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Food allergy: the 10 common offenders.

The 10 chief offenders among food allergens are cow's milk, chocolate and cola (the kola nut family), corn, eggs, the pea family (chiefly peanut, which is not a nut), citrus fruits, tomato, wheat and other small grains, cinnamon and artificial food colors. Food allergy results in a remarkable variety of clinical syndromes. Diagnois rests on an elimination and challenge process. Treatment is avoidance. Desensitization does not work.

Animals↗

Genetic analysis of the species cytoplasm specific gene (scs d) derived from durum wheat.

The action of species cytoplasm specific (scs) gene(s) can be observed when a durum (Triticum turgidum L.) nucleus is placed in the Aegilops longissimum S. & M. cytoplasm. This alloplasmic combination, (lo) durum, results in nonviable progeny. A scs gene derived from T. timopheevii Zhuk. (scs(ti)) produced compatibility with the (lo) cytoplasm. The resulting hemizygous (lo) scs(ti)- durum line was male sterile and when crossed to normal durum produced a 1:1 ratio of plump, viable (PV) seeds with scs(ti) and shriveled inviable (SIV) seeds without scs(ti). In a systematic characterization of durum lines an unusual line was identified that when crossed to (lo) scs(ti)- produced all PV seeds. When planted these PV seeds segregated at a 1:1 ratio of normal vigor plants (NVPs) and low vigor plants (LVPs). The LVP senescence before full maturity. The NVPs were male sterile and when crossed to common durum lines resulted in all plump seeds that again segregated at a 1:1 ratio of NVPs to LVPs. The crosses of these NVPs to common durum lines resulted in a 1:1 ratio of PV to SIV seeds. This study was extended to 317 individuals segregating for scs(ti) and the new locus, derived from durum wheat (scs(d)), establishing the allelic relationship of these two genes.

Crosses, Genetic↗

Sensitization to common allergens and its association with allergic disorders at age 4 years: a whole population birth cohort study.

BACKGROUND: Atopy is defined as the genetic propensity to develop immunoglobulin E antibodies in response to exposure to allergens and assessed by skin prick test responses to common allergens. Although it is generally agreed that atopy is an important risk factor for allergic diseases such as asthma, rhinitis, and eczema, the extent to which atopy accounts for these diseases is controversial. OBJECTIVE: We aim to describe the prevalence of sensitization to common allergens and investigate the degree of association of atopy (as defined by positive skin prick test to 1 or more common allergens) to asthma, rhinitis, and eczema in a birth cohort at the age of 4 years. METHODS: A birth cohort of 1456 children was recruited over a 14-month period (1989-1990). These children have been seen previously at 1 and 2 years of age. At 4 years, 1218 children were reviewed and an interview was administered or postal questionnaire was completed for the presence of allergic diseases (asthma, rhinitis, and eczema). Additionally, in 981 children, skin prick tests with a battery of 12 common allergens were performed. Allergens were house dust mite (Dermatophagoides pteronyssimus), grass pollen mix, cat, dog, Alternaria alternata, Cladosporium herbarum, cow's milk, hen's egg, soya, cod, wheat, and peanut. A mean wheal diameter of at least 3 mm greater than the negative control was taken as positive. This analysis is confined to the 981 (67% of the original population) who also had skin prick tests to the standard battery. chi(2) tests were used to test the univariate association between each allergic disease and positive skin test. Multiple logistic regression analysis was performed to obtain the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the independent effect of sensitization to each allergen on allergic disease, adjusting for the effect of sensitization to other allergens. To ascertain how much of allergic disease is attributable to atopy, we estimated the population-attributable risk. This was calculated with the formula: P(R - 1) where R is the OR for the allergic disease under consideration and P is the proportion of atopy in children with that disease. RESULTS: Children who were skin prick-tested at 4 years were similar in most characteristics to the rest of the population, except that they had a higher prevalence of allergic disease. Allergic disorders (asthma, rhinitis, and eczema) were present in 276 (28.1%) of 981. One hundred ninety-two (19.6%) children were atopic (positive reaction to 1 or more allergens). Sensitization to inhalant allergens was relatively common (19.2%) as compared with food allergens (3.5%). House dust mite (11.9%), grass pollen (7.8%), and cat (5.8%) were the most common positive reactions. A test to the 4 most common allergens (house dust mite, grass pollen, cat, and A alternata) could detect 94% of the atopic children. Sensitization to the 4 most common allergens was strongly associated with the presence of allergic disorders. There was a graded effect with the potent allergens, such as house dust mite, having the greatest impact. For example, 50% of children sensitized to house dust mite had asthma as opposed to 44% sensitized to cat, 42% sensitized to grass pollen, and 32% sensitized to A alternata. Overall, 68.4% of children sensitized to house dust mite had asthma, eczema, and/or rhinitis. The respective figures for grass pollen, cat, and A alternata were 64.9%, 66.7%, and 57.4%. The proportion of children sensitized to cat was not higher in households with cat ownership (households with cats: 5.1% [19/374]; households without cats: 6.2% [36/580]; not significant [NS]). Similarly, no difference was seen in sensitization to dog in households with and without dogs (households with dogs: 1.8% [5/282]; households without dogs: 2.8% [19/673]; NS). Boys were atopic more often than girls at this age (male: 112 of 497 [22.5%] vs female: 80 of 484 [16.5%]; OR: 1.47, 95% CI: 1.07-2.02). Male preponderance was observed with most allergens, but this was statistically significant only for house dust mite (male: 75/497 [15.1%] vs female: 42/484 [8.7%]; OR: 1.87; CI: 1.25-2.79) and grass pollen (male: 51/497 [10.3%] vs female: 26/484 [5.4%]; OR: 2.01; CI: 1.23-3.29). An independent effect of allergen sensitization on asthma was observed only with house dust mite with an OR of 8.07 (CI: 4.60-14.14). The highest independent risk for rhinitis was sensitization to grass pollen (OR: 5.02; CI: 2.21-11.41), and for eczema, sensitization to peanut (OR: 4.65; CI: 1.02-21.34). The majority of children (98/192) were sensitized to >1 allergen. A graded effect was observed with the risk of allergic disease in the child increasing with the number of positive skin prick test reactions. This effect was consistent throughout the spectrum of allergic diseases (asthma, eczema, and rhinitis). (ABSTRACT TRUNCATED)

Allergens↗

A survey of ethnic foods for microbial quality and aflatoxin content.

A range of ethnic foods was examined for their microbiological content in relation to total viable counts (TVC) of aerobic bacteria, counts of presumptive coliforms, yeast and mould counts; presence of Salmonella spp., Listeria monocytogenes, Escherichia coli O157:H7 and Campylobacter spp.; total enumeration of Clostridium perfringens, Staphylococcus aureus and Bacillus spp.; identification of moulds and the presence of total aflatoxins. Samples, which included cereals, nuts, dried fruits, herbs and spices, were obtained from local retail outlets and distributors. It was established that three samples of pistachio nuts contained significant levels of aflatoxins. The concentration of total aflatoxins in these three nut samples ranged from 15 to 259 microg/kg of sample. Only two other samples contained trace amounts of aflatoxins, all other samples analysed were found to be free of any detectable level of aflatoxins. TVCs, coliform counts and yeast and mould counts varied widely depending on the matrix tested. Generally, rice, wheat and peanuts produced low counts whereas other nuts, gram flour and spices produced much higher counts. Cl. perfringens, Staph. aureus, and Bacillus spp. were common in spices, nuts and gram flour, however, Listeria monocytogenes was only detected in four samples and in no sample could Salmonella spp, E. coli O157:H7 or Campylobacter spp. be detected.

Aflatoxins↗

Larval Apis mellifera L. (Hymenoptera: Apidae) mortality after topical application of antibiotics and dusts.

Beekeepers apply various dusts to honey bee, Apis mellifera L., colonies to dislodge parasitic mites and control bacterial brood diseases. Anecdotal reports by beekeepers indicate that the antibiotic oxytetracycline (OTC) can be toxic when applied in powdered sugar to cells containing immature bee brood, but it was not known whether the purported toxicity is caused by the antibiotic or the sugar carrier. Additionally, the toxicity of various dusts, proposed for parasitic mite control, is poorly known. In the current studies, we tested OTC and two other antibiotics (tylosin and lincomycin, candidate compounds for use in honey bee colonies) in a powdered sugar carrier for larval toxicity. We also tested for larval toxicity, several dusts that have been proposed for mite control. OTC caused significant brood mortality of approximately 80% at the concentrations used in the hive (200 mg in 20 g sugar). In contrast, tylosin and lincomycin at the 200 mg dose were both similar to untreated controls, and only five times that concentration (1000 mg) caused significant brood mortality of approximately 65%. The addition of dusts, wheat flour, talc, and a commercially available protein supplement, BeePro, resulted in mortality levels between 65 and 80%, similar to that seen with OTC. The common antibiotic carrier, powered confectioners sugar, was nontoxic. The use of 100 unsealed brood cells was demonstrated to be a reliable means of assessing potential adverse affects of dry compounds on larval honey bees. Two new candidate antibiotics for use in honey bee colonies were less toxic to larval bees than the currently labeled antibiotic, OTC.

Animals↗

Molecular evolution of phosphoenolpyruvate carboxylase for C4 photosynthesis in maize: comparison of its cDNA sequence with a newly isolated cDNA encoding an isozyme involved in the anaplerotic function.

Molecular events associated with the evolution of an enzyme for C4 photosynthesis were investigated. In maize, at least three isozymes of phosphoenolpyruvate carboxylase [EC 4.1.1.31] are known: the C4-form, the C2-form and the root-form, being named according to their physiological roles and pattern of tissue distribution [Ting, I.P. & Osmond, C.B. (1973) Plant Physiol. 51, 448-453]. A cDNA clone which presumably encodes the C3-form isozyme was newly isolated and analyzed. Comparison of the sequences of the C3-form and C4-form isozymes revealed that (i) the homologies in the nucleotide and deduced amino acid sequences were 71 and 77%, respectively, and (ii) the gene for the C4-form isozyme evolved under strong G/C pressure. The genes for these isozymes were found to be located apart on different chromosomes. A phylogenetic tree was constructed using 8 amino acid sequences of phosphoenolpyruvate carboxylases from various sources. The topology of the tree indicated that, at least in monocots such as maize and sorghum, the genes for the C4-form and C3-form isozymes diverged from their common ancestral gene earlier than the monocot-dicot divergence (about 2 x 10(8) yr ago), though the divergence of maize (C4 plant) from wheat (C3 plant) is supposed to have occurred much later (6 x 10(7) yr ago).

Amino Acid Sequence↗

On the distribution and packing of RNA and protein ribosomes.

From the analysis of the measured radii of gyration of the RNA (Rg = 6.6 +/- 0.3 nm) and protein (Rg = 10.2 +/- 0.5 nm) components of the 50-S subparticle of Escherichia coli ribosomes it is concluded that proteins containing a large amount of hydrodynamically bound water are located on the periphery of the tightly packed RNA. We found that the common features of the measured X-ray scattering curves of the E. coli 70-S ribosome, its 30-S and 50-S subparticles and wheat 80-S ribosomes in the region of scattering angles corresponding to scattering vectors mu from 1 to 5 nm-1 reflect features of the RNA compact packing. A hypothesis is proposed that the compact packing of RNA helices in the range of Bragg distances of 4.5--2.0 nm is a general structural feature of all ribosomal particles.

Escherichia coli↗

[The problems of the child with food allergies].

In France, about 20% of schoolchildren are suffering from allergic diseases. Food allergy (FA) is steadily increasing for the last 20 years. Actually, 400,000 children are suffering from FA. Prevalence has increased this last decade. Frequency is estimated about 10% and increased twofold within 5 years. In France, the most common food allergens are: hen's egg (35%), peanut (24%), cow's milk (8%), mustard (6%), and fish (4%). Other food allergens as hazelnut, kiwi, wheat, sesame, seafood, and lupin. Cross reactivities to exist between fruits, vegetables pollen, latex and are more and more frequent. Multiple food allergies have recently been described.

Adolescent↗

Determination of the 13C/12C ratio of ethanol derived from fruit juices and maple syrup by isotope ratio mass spectrometry: collaborative study.

A collaborative study of the carbon-13 isotope ratio mass spectrometry (13C-IRMS) method based on fermentation ethanol for detecting some sugar additions in fruit juices and maple syrup is reported. This method is complementary to the site-specific natural isotope fractionation by nuclear magnetic resonance (SNIF-NMR) method for detecting added beet sugar in the same products (AOAC Official Methods 995.17 and 2000.19), and uses the same initial steps to recover pure ethanol. The fruit juices or maple syrups are completely fermented with yeast, and the alcohol is distilled with a quantitative yield (>96%). The carbon-13 deviation (delta13C) of ethanol is then determined by IRMS. This parameter becomes less negative when exogenous sugar derived from plants exhibiting a C4 metabolism (e.g., corn or cane) is added to a juice obtained from plants exhibiting a C3 metabolism (most common fruits except pineapple) or to maple syrup. Conversely, the delta13C of ethanol becomes more negative when exogenous sugar derived from C3 plants (e.g., beet, wheat, rice) is added to pineapple products. Twelve laboratories analyzed 2 materials (orange juice and pure cane sugar) in blind duplicate and 4 sugar-adulterated materials (orange juice, maple syrup, pineapple juice, and apple juice) as Youden pairs. The precision of that method for measuring delta13C was similar to that of other methods applied to wine ethanol or extracted sugars in juices. The within-laboratory (Sr) values ranged from 0.06 to 0.16%o (r = 0.17 to 0.46 percent per thousand), and the among-laboratories (SR) values ranged from 0.17 to 0.26 percent per thousand (R = 0.49 to 0.73 percent per thousand). The Study Directors recommend that the method be adopted as First Action by AOAC INTERNATIONAL.

Acer↗

Duck lymphocytes--III. Transformation responses to some common mitogens.

The lymphocyte transformation (LT) test was performed using duck blood lymphocytes stimulated with phytohaemagglutinin (PHA), concanavalin A (Con A), lentil lectin (LC), Roman snail lectin (HP), peanut agglutinin (PNA), Bandeiraea simplicifolia seed lectin (BSS), wheat germ agglutinin (WGA), horseshoe crab lectin (HSC), pokeweed mitogen (PWM) and E. coli lipopolysaccharide (LPS). Cells were cultured in microtitre trays, at 41.6 degrees C, 8 x 10(5) cells in 200 microliters medium (= 4 x 10(6) cells/ml) supplemented with 10% pooled duck serum. Mitogens were added at final concentrations of 0.1-100 micrograms/ml and triplicate cultures at each concentration were harvested daily for scintillation counting 6 hr after addition of 1 microCi [3H]thymidine. Three patterns of response were observed. The responses to Con A, LC, HP and HSC were greatest at high mitogen concentrations (40-100 micrograms/ml) throughout the 7 days of culture. With PHA, PNA, WGA and LPS maximum stimulation was obtained at 3-5 days, at which time the cells were responding to lower concentrations of mitogen than were required at other times during the experiment. The response to BSS and PWM showed increasing sensitivity to lower concentrations of mitogen during the first 3 days of culture and then stimulated most strongly at 2-10 micrograms/ml in cultures harvested after 4-7 days. Cells from two ducks were cultured for 3 and 5 days with selected concentrations of these mitogens; the results confirmed the variation in response to different mitogens. It is possible that these patterns of response are the outcome of stimulating different populations of duck lymphocytes.

Animals↗

Response of hexokinase enzymes and the insulin system to dietary carbohydrates in the common carp, Cyprinus carpio.

The response of the common carp to diets with varying amounts of digestible starch, provided either as pea meal (LP, HP, 30 and 46% peas, respectively) or as cereal (LW, HW, 30 and 46% wheat, respectively), was studied and compared with the response to a carbohydrate-free protein-rich diet (CF). Here we focused on the utilisation of dietary carbohydrates by examining the relationship between dietary starch intake, hepatic hexokinase activities, circulating insulin and muscle insulin receptor system. Plasma glucose concentration and hepatic high Km hexokinase (glucokinase, GK) activity were not affected by the content of digestible starch, but 6 h after feeding enzyme activity was higher in the fish fed carbohydrate diets. Similarly, low Km hexokinase (HK) activity was also higher in the fish 24 h after feeding. Fat gain and protein retention were significantly improved by increased digestible starch intake, especially in the HP group, which in turn, presented the highest plasma insulin levels. Glycogen stores were moderately increased by the ingestion of digestible starch. The number of insulin receptors was greater in the CF group than in fish on carbohydrates, except the HP group. Our results confirmed that the common carp uses dietary carbohydrates efficiently, especially when there are provided by peas. This efficiency might be related to the enhanced response of postprandial insulin observed in the HP group.

Animals↗

Estradiol regulates mRNAs encoding precursors to rat lutropin (LH) and follitropin (FSH) subunits.

Anterior pituitary mRNA was prepared using a microscaled method and translated in a wheat-germ cell-free system in the presence of [35S] labeled cysteine and methionine. Translation products, immunologically related to LH beta, FSH beta and the common subunit alpha, were isolated as precursors with antisera to denatured subunits and characterized by SDS-polyacrylamide gel electrophoresis and fluorography. The radioactive bands were excised from the gel and counted for quantitative evaluation. Our data show that translation of pituitary mRNAs from ovariectomized (ovx) rats results in precursor levels increased by 10 fold for alpha and 14 fold for LH beta as compared to the levels in normal rats. The increase in FSH beta precursor was impossible to evaluate as a specific immunoprecipitation product was undetectable in the case of normal rats. Estradiol, but not progesterone, administered in vivo to ovariectomized rats, reversed the stimulatory effect of ovariectomy on the expression of mRNAs coding for gonadotropin subunit precursors 48 h after injection. These results suggest that estradiol, but not progesterone, negatively regulates the synthesis of the pituitary gonadotropins in the female rats via changes in specific mRNA levels. This hormonal control probably occurs at the transcriptional level.

Animals↗

Food allergy. Manifestations, evaluation, and management.

Allergic reactions to food are more common among infants and children but occur in adults as well. Foods that are most often implicated in allergic reactions are eggs, cow's milk, nuts, wheat, soy products, whitefish, and crustacea. Gastrointestinal, respiratory tract, and dermatologic symptoms, as well as systemic anaphylaxis, may develop. In addition to history taking and physical examination, the workup may include skin testing, the radioallergosorbent test, and double-blind oral food challenge. Avoidance of offending antigens is the most important aspect of treatment. If exposure occurs, antihistamines and epinephrine may be needed for treatment of an acute reaction.

Adult↗

The role of cow milk allergy in increasing the severity of atopic dermatitis.

Previous studies have shown that up to 33% of children with atopic dermatitis have experienced food hypersensitivity and among different kinds of food allergens Cow Milk (CM) has almost always been one of the most common food allergens in children. The aim of this study is to evaluate the cow milk allergy (CMA) as an increasing factor of severity of atopic dermatitis. One hundred and nineteen children (between 1.5 months and 12 years of age) with atopic dermatitis in the sense of Hanifin and Rajka's criteria entered this study and the severity of atopic dermatitis was identified via the SCORAD index. In order to make the diagnosis of cow milk allergy, a careful history, and a familial history of allergy was taken and the results of skin prick test (SPT) with CM and 4 other food allergen extracts, Radioallergosorbent test (RAST) with CM allergens and a food challenge test with cow milk (fresh or dried) were used. Also a total serum IgE determination and an eosinophil count (with a stool exam) were accomplished. The clinical manifestations of atopic dermatitis in patients was started from their first day of life up to 10 years of age. The family history in 83% of the patients was positive. Positive skin prick test and RAST with CM allergens were positive in 37.9% and 29.3% of cases respectively and the response to challenge test with cow milk was positive in 35 out of 40 patients and in total 44.5% had CMA according to a positive history of cow milk allergy and a positive outcome of the IgE tests (SPT and/or RAST) or a positive challenge test with CM allergens. The results showed that the most common food allergens in patients with atopic dermatitis are certainly cow milk allergens (44.5%) whereas other food allergens are tomato (29.41%), egg (28.57%), nuts (9.24%) and wheat (3.36%) according to the skin prick test. The mean total serum IgE was 307.11 +/- 6.56 IU/ml (range = 6-5000) in children with CMA and 81.04 +/- 5.97 IU/ml (range = 1-5000) in children without CMA while the mean eosinophil count was 569.52 +/- 3.02 count/ml (range = 67-8500) and 314.22 +/- 2.94 count/ml (range = 5-5000) respectively. The mean severity of atopic dermatitis according to the SCORAD index was 60.76 in children with CMA and 44.29 in children without CMA. The severity of atopic dermatitis in patients with CMA was significantly higher than patients without CMA (p < 0.0001). Also the mean total serum IgE and mean eosionophil counts in children with CMA were significantly higher than in children without CMA (P < 0.01 and p < 0.0001, respectively). It shows the important role of CM allergen proteins in the induction and in increasing the severity of AD in children.

Allergens↗

Concentrations of choline-containing compounds and betaine in common foods.

Choline is important for normal membrane function, acetylcholine synthesis and methyl group metabolism; the choline requirement for humans is 550 mg/d for men (Adequate Intake). Betaine, a choline derivative, is important because of its role in the donation of methyl groups to homocysteine to form methionine. In tissues and foods, there are multiple choline compounds that contribute to total choline concentration (choline, glycerophosphocholine, phosphocholine, phosphatidylcholine and sphingomyelin). In this study, we collected representative food samples and analyzed the choline concentration of 145 common foods using liquid chromatography-mass spectrometry. Foods with the highest total choline concentration (mg/100 g) were: beef liver (418), chicken liver (290), eggs (251), wheat germ (152), bacon (125), dried soybeans (116) and pork (103). The foods with the highest betaine concentration (mg/100 g) were: wheat bran (1339), wheat germ (1241), spinach (645), pretzels (237), shrimp (218) and wheat bread (201). A number of epidemiologic studies have examined the relationship between dietary folic acid and cancer or heart disease. It may be helpful to also consider choline intake as a confounding factor because folate and choline methyl donation can be interchangeable.

Animals↗

The quantitation of IgG4 antibodies to three common food allergens by ELISA with monoclonal anti-IgG4.

Enzyme-linked immunosorbent assays, capable of detecting nanogram quantities of IgG4 to 3 common food allergens, have been developed with use of a monoclonal anti-human IgG4. Calibrated positive human sera were used to construct standard curves. The allergens employed, major protein constituents of egg (ovalbumin), milk (beta-lactoglobulin) and-wheat (gluten), were highly effective in coating microtitre plate wells; and the assays proved to be sensitive, reproducible and specific, in terms of both allergen and IgG subclass. On testing sera from a group of non-allergic individuals a high proportion were found to contain IgG4 antibodies to the 3 allergens. A pool of 60 sera obtained from blood donors also contained IgG4 antibodies to all 3 allergens. The results illustrate that IgG4 antibodies against common food constituents are frequently encountered in sera from normal individuals; and that this needs to be taken into consideration in assessing the possible role of such antibodies in immediate hypersensitivity reactions.

Allergens↗

The molecular genetic characterization of the 'Bobwhite' bread wheat family using AFLPs and the effect of the T1BL.1RS translocation.

Bobwhite is a generic name that refers to all sister lines derived from the cross CM 33203 with the pedigree Aurora//Kalyan/Bluebird/3/Woodpecker made by the CIMMYT bread wheat program in the early 1970s. Individual sister lines can be distinguished by their unique selection history. One of the parents, Aurora, contains the T1BL.1RS translocation from rye, and approximately 85% of the sister lines have inherited the translocation. The sister lines demonstrate great variability for agronomic traits such as maturity, height, grain color, reaction to leaf rust, stem rust, yellow rust, septoria leaf blotch and powdery mildew. Certain groups of sister lines derived from particular F(1) plants can be distinguished by their phenotype. One hundred and one Bobwhite sister lines were fingerprinted using four AFLP enzyme/primer combinations. Following multivariate analysis, two main and very distinct clusters were found, which reflected the presence or absence of the T1BL.1RS translocation. Within these clusters, lines clustered together, for the most part, with other sister lines sharing a common selection history. Removal of the AFLP markers that were correlated with the presence or absence of the translocation caused lines to cluster based on pedigree alone. Therefore, the presence of translocations in wheat could bias genetic diversity studies using unmapped markers such as AFLPs that are located on the translocated segment(s), with the result that the resulting clusters will not reflect the true degree of relatedness.

Journal Article↗

Relation between gliadin structure and coeliac toxicity.

Gliadin, the alcohol-soluble protein fraction of wheat, contains the factor toxic for coeliac patients. The numerous components of gliadin can be classified according to their primary structure into omega 5-, omega 1,2-, alpha- and gamma-type. Both omega-types have almost entirely repetitive amino acid sequences consisting of glutamine, proline and phenylalanine. alpha- and gamma-type gliadins contain four and five different domains, respectively, and are homologous within the domains III and V. Unique for each alpha- and gamma-type is domain I, which consists mostly of repetitive sequences rich in glutamine, proline and aromatic amino acids. Coeliac toxicity of gliadin is not destroyed by digestion with gastropancreatic enzymes. In vivo testing established the toxicity of alpha-type gliadins and in vitro testing of gliadin peptides revealed that domain I of alpha-type gliadins is involved in activating coeliac disease. The sequences -Pro-Ser-Gln-Gln- and -Gln-Gln-Gln-Pro- were demonstrated to be common for toxic gliadin peptides. Most of the in vivo and in vitro studies of synthetic peptides confirmed the importance of one or both of these sequences. Cultivated hexaploid, tetraploid and diploid wheat species do not differ significantly in potential toxic sequences of alpha-type gliadins.

Amino Acid Sequence↗