Rafael Palacios

Universidad Nacional Autónoma de México

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

Margarita Flores

Universidad Nacional Autónoma de México

Guillermo Dávila

Lund University

David Romero

Universidad Nacional Autónoma de México

Susana Brom

Universidad Nacional Autónoma de México

Esperanza Martínez‐Romero

Universidad Nacional Autónoma de México

Carmen Quinto

Universidad Nacional Autónoma de México

Jaime Mora

Universidad Veracruzana

Robert Schimke

National Institutes of Health

Patrick Mavingui

Peuplements végétaux et bioagresseurs en milieu tropical

Víctor González

Universidad Nacional Autónoma de México

Cooperative Institutions

Universidad Nacional Autónoma de México

115

Universidad Autónoma del Estado de Morelos

Center for Genomic Science

Centre National de la Recherche Scientifique

Institut Pasteur

Stanford University

National Institute of Genomic Medicine

University of Göttingen

University of Geneva

Autonomous University of Queretaro

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Genomes and Genomics of Nitrogen-fixing Organisms

Springer eBooks (2005)

Rafael Palacios William E. Newton

10.1007/1-4020-3054-1

Cite

Citations (65)

Isolation of Hen Oviduct Ovalbumin and Rat Liver Albumin Polysomes by Indirect Immunoprecipitation

Journal of Biological Chemistry (1974)

David J. Shapiro John M. Taylor G. Stanley McKnight Rafael Palacios Carmen González

Abstract The polyribosomes synthesizing ovalbumin and albumin have been isolated from total oviduct polysomes and total rat liver polysomes, respectively. The isolation was performed using an indirect immunoprecipitation technique which is based on the specific reaction which occurs between antibody against a purified native protein and the nascent peptide chains on polysomes synthesizing that protein. A soluble antibody-nascent chain-polysome complex is formed by incubating antibody with polysomes, and then precipitated by reaction with an anti-antibody. The techniques developed are both efficient and highly specific. Near quantitative isolation of polysomal mRNA coding for a specific protein may be achieved. Indirect immunoprecipitation results in nonspecific precipitation of less than 0.5% of total polysomes. Ovalbumin mRNA isolated by indirect immunoprecipitation is 99% pure with respect to contamination by other species of mRNA and rat liver albumin mRNA is greater than 95% pure. Evidence supporting these conclusions includes: (a) incubation of oviduct polysomes containing labeled nascent peptide chains with anti-bovine serum albumin results in precipitation of only 0.4% of the labeled polysomes; (b) indirect immunoprecipitates from oviduct polysomes reacted with anti-ovalbumin contain essentially no nascent peptide chains larger than ovalbumin; (c) ovalbumin and albumin mRNAs extracted from immunoprecipitates are enriched for the synthesis of their respective proteins by 1.8- and 8.7-fold, exactly the degree of purification predicted from their relative rates of synthesis; (d) isolation of albumin synthesizing polysomes from a mixture of rat liver polysomes and hen oviduct polysomes resulted in nonspecific precipitation of only 0.4% of the ovalbumin synthesizing polysomes when the immunoprecipitated RNA was assayed for its ability to synthesize ovalbumin in vitro. Indirect immunoprecipitation appears to be a general method widely applicable to the separation and isolation of polysomes and messenger RNAs coding for specific proteins.

Polysome

Oviduct

Immunoprecipitation

Bovine serum albumin

10.1016/s0021-9258(19)42526-x

Cite

Citations (172)

Genetic structure of a soil population of nonsymbiotic Rhizobium leguminosarum

Applied and Environmental Microbiology (1991)

Lorenzo Segovia Daniel Piñero Rafael Palacios Esperanza Martínez‐Romero

The genetic structure of a population of nonsymbiotic Rhizobium leguminosarum strains was determined by the electrophoretic mobilities of eight metabolic enzymes. Nonsymbiotic strains were isolated from the rhizosphere of bean plants and characterized by growth on differential media and at different temperatures, intrinsic antibiotic resistance, the lack of homology to a nifH probe, and their inability to form nodules on bean roots. All the isolates clustered with R. leguminosarum bv. phaseoli reference strains and did not encompass any other Rhizobium taxa. Their rRNA operon restriction fragment length polymorphisms and the nucleotide sequence of a fragment of the 16S rRNA gene were also found to be identical to those of R. leguminosarum bv. phaseoli reference strains. When complemented with an R. leguminosarum bv. phaseoli symbiotic plasmid (p42d), the nonsymbiotic isolates were able to fix nitrogen in symbiosis with bean roots at levels similar to those of the parental strain. The symbiotic isolates were found at a relative frequency of 1 in 40 nonsymbiotic R. leguminosarum strains.

Rhizobium leguminosarum

10.1128/aem.57.2.426-433.1991

Cite

Citations (227)

Genome Structure of Diazotrophs

Current plant science and biotechnology in agriculture (2000)

Rafael Palacios Manuel Megı́as

10.1007/0-306-47615-0_144

Cite

Citations (0)

Rhizobium sp. Strain NGR234 Possesses a Remarkable Number of Secretion Systems

Applied and Environmental Microbiology (2009)

Christel Schmeisser Heiko Liesegang Dagmar Krysciak Nadia Bakkou Antoine Le Queré

Rhizobium sp. strain NGR234 is a unique alphaproteobacterium (order Rhizobiales) that forms nitrogen-fixing nodules with more legumes than any other microsymbiont. We report here that the 3.93-Mbp chromosome (cNGR234) encodes most functions required for cellular growth. Few essential functions are encoded on the 2.43-Mbp megaplasmid (pNGR234b), and none are present on the second 0.54-Mbp symbiotic plasmid (pNGR234a). Among many striking features, the 6.9-Mbp genome encodes more different secretion systems than any other known rhizobia and probably most known bacteria. Altogether, 132 genes and proteins are linked to secretory processes. Secretion systems identified include general and export pathways, a twin arginine translocase secretion system, six type I transporter genes, one functional and one putative type III system, three type IV attachment systems, and two putative type IV conjugation pili. Type V and VI transporters were not identified, however. NGR234 also carries genes and regulatory networks linked to the metabolism of a wide range of aromatic and nonaromatic compounds. In this way, NGR234 can quickly adapt to changing environmental stimuli in soils, rhizospheres, and plants. Finally, NGR234 carries at least six loci linked to the quenching of quorum-sensing signals, as well as one gene (ngrI) that possibly encodes a novel type of autoinducer I molecule.

10.1128/aem.00515-09

Cite

Citations (155)

Copy Number Variation

Elsevier eBooks (2022)

Rafael Palacios Claudia Gonzaga‐Jauregui Margarita Flores Kim Palacios-Flores

Structural Variation

Non-allelic homologous recombination

Variation (astronomy)

10.1016/b978-0-12-822563-9.00049-4

Cite

Citations (2)

STUDIES ON THE RELATIONSHIP BETWEEN GABA SYNTHESIS AND PROTEIN SYNTHESIS IN BRAIN

Journal of Neurochemistry (1976)

Maríaa‐Elena Sandoval Rafael Palacios Ricardo Tapia

Abstract— The synthesis of γ‐aminobutyric acid (GABA) in mouse brain was decreased by treatment of the animals with pyridoxal phosphate‐ γ‐glutamylhydrazone, an inhibitor of glutamate decarboxylase in vivo. Under these experimental conditions the following parameters were studied: (1) the incorporation of labeled leucine in vivo , into protein of brain subcellular fractions; (2) the brain polysome profile; (3) the incorporation of labeled leucine into protein in vitro , in ribosomal preparations isolated from brain tissue. In other experiments, GABA synthesis was also decreased in brain cortex slices by preincubation with aminooxyacetic acid. The incorporation of [ 3 H]leucine or [ 14 C]leucine into protein in these slices was studied, and samples from the proteins were subjected to acrylamide‐sodium dodecylsulfate gel electrophoresis. Radioactivity was counted in slices of the gel. The results of the experiments in vivo and in vitro indicate that the previously reported decrease of protein synthesis induced by an inhibition of GABA synthesis affects proteins of all subcellular fractions and all populations of protein as separated by gel electrophoresis. The polysome profile from brains of mice with decreased GABA synthesis was similar to that of control mice. This result differs from that found when brain protein synthesis is inhibited by dopamine and serotonin.

Aminooxyacetic acid

Pyridoxal phosphate

10.1111/j.1471-4159.1976.tb10392.x

Cite

Citations (9)

Conserved Symbiotic Plasmid DNA Sequences in the Multireplicon Pangenomic Structure of Rhizobium etli

Applied and Environmental Microbiology (2010)

Víctor González José Luís Acosta Rosa I. Santamaría Patricia Bustos José Luis Fernández

ABSTRACT Strains of the same bacterial species often show considerable genomic variation. To examine the extent of such variation in Rhizobium etli , the complete genome sequence of R. etli CIAT652 and the partial genomic sequences of six additional R. etli strains having different geographical origins were determined. The sequences were compared with each other and with the previously reported genome sequence of R. etli CFN42. DNA sequences common to all strains constituted the greater part of these genomes and were localized in both the chromosome and large plasmids. About 700 to 1,000 kb of DNA that did not match sequences of the complete genomes of strains CIAT652 and CFN42 was unique to each R. etli strain. These sequences were distributed throughout the chromosome as individual genes or chromosomal islands and in plasmids, and they encoded accessory functions, such as transport of sugars and amino acids, or secondary metabolism; they also included mobile elements and hypothetical genes. Sequences corresponding to symbiotic plasmids showed high levels of nucleotide identity (about 98 to 99%), whereas chromosomal sequences and the sequences with matches to other plasmids showed lower levels of identity (on average, about 90 to 95%). We concluded that R. etli has a pangenomic structure with a core genome composed of both chromosomal and plasmid sequences, including a highly conserved symbiotic plasmid, despite the overall genomic divergence.

Restriction map

Genomic Organization

10.1128/aem.02039-09

Cite

Citations (60)

New Horizons in Nitrogen Fixation

Current plant science and biotechnology in agriculture (1993)

Rafael Palacios Jaime Mora William E. Newton

New horizons

10.1007/978-94-017-2416-6

Cite

Citations (364)