scholarly journals Distribution, Genetic Diversity and Biocontrol of Aflatoxigenic Aspergillus flavus in Serbian Maize Fields

Toxins ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 687
Author(s):  
Vanja Vlajkov ◽  
Mila Grahovac ◽  
Dragana Budakov ◽  
Marta Loc ◽  
Ivana Pajčin ◽  
...  

Maize is one of the leading export products in the Republic of Serbia. As a country where economic development depends on agriculture, maize production plays a critical role as a crop of strategic importance. Potential aflatoxin contamination of maize poses a risk to food and feed safety and tremendous economic losses. No aflatoxin contamination of maize samples harvested in 2019 and 2020 in different localities in the Republic of Serbia was detected by the Enzyme-Linked Immunosorbent Assay (ELISA) test and High-Performance Liquid Chromatography (HPLC) method. On the other hand, the Cluster Amplification Patterns (CAP) analyses of the isolated Aspergillus flavus strains from 2019 maize samples confirmed the presence of key biosynthesis genes responsible for aflatoxin production. Artificial inoculation and subsequent HPLC analysis of the inoculated maize samples confirmed the high capacity of the A. flavus strains for aflatoxin production, pointing to a high risk of contamination under favorable conditions. Prevention of aflatoxin contamination is primarily based on A. flavus control, where biocontrol agents play a significant role as sustainable disease management tools. In this study, antagonistic activity screening of the novel strains belonging to the Bacillus genus indicated superior suppression of A. flavus strains by two Bacillus strains isolated from the rhizosphere of Phaseolus vulgaris.

Animals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 166 ◽  
Author(s):  
Nimra Azeem ◽  
Muhammad Nawaz ◽  
Aftab Ahmad Anjum ◽  
Shagufta Saeed ◽  
Saba Sana ◽  
...  

Aflatoxin contamination in human food and animal feed is a threat to public safety. Aflatoxin B1 (AFB1) can be especially damaging to poultry production and consequently economic development of Pakistan. The present study assessed the in vitro binding of AFB1 by indigenously characterized probiotic lactobacilli. Six isolates (Lactobacillus gallinarum PDP 10, Lactobacillus reuetri FYP 38, Lactobacillus fermentum PDP 24, Lactobacillus gallinarum PL 53, Lactobacillus paracasei PL 120, and Lactobacillus gallinarum PL 149) were tested for activity against toxigenic Aspergillus flavus W-7.1 (AFB1 producer) by well diffusion assay. Only three isolates (PL 53, PL 120, and PL 149) had activity against A. flavus W-7.1. The ameliorative effect of these probiotic isolates on AFB1 production was determined by co-culturing fungus with lactobacilli for 12 days, followed by aflatoxin quantification by high-performance liquid chromatography. In vitro AFB1 binding capacities of lactobacilli were determined by their incubation with a standard amount of AFB1 in phosphate buffer saline at 37 °C for 2 h. AFB1 binding capacities of isolates ranged from 28–65%. Four isolates (PDP 10, PDP 24, PL 120, and PL 149) also ceased aflatoxin production completely, whereas PL 53 showed 55% reduction in AFB1 production as compared to control. The present study demonstrated Lactobacillus gallinarum PL 149 to be an effective candidate AFB1 binding agent against Aspergillus flavus. These findings further support the binding ability of lactic acid bacteria for dietary contaminants.


2020 ◽  
Vol 6 (4) ◽  
pp. 383
Author(s):  
Premila Narayana Achar ◽  
Pham Quyen ◽  
Emmanuel C. Adukwu ◽  
Abhishek Sharma ◽  
Huggins Zephaniah Msimanga ◽  
...  

Aspergillus species are known to cause damage to food crops and are associated with opportunistic infections in humans. In the United States, significant losses have been reported in peanut production due to contamination caused by the Aspergillus species. This study evaluated the antifungal effect and anti-aflatoxin activity of selected plant-based essential oils (EOs) against Aspergillus flavus in contaminated peanuts, Tifguard, runner type variety. All fifteen essential oils, tested by the poisoned food technique, inhibited the growth of A. flavus at concentrations ranging between 125 and 4000 ppm. The most effective oils with total clearance of the A. flavus on agar were clove (500 ppm), thyme (1000 ppm), lemongrass, and cinnamon (2000 ppm) EOs. The gas chromatography-mass spectrometry (GC-MS) analysis of clove EO revealed eugenol (83.25%) as a major bioactive constituent. An electron microscopy study revealed that clove EO at 500 ppm caused noticeable morphological and ultrastructural alterations of the somatic and reproductive structures. Using both the ammonia vapor (AV) and coconut milk agar (CMA) methods, we not only detected the presence of an aflatoxigenic form of A. flavus in our contaminated peanuts, but we also observed that aflatoxin production was inhibited by clove EO at concentrations between 500 and 2000 ppm. In addition, we established a correlation between the concentration of clove EO and AFB1 production by reverse-phase high-performance liquid chromatography (HPLC). We demonstrate in our study that clove oil could be a promising natural fungicide for an effective bio-control, non-toxic bio-preservative, and an eco-friendly alternative to synthetic additives against A. flavus in Georgia peanuts.


2013 ◽  
Vol 6 (1) ◽  
pp. 43-50 ◽  
Author(s):  
V. Aiko ◽  
A. Mehta

Cinnamon, cardamom, star anise and clove were studied for their effect on growth of Aspergillus flavus and aflatoxin B1 (AFB1) synthesis. The experiments were carried out in yeast extract sucrose culture broth as well as in rice supplemented with spices. AFB1 produced was analysed qualitatively and quantitatively using thin layer chromatography and high performance liquid chromatography, respectively. At a concentration of 10 mg/ml, cardamom and star anise did not exhibit any antifungal or anti-aflatoxigenic activity in culture broth, whereas cinnamon and clove inhibited A. flavus growth completely. The minimum inhibitory concentrations of cinnamon and clove were 4 and 2 mg/ml, respectively. Concentrations of cinnamon and clove below their minimum inhibitory concentrations showed enhanced fungal growth, while AFB1 synthesis was reduced. Clove inhibited the synthesis of AFB1 significantly up to 99% at concentrations ≥1.0 mg/ml. The spices also inhibited AFB1 synthesis in rice at 5 mg/g, although fungal growth was not inhibited. Clove and cinnamon inhibited AFB1 synthesis significantly up to 99 and 92%, respectively, and star anise and cardamom by 41 and 23%, respectively. The results of this study suggest the use of whole spices rather than their essential oils for controlling fungal and mycotoxin contamination in food grains.


1999 ◽  
Vol 65 (6) ◽  
pp. 2738-2740 ◽  
Author(s):  
Sui-Sheng T. Hua ◽  
James L. Baker ◽  
Melanie Flores-Espiritu

ABSTRACT The nor mutant of Aspergillus flavus has a defective norsolorinic acid reductase, and thus the aflatoxin biosynthetic pathway is blocked, resulting in the accumulation of norsolorinic acid, a bright red-orange pigment. We developed a visual agar plate assay to monitor yeast strains for their ability to inhibit aflatoxin production by visually scoring the accumulation of this pigment of the nor mutant. We identified yeast strains that reduced the red-orange pigment accumulation in the normutant. These yeasts also reduced aflatoxin accumulation by a toxigenic strain of A. flavus. These yeasts may be useful for reducing aflatoxin contamination of food commodities.


2002 ◽  
Vol 65 (12) ◽  
pp. 1984-1987 ◽  
Author(s):  
J. E. MELLON ◽  
P. J. COTTY

Soybean lines lacking lipoxygenase (LOX) activity were compared with soybean lines having LOX activity for the ability to support growth and aflatoxin B1 production by the fungal seed pathogen Aspergillus flavus. Whole seeds, broken seeds, and heat-treated (autoclaved) whole seeds were compared. Broken seeds, irrespective of LOX presence, supported excellent fungal growth and the highest aflatoxin levels. Autoclaved whole seeds, with or without LOX, produced good fungal growth and aflatoxin levels approaching those of broken seeds. Whole soybean seeds supported sparse fungal growth and relatively low aflatoxin levels. There was no significant difference in aflatoxin production between whole soybean seeds either with or without LOX, although there did seem to be differences among the cultivars tested. The heat treatment eliminated LOX activity (in LOX+ lines), yet aflatoxin levels did not change substantially from the broken seed treatment. Broken soybean seeds possessed LOX activity (in LOX+ lines) and yet yielded the highest aflatoxin levels. The presence of active LOX did not seem to play the determinant role in the susceptibility of soybean seeds to fungal pathogens. Seed coat integrity and seed viability seem to be more important characteristics in soybean seed resistance to aflatoxin contamination. Soybean seeds lacking LOX seem safe from the threat of increased seed pathogen susceptibility.


mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Milton T. Drott ◽  
Tatum R. Satterlee ◽  
Jeffrey M. Skerker ◽  
Brandon T. Pfannenstiel ◽  
N. Louise Glass ◽  
...  

ABSTRACT The apparent rarity of sex in many fungal species has raised questions about how much sex is needed to purge deleterious mutations and how differences in frequency of sex impact fungal evolution. We sought to determine how differences in the extent of recombination between populations of Aspergillus flavus impact the evolution of genes associated with the synthesis of aflatoxin, a notoriously potent carcinogen. We sequenced the genomes of, and quantified aflatoxin production in, 94 isolates of A. flavus sampled from seven states in eastern and central latitudinal transects of the United States. The overall population is subdivided into three genetically differentiated populations (A, B, and C) that differ greatly in their extent of recombination, diversity, and aflatoxin-producing ability. Estimates of the number of recombination events and linkage disequilibrium decay suggest relatively frequent sex only in population A. Population B is sympatric with population A but produces significantly less aflatoxin and is the only population where the inability of nonaflatoxigenic isolates to produce aflatoxin was explained by multiple gene deletions. Population expansion evident in population B suggests a recent introduction or range expansion. Population C is largely nonaflatoxigenic and restricted mainly to northern sampling locations through restricted migration and/or selection. Despite differences in the number and type of mutations in the aflatoxin gene cluster, codon optimization and site frequency differences in synonymous and nonsynonymous mutations suggest that low levels of recombination in some A. flavus populations are sufficient to purge deleterious mutations. IMPORTANCE Differences in the relative frequencies of sexual and asexual reproduction have profound implications for the accumulation of deleterious mutations (Muller’s ratchet), but little is known about how these differences impact the evolution of ecologically important phenotypes. Aspergillus flavus is the main producer of aflatoxin, a notoriously potent carcinogen that often contaminates food. We investigated if differences in the levels of production of aflatoxin by A. flavus could be explained by the accumulation of deleterious mutations due to a lack of recombination. Despite differences in the extent of recombination, variation in aflatoxin production is better explained by the demography and history of specific populations and may suggest important differences in the ecological roles of aflatoxin among populations. Furthermore, the association of aflatoxin production and populations provides a means of predicting the risk of aflatoxin contamination by determining the frequencies of isolates from low- and high-production populations.


2015 ◽  
Vol 8 (2) ◽  
pp. 235-244 ◽  
Author(s):  
K.E. Damann Jr.

The term ‘competitive exclusion’ involving physical blockage of growth or access of the toxigenic strain to the seed target has been used to describe the mechanism of biological control of aflatoxin contamination. However, recent evidence suggests that a form of intraspecific aflatoxin inhibition requiring growth of the competing strains together during the infection process in such a way that hyphae physically interact or touch is the trigger for preventing induction of aflatoxin synthesis. This direct touch-based inhibition of aflatoxin synthesis is posited to be the mechanistic basis of biological control in this system. Evidence for this idea comes from the published observations that co-culture of toxigenic and atoxigenic strains in a suspended disc system, in which the hyphae physically interact, prevents aflatoxin production. However, growth of the same strains in the same medium in the two compartments of a filter insert plate well system, separating the atoxigenic and toxigenic strains with a 0.4 μm or 3.0 μm filter, allows aflatoxin production approaching that of the toxigenic strain alone. When the strains are mixed and placed in both the insert and the well compartments, the intraspecific aflatoxin inhibition occurs as it did in the suspended disc culture system. This further suggests that neither nutrient competition nor soluble signal molecules, which should pass through the filter, are involved in intraspecific aflatoxin inhibition. When the two strains are separated by a 12 μm filter that would allow some passage of conidia or hyphae between the compartments the aflatoxin synthesis is approximately half that of the toxigenic strain alone. This phenomenon could be termed ‘competitive inclusion’ or ‘competitive phenotype conversion’. Work of others that relates to understanding the phenomenon is discussed, as well as an Aspergillus flavus population biology study from the Louisiana maize agro-ecosystem which has biological control implications.


2014 ◽  
Vol 668-669 ◽  
pp. 1550-1553 ◽  
Author(s):  
Chu Shu Zhang ◽  
Qin Zhao ◽  
Jian Xiong Feng ◽  
Jie Sun ◽  
Li Na Yu ◽  
...  

Single factor and Plackett-Burman design were used to determine the key environmental factors for Aspergillus flavus growth and aflatoxin production. The results showed that the key factors were culture time, moisture content. So Controling of moisture was crucial for Aflatoxin contamination prevention and control.


2004 ◽  
Vol 31 (2) ◽  
pp. 134-141 ◽  
Author(s):  
H. Q. Xue ◽  
T. G. Isleib ◽  
H. T. Stalker ◽  
G. A. Payne ◽  
G. OBrian

Abstract Anatoxins are carcinogenic and extremely toxic secondary metabolites produced primarily by two fungi, Aspergillus flavus Link ex Fries and A. parasiticus Speare. Elimination of aflatoxin contamination in peanut (Arachis hypogaea L.) is a high priority of the peanut industry. Resistant cultivars should be an effective and low-cost part of an integrated aflatoxin management program. To date, no cultivated peanut has been reported with stable high levels of resistance to aflatoxin production. Arachis species and interspecific tetraploid lines have been evaluated for resistance to several peanut diseases and insect pests, and highly resistant accessions have been reported. Seven accessions of A. cardenasii Krapov. and W.C. Gregory, 29 of A. duranensis Krapov. and W.C. Gregory, and 17 interspecific tetraploid lines derived from A. hypogaea × A. cardenasii were inoculated with A. flavus strain NRRL 3357 and analyzed for aflatoxin content after incubation. On average, A. duranensis and A. cardenasii accumulated significantly less aflatoxin than A. hypogaea checks. The mean difference between the two wild species was not significant. Arachis duranensis accessions PI 468319 (GKBSPSc 30073), PI 468200 (GKBSPSc 30064), and PI 262133 (GKP 10038 sl.); and A. cardenasii accessions PI 262141 (GKP 10017) and PI 475997 (KSSc 36018) had reduced levels of aflatoxin accumulation and should be valuable sources of resistance to aflatoxin contamination. Of the interspecific tetraploid lines, only GP-NC WS 2 supported aflatoxin production not significantly different from resistant parent A. cardenasii GKP 10017, and it appears to be a line with reduced capacity for aflatoxin accumulation.


Author(s):  
A.K. Bulashev ◽  

In veterinary practice, a large list of antibiotics is used as therapeutic and/or prophylactic agents.Some of them are used as stimulators of the growth and productivity of animals.However, non-observance of the rules for the use of antibiotics and / or timing of slaughter or obtaining milk leads to the intake of a residual amount of antibiotics into the human body with food and can cause various pathologies. The article provides an overview of research papers published in peer-reviewed journals from 2015 to the present on the development and improvement of methods for testing milk and meat for antibiotics. Based on the literature review and the results of his own study, the author of the article notes the advantages of enzyme-linked immunosorbent assay (ELISA) options over instrumental analytical methods, such as liquid chromatography with tandem mass spectrometry and high-performance liquid chromatography. However, due to the complexity of the analysis procedure, ELISA kits are not used in food safety laboratories in the Republic of Kazakhstan and other CIS countries. The article describes the state and prospects for the development of simple rapid tests to determine the maximum residue limit (MRL) for antibiotics in livestock products, based on the use of Lateral Flow Assay (LFA). Such tests, not inferior in their sensitivity to ELISA and surpassing it in cost, could be used not only in laboratory conditions, but also directly by food consumers, which will contribute to reliable protection of public health and the development of animal husbandry.


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