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P Tornero

Publications and source records attributed to P Tornero.

34 records · Page 2Linked to original sources
PubMed1997

Identification of a new pathogen-induced member of the subtilisin-like processing protease family from plants.

By using biochemical, immunological, and molecular strategies we have identified and cloned a cDNA encoding a protease from tomato (Lycopersicon esculentum) plants (P69B) that is part of a proteolytic system activated in the plant as a result of infection with citrus exocortis viroid. This new protease is closely related, in terms of amino acid sequence and structural organization, to the previously identified pathogenesis-related subtilisin-like protease (Tornero, P., Conejero, V., and Vera, P. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 6332-6337). The 745-residue amino acid sequence of P69B begins with a cleavable signal peptide, contains a prodomain and a 631-residue mature domain which is homologous to the catalytic modules of bacterial subtilisins and eukaryotic Kex2-like proteases. Within the catalytic domain, the essential Asp, His, and Ser residues that conform the catalytic triad of this family of proteases are conserved in P69B. Northern blot and reverse transcriptase-polymerase chain reaction analysis demonstrated widespread induced expression of the 2.5-kilobase hybridizing mRNA in plant tissues as a consequence of viroid infection. We propose that P69B is a member of a complex gene family of plant Kex2/subtilisin-like proteases presumably involved in a number of specific proteolytic events activated during pathogenesis in plants and that takes place in the extracellular matrix.

Amino Acid Sequence↗
PubMed1997

Two PR-1 genes from tomato are differentially regulated and reveal a novel mode of expression for a pathogenesis-related gene during the hypersensitive response and development.

Pathogenesis-related (PR) proteins form a heterogeneous family of plant proteins that are likely to be involved in defense and are inducible by pathogen attacks. One group of PRs, represented by the subfamily PR-1, are low-molecular-weight proteins of unknown biochemical function. Here we describe the cloning and characterization of two closely related genes encoding a basic and an acidic PR-1 protein (PR1b1 and PR1a2) from tomato (Lycopersicon esculentum). We present a comparative study of the mode of transcriptional regulation of these two genes in transgenic tobacco plants using a series of promoter-GUS fusions. Unexpectedly, the chimeric PR1a2/GUS gene is not induced by pathogenic signals but instead shows constitutive expression with a reproducible developmental expression pattern. It is expressed in shoot meristems, trichomes, and cortical cells as well as in vascular and nearby tissues of the mature stem. This constitutive expression pattern may represent preemption of plant defenses against potential pathogens. Conversely, the chimeric PR1b1/GUS gene does not show any constitutive expression in the plant, but it is transcriptionally activated following pathogen attack. Upon infection by tobacco mosaic virus, the PR1b1 gene is strongly activated locally in tissues undergoing the hypersensitive response but not systemically in uninoculated tissues. Furthermore, its expression is induced by both salicylic acid and ethylene precursors, two signals that coexist and apparently mediate the activation of local defenses during the hypersensitive response. We speculate that the different mode of expression of the two genes presented here, together with that reported previously for the induction of other PR-1 genes in systemic, uninoculated tissues, may all be complementary and necessary for the plant to acquire an efficient refractory state to resist pathogen attacks.

Amino Acid Sequence↗
PubMed1997

Serum tryptase levels in adverse drug reactions.

We evaluated the usefulness of individual tryptase levels and variations after adverse drug reactions in 64 patients. Our aim was to find a tool for the diagnosis of drug allergy. Thirty-seven subjects were confirmed to have drug allergy, 12 had nonsteroidal anti-inflammatory drug (NSAID) reactions, five had negative controlled drug challenges (NAAR), and 10 had symptoms after placebo intake (PLA). Serum tryptase levels greatly increased after anaphylactic shocks (2242%) and anaphylaxis (710.5%). Patients with allergic urticaria and those with idiosyncratic responses to acetylsalicylic acid (ASA) exhibited a small increase in serum tryptase (49.5% and 38.2%, respectively). In the other two groups (NAAR and PLA), no variation in this serum protease was observed. The time of appearance of the serum tryptase peak differed considerably among patients with similar clinical reactions (from 30 min to 6 h) and was independent of the latent period, severity of symptoms, or the amount of tryptase released. We conclude that serum tryptase determinations are helpful in the diagnosis of anaphylactic shock and anaphylaxis, but serial measurements may be needed to confirm mast-cell participation in milder reactions.

Anaphylaxis↗
PubMed1996

Primary structure and expression of a pathogen-induced protease (PR-P69) in tomato plants: Similarity of functional domains to subtilisin-like endoproteases.

A 69-kDa proteinase (P69), a member of the pathogenesis-related proteins, is induced and accumulates in tomato (Lycopersicon esculentum) plants as a consequence of pathogen attack. We have used the polymerase chain reaction to identify and clone a cDNA from tomato plants that represent the pathogenesis-related P69 proteinase. The nucleotide sequence analysis revealed that P69 is synthesized in a preproenzyme form, a 745-amino acid polypeptide with a 22-amino acid signal peptide, a 92-amino acid propolypeptide, and a 631-amino acid mature polypeptide. Within the mature region the most salient feature was the presence of domains homologous to the subtilisin serine protease family. The amino acid sequences surrounding Asp-146, His-203, and Ser-532 of P69 are closely related to the catalytic sites (catalytic triad) of the subtilisin-like proteases. Northern blot analysis revealed that the 2.4-kb P69 mRNA accumulates abundantly in leaves and stem tissues from viroid-infected plants, whereas the mRNA levels in tissues from healthy plants were undetectable. Our results indicate that P69, a secreted calcium-activated endopeptidase, is a plant pathogenesis-related subtilisin-like proteinase that may collaborate with other defensive proteins in a general mechanism of active defense against attacking pathogens.

Amino Acid Sequence↗
PubMed1996

Characterization of LRP, a leucine-rich repeat (LRR) protein from tomato plants that is processed during pathogenesis.

This paper describes the isolation and characterization of LRP, a new gene from tomato plants. The deduced amino acid sequence showed that the encoded protein is enriched in leucine, and contains interesting structural motifs. LRP contains four tandem repeats of a canonical 24 amino acid leucine-rich repeat (LRR) sequence present in different proteins that mediates molecular recognition and/or interaction processes. Genomic organization and intron-exon arrangement of LRP favor the hypothesis that the LRR domains present in LRP evolved by exon duplication and shuffling. LRP expression analysis and immunohistochemical localization studies of the encoded protein indicate that the gene is under developmental regulation exhibiting tissue-specificity, particularly in certain cell types of the stele, like phloem fibers, parenchyma cells of the protoxylem, and in the cell files that constitute the rays of the secondary xylem. It is shown that this gene is upregulated in diseased tomato plants infected with citrus exocortis viroid. However, in this pathogenic context, LRP is processed proteolytically to a lower molecular weight form by a host-induced extracellular protease. The structural characteristics of LRP, its spatio-temporal pattern of expression, and its post-translational processing during pathogenesis, suggest this protein as a candidate molecule that may mediate recognition and interaction events taking place in the plant extracellular matrix under normal and/or pathogenesis-related conditions.

Amino Acid Sequence↗
PubMed1996

Phloem-specific expression of a plant homeobox gene during secondary phases of vascular development.

This paper reports the isolation and characterization of a homeobox gene (VAHOX1) from Lycopersicon esculentum encoding a homeodomain protein that contains a leucine zipper motif. The bipartite homeodomain-leucine zipper (HD-Zip) motif has only been found in homeobox genes from dicotyledonous plants, indicating that this type of transcription factor regulates particular developmental processes in these plant species. Here, the genomic organization, sequence comparison and expression analysis of VAHOX1 are described. Transcriptional fusion of the 5' promoter region of VAHOX1 with the reporter GUS gene (VAHOX1-GUS) and expression analysis of this construct in transgenic plants indicates that VAHOX1 is specifically expressed in the phloem during phases of secondary growth. Unlike other plant homeobox genes, VAHOX1 does not appear to be expressed in meristems, and the function of VAHOX1 is considered a likely candidate molecule that may participate in the regulation of the identity and/or activity of phloem tissues during secondary phases of vascular development.

Amino Acid Sequence↗
PubMed1994

A gene encoding a novel isoform of the PR-1 protein family from tomato is induced upon viroid infection.

A Lycopersicon esculentum cDNA clone encoding an acidic-type pathogenesis-related protein (PR-1a1) was isolated, sequenced and characterized. It contains an open reading frame of 175 amino acids and the mature protein, after cleavage of the 21 amino acid signals peptide, has a pI of 5.24. The protein shows highest homology (75% identity) with the basic pathogenesis-related prb-1b protein from tobacco. The PR-1a1 gene shows constitutive expression in roots from tomato plants. It is expressed in leaves and stems upon viroid infection, and appears to be induced by ethylene. Comparative studies of this gene and a related basic isoform of PR-1 indicate that the expression of these two members of the PR-1 gene family in tomato may be differentially regulated upon viroid infection.

Amino Acid Sequence↗
PubMed1993

cDNA cloning of viroid-induced tomato pathogenesis-related protein P23. Characterization as a vacuolar antifungal factor.

A 23-kD pathogenesis-related protein (P23) is induced in tomato (Lycopersicon esculentum Mill, cv Rutgers) plants when infected with citrus exocortis viroid. This protein is homologous to the salt-induced tomato NP24 protein (I. Rodrigo, P. Vera, R. Frank, V. Conejero [1991] Plant Mol Biol 16: 931-934). Further characterization of P23 has shown that this protein accumulates in vacuoles in association with dense inclusion bodies. In vitro assays indicated that the purified P23 protein inhibits the growth of several phytopathogenic fungi. P23-coding cDNA clones were isolated from viroid-induced and ethylene-induced libraries. Southern analysis showed that at least two genes could encode P23 or P23-related products. The accumulation of P23 protein correlated with the accumulation of its mRNA. Sequence analysis revealed significant differences in both coding and downstream untranslated regions between the cDNA sequences corresponding to the viroid-induced P23 and the salt stress-induced NP24 proteins.

Amino Acid Sequence↗
PubMed1992

Pathogenesis-related proteins and polyamines in a developmental mutant of tomato, epinastic.

The polyamine level and the accumulation of pathogenesis-related (PR) proteins were studied in the ethylene overproducing Epinastic (Epi) tomato (Lycopersicon esculentum Mill.) mutant, as compared with its parent, cv VFN8. Neither a decreased putrescine level nor an enhanced production of PR proteins were detected in Epi, contrary to what could be expected from our previous studies (JM Bellés, J Carbonell, V Conejero [1991] Plant Physiol 96: 1053-1059). However, treatment with the ethylene-releasing compound 2-chloroethylphosphonic acid (ethephon) or silver nitrate at high doses induced a decrease in putrescine content and an enhancing of the synthesis of PR proteins in Epi as ascertained by immunoblot analysis using antisera raised against Rutgers tomato PR proteins.

Journal Article↗
PubMedDate not supplied

Piroxicam-induced photodermatitis. Cross-reactivity among oxicams. A case report.

BACKGROUND: there is a group of patients with contact allergy to thimerosal (thiosalicylic acid and ethylmercuric chloride), thiosalicylic acid sensitized, who develop photodermatitis to piroxicam. We present a case which we have investigated cross-reactivity among different oxicams. METHODS AND RESULTS: a 44-year-old man with contact allergy to thimerosal. A few hours after the intake of Feldene (piroxicam) while running outside, developed a papuloerithematosus exanthema in the neck, knees and forearms, and microvesicles on the finger webs, that became descamative a few days later. Oclusive patch tests with thiosalicylic acid, mercury, piroxicam, tenoxicam, droxicam and meloxicam and photopatch test with the oxicams were performed. Patch tests with thiosalicylic acid and piroxicam were positive and negative with the others. All the oxicams photopatch tests were positive. CONCLUSIONS: we present a case of photodermatitis and dermatitis to piroxicam, in a patient with contact allergy to the thiosalicylic moiety of thimerosal, in which cross-reactivity with the other oxicams have been demonstrated. In cases of oxicams-induced photodermatitis, all oxicams should be avoided, to elude posible cross-reactions.

Adult↗
PubMedDate not supplied

Cloning and expression analysis of a viroid-induced peroxidase from tomato plants.

Differential hybridization was used to detect transcripts induced both by ethylene and by viroid infection in tomato plants. A cDNA clone encoding a putative peroxidase was isolated and characterized. DNA sequencing revealed high homology with a lignin-peroxidase from tobacco. Northern blot analysis showed specific induction of this peroxidase gene in viroid-infected plants. An increase in the level of mRNA accumulation is obtained by ethylene treatment, reinforcing the idea that ethylene is a mediator in the response of tomato plants to viroid infection.

Amino Acid Sequence↗
PubMedDate not supplied

Recurrent fixed drug eruption caused by citiolone.

Citiolone (N-acetylhomocysteinethiolactone) is a thiolic-derived medication frequently used in Spain and in other countries as a mucolytic agent for the treatment of certain hepatic disorders. Mucolytic drugs have rarely been implicated in the fixed drug eruption etiology. We report on a patient who presented several episodes of fixed exanthema related to citiolone intake. The patch test with citiolone (10% in dimethyl sulfoxide) was negative. The diagnosis was confirmed by a positive controlled oral challenge test. Other mucolytic thiolic-derivatives (N-acetylcysteine) were tolerated by the patient, thus crossreactivity between these drugs seems to be unlikely.

Acetylcysteine↗
PubMedDate not supplied

Fixed drug eruption induced by indapamide. Cross-reactivity with sulfonamides.

Indapamide is a nontiazidic sulfonamide diuretic which has not been previously reported as a cause of fixed drug eruption. We describe a patient who experienced several episodes of fixed drug eruption during treatment with indapamide. The diagnosis was confirmed by positive controlled oral challenge test. The possible existence of cross-reactivity with other sulfonamide derivatives was investigated by controlled oral challenge test with sulfamethoxazole, sulfadiazine and furosemide, with the tests with sulfamethoxazole and sulfadiazine resulting positive.

Aged↗