Papers by Eduardo Hernandez Altamirano
Plant and Soil, 2011
Plant growth promoting rhizobacteria (PGPR) stimulate plant growth and development by different m... more Plant growth promoting rhizobacteria (PGPR) stimulate plant growth and development by different mechanisms, including the production of different classes of signaling molecules, which may directly affect plant morphogenesis. Here, we report the effects of inoculation of Arthrobacter agilis UMCV2, a PGPR isolated from the rhizosphere of maize plants on growth and development of Medicago sativa seedlings. A. agilis UMCV2 inoculation promoted growth in M. sativa plants as revealed by increased stem length, root length and plant biomass. Inoculation of A. agilis using divided Petri plates decreased taproot growth and increased lateral root formation in plants grown in separate compartments suggesting a role of volatile organic compounds (VOCs) produced by this bacterium in root development. The analysis of VOCs produced by A. agilis UMCV2 identified N,N-dimethyl-hexadecanamine (dimethylhexadecylamine), an amino lipid structurally related to bacterial quorum-sensing signals, which modulated A. agilis UMCV2 growth and plant development in a dose-dependent way. Taken together, our results indicate that bacterial VOCs can be perceived by legume plants to modulate growth and morphogenetic processes and identify a novel signaling molecule potentially involved in plant-rhizobacterial interactions.
Designed Monomers and Polymers, 2007
We have prepared a series of carboxyalkyl methacrylates from the corresponding methoxy protected ... more We have prepared a series of carboxyalkyl methacrylates from the corresponding methoxy protected acids using pig liver esterase. From a set of these methacrylate derivatives with 3, 4, 5 and 7 methylenes as spacers, the enzymatic reaction exhibits a substrate selectivity for the terminal ester group of the molecule containing a short side-chain (3 methylenes); however, selectivity decreases as the
Research in Microbiology, 2009
The nitrogen-fixing bacteria commonly known as rhizobia are attractive organisms due to their sym... more The nitrogen-fixing bacteria commonly known as rhizobia are attractive organisms due to their symbiotic association with legume plants. Their genomes contain a large number of redundant genetic elements. These reiterations might participate in homologous recombination events and lead to diverse genomic rearrangements. Here we analyze the role of homologous recombination in the dynamics of these bacterial genomes, as well as its possible biological consequences.
American Journal of Medical Genetics, 1997
Non-insulin-dependent diabetes mellitus (NIDDM) is the most common form of diabetes, affecting 5%... more Non-insulin-dependent diabetes mellitus (NIDDM) is the most common form of diabetes, affecting 5% of the general population. Genetic factors play an important role in the development of the disease. While in other populations NIDDM is usually diagnosed after the fifth decade of life, in Mexico a large proportion of patients develop the disease at an early age (between the third and the fourth decade). In Caucasian population, mutations in the glucokinase gene, the TCF1, and TCF14 genes, have been identified in a subgroup of early-onset NIDDM patients denominated MODY (maturity-onset diabetes of the young), which show an autosomal dominant pattern of inheritance. As a first step in the molecular characterization of Mexican families displaying early-onset NIDDM we searched for mutations in the glucokinase gene through SSCP analysis and/or direct sequencing in 26 individuals from 22 independent families, where at least four can be classified as MODY. No mutations were detected in the exons or the intron-exon boundaries of the gene in any of the screened individuals. The phenotype and clinical profile of some of the studied patients is compatible with that of patients carrying mutations in the TCF1 or TCF14 genes, while others may carry mutations in different loci. Through computer simulation analysis we identified at least four informative families which will be used for further linkage studies.
Progress in Oceanography, 2007
The Gulf of California is unique because of its geographical location and conformation. It hosts ... more The Gulf of California is unique because of its geographical location and conformation. It hosts diverse ecosystems and important fisheries that support industry and provide livelihood to coastal settlements. It is also the site of interests and 0079-6611/$ -see front matter Ó problems, and an intense interaction among managers, producers, and conservationists. In this report, we scrutinize the abiotic (hydrography, climate, ocean circulation, and chemistry) and biotic (phyto-and zooplankton, fish, invertebrates, marine mammals, birds, and turtles) components of the marine ecosystem, and some particular aspects of climate variability, endemisms, harmful algal blooms, oxygen minimum layer, and pollution. We also review the current conditions and conflicts around the main fisheries (shrimp, small and large pelagic fishes, squid, artisanal and sportfishing), the most important human activity in the Gulf of California. We cover some aspects of management and conservation of fisheries, especially the claimed overexploitation of fish resources and the ecosystems, and review proposals for creating networks of marine protected areas. We conclude by identifying main needs for information and research, particularly the integration of data bases, the implementation of models and paleoreconstructions, establishment of monitoring programs, and the evaluation of fishing impacts and management actions.
Symbiosis, 2010
Extensive communication occurs between plants and microorganisms during different stages of plant... more Extensive communication occurs between plants and microorganisms during different stages of plant development in which signaling molecules from the two partners play an important role. Volatile organic compounds (VOCs) emission by certain plant-growth promoting rhizobacteria (PGPR) has been found to be involved in plant growth. However, little is known about the role of bacterial VOCs in plant developmental processes. In this work, we investigated the effects of inoculation with twelve bacterial strains isolated from the rhizosphere of lemon plants (Citrus aurantifolia) on growth and development of Arabidopsis thaliana seedlings. Several bacterial strains showed a plant growth promoting effect stimulating biomass production, which was related to differential modulation of root-system architecture. The isolates L263, L266, and L272a stimulated primary root growth and lateral root development, while L254, L265a and L265b did not significantly alter primary root growth but strongly promoted lateral root formation. VOC emission analysis by SPME-GC-MS identified aldehydes, ketones and alcohols as the most abundant compounds common to most rhizobacteria. Other VOCs, including 1-octen-3-ol and butyrolactone were strain specific. Characterization of L254, L266 and L272a bacterial isolates by 16S rDNA analysis revealed the identity of these strains as Bacillus cereus, Bacillus simplex and Bacillus sp, respectively. Taken together, our data suggest that rhizospheric bacterial strains can modulate both plant growth promotion and root-system architecture by differential VOC emission.
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Papers by Eduardo Hernandez Altamirano