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Biomedical subjects

M A Ferrer

Publications and source records attributed to M A Ferrer.

11 recordsLinked to original sources
PubMed2003

A poly(ADP-ribose) polymerase haplotype spanning the promoter region confers susceptibility to rheumatoid arthritis.

OBJECTIVE: To investigate the association of the poly(ADP-ribose) polymerase 1 (PARP-1) gene promoter polymorphism with rheumatoid arthritis (RA) predisposition. METHODS: An association study with 213 Spanish RA patients and 242 healthy subjects was carried out to investigate the association of all known PARP-1 gene promoter polymorphisms, i.e., a CA microsatellite repeat, a poly(A)(n), and 3 single point mutations (C410T, C1362T, and G1672A), with disease susceptibility. Additionally, we analyzed the distribution of PARP-1 polymorphisms in 58 Spanish families with 1 or more affected members. RESULTS: Upon complete genotyping of the panel of 455 samples, strong linkage disequilibrium was observed among the 5 PARP-1 polymorphisms. Only 2 PARP-1 haplotypes were detected: haplotype A (410T-[A](10)-[CA](10-12)-1362C, which includes short PARP-1 CA alleles) and haplotype B (410C-[A](11)-[CA](13-20)-1362T, always paired with long PARP-1 CA variants). Regarding the G1672A variation, although linkage disequilibrium was detected, it did not seem to be part of the conserved haplotypes described. Haplotype B was statistically overrepresented in the RA patient group compared with the healthy subjects (odds ratio 1.42, 95% confidence interval 1.06-1.91, P = 0.019). In addition, a significant dose effect of PARP-1 haplotype carriage on disease predisposition was observed. Of note, within haplotype B, the PARP-1 CA 97-bp allele was found to be the RA-predisposing marker (odds ratio 2.17, 95% confidence interval 1.27-3.72, P = 0.003, corrected P < 0.05). CONCLUSION: Our results demonstrate the existence of 2 unique PARP-1 haplotypes in the Spanish population and provide the first evidence that PARP-1 haplotypes play a role in susceptibility to RA.

Arthritis, Rheumatoid↗
PubMed2001

Antioxidant systems and O(2)(.-)/H(2)O(2) production in the apoplast of pea leaves. Its relation with salt-induced necrotic lesions in minor veins.

The present work describes, for the first time, the changes that take place in the leaf apoplastic antioxidant defenses in response to NaCl stress in two pea (Pisum sativum) cultivars (cv Lincoln and cv Puget) showing different degrees of sensitivity to high NaCl concentrations. The results showed that only superoxide dismutase, and probably dehydroascorbate reductase (DHAR), were present in the leaf apoplastic space, whereas ascorbate (ASC) peroxidase, monodehydroascorbate reductase (MDHAR), and glutathione (GSH) reductase (GR) seemed to be absent. Both ASC and GSH were detected in the leaf apoplastic space and although their absolute levels did not change in response to salt stress, the ASC/dehydroascorbate and GSH to GSH oxidized form ratios decreased progressively with the severity of the stress. Apoplastic superoxide dismutase activity was induced in NaCl-treated pea cv Puget but decreased in NaCl-treated pea cv Lincoln. An increase in DHAR and GR and a decrease in ASC peroxidase, MDHAR, ASC, and GSH levels was observed in the symplast from NaCl-treated pea cv Lincoln, whereas in pea cv Puget an increase in DHAR, GR, and MDHAR occurred. The results suggest a strong interaction between both cell compartments in the control of the apoplastic ASC content in pea leaves. However, this anti-oxidative response does not seem to be sufficient to remove the harmful effects of high salinity. This finding is more evident in pea cv Lincoln, which is characterized by a greater inhibition of the growth response and by a higher rise in the apoplastic hydrogen peroxide content, O(2)(.-) production and thiobarbituric acid-reactive substances, and CO protein levels. This NaCl-induced oxidative stress in the apoplasts might be related to the appearance of highly localized O(2)(.-)/H(2)O(2)-induced necrotic lesions in the minor veins in NaCl-treated pea plants. It is possible that both the different anti-oxidative capacity and the NaCl-induced response in the apoplast and in the symplast from pea cv Puget in comparison with pea cv Lincoln contributes to a better protection of pea cv Puget against salt stress.

Adaptation, Physiological↗
PubMed1999

Does diphenylene iodonium chloride have any effect on the O2- -generating step of plant peroxidases?

The O2*- -generating step of plant peroxidases during their catalytic cycle is represented by the decay of compound III (CoIII) into ferriperoxidase, which most likely involves the dissociation of a ferric-O2*- complex to yield the ferric form of the enzyme and O2*-. Diphenylene iodonium chloride (DPI), at 50-100 microM, does not significantly enhance the stability of CoIII of peroxidase, as judged by the values of k(decay), and therefore, DPI appears to have no effect on the O2*- -generating step of plant peroxidases. From these results, it is concluded that caution should be exercised when considering peroxidase as a possible enzyme target of O2*- -mediated plant physiological processes sensitive to DPI inhibition.

Electrophoresis, Polyacrylamide Gel↗
PubMed1998

Expression and characterization of three tomato 1-aminocyclopropane-1-carboxylate oxidase cDNAs in yeast.

Heterologous expression in yeast has previously shown that the tomato cDNA LE-ACO1 encodes a functional 1-aminocyclopropane-1-carboxylate (ACC) oxidase (ACO) protein [Hamilton, A. J., Bouzayen, M. & Grierson, D. (1991) Proc. Natl Acad. Sci. USA 88, 7434-7437]. In the present work, full-length cDNAs encoding the two other members of the tomato ACO family (LE-ACO2 and LE-ACO3) were isolated and expressed in Saccharomyces cerevisiae. Analysis of the predicted amino acid sequences showed that the ACO1 and ACO3 proteins are highly similar (95%) while ACO2 is more divergent (89%). Yeast strains transformed with each of the three cDNAs were able to convert exogenous ACC to ethylene, the ACO1 strain exhibiting the highest activity in vivo and the ACO3 and ACO2 strains reaching 65% and 45% of ACO1 maximum activity, respectively. None of the ACO activities expressed in yeast required addition of ascorbate in vivo. ACO activities assayed in vitro revealed no significant differences between the three isoforms with regards to optimum temperature (29 degrees C), optimum pH (6.8-7.2), absolute dependence for ascorbate, Fe2+ and carbon dioxide, and inhibition by iron-chelating agents (1,10-phenanthroline and EDTA), Co2+ and free-radical scavengers (n-propyl gallate). However, differences were detected in the apparent Km values for ACC, the pI and the specific activity. The biochemical features that might explain the differences between the isoenzyme activities are discussed.

Amino Acid Oxidoreductases↗
PubMed1995

Effect of fosetyl-A1 on peroxidase from grapevine (Vitis vinifera) cells.

Grapevine (Vitis vinifera cv. Monastrell) suspension cell cultures were treated with fosetyl-A1, a widely used systemic fungicide for grapevine diseases caused by oomycetes, and examined at the electron microscope level for peroxidase cytochemistry. The results showed that treatment with fosetyl-A1 provokes an activation of both vacuolar sap and tonoplast-located peroxidase, already described as due to the basic peroxidase isoenzyme, B5, which was previously characterized as a constitutive marker of disease resistance against Plasmopara viticola in axillary bud cultures of Vitis spp. This activation of peroxidase isoenzyme B5, as seen at the electron microscope level, was confirmed by cytophotometric methods, but is in contrast with the unchanged enzyme level determined by biochemical methods. These results suggest a metabolic activation of peroxidase isoenzyme B5 as a consequence of fosetyl-A1 treatment, probably due to an acidification of the vacuole. This response was accompanied by the appearance of myelin-like structures inside the cytoplasm and osmiophylic-bodies inside the mitochondria. However, the latter structural changes cannot easily be related to the above described specific peroxidase response.

Biotransformation↗
PubMed1994

Purification of a basic peroxidase isoenzyme from Capsicum fruits and the immunoinhibition of its capsaicin oxidation capacity by antibodies raised against horseradish peroxidase.

Pepper fruits contain a peroxidase isoenzyme of basic pI, the peroxidase isoenzyme B6, located in vacuoles and the principal component of peroxidase polymorphism in the whole fruit. This isoenzyme was purified by preparative isoelectric focusing in glycerol-stabilized 3.0-10.0 pH gradients and characterized for its ability to oxidize capsaicin (8-methyl-N-vanillyl-6-nonenamide). Spectrophotometric studies illustrated that the capsaicin oxidation by pepper peroxidase isoenzyme B6 was H2O2-dependent and was totally abolished by antibodies raised against horseradish peroxidase. From these studies, it can be concluded that capsaicin is oxidized by pepper peroxidase isoenzyme B6, thus confirming a role for this peroxidase isoenzyme in capsaicin turnover and degradation.

Animals↗
PubMed1992

Hammett rho sigma correlation for the inhibition by indoles of coniferyl alcohol oxidation catalyzed by cell wall peroxidases.

The inhibitory effect of indole-3-acetic acid, and of its peroxidase-mediated degradation products of an indole nature, on the oxidation rate of coniferyl alcohol catalyzed by cell wall peroxidases has been studied. The results show that the inhibitory effect of indole-3-acetic acid and indole-3-carbinol may be explained, in part, by their properties as peroxidase substrates. However, I50 values for a series of indole compounds not regarded as peroxidase substrates show a good correlation with the electron-donating or electron-withdrawing nature of the 3-substituents, as judged by the linearity of the Hammett rho sigma plot. These results suggest that although the properties of indole compounds as peroxidase substrates may be responsible, in part, for their inhibitory effects on the peroxidase-mediated oxidation of coniferyl alcohol, the inhibitory effect appears to be mainly determined by the acidity of the imino group of the indole nucleus.

Catalysis↗
PubMed1991

A comparative study of a progestin-only oral contraceptive versus non-hormonal methods in lactating women in Buenos Aires, Argentina.

A non-randomized comparative clinical trial of the progestin-only oral contraceptive (POC), Ovrette (75 mcg norgestrel) (Wyeth), versus non-hormonal methods was conducted at two clinics in Buenos Aires, Argentina. The trial was designed to assess the breast-feeding patterns of women choosing progestin-only oral contraception and non-hormonal methods of contraception, and to study the relationship between lactation and the clinical performance of a POC. Five-hundred women were allocated to either the progestin-only pill group (n = 250) or to the non-hormonal group (n = 250) and were followed up monthly for six months after admission. Measurements in mean infant weight, mean infant length, and mean head circumference were similar throughout the follow-up period. Non-hormonal users reported significantly more self-perceived decreases in milk production at the 5th and 6th month follow-up intervals. Acceptance and continued use of the pill were excellent, with only one woman discontinuing because of a pregnancy which was attributed to user failure. The principal side effect reported by women in both groups was intermenstrual bleeding.

Adolescent↗
PubMed1990

Oxidation of coniferyl alcohol by cell wall peroxidases at the expense of indole-3-acetic acid and O2. A model for the lignification of plant cell walls in the absence of H2O2.

The oxidation of coniferyl alcohol (CA), a lignin precursor, by cell wall peroxidases may take place at the expense of indole-3-acetic acid (IAA) and O2, and in the absence of H2O2. The peroxidase-catalyzed oxidation of CA shows an optimum at an IAA concentration of 0.33 mM, while higher IAA concentrations are inhibitory. The observation that the oxidation of CA by cell wall peroxidase at the expense of IAA and O2 is inhibited by genistein, a putative endogenous inhibitor of lignification in lupin hypocotyls, supports the view that the H2O2-generating system coexists with cell wall peroxidase activities involved in lignification, and that it takes place at the expense of IAA and O2.

Cell Wall↗