Effects of ascorbic acid addition on the oxidative stress response of Oryza sativa L. plants to As(V) exposure

Accumulation of noxious elements in the edible part of crops and its impact on food safety is of increasing concern. Rice is one of the major staple food crops worldwide, including arsenic (As)-polluted areas, in which dietary As exposure is becoming a widespread health threat. Plant chemical priming has been shown to be an effective strategy to enhance tolerance to environmental stresses, including metal(loid) exposure. The priming effect of ascorbic acid (AsA) was assessed in rice seedlings exposed to As(V) in a hydroponics experiment. AsA treatment (co-addition to the growing media concomitantly (t₀) or 24 h in advance (t₂₄)) prevented an excessive accumulation of As in the roots (that decreased ∼ 60%) and stimulated the activities of photosynthetic and antioxidant attributes (∼1.2-fold) in the aerial part of the plants. The increase in proline levels in both shoots (∼2.1-fold) and roots (∼2.4-fold) was found to be the most sensitive stress parameter, and was able to reflect the AsA-induced reduction of As toxic effects (concentrations back to Control levels, both simultaneously added or added as a pretreatment) in the aerial part of the plants. However, the phytotoxic effects related to As exposure were not fully prevented by priming with AsA, and further research is needed to find alternative priming approaches.

The aroma of La Mancha Chelva wines: Chemical and sensory characterization

The aim of this study is the chemical and sensory description of the aroma of wines white Chelva through five successive vintages. Solid Phase Extraction (SPE) was used for the isolation of volatile compounds and Gas Chromatography Mass Spectrometry (GC-MS) was employed by their analysis. Aroma Sensory Profile of wines was defined using the Quantitative Descriptive Sensory Analysis (QDA). A total of 77 volatile compounds were identified in Chelva wines. Chelva wines present a great quantity of aromatic compounds of very different chemical nature and with different aromatic descriptors, which will increase its aromatic complexity of these wines. Aroma sensory profile of Chelva wines was defined by higher intensity of fresh and peach aromas with notes citric, green apple, tropical fruit and sweet. This study showed that the Chelva grapes variety cultivated in La Mancha region present a great aroma potential and a complex sensory profile and can be considered a viable alternative to traditional grape varieties cultivated in this region for increasing the offer to the consumer.

Replication of PTPRC as genetic biomarker of response to TNF inhibitors in patients with rheumatoid arthritis

Genetic biomarkers could be useful for orienting treatment of patients with rheumatoid arthritis (RA), but none has been convincingly validated yet. Putative biomarkers include 14 single nucleotide polymorphisms that have shown association with response to TNF inhibitors (TNFi) in candidate gene studies and that we assayed here in 755 RA patients. Three of them, in the PTPRC, IL10 and CHUK genes, were significantly associated with response to TNFi. The most significant result was obtained with rs10919563 in PTPRC, which is a confirmed RA susceptibility locus. Its RA risk allele was associated with improved response (B=0.33, P=0.006). This is the second independent replication of this biomarker (P=9.08 × 10(-8) in the combined 3003 RA patients). In this way, PTPRC has become the most replicated genetic biomarker of response to TNFi. In addition, the positive but weaker replication of IL10 and CHUK should stimulate further validation studies.

Enhancement of phytosterols, taraxasterol and induction of extracellular pathogenesis-related proteins in cell cultures of Solanum lycopersicum cv Micro-Tom elicited with cyclodextrins and methyl jasmonate

Suspension-cultured cells of Solanum lycopersicum cv Micro-Tom were used to evaluate the effect of methyl jasmonate and cyclodextrins, separately or in combination, on the induction of defense responses. An extracellular accumulation of two sterols (isofucosterol and β-sitosterol) and taraxasterol, a common tomato fruit cuticular triterpene, were observed. Their levels were higher in Micro-Tom tomato suspension cultured cells elicited with cyclodextrins than in control and methyl jasmonate-treated cells. Also, their accumulation profiles during the cell growth phase were markedly different. The most striking feature in response to cyclodextrin treatments was the observed enhancement of taraxasterol accumulation. Likewise, the exogenous application of methyl jasmonate and cyclodextrins induced the accumulation of pathogenesis-related proteins. Analysis of the extracellular proteome showed the presence of amino acid sequences homologous to pathogenesis-related 1 and 5 proteins, a cationic peroxidase and a biotic cell death-associated protein, which suggests that methyl jasmonate and cyclodextrins could play a role in mediating defense-related gene product expression in S. lycopersicum cv Micro-Tom.

Nonsuppressed ion chromatographic determination of total calcium in milk

A novel approach for measuring calcium in milk by the use of high performance nonsuppressed ion chromatography is proposed. Total calcium as well as the calcium present in the colloidal and salt state in milk can be quantified. Because the presence of citrate in the milk serum interferes with the measurement of calcium by the conductivity detector, the free and chelated calcium can also be distinguished. By using a sample preparation procedure using Amberlite resin (Fluka, Steinheim, Germany), the amount of soluble calcium in milk can be determined. Because the quantification of calcium in milk and milk derivatives is becoming increasingly important in order to understand the functionality of the milk proteins, better methods need to be developed to determine, with a high level of accuracy, the amount of calcium present in milk in various forms.

Induction of sesquiterpenes, phytoesterols and extracellular pathogenesis-related proteins in elicited cell cultures of Capsicum annuum

Capsicum annuum suspension cell cultures were used to evaluate the effect of cyclodextrins and methyl jasmonate as elicitors of defence responses. The induced defence responses included the accumulation of sesquiterpenes and phytosterols and the activation of pathogenesis-related proteins, leading to reinforcement and modification of the cell wall architecture during elicitation and protection cells against biotic stress. The results showed that the addition of both cyclodextrins and methyl jasmonate induced the biosynthesis of two sesquiterpenes, aromadendrene and solavetivone. This response was clearly synergistic since the increase in the levels of these compounds was much greater in the presence of both elicitors than when they were used separately. The biosynthesis of phytosterols was also induced in the combined treatment, as the result of an additive effect. Likewise, the exogenous application of methyl jasmonate induced the accumulation of pathogenesis-related proteins. The analysis of the extracellular proteome showed the presence of amino acid sequences homologous to PR1 and 4, NtPRp27-like proteins and class I chitinases, peroxidases and the hydrolytic enzymes LEXYL1 and 2, arabinosidases, pectinases, nectarin IV and leucin-rich repeat protein, which suggests that methyl jasmonate plays a role in mediating defence-related gene product expression in C. annuum. Apart from these methyl jamonate-induced proteins, other PR proteins were found in both the control and elicited cell cultures of C. annuum. These included class IV chitinases, beta-1,3-glucanases, thaumatin-like proteins and peroxidases, suggesting that their expression is mainly constitutive since they are involved in growth, development and defence processes.

Rheological properties of rennet gels containing milk protein concentrates

Different milk protein concentrates (MPC), with protein concentrations of 56, 70, and 90%, were dispersed in water under different treatments (hydration, shear, heat, and overnight storage at 4 degrees C), as well as in a combination of all the treatments in a factorial design. The particle size distribution of the dispersions was then measured to determine the optimal conditions for the dispersion. Heating at 60 degrees C for 30 min with 5 min of shear was chosen as the best condition to dissolve MPC powders. The samples were also characterized for composition, presence of protein aggregates, and ratio of calcium to protein. The total calcium present in MPC increased with increasing concentration of protein; however, the total calcium-to-protein ratio was lower in MPC90 than in MPC56 and MPC70. The level of whey protein denaturation, the presence of kappa-casein-whey protein aggregates in the supernatant after centrifugation, and the amount of caseins dissociated from the micelle increased as the protein concentration in the powder increased. The total amount of casein macropeptide released was lower in samples from powders with a higher protein concentration than for MPC56 or the skim milk control. The gelation behavior of reconstituted MPC was tested in systems dispersed in water (5% protein) as well as in systems dispersed in skim milk (6% protein). The gelation time of MPC dispersions was considerably lower and the gel modulus was higher than those of reconstituted skim milk with the same protein concentration. When MPC dispersions were dialyzed against skim milk, a significant decrease in the gelation time and modulus were shown, with a complete loss of gelling functionality in MPC90 dispersed in water. This demonstrated that the ionic equilibrium was key to the functionality of MPC.

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.

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.

Changes in phenol content during strawberry (Fragariaxananassa, cv. Chandler) callus culture

Total soluble phenols, soluble flavanols, (+)-catechin, ferulic acid and 1-O-feruloyl-beta-d-glucose were analyzed during the development of a strawberry (Fragariaxananassa, cv. Chandler) callus culture. The time-course changes of the different phenols assayed were well correlated with callus growth and morphology. The changes in polyphenol oxidase (EC 1.10.3.1-2) and beta-glucosidase (EC 3.2.1.21) activities in the callus were also examined. The total phenol, soluble flavanols and (+)-catechin contents were high during the preexponential and exponential phases of growth. The subsequent decrease in (+)-catechin concentration coincided with high levels of polyphenol oxidase activity. The 1-O-feruloyl-beta-d-glucose content was highest as callus growth ceased, and its subsequent decrease was accompanied by the increased production of ferulic acid. This increase in ferulic acid was accompanied by an increase in beta-glucosidase activity. The ferulic acid content decreased at the end of culture, when callus growth had stopped and showed clear symptoms of senescence. This decrease in the ferulic acid concentration was accompanied by an increase in the levels of ferulic acid bound to cell wall components.

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.

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.

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.

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.

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.

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.

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.

Distribution of isoflavones in lupin hypocotyls. Possible control of cell wall peroxidase activity involved in lignification

The distribution of 4 key isoflavones (luteone, genistein, 2'-hydroxygenistein and wighteone) in lupin (Lupinus albus L. cv. multolupa) hypocotyls shows a gradient that diminishes from young to old tissues. A spatial gradient occurs within the hypocotyl, and a temporal gradient in both the outermost vascular and epidermal tissues. Not only does a gradient exist in respect to the quantity of isoflavones, but there is also a gradient in respect to the type of isoflavone. Thus, wighteone is mainly associated with the non-meristematic zones of the lupin hypocotyl. A close relationship was found between the distribution and the localization in the walls of phloem cells of both peroxidase (EC 1.11.1.7) and isoflavones. This observation suggests an in vivo peroxidase-isoflavone interconnection. In fact, lupin isoflavones are able to inhibit the peroxidase-catalyzed oxidation of the lignin precursor coniferyl alcohol, probably due to the co-oxidation of isoflavones in the reaction media. The results are discussed on the basis of a possible role for isoflavones in controlling cell wallperoxidase activity involved in the lignification of phloem cells.

Indole-3-methanol is the main product of the oxidation of indole-3-acetic acid catalyzed by two cytosolic basic isoperoxidases from Lupinus

The nature of the products of the auxin catabolism mediated by both basic and acidic isoperoxidases has been studied. While indole-3-methanol is only a minor product of the oxidation of indole-3-acetic acid catalyzed by extracellular acidic isoperoxidases, it is the only product of the oxidation of indole-3-acetic acid catalyzed by two cytosolic basic isoperoxidases (EC 1.11.1.7) from lupin (Lupinus albus L.) hypocotyls. The putative indole-3-methanol formed by these latter isoperoxidases was isolated and then characterized by mass spectrometry and (1)H-nuclear magnetic resonance spectrometry. These results are discussed with respect to the diversity and compartmentation of the catabolism of indole-3-acetic acid in plant tissues.