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PubMed2005

Soft wheat instead of hard wheat in pelleted diets results in high starch digestibility in broiler chickens.

(1) The aim of the experiment was to re-examine variations in digestibilities of food components in 3-week-old broiler chickens fed on pelleted diets based on wheats differing in lipase activity and hardness. Fourteen wheat (Triticum aestivum) samples, each from a different cultivar, were included at 550 g/kg in 14 different diets given to male Ross broiler chicks from 7 d of age. The other main ingredients consisted of soyabean meal (353 g/kg) and rapeseed oil (55 g/kg). A 15th diet containing durum wheat (Triticum durum) was also tested. (2) Hardness of wheats (Triticum aestivum) varied between 14 (very soft) and 88 (very hard), and lipase activity of wheats varied from 1 to 13.1 (relative scale). No significant correlation was found between in vitro viscosities and other parameters such as hardness, particle size of wheat flours and lipase. Hardness was correlated with the mean particle size of wheat flours and durability of pellets. (3) Individual lipid digestibilities were negatively correlated with in vitro viscosities of wheats. (4) Individual starch digestibilities were negatively correlated with wheat hardness, particle size of wheat flour before pelleting, and pellet durability. The ratio of measured AME(N) to predicted AME(N) was also negatively correlated with wheat hardness. Simple regression calculation showed that a 100-point increase in wheat hardness resulted in a 3% decrease in the AME(N) value of diets. Multiple regression calculation showed the food/gain ratio (d 10 to d 21) to be positively related to wheat hardness and negatively related to pellet durability. (5) Wheat lipase activity was positively correlated with individual starch digestibility, which was the reverse of a result obtained in a previous experiment. Thus, wheat lipase activity did not seem consistent for predicting starch digestibility and AME(N) values. (6) Among all wheat samples, durum wheat showed the highest protein content and the lowest content of water-insoluble cell-wall. Starch digestibility of durum wheat tended to be lower than that of other wheats (0.916 vs 0.936). However, no significant difference in AME(N) was observed between the durum wheat sample and other wheats. (7) Gut morphometric data measured at d 24 did not show significant differences between dietary treatments.

Animal Feed↗
PubMed2005

Which cereal is a suitable substitute for wheat in children with wheat allergy?

Wheat is one of the main food allergens. It is among widely used cereals and there is an extensive cross-reaction between cereals. The aim of this study is to evaluate the extent to which cereals cross-react and to find the best substitute for wheat. Eighteen patients with definite diagnosis of type I hypersensitivity reactions to wheat enrolled in this study. Measurement of serum-specific IgE and skin prick test (SPT) for cereals flour (wheat, barley, oat, rye, rice and corn) and wheat bran was carried out. Also, open food challenge tests with available and conventional cereals in Iranian food culture (wheat, corn, rice and barley) were carried out. The SPTs were positive in 44.4% of patients for barley, 94.5% for wheat and 44-77% for other cereals. Positive serum-specific IgE was remarkable for wheat and barley and there was correlation between wheat and barley-specific IgE concentrations (r = 0.773 and p < 0.01). Corn serum-specific IgE was measured in 10 patients, which were positive in six of them. Of the patients, 55.5% had positive barley challenge tests, but all corn and rice challenge tests were negative. The best substitutes for wheat in wheat allergic patients are rice and corn. Regarding the correlation of wheat and barley serum-specific IgEs, there might be a high antigenic cross-reaction, therefore barley is not a good substitute for wheat and consuming barley needs a careful challenge test. Considering concordance of positive SPT to wheat flour and wheat bran, avoiding both of them is necessary in patients with wheat allergy.

Allergens↗
PubMed2006

Arabidopsis-rice-wheat gene orthologues for Na+ transport and transcript analysis in wheat-L. elongatum aneuploids under salt stress.

Lophopyrum elongatum is a wild relative of wheat that provides a source of novel genes for improvement of the salt tolerance of bread wheat. Improved Na(+) 'exclusion' is associated with salt tolerance in a wheat-L. elongatum amphiploid, in which a large proportion (ca. 50%) of the improved regulation of leaf Na(+) concentrations is controlled by chromosome 3E. In this study, genes that might control Na(+) accumulation, such as for transporters responsible for Na(+) entry (HKT1) and exit (SOS1) from cells, or compartmentalisation within vacuoles (NHX1, NHX5, AVP1, AVP2) in the model plant, Arabidopsis thaliana, were targeted for comparative analyses in wheat. Putative rice orthologues were identified and characterised as a means to bridge the large evolutionary distance between genomes from the model dicot and the more complex grass species. Wheat orthologues were identified through BLAST searching to identify either FL-cDNAs or ESTs and were subsequently used to design primers to amplify genomic DNA. The probable orthologous status of the wheat genes was confirmed through demonstration of similar intron-exon structure with their counterparts in Arabidopsis and rice. The majority of exons for Arabidopsis, rice and wheat orthologues of NHX1, NHX5 and SOS1 were conserved except for those at the amino and carboxy terminal ends. However, additional exons were identified in the predicted NHX1 and SOS1 genes of rice and wheat, as compared with Arabidopsis, indicating gene rearrangement events during evolution from a common ancestor. Nullisomic-tetrasomic, deletion and addition lines in wheat were used to assign gene sequences to chromosome regions in wheat and L. elongatum. Most sequences were assigned to homoeologous chromosomes, however, in some instances, such as for SOS1, genes were mapped to other unpredicted locations. Differential transcript abundance under salt stress indicated a complex pattern of expression for wheat orthologues that may regulate Na(+) accumulation in wheat lines containing chromosomes from L. elongatum. The identification of wheat orthologues to well characterized Arabidopsis genes, map locations and gene expression profiles increases our knowledge on the complex mechanisms regulating Na(+) transport in wheat and wheat-L. elongatum lines under salt stress.

Acclimatization↗
PubMed2001

IgE binding to soluble and insoluble wheat flour proteins in atopic and non-atopic patients suffering from gastrointestinal symptoms after wheat ingestion.

BACKGROUND: The involvement of IgE-mediated hypersensitivity reactions in the genesis of gastrointestinal symptoms after ingestion of foods containing wheat has been rarely reported. OBJECTIVE: To detect IgE specifically binding to wheat proteins in the sera of atopic and non-atopic patients suffering from gastrointestinal symptoms after ingestion of wheat and to evaluate the reliability of skin prick test and CAP in the diagnosis of food allergy to wheat. METHODS: The sera of patients (10 atopic and 10 non-atopic) previously diagnosed as suffering from irritable bowel syndrome and complaining of symptoms after wheat ingestion were analysed by immunoblotting for IgE binding to water/salt-soluble and insoluble wheat flour proteins. RESULTS: All the atopic patients and only one of the non-atopic patients were positive to wheat CAP. For the patients tested, skin prick test was positive for all the atopic patients and for only one of the non-atopic patients. However, immunoblotting experiments showed the presence of specific IgE to wheat proteins in all the patients. Ten out of 11 of the wheat CAP-positive patients had IgE binding to a soluble 16-kDa band, but the same band was recognized, in a slighter way, by only two out of nine of the wheat CAP-negative patients. Moreover, although almost all of the patients were negative in CAP testing with gluten, 19 out of 20 recognized protein bands belonging to the prolamin fraction. CONCLUSIONS: For the atopic patients the positivity to skin prick test and CAP to wheat was in accordance with the immunoblotting results and a food allergy to wheat could be diagnosed. In these patients a major allergen was a 16-kDa band corresponding to members of the cereal alpha-amylase/trypsin inhibitors protein family, the major allergens involved in baker's asthma. In the non-atopic patients the positive immunoblotting results contrasted with the responses of the allergologic tests, indicating that the allergenic wheat protein preparations currently used are of limited value in detecting specific IgE to wheat and that the fraction of irritable bowel syndrome (IBS) patients with food allergy may be larger than believed.

Adult↗
PubMed2001

Wheat omega-5 gliadin is a major allergen in children with immediate allergy to ingested wheat.

BACKGROUND: Sensitization to wheat by ingestion can lead to food allergy symptoms and wheat-dependent, exercise-induced anaphylaxis. Sensitization by inhalation causes bakers' asthma and rhinitis. Wheat allergens have been characterized at the molecular level in bakers' asthma and in wheat-dependent, exercise-induced anaphylaxis, in which omega-5 gliadin (Tri a 19) is a major allergen. However, little information is available regarding allergens responsible for hypersensitivity reactions to ingested wheat in children. OBJECTIVE: The aim of this study was to examine whether children with allergy to ingested wheat have IgE antibodies to omega-5 gliadin. METHODS: Sera were obtained from 40 children (mean age, 2.5 years; range, 0.7-8.2 years) with suspected wheat allergy who presented with atopic dermatitis and/or gastrointestinal and/or respiratory symptoms. Wheat allergy was diagnosed with open or double-blinded, placebo-controlled oral wheat challenge. Wheat omega-5 gliadin was purified by reversed-phase chromatography, and serum IgE antibodies to omega-5 gliadin were measured by means of ELISA. In vivo reactivity was studied by skin prick testing. Control sera were obtained from 22 children with no evidence of food allergies. RESULTS: In oral wheat challenge, 19 children (48%) reacted with immediate and 8 children (20%) with delayed hypersensitivity symptoms. Sixteen (84%) of the children with immediate symptoms had IgE antibodies to purified omega-5 gliadin in ELISA. In contrast, IgE antibodies to omega-5 gliadin were not detected in any of the children with delayed or negative challenge test results or in the control children. The diagnostic specificity and positive predictive value of omega-5 gliadin ELISA were each 100% for immediate challenge reactions. Skin prick testing with omega-5 gliadin was positive in 6 of 7 children with immediate challenge symptoms and negative in 2 children with delayed challenge symptoms. CONCLUSION: The results of this study show that omega-5 gliadin is a significant allergen in young children with immediate allergic reactions to ingested wheat. IgE testing with omega-5 gliadin could be used to reduce the need for oral wheat challenges in children.

Allergens↗
PubMed2004

Causes for improvement in nutritive value of broiler chicken diets with whole wheat instead of ground wheat.

1. Two experiments were conducted with broiler chicks to compare nutritive values of ground and whole wheat diets containing titanium oxide as indigestible marker. 2. In Experiment 1, a wheat and soy isolate based cold-pelleted diet, in which all the wheat was ground in a hammer mill to pass through a 3 mm sieve, was compared with a diet in which about half (375 g/kg) of the ground wheat was taken out of the diet and supplied as whole wheat mixed into the diet after pelleting. 3. In Experiment 2, a diet based on ground wheat and soy isolate which was pelleted after preconditioning (final temperature 81 degrees C) was compared with a diet in which 500 g of the ground wheat was replaced by whole wheat mixed into the diet before pelleting. 4. In Experiment 1, replacement of ground wheat with whole wheat increased apparent metabolisable energy (AME) content and starch digestibility measured at ileal as well as faecal level, while weight gain and feed conversion efficiency (FCE) were not affected. Jejunal chyme showed increased amylase activity and bile salt concentration. 5. In Experiment 2, replacement of ground wheat with whole wheat increased dry matter content as well as bile content of gizzard, and stimulated an increase in gizzard as well as pancreas weight. Jejunal amylase and bile concentrations were not significantly affected and neither were growth, FCE or AME. 6. Results from this experiment indicate that the improved feed value sometimes observed with whole wheat may be associated with modulation of digestive processes resulting in increased pancreas and liver secretions.

Amylases↗
PubMed2003

Inhibition of cholesterol absorption by phytosterol-replete wheat germ compared with phytosterol-depleted wheat germ.

BACKGROUND: Low-fat vegetable foods contain phytosterols, but it is not known whether they are in biologically active forms or whether their concentrations are high enough to reduce cholesterol absorption and favorably affect lipid metabolism. OBJECTIVE: The objective was to establish whether the selective removal of phytosterols from wheat germ would increase the cholesterol absorption measured from test meals composed of wheat germ muffins. DESIGN: Wheat germ, which has a high content of phytosterols relative to total fat, was chosen as a low-fat test food. Cholesterol absorption was measured 3 times in 10 subjects. Each test meal was a muffin containing 30 mg heptadeuterated cholesterol tracer and, in random order, 80 g original wheat germ containing 328 mg phytosterols, wheat germ from which phytosterols had been selectively extracted, or extracted wheat germ reconstituted with purified phytosterols. Changes in cholesterol absorption were monitored by the measurement of tracer enrichment of plasma cholesterol 4 and 5 d after each meal with the use of negative ion mass spectrometry. RESULTS: Tracer enrichment of plasma cholesterol was 42.8% higher after consumption of phytosterol-free wheat germ than after that of the original wheat germ (0.415 +/- 0.035 compared with 0.291 +/- 0.024 micro mol tracer/mmol cholesterol; P < 0.01). Tracer enrichment of plasma cholesterol was not significantly different between the wheat germ with extracted-and-reconstituted phytosterol (0.305 +/- 0.022 micro mol tracer/mmol cholesterol) and the original wheat germ. CONCLUSION: The efficiency of cholesterol absorption from test meals was substantially lower after consumption of original wheat germ than after consumption of phytosterol-free wheat germ, which suggests that endogenous phytosterols in wheat germ and possibly in other low-fat vegetable foods may have important effects on cholesterol absorption and metabolism that are independent of major nutrients.

Absorption↗
PubMed2005

Influence of three resistance sources in winter wheat derived from TAM 107 on yield response to Russian wheat aphid.

A study to determine yield response to the Russian wheat aphid, Diuraphis noxia (Mordvilko), was conducted during the 1997-1998 and 1998-1999 growing seasons at three eastern Colorado locations, Akron, Fort Collins, and Lamar, with three wheat lines containing either Russian wheat aphid-resistant Dn4 gene, Dn6 gene, or resistance derived from PI 222668, and TAM 107 as the susceptible control. Russian wheat aphids per tiller were greater on TAM 107 than the resistant wheat lines at the 10x infestation level at Fort Collins and Akron in 1999. Yield, seed weight, and number of seeds per spike for each wheat line were somewhat affected by Russian wheat aphid per tiller mainly at Fort Collins. The infested resistant wheat lines harbored fewer Russian wheat aphids and yielded more than the infested susceptible wheat lines. Wheat lines containing the Dn4, Dn6, and PI 222668 genes contain different levels of antibiosis or antixenosis and tolerance. Although differences existed among sites and resistance, there is a benefit to planting resistant wheat when there is a potential for Russian wheat aphid infestations.

Animals↗
PubMed2006

Growth of Pleurotus ostreatus on wheat straw and wheat-grain-based media: Biochemical aspects and preparation of mushroom inoculum.

Mycelial growth, intracellular activity of proteases, laccases and beta-1,3-glucanases, and cytoplasmic protein were evaluated in the vegetative phase of Pleurotus ostreatus grown on wheat straw and in wheat-grain-based media in Petri dishes and in bottles. The productivity of the wheat straw and wheat-grain-based spawn in cylindrical polyethylene bags containing 5 kg of chopped straw was also determined. We observed high activity of proteases and high content of intracellular protein in cultures grown on wheat straw. This suggests that the proteases are not secreted into the medium and that the protein is an important cellular reserve. On the contrary, cultures grown on wheat straw secreted laccases into the medium, which could be induced by this substrate. P. ostreatus grown on media prepared with a combination of wheat straw and wheat grain showed a high radial growth rate in Petri dishes and a high level of mycelial growth in bottles. The productivities of wheat straw and wheat-grain-based spawn were similar. Our results show that cheaper and more productive mushroom spawn can be prepared by developing the mycelium on wheat straw and wheat-grain-based substrates.

Agaricales↗
PubMed2004

Durum wheat as a candidate for the unknown female progenitor of bread wheat: an empirical study with a highly fertile F1 hybrid with Aegilops tauschii Coss.

Hexaploid bread wheat was derived from a hybrid cross between a cultivated form of tetraploid Triticum wheat (female progenitor) and a wild diploid species, Aegilops tauschii Coss. (male progenitor). This cross produced a fertile triploid F1 hybrid that set hexaploid seeds. The identity of the female progenitor is unknown, but various cultivated tetraploid Triticum wheats exist today. Genetic and archaeological evidence suggests that durum wheat ( T. turgidum ssp. durum) may be the female progenitor. In previous studies, however, F1 hybrids of durum wheat crossed with Ae. tauschii consistently had low levels of fertility. To establish an empirical basis for the theory of durum wheat being the female progenitor of bread wheat, we crossed a durum wheat cultivar that carries a gene for meiotic restitution with a line of Ae. tauschii. F1 hybrids were produced without using embryo rescue techniques. These triploid F1 hybrids were highly fertile and spontaneously set hexaploid F2 seeds at the average selfed seedset rate of 51.5%. To the best of our knowledge, this is the first example of the production of highly fertile F1 hybrids between durum wheat and Ae. tauschii. The F1 and F2 hybrids are both similar morphologically to bread wheat and have vigorous growth habits. Cytological analyses of F1 male gametogenesis showed that meiotic restitution is responsible for the high fertility of the triploid F1 hybrids. The implications of these findings for the origin of bread wheat are discussed.

Crops, Agricultural↗
PubMed2005

Comparison of Dn4- and Dn7-carrying spring wheat genotypes artificially infested with Russian wheat aphid (Homoptera: Aphididae) biotype 1.

Genetic resistance is a useful control strategy for managing Russian wheat aphid, Diuraphis noxia (Mordvilko), in wheat, Triticum aestivum L. In 2003, a Russian wheat aphid population (denoted as biotype 2) identified in Colorado was virulent to genotypes carrying the Dn4 Russian wheat aphid resistance gene, necessitating the rapid identification and deployment of new sources of resistance. Although the Dn7 gene had shown excellent resistance to Russian wheat aphid biotypes 1 and 2 in evaluations in the greenhouse, no information is available on the amount of protection provided by Dn7 under field conditions. The objective of this study was to compare the reaction of Dn4- and Dn7-carrying spring wheat genotypes under artificial infestation by Russian wheat aphid biotype 1 in the field. Irrigated field experiments were conducted in 2003 and 2004 in a split-split plot arrangement with six replications. The whole plot treatment was infestation level (control, 1x, and 10x Russian wheat aphids), and the subplot treatment was resistance source (Dn4- and Dn7-carrying genotypes). The sub-subplot treatment consisted of side-by-side planting of resistant and susceptible genotypes. The Dn4 subplot was significantly more damaged than the Dn7 subplot in 2003, but not in 2004. Interaction effects observed in 2004 suggested an advantage of Dn7 relative to Dn4 in terms of reduced Russian wheat aphid abundance and plant damage. Deployment of the Dn7 Russian wheat aphid resistance gene should provide protection in the field comparable with that provided by the Dn4 resistance gene for management of Russian wheat aphid biotype 1.

Animals↗
PubMed1987

Apparent digestibility of amino acids, gross energy and starch in corn, sorghum, wheat, barley, oat groats and wheat middlings for growing pigs.

Apparent nutrient digestibilities of yellow-dent corn, low-tannin sorghum, hard red winter wheat, barley, oat groats and wheat middlings were determined near the end of the small intestine and over the total digestive tract of growing pigs. Gross energy digestibilities for corn, sorghum and oat groats were similar; wheat had a slightly lower (P less than .05) digestibility, followed by barley (P less than .05), with wheat middlings being the least (P less than .05) digestible. About 7% of the gross energy in corn, sorghum, wheat and oat groats was digested in the large intestine, compared with 11% for barley and 17% for wheat middlings. The starch in all products was essentially 100% digestible by the end of the small intestine. Ileal amino acid digestibilities tended to be highest for wheat and oat groats, followed by corn, sorghum, barley and wheat middlings. The range in ileal digestibilities was 73.8 (sorghum) to 84.2% (wheat) for lysine, 69.6 (corn) to 81.4% (wheat) for tryptophan and 63.4 (wheat middlings) to 77.9% (oat groats) for threonine. Amino acid digestibilities determined over the total tract were generally higher than ileal digestibilities; however, values for lysine, methionine and phenylalanine were generally lower, indicating a net synthesis of these amino acids in the large intestine.

Amino Acids↗
PubMed1994

[Effect of hypoallergenic wheat (HAW-A1) on atopic dermatitis (AD) with wheat allergy, and its antigenic analysis using sera from patients with AD].

Wheat allergy has been suggested to be played an important role in the development and exacerbation of the severe type of atopic dermatitis (AD) in some cases. In this paper, we fractionated wheat antigenic proteins to salt-soluble and salt-insoluble fractions and assayed the IgE antibody titers against each fraction using AD patients' sera, indicating that the salt-soluble fraction has potential of major allergenicity. Then we prepared a hypoallergenic wheat flour (HAW-A1) by decomposition of the salt-soluble fraction using the salt solution washing procedure, and examined the hypoallergenicity of HAW-A1 in IgE-ELISA and IgE-immunoblotting with wheat-RAST positive AD's sera. The results were confirmed that most components of the salt-soluble proteins containing allergenic protein bands are decomposed from HAW-A1, and no IgE antibody titer could be detected in AD patients' sera. The next, the clinical usefulness of this hypoallergenic wheat (HAW-A1) was evaluated in 18 subjects with recalcitrant AD, who were suspected of having wheat allergy. In 15 of the 18 AD subjects tested, HAWN is very useful as a substitute of wheat foods, and in 11 of these patients has higher titers of IgE antibodies against the salt-soluble than salt-insoluble fractions which were extracted from regular wheat flour, and in 4 of these patients also have undetectable levels of IgE antibodies against either fraction. On the other hand, in 3 of 18 AD subjects who revealed positive reaction to HAWN ingestion as same as to regular wheat ingestion, and IgE antibodies to salt-insoluble proteins remaining in HAW-A1, were found. These results indicate that HAW-A1 is very useful as a substitute for wheat food, least in AD patients with wheat allergy who have high titers of IgE antibodies against the salt-soluble than salt-insoluble fractions, and who also have undetectable levels of IgE antibodies against the both fractions.

Adolescent↗
PubMed2002

A type 1 diabetes-related protein from wheat (Triticum aestivum). cDNA clone of a wheat storage globulin, Glb1, linked to islet damage.

The development of autoimmune type 1 diabetes involves complex interactions among several genes and environmental agents. Human patients with type 1 diabetes show an unusually high frequency of wheat gluten-sensitive enteropathy; T-cell response to wheat proteins is increased in some patients, and high concentrations of wheat antibodies in blood have been reported. In both major models of spontaneous type 1 diabetes, the BioBreeding (BB) rat and non-obese diabetic mouse, at least half of the cases are diet-related. In studies of BB rats fed defined semipurified diets, wheat gluten was the most potent diabetes-inducing protein source. A major limitation in understanding how wheat or other dietary antigens affect type 1 diabetes has been the difficulty in identifying specific diabetes-related dietary proteins. To address this issue, we probed a wheat cDNA expression library with polyclonal IgG antibodies from diabetic BB rats. Three clones were identified, and the intensity of antibody binding to one of them, WP5212, was strongly associated with pancreatic islet inflammation and damage. The WP5212 putative protein has high amino acid sequence homology with a wheat storage globulin, Glb1. Serum IgG antibodies from diabetic rats and humans recognized low molecular mass (33-46 kDa) wheat proteins. Furthermore, antibodies to Glb1 protein were found in serum from diabetic patients but not in age-, sex-, and HLA-DQ-matched controls. This study raises the possibility that in some individuals, type 1 diabetes may be induced by wheat proteins. Also, it provides a first candidate wheat protein that is not only antigenic in diabetic rats and human patients but is also closely linked with the autoimmune attack in the pancreas.

Amino Acid Sequence↗
PubMed2004

Comparative DNA sequence analysis of mapped wheat ESTs reveals the complexity of genome relationships between rice and wheat.

The use of DNA sequence-based comparative genomics for evolutionary studies and for transferring information from model species to related large-genome species has revolutionized molecular genetics and breeding strategies for improving those crops. Comparative sequence analysis methods can be used to cross-reference genes between species maps, enhance the resolution of comparative maps, study patterns of gene evolution, identify conserved regions of the genomes, and facilitate interspecies gene cloning. In this study, 5,780 Triticeae ESTs that have been physically mapped using wheat ( Triticum aestivum L.) deletion lines and segregating populations were compared using NCBI BLASTN to the first draft of the public rice ( Oryza sativa L.) genome sequence data from 3,280 ordered BAC/PAC clones. A rice genome view of the homoeologous wheat genome locations based on sequence analysis shows general similarity to the previously published comparative maps based on Southern analysis of RFLP. For most rice chromosomes there is a preponderance of wheat genes from one or two wheat chromosomes. The physical locations of non-conserved regions were not consistent across rice chromosomes. Some wheat ESTs with multiple wheat genome locations are associated with the non-conserved regions of similarity between rice and wheat. The inverse view, showing the relationship between the wheat deletion map and rice genomic sequence, revealed the breakdown of gene content and order at the resolution conferred by the physical chromosome deletions in the wheat genome. An average of 35% of the putative single copy genes that were mapped to the most conserved bins matched rice chromosomes other than the one that was most similar. This suggests that there has been an abundance of rearrangements, insertions, deletions, and duplications eroding the wheat-rice genome relationship that may complicate the use of rice as a model for cross-species transfer of information in non-conserved regions.

Chromosome Mapping↗
PubMed1997

Quantitative bronchial challenge tests with wheat flour dust administered by spinhaler: comparison with aqueous wheat flour extract inhalation.

BACKGROUND: Quantitative bronchial challenge tests with flour dust for the diagnosis of bakers' asthma may be performed by inhalation of flour delivered to the patient's respiratory tract by sophisticated equipment. OBJECTIVE: This study was carried out to assess the diagnostic value of bronchial challenge tests with flour dust inhalation from capsules administered by a Spinhaler (Fisons Inc., Loughborough, U.K.) and to compare this method quantitatively with bronchial challenge tests with a commercially available wheat flour extract. METHODS: A highly selected group of 36 bakers with work-related symptoms of rhinitis or asthma were referred to our department, a tertiary referral center, from 1992 to 1995. Thirty-four of the subjects and 10 atopic control subjects were included in this study. After the assessment of bronchial hyperresponsiveness on day 1, subjects were randomized to inhale an aqueous wheat flour extract at concentrations of 0.01, 0.1, 1, 10, and 100 mg/ml by tidal volume breathing for 10 minutes or to inhale wheat flour dust filled in capsules on days 2 and 3. One, two, and four capsules (maximum of 7 cumulative capsules) of flour dust were administered by a Spinhaler. In addition, skin prick tests were performed with a battery of environmental and occupational allergens. Total serum IgE and specific IgE to wheat flour were measured by standard procedures. RESULTS: Seventeen bakers and two control subjects demonstrated a positive skin test response to wheat flour (wheal > or = 3 mm). Fifteen bakers demonstrated a fall of 50% or more in specific airway conductance after inhalation of the commercial wheat flour extract, and 11 demonstrated such a fall in specific airway conductance after inhalation of wheat dust. Three control subjects had a positive bronchial challenge response to the extract, but dust inhalation from the capsule did not cause positive bronchial reactions in control subjects. When a 50% fall of specific airway conductance was used as criterion for a positive bronchial provocation test result, sensitivity for the extract or dust inhalation was 0.44 and 0.32, respectively, and specificity was 0.7 and 1.0, respectively. If only subjects with a positive skin test response to wheat flour were considered, sensitivity of both tests was 0.65. With more stringent criteria for the gold standard, there was a trend for a higher sensitivity but a lower specificity of the extract inhalation. Both methods were safe. CONCLUSION: The validity of bronchial challenge tests with wheat flour dust inhaled from Spinhaler capsules was superior to that of tests done with a commercially available aqueous wheat flour extract. The higher specificity of the Spinhaler method might be an advantage if bronchial challenge tests are used as confirmation tests.

Administration, Inhalation↗
PubMed2002

[Decomposition and nitrogen dynamics of wheat residues and impact on wheat growth stages].

N mineralisation and immobilisation were quantified in field conditions in the presence or in the absence of wheat residues. The incubation study was conducted in cylinders placed in microplots (no plants were grown in cylinders), and the rest of each microplot was sowed with the wheat crop (Triticum durum var. Massa). N mineralisation and immobilisation depend on the presence or the absence of wheat residues. In absence of residues, a linear model of regression was developed to follow the clear nitrogen mineralisation at different soil levels. Nitrogen mineralisation (mg kg-1), during the five months of wheat development, showed the following decreasing order: 0-15 cm (132.6) > 15-30 cm (120.6) > 30-45 cm (91.3). The mineralisation rate was 24.1, 22.9 and 18.9 mg kg-1 d-1 for 0-15, 15-30 and 30-45 cm levels, respectively. The supply of wheat residues resulted in a five months N immobilisation process. At level 0-15 cm the immobilisation (mg kg-1) showed the following decreasing order: (61.6) > (46.4) > (30.0) for the supply of wheat residues at seeding time, and 15 and 30 d before seeding respectively. At the other levels, the same decreasing order was recorded. The supply of 8 t ha-1 of wheat residues at seeding time, and 15 or 30 d before seeding, decreased the dry matter yield and N accumulation in wheat crop. In consequence, there was no synchronism between the nitrogen liberated by wheat residues decomposition and the wheat growth.

Hydrogen-Ion Concentration↗
PubMed2006

Wheat-kernel-associated endoxylanases consist of a majority of microbial and a minority of wheat endogenous endoxylanases.

The endoxylanases associated with wheat kernels consist of wheat endogenous endoxylanases on one hand and kernel-associated microbial endoxylanases on the other hand. Assessment of their presence, based on analysis of their enzymic activity, can be expected to be hampered by the presence in wheat of high levels of endogenous endoxylanase inhibitors, which are able to inhibit the wheat-kernel-associated microbial endoxylanases. On the basis of preliminary experiments aimed at clarifying the distribution of the wheat-associated endoxylanases, a method to estimate total endoxylanase activities in wheat kernels was developed. Extensive washing of wheat kernels with universal buffer of pH 8.0 provided near-quantitative separation of the microbial endoxylanases located on the surface of wheat kernels from the endogenous endoxylanases and endoxylanase inhibitors located in such kernels. The microbial or endogenous nature of the endoxylanases was confirmed by making use of the inhibition specificity of endoxylanase inhibitors. Determination of the endoxylanase activity in the washing liquid, corresponding to the microbial endoxylanase population, and the washed kernels, corresponding to the endogenous endoxylanase population, allowed estimation of the total endoxylanase activities associated with the wheat kernel. Results showed that microbial endoxylanases can account for over 90% of the total wheat-associated endoxylanase activity and that the latter can be at least 5 times higher than the apparent endoxylanase activity.

Endo-1,4-beta Xylanases↗