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Biomedical subjects

M Potenza

Publications and source records attributed to M Potenza.

9 recordsLinked to original sources
PubMed2006

Analysis of the Trypanosoma cruzi cyclophilin gene family and identification of Cyclosporin A binding proteins.

The Trypanosoma cruzi cyclophilin gene family comprises 15 paralogues whose nominal masses vary from 19 to 110 kDa, namely TcCyP19, TcCyP20, TcCyP21, TcCyP22, TcCyP24, TcCyP25, TcCyP26, TcCyP28, TcCyP29, TcCyP30, TcCyP34, TcCyP35, TcCyP40, TcCyP42 and TcCyP110. Under the conditions used, only some of the T. cruzi cyclophilin paralogue products could be isolated by affinity chromatography. The 15 paralogues were aligned with 495 cyclophilins from diverse organisms. Analyses of clusters formed by the T. cruzi cyclophilins with others encoded in various genomes revealed that 8 of them (TcCyP19, TcCyP21, TcCyP22, TcCyP24, TcCyP35, TcCyP40, TcCyP42 and TcCyP110) have orthologues in many different genomes whereas the other 7 display less-defined patterns of their sequence attributes and their classification to a specific group of cyclophilin's orthologues remains uncertain. Seven epimastigote cDNA clones encoding cyclophilin isoforms were further studied. These genes were found dispersed throughout the genome of the parasite. Amastigote and trypomastigote mRNAs encoding these 7 genes were also detected. We isolated 4 cyclosporin A-binding proteins in T. cruzi epimastigote extracts, which were identified by mass spectrometry as TcCyP19, TcCyP22, TcCyP28 and TcCyP40. Cyclosporin A-binding to these cyclophilins might be of importance to the mechanism of action of Cyclosporin A and its non-immunosuppressive analogues, whose trypanocidal effects were previously reported, and therefore, of potential interest in the chemotherapy of Chagas' disease.

Amino Acid Sequence↗
PubMed1992

SEC6 encodes an 85 kDa soluble protein required for exocytosis in yeast.

The SEC6 gene encodes a protein required for an event leading to fusion of post-Golgi vesicles with the plasma membrane in Saccharomyces cerevisiae cells. The gene was cloned by complementation of the temperature-sensitive growth defect of a sec6-4 strain. The nucleotide sequence was determined and the longest open reading frame was found to encode an 85 kDa protein of 733 amino acids. The Sec6 protein is predicted to be hydrophilic and is found predominantly in the soluble fraction of a yeast lysate, in a species that sediments with a coefficient of 14S. No extensive homology was found with known proteins of the database. Gene disruption and marker rescue experiments indicate that SEC6 is a single copy gene essential for growth. Overproduction of Sec6p does not suppress any of the other late-acting sec mutants, yet sec6-4 does display synthetic lethality with sec8-9, suggesting that the two gene products may fulfill inter-related functions.

Amino Acid Sequence↗
PubMedDate not supplied

[Hypersensitiviy to Trichophyton rubrum antigens in atopic and non-atopic podiatrists].

BACKGROUND: Podiatrists as well as manicurists are exposed to inhale nail dust contaminated with mycotic particles when filing and burring the onychomycotic nails of their patients. As some of them with atopic background suffered worsening of their symptoms we decided to study the immune response to the fungus Trichophyton rubrum (Tr) that was isolated from the nail dust obtained from the podiatrists office. METHODOLOGY AND RESULTS: A detailed clinical record, intracutaneous skin tests with a extract of Tr and the serum levels of total and specific IgE were performed in rhinitis-asthma as well as control patients. As the asthmatic group refused to perform the challenge bronchial test with Tr we developed a guinea pig experimental model with daily aerosolization of Tr during 12 weeks studying the levels of specific IgE and IgG as well as the lung's histopathology. Atopic patients showed positive immediate skin tests with Tr and both groups revealed delayed hypersensitivity to the antigen.RAST-IgE-anti-Tr and RAST-inhibition confirmed the specificity of the antibodies. Guinea pigs also synthetized IgG and IgE anti-Tr and suffered different degrees of lung lesions similar to those of hypersensitivity pneumonitis. CONCLUSION: Atopic podiatrists are exposed to fungal allergens that may participate or aggravate their previous respiratory conditions.

Adult↗
PubMedDate not supplied

[Hypersensitivity pneumonitis induced in guinea pigs by antigens to bat feces].

A bat feces extract was able to induce the synthesis of specific IgG in rabbits and IgE in atopics. These findings were corroborated by skin tests, RAST and RAST-inhibition. Nowadays, data concerning the experimental induction of hypersensitivity pneumonitis using a glycoprotein of bat feces are presented. This antigen was aerosolized for inhalation by adult guinea pigs for 12 weeks to detect specific serum IgM, IgG and IgE antibodies as well as sensitized T-CD4 cells. Histopathological studies of the lungs showed interstitial infiltrates of macrophages and lymphocytes, cellular bronchiolitis and single non-necrotizing granulomas from the seventh to the ninth weeks. From the tenth week to the end of the experiment the lesions of the lungs progressively worsened. The results from this animal model suggest that the chronic contact with the bat feces'antigen can induce other inflammatory lung reactions than those IgE dependant.

Aerosols↗
PubMedDate not supplied

Proteinase and gelatinolytic properties of a bat feces extract.

It was previously demonstrated that a bat feces extract (BAT) was able to produce a specific IgG in animals, a specific IgE in respiratory atopic humans and a hypersensitivity pneumonitis in guinea pigs. As numerous allergens (such as house-dust mite, cockroaches and pollens) revealed a enzymatic activity measured by different assays we decided to study the proteinase and the gelatinolytic activities of the BAT. Several protease inhibitors such as E-64, TLCK, TPCK, PMSF, leupeptin, o-phenantroline and pepstatin-A were applied to establish the chemical properties of the enzymatic activity. These assays revealed a serine-trypsin-like proteolytic and gelatinolytic activities specially at pH 8,5. On the other hand, two bands of 21 and 40 kDa reacted with the human atopic sera suggesting a possible correlation between allergenicity and proteinase activity. Their role in the etiology of perennial rhinitis and asthma requires further investigations.

Allergens↗
PubMedDate not supplied

Proteinase and gelatinolytic properties of a Triatoma infestans extract.

An extract of Triatoma infestans has previously been demonstrated to produce specific IgG and IgE both in animals and in atopic humans with rhinitis/asthma as well as hypersensitivity pneumonitis in guinea pigs aerosolized with T. infestans. We attempted to determine whether the antigen or antigens responsible belonged to the protease group, as occurs with other allergens such as house dust mites and cockroaches. To do this, T. infestans was studied by SDS-PAGE, Western blots and gelatinolysis with and without the use of specific protease inhibitors such as E-64, TLCK, TPCK, PMSF, leupeptin, o-phenanthrolene and pepstatin-A. These assays revealed serine-like proteolytic and gelatinolytic activities. The presence of 10 to 12 bands of between 14 and 100 kDa was detected. The proteolytic activity pattern of T. infestans was greatest at pH 8.5 and gelatinolytic activity was highly sensitive to PMSF, suggesting that this enzyme could be characterized as a serine protease. Western blots revealed that two bands of 17 and 58 kDA reacted with the sera of atopic humans with respiratory diseases and anti-IgE. However, whether these bands correlated with allergenicity is unclear since the presence of several proteins in each of these bands does not rule out the possibility that this correlation could exist, especially because cross-reactions with antigens from the cockroach Periplaneta americana and its specific antiserum in animals and atopic humans have been demonstrated. The role of proteases in the etiopathogenesis of perennial rhinitis and bronchial asthma in inhabitants of the area of Argentina infested by T. infestans requires further investigation.

Allergens↗