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PubMedDate not supplied

Fatal anaphylactic reactions induced by peanuts.

Peanuts are a common cause of food allergy, but they have infrequently been documented as causing fatal anaphylactic reactions. We review five previously reported fatalities caused by peanut allergy, along with data on IgE binding proteins in extracts of a commercial product containing peanuts that have been deflavored and reflavored and colored to resemble walnuts, pecans, or almonds. Ingestion of this product may pose hazards to peanut-sensitive persons. Finally, we identify several factors that may contribute to the severity and possible lethality of food-induced anaphylaxis.

Adolescent↗
PubMedDate not supplied

Peanut protein as a major cause of adverse food reactions in patients with atopic dermatitis.

Peanuts, along with milk and eggs, have been documented to account for approximately 80% of adverse reactions to foods in patients with atopic dermatitis. Over the past 3 years, we have evaluated 71 patients with atopic dermatitis, ranging from mild to severe in nature. These patients were initially evaluated by allergy prick skin testing and when appropriate had double-blind placebo-controlled food challenges done. Thirty-nine (55%) patients had a positive prick skin test to one of the foods tested. There were 80 food challenges performed with peanut, accounting for 12 (32%) of the 38 positive challenges in 23 (31%) patients. As in earlier studies, patients developed skin (97%), respiratory (55%), and gastrointestinal (32%) symptoms during the challenge. Of the five patients with histories of prior anaphylactic reactions four (80%) were to peanut. These studies indicate that children with all degrees of atopic dermatitis may benefit from evaluation for food hypersensitivity. They also show that peanut is a major food protein responsible for these reactions.

Adult↗
PubMed2000

Structure of the major peanut allergen Ara h 1 may protect IgE-binding epitopes from degradation.

In the past decade, there has been an increase in allergic reactions to peanut proteins, sometimes resulting in fatal anaphylaxis. The development of improved methods for diagnosis and treatment of peanut allergies requires a better understanding of the structure of the allergens. Ara h 1, a major peanut allergen belonging to the vicilin family of seed storage proteins, is recognized by serum IgE from >90% of peanut-allergic patients. In this communication, Ara h 1 was shown to form a highly stable homotrimer. Hydrophobic interactions were determined to be the main molecular force holding monomers together. A molecular model of the Ara h 1 trimer was constructed to view the stabilizing hydrophobic residues in the three dimensional structure. Hydrophobic amino acids that contribute to trimer formation are at the distal ends of the three dimensional structure where monomer-monomer contacts occur. Coincidentally, the majority of the IgE-binding epitopes are also located in this region, suggesting that they may be protected from digestion by the monomer-monomer contacts. On incubation of Ara h 1 with digestive enzymes, various protease-resistant fragments containing IgE-binding sites were identified. The highly stable nature of the Ara h 1 trimer, the presence of digestion resistant fragments, and the strategic location of the IgE-binding epitopes indicate that the quaternary structure of a protein may play a significant role in overall allergenicity.

Acids↗
PubMedDate not supplied

Laboratory proficiency testing of aflatoxins in corn and peanuts--a cooperative project between Thailand and the United States.

The objective of this project was to conduct an aflatoxin proficiency test program in government, academia, and industry laboratories in Thailand. Aflatoxin-free corn and peanuts and corn and peanuts naturally contaminated with aflatoxins diluted to approximately 25 micrograms/kg were analyzed. Homogeneity of prepared, naturally contaminated test samples was checked on multiple replicates. The test was conducted according to the ISO/IUPAC/AOAC INTERNATIONAL Harmonized Protocol with z scores indicating laboratory performance. The participants used 3 methods: enzyme-linked immunosorbent assay, thin-layer chromatography, and the minicolumn. Of 19 laboratories that reported results for aflatoxins in naturally contaminated corn, 13 (68%) performed satisfactorily, on the basis of the mean obtained by an expert laboratory, a calculated target value for standard deviation, and the z score. Of 21 laboratories that reported results for aflatoxins in naturally contaminated peanuts, 10 (48%) performed satisfactorily. For aflatoxin-free corn, 6 laboratories reported finding aflatoxins at > or = 10 ng/g, chiefly by the minicolumn method; for aflatoxin-free peanuts, 1 laboratory reported finding aflatoxins at > 10 ng/g. Subsequently, a workshop of lectures and laboratory sessions was conducted to improve performance. A new and simple successive outlier removal procedure applied to the same data removed the same laboratories as did the use of z scores.

Aflatoxins↗
PubMed1975

Peanut agglutinin, a new mitogen that binds to galactosyl sites exposed after neuraminidase treatment.

Peanut agglutinin, purified by affinity chromatography, agglutinates lymphocytes from mouse, rat, guinea pig, and man only after their treatment with neuraminidase. However, it stimulates only neuraminidase-treated rat and human cells. A similar number cell surface receptors for peanut agglutinin was found on neuraminidase-treated rat and mouse lymphocytes although the latter cells were not stimulated by the lectin. Galactose specifically inhibited the agglutination and stimulation of lymphocytes by peanut agglutinin. Sequential treatment of lymphocytes with neuraminidase and beta-galactosidase markedly reduced the response of the cells to stimulation by peanut agglutinin, soybean agglutinin, and galactose oxidase. It is suggested that the same galactosyl residue may be the target for the initial step in triggering lymphocytes by the above mentioned mitogens.

Agglutination Tests↗
PubMed1999

[Aflatoxins in food: tests of decontamination of peanut cakes by ionizing treatment].

The efficacy of ionising treatment for decontaminating peanut cakes was tested. The influence of cakes water content and the effect of ionisation dose rate were studied. The results obtained after a reverse phase liquid chromatographic determination of B1, B2, G1 and G2 aflatoxins have revealed an important contamination of the peanut cakes (up to 1000 ppb of total aflatoxin's contents). After ionising treatment at 25 kGy, the aflatoxins degradation in peanut cake's was less important in dried samples (about 5-10% at 0.55 water activity: aw) than in the humid ones (40-60% degradation at 0.95 water activity). At this dose, any indicative difference of the degradation rate of aflatoxins, with regard to the ionising process was observed. The efficacy of ionising treatment for decontaminating peanut cakes could probably be improved, however the economic interest of such process as alternative of the treatment with ammonia is questionable.

Aflatoxin B1↗
PubMedDate not supplied

Simultaneous quantitation of Aspergillus flavus/A. parasiticus and aflatoxins in peanuts.

A method was developed for simultaneous quantitation of Aspergillus flavus/A. parasiticus and aflatoxins in peanuts. Peanut samples were ground with an equal weight of water in a vertical cutter mixer to produce a slurry. Separate subsamples were taken for dilution-plating to determine total colony forming units (CFU)/g of A. flavus/A. parasiticus and for liquid chromatographic analysis to determine aflatoxin concentrations. Dry-grinding peanuts for homogenization of aflatoxins produced high temperatures that killed most of the A. flavus/A. parasiticus propagules. Addition of water to produce a slurry kept the temperature from rising above levels that killed the fungi. A 7 min grind time provided optimal homogenization for both the fungi and aflatoxins, so long as the temperature of the slurry did not exceed 45 degrees C. In the analysis of 60 shelled peanut samples, total aflatoxin concentrations ranged from 0 to 10,000 ng/g and total A. flavus/A. parasiticus ranged from 1.4 x 10(3) to 3.2 x 10(6) CFU/g. Regression analysis showed a significant positive correlation (p < 0.0001) between the quantities of A. flavus/A. parasiticus and aflatoxin (R2 = 0.82).

Aflatoxins↗
PubMed2002

[Genetic diversity and phylogeny of rhizobia isolated from peanut (Arachis hypogaea)].

Forty three rhizobium strains isolated from peanut (Arachis hypogaea) and 15 reference strains from other genus and species were analyzed by the method of 16S rRNA RFLP, 16S rRNA sequencing and 16S-23S IGS PCR RFLP. The results of the 16S rRNA RFLP shown that 43 strains tested were all ascribed to the genus of Bradyrhizobium phylogenetically. Strains tested were adjacent to the B. japonicum and far from B. elkanii 16S rRNA genotype. The genotypes generated by the 4 restriction endonucleases, Mbo I, Dde I, Hae III and Msp I, were same as the representatives of B. japonicum. The dendrogram generated by 16S rRNA sequence and Neighbor-joining method shown that peanut rhizobia clustered into the subcluster represented by B. japonicum and B. liaoningense, were more close to B. liaoningense genetically, and the sequence difference between them was less than 1%. High sequence similarity was also determined between B. liaoningense and B. japonicum. JZ1, representative strain of peanut rhizobia were systematically far from the B. elkanii, and the sequence divergence about 2%. The results from IGS RFLP analysis indicated that although they were phylogenetically close to B. japonicum and B. elkanii, peanut rhizobia forming an independent group at the similarity of 71% could be further divided into four subgroups, A, B, C and D. Subgroup A consisted of strains from different region, subgroup B was composed of strains from Wuchang, Qianjiang and Jingzhou, subgroup C was mainly composed of strains from Jingzhou and starins of subgroup D mainly from Neijiang. Reference strains from B. japonicum and B. elkanii were independently clustered into the subgroup E at the similarity of 71%. The geographical factor effect on genetic diversity of rhizobia was found.

Arachis↗
PubMedDate not supplied

Liquid chromatographic determination of aflatoxin levels in peanut butters using an immunoaffinity column cleanup method: international collaborative trial.

Thirteen laboratories in 7 different countries participated in a collaborative trial to evaluate the immunoaffinity column cleanup procedure with quantitation by fluorescence liquid chromatography (post-column derivatization) for the determination of aflatoxins in peanut butters. Participants were sent 10 randomly numbered samples of roasted peanut butter for analysis (5 pairs of undisclosed duplicates). Two of the pairs were "blank" peanut butters to which aflatoxin standards had been added; these "spiked" samples were used for recovery purposes. The other 3 pairs of samples were a nominal "blank" and 2 naturally contaminated peanut butters. A full statistical presentation of the results is given. Coefficients of variation (CVs) for the total aflatoxin determinations for mean levels of 4, 15, and 38 microns/kg were between 32 and 44% for the blank and 2 trial samples. Recovery levels for the 2 spiked samples were 51-67%, with aflatoxin B1 recovery of 60%. Relative standard deviations for method repeatability (RSDr) and reproductibility (RSDR) for the 3 trial samples were 15-26% and 33-45%, respectively.

Aflatoxins↗
PubMedDate not supplied

Visual and semiquantitative spectrophotometric ELISA screening method for aflatoxin B1 in corn and peanut products: follow-up collaborative study.

A joint AOAC/IUPAC (International Union of Pure and Applied Chemistry) interlaboratory study of an enzyme-linked immunosorbent screening assay (ELISA) for aflatoxins was conducted in laboratories in Canada, France, Japan, The Netherlands, Switzerland, Tunisia, and the United States. Twelve raw and roasted peanut and corn portions containing various concentrations of natural aflatoxins and supplemented when appropriate with aflatoxin B1 were distributed to participating laboratories for testing. The assay is based on competition between an enzyme-conjugated aflatoxin B1 and (free) aflatoxins in the test sample for aflatoxin-specific antibodies coated onto interior surfaces of microtiter wells. After a wash step to remove all unbound aflatoxins, a substrate added to each well is catalyzed from a colorless to a blue solution by any bound enzyme-conjugated aflatoxin B1 present. The intensity of the color decreases as the amount of free aflatoxin B1 in the test portion increases. Final determination of aflatoxin concentrations can be made by either visual comparison with standard solutions or spectrophotometric comparisons (at 650 nm) to knowns. Overall correlation was good between ELISA and thin-layer chromatographic results for corn and roasted peanut products, with 93 and 98% correct responses for visual and instrumental determinations, respectively. For instrumental determinations of aflatoxin in corn and roasted peanuts in the less than or equal to 20 ng/g range, the relative standard deviations for repeatability (RSDr) were 14.9 and 41.4%, respectively, and the relative standard deviations for reproducibility (RSDR) were 45.7 and 43.5%, respectively. For instrumental determination of greater than 20 ng/g, the respective RSDr and RSDR values were 19.4 and 52.7% for corn and 23.3 and 23.3% for roasted peanuts.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxin B1↗
PubMed1985

Jackfruit (Artocarpus integrifolia) and the Agaricus mushroom lectin fit also to the so-called peanut receptor.

The lectin from jackfruit (Artocarpus integrifolia) reacts with the peanut-specific lectin receptor represented by the T-disaccharide, which is also part of the Thomsen (= T)-Friedenreich antigen, namely O-beta-D-galactosyl-(1----3)-N-acetyl-D-galactosamine. The difference between the jackfruit lectin and peanut lectin has been shown to be mainly due to the further linkage of the T-disaccharide: Whereas the peanut lectin reacts with both anomeric forms, jackfruit lectin and the closely - with respect to its specificity - related Agaricus bisporus mushroom lectin react predominantly with the alpha-linked T-disaccharide, so that they cannot detect the lipid-linked T-disaccharide, as the peanut lectin does.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1981

Minicolumn detection methods for aflatoxin in raw peanuts: collaborative study.

The Holaday-Velasco method and a modified Holaday method have been compared. The former method combines the speed and simplicity of the Holaday extraction and cleanup with the sensitivity of the minicolumn originally described by Velasco. The combination method has been approved by the AOAC and the AACC for determining aflatoxin in corn. The Holaday method was modified by substituting toluene for benzene in the solvent partition, and methylene chloride for chloroform in the minicolumn development to eliminate use of hazardous solvents. The neutral alumina in the Holaday minicolumn was changed from activity V to activity III to provide a more stable column. At aflatoxin levels in raw peanuts of 13-20 ng/g, the presence of aflatoxin was missed by the modified Holaday method in 4 analyses (3 laboratories) of 42 reported. There were no misses in this contamination range by the Holaday-Velasco method. There were no misses by either method with samples containing greater than 20 ng total aflatoxins/g. Analysis of uncontaminated raw peanuts by the modified Holaday method resulted in 2 false positives of 14 reports; the Holaday-Velasco method produced no false positive reports from 15 analyses of uncontaminated peanuts. The Holaday-Velasco method was adopted official first action for peanuts.

Aflatoxins↗
PubMed1993

Study on digestibility and energy availability of pulses (peanuts and kidney beans) in men.

Four male Japanese students were fed a semisynthetic diet that included rice and whole eggs as protein sources for seven days (basal diet period), and in the following seven days (test diet periods), peanuts and then, kidney beans replaced part of the sugar in the basal diet. Urine and feces were collected throughout the periods and the contents of nitrogen, fat and energy in these excreta were determined. The results obtained were: 1) Digestibility of protein was 95.1 +/- 7.9% for peanuts and 84.8 +/- 3.7% for kidney beans. 2) Digestibility of fat was 83.5 +/- 8.5% for peanuts and 82.4 +/- 9.1% for kidney beans 3) The ratio of the total available energy to intake energy (Net Energy Availability) was 86.1 +/- 6.3% for peanuts and 84.8 +/- 3.1% for kidney beans.

Adult↗
PubMedDate not supplied

Performance of two immunochemical assays in the analysis of peanuts for aflatoxin at 37 field laboratories.

A study was conducted to measure the precision of 2 rapid aflatoxin assay systems in use at 37 peanut buying points during the 1991 harvest season. Aflatoxin laboratories were established at the 37 buying points to analyze peanut samples from all incoming farmers' stock loads as part of a joint project sponsored by various segments of the U.S. peanut industry and the U.S. Department of Agriculture. Eighteen laboratories were equipped with Neogen's veratox FSP rapid assay system, whereas 19 laboratories used Vicam's Aflatest rapid assay system. To monitor the performance of the field laboratories during the project, 3 portions of each of six 27 kg samples of ground peanuts were sent to each laboratory for analysis over a period of 6 weeks. Aflatoxin concentrations ranged from 0 to 300 ng/g when eight 200 g subsamples of each sample were analyzed by liquid chromatography (LC). For the 5 samples contaminated with aflatoxin, relative standard deviations for repeatability (RSDr) for laboratories using veratox FSP ranged from 18.66 to 53.29%, and the relative standard deviations for reproducibility (RSDR) ranged from 22.79 to 59.29%. For laboratories using the Aflatest system, RSDr values ranged from 18.70 to 41.48%, and RSDR values ranged from 23.84 to 47.56%. Horwitz ratios < 2.0 were found for 4 of the 5 contaminated samples for both methods, indicating that the overall precision of the 2 methods used in the project was good. Mean aflatoxin concentrations, as determined with the rapid assay systems, were generally lower than those determined by LC, particularly for more highly contaminated samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Aflatoxins↗
PubMed1993

Partial purification and characterization of a (glycosyl) inositol phospholipid-specific phospholipase C from peanut.

We have isolated a glycosyl inositol phospholipid (GIP) anchor-hydrolyzing activity from peanut seeds by a series of column chromatographic steps. The activity has a pH optimum below 6.0, requires calcium, and is inhibited by sulfhydryl reagents. It cleaves the GIP anchors of solubilized acetylcholinesterase from bovine erythrocytes and variant surface glycoprotein from Trypanosoma brucei. On the other hand, it does not act on membrane-bound GIP-anchored substrate or on inositol-acylated GIP anchor of human erythrocyte acetylcholinesterase. The only product released from [3H]myristate-labeled variant surface glycoprotein following treatment with the activity from peanut was 3H-labeled diacylglycerol. Together, these findings identify the activity from peanut seeds as a GIP anchor-hydrolyzing phospholipase C. The enzyme has been found to hydrolyze not only protein GIP anchors but also phosphatidylinositol, whereas it shows no activity against other phospholipids. The water-soluble products of phosphatidylinositol hydrolysis by peanut phospholipase C were characterized as a mixture of inositol 1,2-cyclic phosphate and inositol phosphate.

Acetylcholinesterase↗
PubMed2007

Does skin prick test reactivity to purified allergens correlate with clinical severity of peanut allergy?

BACKGROUND: Recognition of specific peanut allergens or the diversity of IgE binding to peanut allergens may play a role in the elicitation of severe allergic reactions. OBJECTIVE: To investigate whether sensitization to individual allergens Ara h 1, Ara h 2, Ara h 3 and Ara h 6 is correlated with clinical severity. METHODS: The reactivity of purified peanut allergens was measured by skin prick test (SPT) and by IgE immunoblot in 30 patients. The results were related to the clinical reactivity by history, and in 25 of them to the eliciting dose (ED). RESULTS: The majority of patients recognized Ara h 2 and Ara h 6. Patients with severe symptoms had a higher SPT response to Ara h 2 and Ara h 6 at low concentrations (0.1 micro g/mL) and to Ara h 1 and Ara h 3 at higher concentrations (100 micro g/mL), compared with patients with mild symptoms. They also recognized a greater number of allergens and showed a higher cumulative SPT response compared with patients with mild symptoms. No significant differences were observed between patients with a low or high ED. CONCLUSIONS: Ara h 2 and Ara h 6 appeared to be more potent than Ara h 1 and Ara h 3. Both SPT reactivity to low concentrations of Ara h 2 and Ara h 6 and to higher concentrations of Ara h 1 and Ara h 3 were shown to be indicative of severe symptoms.

2S Albumins, Plant↗
PubMed2025

Whole Genome Development of Specific Alien-Chromosome Oligo (SAO) Markers for Wild Peanut Chromosomes Based on Chorus2.

The cultivated peanut (Arachis hypogaea L.) is a globally important oilseed and economic crop, but its narrow genetic base limits breeding progress. Wild Arachis species represent valuable genetic resources for enhancing the resilience of the peanut cultigen. While wild species from section Arachis are widely used in breeding programs, the detection of alien chromosomes in hybrids remains challenging due to limited molecular tools. In this study, a cost-effective and efficient system was established for generating species-specific molecular markers using low-coverage next-generation sequencing data, bypassing the need for whole-genome assembly. Utilizing the Chorus2 software, specific alien-chromosome oligo (SAO) markers were developed for four wild species, A. duranensis (accession A19), A. pusilla (A10), A. appresipilla (A33), and A. glabrata (G2 and G3). A total of 1166 primer pairs were designed, resulting in 220 SAO markers specific to A. duranensis, 77 to A. pusilla, 112 to A. appresipilla, 69 to A. glabrata G2, and 59 to A. glabrata G3, with the highest development efficiency observed in A. duranensis (55.0%). These markers span all chromosomes of the five wild accessions. Genome-wide, chromosome-specific SAO markers enable the efficient detection of introgressed alien chromosomes and provide insight into syntenic relationships among homoeologous chromosomes. These markers offer an effective tool for identifying favorable genes and facilitating targeted introgression for the genetic improvement of the cultivated peanut.

Chorus2↗
PubMed2004

Development of an epitope-specific analytical tool for the major peanut allergen Ara h 2 using a high-density multiple-antigenic peptide strategy.

Using the major peanut allergen Ara h 2 as an example, an analytical tool enabling the determination of immunoglobulin E (IgE)-epitopes in processed food allergens was developed. We synthesized a multiple-antigenic peptide (MAP) of the IgE-reactive linear epitope 3 (amino acid positions 27-36) of Ara h 2 and raised a monospecific antiserum against this epitope to obtain a positive control for future epitope resolved diagnostics. First, a MAP of epitope 3, having a molecular mass of 7770 Da, was synthesized, purified, and its structure confirmed by liquid chromatography-mass spectrometry (electrospray ionization) (LC-MS(ESI)), matrix assisted laser desorption/ionization-time of flight (MALDI-TOF), and Edman sequencing. The MAP was then used to raise high titer antibodies in rabbits using the adjuvant Titermax and to characterize the specificity of IgE from allergenic patients sensitized to Ara h 2. The antiserum exclusively detects Ara h 2 in crude peanut extract with a titer of 10(7) by Western blot and reacts specifically with epitope 3 shown by epitope mapping for a library of solid-phase-bound synthetic 15-mer peptides covering the entire sequence of Ara h 2. Such IgE-reactive epitopes are of high analytical relevance as they could constitute the basis for epitope-specific detection systems for use in quality control in the food industry or for forensic purposes in cases of fatal reactions to otherwise undetected peanut proteins.

2S Albumins, Plant↗