476 resultados para peach peroxidases


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S. B. Rosenhain

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Max Joseph

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mit Erl. von M. Lehmann.

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The physiological and molecular responses of ripe fruit to wounding were evaluated in two peach (Prunus persica) varieties ('Glohaven', GH, melting and 'BigTop', BT, slow melting nectarine) by comparing mesocarp samples from wedges (as in minimal processing) and whole fruit as the control. Slight differences between the two varieties were detected in terms of ethylene production, whereas total phenol and flavonoid concentrations, and PPO and POD enzyme activities showed a general increase in wounded GH but not in BT. This was associated with the better appearance of the BT wedges at the end of the experimental period (72 h). Microarray (genome-wide ?PEACH3.0) analysis revealed that a total number of 2218 genes were differentially expressed (p < 0.01, log2 fold change expression ratio >1 or <-1) in GH 24 h after wounding compared to the control. This number was much lower (1208) in BT. According to the enrichment analysis, cell wall, plasma membrane, response to stress, secondary metabolic processes, oxygen binding were the GO categories over-represented among the GH up-regulated genes, whereas plasma membrane and response to endogenous stimulus were the categories over-represented among the down-regulated genes. Only 32 genes showed a common expression trend in the two varieties 24 h after wounding, whereas a total of 512 genes (with highly represented transcription factors), displayed opposite behavior. Quantitative RT-PCR analysis confirmed the microarray data for 18 out of a total of 20 genes selected. Specific WRKY, AP2/ERF and HSP20 genes were markedly up-regulated in wounded GH, indicating the activation of regulatory and signaling mechanisms probably related to different hormone categories. Compared to BT, the expression of specific genes involved in phenylpropanoid and triterpenoid biosynthetic pathways showed a more pronounced induction in GH, highlighting the difference between the two peach varieties in terms of molecular responses to wounding in the mesocarp tissue.

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Experiments to evaluate the effect of in-season calcium (Ca) sprays on late-season peach (Prunus persica L. Batsch cv. Calrico) were carried out for a 2-year period. Calcium formulations (0.5% and 1.0% in 2008 and only 0.5% tested in 2009) supplied either as CaCl2 or Ca propionate in combination with two or three adjuvants (0.05% of the nonionic surfactants Tween 20 and Break Thru, and 0.5% carboxymethylcellulose, CMC) were sprayed four to five times over the growing season. Peach mesocarp and endocarp Ca concentrations were determined on a 15-day basis from the beginning of May until the end of June. Further tissue analyses were performed at harvest. A decreasing trend in fruit Ca concentrations over the growing season was always observed regardless of the Ca treatments. Both in 2008 and 2009, significant tissue Ca increments associated with the application of Ca-containing sprays in combination with adjuvants were only observed in June, which may be coincident with the period of pit hardening. In 2008, both at harvest and after cold storage, the total soluble-solids concentration (° Brix) of fruits supplied with Ca propionate (0.5% and 1.0% Ca) was always lower as compared to the rest of treatments. The application of multiple Ca-containing sprays increased firmness at harvest and after cold storage, especially when CaCl2 was the active ingredient used. Supplying the adjuvants Tween 20 and CMC increased fruit acidity both at harvest and after cold storage. Evaluation of the development of physiological disorders after cold storage (2 weeks at 0°C) indicated a lower susceptibility of Ca-treated fruits to internal browning. Fruits treated with multiple CaCl2-, CMC-, and Break Thru®-containing sprays during the growing season were significantly less prone to the development of chilling injuries as compared to untreated peaches.

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Increasing consumer dissatisfaction related with lack of ripeness in peach has been repeatedly reported since 1990 to the present day. There is thus, a great interest in improving the assessment of peach maturity, currently based on Magness Taylor firmness (destructive, highly variable, and time consuming) and colour (not reliable for highly coloured varieties). The present research studies as an alternative several non-destructive (ND) measurements, based on multispectral imaging, visible spectra, and low mass impact response. Their relationship with maturity, as well as the potential of their combination was studied. As a result, two rather independent (R2 = 0.3) groups of non-destructive measurements, chlorophyll related optical indexes and low mass impact (LMI) measurements, were identified. Optical measurements showed the best behaviour for assessing maturity at harvest, while LMI measurements reflected handling incidences, showing a promising potential to be used to control transport and postharvest handling.

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BACKGROUND: Pru p 3 is the major peach allergen and the most frequent cause of food allergy in adults in the Mediterranean area. Although its allergenicity is well characterized, its ability to generate a T-cell response is not completely known. OBJECTIVE: To investigate the influence of Pru p 3 allergen on dendritic cell (DC) maturation and specific T-cell response (T(H)1/T(H)2) in peach allergic patients. METHODS: Peach allergic patients (n = 11) and tolerant controls (n = 14) were included in the study. Monocyte-derived DC maturation after incubation with Pru p 3 was evaluated by the increase of maturational markers (CD80, CD86, and CD83) by flow cytometry. Lymphocyte proliferation was evaluated by coculturing monocyte-derived DCs and 5,6-carboxyfluorescein diacetate N-succinimidyl ester-stained lymphocytes with different concentrations of Pru p 3 (25, 10, and 1 ?g/mL) by flow cytometry and cytokine production. RESULTS: Pru p 3 induced a significant increase in the CD80, CD86, and CD83 expression on stimulated DCs from patients compared with controls. The lymphocyte proliferative response after Pru p 3 stimulation was also significantly higher along with an increase in interleukin 8 in patients compared with tolerant controls. CONCLUSION: Pru p 3 allergen induces changes in DC maturational status mainly in peach allergic patients. An increase in lymphocyte proliferative response accompanied with a different cytokine pattern was also observed compared with healthy controls.

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In a previous work, deduced amino acid sequences from twenty wheat peroxidase genes were assigned to seven groups designated as TaPrx108 to TaPrx114. Some of these apoplastic peroxidases have previously shown to play different roles in the plant defense responses to infection by the cereal cyst nematode Heterodera avenae. In the present study, PCR marker analysis using Sears’s aneuploid wheat lines cv. ‘Chinese Spring’ was used to locate four genes encoding peroxidase isozymes. The TaPrx111-A, TaPrx112-D and TaPrx113-F genes were located on the short arm of chromosome 2B and the TaPrx109-C on the long arm of chromosome 1B. These results would agree with the synteny between wheat and rice chromosomes previously established in other studies.

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Treatment of food allergy consists of the avoidance of the specific allergenic food. However, the possibility of cross-reactivity with other food sources makes this practice sometimes ineffective. The use of hypoallergenic molecules with the ability to stimulate T cells may be a promising tool for specific immunotherapy.

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Mechanical damage to fruits results from a combination of fruit properties and of damage inflicting effects by the handling equipment. Treatments were applied to fruits which affect mechanical damage susceptibility: precooling for stone fruits and degreening to citrus fruits. Laboratory tests (compression, impact, tumbling, abrasion) and field tests (damage in the handling lines) were applied to (3) peach, (2) apricot, (2) orange and (1) lemon varieties. Hydroor-air-cooling influence positively peach and apricot firmness and cause a significant reduction in: number of bruised fruits, and size of visible bruise, when combined with a low level of loading during handling. Degreening also affects the resistance of citrus fruits to handling, when compared to green fruits.

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The Physical Properties Laboratory (LPF) has been working on the improvement of fruit and vegetable grading lines since 1992'. The experience shows that the improvement of grading lines for decreasing mechanical damages has to be approached from two viewpoints: 1) machinery aggressiveness, and 2) fruit susceptibility. Machinery aggressiveness can be characterized as impact probability for different impact intensities assessed by means of electronic fruits (IS-100) 2,5 . On the other hand, bruise susceptibility can be determined using different laboratory tests. A recent study from LPF4 shows that damage may arise differently in pome and in stone fruits, since: a) pome fruits are mainly stress-susceptible, while stone fruits appear to be more deformation-susceptible, and b) bruise size may be a good predictor for bruise susceptibility in pome fruits while for stone fruits bruise probability is the most relevant characteristic of bruise susceptibility. Also, this study indicates the feasibility of predicting bruise probability using several mechanical and load characterization parameters. Despite the efforts to establish damage thresholds in peachess, no simulation models are currently available for predicting bruise occurrence in grading lines.

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Antecedentes: El potencial alergénico de las proteínas puede alterarse mediante modificaciones fisicoquímicas. El glutatión (GSH) es un agente reductor utilizado como antioxidante en productos alimentarios. Objetivo: Este estudio pretende caracterizar el plegamiento natural de las proteínas de melocotón y cuantificar la alergenicidad del alérgeno mayor del melocotón, Pru p 3, natural y reducido. Métodos: Para ello, se purificó Pru p 3 y se analizó su conformación mediante dicroismo circular (DC). Mediante el análisis con tiol fluorescente, se detectaron las proteínas reducidas en melocotones frescos. Pru p 3 reducido por GSH fue analizado mediante un ensayo in vitro de proliferación de células T e in vivo mediante prueba cutánea. Resultados: Pru p 3 reducido produjo reacciones variables en las pruebas cutáneas de los pacientes alérgicos a melocotón; sin embargo, su estabilidad a la digestión gastrointestinal fue similar a la de la forma natural. La respuesta proliferativa de las células mononucleares de los pacientes alérgicos frente a Pru p 3 reducido mostró una tendencia a ser inferior, mientras que la secreción de citocinas IFN?, IL5 e IL10 fue similar a la producida con la forma natural. La reducción alteró la unión de la IgE a Pru p 3 en un pool de sueros de pacientes alérgicos a melocotón. Conclusin: En conclusión, el glutatión es capaz de reducir Pru p 3, al menos de forma transitoria. En nuestro estudio, la reducción no afectó a la alergenicidad de Pru p 3, de forma que dicho aditivo no parece resolver el riesgo de alergia en pacientes alérgicos a melocotón. Palabras clave: GSH. Pru p 3. Alergia a melocotón. Agente reductor. Unión a IgE.

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Food allergies constitute a public health issue, with a reported overall estimated prevalence of 6% in Europe1 and Rosacea as the main allergenic fruits among adults.2 The commercial microarray ImmunoCAP ISAC 112 (Thermofisher, Uppsala, Sweden) is a semiquantitative and reproducible in vitro diagnostic tool used for the determination of specific IgE (sIgE).3 However, its panel of allergens does not have the best accuracy when it comes to determining fruit allergies in the Mediterranean area: the inclusion of the thaumatinlike protein (TLP) Pru p 2 or the apple lipid transfer protein (LTP) Mal d 3 has been proposed to improve the diagnosis of peach4 and apple5 allergies, respectively, in the Mediterranean basin. We sought to determine the usefulness of a component-resolved microarray for the diagnosis of peach and apple allergies in the Mediterranean area.