Inhibition of Aspergillus flavus growth by fractions of salt-extracted proteins from maize kernel

Neucere, Joseph N.; Zeringue, H. J.

doi:10.1021/jf00077a041

Cited by 12 publications

(14 citation statements)

References 7 publications

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“…Further, A. flavus did not exhibit hyphal rupture or hyphal elongation inhibition when treated with AFPs. A. flavus was inhibited by maize seed proteins and polysaccharides using the spore germination method (Neucere and Zeringue, 1987;Neucere and Godshall, 1991).…”

Section: Confirmation Of Afps In Column Eluantsmentioning

confidence: 99%

In Vitro Activity of Sorgum Seed Antifungal Proteins against Grain Mold Pathogens

Seetharaman

Whitehead

Keller

et al. 1997

J. Agric. Food Chem.

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Several sorghum seed antifungal proteins (AFP), including sormatin, chitinase, glucanase, and ribosome-inhibiting protein (RIP), were extracted, partially purified using sequential ammonium sulfate precipitation, and eluted from a CM-Sephadex column using a linear salt gradient. Eluted fractions were tested for bioactivity against Fusarium moniliforme, Curvularia lunata, and Aspergillus flavus using hyphal rupture, hyphal extension, and spore germination methods. A fraction containing several AFPs was most inhibitory against F. moniliforme, C. lunata, and A. flavus. Spore germination of all three species was markedly inhibited by 360 ppm of AFPs. The inhibitory effects were not observed when the protein fraction was boiled, suggesting the involvement of undenatured proteins. Hyphal elongation inhibition was the least sensitive assay to detect the inhibitory effects of AFPs on these fungi. F. moniliforme exhibited hyphal rupture at the growing tip at protein levels as low as 70 ppm. C. lunata required higher protein levels (70-360 ppm) and ruptured only at hyphal tips. A. flavus did not exhibit hyphal disruption when treated with AFPs.

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Section: Confirmation Of Afps In Column Eluantsmentioning

confidence: 99%

In Vitro Activity of Sorgum Seed Antifungal Proteins against Grain Mold Pathogens

Seetharaman

Whitehead

Keller

et al. 1997

J. Agric. Food Chem.

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“…An earlier in vitro study on antifungal properties of water/salt-soluble proteins in these two varieties of corn showed the complexity of the system (Neucere and Zeringue, 1987). Direct correlation between inhibition of fungal growth and lectin activity in one of the salt-eluted fractions was observed only in Yellow Creole, the yellow corn (resistant) variety.…”

Section: 22mentioning

confidence: 94%

Existence of chitinase activity in mature corn kernels (Zea mays L.)

Neucere¹,

Dischinger²

1991

J. Agric. Food Chem.

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Reducing infection by Aspergillus flauus group species that produce aflatoxins in corn is an area of intense interest. One speculation is that chitinase could be a resistance factor involved in inhibiting or reducing fungal growth. Mature kernels of yellow corn (A. flauus resistant) and white corn (A. flauus susceptible) were assayed for chitinase activity. Results showed higher activity in germ tissue than in the endosperm with disparity between the two varieties. The highest activity per quantity of protein was observed in the germ of white corn and in salt fractions from whole kernel corn precipitated with 20% ammonium sulfate. From gel permeation chromatography, major chitinase activity occurred in the fractions with molecular size ranging from 14 to 25 kDa. Isoelectric focusing on acrylamide gels showed major chitinase activity in protein zones at pH 3-4. These data provide evidence that the catalytic components exist in several isozyme forms that are acidic and highly associated in the native state.Several studies have shown that seeds and vegetative tissues of higher plants contain chitinases (Grassman et al., 1934; Powning and Irzykliewicz, 1965;Wargo, 1975; Boller, 1985; Broekaert et al., 1988). Studies with various model systems have shown that chitinases are also induced by pathogen attacks and chemical treatments that impart stress on plants (Boller et al., 1983;Metraux and Boller, 1986). All of these studies provide circumstantial evidence that chitinases exist in different forms in plants and may be somehow involved in host defense against fungal pathogens (Payne et al., 1990). Our interest in chitinases in corn arises from the critical problem of aflatoxin contamination caused by the fungi Aspergillus flauus and A. parasiticus. The complex relationship between fungal infection and aflatoxin formation is an area of intense research worldwide. Currently, one of the objectives in solving the problem is the identification of resistance genes that could be transferred within the species through classical breeding or genetic engineering. Hence, if intrinsic chitinase is indeed a pertinent resistance factor in corn, then appropriate strategies could be coordinated to improve the health and safety of this major crop.In this preliminary study, our objective was to develop a similarity profile of chitinase activity in the endosperm and the germ of two varieties of mature corn kernels. We chose kernels from open-pollinated varieties with extremes in aflatoxin contamination due to A. flavus infection, namely Yellow Creole (highly resistant) and Huffman (highly susceptible white endosperm variety) in field studies reported earlier (Zuber et al., 1983). Certain protein fractions from these two varieties were shown to have antifungal properties in an earlier study (Neucere and Zeringue, 1987). MATERIALS AND METHODS Extraction of Corn Tissues and Protein Fractionation.For preliminary experiments, kernels of the two varieties were sectioned by cutting the lower third of whole kernels, which included most of the ge...

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“…The meal was extracted with 200 ml hexane to remove neutral lipids and was then air-dried. Ten-gramme samples, in duplicate, of the dried meals were extracted with phosphate buffered saline as described previously [ 11] to remove the salt-soluble proteins. The residues were washed twice with 100 ml distilled water followed by centrifugation at 18000g for 30 min at 25 ~ Washed residues were extracted with 100 ml of 0.075 M NaOH, pH 11.2, and again centrifuged as before.…”

Section: Methodsmentioning

confidence: 99%

“…A recent study showed that salinesoluble proteins extracted from kernels of corn inhibited growth ofA. tiaras [ 11 ]; certain chromatographic fractions showed strong inhibition of fungal growth and a correlation between inhibition of fungal growth and lectin activity was observed in a highly resistant genotype.…”

Section: Introductionmentioning

confidence: 99%

“…This report describes antifungal properties of base-soluble proteins (BSP) and methanol-soluble polysaccharides (PS) derived from highly resistant (Yellow Creole) and highly susceptible (Huffman-white) genotypes of corn to A. flavus infection [11,18]. Bioassays of growth inhibition, a comparative profile of proteins by electrophoresis and sugar analyses are reported.…”

Section: Introductionmentioning

confidence: 99%

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Effects of base-soluble proteins and methanol-soluble polysaccharides from corn on mycelial growth of Aspergillus flavus

Neucere

Godshall

1991

Mycopathologia

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The antifungal activity of base-soluble proteins (BSP) and methanol-soluble polysaccharides (PS) from A. flavus resistant (Yellow Creole) and susceptible (Huffman) genotypes of corn were investigated by in vitro studies. Bioassays of fungal growth inhibition in agar media showed antifungal activity by proteins and polysaccharides only from the Huffman genotype. Microgramme quantities of protein and polysaccharides were required to retard fungal growth. The polysaccharides have molecular weights greater than 3.5 kilodaltons. Cathodic PAGE of native protein from the two genotypes showed six protein bands with differences in staining intensity of individual components. SDS-PAGE showed four distinct bands in Yellow Creole that were absent in Huffman. Both of the protein samples contained traces of carbohydrate. Analysis of hydrolyzed polysaccharide from the two genotypes showed different proportions of mannose and glucose.

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Inhibition of Aspergillus flavus growth by fractions of salt-extracted proteins from maize kernel

Cited by 12 publications

References 7 publications

In Vitro Activity of Sorgum Seed Antifungal Proteins against Grain Mold Pathogens

In Vitro Activity of Sorgum Seed Antifungal Proteins against Grain Mold Pathogens

Existence of chitinase activity in mature corn kernels (Zea mays L.)

Effects of base-soluble proteins and methanol-soluble polysaccharides from corn on mycelial growth of Aspergillus flavus

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