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F Garcia-Olmedo

Publications and source records attributed to F Garcia-Olmedo.

10 recordsLinked to original sources
PubMed1997

Differential effects of five types of antipathogenic plant peptides on model membranes.

The effects of five antipathogenic plant peptides, wheat alpha-thionin, potato PTH1 defensin, barley LTP2 lipid transfer protein, and potato tuber DL1 and DL2 defensins, have been tested against phospholipid vesicles (liposomes). Wheat thionin very actively induces aggregation and leakage of negatively charged vesicles. LTP2 displays the same activities, although to a limited extent. Under certain conditions PTH1 and DL2 induce vesicle aggregation, but not leakage. Potato defensin DL1 failed to show any effect on liposomes. The same peptides have been assayed against a plant pathogenic bacterium, both the membrane-active and -inactive compounds having efficient antibacterial action.

Anti-Infective Agents↗
PubMed1995

Selective disulphide linkage of plant thionins with other proteins.

Thionins are shown to form disulphide linkages with other proteins. The reaction with bacterial enzymes beta-glucuronidase and neomycin phosphotransferase II could be prevented and reversed with dithiothreitol and blocked with N-ethylmaleimide. Other cysteine-rich low-molecular-weight toxic peptides from plants (LTP-3 from barley and P19 from potato) did not react as the thionins. Certain cysteine-containing proteins, such bovine serum albumin, ovalbumin and cytochrome c, reacted with thionins, while others, including carbonic anhydrase, soybean trypsin inhibitor, bovine-lung trypsin inhibitor and phosphorylase B did not. Selectivity of the reaction with a periplasmic component of the phytopathogenic bacterium Pseudomonas solanacearum was also shown.

Antimicrobial Cationic Peptides↗
PubMed1994

Dances to a redox tune.

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Gene Expression Regulation, Plant↗
PubMed1989

The gene for trypsin inhibitor CMe is regulated in trans by the lys 3a locus in the endosperm of barley (Hordeum vulgare L.).

A cDNA encoding trypsin inhibitor CMe from barley endosperm has been cloned and characterized. The longest open reading frame of the cloned cDNA codes for a typical signal peptide of 24 residues followed by a sequence which is identical to the known amino acid sequence of the inhibitor, except for an Ile/Leu substitution at position 59. Southern blot analysis of wheat-barley addition lines has shown that chromosome 3H of barley carries the gene for CMe. This protein is present at less than 2%-3% of the wild-type amount in the mature endosperm of the mutant Risø 1508 with respect to Bomi barley, from which it has been derived, and the corresponding steady state levels of the CMe mRNA are about 1%. One or two copies of the CMe gene (synonym Itc1) per haploid genome have been estimated both in the wild type and in the mutant, and DNA restriction patterns are identical in both stocks, so neither a change in copy number nor a major rearrangement of the structural gene account for the markedly decreased expression. The mutation at the lys 3a locus in Risø 1508 has been previously mapped in chromosome 7 (synonym 5H). A single dose of the wild-type allele at this locus (Lys 3a) restores the expression of gene CMe (allele CMe-1) in chromosome 3H to normal levels.

Amino Acid Sequence↗
PubMed1989

Wheat tetrameric inhibitors of insect alpha-amylases: Alloploid heterosis at the molecular level.

Tetrameric inhibitors of heterologous alpha-amylases have been characterized in allohexaploid wheat, Triticum aestivum (genomes AABBDD), as well as in Triticum turgidum (AABB) and Triticum tauschii (DD). Their subunits have been identified as the previously described CM proteins. Single oligomeric species were observed in T. Turgidum (subunits CM2, CM3A, and CM16) and in T. tauschii (CM1, CM3D, and CM17) by a two-dimensional electrophoretic method that does not dissociate the inhibitors in the first dimension. Multiple tetrameric species, resulting from different combinations of the subunits contributed by the two ancestral species, are observed by the same procedure in T. aestivum. The three types of subunits were required for significant activity when the inhibitor of T. turgidum was reconstituted from the purified subunits, whereas, in the case of T. tauschii, binary mixtures involving subunit CM1 also had some activity. Additional combinations of the subunits present in these two species, which occur in the allohexaploid T. aestivum, were also reconstituted, and their inhibitory activities ranged from 144% to 33% the activity of the reconstituted inhibitor from T. tauschii. The activity of these inhibitors toward the alpha-amylase (1,4-alpha-D-glucan glucanohydrolase, EC 3.2.1.1) of the insect Tenebrio molitor is much greater than that against the salivary enzyme. These observations, together with the previously established chromosomal locations of genes encoding CM proteins, fit a model of alloploid heterosis at the molecular level.

Journal Article↗
PubMed1988

Signal peptide homology between the sweet protein thaumatin II and unrelated cereal alpha-amylase/trypsin inhibitors.

A cDNA clone (pUP-23) corresponding to a member of a protein family that includes inhibitors of trypsin and of heterologous alpha-amylases has been selected from a library derived from developing barley endosperm and its sequence has been determined. A stretch of 95 nucleotides that included the signal peptide and the first 8 residues of the mature protein was found to be homologous to an exactly equivalent region of the nucleotide sequence encoding the sweet protein thaumatin II. Evolutionary implications of this finding are discussed.

Amino Acid Sequence↗
PubMed1988

Two-dimensional electrophoresis as a tool for structural and genetic studies of seed proteins from Poaceae and Fagaceae.

The application of two-dimensional electrophoretic procedures to structural and genetic studies of seed proteins from Poaceae (including the cultivated cereals) and Fagaceae is described. The following related problems have been considered: covalent and non-covalent association of protein subunits in multiple oligomeric structures; chromosomal locations of genes encoding seed proteins; quantitation of gene products in relation to gene expression and regulation; purification of protein components to study their homology relationships and in vitro activities; evolutionary and phylogenetic relationships; identification of genetic stocks. Isoelectric focusing, pore-gradient electrophoresis, electrophoresis at different pH's, are among the separation procedures used in the first dimension, whereas sodium dodecyl sulfate-polyacrylamide gel electrophoresis and starch-gel electrophoresis at acid pH have been the preferred second-dimensional methods. Dissociating conditions (sodium dodecyl sulfate, Nonidet P-40, or urea) and reducing conditions (2-mercaptoethanol) have been used when required.

Aneuploidy↗
PubMed1986

New alpha-amylase and trypsin inhibitors among the CM-proteins of barley (Hordeum vulgare).

Barley CM-proteins are a group of at least five salt-soluble components (CMa-e) that can be selectively extracted from endosperm with chloroform/methanol mixtures. N-terminal sequences of proteins CMa, CMb and CMc have been determined and found to be homologous to those previously determined for CMd and CMe, an observation which confirms that their structural genes are members of a dispersed multi-gene family. The purified CM-proteins were tested against trypsin and against alpha-amylases from saliva, pancreas, Aspergillus oryzae, Tenebrio molitor and barley. Besides CMe, which was known to be a trypsin inhibitor, CMc also showed antitrypsin activity, whereas CMa was specifically active against the alpha-amylase from T. molitor and no inhibitory activity was found for proteins CMb and CMd. The evolutionary implications of these findings are discussed.

Amino Acid Sequence↗
PubMed1975

Genetic control of sterol esterification in developing wheat endosperm.

1. The action of gene Pln, previously characterized by the sterol ester patterns of mature whole wheat kernels, has been found to be restricted to the endosperm and not to affect the embryo, the pericarp or the seed coat. 2. The dominant allele Pln, which determines a sterol ester pattern with palmitate as the main ester, is also responsible for a low level of free sterol at maturity. A high level of free sterol is associated with the recessive allelet pln, which determines an ester pattern with linoleate as the main ester. 3. Divergence between the two phenotypes starts at about 21 days after anthesis, when cell proliferation has been completed, the aleurone layer has differentiated, and only cell enlargement is taking place. A marked increased in esterification, mainly by palmitate, which is controlled by the dominant allele, is concomitant with a sharp decrease in free sterol. 4. The increased net esterification is non-specific with respect to 4-demethyl sterols, because it affects the four main ones, namely sitosterol, stigmasterol, campesterol and cholesterol.

Alleles↗