Papers by jOSE lUIS GARCIA
Osaka Journal of Mathematics, 1994
It is well known that over a left Notherian ring any direct sum of injecive modules is again inje... more It is well known that over a left Notherian ring any direct sum of injecive modules is again injective, and every injective module is a direct sum of indecomposable modules. Faith introduced Σ-injective modules as modules M such that all direct sums of copies of M are injective. Cailleau showed that a Σ-injective module is a direct sum of indecomposable modules. The concept of Σ-injective modules had several intersting developments and applications (see e.g. Faith ). Also, some generalizations of Σ-injective modules, such as Σ-quasi-injective modules (Cailleau-Renault [3]), or Σ-M-injecitve modules (Albu-Nastasescu [1]), were studied. Of special interest are Σ-pure-injective modules which were introduced and investigated extensively by W. Zimmermann and B. Zimmermann-Huisgen . These modules include, besides Σ-injective modules, also Π-projective modules (i.e., modules M such that all direct products of copies of M are projective).
Environmental Microbiology, 2002
Analysis of the catabolic potential of Pseudomonas putida KT2440 against a wide range of natural ... more Analysis of the catabolic potential of Pseudomonas putida KT2440 against a wide range of natural aromatic compounds and sequence comparisons with the entire genome of this microorganism predicted the existence of at least four main pathways for the catabolism of central aromatic intermediates, that is, the protocatechuate ( pca genes) and catechol ( cat genes) branches of the β β β β -ketoadipate pathway, the homogentisate pathway ( hmg / fah / mai genes) and the phenylacetate pathway ( pha genes). Two additional gene clusters that might be involved in the catabolism of N-heterocyclic aromatic compounds ( nic cluster) and in a central meta -cleavage pathway ( pcm genes) were also identified. Furthermore, the genes encoding the peripheral pathways for the catabolism of phydroxybenzoate ( pob ), benzoate ( ben ), quinate ( qui ), phenylpropenoid compounds ( fcs , ech , vdh , cal , van , acd and acs ), phenylalanine and tyrosine ( phh , hpd ) and n -phenylalkanoic acids ( fad ) were mapped in the chromosome of P. putida KT2440. Although a repetitive extragenic palindromic (REP) element is usually associated with the gene clusters, a supraoperonic clustering of catabolic genes that channel different aromatic compounds into a common central pathway (catabolic island) was not observed in P. putida KT2440. The global view on the mineralization of aromatic compounds by P. putida KT2440 will facilitate the rational manipulation of this strain for improving biodegradation/biotransformation processes, and reveals this bacterium as a useful model system for studying biochemical, genetic, evolutionary and ecological aspects of the catabolism of aromatic compounds.
Molecular Microbiology, 2001
The term catabolon was introduced to define a complex functional unit integrated by different cat... more The term catabolon was introduced to define a complex functional unit integrated by different catabolic pathways, which are, or could be, co-ordinately regulated, and that catalyses the transformation of structurally related compounds into a common catabolite. The phenylacetyl-CoA catabolon encompasses all the routes involved in the transformation of styrene, 2-phenylethylamine, trans-styrylacetic acid, phenylacetaldehyde, phenylacetic acid, phenylacetyl amides, phenylacetyl esters and n-phenylalkanoic acids containing an even number of carbon atoms, into phenylacetyl-CoA. This common intermediate is subsequently catabolized through a route of convergence, the phenylacetyl-CoA catabolon core, into general metabolites. The genetic organization of this central route, the biochemical significance of the whole functional unit and its broad biotechnological applications are discussed.
Molecular Microbiology, 1999
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Fems Microbiology Letters, 1992
Molecular Microbiology, 1999
A biochemical approach to identify proteins with high affinity for choline-containing pneumococca... more A biochemical approach to identify proteins with high affinity for choline-containing pneumococcal cell walls has allowed the localization, cloning and sequencing of a gene (lytC ) coding for a protein that degrades the cell walls of Streptococcus pneumoniae. The lytC gene is 1506 bp long and encodes a protein (LytC) of 501 amino acid residues with a predicted M r of 58 682. LytC has a cleavable signal peptide, as demonstrated when the mature protein (about 55 kDa) was purified from S. pneumoniae. Biochemical analyses of the pure, mature protein proved that LytC is a lysozyme. Combined cell fractionation and Western blot analysis showed that the unprocessed, primary product of the lytC gene is located in the pneumococcal cytoplasm whereas the processed, active form of LytC is tightly bound to the cell envelope. In vivo experiments demonstrated that this lysozyme behaves as a pneumococcal autolytic enzyme at 30 degrees C. The DNA region encoding the 253 C-terminal amino acid residues of LytC has been cloned and expressed in Escherichia coli. The truncated protein exhibits a low, but significant, choline-independent lysozyme activity, which suggests that this polypeptide adopts an active conformation. Self-alignment of the N-terminal part of the deduced amino acid sequence of LytC revealed the presence of 11 repeated motifs. These results strongly suggest that the lysozyme reported here has changed the general building plan characteristic of the choline-binding proteins of S. pneumoniae and its bacteriophages, i.e. the choline-binding domain and the catalytic domain are located, respectively, at the N-terminal and the C-terminal moieties of LytC. This work illustrates the natural versatility exhibited by the pneumococcal genes coding for choline-binding proteins to fuse separated catalytic and substrate-binding domains and create new and functional mature proteins.
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Papers by jOSE lUIS GARCIA