Balancing selection for aflatoxin in Aspergillus flavus is maintained through interference competition with, and fungivory by insects.

The role of microbial secondary metabolites in the ecology of the organisms that produce them remains poorly understood. Variation in aflatoxin production by Aspergillus flavus is maintained by balancing selection, but the ecological function and impact on fungal fitness of this compound are unknown. We hypothesize that balancing selection for aflatoxin production in A. flavus is driven by interaction with insects. To test this, we competed naturally occurring aflatoxigenic and non-aflatoxigenic fungal isolates against Drosophila larvae on medium containing 0-1750 ppb aflatoxin, using quantitative PCR to quantify A. flavus DNA as a proxy for fungal fitness. The addition of aflatoxin across this range resulted in a 26-fold increase in fungal fitness. With no added toxin, aflatoxigenic isolates caused higher mortality of Drosophila larvae and had slightly higher fitness than non-aflatoxigenic isolates. Additionally, aflatoxin production increased an average of 1.5-fold in the presence of a single larva and nearly threefold when the fungus was mechanically damaged. We argue that the role of aflatoxin in protection from fungivory is inextricably linked to its role in interference competition. Our results, to our knowledge, provide the first clear evidence of a fitness advantage conferred to A. flavus by aflatoxin when interacting with insects.

Urinary aflatoxin M1 in Port-au-Prince and a rural community in north-east Haiti.

Aflatoxins (AFs) are hepatocarcinogenic mycotoxins that can contaminate grains and oil seeds in tropical and sub-tropical areas and have been detected in maize and peanut products of Haiti. The first objective was to assess human exposure to AFs among Haitians at an urban hospital (GHESKIO) and a rural health centre (HCBH). The second objective was to test the association between AF exposure and reported dietary intake of potentially contaminated foods, such as maize, peanut products and milk. Measurement of urinary AFM1 by HPLC revealed that among 367 participants 14% and 22% at GHESKIO and HCBH, respectively, had detectable AFM1. The maximum and median AFM1 concentrations for all detected samples were 700 pg AFM1 ml(-1) and 11.7 pg ml(-1), respectively. Detection of AFM1 was significantly associated with peanut consumption (p < 0.05). Controlling for diet and age group in a logit model, patients who reported peanut consumption the day of the survey and patients from HCBH had greater log odds of excreting detectable AFM1 (p < 0.001 and 0.002, respectively); females had lower log odds (p = 0.020). Recalled frequency of consuming non-dairy animal-sourced foods, an indicator of diet quality, approached significance (p = 0.056) as an inverse predictor of urinary AFM1 detection. The findings augur the need for interventions that will improve food safety in Haiti and limit exposure to AFs, particularly among rural communities.

A comparative study of the human urinary mycotoxin excretion patterns in Bangladesh, Germany, and Haiti using a rapid and sensitive LC-MS/MS approach.

An improved "dilute and shoot" LC-MS/MS multibiomarker approach was used to monitor urinary excretion of 23 mycotoxins and their metabolites in human populations from Asia (Bangladesh), Europe (Germany), and the Caribbean region (Haiti). Deoxynivalenol (DON), deoxynivalenol-3-glucuronide (DON-3-GlcA), T-2-toxin (T-2), HT-2-toxin (HT-2), HT-2-toxin-4-glucuronide (HT-2-4-GlcA), fumonisin B1 (FB1), aflatoxins (AFB1, AFB2, AFG1, AFG2, AFM1), zearalenone (ZEA), zearalanone (ZAN), their urinary metabolites α-zearalanol (α-ZEL) and ß-zearalanol (ß-ZEL), and corresponding 14-O-glucuronic acid conjugates (ZEA-14-GlcA, ZAN-14-GlcA, ß-ZEL, α/ß-ZEL-14-GlcA), ochratoxin A (OTA), and ochratoxin alpha (OTα) as well as enniatin B (EnB) and dihydrocitrinone (DH-CIT) were among these compounds. Eight urinary mycotoxin biomarkers were detected (AFM1, DH-CIT, DON, DON-GLcA, EnB, FB1, OTA, and α-ZEL). DON and DON-GlcA were exclusively detected in urines from Germany and Haiti whereas urinary OTA and DH-CIT concentrations were significantly higher in Bangladeshi samples. AFM1 was present in samples from Bangladesh and Haiti only. Exposure was estimated by the calculation of probable daily intakes (PDI), and estimates suggested occasional instances of toxin intakes that exceed established tolerable daily intakes (TDI). The detection of individual mycotoxin exposure by biomarker-based approaches is a meaningful addition to the classical monitoring of the mycotoxin content of the food supply.

Phenolics, sugars, antimicrobial and free-radical-scavenging activities of Melicoccus bijugatus Jacq. fruits from the Dominican Republic and Florida.

Edible fruits of the native South American tree Melicoccus bijugatus Jacq. are consumed fresh or in traditional food, drink and medicinal preparations. Some therapeutic effects of these fruits may be due to phenolics and sugars. Aqueous acetone, methanol or ethanol tissue extracts of different cultivars or collections of M. bijugatus fruits from the Dominican Republic and Florida were analyzed for total phenolics and free radical scavenging activity by UV-vis spectroscopy, sugars by gas chromatography, and antimicrobial activity by the disc diffusion assay. Total phenolics and free radical scavenging activities ranked: seed coat > embryo > pulp extracts. Montgomery cultivar fruits had the highest total phenolics. For sugars: pulp > embryo and highest in Punta Cana fruit pulp. In all extracts: sucrose > glucose and fructose. Glucose:fructose ratios were 1:1 (pulp) and 0.2:1 (embryo). Pulp extracts had dose-response antibacterial activity and pulp and embryo extracts had antifungal activity against one yeast species. Phenolics and sugars were confirmed with thin-layer chromatography and nuclear magnetic resonance. Sugar-free pulp fractions containing phenolics had slightly more antimicrobial activity than H2O-soluble pulp fractions with sugars. Results indicate M. bijugatus fruits contain phenolics, sugars and other H2O-soluble compounds consistent with therapeutic uses.

Characterization of phenolics by LC-UV/vis, LC-MS/MS and sugars by GC in Melicoccus bijugatus Jacq. 'Montgomery' fruits.

Fruits of the native South American tree Melicoccus bijugatus Jacq. (Sapindaceae) are consumed for both dietary and medicinal purposes, but limited information is available about the phytochemistry and health value of M. bijugatus fruits. Fruit tissues of the Florida Montgomery cultivar were assessed for sugars, using gas chromatography, and for total phenolics, using UV spectroscopy. Reverse phase high performance liquid chromatography (HPLC) fingerprints of crude methanolic pulp, embryo and seed coat extracts were obtained at 280 nm. Phenolics were characterised by both HPLC UV/vis analysis and HPLC electrospray ionization tandem mass spectrometry. Major sugars detected in the pulp and embryo extracts were sucrose, followed by glucose and fructose. The glucose:fructose ratio was 1:1 in the pulp and 0.1:1 in the embryo. Total phenolic concentrations of the fruit tissues were in the order: seed coat > embryo > pulp. Phenolic acids were identified mostly in pulp tissues. Phenolic acids, flavonoids, procyanidins and catechins were identified in embryo tissues, and higher molecular weight procyanidins were identified in seed coat tissues. This study provides new information about the phytochemistry and the potential health value of the Montgomery cultivar M. bijugatus fruit tissues.

Constraints on the delivery of animal-source foods to infants and young children: case studies from five countries.

UNLABELLED: BACKGROUND. Optimal feeding of infants and young children in developing countries includes daily feeding of animal-source foods. OBJECTIVE. To evaluate constraints on the availability of animal-source foods at the community level, access to animal-source foods at the household level, and intake of animal-source foods at the individual level among children under 3 years of age in case studies in five developing countries: Mexico, Peru, Haiti, Senegal, and Ethiopia. METHODS: Data were obtained from published and unpublished research and from program experiences of health and agriculture specialists. RESULTS: In Ethiopia, 27% to 51% of case-study children had consumed an animal-source food on the previous day; from 56% to 87% of children in the other case-study sites had consumed an animal-source food on the previous day. Data on intake of animal-source foods in grams were only available for the Latin American case-study sites, where daily milk intake was high in Mexico and Peru (195 and 180 g/day, respectively) and the intakes of meat, fish, and poultry (MFP) (29.0 and 13.6 g/day) and of egg (18.4 and 4.9 g/day) were low. The conceptual model guiding this work identified more constraining factors at the community and household levels than at the individual level. The most common constraints on feeding animal-source foods to young children were poverty, animal health, and land degradation at the community level; cost of animal-source foods and limited livestock holdings at the household level; and caregivers' perceptions of giving animal-source foods to children at the individual level. CONCLUSIONS: For program planning, it is useful to simultaneously consider factors that affect community availability of household access to, and children's intake of animal-source foods. Efforts to overcome individual-level constraints on intake of animal-source foods should be coupled with activities to address community and household constraints.

Canavanine-induced longevity in mice may require diets with greater than 15.7% protein.

BACKGROUND: Dietary administration of 1% canavanine had been shown to improve survival in female BALB/c mice consuming diets containing 23.4% protein (dry matter basis). METHODS: In order to determine if this effect also obtains at more moderate dietary protein concentrations, 30 female BALB/c mice were fed a basal diet with 14% protein (15.7% dry matter basis) and another 30 were fed the same diet plus 1% canavanine. RESULTS: Neither mean (Control 873.2 d, Canavanine 870.0 d; SEM = 34.2 d; P = 0.949 from ANOVA) nor median (Control 902 d, Canavanine 884.5 d; P = 0.9058 from Mann-Whitney) lifespans differed between groups.Although mean antinuclear antibody (ANA) titers did not differ between control and canavanine-treated mice at 833 days of age (19.84 vs 20.39 respectively; SEM = 2.64; P = 0.889 from ANOVA), one canavanine-treated mouse displayed an outlying ANA value of 50 (next lower value = 30) denoting possible early sign of incipient autoimmune disease in that individual. CONCLUSION: There may be an interaction between dietary protein level and canavanine with respect to lifespan in mice.

Solutions exist for constraints to household production and retention of animal food products.

This article reviews constraints to household level animal source food production in developing countries and suggests solutions to some of these constraints. These constraints include land, labor, money, feed quality, water, disease, animal genetics, roles for animals beyond food production, grazing techniques and an understanding of the entire agricultural system at the household level. Better understanding of farming systems and the elements that comprise it which affect animal food production permits wise management of nutrient flows and enhanced sustainability.

Isolation, identification, and characterization of compounds from acer rubrum capable of oxidizing equine erythrocytes.

OBJECTIVE: To identify compounds in Acer rubrum that cause hemolysis or oxidation of equine erythrocytes and determine whether these toxins are found in other Acer spp. SAMPLE POPULATION: Equine erythrocytes. PROCEDURE: Washed erythrocytes were incubated with extracts and fractions of Acer spp that were separated by thin layer chromatography. Methemoglobin and hemolysis were measured spectrophotometrically. Compounds within Acer spp fractions associated with cell oxidation or hemolysis were identified by gas chromatography-mass spectrometry. RESULTS: Erythrocytes incubated separately with either A. rubrum, A. saccharum, or A. saccharinum extracts had increased methemoglobin formation, compared with extract-free control samples. Two Acer spp fractions had toxic effects on erythrocytes in vitro. A major component of the Acer fraction that caused a significant amount of methemoglobin formation was identified as gallic acid. An amount of gallic acid equivalent to that found in A. rubrum extract significantly increased methemoglobin, compared with extract-free control erythrocytes, but caused less methemoglobin formation than A. rubrum extracts did. A potential co-oxidant, 2,3-dihydro-3,5-dihydroxy-6-methoxy-4H-pyran-4-one, was found in the A. rubrum extract and may have been responsible for increasing methemoglobin formation. A second A. rubrum fraction caused methemoglobin formation and significant hemolysis. A. saccharum and A. saccharinum extracts caused hemolysis but less than the A. rubrum extracts did. CONCLUSION AND CLINICAL RELEVANCE: Oxidants in A. rubrum are also found in A. saccharum and A. saccharinum, and the ingestion of A. saccharum and A. saccharinum poses a potential threat to horses.

Essential fatty acid profiles differ across diets and browse of black rhinoceros.

In captivity, black rhinoceros (Diceros bicornis) suffer from idiopathic skin lesions that may be linked to dietary deficiencies, in particular essential fatty acid deficiency (EFAD). Therefore, a study was undertaken from July 1995 to May 1997 to characterize the diet of captive D. bicornis in North American zoos and measure fat and fatty acid composition in zoo diet, and African and North American browses. Descriptions of all dietary items offered to black rhinos on a daily basis were compiled from 20 North American zoos; zoo diet contained (mean +/- SE) 61 +/- 2% hay, 28 +/- 2% grain pellets, 6 +/- 1% produce, and 5 +/- 1% fresh browse, with hay and grain pellets together comprising nearly 90% of items offered. Gas chromatography-mass spectrometry analysis (GC-MS) was used to measure triacylglycerol equivalent (TAG), total fatty acids (TFA), and essential fatty acids (EFA) in zoo diet, and African and North American browses. North American browse contained more TAG and TFA than did zoo diet or African browse. Zoo diet contained more linoleic acid (18:2n6) and less linolenic acid (18:3n3) than either African browse corrected for degradation losses or North American browse, whether measured as weight percentage of dry sample or as weight percentage of TFA. In addition, the ratio of 18:2n6 to 18:3n3 was significantly lower in both browses than in zoo diet. There are significant nutritional differences between the major dietary components of North American captive black rhinoceros diets and native African browses that warrant further exploration given the health problems associated with this animal in captivity.