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PubMed1990

Tolerance to long-term feeding of isolated peanut lectin in the rat: evidence for a trophic effect on the small intestines.

Previously we have shown that rats fed a diet containing raw peanut meal as the sole source of protein exhibited alterations in enzyme activity and composition of certain organs. To determine the effects of isolated peanut lectin on body growth and on the intestines, experiments were carried out in weanling, male, Sprague-Dawley rats fed a casein diet incorporated with purified peanut lectin at three levels, 0.004, 0.04, and 0.2% for 23 days. Body weight gain was normal with all three diets. In rats fed the 0.004 and 0.04% peanut lectin, there were no changes in any of the small intestinal mucosal parameters under study. However, in rats consuming the 0.2% peanut lectin diet, the proximal, mid, and distal third regions of the small intestines all showed marked increases in mucosal weight, protein, and DNA contents, but without altered villus morphology. Of the 3 brush border enzymes studied, namely maltase, gamma-glutamyltranspeptidase, and alkaline phosphatase, none was altered in activity in any region, suggesting that microvillus integrity was normal. These results are similar to the reported actions of red kidney bean lectin on the intestines. We conclude that peanut lectin at up to 0.2% of the diet does not inhibit food intake or growth of weanling rats and is apparently trophic for all areas of the small intestines.

Alkaline Phosphatase↗
PubMed1997

Identification and mutational analysis of the immunodominant IgE binding epitopes of the major peanut allergen Ara h 2.

A major peanut allergen, Ara h 2, is recognized by serum IgE from > 90% of patients with peanut hypersensitivity. Biochemical characterization of this allergen indicates that it is a glycoprotein of approximately 17.5 kDa. Using N-terminal amino acid sequence data from purified Ara h 2, oligonucleotide primers were synthesized and used to identify a clone (741 bp) from a peanut cDNA library. This clone was capable of encoding a 17.5-kDa protein with homology to the conglutin family of seed storage proteins. The major linear immunoglobulin E (IgE)-binding epitopes of this allergen were mapped using overlapping peptides synthesized on an activated cellulose membrane and pooled serum IgE from 15 peanut-sensitive patients. Ten IgE-binding epitopes were identified, distributed throughout the length of the Ara h 2 protein. Sixty-three percent of the amino acids represented in the epitopes were either polar uncharged or apolar residues. In an effort to determine which, if any, of the 10 epitopes were recognized by the majority of patients with peanut hypersensitivity, each set of 10 peptides was probed individually with serum IgE from 10 different patients. All of the patient sera tested recognized multiple epitopes. Three epitopes (aa27-36, aa57-66, and aa65-74) were recognized by all patients tested. In addition, these three peptides bound more IgE than all the other epitopes combined, indicating that they are the immunodominant epitopes of the Ara h 2 protein. Mutational analysis of the Ara h 2 epitopes indicate that single amino acid changes result in loss of IgE binding. Two epitopes in region aa57-74 contained the amino acid sequence DPYSP that appears to be necessary for IgE binding. These results may allow for the design of improved diagnostic and therapeutic approaches to peanut hypersensitivity.

2S Albumins, Plant↗
PubMed1995

Use of peanut and cowpea in wheat-based products containing composite flours.

Cowpeas and peanuts are legumes of major dietary and economic importance. They are favored worldwide because of their palatability, contribution to nutritional status, and low cost as a protein source compared to animal protein. Flours processed from cowpeas and peanuts have unique physico-chemical and sensory properties when used in composite flour mixtures. Appropriate blends of cowpea and peanut flours to replace wheat flour in Chinese-type noodles, muffins, and tortillas were determined using modelling and optimization procedures. For noodles, 15% peanut flour and 8% cowpea flour supplementation produced an acceptable product with high protein content (21%). For wheat flour replacement in muffins, up to 43% cowpea and up to 44% peanut flours may be used. However, when wheat flour replacement is 50% or greater, cassava flour should comprise 56 to 72% of the blend with a few exceptions. In tortillas, 24% cowpea and 46% peanut flours produced products similar in quality characteristics to those made from 100% wheat flour. The systematic approach used in these studies is more efficient than the traditional substitution method to optimize sensory qualities of wheat-based products containing composite flours.

Arachis↗
PubMed1993

[Food allergy: identifying and characterizing peanut allergens with patient sera and monoclonal antibodies].

The purpose of this study is to improve the diagnosis of peanut allergy. In order to standardize test substances for in vivo and in vitro diagnostic, the type I allergy-associated single components of peanuts have been identified and characterized with the aid of patients' sera and monoclonal antibodies. For allergen detection IEF-immunoprint-, SDS-PAGE-immunoblot- and 2-D electrophoresis-techniques have been used. A comparison of control sera and patients' sera showed that both contained peanut specific IgG-, IgA- and IgM-antibodies. In contrast, peanut-specific IgE-antibodies were only detectable with patients' sera. In IEF-immunoprint the most intensive IgE-bindings showed up in pl-range from pH 5.5 to 7.5. In SDS-PAGE-immunoblot major allergens could be identified at molecular weight ranges of 17, 30, 48 to 66 and 116 kD. Raising monoclonal antibodies against IgE-reactive components from peanut extract resulted in eight antibody-producing hybridoma cell lines, named PN-a to PN-h. ELISA-inhibition tests revealed common epitopes of monoclonal antibodies and patients' antibodies. Moreover, the monoclonal antibodies were tested to see whether they can be used for detection of hidden peanut allergens.

Allergens↗
PubMed2000

The high oleate trait in the cultivated peanut [Arachis hypogaea L]. II. Molecular basis and genetics of the trait.

A peanut variety with high oleate content has previously been described. When this high oleate variety was used in breeding crosses, the F2 segregation ratio of high oleate to normal oleate progeny was 3:1 or 15:1 depending on the normal oleate varieties used in the crosses. These data suggested that the high oleate trait is controlled by two recessive genes, and some peanut varieties differ from the high oleate variety by mutations in one gene, while others differ by mutations in two genes. The objective of this study was to understand the molecular nature of the high oleate trait and the various segregation patterns. In the previous paper in this issue, we reported that the level of transcripts expressed by one (ahFAD2B) of two homoeologous genes for oleoyl-PC desaturases in cultivated peanut is significantly reduced in high oleate varieties. In this report, we examined gene expression by RT-PCR/restriction digestion in a cross that shows a one-gene segregation pattern for the high oleate trait. Our data showed that the severely reduced level of ahFAD2B transcript correlates absolutely with the high oleate phenotype in this cross, suggesting that the single gene difference is correlated with the ahFAD2B transcript level. When we tested the enzyme activity of the proteins encoded by ahFAD2A and ahFAD2B by expression of the cloned sequences in yeast, only the ahFAD2B gene product showed significant oleoyl-PC desaturase activity. These data, combined with the observation that ahFAD2A shows a change (D150N) in a residue that is absolutely conserved among other desaturases, raised the possibility that the ahFAD2A in these normal and high oleate lines is a mutant allele. In support of this hypothesis, we found that another ahFAD2A allele in a normal oleate peanut line does not have the D150N change. This peanut line displays a two-gene-segregation pattern for the high oleate trait. In conclusion, our results suggest that a mutation in ahFAD2A and a significant reduction in levels of the ahFAD2B transcript together cause the high oleate phenotype in peanut varieties, and that one expressed gene encoding a functional enzyme appears to be sufficient for the normal oleate phenotype.

Alleles↗
PubMed2000

The high oleate trait in the cultivated peanut [Arachis hypogaea L.]. I. Isolation and characterization of two genes encoding microsomal oleoyl-PC desaturases.

Plant oils rich in oleate are considered superior products compared to oils rich in polyunsaturated fatty acids. Peanut (Arachis hypogaea L.) is one of the major oilseed crops, and high oleate mutant varieties with as much as 85% oleate have been reported. We examined the possibility that this mutant phenotype resulted from reduction in the activity or the transcript level of microsomal oleoyl-PC desaturase. Two independently generated high oleate mutants, M2-225 and 8-2122, and their partially isogenic lines with a normal oleate phenotype were used in this study. Two cDNA sequences coding for microsomal oleoyl-PC desaturases, ahFAD2A and ahFAD2B, have been isolated from the developing peanut seed with a normal oleate phenotype. Cultivated peanut is an allotetraploid, and sequence comparisons with the genes from the putative diploid progenitor species suggested that ahFAD2A and ahFAD2B are non-allelic, but homeologous genes originating from two different diploid species. Northern analysis showed that the transcripts of oleoyl-PC desaturases are highly abundant in both normal and high oleate peanut seeds in the second stage of development. Differential digestion of the RT-PCR products revealed a restriction site polymorphism between ahFAD2A and ahFAD2B, and allowed us to examine the level of transcript expressed from each gene. The results indicate that ahFAD2A is expressed in both normal and high oleate peanut seeds, but the steady state level of the ahFAD2B transcript is severely reduced in the high oleate peanut varieties. These data suggested that the reduction in ahFAD2B transcript level in the developing seeds is correlated with the high oleate trait.

Amino Acid Sequence↗
PubMed1984

Experimental atherosclerosis in rabbits fed cholesterol-free diets. Part 12. Comparison of peanut and olive oils.

The atherogenicity of peanut oil is well established as is the fact that the structure of the component triglycerides of peanut oil influences its atherogenicity. This study was carried out to determine if the relative saturation of peanut oil was partly responsible for the observed effects. Rabbits were fed a semipurified, cholesterol-free diet containing 14% of North American peanut oil (iodine value, 100), South American peanut oil (iodine value, 110) or olive oil (iodine value, 83) for 8 months. Rabbits fed olive oil exhibited higher levels of serum and liver lipids than did the two peanut oil-fed groups but significantly lower levels of aortic atherosclerosis. The findings confirm earlier observations that the structure of a fat can have an affect on its atherosclerogenic potential that is independent of its level of unsaturation.

Animals↗
PubMed1994

Epitope specificity and immunoaffinity purification of the major peanut allergen, Ara h I.

The antigenic and allergenic structure of Ara h I, a major allergen of peanuts, was investigated with the use of seven monoclonal antibodies obtained from BALB/c mice immunized with purified Ara h I. Previous work with monoclonal antibodies produced to allergens has primarily been done with inhalant allergens. Only recently have the major allergens of various foods been determined so that investigations with monoclonal antibodies into the allergenic epitopes could begin. When used as a solid phase in an ELISA, these monoclonal antibodies captured peanut antigen, which bound human IgE from patients with positive results to challenges to peanuts. The Ara h I monoclonal antibodies were found to be specific for peanut antigens when binding for other legumes was examined. In ELISA inhibition studies with the monoclonal antibodies, we identified four different antigenic sites on Ara h I. In related studies with pooled human IgE serum from patients with positive results to challenges to peanuts, we identified three similar IgE-binding epitopes. As a means of purifying the Ara h I allergen, we prepared an immunoaffinity column with monoclonal antibody 8D9. We eluted from this column the allergen Ara h I, which had a mean molecular weight of 63.5 kd and which bound human IgE from individual and pooled serum of patients with peanut sensitivity.

Allergens↗
PubMed1991

Inactivation of aflatoxin B1 in corn meal, copra meal and peanuts by chlorine gas treatment.

More than 75% degradation of aflatoxin B1 (AFB1) was achieved after treatment of AFB1-spiked corn meal, spiked copra meal (the residue of the kiln-dried coconut kernels after mechanical expulsion of oil) and peanuts artificially infected with Aspergillus parasiticus, with 11, 16 and 35 mg chlorine gas per g meal or peanuts, respectively. At these chlorine gas treatment levels, extension of the exposure period of the corn meal and copra meal beyond 2.5 hr, and the peanuts beyond 1 day, did not increase the percentage degradation of AFB1. The mutagenicity of chlorine-treated copra meal and peanuts spiked with AFB1 was greatly reduced compared with untreated controls, as determined in Salmonella typhimurium strain TA98 in the presence of rat liver S-9 mix; the reduction in mutagenicity was found to be highly correlated with the reduction in AFB1 levels. Reactions of chlorine with AFB1 or constituents of the meals or peanuts did not appear to generate new mutagenic compounds. The moisture content of the meals and peanuts appeared to be an important factor affecting the degradation of AFB1 by chlorine gas.

Aflatoxin B1↗
PubMed1995

Epitope specificity of the major peanut allergen, Ara h II.

The antigenic and allergenic structure of Ara h II, a major allergen of peanuts, was investigated with the use of four monoclonal antibodies obtained from BALB/c mice immunized with purified Ara h II. Our previous studies with monoclonal antibodies generated to peanut allergens showed this method to be useful for epitope mapping. When used as a solid phase in an ELISA, these monoclonal antibodies captured peanut antigen, which bound human IgE from patients with positive peanut challenge responses. The Ara h II monoclonal antibodies were found to be specific for peanut antigens when binding for other legumes was examined. In ELISA inhibition studies with the monoclonal antibodies, we identified two different antigenic sites on Ara h II. In similar studies with pooled human IgE serum from patients with positive challenge responses to peanuts, we identified two closely related IgE-binding epitopes. These characterized monoclonal antibodies to Ara h II will be useful for future studies to immunoaffinity purify the Ara h II allergen and to use in conjunction with recombinant technology for determining structure-function relationships.

2S Albumins, Plant↗
PubMed1998

Immunogenetic analysis of the heavy chain variable regions of IgE from patients allergic to peanuts.

Peanuts are one of the most allergenic of the foods, and hypersensitivity responses to peanut allergens can be fatal. Although the nature of the antigenic components of peanuts is being defined at the molecular level, there is little information on the induced IgE antibodies, which are central to the allergic reaction. Recognition sites of IgE antibody molecules arise from the variable regions of heavy and light chains (VH and VL). By using nested polymerase chain reactions with specific primers for the available repertoire of VH genes, together with primers in the constant epsilon region, we have amplified VH sequences of IgE from blood lymphocytes of two patients with peanut allergy. After cloning and sequencing the products, we found a predominance of VH1 family use in both patients, which was not found in control IgM-specific primers. The IgE VH sequences were highly somatically mutated, but in only six of 17 cases was there clear evidence for clustering of amino acids indicative of antigen selection. Previous results from patients with allergy to house dust mites have indicated predominance of VH5 use and little evidence for antigen selection. Although results from two patients allergic to peanuts must be regarded as preliminary, they do suggest that the IgE response to peanuts may have a different VH bias, with a similar mutational pattern.

Adolescent↗
PubMed1999

Prevalence of peanut and tree nut allergy in the US determined by a random digit dial telephone survey.

BACKGROUND: Allergy to peanuts and tree nuts (TNs) is one of the leading causes of fatal and near-fatal food-induced allergic reactions. These allergies can be lifelong and appear to be increasing in prevalence. Despite the seriousness of these allergies, the prevalence of peanut and TN allergy in the general population is unknown. OBJECTIVE: We sought to determine the prevalence of peanut and TN allergy among the general population of the United States. METHODS: We used a nationwide, cross-sectional, random digit dial telephone survey with a standardized questionnaire. RESULTS: A total of 4374 households contacted by telephone participated (participation rate, 67%), representing 12,032 individuals. Peanut or TN allergy was self-reported in 164 individuals (1.4%; 95% confidence interval [CI], 1.2%-1.6%) in 151 households (3.5%; 95% CI, 2.9%-4.0%). The prevalence of reported allergy in adults (1.6%) was higher than that found in children under 18 years of age (0.6%). In 131 individuals, details of the reactions were obtained. When applying criteria requiring reactions to be typical of IgE-mediated reactions (hives, angioedema, wheezing, throat tightness, vomiting, and diarrhea) within an hour of ingestion, 10% of these subjects were excluded. Among the remaining 118 subjects, allergic reactions involved 1 organ system (skin, respiratory, or gastrointestinal systems) in 50 subjects, 2 in 45 subjects, and all 3 in 23 subjects. Forty-five percent of these 118 respondents reported more than 5 lifetime reactions. Only 53% of these 118 subjects ever saw a physician for the allergic reaction, and only 7% had self-injectable epinephrine available at the time of the interview. The prevalence of peanut and TN allergy was adjusted by assuming that 10% of the remaining 33 subjects without a description of their reactions would also be excluded and correcting for a 7% false-positive rate for the survey instrument. A final "corrected" prevalence estimate of 1.1% (95% CI, 1.0%-1.4%) was obtained. CONCLUSIONS: Peanut and/or TN allergy affects approximately 1.1% of the general population, or about 3 million Americans, representing a significant health concern. Despite the severity of reactions, about half of the subjects never sought an evaluation by a physician, and only a few had epinephrine available for emergency use.

Adolescent↗
PubMed2001

Transformation of peanut (Arachis hypogaea L.) with tobacco chitinase gene: variable response of transformants to leaf spot disease.

Fertile transgenic plants of peanut (Arachis hypogaea L.) cv. TMV-2 expressing tobacco chitinase and neomycin phosphotransferase (npt II) genes were generated using an Agrobacterium tumefaciens (LBA4404/pBI121-pBTex)-mediated transformation system. A tissue culture-independent method wherein embryo in the mature seed is inoculated and reared into single plant transformant was used for transformation. Southern blot analysis of genomic DNA isolated from T(0) transformants and progeny plants (T(1)) demonstrated that the transgenes are stably integrated in the genome of transgenic peanut plants and inherited by the offspring. The expression of the heterologous chitinase gene driven by CaMV 35S promoter led to a high level of activity in some of the transgenic plants. Small-scale field tests indicated increased ability of these plants to resist the fungal pathogen Cercospora arachidicola (the causal organism of the leaf spot or Tikka disease of peanut), which is an important peanut pathogen. These results suggest that a heterologous chitinase gene was functional in peanut and expressed in healthy plants. The study also shows that peanut plants containing transgenically increased activity of chitinase were resistant to attack by the fungal pathogen C. arachidicola to different degrees. The strategy employed may be useful for the control of other fungal diseases of the crop.

Journal Article↗
PubMed2002

Peanut hull pellets as a single use sorbent for the capture of Cu(II) from wastewater.

This paper investigates the ability of peanut hulls and peanut hull pellets to adsorb copper from dilute aqueous metal ion solutions in batch and fixed bed systems. The kinetics of copper uptake onto the media have been investigated in batch systems and the influence of pH and particle size on the rate and extent of copper capture determined. The Langmuir and Freundlich isotherm theories were determined; the Langmuir model was found to best represent the equilibrium isotherm data. In normalized kinetic tests at least 75% of copper removal occurred within the first 20 min; 92% removal was effected within the first 50 min. The rate of uptake was optimum within the pH range 5-7.5, and media capacities remained relatively constant at a pH above 4.0. Bench-scale column studies were performed using peanut hull pellets. The overall capacity of pelletized peanut hulls was higher than for unmodified peanut hulls. Due to their demonstrated ability for Cu(II) uptake and favorable structural characteristics, pelletized peanut hulls could gain use as a low-cost, once-through biomass filter medium for copper-bearing waste streams.

Adsorption↗
PubMed2002

Clinical update on peanut allergy.

BACKGROUND: Peanut allergy is common, potentially severe, and there has been a recent surge in clinical investigation of this important food allergen. OBJECTIVE: To provide the reader with a clinically oriented update on peanut allergy. DATA SOURCES: English language articles were selected from PubMed searches (search terms: peanut allergy, food allergy, anaphylaxis) and selected abstracts with a bias toward recent (3 years) studies judged to have immediate, practical clinical implications. RESULTS: Peanut allergy is an increasing problem in western diets that include this food. Both genetic and environmental factors influences the expression of this allergy. The at-risk subject is an atopic individual, with heightened risk for those with atopic dermatitis and/or other food allergies. The allergy is long-lived for most, may increase slightly in severity over time, but approximately 20% of young children will develop tolerance. Parameters that may identify the subset likely to achieve tolerance have been identified. Several large studies have determined laboratory parameters (skin tests, peanut-specific serum immunoglobulin E concentrations) with excellent predictive value (>95%) to diagnose current clinical reactivity or tolerance, although oral food challenges are necessary for a definitive diagnosis. Numerous practical lessons concerning management (avoidance, treatment, and prevention) have been identified. CONCLUSIONS: Recent studies provide the clinician with an armament of improved diagnostic and treatment modalities for peanut allergy. Studies are underway that are likely to provide more definitive therapies in the near future.

Adolescent↗
PubMed2001

Vanillin content in boiled peanuts.

A high-performance liquid chromatographic (HPLC) method for determination of vanillin in boiled peanuts has been developed. Vanillin was extracted with acetonitrile by blending at high speed followed by purification of an aliquot of the extract on a minicolumn packed with Al(2)O(3). Vanillin was quantitated by HPLC on silica gel with n-hexane/2-propanol/water/acetic acid (2100/540/37/2, v/v) as a mobile phase. The recovery of vanillin added to fresh peanut hulls at 0.50 and 2.50 microg/g was 78.7 +/- 2.7 and 79.9 +/- 3.1%, respectively. The detection limit of vanillin in boiled peanuts was estimated at 0.05 microg/g. UV-detector response to vanillin was linear to at least 2.5 microg/injection. Free vanillin has been found in two commercial brands of boiled peanuts at low ppm levels. Both the kernels and the hulls contained vanillin, which was formed during hydrolysis of lignin, one of the major constituents of the peanut hulls. Since vanillin has a low flavor threshold, it could be considered as one of the major ingredients that determines the flavor of boiled peanuts.

Arachis↗
PubMed2005

Determination of the phytoalexin resveratrol (3,5,4'-trihydroxystilbene) in peanuts and pistachios by high-performance liquid chromatographic diode array (HPLC-DAD) and gas chromatography-mass spectrometry (GC-MS).

The phytoalexin resveratrol (3,5,4'-trihydroxystilbene) in edible peanut (Arachis hypogaea L.) and pistachio (Pistacia vera L.) varieties grown in Turkey was analyzed by high-performance liquid chromatographic diode array and gas chromatography-mass spectrometric detection. trans-Resveratrol in six peanut varieties, five pistachio varieties, and four market samples ranged between 0.03 and 1.92 microg/g. The Cerezlik 5025 peanut (1.92 +/- 0.01 microg/g) and Ohadi pistachio genotype (1.67 +/- 0.01 microg/g) had significantly higher trans-resveratrol contents. Peanuts contained 0.03-1.92 microg/g (av = 0.84 microg/g) of trans-resveratrol, whereas pistachio contained 0.09-1.67 microg/g (av = 1.15 microg/g). With exposure to UV light for 1 min, trans-resveratrol concentrations of samples ranged from 0.02 to 1.47 microg/g and those of cis-resveratrol from 0.008 to 0.32 microg/g. The occurrence of resveratrol in peanut and pistachio was confirmed by total ion chromatograms (TIC) of bis[trimethylsilyl]trifluoroacetamide derivatives of resveratrol isomers and comparison of the mass spectral fragmentation data with those of a resveratrol standard. Formation of the cis-isomer in pistachios was higher than in peanuts.

Arachis↗
PubMed2007

Comparison of extraction methods for the quantification of selected phytochemicals in peanuts (Arachis hypogaea).

Peanuts have been reported to contain bioactive phytochemicals, particularly isoflavones (genistein, daidzein, and biochanin A) and trans-resveratrol. Currently, limited data are available regarding the levels of these bioactive compounds in peanuts with variations in reported levels. The purpose of this study was to compare four methods of extraction [stirring, sonication, Soxtec, and microwave-assisted sonication (MAS)] for runner peanuts. Quantification of the selected compounds was conducted by reverse-phase high-performance liquid chromatography (RP-HPLC). The results showed that the MAS and Soxtec methods extracted significantly higher amounts of the phytochemicals. Also, the defatted peanuts gave significantly higher amounts of the phytochemicals compared to the nondefatted peanuts. The high levels of the isoflavones may be attributed to heat-induced conversion of conjugate glycosides to aglycons. The MAS and Soxtec methods may be used for total isoflavone content quantitation, while sonication or stirring may be the method of choice for quantitation of isoflavone composition (aglycons and glycoside conjugates) in peanuts.

Arachis↗