Paul E. Nelson

A review and update of animal toxicoses associated with fumonisin-contaminated feeds and production of fumonisins by Fusarium isolates

During the 1989 corn harvest season, numerous reports of equine leukoencephalomalacia (ELEM) outbreaks and a pulmonary edema (PPE) syndrome in swine from several regions of the United States were received by the National Veterinary Services Laboratories (NVSL), Ames, Iowa. Previous and concurrent research linked Fusarium moniliforme and fumonisin-contaminated feeds to both diseases. Chemical and mycological investigations revealed fumonisin B1 (FB1) concentrations of 20 to 360 ppm in suspect swine feeds and 8 to 117 ppm in suspect equine feeds. Nonproblem feeds contained concentrations below 8 ppm. Fusarium moniliforme and Fusarium proliferatum were isolated from both problem and nonproblem equine and swine feeds. When cultured on autoclaved corn, the F. moniliforme and F. proliferatum isolates produced respective FB1 and fumonisin B2 (FB2) that range from less than 5 to more than 2450 ppm and less than 5 to more than 1000 ppm, respectively. Isolates from both problem and nonproblem feeds produced high levels (greater than 500 ppm) in culture. Reported here is a review of chemical and mycological data resulting from the study of several cases of PPE and ELEM.

Taxonomy and biology of Fusarium moniliforme

Fusarium moniliforme is one of the most prevalent fungi associated with basic human and animal dietary samples such as corn. This fungus has been suspected of being involved in human and animal diseases since its original description. Fusarium moniliforme is in the section Liseola along with F. proliferatum, F. subglutinans, and F. anthophilum. Cultural mutation often occurs when F. moniliforme is grown on a medium rich in carbohydrates. Mutants may be either the mycelial or pionnotal type and often lose virulence and the ability to produce toxins. Toxins produced by F. moniliforme are fusaric acid, fusarins, gibberellins, moniliformin, and fumonisins. The fumonisins are produced most often when F. moniliforme grows on corn. Fusarium moniliforme causes ear rot and stalk rot of corn and infection of corn kernels by this fungus is widespread. Infection of developing corn kernels may occur through the silks, through holes and fissures in the pericarp or at points where the pericarp is torn by the emerging seedling, and as a result of systemic infection of the corn plant by F. moniliforme. These modes of infection as well as infestation of the kernel surface are important factors when considering the production of fumonisins in corn

Characterization of an Epizootic of Pulmonary Edema in Swine Associated with Fumonisin in Corn Screenings

In 1989, corn screenings were associated with acute interstitial pulmonary edema, hydrothorax, and death in swine. Attack rate was 5–50%, case fatality rate was 50–90%, and clinical course was 1–2 days. Screenings from farms with pigs affected with pulmonary edema contained 20–330 μg fumonisin B1 per gram. Screenings containing 92 μg fumonisin B1 per gram fed to weanling pigs caused pulmonary edema and death. Sterilized corn inoculated with Fusarium moniliforme and diluted 1:1 with clean corn contained fumonisin B, (17 μg/g) and caused acute pulmonary edema when fed for 5 days. Survivors developed subacute hepatotoxicosis with individual hepatocellular necrosis, hepatomegalocytosis, and increased numbers of mitotic figures. Similar liver lesions occurred in pigs given fumonisin B1 intravenously at 0.8 mg/kg body weight for 14 days.

FUSARIUM THAPSINUM (GIBBERELLA THAPSINA) : A NEW SPECIES IN SECTION LISEOLA FROM SORGHUM

A group of Fusarium strains first distin- guished by the production of a diffusing yellow pig- ment is now described as a separate species, Fusarium thapsinum. The teleomorph, Gibberella thapsina, can be formed under laboratory conditions by crossing strains of opposite mating type on carrot agar. Fusar- ium thapsinum was recovered from banana, maize, peanut and sorghum in Egypt, South Africa, the Phil- ippines, Thailand, and nine states in the United States. Members of this species are morphologically similar to Fusarium moniliforme (Gibberella fujikuroi mating population A), but the two groups are repro- ductively isolated and can be distinguished by other characters such as mycotoxins produced, isozyme polymorphism, electrophoretic karyotype, benomyl sensitivity, and differences in the sequence of the in- ternally transcribed spacer (ITS) region of the ribo-

Moniliformin Production In Fusarium Section Liseola

Fusarium cultures belonging to section Liseola were grown on corn, tested for toxicity to ducklings and the toxic strains analyzed for moniliformin content. The only existing culture of F. annulatum was non-toxic and did not produce moniliformin. The 149 cultures examined represented F. moniliforme, F. proliferatum, F. subglutinans, F. anthophilum, F. succisae and a sixth taxon of uncertain identity isolated from rice with Bakanae disease. The single toxic isolate of F. succisae did not produce mo? niliformin. The five other taxa all contained at least some moniliformin-producing strains, but differed in the percentage of strains that produced moniliformin as well as the amounts produced. Moniliformin production by F. proliferatum and F. anthophilum is reported for the first time.

Spermine Synthesis Is Required for Normal Viability, Growth, and Fertility in the Mouse

Spermidine is essential for viability in eukaryotes but the importance of the longer polyamine spermine has not been established. Spermine is formed from spermidine by the action of spermine synthase, an aminopropyltransferase, whose gene (SpmS) is located on the X chromosome. Deletion of part of the X chromosome that include SpmS in Gy mice leads to a striking phenotype in affected males that includes altered phosphate metabolism and symptoms of hypophosphatemic rickets, circling behavior, hyperactivity, head shaking, inner ear abnormalities, deafness, sterility, a profound postnatal growth retardation, and a propensity to sudden death. It was not clear to what extent these alterations were due to the loss of spermine synthase activity, since this chromosomal deletion extends well beyond the SpmS gene and includes at least one other gene termed Phex. We have bred the Gy carrier female mice with transgenic mice (CAG/SpmS mice) that express spermine synthase from the ubiquitous CAG promoter. The resulting Gy-CAG/SpmS mice had extremely high levels of spermine synthase and contained spermine in all tissues examined. These mice had a normal life span and fertility and a normal growth rate except for a reduction in body weight due to a loss of bone mass that was consistent with the observation that the derangement in phosphate metabolism is due to the loss of the Phex gene and was not restored. These results show that spermine synthesis is needed for normal growth, viability, and fertility in male mice and that regulation of spermine synthase content is not required.

The Effect of Environment on Sexual Reproduction of Gibberella Zeae

Optimal temperatures for perithecial production and ascospore discharge in Gibberella zeae differed significanly. Numbers of perithecia increased with increasing temperature to ca. 29 C, and decrea...

Characterization, geographic distribution and ecology of Fusarium crookwellense sp.nov.

Fusarium crookwellense is described and illustrated. Initial isolates were from potato tubers from the Crookwell area of New South Wales, Australia. Additional isolates have been recovered from wheat, corn, barley, Paspalum sp., Pinus sp. and debris from temperate and tropical pasture soils from various locations in Eastern Australia. Isolates from a variety of host plants and debris from soil have been obtained from the U.S.A., South Africa, France, Colombia, and China. Descriptions of the sporodochial cultures and macroconidia are given and compared to F. sambucinum, F. culmorum, F. robustum , and F. graminearum. F. crookwellense is generally more abundant in temperate high rainfall or irrigated areas.

Distribution of Fusarium species in sections Roseum, Arthrosporiella, Gibbosum and Discolor recovered from grassland, pasture and pine nursery soils of eastern Australia

Fusarium species in sections Roseum, Arthrosporiella, Gibbosum, and Discolor were common in grassland, pasture, and pine nursery soils of eastern Australia. The grasslands consisted of grazing land...

Fusarium species isolated from soil samples collected at different altitudes in the Transkei, southern Africa

Fusarium species were isolated from soil samples and soil debris obtained at altitudes of 1400, 1100, 800, 500, 250, and 0 m in the Republic of Transkei. Nineteen species of Fusarium were isolated representing sections Eupionnotes, Sporotrichiella, Discolor, Gibbosum, Arthrosporiella, Liseola, Elegans, Martiella, and Lateritium. Fusarium oxysporum, F. equiseti, F. semitectum, F. nygamai, and F. solani were isolated most frequently and F. oxysporum was the predominant species isolated from all samples. Other species recovered were F. chlamydosporum, F. merismoides, F. lateritium, F. culmorum, F. compactum, F. dlamini, F. poae, F. proliferatum, F. moniliforme, F. graminearum, F. sambucinum, F. napiforme, and three unknown populations. Using Simpsons index, the diversity indices calculated for Fusarium species from debris and soil from each sampling site indicate that overall debris was a greater source of species diversity than soil. Diversity indices calculated for each altitude sample and each isolation technique showed that the sea level site yielded the most diverse population.