Juan Salvador Aguilar

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The FucO protein, a member of the group III "iron-activated" dehydrogenases, catalyzes the interconversion between L-lactaldehyde and L-1,2-propanediol in Escherichia coli. The three-dimensional structure of FucO in a complex with NAD(+) was solved, and the presence of iron in the crystals was confirmed by X-ray fluorescence. The FucO structure presented(More)
We isolated an Escherichia coli mutant strain that suppresses the glycolate-negative phenotype of a strain deficient in both GlcA and LldP transporters of this compound. This suppressing phenotype was assigned to yjcG, a gene whose function was previously unknown, which was found to encode a membrane protein able to transport glycolate. On the basis of(More)
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a multifunctional housekeeping protein secreted by pathogens and involved in adhesion and/or virulence. Previously we reported that enterohemorrhagic (EHEC) and enteropathogenic (EPEC) Escherichia coli secrete GAPDH into the culture medium. This bacterial protein binds human plasminogen and fibrinogen and(More)
Conservation diagnosis should identify which demographic parameters (or vital rates) are having a negative effect on the population growth rate of a threatened organism. Diagnosis can analyse how the environment is influencing the vital rates of this organism. In the present study, we tried to improve the diagnosis of a critically endangered seabird, the(More)
This article describes ways in which receptors, key components of signal propagation through a synapse, can mediate changes in that propagation. Changes occur at four levels: in the signal-transducing capability of a single receptor molecule, in the number of receptors per cell, in the subcellular placement of receptor molecules, and in the cytoarchitecture(More)
The allantoin regulon of Escherichia coli, formed by three operons expressed from promoters allA(P), gcl(P) and allD(P), is involved in the anaerobic utilization of allantoin as nitrogen source. The expression of these operons is under the control of the repressor AllR. The hyperinduction of one of these promoters (allD(P)) by allantoin in an AllR defective(More)
The lldPRD operon of Escherichia coli, involved in L-lactate metabolism, is induced by growth in this compound. We experimentally identified that this system is transcribed from a single promoter with an initiation site located 110 nucleotides upstream of the ATG start codon. On the basis of computational data, it had been proposed that LldR and its(More)
Growth experiments showed that adenine and hypoxanthine can be used as nitrogen sources by several strains of K. pneumoniae under aerobic conditions. The assimilation of all nitrogens from these purines indicates that the catabolic pathway is complete and proceeds past allantoin. Here we identify the genetic system responsible for the oxidation of(More)
The ula regulon, responsible for the utilization of L-ascorbate in Escherichia coli, is formed by two divergently transcribed operons, ulaG and ulaABCDEF. The regulon is negatively regulated by a repressor of the DeoR family which is encoded by the constitutive gene ulaR located downstream of ulaG. Full repression of the ula regulon requires simultaneous(More)
When exposed to enteric pathogens intestinal epithelial cells produce several cytokines and other proinflammatory mediators. To date there is no evidence that the ether-lipid platelet-activating factor (PAF) is one of these mediators. Our results revealed a significant increase in PAF production by human colonic tissue 4 h after infection by(More)