Repression of the 14-3-3 gene affects the amino acid and mineral composition of potato tubers

Recently, transgenic potato plants were created showing underexpression of the 20R isoform of the 14-3-3 protein. The transgenic plants grown in tissue culture showed a significant increase in nitrate reductase activity and a decrease in nitrate level. The transgenic line with the lowest 14-3-3 quantity was field-trialed (1997-2000) and analyzed. The reduction in the 14-3-3 protein level consistently resulted in a starch content increase and in an increase in the ratio of soluble sugars to starch in the tubers, although the latter was only barely visible. The determination of amino acid composition in the tubers showed a significant increase in methionine, proline, and arginine content and a slight but consistent increase in hydrophobic amino acid and lysine content in the cells of the transgenic potato plants. We also observed an increase in the crude protein content, from 19 to 22.1% of the control value in consecutive years. It is proposed that all of these changes might have resulted from the downregulation of nitrate reductase and sucrose phosphate synthase activities by 14-3-3, although other potential mechanisms cannot be excluded (e.g., an increase in enzyme protein level). 14-3-3-repressed transgenic plants showed a significant increase in calcium content in their tubers. It is thus proposed that a function of the isolated 14-3-3 isoform is in the control of amino acid synthesis and calcium metabolism. However, the mechanism of this control is as yet unknown.     

Leisure riding horses: research topics versus the needs of stakeholders

Horses intended for leisure riding do not undergo any selection and most often retired sports horses or defective horses are chosen, as a low selling price determines their purchase by a leisure riding center. Unfortunately, horses bought at low prices usually have low utility value, are difficult to handle, require a special or individual approach and do not provide satisfaction in riding. However, neither modern horse breeding nor scientific research address the need to breed horses for leisure activities. There is no clear definition of a model leisure horse and criteria or information for its selection are not readily available in scientific publications. A wide spectrum of research methods may be used to evaluate various performance traits in horses intended for leisure activities. The fact that the population of recreational horses and their riders outnumber sporting horses should attract the special attention of scientific research. Their utility traits need to be determined with modern technology and methods in the same way they are for sporting horses. Such a system of evaluation would be very helpful for riders.     

Effect of the lectin PHA on the feeding behavior of the grain aphid

The electrical penetration graph (EPG) method was used to quantify the effect of the lectin PHA (phytohemagglutinin) on the feeding behavior of the grain aphid Sitobion avenae F (Hemiptera: Aphididae). Addition of PHA to an artificial diet affected aphid probing behavior. In general, increasing concentrations of PHA in sucrose-agarose gels significantly reduced the number of aphid probes and extended their duration. Aphids feeding on the gels with lectin (without concentration 50 μg · cm⁻³) had a prolonged activity (EPG pattern C) that was corresponded to prolonged penetration of the epidermis and mesophyll for aphids feeding on plants. Such insects also showed a significant reduction in salivation and passive ingestion from gels and a reduction in the total number of gel penetrations. At concentrations ≤250 μg · cm⁻³, PHA reduced feeding behavior on gels, and the EPG data were interpreted to correspond with reduced salivation into phloem sieve elements (EPG pattern E1) and reduced ingestion of phloem sap (EPG pattern E2). PHA also delayed the onset of the first E1 and E2 patterns. At higher concentrations (≥500 μg · cm⁻³), PHA completely stopped salivation and passive ingestion from gels. Similarly, higher concentration of PHA strongly reduced activity on gels that corresponded to activity in xylem (EPG pattern G); high PHA delayed the onset of the first G pattern and reduced total time of pattern G activity.     

The effect of biostimulators on the content of crude oil and total protein in winter oilseed rape (Brassica napus L.) seeds

The objective of the study was to determine the effect of the experimental factors on the seed quality of three winter oilseed rape cultivars. The following factors were studied: I-three winter oilseed rape morphotypes: population, hybrid restored characterised by a semi-dwarf growth pattern, hybrid restored characterised by a conventional growth pattern; II-two sowing methods: a spacing of 22.5?cm, a spacing of 45.0?cm; III-four types of biostimulants: control-no biostimulants, the biostimulant Tytanit^®, Asahi^®SL, Silvit^®. Seed samples were subjected to chemical analysis to determine: crude oil, total protein and crude fibre. Natural stimulants of plant growth and development contributed to an increase in crude oil ranging from 7.4 to 9.5?g?kg^–1 d.m., on average, compared with control. The biostimulants applied did not affect total protein content which was, however, affected by meteorological conditions in individual study years as well as the genetic factor. Biostimulants increased crude fibre content compared with control.     

Anthocyanin composition in black, blue, pink, purple, and red cereal grains

Anthocyanin pigments from a wide variety of edible and ornamental black, blue, pink, purple, red, and white wheat, barley, corn, rice, and wild rice were identified and quantified to evaluate their potential as natural colorants or functional food ingredients. The total anthocyanin contents varied significantly and exhibited a range of 7-3276 microg/g. Some grains, such as red rice and black rice, contained a limited number of pigments, whereas others, such as blue, pink, purple, and red corns, had complex anthocyanin profiles. Of the 42 anthocyanin compounds observed, 9 were characterized by comparison of the spectroscopic and chromatographic properties with those of authentic standards. The remaining compounds were tentatively identified on the basis of spectroscopic properties and electrospray ionization mass spectra. The most abundant anthocyanins were cyanidin 3-glucoside in black and red rices and in blue, purple, and red corns, pelargonidin 3-glucoside in pink corn, and delphinidin 3-glucoside in blue wheat.     

Effect of sample preparation on the measurement of sugars, organic acids, and polyphenols in apple fruit by mid-infrared spectroscopy

The objectives of this study were (i) to test different conditions of freezing, thawing, and grinding during sample preparation and (ii) to evaluate the possibility of using mid-infrared spectroscopy for analyzing the composition of sugars, organic acids, and polyphenols in apples. Seven commercial apple cultivars were chosen for their large variability in composition (total polyphenols from 406 to 1033 mg kg(-1) fresh weight). The different conditions of sample preparation affected only the phenolic compounds and not sugars or organic acids. The regression models of the mid-infrared spectra showed a good ability to estimate sugar and organic acid contents (R(2) ≥ 0.96), except for citric acid. Good predictions were obtained for total phenolic, flavan-3-ols, and procyanidins (R(2) ≥ 0.94) provided oxidation was avoided during sample preparation. A rapid and simple procedure was then proposed for phenolic compounds using sodium fluoride during sample homogenization at ambient temperature and freeze-drying before spectra acquisition.     

Effects of Electron-Beam Radiation on Nutritional Parameters of Portuguese Chestnuts ( Castanea sativa Mill.)

Chestnuts are a widely consumed fruit around the world, with Portugal being the fourth biggest producer in Europe. Storage of these nuts is an important step during processing, and the most widely used fumigant was banned in the European Union under the Montreal Protocol because of its toxicity. Recently, radiation has been introduced as a cheap and clean conservation method. Previous studies of our research group proved that γ radiation had no negative effect on the nutritional value of chestnuts; in fact, storage time had a much bigger influence on the chestnut quality. In the present study, we report the effect of a less ionizing radiation, electron beam, with doses of 0, 0.5, 1, 3, and 6 kGy in the nutritional value of chestnuts (ash, energy, fatty acids, sugars, and tocopherols), previously stored at 4 °C for 0, 30, and 60 days. The storage time seemed to reduce fat and energetic values but reported a tendency for higher values of dry matter. With regard to fatty acids, there was a higher detected quantity of C20:2 in non-irradiated samples and four fatty acids were only detected in trace quantities (C6:0, C8:0, C10:0, and C12:0). γ-Tocopherol decreased during storage time but did not alter its quantity for all of the radiation doses (as like α-, β-, and δ-tocopherol); in fact, these compounds were present in higher concentrations in the irradiated samples. Sucrose and total sugars were lower in non-irradiated samples, and raffinose was only detected in irradiated samples. Electron-beam irradiation seems to be a suitable methodology, because the effects on chemical and nutritional composition are very low, while storage time seems to be quite important in chestnut deterioration.     

Defense strategies of pea embryo axes with different levels of sucrose to Fusarium oxysporum and Ascochyta pisi

The aim of this study was to compare the defense responses of embryo axes of Pisum sativum L. cv. Kwestor with different sucrose levels to pathogenic fungi, i.e. systemic acting Fusarium oxysporum f. sp. pisi and locally acting Ascochyta pisi. Embryo axes were cultured on Heller medium for 96 h. Four variants were compared: these included inoculated embryo axes cultured with or without 60 mM sucrose (+Si and −Si) and non-inoculated embryo axes cultured with or without 60 mM sucrose (+Sn and −Sn). After inoculation of the pea embryo axes with pathogenic fungi a generally higher concentration of free radicals was detected by electron paramagnetic resonance (EPR), in comparison to non-inoculated embryo axes. The inoculation with F. oxysporum caused stronger generation of free radicals in −Si than in +Si embryo axes. A different response was observed after inoculation with A. pisi; starting from 48 h, the concentration of free radicals in +Si axes was found to be 1.5 times higher than in −Si embryo axes. The values of spectroscopic splitting coefficients for these radicals suggest that they are semiquinone radicals. The EPR method also revealed Mn²⁺ ion accumulation after 24 h of culture. Over time, high levels of these ions were recorded in +Si embryo axes inoculated with F. oxysporum, while in +Si embryo axes inoculated with A. pisi they decreased. Up to 48 h after inoculation with the pathogenic fungi, Mn²⁺ ion levels were higher in +Si embryo axes than in +Sn axes. The activity of superoxide dismutase (SOD, EC 1.15.1.1) increased in +Si embryo axes up to 72 h after inoculation with pathogenic fungi; however, it was generally lower than in +Sn axes. Catalase activity (CAT, EC 1.11.1.6) increased up to 72 h after inoculation with F. oxysporum and the values were higher than in the non-inoculated tissue. Especially high activity of this enzyme was noted in −Si embryo axes after inoculation with either F. oxysporum or A. pisi. Peroxidase activity (POX, EC 1.11.1.7) towards pyrogallol in embryo axes increased during culture; however, it was lower or similar to that in non-inoculated embryo axes. SOD, CAT and POX zymograms showed that the synthesis of new isoforms was induced after inoculation with pathogenic fungi. Peroxidase isozymes detected by the reaction with diaminobenzidine in native PAGE were intensely stained in +Si embryo axes after inoculation with pathogenic fungi. Respiratory activity of the inoculated tissues was considerably higher than in non-inoculated tissues. The respiration rate was generally much higher in +Si than in −Si embryo axes. Growth of −Si embryo axes was more significantly retarded as a consequence of inoculation than that of +Si embryo axes.These results indicate that, depending on the manner of influence of a pathogenic fungus, both similar and differing defensive strategies may be initiated and a raised sugar levels in pea tissues limit the development of F. oxysporum and A. pisi.     

Effect of Replacing Cocoa Powder by Carob Powder in the Muffins on Sensory and Physicochemical Properties

The increasing demand for cocoa and search for ingredients rich in bioactive compounds encouraged us to investigate the possibility of replacing it by carob powder in the muffins containing soy beans, sesame oil and flaxseeds. There was 5% addition of carob or cocoa powder to the individual doughs. The muffins with the addition of carob were characterized by improved antiradical activity (by 36% - 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) method, by 83% - 2,2-diphenyl-1-picrylhydrazyl (DPPH) method), higher content of genistein (18%) and total phytosterols (17%) in the dry mass. The color differences in the carob muffins crusts were not perceptible by consumers (ΔE?=?0.70 for crust, ΔE?=?5.6 for crumb) and their taste was found to be less bitter and sweeter than the taste of cocoa muffins. Moreover, the addition of carob powder as well as cocoa powder resulted in good sensory quality. The high content of phytosterols, genistein and improved antiradical properties proved carob to be a source of bioactive compounds. The results show that carob powder may be used as valuable alternative muffin ingredient to cocoa.