Strains Of Fusarium Moniliforme Research Articles

Conversion of various aromatic compounds by resting cells of Fusarium moniliforme strain MS31

Resting cells of Fusarium moniliforme strain MS31 convert propylbenzene to 1-phenylpropanol with high regio- and stereospecificity. To elucidate the scope of substrate acceptability by the fungus, we used various aromatic compounds for the bioconversion. The fungus hydroxylated various alkylbenzenes at the benzylic position to produce optically active alcohols. Butylbenzene was converted to nonbenzylic alcohols. In all cases, the R absolute configuration of products was more abundant. Aromatic compounds with linear side chains and (1-methylethyl)benzene were converted to their corresponding alcohols with an enantiomeric excess of 94% to 100%. Further oxidation of the alcohols was detected, but it was weak.

The Antifungal Activity of Natamycin toward Molds Isolated from Commercially Manufactured Poultry Feed

The antifungal activity of natamycin, a polyene antifungal compound, was evaluated on molds isolated from commercial poultry feed. The antifungal activity was measured by determination of the minimal inhibitory concentration (MIC) for natamycin on molds growing on semisolid microbiological medium (potato dextrose agar) containing pure natamycin at concentrations ranging from 0 to 200 mg/liter. Natamycin exhibited a high degree of antifungal activity against the 191 isolates of aspergilli used in this study, with average MIC values ranging from 5.08 to 40.1 mg/liter for Aspergillus fumigatus and Aspergillus parasiticus, respectively. Natamycin was also equally effective in inhibiting the growth of nonaflatoxigenic compared with aflatoxigenic isolates of Aspergillus flavus and A. parasiticus. Natamycin was also efficacious against molds other than aspergilli, with MIC values ranging from 2.15 to 5.80 mg/liter for Paecilomyces and Rhizopus spp., respectively. Natamycin exhibited apparent sporicidal activity against spores of toxigenic strains of Fusarium moniliforme and A. parasiticus but not Penicillium rubrum. This sporicidal activity was evident only when spores were exposed to an in vitro concentration of natamycin of 25 mg/liter or higher for a period of time of at least 12 hr. The growth inhibiting activity of natamycin was more pronounced compared with the sporicidal activity.

Efficacy of Burkholderia cepacia MCI 7 in disease suppression and growth promotion of maize

Repeated greenhouse experiments were performed to evaluate the ability of a maize-rhizosphere isolate of Burkholderia cepacia, applied as a seed coating, to promote maize growth in both uninfested soil and soil infested with a maize pathogenic strain of Fusarium moniliforme, and to displace or negatively affect the population of F. moniliforme throughout plant growth. Results demonstrated that the B. cepacia strain MCI 7 is a promising plant-growth-promoting inoculant for maize. In repeated greenhouse trials, bacterization of maize seeds with B. cepacia MCI 7 resulted in a significant (P<0.05) increase of maize plant growth in both uninfested soil and soil infested with F. moniliforme ITEM-504, as compared to uninoculated plants. Moreover, B. cepacia MCI 7 was able to negatively affect the rhizoplane colonization of F. moniliforme that showed significantly (P<0.05) lower values of population density throughout plant growth, as compared with respective values observed in the root system of uninoculated plants. The effect on plant growth following introduction of B. cepacia MCI 7 into the maize rhizosphere has also been investigated using two corn cultivars differing in their degree of resistance to Fusarium. Results showed that B. cepacia MCI 7 was able to determine an increased growth response (P<0.05) of the two corn cultivars in both uninfested soil and soil infested with F. moniliforme.

Culture medium for amylase production by toxigenic fungi

Mycelial growth and amylase production by a mycotoxigenic strain of Fusarium moniliforme and Aspergillus flavus were evaluated in a culture medium containing starch, glycerol, wheat bran or corn. With emphasis on corn, different fractions composed by germ, degermed seed, starch, milky stage corn and the respective starch or supernatant fraction were analyzed for F. moniliforme growth . The medium composed of milky stage corn supernatant promoted the best mycelial growth (p&lt;0.05), and it was used to prepare amylase production medium in the next step. The medium composed with 2% ground corn in milky stage corn supernatant (350g of milky stage corn blended with 250mL water and centrifuged) promoted the highest amylase production, which was at the 10th day of fermentation, both for F. moniliforme (42.32U/mL) and A. flavus (4,745.54U/mL).

Use of ion-exchange chromatography coupled with TLC-laser scanning densitometry for the quantitation of fumonisin B 1

A simple TLC-Laser scanning densitometric (TLC-LSD) method was developed for the quantitation of fumonisin B 1 (FB 1) isolated from solid media cultures (corn) and liquid media cultures of toxigenic Fusarium moniliforme strains ( F. moniliforme MRC 826, F. moniliforme 4223 and F. moniliforme 2927)). FB 1 was isolated from the cultures by solvent extraction (methanol:water, 3:1) and purified in a single step by ion-exchange chromatography using Dowex-1. FB 1 in the purified extracts was detected by TLC analysis using p-anisaldehyde as a post-chromatographic derivatizing agent. The major toxin identified was FB 1 ( R f 0.51) along with traces of FB 2 ( R f 0.57) and FB 3 ( R f 0.60) based on their comparison with the reference standard fumonisins. The sensitivity of the TLC-LSD method for the quantitation of FB 1 was found to be 500 ng g −1. The linear regression analysis performed for the quantitation of FB 1 by the TLC-LSD method showed a correlation coefficient ( r) value of 0.9. Spiking studies revealed the recovery of standard FB 1 (5 and 10 μg g −1) loaded on to Dowex-1 in the range of 87–96%. The purity of FB 1 purified from the cultures was determined by the two-dimensional TLC analysis. Two-dimensional TLC-analysis of the purified FB 1 revealed the purity to be greater than 85%. The method developed may find wide application in the environmental monitoring of the FB 1 contaminations in the various agricultural commodities and screening fumonisin producing toxigenic strains of F. moniliforme.

Rapid purification of fumonisins and their hydrolysis products with solid-phase extraction columns.

Fumonisins B(3) and B(4) (FB(3) and FB(4)) were recovered from the 50:50 acetonitrile/water extract of corn cultures of a strain of Fusarium moniliforme that does not make FB(1) or FB(2) by stirring the extract with IRA-68, a weak anion-exchange resin. The fumonisins were desorbed with 5% acetic acid in the same solvent. After dilution with water, the desorbed fumonisins were separated into FB(3) (FB(3) and FA(3)) and FB(4) (FB(4), FC(4), and FA(4)) fractions with a tC(18) solid-phase extraction (SPE) cartridge. The FB(3) fraction was then separated into FB(3) and FA(3) by using an NH(2) SPE cartridge and eluting with 5% acetic acid and increasing amounts of acetonitrile in water. Finally, FB(1) and FA(3) were hydrolyzed with calcium hydroxide. After recovery from the reaction mixture using a tC(18) cartridge, the hydrolyzed and partially hydrolyzed analogues were separated and the unreacted fumonisins recovered by using an NH(2) cartridge, initially in the normal-phase mode with increasing amounts of water in acetonitrile and then in the reversed-phase mode after the addition of 5% acetic acid to the solvent and eluting in the reverse order.

Distribution of Fumonisins in Maize Ears Infected with Strains of Fusarium moniliforme that Differ in Fumonisin Production.

Strains of Fusarium moniliforme (Gibberella fujikuroi mating population A) that differ in fu-monisin production in vitro were previously identified in a Kansas field population. One strain that produced high levels of fumonisins and two strains that produced very low levels of fu-monisins were applied to maize kernels at planting at the Rocky Ford Farm near Manhattan, Kansas. The distribution of fumonisins in symptomatic and symptomless kernels from individual harvested ears was determined by high performance liquid chromatography, and the distribution of the three applied strains in the kernels was determined by vegetative compatibility group analysis. Both symptomatic and symptomless kernels were extensively colonized with F. moniliforme, but the highest levels of fumonisins were in the symptomatic kernels. All three applied strains were recovered from kernels in 1993, and two of them were recovered from kernels in 1994. However, a high frequency of ear and kernel infection with a strain that produced little fumonisin in vitro did not consistently decrease the level of fumonisins. The frequency of infection with fumonisin low-producing strains may have been too low for competitive exclusion of naturally occurring fumonisin high-producing strains. Also, strains that are low-fumonisin producers under laboratory conditions may be high producers in the field.

Fumonisin B1 contamination of maize and experimental acute fumonisin toxicosis in pigs.

The fumonisin B1 content of 69 visibly mouldy and 23 mould-free maize samples grown in Hungary in 1993-1995 was determined by high-performance liquid chromatography (HPLC). Fumonisin B1 was found to occur in 70-73% of the mouldy samples. The mycotoxin level increased from year to year: the highest fumonisin B1 concentration was 75.1 mg/kg. The samples that were mould-free on visual inspection showed a much lower prevalence of fumonisin B1 contamination (30%) and contained fumonisin B1 in markedly lower concentrations (average, 1.52 mg/kg; maximum concentration, 5.1 mg/kg). Using the Fusarium moniliforme strain designated 14/A, isolated from the sample that had the highest mycotoxin concentrations, fumonisin B1 toxin was produced on maize by an internationally accepted procedure. Subsequently, two weaned piglets were fed a diet containing 330 mg fumonisin B1 per kg of feed. The experimental animals developed hydrothorax and pulmonary oedema, and died in 5-6 days. The clinical symptoms and pathological lesions were consistent with those of porcine pulmonary oedema (PPE) diagnosed in the USA in 1989-1990, as well as with those of a disease entity that had already been described in Hungary in the 1950s as the so-called fattening or unique pulmonary oedema of pigs but considered to be of unknown aetiology. The results of the feeding trial confirm that this pig disease, which has occurred in Hungary for a long time, is caused by the mycotoxin fumonisin B1.

Dimorphic fungus characteristic of fumonisin-producing strains of Fusarium moniliforme from Zhejiang.

Fusarium moniliforme and its fumonisins have been shown to be carcinogenic in lab animals and have been linked to high incidences of human esophageal cancer. In this study we report the dimorphic fungus characteristic of fumonisin-producing strains of F. moniliforme from foodstuffs in Zhejiang, China. All of the twenty strains of F. moniliforme shown produce fumonisin B1 475.9-6322.2 micrograms/g in corn medium. These strains of F. moniliforme form yeast-like colonies in Sabouraud's agar plates contained 9% NaCl at 37 degrees C incubator and shows mostly budding reproduction. In blood agar plates these strains of F. moniliforme appear grass-green haemolytic reactions. This is the first report that yeast-like growth, dimorphic pathogenic fungus feature is found in F. moniliforme. These results suggest that it is also important to program epidemiological surveys of F. moniliforme as a primary pathogenic fungus, while proceeding to produce mycotoxins of F. moniliforme in food hygiene.

Production of Fumonisins B1 and B2 by Toxinogenics Strains of Fusarium moniliforme in Corn Cultures

Production of Fumonisins B1 and B2 by Toxinogenics Strains of Fusarium moniliforme in Corn Cultures

The inducible and cytochrome P450-containing dehydroepiandrosterone 7α-hydroxylating enzyme system of Fusarium moniliforme

7α-Hydroxylation of DHEA by Fusarium moniliforme was investigated with regard to inducibility and characterization of the responsible enzyme system. Using GC/MS, the 7-hydroxylated metabolites of DHEA produced after biotransformation by Fusarium moniliforme mycelia were identified. The strain of Fusarium moniliforme hydroxylated DHEA predominantly at the 7α-position, with minor hydroxylation occurring at the 7β-position. Constitutive 7α-hydroxylation activity was low, but DHEA induced the enzyme complex responsible for 7α-hydroxylation via an increase in protein synthesis. DHEA 7α-hydroxylase was found to be mainly microsomal, and the best production yields of 7α-hydroxy-DHEA (28.5 ± 3.51 pmol/min/mg protein) were obtained with microsomes prepared from 18-h-induced mycelia. Kinetic parameters ( K M=1.18 ± 0.035 μM and V max=909 ± 27 pmol/min/mg protein) were determined. Carbon monoxide inhibited 7α-hydroxylation of DHEA by microsomes of Fusarium moniliforme. Also, exposure of mycelia to DHEA increased microsomal P450 content. These results demonstrated that: (i) DHEA is 7α-hydroxylated by microsomes of Fusarium moniliforme; (ii) DHEA induces Fusarium moniliforme 7α-hydroxylase; (iii) this enzyme complex contains a cytochrome P450.

Study of the biosynthesis of fumonisins B1, B2 and B3 by different strains of Fusarium moniliforme.

The relationship between fungal growth and the production of fumonisin on maize grain by 25 strains of Fusarium moniliforme of different origins has been investigated. Although sporulation was essentially the same for all the strains (about 10(8) propagules g-1 dry matter), ergosterol assays revealed marked variations in fungal biomass. All strains studied produced highly variable amounts of fumonisin B1, the highest levels being observed in strains of ergosterol content above 400 micrograms g-1. However, no correlation could be established between the synthesized biomass and the quantity of fumonisins produced. We verified that ergosterol is an indicator of mycelial growth, and therefore of the potential toxicity of the analysed grain.

Production of fusaric acid by Fusarium species

Fusaric acid is a mycotoxin with low to moderate toxicity, which is of concern since it might be synergistic with other cooccurring mycotoxins. Fusaric acid is widespread on corn and corn-based food and feeds and is frequently found in grain, where Fusarium spp. are also isolated. We surveyed 78 strains of Fusarium moniliforme, F. crookwellense, F. subglutinans, F. sambucinum, F. napiforme, F. heterosporum, F. oxysporum, F. solani, and F. proliferatum for their ability to produce fusaric acid. Strains in Fusarium section Liseola also were assigned to mating population of the Gibberella fujikuroi species complex. The fungi could be divided into three classes, low (< 100 micrograms/g), moderate (100 to 500 micrograms/g), and high (> 500 micrograms/g), based on the amounts of this mycotoxin produced in culture on autoclaved corn. Strains of mating populations C from rice consistently produced moderate to high concentrations of fusaric acid. Two isolates, one each from mating populations C and D, produced fusaric acid in excess of 1,000 micrograms/g of corn. No isolates of any of the Fusarium species examined were negative for the production of fusaric acid on autoclaved corn.

Screening of microorganisms for biodegradation of poly(lactic-acid) and lactic acid-containing polymers.

The ability of some microorganisms to use lactic acid stereocopolymers and copolymers with glycolic acid as sole carbon and energy sources was studied under controlled or natural conditions. First, 14 filamentous fungal strains were tested in liquid cultures, adopting total lactic acid consumption, nitrogen source exhaustion, and maximal biomass production as selection criteria. Two strains of Fusarium moniliforme and one strain of Penicillium roqueforti were able to totally assimilate DL-lactic acid, partially soluble racemic oligomers (MW = 1,000), and the nitrogen source. Only one strain of F. moniliforme was able to grow on a poly(lactic acid)-glycolic acid copolymer (MW = 150,000) after 2 months of incubation at 28 degrees C on synthetic agar medium. Mycelium development was examined by scanning electron microscopy. F. moniliforme filaments were observed to grow not only at the copolymer surface but also through the bulk of the copolymer. In a second approach, plates made of a racemic poly(lactic acid) were buried in the soil before being incubated in petri dishes containing mineral agar medium under controlled conditions. Five strains of different filamentous fungi were isolated, and their ability to assimilate racemic poly(lactic acid) oligomers was tested in liquid cultures.

Mycoflora and fumonisin-producing strains of Fusarium moniliforme in mixed poultry feeds and component raw material.

In a survey of the mycoflora and mycotoxins in foods and feeds, 66 samples of mixed poultry feeds and some component raw materials were investigated. Fungal counts ranged from < 10(2) to 1.3 x 10(6) CFU/g. Fusarium spp. counts ranged from 10(2) to 1.0 x 10(6) CFU/g. The fusarium spp. strains isolated were screened for their potential to produce fumonisin B1 (FB1) and fumonisin B2 (FB2) in maize cultures. Samples and maize cultures were analysed for FB1 and FB2 using TLC and fluorescamine-derivative HPLC. No fumonisins were detected in the samples (< 6 ppm). Fusarium moniliforme was isolated in 59.1% of samples, and 97.4% of the strains produced FB1 and 79.4% of strains produced FB2 in maize cultures. Some isolates produced higher FB1 and FB2 levels than the reference strain F. moniliforme MRC 826.

Fusarium polycaprolactone depolymerase is cutinase

Polycaprolactone (PCL), a synthetic polyester, is degraded by a variety of microorganisms, including some phytopathogens. Many phytopathogens secrete cutinase, a serine hydrolase that degrades cutin, the structural polymer of the plant cuticle. We compared wild-type strains and a cutinase-negative gene replacement mutant strain of Fusarium solani f. sp. pisi (D. J. Stahl and W. Schäfer, Plant Cell 4:621-629, 1992) and a wild-type strain of Fusarium moniliforme to show that Fusarium cutinase is a PCL depolymerase. The wild-type strains, but not the mutant strain, (i) degraded PCL and used it as a source of carbon and energy, (ii) showed induction of secreted PCL depolymerase and an esterase activity of cutinase when grown in the presence of cutin, and (iii) showed induction of PCL depolymerase and an esterase activity of cutinase when grown in the presence of a hydrolysate of PCL, which contains PCL oligomers that are structurally similar to the natural inducers of cutinase. These results together with other details of regulation and conditions for optimal enzyme activity indicate that the Fusarium PCL depolymerase, required for degradation and utilization of PCL, is cutinase.

Rapid Purification of Fumonisins B3 and B4 with Solid Phase Extraction Columns

A simple method was developed to isolate fumonisins B3 and B4 (FB3 and FB4) from cultures of a novel strain of Fusarium moniliforme which produces FB3 and FB4 but does not make FB1 or FB2. Undiluted extract was loaded onto a 10 g NH2 solid phase extraction cartridge, and the fumonisins were eluted with 5% acetic acid in methanol. The eluate was diluted with 1.5 vol of water and loaded onto a 10 g tC18 cartridge. The fumonisins were eluted with increasing amounts of acetonitrile in water. Complete separation was obtained between the FB3 (277 mg) and FB4 (62 mg) fractions. The fractions were analyzed for purity by three methods: fluorescence detection of the OPA derivatives, evaporative light-scattering detection of the underivatized fumonisins, and electrospray-MS. The fractions from the combined NH2/tC18 method contained more than 90% fumonisins. Recovery of the fumonisins from the extracts exceeded 95%. Keywords: Fumonisins; Fusarium moniliforme; corn; mycotoxins; isolation

Fertility ofFusarium moniliforme from maize and sorghum related to fumonisin production in Italy

Forty-three strains of Fusarium moniliforme isolated from infected maize and sorghum plants in Italy were assayed for their ability to produce fertile crosses with "A" and "F" mating population tester strains, in relation to their ability to produce fumonisins on maize substrate. Most of the strains isolated from maize (ear and stalk rot and maize-based feed), producing fumonisin B1 (FB1) and B2 (FB2) (up to 4,100 and 855 mg/kg, respectively), belonged to the "A" mating population. All of the strains isolated from sorghum belonged to the "F" mating population and produced little or no FB1 and FB2. This is the first report of the occurrence of mating population "F" in Europe. Our data on strains from Italy are consistent with previous studies from the United States that found significant differences in sexual fertility and fumonisin production between strains from maize and sorghum.

Occurrence of fumonisins in Europe and the BCR--measurements and testing projects.

Fumonisins are mycotoxins mainly produced by Fusarium moniliforme, one of the most prevalent seed-borne fungi of maize. Strains of Fusarium moniliforme isolated from cereals in Europe produced in cultures high levels (up to 4 mg/g) of fumonisins B1 and B2 (FB1 and FB2). FB1 and FB2 have been found in maize and maize-based foods and feeds in most European countries. In Italy these mycotoxins have been directly involved in a fatal outbreak of equine leukoencephalomalacia, and have been found at different levels in most maize-based food products, including polenta--a staple food in a region with high incidence of esophageal cancer. The European Commission, Community Bureau of Reference (BCR) and Measurements and Testing Programme (M&T), has undertaken two consecutive intercomparison studies, involving over 20 laboratories from 12 European countries, to improve the quality of fumonisins analysis at European level. The first study consisted in the evaluation of the determination of fumonisins in an unknown solution, while the second one involved the analytical methodology for fumonisins in contaminated and blank maize samples. A definite improvement in the performance of the different laboratories has been observed in the second study. In view of the production of reference materials certified for their fumonisins contents, new analytical procedures need to be developed.

Fumonisin Production in Corn by Toxigenic Strains of Fusarium moniliforme and Fusarium proliferatum

The fungi Fusarium moniliforme Sheldon and Fusarium proliferatum (Matsushima) Nirenberg produce a series of toxins on corn which include the fumonisins of which fumonisin B1 and B2 are considered to have cancer promoting activity. Both fungi produce similar ratios of the fumonisins B1 to B2. Other mycotoxins produced include moniliformin, fusarin C and fusaric acid. Fumonisin B1 has been shown to be responsible for most of the toxicological affects observed from ingesting corn infected by toxigenic isolates of these fungi. The distribution of the two fungi is generally similar, although F. proliferatum is isolated more frequently from sorghum than corn. They occur worldwide on other food crops, such as rice, sorghum, millet, several fruits and vegetables. Both fungi are ear rot pathogens of corn, thus, mycotoxin production occurs under field conditions, although it also may occur in storage. One or both fungi may have a frequency of occurrence of 90% or higher in corn; 90% of the F. moniliforme isolates produce the fumonisins. On corn and corn products the range of concentrations reported is 0.3 to 330 μg/g of corn-based product. These concentrations include both corn-based animal feed and human foods.