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PubMed2005

Analysis of the composition of an immunoglobulin E reactive high molecular weight protein complex of peanut extract containing Ara h 1 and Ara h 3/4.

Peanuts (Arachis hypogaea) contain some of the most potent food allergens. In recent years an increasing prevalence of peanut allergies both in children and adults has been observed in the USA and in Europe. In vitro identification and characterization of allergens including those from peanut have been frequently performed by Western blotting. However this method may alter the immunoglobulin E (IgE) antibody reactivity since the proteins are denatured by detergent treatment and/or reduction of disulfide bonds by reducing reagents and does not answer the question how peanut allergens interact with the human digestive apparatus and immune system. Size exclusion chromatography of peanut extract shows that approximately 90% of the total protein content is eluted as one peak in the exclusion volume with a molecular mass of over 200 kDa. The proteins of this fraction were analyzed by blue-native polyacrylamide gel electrophoresis (PAGE), immunoblotting, two-dimensional PAGE and Western blotting. A complex of Ara h 1 (Acc. no. P43237), Ara h 3/4 (AAM46958), Ara h 3 (AAC63045), Ara h 4 (AF086821), Gly 1 (AAG01363) and iso-Ara h 3 (AAT39430) was identified using patients' IgE and allergen-specific monoclonal antibodies; N-terminal sequencing and matrix-assisted laser desorption/ionisation-time of flight analysis verified these findings. A comparison of the peanut allergen sequences of Ara h 3/4, Ara h 3, Ara h 4 and peanut trypsin inhibitor (AF487543) and the proteins Gly 1 and iso-Ara h 3, not yet described as allergens, leads to the conclusion that these proteins are isoallergens of each other. It was shown that these isoallergens are post-translationally cleaved and held together by disulfide bonds in accordance to the 11S plant seed storage proteins signature.

Allergens↗
PubMed2002

Seed-specific, developmentally regulated genes of peanut.

Four cDNAs of seed-specific and developmentally regulated peanut ( Arachis hypogaeaL.) genes were identified by differential screening of a peanut-seed cDNA library using cDNA probes constructed from mRNAs isolated from immature and mature stages of the seed. Northern analysis, probed with the four cloned cDNAs, indicated that the genes represented by two cDNAs were expressed abundantly early in seed development, while another two were abundantly expressed later at the cell-expansion stages of seed development. These four genes did not show expression in roots, pegs or leaves. However, one of the early expressed genes was seed coat-specific. One of the clones, Psc11, had significant sequence similarity to subtilisin-like genes in Arabidopsis and soybean. Clones Psc32 and Psc33 had significant similarity to the peanut allergen genes Ara h II and Ara h 6, respectively. The sequence of clone Psc12 was unique and did not show significant similarity to any sequence in the databases. One of the four seed-specific clones showed restriction fragment length polymorphism (RFLP) among peanut lines representing the four peanut botanical varieties. These findings indicate that polymorphism exists in peanut seed-storage genes. This contrasts with other genes previously used for genetic mapping of cultivated peanut.

Journal Article↗
PubMed2005

Organization and evolution of resistance gene analogs in peanut.

The scarcity of genetic polymorphism in Arachis hypogaea (peanut), as in other monophyletic polyploid species, makes it especially vulnerable to nematode, bacterial, fungal, and viral pathogens. Although no disease resistance genes have been cloned from peanut itself, the conserved motifs in cloned resistance genes from other plant species provide a means to isolate and analyze similar genes from peanut. To survey the number, diversity, evolutionary history, and genomic organization of resistance gene-like sequences in peanut, we isolated 234 resistance gene analogs (RGAs) by using primers designed from conserved regions of different classes of resistance genes including NBS-LRR, and LRR-TM classes. Phylogenetic and sequence analyses were performed to explore evolutionary relationships both among peanut RGAs and with orthologous genes from other plant taxa. Fifty-six overgos designed from the RGA sequences on the basis of their phyletic association were applied to a peanut BAC library; 736 hybridizing BAC clones were fingerprinted and contigs were formed in order to gain insights into the genomic organization of these genes. All the fingerprinting gels were blotted and screened with the respective overgos in order to verify the authenticity of the hits from initial screens, and to explore the physical organization of these genes in terms of both copy number and distribution in the genome. As a result, we identified 250 putative resistance gene loci. A correlation was found between the phyletic positions of the sequences and their physical locations. The BACs isolated here will serve as a valuable resource for future applications, such as map-based cloning, and will help improve our understanding of the evolution and organization of these genes in the peanut genome.

Amino Acid Sequence↗
PubMedDate not supplied

Cholesterol vehicle in experimental atherosclerosis. Part 18. Comparison of North American, African and South American peanut oils.

Peanut oils were obtained from the United States (NAPNO), Africa (APNO), and South America (SAPNO) and their effects on atherosclerosis in rabbits fed 2% cholesterol were determined. The major differences among the oils were in the content of oleic (NAPNO, 48.9%; APNO, 58.6%; SAPNO, 36.4%) and linoleic (NAPNO, 29.6%; APNO, 21.7%; SAPNO, 41.1%) acids. In a series of 4 experiments it was found that South American peanut oil was 7% more atherogenic than African peanut oil and 18% more atherogenic than North American peanut oil. American peanut oil was 14% more atherogenic that corn oil (CO). South American peanut oil gave highest serum and liver lipid levels. The differences in atherogenicity may be due to the structure of the triglycerides of the various peanut oils.

Africa↗
PubMed1992

Allergenicity of peanut and soybean extracts altered by chemical or thermal denaturation in patients with atopic dermatitis and positive food challenges.

Peanuts and soybeans are two of the six most common foods to cause food hypersensitivity reactions in children. We used the serum of 10 patients with atopic dermatitis and positive double-blind, placebo-controlled, food challenges to peanut and two patients with atopic dermatitis and positive double-blind, placebo-controlled, food challenges to soybean to investigate the change in IgE-specific and IgG-specific binding to these proteins altered by either chemical or thermal denaturation. We used IgE- and IgG-specific ELISA-inhibition analyses to compare these effects on the crude peanut and crude soy extracts, as well as on the major allergenic fractions of both proteins. Heating the soy proteins at various temperatures and time intervals did not significantly change the IgE- or IgG-specific binding of the soy positive pooled serum. When the peanut proteins were subjected to similar heating experiments, the IgE- and IgG-specific binding did not change. When these same proteins were treated with enzymes in the immobilized digestive enzyme assay system used to mimic human digestion, the binding of IgE to the crude peanut and crude soy extracts was reduced; 100-fold for peanut and 10-fold for soybean. Therefore it appears that thermal denaturation of peanut and soybean protein extracts does not enhance or reduce IgE- and IgG-specific binding activity. Chemical denaturation appears to minimally reduce the binding of these proteins.

Adolescent↗
PubMed1994

The production of interferon-gamma in response to a major peanut allergy, Ara h II correlates with serum levels of IgE anti-Ara h II.

The current study was undertaken to examine the potential role of T cells in the pathogenesis of peanut allergy. Peripheral blood mononuclear cells (PBMCs) from patients with peanut allergy, patients with asthma, and nonatopic normal control subjects were assessed for proliferation after stimulation with a 17 kd major peanut allergen (Ara h II), ovalbumin, casein, soy, and Candida albicans. We found that Ara h II and C. albicans induced significantly higher levels of proliferation than ovalbumin, casein, and soy. Because interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) play critical roles in IgE regulation, we assessed the production of these cytokines after stimulation with C. albicans and Ara h II. C. albicans stimulated similar levels of IFN-gamma in all three study groups. In contrast, after stimulation with Ara h II, culture supernatants from PBMCs of subjects with peanut allergy contained significantly lower levels of IFN-gamma than did the PBMCs of the two control groups (p = 0.02). More important, there was a significant (p = 0.05) inverse correlation between the serum IgE anti-Ara h II levels and IFN-gamma production by PBMCs from the respective peanut-allergic patients. IL-4 protein was not detected in culture supernatants of PBMCs stimulated with Ara h II. However, amplification of cytokine gene transcripts by polymerase chain reaction did demonstrate IL-4 expression in Ara h II-stimulated PBMCs from both patients with peanut allergy and control subjects. These data suggest that the level of IFN-gamma production in response to Ara h II may be an important factor in determining the development of peanut-specific IgE responses.

2S Albumins, Plant↗
PubMed2000

Glycosylation of the cationic peanut peroxidase gene expressed in transgenic tobacco.

The major cationic peanut (Arachis hypogaea) peroxidase, secreted into the extracellular space, is a glycoprotein with three N-linked glycans (polysaccharides) which are connected to the peptide backbone at Asn-60, Asn-144 and Asn-185. In this report, a C-terminal histidine-tagged cationic peanut peroxidase gene was expressed in transgenic tobacco (Nicotiana tabacum). Tissue of the transgenic tobacco was cultured in suspension culture and the his-tagged peroxidase was purified in large quantities from 14-day-old suspension culture. The number of glycans, glycosylation sites and the chemical nature of glycan moieties attached to cationic peanut peroxidase expressed in transgenic tobacco were examined. Cationic peanut peroxidase isolated from the above transgenic tobacco had the identical number of complex glycans, attached at the same glycosylation sites as on cationic peanut peroxidase isolated from peanut suspension culture. Monosaccharide components of these glycans are N-acetylglucosamine (GlcNAc), mannose (Man), fucose (Fuc), xylose (Xyl) and galactose (Gal), the same sugars as found in native cationic peanut peroxidase.

Journal Article↗
PubMed2002

Effect of high-oleic trait and paste storage variables on sensory attribute stability of roasted peanuts.

There has been much interest in the effect of the high-oleic acid trait of peanuts on various quality factors since discovery of high levels of oleic acid in a peanut mutant genotype. The trait provides greater oxidative stability for the high-oleic oil and seed. Several research groups have investigated high-oleic peanut oil and roasted peanut flavor characteristics, which were similar within high-oleic lines compared to Florunner. It was observed that some high-oleic lines derived from the Sunrunner cultivar have consistently higher predicted breeding values for roasted peanut attribute than Sunrunner itself. This study investigated if this apparent effect of the trait was an artifact arising from the handling procedures during processing and storage or from flavor fade. High-oleic lines used were derived by backcrossing the trait into existing cultivars, and the comparison of sensory attribute intensity was with the recurrent parent used in backcrossing. Previous comparisons have been between lines differing in more than just oleate content, that is, with widely different background genotypes that could contribute to the differences observed. Differential rates of change in sensory attributes were found in different background genotypes, suggesting that the comparison of high- and normal-oleic lines should be made in common background genotypes as well as in common production and postharvest environments. There was no measurable change in roasted peanut attribute in samples stored at -20 degrees C over the 63 day duration of this experiment. There were changes in roasted peanut in samples stored at 22 degrees C, confirming that storage at -20 degrees C is sufficient for large studies that require multiple sensory panel sessions over a period of weeks.

Arachis↗
PubMed2002

Effect of the high-oleic trait on roasted peanut flavor in backcross-derived breeding lines.

The high-oleic trait of peanut (Arachis hypogaea L.) has been suggested to have a positive impact on the roasted peanut sensory attribute. A series of lines derived by backcrossing the high-oleic trait into several existing cultivars were compared with their parent cultivars at locations in Florida, Georgia, North Carolina, and Texas. Breeders grew their high-oleic lines and parents in three-replicate tests at one or two locations. The Florida high-oleic line F435-2-3-B-2-1-b4-B-B-3-b3-b3-1-B was grown at each location. The test included normal- and high-oleic variants of F435, GK 7, NC 7, NC 9, Sunrunner, Tamrun 96, and Tamspan 90. Sound-mature kernel samples were roasted, ground into paste, and evaluated by a sensory panel using a 14-point flavor intensity unit (fiu) scale. Background genotype had an effect (P < 0.01) on the heritable sensory attributes roasted peanut, sweet, and bitter. Oleate level had a positive effect on roasted peanut intensity, increasing it by 0.3 fiu averaged across all seven background genotypes. However, the magnitude of improvement varied across background genotypes. The high-oleic trait had no effect or increased the intensity of the roasted peanut attribute in each background genotype. The increase was greatest in Tamrun 96 (+0.6 fiu, P < 0.05) and Spanish genotypes Tamspan 90 (+0.4 fiu, P < 0.05) and F435 (+0.4 fiu, P < 0.10). A change of 0.5 fiu or more should be perceptible to consumers. Interaction between oleate level and background genotype was detected for sweet (P < 0.10) and bitter (P < 0.01) attributes. The trait had an increasing effect on the bitter attribute only in the background genotype of Tamspan 90 (+0.7 fiu, P < 0.01). There was a nonsignificant increase in bitterness in the other Spanish background genotype, F435. Changes in bitterness in runner- and Virginia-type backgrounds were close to zero. Incorporation of the high-oleic trait into peanut cultivars is likely to improve the intensity of the roasted peanut attribute, but it may also increase the bitter attribute in Spanish genotypes.

Arachis↗
PubMed2003

Comparative characterization of peanuts grown by aquatic floating cultivation and field cultivation for seed and resveratrol production.

Peanut pods (Tainan 12, a Spanish cultivar, Arachis hypogaea L.) have been obtained from peanuts grown in a newly developed aquatic floating cultivation system without artificial aeration or periodic renewal of the solution. The system provided a convenient status for examination of root and pod development. Compared to field-grown peanuts of the same cultivar, the aquatic-cultivated peanut pods and seeds were smaller, whereas seed/pod weight ratios, crude fat and protein contents, and SDS-PAGE protein patterns varied within similar ranges. During cultivation, the highest detected temperature of the aquatic solution was higher than the field-soil temperature. After gas chromatographic analysis of the fatty acid compositions, the oleic acid/linoleic acid ratio of the aquatic-cultivated seeds was higher than that of field-cultivated ones. When the peanut roots were collected, cleaned, dried, weighed, pulverized, and subjected to resveratrol analysis, dry root weights were 4.2 +/- 0.1 and 2.2 +/- 1.1 g/plant and resveratrol contents were 0.074 +/- 0.009 and 0.114 +/- 0.212 mg/g for the aquatic- and field-cultivated peanut roots, respectively. This indicates that the aquatic-cultivated peanut roots could be a potent and consistent source of resveratrol.

Agriculture↗
PubMed1998

HLA class II DRB1, DQB1 and DPB1 genotypic associations with peanut allergy: evidence from a family-based and case-control study.

BACKGROUND: Peanut is one of the most common foods provoking allergic reactions and is the most frequent cause of fatal and near-fatal food-induced anaphylaxis. However, as yet, little is known of the genetic and immunological mechanisms which underly peanut allergy. OBJECTIVE: Based on findings in other allergic diseases, we have investigated whether particular human leucocyte antigen (HLA) class II genetic polymorphisms contribute to the development of peanut allergy. METHODS: All individuals from 37 families each containing one or more peanut allergic individuals, plus nine unrelated patients (161 individuals in total, defined as the study group) were typed for the HLA class II DRB1, DQB1 and DPB1 loci, by PCR-based techniques. Genotype frequencies were compared with those found in 293 unrelated controls. RESULTS: Four class II genotypes (DRB1*08 (13.7% vs 4.8%; Pc = 0.026), DRB1*08/12 tyr 16 (22.4% vs 8.2%; Pc = 0.021), DQB1*04 (12.2% vs 2.7%; Pc = 0.0026) and DPB1*0301 (49.1 vs 22.5%; Pc = 0.00062)) were present at a significantly higher frequency in the study group compared with controls. Three of these genotypes (DRB1*08 (18.0%; Pc = 0.027), DRB1*08/12 tyr16 (24.0%; Pc = 0.029) and DQB1*04 (16.7%; Pc = 0.0029)) were also significantly increased in peanut allergic individuals compared with controls. In addition, two genotypes (DPB1*0101 and 0201) were significantly decreased in frequency in the overall study group, but not specifically in peanut allergic individuals. CONCLUSION: While other genetic factors may be important, results from this study indicate that HLA class II genetic polymorphism may play a role in determining susceptibility to peanut allergy.

Arachis↗
PubMedDate not supplied

A survey of aflatoxins in peanut butters, nuts and nut confectionery products by HPLC with fluorescence detection.

A preliminary survey in 1982 of aflatoxin levels in peanut butters indicated that 31 out of 32 samples of major national brand-named products examined contained less than 10 micrograms/kg aflatoxin B1 and that 59% of these were below the limit of detection (2 micrograms/kg). In contrast, of 25 peanut butters from specialist 'Health Food' outlets, 64% contained less than 10 micrograms/kg aflatoxin B1, the remainder ranging from 16 to 318 micrograms/kg, with one sample having a total aflatoxin concentration of 345 micrograms/kg. Subsequent surveys in 1983 and 1984 of 'Health Food' products confirmed that these manufacturers were still experiencing some difficulty in complying with the 30 micrograms/kg total aflatoxin voluntary guideline limit. A further survey in 1984 was carried out of 228 retail samples of nuts and nut confectionery products comprising peanuts (shelled, unshelled, roasted and salted), mixed nuts, almonds (both unblanched and ground), brazils (in shell), hazelnuts (in shell), chocolate-coated peanuts, peanut brittle and coconut ice. The results showed that 74% of the samples contained less than 0.5 microgram/kg of aflatoxin B1 with 3.1% exceeding the guideline tolerance of 30 micrograms/kg total aflatoxins, these being predominantly peanuts and brazils. The highest total levels of aflatoxins observed were in unshelled peanuts containing 4920 micrograms/kg and in a composite sample of visibly moulded brazils containing 17 926 micrograms/kg.

Aflatoxin B1↗
PubMed1980

Heart pathology in rats fed partially hydrogenated fish oil, rapeseed oil or peanut oil for 30 weeks.

132 male Sprague-Dawley rats were given diets for 30 weeks including rapeseed oil with 41.4% erucic acid, partially hydrogenated fish oil with 15.1% docosenoic acids, or peanut oil with no docosenoic acids. Four diets were isocaloric and contained respectively 21% rapeseed oil (8.7% w/w erucic acid), 10.5% rapeseed oil and 10.5% peanut oil (4.4% w/w erucic acid), 21% partially hydrogenated fish oil (3.2% w/w docosenoic acids) and 21% peanut oil. The fifth diet contained 4.3% peanut oil. The relative heart weights increased in rats fed rapeseed oil and partially hydrogenated fish oil, and abnormally enlarged hearts were found in 32% of the rats fed 21% rapeseed oil and in 5% of those fed 10.5% rapeseed oil. Heart lesions consisting of focal or confluent destruction of muscle cells were seen in all groups. The incidence was 96% and the average severity grade 2.5 when 21% rapeseed oil was given, and 61% and 1.3 respectively when 10.5% rapeseed oil was given. Minor heart lesions were found in 14% of the rats fed 21% partially hydrogenated fish oil, in 39% of those fed 21% peanut oil and in 12% when 4.3% peanut oil was given. It is concluded that partially hydrogenated fish oil is markedly less cardiopathogenic than high erucic rapeseed oil. The heart lesions that were found do not differ in incidence, severity or morphology from those found when peanut oil was given, or from those reported when other control fats and oils are given to rats for prolonged feeding periods.

Animal Feed↗
PubMed1999

Selective cloning of peanut allergens, including profilin and 2S albumins, by phage display technology.

BACKGROUND: Peanut kernels contain many allergens able to elicit IgE-mediated type 1 allergic reactions in sensitized individuals. Sera from sensitized patients recognize variable patterns of IgE-binding proteins. The identification of the IgE-binding proteins of peanut extract would faciliate improvement of diagnostic and immunotherapeutic approaches as well as development of sensitive test systems for the detection of hidden peanut allergens present as additives in various industrial food products and the investigation of their stability during processing of food products. METHODS: We applied the pJuFo cloning system based on the phage surface display of functional cDNA expression products to clone cDNAs encoding peanut allergens. Sera (n = 40) of peanut-allergic individuals were selected according to case history, radioallergosorbent test and immunoblot analysis to demonstrate IgE binding towards the newly identified recombinant allergens. RESULTS: In addition to the known allergens Ara h 1 and Ara h 2 we were able to identify four allergens with estimated molecular weights of 36, 16, 14.5 and 14 kDa. Three of them formally termed Ara h 4, Ara h6 and Ara h 7 show significant sequence similarities to the family of seed storage proteins and the fourth (Ara h 5) corresponds to the well-known plant allergen profilin. Immunoblotting of the six expressed recombinant allergens with 40 patients sera shows 14 individual recognition patterns and the following frequency of specific IgE binding: Ara h 1 was recognized by 65%, Ara h 2 by 85%, Ara h 4 by 53%, Ara h 5 by 13%, Ara h 6 by 38% and Ara h 7 by 43% of the selected sera. CONCLUSIONS: All of the selected peanut-positive sera can detect at least one of the six identified recombinant allergens which can be used to establish individual patients' reactivity profiles. A comparison of these profiles with the clinical data will possibly allow a further insight into the relationship between clinical severity of the symptoms and specific IgE levels towards the six peanut allergens.

2S Albumins, Plant↗
PubMed2004

Genetic diversity of peanut (Arachis hypogaea L.) and its wild relatives based on the analysis of hypervariable regions of the genome.

BACKGROUND: The genus Arachis is native to a region that includes Central Brazil and neighboring countries. Little is known about the genetic variability of the Brazilian cultivated peanut (Arachis hypogaea, genome AABB) germplasm collection at the DNA level. The understanding of the genetic diversity of cultivated and wild species of peanut (Arachis spp.) is essential to develop strategies of collection, conservation and use of the germplasm in variety development. The identity of the ancestor progenitor species of cultivated peanut has also been of great interest. Several species have been suggested as putative AA and BB genome donors to allotetraploid A. hypogaea. Microsatellite or SSR (Simple Sequence Repeat) markers are co-dominant, multiallelic, and highly polymorphic genetic markers, appropriate for genetic diversity studies. Microsatellite markers may also, to some extent, support phylogenetic inferences. Here we report the use of a set of microsatellite markers, including newly developed ones, for phylogenetic inferences and the analysis of genetic variation of accessions of A. hypogea and its wild relatives. RESULTS: A total of 67 new microsatellite markers (mainly TTG motif) were developed for Arachis. Only three of these markers, however, were polymorphic in cultivated peanut. These three new markers plus five other markers characterized previously were evaluated for number of alleles per locus and gene diversity using 60 accessions of A. hypogaea. Genetic relationships among these 60 accessions and a sample of 36 wild accessions representative of section Arachis were estimated using allelic variation observed in a selected set of 12 SSR markers. Results showed that the Brazilian peanut germplasm collection has considerable levels of genetic diversity detected by SSR markers. Similarity groups for A. hypogaea accessions were established, which is a useful criteria for selecting parental plants for crop improvement. Microsatellite marker transferability was up to 76% for species of the section Arachis, but only 45% for species from the other eight Arachis sections tested. A new marker (Ah-041) presented a 100% transferability and could be used to classify the peanut accessions in AA and non-AA genome carriers. CONCLUSION: The level of polymorphism observed among accessions of A. hypogaea analyzed with newly developed microsatellite markers was low, corroborating the accumulated data which show that cultivated peanut presents a relatively reduced variation at the DNA level. A selected panel of SSR markers allowed the classification of A. hypogaea accessions into two major groups. The identification of similarity groups will be useful for the selection of parental plants to be used in breeding programs. Marker transferability is relatively high between accessions of section Arachis. The possibility of using microsatellite markers developed for one species in genetic evaluation of other species greatly reduces the cost of the analysis, since the development of microsatellite markers is still expensive and time consuming. The SSR markers developed in this study could be very useful for genetic analysis of wild species of Arachis, including comparative genome mapping, population genetic structure and phylogenetic inferences among species.

Alleles↗
PubMed1997

Intake and nutritive value of florigraze rhizoma peanut silage for lactating dairy cows.

Florigraze rhizoma peanut (Arachis glabrata Benth.) is a very persistent, high quality legume that is well adapted to subtropical and tropical environments. This legume was ensiled and compared with corn silage (Zea mays) as a feedstuff for lactating dairy cows. Twelve Holstein cows, including 4 ruminally fistulated cows (mean, 70 days in milk), were used in an experiment with a 4 x 4 Latin square design replicated three times. Diets were formulated to contain 50% concentrate on a dry matter (DM) basis. Dietary treatments were rhizoma peanut silage and corn silage fed at DM ratios of 0:50, 20:30, 35:15, and 50:0. The dry matter intake, digestibilities of DM and crude protein, and production of milk and fat-corrected milk decreased quadratically as the percentage of legume in the diet increased. Nearly all of the decrease occurred when rhizoma peanut silage was the sole forage in the diet. The organic matter digestibility of the two forage types was similar; however, digestion of crude protein in rhizoma peanut silage was only 45% (calculated using simultaneous equations). Ruminal pH increased, and ammonia and total volatile fatty acid concentrations decreased, as the percentage of rhizoma peanut silage in the diet increased. In situ digestion rate constants for DM of rhizoma peanut silage were twice that of corn silage, but extent of DM digestion was greater for corn silage. Passage rates of concentrates and forage were unaffected by dietary treatments. Rhizoma peanut silage can replace 70% of corn silage in diets containing 50% concentrate without affecting dairy cow performance.

Ammonia↗
PubMedDate not supplied

Colonization of wounded peanut seeds by soil fungi: selectivity for species from Aspergillus section Flavi.

Soil is a source of primary inoculum for Aspergillus flavus and A. parasiticus, fungi that produce highly carcinogenic aflatoxins in peanuts. Aflatoxigenic fungi commonly invade peanut seeds during maturation, and the highest concentrations of aflatoxins are found in damaged seeds. A laboratory procedure was developed in which viable peanut seeds were wounded and inoculated with field soil containing natural populations of fungi, then incubated under different conditions of seed water activity and temperature. Densities of Aspergillus section Flavi in soil used for inoculating seeds were low relative to the total numbers of filamentous fungi (<1%). Aspergillus species from section Flavi present in soil included A. flavus morphotypes L and S strains, A. parasiticus, A. caelatus, A. tamarii and A. alliaceus. Wounding was required for high incidences of fungal colonization; viability of wounded seeds had little effect on colonization by Aspergillus species. Peanut seeds were colonized by section Flavi species as well as A. niger over broad ranges of water activity (0.82-0.98) and temperature (15-37 C), and the highest incidences of seed colonization occurred at water activities of 0.92-0.96 at 22-37 C. A. parasiticus colonized peanut seeds at lower temperatures than A. flavus, and cool soil temperatures relative to temperatures of aerial crop fruits might explain why A. parasiticus is found mostly in peanuts. Other fungi, dominated by the genera Penicillium, Fusarium and Clonostachys, colonized seeds primarily at water activities and temperatures suboptimal for section Flavi species and A. niger. Eupenicillium ochrosalmoneum frequently sporulated on the conidial heads of section Flavi species and showed specificity for these fungi. The inoculation of wounded viable peanut seeds with soil containing natural populations of fungi provides a model system for studying the infection process, the interactions among fungi and those factors important in aflatoxin formation.

Arachis↗
PubMed1998

Characteristics and composition of peanut oil prepared by an aqueous extraction method.

Peanut is one of the crops being tested for NASA's Advanced Life Support (ALS) program for future long-duration human space missions. The ALS program is developing an integrated system for biomass (food, oxygen) production and resource recycling. Oil will be used mainly for cooking and its availability is important for food preparation. Peanut seeds contain 40-50% oil and hence are considered an excellent source of oil. In the ALS environment, a simple, compact, and energy-efficient system is needed. The feasibility of such a method, peanut oil preparation by water extraction, was investigated. The results indicated the important processing conditions to be: a peanut particle size of 0.02 cm or less, a pH of 4, simmering for 20 min plus churning at 65 degrees C for a few hours, and a centrifugation at 6000 x gn to separate the oil. The oil recovery yield was about 80%. The saponification value, specific gravity, refractive index, and viscosity were similar to that of commercial peanut oil except the color was lighter for the water-extracted oil. Gas and thin-layer chromatographic analyses showed that fatty acid and lipid profiles were similar to the commercial peanut oil. The only difference observed was that the oil prepared by the aqueous method had lower linoleic and higher oleic acids than the commercial peanut oil. The oil prepared by this aqueous method appeared to be of high quality.

Arachis↗