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C W Hesseltine

Publications and source records attributed to C W Hesseltine.

At least 19 recordsLinked to original sources
PubMed1987

Aspergillus nomius, a new aflatoxin-producing species related to Aspergillus flavus and Aspergillus tamarii.

Aspergillus nomius is described and represents a new aflatoxigenic species phenotypically similar to A. flavus. Strains examined were isolated from insects and agricultural commodities. Separation from A. flavus is based on the presence of indeterminate sclerotia and a lower growth temperature. Comparisons of DNA relatedness show A. nomius to have only relatively recently evolved from A. flavus and A. tamarii.

Aflatoxins↗
PubMed1983

Five-year study of mycotoxins in Virginia wheat and dent corn.

Every year during the 5-year period 1976-1980, approximately 100 samples each of corn and wheat from trucks delivering the grains at elevators in Virginia were collected by personnel of the Federal Grain Inspection Service and shipped to NRRC. Samples were analyzed as soon as possible for aflatoxin, zearalenone, and ochratoxin A. The 3 mycotoxins were not detected in any wheat sample. Zearalenone and ochratoxin A were not found in any corn sample; however, aflatoxin was detected in at least 25% of the corn samples from every crop year. In 1976-1980, the incidence of aflatoxin at levels of 20 ng/g or more (the Food and Drug Administration guideline) ranged from 18 to 61%; aflatoxin incidence above 100 ng/g was 5-29%. The average aflatoxin levels in corn samples collected in the 5 years varied from 21 to 137 ng/g. Moisture content of the samples was not determined, so aflatoxin levels given may be higher than they were at harvest. However, there are obviously differences from year to year. In freshly harvested corn samples collected by fieldmen of the Statistical Reporting Service in yield surveys in 1978 and 1979, aflatoxin incidence above the FDA guideline was 10 and 13%, and above 100 ng/g was 4 and 7%. The average aflatoxin level in all samples collected in 1978 was 13 ng/g and in 1979, 36 ng/g. Some aflatoxin can be expected yearly in Virginia corn, but the incidence and levels vary from year to year.

Food Contamination↗
PubMed1983

Treatment of freshly harvested 1980 Georgia dent corn samples collected for aflatoxin analysis.

In 1980, corn was harvested from six 15-ft rows in each of 67 fields in Georgia for aflatoxin analysis. Every sixth ear from each field was placed in a sample bag to be dried the day of collection. The rest of the corn was husked and shipped to Peoria in cardboard boxes. When undried ear samples arrived in Peoria, each sample was randomly separated into 5 equivalent subsamples. One set of 67 subsamples was shelled and dried as soon as possible to avoid further aflatoxin formation. Two other sets of 67 subsamples were stored 3 and 6 weeks before shelling and drying. The remaining 2 sets of ear samples were placed in plastic bags with 5% Monoprop (1 part propionic acid plus 1 part versite) and stored 3 and 6 weeks before shelling and drying. The samples dried in Georgia before shipping had an average total aflatoxin level of 217 ng/g. Samples shelled and dried immediately after arrival had an average level of 202 ng/g. Samples shelled and dried after 3 and 6 weeks of storage had average total aflatoxin levels of 417 and 387 ng/g, respectively. Samples stored 3 and 6 weeks in the presence of 5% Monoprop (2.5% propionic acid) had average total aflatoxin levels of 120 and 157 ng/g, respectively.

Aflatoxins↗
PubMed1978

Wild rice as fermentation substrate for mycotoxin production.

Many cereal grains have been studied for their suitability as substrates for the fermentative production of mycotoxins. However, except for aflatoxin, wild rice has not been investigated. Hence, five mold cultures known to produce the mycotoxins ochratoxin-A, penicillic acid, patulin, vomitoxin, and zearalenone were grown on wild rice under varying conditions of moisture and temperature to determine whether this grain would serve as a suitable substrate for toxin production. Under appropriate fermentation conditions, good yields of ochratoxin-A and moderate amounts of patulin were obtained, but only small amounts of penicillic acid, vomitoxin, and zearalenone were elaborated. An extract from a sample of naturally molded wild rice contained 0.8 microgram of patulin per g of rice. The predominating mold was identified as Aspergillus clavatus. Under identical cultural conditions, this isolate and a known patulin-producing strain of A. clavatus yielded approximately equivalent amounts of the mycotoxin.

Aspergillus↗
PubMed1978

Evaluation of Sclerotinia sclerotiorum as a potential mycotoxin producer on soybeans.

Solvent extracts of Sclerotinia sclerotiorum sclerotia were nontoxic to mice and chicken embryos; psoralens were not detected. Solvent extracts of soybeans inoculated with 10 strains of S. sclerotiorum were toxic on injection but nontoxic on per os administration to mice. The presence of chlorinated hydrocarbons in the soybeans may partially help explain toxicity by intraperitineal injection.

Animals↗
PubMed1977

Swelling of Penicillium digitatum conidia by a Fusarium acuminatum NRRL 6227 metabolite.

Fusarium acuminatum NRRL 6227 produces an antifungal metabolite that causes incubating conidia of several Penicillium species to swell 5-10 diameters while inhibiting germination. The swollen conidia are spherical, translucent, nonviable and easily shattered with a slight physical pressure; however, they remain resistant to osmotic shock. This antibiotic has been identified as a cyclic peptide composed of alanine, glutamic acid, leucine, threonine and tyrosine.

Antifungal Agents↗
PubMed1977

Survey of 1975 wheat and soybeans for aflatoxin, zearalenone, and ochratoxin.

Wheat samples (102 lots) were collected from Virginia, North Carolina, southeastern Missouri, southern Illinois, and Kentucky. Soybean samples (180 lots) were collected from Virginia, Illinois, Iowa, Minnesota, Nebraska, Alabama, Arkansas, and Texas. Samples of both commodities were analyzed for zearalenone, aflatoxin, and ochratoxin by the Eppley method. None of the 3 mycotoxins was detected in soybeans. Aflatoxins and ochratoxin A were not detected in wheat, but zearalenone was detected in 19 of 42 samples collected in Virginia. Half of the Virginia samples were collected because they were mold-damaged. Zearalenone levels ranged from 0.36 to 11.05 ppm; the identity of the zearalenone was confirmed by gas-liquid chromatography and mass spectroscopy. Gibberella zea infection (6-60%) was detected in all of the zearalenone-positive samples; 6-60% of the kernels in the samples tested contained G. zea.

Aflatoxins↗
PubMed1976

Fungus-fermented soybeans benefit the life cycle of Japanese quail (Coturnix coturnix japonica).

Feeding quail chicks diets containing soybeans fermented with two cultures of Aspergilli (A. oryzae N.R.R.L. 451 and A. oryzae N.R.R.L. 506) resulted in significantly superior weight gains (p less than 0.05) through a 4-week growth period and confirmed previous observations made with identical cultures in broiler studies. Subsequent hen-day egg production and egg size were changed little by diets containing fermented soybeans. The numerical increases in fertility and hatchability were not significant. Progeny also responded to the fermented soybean diets, some carry-over effects were evident.

Animal Feed↗
PubMed1976

Survey of U.S. wheat for ochratoxin and aflatoxin.

A total of 291 hard red winter wheat samples, 286 hard red spring wheat samples, and 271 soft red winter wheat samples were analyzed for the presecne of ochratoxin and aflatoxin. Samples in all grades came from those collected during crop years 1970-1973 for grade determinations by the Agricultural Marketing Service, U.S. Department of Agriculture. Sensitivity limits of the analytical method as carried out were 1-3 ppb aflatoxin B1 and 15-30 ppb ochratoxin A. No aflatoxin was detected in any sample. Three samples of hard red winter wheat (Grades U.S. No. 4 and 5 and Sample Grade) contained ochratoxin A (trace, 35, and 25 ppb, respectively). Eight of the hard red spring wheats contained ochratoxin A (15-115 PPB); these were in Grades U.S. No. 4 and 5 and Sample Grade.

Aflatoxins↗
PubMed1975

Free fatty acids identified as antitryptic factor in soybeans fermented by Rhizopus oligosporus.

The trypsin-inhibitory activity observed in cooked soybeans fermented by Rhizopus oligosporus (fungus used in tempeh fermentation) has been examined. The active compounds have now been isolated by ethanol extraction and thin-layer chromatography and have been identified as free fatty acids by infrared spectroscopy and gas-liquid chromatography. Oleic, lineoleic, and linolenic acids are primarily responsible for the increased trypsin-inhibiting activity of cooked soybeans after fermentation. The free fatty acids are liberated from oil in the soybeans by fungal lipase, and they differ from other reported soybean trypsin inhibitors that are protein in nature. Free fatty acids have been previously reported to inhibit various enzymes, such as glycolytic, glyconeogenic, lipogenic, and also proteolytic. Their effect appears to be a nonspecific type of inhibition. Further studies are required to determine their physiological relevance, if any.

Cooking↗
PubMed1975

Penicillium stoloniferum virus: altered replication in ultraviolet-derived mutants.

Phenotypic mutants of the wild type of Penicillium stoloniferum NRRL5267 were obtained from conidia exposed to ultraviolet light for 60 min (10% survival). Virus content of the wild type and of nine phenotypic mutants was determined by polyacrylamide gel electrophoresis. Four mutants had no detectable Penicillium stoloniferum virus F (PsV-F), whereas the other five had levels of PsV-F in the mycelium similar to the wild-type strain. All nine mutants and the wild type had comparable levels of Penicillium stoloniferum virus S (PsV-S). Maximum virus levels occurred after 9 days of submerged culture in a 2% yeast extract-15% sucrose medium. Virus replication in the fungal host continued after protein, RNA and DNA synthesis levelled off. Virus levels ranged from 85 to 150 E-260 units (extinction units at 260 nm in I cm cell) per 4-7 to 5-3 g dry weight of mycelium for the mutant strains compared to 106 E-260 units per 4-2 g dry weight of the wild-type strain.

Color↗
PubMed1975

Bright greenish-yellow fluorescence and aflatoxin in agricultural commodities.

The corn milling industry has widely accepted the presence of bright greenish-yellow fluorescence under a black light as a presumptive indicator of aflatoxin (a poison produced by the mold Aspergillus flavus). This test was applied to wheat, oats, barley, rice, coconut, white corn, yellow corn, peanuts, sorghum, and soybeans, and evaluated in the laboratory. Our study supported the use of bright greenish-yellow fluorescence as a presumptive test for aflatoxin in wheat, oats, barley, corn, and sorghum.

Aflatoxins↗