Instituto Polite cnico Nacional

Mexico City, Mexico

Instituto Polite cnico Nacional

Mexico City, Mexico
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Ruiz-Medrano R.,Instituto Polite Cnico Nacional | Xoconostle-Cazares B.,Instituto Polite Cnico Nacional | Ham B.-K.,University of California at Davis | Li G.,University of California at Davis | Lucas W.J.,University of California at Davis
Plant Journal | Year: 2011

Phloem-transported signals play an important role in regulating plant development and in orchestrating responses to environmental stimuli. Among such signals, phloem-mobile RNAs have been shown to play an important role as long-distance signaling agents. At maturity, angiosperm sieve elements are enucleate, and thus transcripts in the phloem translocation stream probably originate from the nucleate companion cells. In the present study, a pumpkin (Cucurbita maxima) phloem transcriptome was used to test for the presence of common motifs within the promoters of this unique set of genes, which may function to coordinate expression in cells of the vascular system. A bioinformatics analysis of the upstream sequences from 150 Arabidopsis genes homologous to members of the pumpkin phloem transcriptome identified degenerate sequences containing CT/GA- and GT/CA-rich motifs that were common to many of these promoters. Parallel studies performed on genes shown previously to be expressed in phloem tissues identified similar motifs. An expanded analysis, based on homologs of the pumpkin phloem transcriptome from cucumber (Cucumis sativus), identified similar sets of common motifs within the promoters of these genes. Promoter analysis offered support for the hypothesis that these motifs regulate expression within the vascular system. Our findings are discussed in terms of a role for these motifs in coordinating gene expression within the companion cell/sieve element system. These motifs could provide a useful bioinformatics tool for genome-wide screens on plants for which phloem tissues cannot readily be obtained. © 2011 Blackwell Publishing Ltd.

Chang Y.L.,China Agricultural University | Yu Wang J.,China Agricultural University | Tao Wang E.,Instituto Polite cnico Nacional | Can Liu H.,CAS Institute of Microbiology | And 2 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2011

Five strains isolated from root nodules of Lablab purpureus and Arachis hypogaea grown in the Anhui and Sichuan provinces of China were classified as members of the genus Bradyrhizobium. These strains had identical 16S rRNA gene sequences which shared 99.48%, 99.48% and 99.22% similarity with the most closely related strains of Bradyrhizobium jicamae PAC68 T, Bradyrhizobium pachyrhizi PAC48T and Bradyrhizobium elkanii USDA 76 T, respectively. A study using a polyphasic approach, including 16S rRNA gene RFLP, IGS-RFLP, BOX-PCR, comparative sequence analysis of the 16S-23S rRNA intergenic spacer (IGS) and the recA, atpD and glnII genes, DNA-DNA hybridization and phenotypic tests, showed that the five strains clustered into a coherent group that differentiated them from all recognized species of the genus Bradyrhizobium. Sequencing of nifH and nodC genes and cross-nodulation tests showed that the representative strains CCBAU 23086 T, CCBAU 23160 and CCBAU 61434, isolated from different plants, had identical nifH and nodC gene sequences and were all able to nodulate Lablab purpureus, Arachis hypogaea and Vigna unguiculata. Based upon these results, the name Bradyrhizobium lablabi sp. nov. is proposed for this novel species and strain CCBAU 23086 T (5LMG 25572T5HAMBI 3052 T) is designated as the type strain. The DNA G+C mol% is 60.14 (T m). © 2011 IUMS.

Zheng W.T.,China Agricultural University | Li Jr. Y.,China Agricultural University | Wang R.,China Agricultural University | Sui X.H.,China Agricultural University | And 5 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2013

In a study on the diversity of rhizobia isolated from root nodules of Astragalus sinicus, five strains showed identical 16S rRNA gene sequences. They were related most closely to the type strains of Mesorhizobium loti, Mesorhizobium shangrilense, Mesorhizobium ciceri and Mesorhizobium australicum, with sequence similarities of 99.6-99.8 %. A polyphasic approach, including 16S- 23S intergenic spacer (IGS) RFLP, comparative sequence analysis of 16S rRNA, atpD, glnII and recA genes, DNA-DNA hybridization and phenotypic tests, clustered the five isolates into a coherent group distinct from all recognized Mesorhizobium species. Except for strain CCBAU 33446, from which no symbiotic gene was detected, the four remaining strains shared identical nifH and nodC gene sequences and nodulated with Astragalus sinicus. In addition, these five strains showed similar but different fingerprints in IGS-RFLP and BOX-repeat-based PCR, indicating that they were not clones of the same strain. They were also distinguished from recognized Mesorhizobium species by several phenotypic features and fatty acid profiles. Based upon all the results, we suggest that the five strains represent a novel species for which the name Mesorhizobium qingshengii sp. nov. is proposed. The type strain is CCBAU 33460T (=CGMCC 1.12097T=LMG 26793T=HAMBI 3277T). The DNA G+C content of the type strain is 59.52 mol% (Tm). © 2013 IUMS.

Zhang Y.M.,China Agricultural University | Li Jr. Y.,China Agricultural University | Chen W.F.,China Agricultural University | Wang E.T.,China Agricultural University | And 6 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2012

In a survey of the biodiversity and biogeography of rhizobia associated with soybean (Glycine max L.) in different sites of the Northern (Huang-Huai-Hai) Plain of China, ten strains were defined as representing a novel genomic species in the genus of Bradyrhizobium. They were distinguished from defined species in restriction fragment length polymorphism (RFLP) analysis of the 16S rRNA gene and the 16S-23S rRNA gene intergenic spacer (IGS). In BOX-PCR, these strains presented two patterns that shared 94% similarity, demonstrating that they were a homogenous group with limited diversity. In phylogenetic analyses of the 16S rRNA gene, IGS and housekeeping gene sequences, four representative strains formed a distant lineage within the genus Bradyrhizobium, which was consistent with the results of DNA-DNA hybridization. The strains of this novel group formed effective nodules with G. max, Glycine soja and Vigna unguiculata in cross-nodulation tests and harboured symbiotic genes (nodC and nifH) identical to those of reference strains of Bradyrhizobium japonicum, Bradyrhizobium liaoningense and 'Bradyrhizobium daqingense' originating from soybean, implying that the novel group may have obtained these symbiotic genes by lateral gene transfer. In analyses of cellular fatty acids and phenotypic features, some differences were found between the novel group and related Bradyrhizobium species, demonstrating that the novel group is distinct phenotypically from other Bradyrhizobium species. Based upon the data obtained, these strains are proposed to represent a novel species, Bradyrhizobium huanghuaihaiense sp. nov., with CCBAU 23303T (=LMG 26136T =CGMCC 1.10948T =HAMBI 3180T) as the type strain. The DNA G+C content of strain CCBAU 23303T is 61.5 mol% (Tm). © 2012 IUMS.

Zhao C.T.,China Agricultural University | Zhao C.T.,Zhejiang University of Technology | Wang E.T.,Instituto Polite cnico Nacional | Zhang Y.M.,China Agricultural University | And 5 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2012

Four rhizobial strains representing a previously defined novel group in the genus Mesorhizobium and isolated from Astragalus species in China were further characterized using a polyphasic approach. Phylogenetic analysis of 16S rRNA gene sequences showed that these Gram-negative bacteria belonged to the genus Mesorhizobium, with Mesorhizobium plurifarium LMG 11892T as the closest neighbour sharing a sequence similarity of 99.8 %. Comparative sequence analysis of the atpD, recA, glnII, rpoB, nodC and nifH genes, SDS-PAGE of whole-cell soluble proteins, DNA-DNA hybridization, fatty acid profiles and a series of phenotypic and physiological tests differentitated the novel group from all recognized species of the genus Mesorhizobium. Based on the data obtained in the present and previous studies, this group represents a novel species within the genus Mesorhizobium, for which the name Mesorhizobium silamurunense sp. nov. is proposed. The type strain is CCBAU 01550T (=HAMBI 3029T=LMG 24822T), and could form effective nodules on Astragalus membranaceus, Astragalus adsurgens and Caragana intermedia, and ineffective nodules on Phaseolus vulgaris in cross-nodulation tests. G 2012 IUMS.

Cordoba E.,National Autonomous University of Mexico | Porta H.,National Autonomous University of Mexico | Arroyo A.,National Autonomous University of Mexico | Arroyo A.,Instituto Polite Cnico Nacional | And 4 more authors.
Journal of Experimental Botany | Year: 2011

The 1-deoxy-D-xylulose 5-phosphate synthase (DXS) enzyme catalyses the first biosynthetic step of the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. In plants the MEP pathway is involved in the synthesis of the common precursors to the plastidic isoprenoids, isopentenyl diphosphate and dimethylallyl diphosphate, in plastids. DXS is recognized as limiting this pathway and is a potential target for manipulation to increase various isoprenoids such as carotenoids. In Zea mays three dxs genes exist that encode plastid-targeted functional enzymes. Evidence is provided that these genes represent phylogenetically distinctive clades conserved among plants preceding monocot-dicot divergence. There is differential accumulation for each dxs gene transcript, during development and in response to external signals such as light. At the protein level, the analysis demonstrates that in Z. mays, DXS protein is feedback regulated in response to the inhibition of the pathway flow. The results support that the multilevel regulation of DXS activity is conserved in evolution. © 2010 The Author(s).

Rodriguez-Avila N.L.,Research Center Cientifica Of Yucatan Ac Calle 43 No 130 | Narvaez-Zapata J.A.,Instituto Polite Cnico Nacional | Ramirez-Benitez J.E.,Research Center Cientifica Of Yucatan Ac Calle 43 No 130 | Aguilar-Espinosa M.L.,Research Center Cientifica Of Yucatan Ac Calle 43 No 130 | Rivera-Madrid R.,Research Center Cientifica Of Yucatan Ac Calle 43 No 130
Journal of Experimental Botany | Year: 2011

Carotenoid cleavage dioxygenases (CCDs) are a class of enzymes involved in the biosynthesis of a broad diversity of secondary metabolites known as apocarotenoids. In plants, CCDs are part of a genetic family with members which cleave specific double bonds of carotenoid molecules. CCDs are involved in the production of diverse and important metabolites such as vitamin A and abscisic acid (ABA). Bixa orellana L. is the main source of the natural pigment annatto or bixin, an apocarotenoid accumulated in large quantities in its seeds. Bixin biosynthesis has been studied and the involvement of a CCD has been confirmed in vitro. However, the CCD genes involved in the biosynthesis of the wide variety of apocarotenoids found in this plant have not been well documented. In this study, a new CCD1 gene member (BoCCD1) was identified and its expression was charaterized in different plant tissues of B. orellana plantlets and adult plants. The BoCCD1 sequence showed high homology with plant CCD1s involved mainly in the cleavage of carotenoids in several sites to generate multiple apocarotenoid products. Here, the expression profiles of the BoCCD1 gene were analysed and discussed in relation to total carotenoids and other important apocarotenoids such as bixin. © 2011 The Author.

Cordova-Albores L.C.,Instituto Polite cnico Nacional | Rios M.Y.,University of Central Mexico | Barrera-Necha L.L.,Instituto Polite cnico Nacional | Bautista-Banos S.,Instituto Polite cnico Nacional
Industrial Crops and Products | Year: 2014

Application of plant derivatives, including Jatropha curcas seed oil, is among the newest alternative methods for controlling Fusarium oxysporum f. sp. gladioli, one of the most widespread and destructive gladiolus fungi. Phorbol esters are considered the main toxic compounds in J. curcas seeds; therefore, knowing the amount of these compounds for the possible application of the oil as fungicide is of utmost importance, including the identification and evaluation of the fungicidal effect of its compounds. In this study, phorbol ester content in the seed oil of a native J. curcas species from the state of Chiapas, Mexico, was almost negligible (0.15mgg-1). The result of the fractionation indicates that triacylglycerides were the dominant lipids. Further methanolysis of J. curcas seed oil and its fractions gave 49% oleic acid. Antifungal assays showed that the seed oil of J. curcas at 2.5mgmL-1 inhibited the growth rate of F. oxysporum f. sp. gladioli to about 0.77cmday-1, while the effect of the G1-G9 fractions, obtained by column chromatography, tested on this parameter was variable. The best inhibitory concentration for G3-G9 fractions was 200mgL-1. In G4 fraction at a similar concentration, the lowest percentage germination (about 57%) was observed. From the active compounds and commercial triacylglycerides tested, no pattern was associated with concentration-inhibition in the growth rate assay, while the lowest percentage germination was with the commercial triolein at 500mgL-1 (30% approximately). © 2014 Elsevier B.V.

Torres-Torres C.,Instituto Polite Cnico Nacional
Nanotechnology | Year: 2015

Due to their selective and fascinating effects, metallic nanoparticles have become a very significant topic for science. A modification in morphology and structure of low-dimensional materials can result in extraordinary ultrafast physical phenomena. New findings related to electronic, optical and magnetic processes have emerged from surface plasmon resonance excitations in nanoparticles. Moreover, multi-functional systems can be obtained from the integration of different elements in a nanostructured configuration. Recently, Palmero et al (2015 Nanotechnology 26 461001) have reported magneto-optical Kerr effect explorations in individual FeCuCo nanowires; the influence of tailored morphologies exhibited by particular samples was analyzed. An important magnetization reversal action was revealed and it was concluded that the demagnetization may be responsible for vortex domain wall propagation. The report can provide a solid base for future research and immediate applications in modern spintronics or magnetic data storage can be contemplated. © 2016 IOP Publishing Ltd.

Lo pez-Ortega A.,Instituto Polite cnico Nacional
Revista Mexicana de Fisica | Year: 2014

In a D-dimensional Lifshitz black hole we calculate exactly the quasinormal frequencies of a test Dirac field in the massless and zero angular eigenvalue limits. These results are an extension of the previous calculations in which the quasinormal frequencies of the Dirac field are determined, but in four dimensions. We discuss the four-dimensional limit of our expressions for the quasinormal frequencies and compare with the previous results. We also determine whether the Dirac field has unstable modes in the D-dimensional Lifshitz spacetime.

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