Aflatoxin in Arizona cottonseed: Field inoculation of bolls byAspergillus flavus spores in wind-driven soil

Conditions typical of an Arizona monsoon were mimicked in the field to inoculate cotton plants withAspergillus flavus. Spores, mixed with autoclaved local soil, were blown onto cotton plants having bolls at all stages of maturity, using a modified commercial leaf blower. Half the plants were sprayed with water following inoculation. After one month, plants were pulled and the position of bolls mapped. All bolls were examined for bright-green-yellow fluorescence (BGYF) of lint, and ginned seeds from each boll were assayed for aflatoxin. Control non-wetted, non-inoculated bolls had no BGYF lint and no aflatoxin-containing seed. In contrast, 15% of the bolls from wetted, inoculated plants exhibited BGYF; 18% of these BGYF bolls had toxin. Only 3% of the non-wetted bolls had BGYF lint and none contained toxin. Lower bolls (fully fluffed at inoculation) were not infected, nor were upper bolls (flower stage at inoculation). Infection occurred only in bolls that had opened during the 30 days following inoculation. While the position of BGYF bolls on naturally contaminated plants was the same as for the inoculated, the ratio of toxic bolls to BGYF bolls was different. All BGYF bolls from plants naturally contaminated withA. flavus contained aflatoxin.     

Factors affecting aflatoxin contamination of cottonseed I. Contamination of cottonseed withAspergillus flavus at harvest and during storage

Examination of cottonseed production has shown that boll weevils (Anthonomus grandis), boll rots, and improper handling and storage conditions are critical factors inAspergillus flavus contamination of cotton-seed.A. flavus cultures were isolated from both field-collected and laboratory emerged boll weevils, as well as from boll weevil emergence holes. Diseased cotton bolls have been found to containA. flavus conidia. Infection byA. flavus was limited to the surface of cottonseeds collected from gin and from the gin blower. Seeds improperty stored outside the gin were infected internally withA. flavus. Observation of bright greenish-yellow fluorescence was not useful as a diagnostic procedure to detect contaminated seeds. Aflatoxin-producing potential ofA. flavus isolates is being investigated. WhenA. flavus conidia were artifically inoculated onto the surface of the seeds, 87% of the seeds from Athens, GA, were internally infected whereas only 29% of the seeds from Macon, GA, were internally infected.A. flavus invade the cottonseed embryo through the chalazal region, the micropylar region, or cracks developed in the seed coat during ginning. Invasion of cottonseed byA. flavus was predominant at 28, 30, and 37 C while at 15 and 20 C other fungi dominated in surface and internal invasions of cottonseed. At relative humidities of 75% and 80%,Chaetomium spp. successfully competed in growth on the surface, while at a relative humidity of 90% and above, fungi belonging to the orderMucorales outgrewA. flavus.     

Thermodynamics of solid formation in cottonseed oil

The aim of this study is to establish thermodynamic relations which govern the equilibrium of solid formation during the cooling of cottonseed oil either when tripalmitin is added to it or when the oil is cooled in the presence of solvent with consequent enrichment of the solid phase in certain triacylglycerols. We have established analytical expressions of the functions and variables of state that can describe the experimental results obtained. The effect of the addition of tripalmitin to refined cottonseed oil is well represented by simple expressions.     

Investigation of 1-decyne formation in cottonseed oil fried foods

1-Decyne identified in oxidized cottonseed oil was previously thought to originate from oleic acid. However, we have demonstrated that 1-decyne is a degradative product from the photo-oxidation of cyclopropenoid fatty acids (CPFA) naturally present in cottonseed oil. Products containing photooxidized cottonseed oil have the distinct off-flavor of 1-decyne. Experiments were conducted to identify the factors involved in 1-decyne formation. Reactions were done under the following conditions: (a) in the dark or under light, (b) with or without removal of CPFA from cotton-seed oil, (c) in the presence or absence of singlet oxygen quenchers, (d) in the presence or absencc of a hydroperoxide-reducing agent (triphenylphosphine), and (e) with or without photosensitizers. Methyl sterculate was used as a substrate for studying 1-decyne formation under photosensitized oxidation conditions in a model system. We have concluded that 1-decyne is formed by the photo-oxidation of CPFA utilizing chlorophyll as a photosensitizer. A reaction mechanism for 1-decyne formation is proposed. Presented at the 73rd AOCS annual meeting, Toronto, 1982.     

Dihydroxyacetone levels in electronic cigarettes: Wick temperature and toxin formation

Recently, we reported the presence of dihydroxyacetone (DHA), the active ingredient in sunless tanners, in the aerosol of an electronic cigarette. DHA has been shown to react with DNA in vitro. The FDA restricts the use of DHA to external application only. It states that it should not be inhaled, ingested, or come into contact with any areas containing mucous membranes, due to unknown risk. Herein, the quantification of DHA in the aerosols of three brands of e-cigarettes has been carried out. These included two devices with horizontal heating coil configurations as well as one with a sub-ohm resistance vertical heating coil. In order to understand and begin to address the origin of DHA and related aerosol products, the wicking properties of the three e-cigarettes were compared. DHA levels were analyzed by a combination of GS/MS and ¹H NMR. DHA was found in all three e-cigarettes, with substantially less in the sub-ohm, vertical coil device as compared to the horizontal coil devices (e.g., 0.088 µg/puff vs. 2.29 µg/puff, respectively). Correspondingly, the temperature of the wet layer of the wick for the vertical coil was relatively stable, compared to the wicks for the horizontal coils, upon increasing battery power output. This result is in agreement with prior studies of e-cigarette wicking efficiency and aerosol toxin formation. The temperature measurements reported are a simple means for comparing devices with different design properties during operation.

Copyright © 2018 American Association for Aerosol Research     

Diffusivities of hydrogen and glyceryl trioleate in cottonseed oil at elevated temperature

The diffusivities of hydrogen and glyceryl trioleate in cottonseed oil were determined at different iodine values. The diffusivity of hydrogen was shown to be ca. 100 times as great as that of the glyceryl trioleate. The diffusivities were shown to be dependent upon the iodine values. This influence could be explained, at least in the case of the glyceryl trioleate diffusion, by the difference of the viscosity of the oil. A separate determination of the solubility of hydrogen in the oil was a necessary part of the diffusivity determination.     

The AFLATOX® Project: Approaching the Development of New Generation,Natural-Based Compounds for the Containment of the Mycotoxigenic Phytopathogen Aspergillus flavus and Aflatoxin Contamination

The control of the fungal contamination on crops is considered a priority by the sanitary authorities of an increasing number of countries, and this is also due to the fact that the geographic areas interested in mycotoxin outbreaks are widening. Among the different pre- and post-harvest strategies that may be applied to prevent fungal and/or aflatoxin contamination, fungicides still play a prominent role; however, despite of countless efforts, to date the problem of food and feed contamination remains unsolved, since the essential factors that affect aflatoxins production are various and hardly to handle as a whole. In this scenario, the exploitation of bioactive natural sources to obtain new agents presenting novel mechanisms of action may represent a successful strategy to minimize, at the same time, aflatoxin contamination and the use of toxic pesticides. The Aflatox^® Project was aimed at the development of new-generation inhibitors of aflatoxigenic Aspergillus spp. proliferation and toxin production, through the modification of naturally occurring molecules: a panel of 177 compounds, belonging to the thiosemicarbazones class, have been synthesized and screened for their antifungal and anti-aflatoxigenic potential. The most effective compounds, selected as the best candidates as aflatoxin containment agents, were also evaluated in terms of cytotoxicity, genotoxicity and epi-genotoxicity to exclude potential harmful effect on the human health, the plants on which fungi grow and the whole ecosystem.     

Inactivation of aflatoxins in cottonseed meal by ammoniation: I. Reaction studies

Cottonseed meal containing an average of 340 ppb total aflatoxins was treated with anhydrous liquid ammonia under varying conditions of time, temperature, and ammonia concentration. Meal moisture was held constant at 10%. A unique sampling device was constructed and used to withdraw meal at time intervals as frequent as 5 min during the reaction period, without interrupting the ammoniation process. The rate of aflatoxin inactivation occurring under a given set of treatment conditions was thus monitored. The data obtained in this study indicate that the inactivation of aflatoxins in cottonseed meal, as determined by chemical assay, may be successfully achieved by use of less stringent conditions of time, temperature, pressure, and moisture content than previous studies have indicated.     

Solubilities of cottonseed oil and the phase distribution of fatty acids in methyl alcohol at elevated temperature and pressure

A study was made to determine whether methyl alcohol could be used for the selective extraction of fatty acids from crude cottonseed oil under high temperature and high pressure conditions. Equilibrium data and phase relationships were obtained at several temperatures, and corresponding triangular phase diagrams were prepared. From these, it was concluded that the proposed process would not be commercially attractive inasmuch as excessive amounts of solvent would be needed. The research described in this article was conducted in cooperation with the Cotton Research Committee of Texas.     

Effect of storage conditions on increase in aflatoxins in cottonseed: A small lot study

Small lots of cottonseed with low aflatoxin contamination were stored at 15, 18 and 22% moisture at 80 and 85 F. Maximum aflatoxin content was reached within 30 days’ storage. The range in moisture content was sufficient to cause a 10-fold increase in aflatoxin content between seed stored at 15.1 and 21.8% moisture. Aeration caused about a five-fold mean increase in aflatoxin content. Presented at the AOCS Meeting, Houston, May 1971.     

Lack of regioselectivity in formation of oxohydroxyoctadecenoic acids from the 9- or 13-hydroperoxide of linoleic acid

Either 9-hydroperoxy-trans-10,cis-12-octadecadienoic acid or 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid was treated with the catalyst, cysteine-FeCl₃, in the presence of oxygen. Oxohydroxyoctadecenoic acids were among the many products formed as a result of hydroperoxide decomposition. A mixture of 9(13)-oxo-13(9)-hydroxy-trans-11(10)-octadecenoic acids (δ-ketols) was produced from either isomeric hydroperoxide. The formation of isomeric δ-ketols from 9-hydroxy-trans-12,13-epoxy-trans-10-octadecenoic acid (epoxyol), a known product of 13-hydroperoxy-cis-9,trans-11-octadecadienoic acid decomposition, implies that the epoxyol is an intermediate. The mechanism was elucidated by the facile conversion of the epoxyol (methyl ester_ to methyl 9(13)-oxo-13(9)-hydroxy-trans-11(10)-octadecenoates with a Lewis acid, BF₃-etherate. Presented at the 14th World Congress, International Society for Fat Research, Brighton, U.K., September 17–22, 1978. The mention of firm names or trade products does not imply that they are endorsed or recomended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Magnetoelectrolysis in the presence of bubble formation at the cathode

The effect of a uniform magnetic field on mass transfer at a cathode with competing metal deposition and H₂ bubble formation in electrolysis was studied in the case of a laboratory-scale nickel electrowinning cell. The enhancement factor reaches a minimum at a specific magnetohydrodynamic body force density and is, in general, less than in the case of a single, metal-depositing cathode reaction.     

Coalescence during bubble formation at two neighbouring pores: An experimental study in microscopic scale

This work studies the effect of the liquid properties and the operating conditions on the interactions between under-formation bubbles in a cell equipped with two adjacent micro-tubes (i.d. ) for the gas injection, placed 210, 700 and apart. This set-up simulates, though in a simplified manner, the operation of the porous sparger in a bubble column, and it is used to study the bubble interactions observed on the sparger surface. Various liquids covering a wide range of surface tension and viscosity values are employed, while the gas phase is atmospheric air. A fast video recording technique is used both for the visual observations of the phenomena occurring onto the tubes and for the bubble size measurements. The experiments reveal that the interactions between under-formation bubbles as well as the coalescence time depend strongly on the liquid properties, the distance between the tubes and the gas flow rate. Two correlations, which can be found helpful for the bubble column design, have also been formulated and are in good agreement with the available experimental data.     

Peramine alkaloid variation in Neotyphodium-infected Arizona fescue: effects of endophyte and host genotype and environment

We determined concentrations of peramine, the only alkaloid produced by Neotyphodium-infected (E+) Arizona fescue plants (of the four major types typically assayed in infected grasses), in a long-term field experiment. Four plant genotypes with (E+) and without (experimentally removed, E–) their respective haplotypes (two haplotypes in two plant genotypes) of Neotyphodium were grown in the field under manipulated soil moisture and nutrients. Peramine production required the presence of the endophyte; plants without their endophytes did not contain peramine. Whereas the endophyte was necessary for peramine production, levels of peramine did not vary by Neotyphodium haplotype within plant genotypes. Furthermore, peramine levels did not differ among soil moisture and nutrient treatments, and growth and reproductive measures of the host grass explained little of variation in peramine levels. Instead, peramine levels differed significantly between plant genotypes harboring the same endophyte haplotype, suggesting that plant genotype, rather than endophyte haplotype or environment, largely determines levels of peramine in Arizona fescue. The results suggest that whereas the endophyte is required for peramine production, the plant genotypic background in which the endophyte is embedded, rather than endophyte haplotype or environmental factors, mostly influences peramine levels within this population of Arizona fescue.     

Phase formation of Mn-doped zinc silicate in water at high-temperatures and high-pressures

Phase formation of Mn-doped zinc silicate (Zn₂SiO₄:Mn²⁺, ZSM) in high-temperature and high-pressure water was studied by in situ observations with a hydrothermal diamond anvil cell (HDAC). Precursor was prepared with zinc oxalate dihydrate, manganese oxalate, and silica, where the Zn/Mn/Si molar ratio was 192/8/120 to 199/1/120. Conditions of particle formation were at temperatures up to 650 °C and at pressures up to 1250 MPa. Precursors dissolved at temperatures of 145–203 °C and needle-like particles formed through homogeneous nucleation at temperatures from 357 to 374 °C, close to the critical point of water. The needle-like particles grew at growth rates of 0.5–3.8 μm/s and were identified to be ZSM as evident from their green luminescence. ZSM synthesized in supercritical water (400 °C for 180 min) by batch reactions had comparable luminescence with that of ZSM produced by solid-state reaction (1200 °C for 240 min) using the same precursor. The key finding in this work is that the precursors can be made to dissolve in near-critical water and that this allows ZSM to form via a homogeneous nucleation process.