Fusarium tricinctum associated with Head Blight on barley in Argentina: pathogenicity and potential degradation of the different hordein fractions

Journal of Plant Diseases and Protection - The objective of the present work was to evaluate the pathogenicity of Fusarium tricinctum in barley and to determine the potential effects on grain...     

In vitro release of angiotensin-converting enzyme inhibitors, peroxyl-radical scavengers and antibacterial compounds by enzymatic hydrolysis of glycated gluten

The combined effect of gluten glycation and proteolysis on the release of compounds exhibiting in vitro angiotensin-converting enzyme (ACE) inhibitory, antioxidant and antibacterial activities was investigated. Model systems consisting of wheat gluten and glucose were heated at 120 °C for 45 min, 150 °C for 30 min and 220 °C for 30 min to produce various Maillard reaction products mimicking reactions occurring in bread crusts. Progress of the Maillard reaction was estimated through indirect measurement of Amadori compounds as 2-furoylmethyl-amino acids. Glycation was followed by digestion with Pronase E and ultrafiltration. The anti-hypertensive activity was measured as the ability to inhibit the activity of angiotensin I-converting enzyme involved in hypertension regulation. The Oxygen Radical Absorbance assay was used to measure the peroxyl radical scavenging capacity of the products and their effect on microbial growth of Escherichia coli ATCC 25922 and Staphlococcus aureus ATCC 25923 was also studied. Advanced products of the reaction enhanced the antioxidant and antibacterial properties of gluten hydrolysates and decreased the overall ACE inhibitory activity. Ultrafiltration provided a useful method for separating compounds (< 3000 Da) with ACE inhibitory activity and advanced Maillard reaction products (>3000 Da) which scavenged peroxyl radicals and inhibited the microbial growth.     

Solanum berthaultii Hawkes affects the digestive system,fat body and ovaries of the Colorado potato beetle

Ovarian development and fecundity of Colorado potato beetles reared on the resistant potato species,Solanum berthaultii were reduced compared to females reared on the susceptible potato,S. tuberosum. Striking changes in the appearance of the digestive tract and large quantities of undigested plant material in the midgut of females reared onS. berthaultii suggest that ovarian development might be impaired by poor nutritional quality ofS. berthaultii foliage. Alternatively, enlargement of the midgut by undigested plant material might physically limit ovarian development and subsequent fecundity. These results suggest that a major impact ofS. berthaultii on CPB performance occurs in the physiology of digestion and reproduction.     

Growth regulators,photoperiod, and flowering in potatoes

The effect of 25 ppm gibberellic acid (GA₃), 7,500 ppm Gapol^(R) (0.4% molybdate; 0.42% cobalt; 0.56% tungstate; 2.84% borax; 4 ppm indoleacetic acid; 4 ppm naphthyltalamic acid; and 2 ppm ethylenediaminetetraacetic acid) and of two photoperiods (12 and 18 h daily) on flowering of potato cv Marijke was studied under greenhouse conditions. GA³ specifically reduced the number of days required for flowering, and Gapol^(R), or long days, favored bud retention. When combined, only a slight additive effect was observed. In most cases spraying the products on plants subjected to long days resulted in an increase in the number of floral buds, but their attachment to the plant was mainly influenced by the presence of Gapol^(R).     

Thermotherapy and tissue culture for elimination of potato virus X (PVX) in Mexican potato cultivars resistant to late blight

Plants from 6 potato cultivars uniformly infected with potato virus X (PVX) were exposed to darkness and gradual temperature increases from 37 to 40 C, during a two-week period. This was followed by shoot tip culture to obtain virus free individuals. The procedure was effective in obtaining PVX-free propagation material from 4 of the 6 varieties. Differences were observed in the response of the cultivars to the heat and to thein vitro culture. At least one plant from every cultivar showed repeated negative serological reaction against PVX after the tissue culture regeneration, except Atzimba and Montsama. Tollocan and Murca were the most resistant to heat, developed better duringin vitro culture and resulted in the largest number of PVX-negative plants. Rosita was intermediate, and Juanita did not adapt to heat stress.     

Effects of Soy Protein and Calcium Levels on Mineral Bioaccessibility and Protein Digestibility from Enteral Formulas

Enteral formulas (EF) are complex food systems which have all the nutrients in their matrix for the complete human nourishment. However, there are components in EF which can interact with minerals, reducing their absorption, and thereof the EF nutritional quality. The effect of soy protein (SP) and Ca content on Fe, Zn, and Ca bioaccessibility and protein digestibility (%DP) was assessed using a response surface design in EF. Tested SP levels were 2.5–5.0 g/100 mL of total protein. Ca levels were adjusted with Ca citrate within a range between 50 and 100 mg/100 mL. SP content negatively influenced %DP and Fe, Zn and Ca bioaccessibility. As SP content increased, mineral bioaccessibility and %DP decreased, probably due to the increased levels of phytic acid and trypsin inhibitors from SP. Ca content only affected %DCa, which had a direct relationship with Ca levels, while did not affect Fe and Zn bioaccessibility or %DP. Since Ca citrate did not impair Fe and Zn bioaccessibility, it could be an appropriate Ca source for EF fortification.     

Relationships Between Chromosome 1B-encoded Glutenin Subunit Compositions and Bread-making Quality Characteristics of Some Durum Wheat (Triticum turgidum) Cultivars

The high and low M_r glutenin subunit compositions (controlled by the Glu-1 loci and the Glu-B3 locus, respectively) and the bread-making quality characteristics of 26 durum wheat (Triticum turgidum) genotypes were determined. The relationships between quality parameters and Glu-B1 and Glu-B3 controlled glutenin subunit composition were also investigated. The Glu-A1-controlled null allele was present in all the genotypes. High M_r subunits 20, 6 + 8 and 7 + 8 occurred in similar proportions in the cultivars analysed. The Glu-B3 low M_r allelic variants, LMW-1 and LMW-2, were both represented, with LMW-1 being present in lower proportion. Flour protein, SDS-sedimentation volume, dough strength (Alveograph W value), dough mixing time and bread loaf volume varied among the genotypes. Most samples had high Alveograph tenacity/extensibility (P/G) ratios, typical of tenacious gluten character. SDS-sedimentation volume, dough strength, dough mixing time and bread loaf volume were all interrelated. An association with flour protein content was observed only for mixing time, while the Alveograph tenacity/extensibility ratio was not correlated with the other parameters. Comparisons within the Glu-B1 and Glu-B3 loci indicated that the high M_r subunit 7 + 8 and the low M_r subunit LMW-2 had significantly greater beneficial effects on gluten strength and bread-making quality than the high M_r subunits 6 + 8 or 20 and the low M_r subunit LMW-1, respectively. High M_r subunit 6 + 8 had greater beneficial effects on quality than subunit 20.     

Antigenotoxicity and Antioxidant Activity of Acerola Fruit (Malpighia glabra L.) at Two Stages of Ripeness

Genotoxic and antigenotoxic effects of acerola fruit at two stages of ripeness were investigated using mice blood cells. The results show that no ripeness stage of acerola extracts presented any genotoxic potential to damage DNA (Comet assay) or cytotoxicity (MTT assay). When antigenotoxic activity was analyzed, unripe fruit presented higher DNA protection than ripe fruit (red color) extract. The antioxidant capacity of substances also showed that unripe samples inhibit the free radical DPPH more significantly than the ripe ones. The results about determination of compounds made using HPLC showed that unripe acerola presents higher levels of vitamin C as compared to ripe acerola. Thus, vitamin C and the complex mixture of nutrients of Malpighia glabra L., and especially its ripeness stages, influenced the interaction of the fruit extract with the DNA. Acerola is usually consumed when ripe (red fruit), although it is the green fruit (unripe) that has higher potential as beneficial to DNA, protecting it against oxidative stress.     

Molecular Analysis of Phytophthora infestans (Mont.) de Bary from Chapingo,Mexico. Phylogeographic Referential

An Andean origin of Phytophthora infestans was originally based on written records, and recently inferred from mitochondrial and nuclear gene genealogies, which emphasize a common South American origin of the European isolates, and absence of the I-b haplotype in Mexico (recently identified in Tlaxcala, Mexico). In order to compare such results, we sequenced the nuclear genes β-tubulin, Ras, and Intron Ras, and rDNA ITS regions in 24 P. infestans genotypes isolated, identified, and selected, during three crop growing cycles in Chapingo, Mexico. The pathogen showed homology and 100 % sequence similarities to the ones reported for the Andes and Europe β-tubulin, Ras, and Intron Ras genes. Results for the ITS region were inconclusive. The molecular oomycete similarities from the three geographical regions (South America, Europe, and Mexico), and the Mexican genotypes characteristics reported in the species supports the hypothesis of the location of P. infestans diversity and a center of dispersal in the central highlands of Mexico.     

Der Einfluss einer unterschiedlichen Düngung auf den Gehalt an Zitronensäure in Kartoffelknollen

Zusammenfassung Es wurde der Einfluss unterschiedlicher Düngergaben auf den Gehalt an Zitronens?ure in Knollen der Sorte ‘Radka’ geprüft, wobei die Probennahmen in den Phasen Vollblüte, im Abblühen und der Reife erfolgten. In reifen Knollen wurde ein relativ hoher Gehalt an Zitronens?ure bei einer Düngung von 120 kg N, 355 kg Ca und 30 kg Mg ha festgestellt. ?hnliche Ergebnisse wurden auch bei der Variante ohne Magnesium gefunden. Relativ hohe Gehalte an Zitronens?ure zeigte die Variante mit 60 kg Mg und 120 kg N ha-ohne Kalzium. Stark verminderte Gehalte an Zitronens?ure in reifen Knollen wurden dagegen bei den Varianten gefunden, die kein Calzium oder Magnesium erhalten hatten.