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Comparative degradation of [14C]-2,4-dichlorophenoxyacetic acid in wheat and potato after Foliar application and in wheat, radish, lettuce, and apple after soil application.

The fate of 2,4-dichlorophenoxyacetic acid (2,4-D) applied foliarly as the 2-ethylhexyl ester (EHE) to wheat and potatoes, to the soil as the dimethylamine (DMA) salt under apple tree canopies, and preplant as the free acid for wheat, lettuce, and radish was studied to evaluate metabolic pathways. Crop fractions analyzed for (14)C residues included wheat forage, straw, and grain; potato vine and tubers; and apple fruit. The primary metabolic pathway for foliar application in wheat is ester hydrolysis followed by the formation of base-labile 2,4-D conjugates. A less significant pathway for 2,4-D in wheat was ring hydroxylation to give NIH-shift products 2,5-dichloro-4-hydroxyphenoxyacetic acid (4-OH-2,5-D), 4-OH-2,3-D, and 5-OH-2,4-D both free and as acid-labile conjugates. The primary metabolic pathway in potato was again ester hydrolysis. 2,4-D acid was further transformed to 4-chlorophenoxyacetic acid and 4-OH-2,5-D. For the soil applications, (14)C residues in the crops were low, and characterization of the (14)C residues indicated association with or incorporation into the biochemical matrix of the tissue. The degradative pathways observed in wheat are similar to those characterized in other intact plant studies but differ from those in studies in wheat cell suspension culture in that no amino acid conjugates were observed.

2,4-Dichlorophenoxyacetic Acid↗

Ileal starch digestibility in growing broiler chickens fed on a wheat-based diet is improved by mash feeding, dilution with cellulose or whole wheat inclusion.

1. An experiment was conducted to study causes of low ileal starch digestibilities when broiler chickens were fed on wheat-based diets. Each of 5 cold-pelleted diets containing 771 g/kg DM wheat and one cold-pelleted diet containing 694 g/kg DM wheat were fed to 24 male broiler chickens in 8 cages from 10 to 21 d of age. 2. Feed intake and weight gain were significantly reduced when the wheat diet was crushed and fed in a mash form. 3. Ileal starch digestibility increased significantly from 0.79 to 0.95, 0.93 and 0.91, respectively, when the diet was crushed and fed in a mash form, was diluted with cellulose prior to pelleting, or when parts of the wheat were fed as whole grains. Correspondingly, random variation between individual birds was reduced. 4. These results indicate that an overload of wheat starch in the digestive tract may be the cause of poor digestibility for some broilers in a flock. Grinding of the wheat may also influence starch digestibility.

Animal Feed↗

Safety of Oxygreen, an ozone treatment on wheat grains. Part 1. A four-week toxicity study in rats by dietary administration of treated wheat.

The Oxygreen process is a new treatment approved by The French Food Safety Authority (AFSSA) as a processing aid for flour quality improvement, based on treatment by ozone, in a closed sequential batch reactor. This treatment takes place in the classical milling sequence, after the grain-cleaning step and before milling. The Oxygreen process could also be used for its properties in wheat grain decontamination (insects, fungi, bacteria, mycotoxins, storage insecticides residues). The aim of this study was to determine if Oxygreen treatment could induce in the grain the formation of processing-related substances, able to provoke adverse effects, after ingestion of the wheat and/or derived products, and to establish the safety of the Oxygreen process for animals and consumers. A four-week toxicity study, according to OECD guideline No. 407, was performed on Dark agouti rats fed exclusively with wheat grains, treated or untreated with Oxygreen. Clinical, haematological, blood biochemical, urinary and histopathological parameters were investigated during the study. The few modifications observed in animals given treated wheat were an increase of rectal temperature in females, a slight decrease of calcium concentration in males and slight decrease of certain blood cell number without clinical significances. This work shows that wheat treated by Oxygreen does not induce adverse effects in Dark agouti rats after oral administration. Therefore wheat and derived products from wheat, after Oxygreen treatment on grain, could be considered as safe for the consumer.

Animals↗

Evaluation of broiler performance when fed Roundup-Ready wheat (event MON 71800), control, and commercial wheat varieties.

We evaluated the nutritional value of broiler diets containing approximately 40% wheat grain from Roundup Ready wheat (MON 71800), its similar nontransgenic control (MON 71900), or reference commercial wheat varieties. The feeding trial lasted 40 d, and each treatment consisted of 10 replicates of 1-d-old Ross 308 broilers (5 pens of males and 5 pens of females). Each pen contained 12 birds, and at d 13 birds were randomly removed until 9 birds remained. Body weight and feed intake were measured on pen basis at 40 d. At d 41, four broilers per pen were slaughtered. The carcasses were dissected, and cut-up yields were determined. Dry matter, protein, and fat contents of breast meat were determined. The data were analyzed by an ANOVA procedure. The BW and feed conversion at d 40 averaged 2,450 g and 1.52, respectively. There were no significant treatment x sex interactions, except for evisceration yield with significant differences (P < 0.05) in yield between birds fed 2 commercial wheat varieties. Data for final BW, feed conversion, carcass yield, and breast meat were not statistically different (P < 0.05) between broilers fed MON 71800 or MON 71900 or the population of birds fed commercial wheat varieties, except a lower carcass yield at d 41 for birds fed the nontransgenic control wheat. Thus MON 71800 was nutritionally equivalent to nongenetically modified wheat varieties when fed to broilers.

Animal Feed↗

Heteroplasmy and paternally oriented shift of the organellar DNA composition in barley-wheat hybrids during backcrosses with wheat parents.

Mitochondrial (mt) and chloroplast (ct) genome inheritance was studied in barley-wheat hybrids, as were their progenies obtained from backcrosses with different common wheat cultivars, by monitoring the composition of 4 mtDNA (coxI, a 5'-flanking region of cob, nad3-orf156, and 5'-upstream region of 18S/5S) and 2 ctDNA (simple-sequence repeat locus downstream of trnS and a 3'-flanking region of rbcL) loci. In male sterile F1 and BC1 plants, maternal barley mtDNA fragments were mainly detected and very low levels of paternal wheat fragments were occasionally detected by PCR in coxI, a 5'-flanking region of cob and nad3-orf156, whereas a 5'-upstream region of 18S/5S showed clear heteroplasmy, containing both maternal and paternal copies, with maternal copies prevailing. Plants showing such heteroplasmic mtDNA composition remained either semisterile or became completely sterile in the later backcross generations. Only maternal ctDNA copies were detected in these plants. In 3 stable, self-fertile, and vigourous lines obtained in the advanced backcross generations and possessing recombinant wheat nuclear genome, however, only mt- and ctDNA copies of wheat parents were detected; thus, the original alloplasmic condition appeared to be lost. Our results suggest that transmission followed by selective replication of the paternal wheat organellar DNA leads to a paternally oriented shift of the organellar DNA composition in barley-wheat hybrids, which correlates with the restoration of fertility and plant vigour. These 2 processes seem to be related to nucleocytoplasmic compatibility and to be under the control of the nuclear genome composition.

Chimera↗

Identification of allergen fractions of wheat flour responsible for anaphylactic reactions to wheat products in infants and young children.

Wheat is a food allergen which occasionally causes anaphylactic reactions exclusively in young children. There is very little knowledge of the clinical outcome in cases of food-related anaphylaxis and the differences in the allergenic protein components of food involved, comparing individuals who have suffered from an anaphylactic reaction with other individuals. The objectives of the present study were to examine the clinical features of 7 young children who had experienced anaphylactic reactions after ingesting wheat flour-containing products, and to analyze the allergens in wheat flour responsible for the anaphylactic symptoms. We measured the total IgE levels and the levels of IgE antibodies specific to wheat flour and performed IgE immunoblotting, comparing the sera from these children with sera from patients with atopic dermatitis. All sera from children who had experienced anaphylactic reactions were found to be positive for IgE specific to wheat. IgE immunoblotting revealed that 3 of these 7 children had sera showing reactivity to components of the salt-soluble protein fraction (16, 35--67 and 94 kD) and salt-insoluble protein-containing fraction (16, 38 and 70 kD) and 4 had no sera showing reactivity to components of the salt-soluble fraction. Patients with atopic dermatitis showed similar staining patterns. Various proteins in wheat flour could be allergens responsible for anaphylaxis and atopic dermatitis in infants or young children. Our findings suggest that these two clinically diverse allergic diseases do not necessarily represent responses to different allergenic proteins of wheat.

Allergens↗

Lysine-fortified wheat flour improves the nutritional and immunological status of wheat-eating families in northern China.

The purpose of this study was to determine the impact of the fortification of wheat flour with lysine on selected health indicators among farm families obtaining 58% to 67% of their dietary protein from wheat. A man, a woman, and a child aged 5 to 12 years were studied from each of 88 families in a village near Huixian City, Henan Province, China. Half of the families received wheat flour fortified with 3 g of lysine per kilogram for three months, and the other half received wheat flour without fortification. The results showed a significantly greater gain in the height and weight of children receiving lysine-fortified wheat flour. Hemoglobin values were not affected. The mean prealbumin values of adult men and women were higher in those receiving lysine. The numbers of CD3 T cells increased significantly in women and children, as did the complement fraction C3 and IgG in men, IgA in women, and IgG, IgA, IgM, and C3 in children. These results indicate that lysine fortification of wheat flour can significantly improve some indicators of the nutritional status and immune function of family members consuming a wheat-based diet.

Adult↗

Specific genetic markers for wheat, spelt, and four wild relatives: comparison of isozymes, RAPDs, and wheat microsatellites.

Three types of markers-isozymes, RAPDs (random amplified polymorphic DNAs), and wheat microsatellites- were tested on wheat, spelt, and four wild wheat relatives (Aegilops cylindrica, Elymus caninus, Hordeum marinum, and Agropyron junceum). The aim was to evaluate their capability to provide specific markers for differentiation of the cultivated and wild species. The markers were set up for subsequent detection of hybrids and introgression of wheat DNA into wild relatives. All markers allowed differentiation of the cultivated from the wild species. Wheat microsatellites were not amplified in all the wild relatives, whereas RAPDs and isozymes exhibited polymorphism for all species. The dendrograms obtained with RAPD and isozyme data separated Swiss wheat cultivars from those collected in Austria and England, while no difference was found between Swiss spelt and wheat. RAPD data provided a weak discrimination between English and Austrian E. caninus. The microsatellite-based dendrogram discriminated populations of Ae. cylindrica, but no clear separation of H. marinum from E. caninus was revealed. The similarity matrices based on the three different sets of data were strongly correlated. The highest value was recorded between the matrices based on RAPDs and isozymes (Mantel's test, r = 0.93). Correlations between the similarity matrix based on microsatellites and matrices based on RAPDs and isozymes were lower: 0.74 and 0.68, respectively. While microsatellites are very useful for comparisons of closely related accessions, they are less suitable for studies involving less-related taxa. Isozymes provide interesting markers for species differentiation, but their use seems less appropriate for studies of within-species genetic variation. RAPDs can produce a large set of markers, which can be used for the evaluation of both between- and within-species genetic variation, more rapidly and easily than isozymes and microsatellites.

Crosses, Genetic↗

Study of IgE antigenic relationships in hypersensitivity to hydrolyzed wheat proteins and wheat-dependent exercise-induced anaphylaxis.

BACKGROUND: Wheat is involved in different forms of respiratory, food and contact allergy. The IgE of patients generally reacts with various flour proteins. It is not known if antigenic relationships could explain some of these reactions and if proteins could be involved in different pathologies. METHODS: Two sera were selected as representative of patients with either wheat-dependent exercise-induced anaphylaxis (WDEIA) or hypersensitivity to hydrolyzed wheat proteins (HHWP). Their IgE specificity was studied with wheat, barley and rye proteins, using immunoblot, and immunoblot inhibition with recombinant gamma-3 hordein. This protein was chosen for its cross-reactivity with omega-5 gliadin, a major allergen in WDEIA. RESULTS: The IgE from both sera strongly reacted with natural and recombinant gamma-3 hordein but displayed different patterns of reactivity with wheat, barley and rye proteins. Those from the WDEIA patient showed expected reactions with omega-5 gliadin, gamma-35 and gamma-75 secalins, but also with wheat low-molecular-weight glutenin subunits (LMW-GS), and not with C hordeins. On the contrary, IgE from a HHWP patient reacted with C hordeins, various omega gliadins, and gamma-75 secalin, but very weakly with gamma-35 secalin and LMW-GS. Recombinant gamma-3 hordein inhibited strongly but not totally the WDEIA patient's IgE binding to prolamins. No such inhibition could be observed for the HHWP patient's IgE. CONCLUSIONS: At least part of the reactions of prolamins with the IgE from the WDEIA patient was due to antigenic homologies. The occurrence of cross-reacting carbohydrates was unlikely. These common IgE epitopes were not involved in the pathology of the HHWP patient.

Adult↗

Phosphorylation of wheat germ initiation factor 2 (eIF-2) by N-ethylmaleimide-treated wheat germ lysates and by purified casein kinase II does not affect the guanine nucleotide exchange on eIF-2.

Phosphorylation of the small subunit of eukaryotic initiation factor-2 (eIF-2 alpha) impairs protein synthesis in mammalian systems. It is not known, however, if a similar regulatory mechanism exists in plants. Previous reports indicate that one of the wheat germ eIF-2 subunits, the p40-41 doublet, is phosphorylated by heterologous eIF-2 alpha kinases. Here we report that phosphorylation of the small subunit in wheat germ eIF-2, p36, occurs in translating wheat germ lysates which are pretreated with N-ethylmaleimide (NEM) and dithiothreitol. Also, a purified sea star casein kinase II (CKII) phosphorylates the p41-42 doublet and p36 subunits of wheat germ eIF-2. While heme-regulated eIF-2 alpha kinase from reticulocyte lysates does not inhibit wheat germ protein synthesis, CKII and NEM are found to be inhibitory. To determine whether phosphorylation of the small subunit (p36) is the cause for protein synthesis inhibition, we have further studied the exchange of labeled GDP for unlabeled GDP in the preformed eIF-2. [3H]GDP complex in vitro in the presence of CKII and ATP. The GDP exchange in eIF-2.GDP complex can occur without the addition of any protein factor and the exchange reaction is marginally inhibited by CKII. A 0-70% ammonium sulfate cut fraction, prepared from NEM-treated wheat germ lysate, also does not inhibit the guanine nucleotide exchange reaction. These findings suggest that the protein synthesis inhibition in these cases is not mediated by eIF-2 phosphorylation.

Casein Kinase II↗

Transgenic wheat progeny resistant to powdery mildew generated by Agrobacterium inoculum to the basal portion of wheat seedling.

To improve the transformation efficiency of wheat (Triticum aestivum L.) mediated by Agrobacterium tumefaciens, we explored the possibility of employing the basal portion of wheat seedling (shoot apical meristem) as the explants. Three genotypes of wheat were transformed by A. tumefaciens carrying beta-1, 3-glucanase gene. After vernalization, the seeds to be transformed were germinated. When these seedlings grew up to 2 approximately 5 cm, their coleoptile and half of the cotyledon were cut out, and the basal portions were infected by A. tumefaciens. A total 27 T(0) transgenic plants were obtained, and the average transformation efficiency was as high as 9.82%. Evident segregation occurred in some of the T(1) plants, as was indicated by PCR and Southern blotting analysis. Investigation of the T(2) plants revealed that some transformed plants had higher resistance to powdery mildew than the controls. Northern blotting revealed that beta-1, 3-glucanase gene was normally expressed in the T(2) plants, which showed an increased resistance to powdery mildew. The results above indicate that the exogenous gene has been successfully integrated into the genome of wheat, transmitted and expressed in the transgenic progeny. From all the results above, it can be concluded that Agrobacterium inoculum to the basal portion of wheat seedling is a highly efficient and dependable transformation method. It can be developed into a practicable method for transfer of target gene into wheat.

Agrobacterium tumefaciens↗

Wheat Dof transcription factor WPBF interacts with TaQM and activates transcription of an alpha-gliadin gene during wheat seed development.

Wheat prolamin-box binding factor (WPBF), a DOF transcription factor previously was isolated from wheat endosperm and suggested to function as an activator of prolamin gene expression during seed development. In this study, we showed that WPBF is expressed in all wheat tissues analyzed, and a protein, TaQM, was identified from a wheat root cDNA library, to interact with the Dof domain of WPBF. The specific interaction between WPBF and TaQM was confirmed by pull-down assay and bimolecular fluorescence complementation (BiFC) experiment. The expression patterns of TaQM gene are similar with that of WPBF. The GST-WPBF expressed in bacteria binds the Prolamin box (PB) 5'-TGTAAAG-3', derived from the promoter region of a native alpha-gliadin gene encoding a storage protein. Transient expression experiments in co-transfected BY-2 protoplast cells demonstrated that WPBF trans-activated transcription from native alpha-gliadin promoter through binding to the intact PB. When WPBF and TaQM are co-transfected together the transcription activity of alpha-gliadin gene was six-fold higher than when WPBF was transfected alone. Furthermore, the promoter activities of WPBF gene were observed in the seeds and the vascular system of transgenic Arabidopsis, which was identical to the expression profiles of WPBF in wheat. Hence, we proposed that WPBF functions not only during wheat seed development but also during other growth and development processes.

Electrophoretic Mobility Shift Assay↗

The composition of grain and forage from glyphosate tolerant wheat MON 71800 is equivalent to that of conventional wheat (Triticum aestivum L.).

Glyphosate tolerant wheat MON 71800, simply referred to as MON 71800, contains a 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) protein from Agrobacterium sp. strain CP4 (CP4 EPSPS) that has a reduced affinity for glyphosate as compared to the endogenous plant EPSPS enzyme. The purpose of this work was to evaluate the compositional equivalence of MON 71800 to its nontransgenic parent as well as to conventional wheat varieties. The compositional assessment evaluated the levels of proximates, amino acids, fatty acids, minerals, vitamins, secondary metabolites, and antinutrients in wheat forage and grain grown during two field seasons across a total of eight sites in the United States and Canada. These data demonstrated that with respect to these important nutritional components, the forage and grain from MON 71800 were equivalent to those of its nontransgenic parent and commercial wheat varieties. These data, together with the previously established safety of the CP4 EPSPS protein, support the conclusion that glyphosate tolerant wheat MON 71800 is as safe and nutritious as commercial wheat varieties.

3-Phosphoshikimate 1-Carboxyvinyltransferase↗

Development of taxon-specific sequences of common wheat for the detection of genetically modified wheat.

Qualitative and quantitative Polymerase Chain Reaction (PCR) systems aimed at the specific detection and quantification of common wheat DNA are described. Many countries have issued regulations to label foods that include genetically modified organisms (GMOs). PCR technology is widely recognized as a reliable and useful technique for the qualitative and quantitative detection of GMOs. Detection methods are needed to amplify a target GM gene, and the amplified results should be compared with those of the corresponding taxon-specific reference gene to obtain reliable results. This paper describes the development of a specific DNA sequence in the waxy-D1 gene for common wheat (Triticum aestivum L.) and the design of a specific primer pair and TaqMan probe on the waxy-D1 gene for PCR analysis. The primers amplified a product (Wx012) of 102 bp. It is indicated that the Wx012 DNA sequence is specific to common wheat, showing homogeneity in qualitative PCR results and very similar quantification accuracy along 19 distantly related common wheat varieties. In Southern blot and real-time PCR analyses, this sequence showed either a single or a low number of copy genes. In addition, by qualitative and quantitative PCR using wx012 primers and a wx012-T probe, the limits of detection of the common wheat genome were found to be about 15 copies, and the reproducibility was reliable. In consequence, the PCR system using wx012 primers and wx012-T probe is considered to be suitable for use as a common wheat-specific taxon-specific reference gene in DNA analyses, including GMO tests.

Base Sequence↗

Lower glucose-dependent insulinotropic polypeptide (GIP) response but similar glucagon-like peptide 1 (GLP-1), glycaemic, and insulinaemic response to ancient wheat compared to modern wheat depends on processing.

OBJECTIVE: To test the hypothesis that bread made from the ancient wheat Einkorn (Triticum monococcum) reduces the insulin and glucose responses through modulation of the gastrointestinal responses of glucose-dependent insulinotrophic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) compared to the responses to bread of modern wheat (Triticum aestivum). DESIGN: The 3-h postprandial insulinaemic, glycaemic, GIP, and GLP-1 responses to bread made from Einkorn were compared to responses to a traditional Danish wheat loaf. The bread from Einkorn was prepared by 3 different processing methods: leavening with honey-salt added, leavening crushed whole grain, and conventional leavening with yeast added. Bread made from modern wheat was prepared by conventional leavening with yeast added. SUBJECTS: A total of 11 healthy young men. RESULTS: The postprandial GIP response was significantly (P<0.001) reduced by the Einkorn breads processed with honey-salt leavening and by using crushed whole grain bread compared to the yeast leavened bread made from modern wheat or from Einkorn. No significant differences were found in the responses of GLP-1, insulin or glucose. CONCLUSION: Einkorn honey-salt leavened and Einkorn whole grain bread elicit a reduced gastrointestinal response of GIP compared to conventional yeast bread. No differences were found in the glycaemic, insulinaemic and GLP-1 responses. Processing of starchy foods such as wheat may be a powerful tool to modify the postprandial GIP response.

Adult↗

Subgenome chromosome walking in wheat: a 450-kb physical contig in Triticum monococcum L. spans the Lr10 resistance locus in hexaploid wheat (Triticum aestivum L.).

For many agronomically important plant genes, only their position on a genetic map is known. In the absence of an efficient transposon tagging system, such genes have to be isolated by map-based cloning. In bread wheat Triticum aestivum, the genome is hexaploid, has a size of 1.6 x 10(10) bp, and contains more than 80% of repetitive sequences. So far, this genome complexity has not allowed chromosome walking and positional cloning. Here, we demonstrate that chromosome walking using bacterial artificial chromosome (BAC) clones is possible in the diploid wheat Triticum monococcum (A(m) genome). BAC end sequences were mostly repetitive and could not be used for the first walking step. New probes corresponding to rare low-copy sequences were efficiently identified by low-pass DNA sequencing of the BACs. Two walking steps resulted in a physical contig of 450 kb on chromosome 1A(m)S. Genetic mapping of the probes derived from the BAC contig demonstrated perfect colinearity between the physical map of T. monococcum and the genetic map of bread wheat on chromosome 1AS. The contig genetically spans the Lr10 leaf rust disease resistance locus in bread wheat, with 0.13 centimorgans corresponding to 300 kb between the closest flanking markers. Comparison of the genetic to physical distances has shown large variations within 350 kb of the contig. The physical contig can now be used for the isolation of the orthologous regions in bread wheat. Thus, subgenome chromosome walking in wheat can produce large physical contigs and saturate genomic regions to support positional cloning.

Chromosome Walking↗