon-Rosales R.,Instituto Tecnologico de Tuxtla Gutierrez | Mora J.,National Autonomous University of Mexico | Martinez-Romero E.,National Autonomous University of Mexico
Genome Biology and Evolution | Year: 2014

Scale insects (Hemiptera: Coccoidae) constitute a very diverse group of sap-feeding insects with a large diversity of symbiotic associations with bacteria. Here, we present the complete genome sequence, metabolic reconstruction, and comparative genomics of the flavobacterial endosymbiont of the giant scale insect Llaveia axin axin. The gene repertoire of its 309,299 bp genome was similar to that of other flavobacterial insect endosymbionts though not syntenic. According to its genetic content, essential amino acid biosynthesis is likely to be the flavobacterial endosymbiont's principal contribution to the symbiotic association with its insect host. We also report the presence of a γ-proteobacterial symbiont that may be involved in waste nitrogen recycling and also has amino acid biosynthetic capabilities that may provide metabolic precursors to the flavobacterial endosymbiont. We propose "Candidatus Walczuchella monophlebidarum" as the name of the flavobacterial endosymbiont of insects from the Monophlebidae family. © The Author(s) 2014. Source

Ruiz-Valdiviezo V.M.,CINVESTAV | Luna-Guido M.,CINVESTAV | Galzy A.,Avenue Of Luniversite Bp 8 | Gutierrez-Miceli F.A.,Instituto Tecnologico de Tuxtla Gutierrez | Dendooven L.,CINVESTAV
Applied Soil Ecology | Year: 2010

Jatropha curcas L. will be cultivated in large parts of the central highlands of Chiapas (México) so that its seeds can be extracted for biofuel. Little is known how the cultivation of J. curcas, which contains phorbolesters, might affect soil processes. Soil was sampled at five locations and amended with leaves of J. curcas while dynamics of ammonium (NH4+), nitrite (NO2-) and nitrate (NO3-) and emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), well known greenhouse gasses, were monitored. If we considered no priming effect, then between 12 and 31% of the C added with Jatropha leaves mineralized within 56 days. However, the concentration of mineral N (sum of NH4+, NO2- and NO3-) did not increase in the Jatropha-amended soils compared to the unamended soils. The mean CO2 emission rate increased significantly 3.7 times when Jatropha leaves were added to the different soils. The N2O emission was low in the unamended soil and remained <5μgN2O-Nkg-1. Application of J. curcas leaves increased the N2O emission rate significantly in two soils, but not in the other three. Oxidation of CH4 occurred in each of the unamended soils with the fastest decrease generally found within the first day. Application of Jatropha leaves had no significant effect on oxidation of CH4, except in one soil. It was found that application of Jatropha leaves did increase emission of CO2, did not affect the soil mineral N content and had only an increasing effect on emission of N2O and oxidation of CH4 in some soils. © 2010 Elsevier B.V. Source

Ovando-Chacon G.E.,Instituto Tecnologico De Veracruz | Ovando-Chacon S.L.,Instituto Tecnologico de Tuxtla Gutierrez | Prince-Avelino J.C.,Instituto Tecnologico De Veracruz
International Journal of Heat and Mass Transfer | Year: 2012

Entropy generation due to steady state heat transfer and the motion of the vertical boundaries in a two-dimensional square cavity is numerically studied, using the value of the velocity and temperature obtained by solving the Navier-Stokes equation coupled with the energy equation with the finite element method and an operator splitting scheme. Increasing the Richardson number, the entropy generation by fluid friction is intensified inside the cavity due to the vortex formation at the central part of the cavity. The entropy generation by heat transfer becomes more intense at the vertical walls and the central low part of the cavity due to the stronger temperature gradients at this region. © 2011 Elsevier Ltd. All rights reserved. Source

Montero-Vargas J.M.,CINVESTAV | Gonzalez-Gonzalez L.H.,Instituto Tecnologico de Tuxtla Gutierrez | Galvez-Ponce E.,Agroindustrias Unidas de Mexico S.A. de C.V. AMSA | Ramirez-Chavez E.,CINVESTAV | And 4 more authors.
Molecular BioSystems | Year: 2013

High-throughput metabolic phenotyping is a challenge, but it provides an alternative and comprehensive access to the rapid and accurate characterization of plants. In addition to the technical issues of obtaining quantitative data of plenty of metabolic traits from numerous samples, a suitable data processing and statistical evaluation strategy must be developed. We present a simple, robust and highly scalable strategy for the comparison of multiple chemical profiles from coffee and tea leaf extracts, based on direct-injection electrospray mass spectrometry (DIESI-MS) and hierarchical cluster analysis (HCA). More than 3500 individual Coffea canephora and Coffea arabica trees from experimental fields in Mexico were sampled and processed using this method. Our strategy permits the classification of trees according to their metabolic fingerprints and the screening for families with desired characteristics, such as extraordinarily high or low caffeine content in their leaves. © 2013 The Royal Society of Chemistry. Source

Ovando-Chacon G.E.,Instituto Tecnologico De Veracruz | Ovando-Chacon S.L.,Instituto Tecnologico de Tuxtla Gutierrez | Prince-Avelino J.C.,Instituto Tecnologico De Veracruz | Romo-Medina M.A.,Instituto Tecnologico De Veracruz
European Journal of Mechanics, B/Fluids | Year: 2013

The steady vortex formation and thermal behavior in a two-dimensional square ventilated cavity is numerically studied. The governing equations of mass, momentum and energy are solved with a finite element method combined with an operator splitting scheme. We analyze the flow occurring inside the enclosure with a centered circular obstruction and a heater plate located at the center of the lower wall of the cavity. The size of the heater is varied for five different lengths. The simulations are obtained for Richardson and Prandtl numbers of 0.01 to 10.0 with a Reynolds number of 400. Results are reported in the form of streamlines, isotherms, average Nusselt number, average bulk fluid and obstruction temperatures. The effects of the heater length, Richardson number and Prandtl number on the hydrodynamics and thermal behavior have been investigated. Four vortex formation mechanisms are identified: (a) the inertial effect of the inlet jet which moves from the lower left sidewall to the upper right sidewall, (b) the detachment of the boundary layer from the wall located above of the entrance of the cavity and from the obstruction, (c) the rolling up of the fluid when this meets with the corners of the cavity and (d) the thermal boundary layer formed on the heater which originates a thermal plume with instabilities traveling upward. It is observed that for low Prandtl numbers with large heater sizes and high Richardson numbers the temperature of the obstruction is increased. © 2013 Elsevier Masson SAS. All rights reserved. Source

Discover hidden collaborations