scholarly journals Selection of Atoxigenic Aspergillus flavus for Potential Use in Aflatoxin Prevention in Shandong Province, China

2021 ◽  
Vol 7 (9) ◽  
pp. 773
Author(s):  
Jia Xu ◽  
Peng Wang ◽  
Zehua Zhou ◽  
Peter John Cotty ◽  
Qing Kong
Keyword(s):  
Aspergillus Flavus ◽  
Filamentous Fungus ◽  
Culture Media ◽  
Domestic Animals ◽  
Aflatoxin Contamination ◽  
Shandong Province ◽  
Laboratory Studies ◽  
Competitive Displacement ◽  
Potential Use ◽  
Selection Of

Aspergillus flavus is a common filamentous fungus widely present in the soil, air, and in crops. This facultative pathogen of both animals and plants produces aflatoxins, a group of mycotoxins with strong teratogenic and carcinogenic properties. Peanuts are highly susceptible to aflatoxin contamination and consumption of contaminated peanuts poses serious threats to the health of humans and domestic animals. Currently, the competitive displacement of aflatoxin-producers from agricultural environments by atoxigenic A. flavus is the most effective method of preventing crop aflatoxin contamination. In the current study, 47 isolates of A. flavus collected from peanut samples originating in Shandong Province were characterized with molecular methods and for aflatoxin-producing ability in laboratory studies. Isolates PA04 and PA10 were found to be atoxigenic members of the L strains morphotype. When co-inoculated with A. flavus NRRL3357 at ratios of 1:10, 1:1, and 10:1 (PA04/PA10: NRRL3357), both atoxigenic strains were able to reduce aflatoxin B1 (AFB1) levels, on both culture media and peanut kernels, by up to 90%. The extent to which atoxigenic strains reduced contamination was correlated with the inoculation ratio. Abilities to compete of PA04 and PA10 were also independently verified against local aflatoxin-producer PA37. The results suggest that the two identified atoxigenic strains are good candidates for active ingredients of biocontrol products for the prevention of aflatoxin contamination of peanuts in Shandong Province.

Identification of Aspergillus flavus Isolates as Potential Biocontrol Agents of Aflatoxin Contamination in Crops

2013 ◽  
Vol 76 (6) ◽  
pp. 1051-1055 ◽  
Author(s):  
L. J. ROSADA ◽  
J. R. SANT'ANNA ◽  
C. C. S. FRANCO ◽  
G. N. M. ESQUISSATO ◽  
P. A. S. R. SANTOS ◽  
...  
Keyword(s):  
Biological Control ◽  
Aspergillus Flavus ◽  
Filamentous Fungus ◽  
Microscopic Examination ◽  
Genetic Recombination ◽  
Aflatoxin Contamination ◽  
Biocontrol Agents ◽  
Biological Control Agents ◽  
Nit Mutants ◽  
The Stability

Aspergillus flavus, a haploid organism found worldwide in a variety of crops, including maize, cottonseed, almond, pistachio, and peanut, causes substantial and recurrent worldwide economic liabilities. This filamentous fungus produces aflatoxins (AFLs) B1 and B2, which are among the most carcinogenic compounds from nature, acutely hepatotoxic and immunosuppressive. Recent efforts to reduce AFL contamination in crops have focused on the use of nonaflatoxigenic A. flavus strains as biological control agents. Such agents are applied to soil to competitively exclude native AFL strains from crops and thereby reduce AFL contamination. Because the possibility of genetic recombination in A. flavus could influence the stability of biocontrol strains with the production of novel AFL phenotypes, this article assesses the diversity of vegetative compatibility reactions in isolates of A. flavus to identify heterokaryon self-incompatible (HSI) strains among nonaflatoxigenic isolates, which would be used as biological controls of AFL contamination in crops. Nitrate nonutilizing (nit) mutants were recovered from 25 A. flavus isolates, and based on vegetative complementation between nit mutants and on the microscopic examination of the number of hyphal fusions, five nonaflatoxigenic (6, 7, 9 to 11) and two nontoxigenic (8 and 12) isolates of A. flavus were phenotypically characterized as HSI. Because the number of hyphal fusions is reduced in HSI strains, impairing both heterokaryon formation and the genetic exchanges with aflatoxigenic strains, the HSI isolates characterized here, especially isolates 8 and 12, are potential agents for reducing AFL contamination in crops.

Reduction in Aflatoxin Content of Maize by Atoxigenic Strains of Aspergillus flavus

1991 ◽  
Vol 54 (8) ◽  
pp. 623-626 ◽  
Author(s):  
ROBERT L. BROWN ◽  
PETER J. COTTY ◽  
THOMAS E. CLEVELAND
Keyword(s):  
Biological Control ◽  
Aspergillus Flavus ◽  
Aflatoxin Contamination ◽  
Biological Control Agents ◽  
Field Plot ◽  
Toxigenic Strain ◽  
Aflatoxin Content ◽  
Potential Use

In field plot experiments, an atoxigenic strain of Aspergillus flavus interfered with preharvest aflatoxin contamination of corn when applied either simultaneously with or one day prior to a toxigenic strain. The atoxigenic strain reduced preharvest aflatoxin contamination 80 to 95%. The atoxigenic strain was also effective in reducing postharvest aflatoxin contamination caused by both an introduced toxigenic strain and by strains resident on the kernels. The results suggest that atoxigenic strains of A. flavus may have potential use as biological control agents directed at reducing both preharvest and postharvest aflatoxin contamination of corn.

scholarly journals Revisiting an Aspergillus flavus Strain Isolated from an Egyptian Sugarcane Field in 1930

2020 ◽  
Vol 8 (11) ◽  
pp. 1633
Author(s):  
Mohamed F. Abdallah ◽  
Kris Audenaert ◽  
Sarah De Saeger ◽  
Jos Houbraken
Keyword(s):  
Aspergillus Flavus ◽  
Short Communication ◽  
Aflatoxin Contamination ◽  
Type B ◽  
Prevention Strategies ◽  
Sugarcane Field ◽  
Host Pathogen Interaction ◽  
Sugarcane Crop ◽  
Insight Into ◽  
Shed Light

The aflatoxin type B and G producer Aspergillus novoparasiticus was described in 2012 and was firstly reported from sputum, hospital air (Brazil), and soil (Colombia). Later, several survey studies reported the occurrence of this species in different foods and other agricultural commodities from several countries worldwide. This short communication reports on an old fungal strain (CBS 108.30), isolated from Pseudococcus sacchari (grey sugarcane mealybug) from an Egyptian sugarcane field in (or before) 1930. This strain was initially identified as Aspergillus flavus; however, using the latest taxonomy schemes, the strain is, in fact, A. novoparasiticus. These data and previous reports indicate that A. novoparasiticus is strongly associated with sugarcane, and pre-harvest biocontrol approaches with non-toxigenic A. novoparasiticus strains are likely to be more successful than those using non-toxigenic A. flavus strains. Further studies on the association between A. novoparasiticus and Pseudococcus sacchari might shed light on the distribution (and aflatoxin contamination) of this species in sugarcane. Additionally, the interaction between A. novoparasiticus, Pseudococcus sacchari, and sugarcane crop under different scenarios of climate change will be critical in order to get more insight into the host–pathogen interaction and host resistance and propose appropriate prevention strategies to decrease mycotoxin contamination and crop loss due to A. novoparasiticus attack.

scholarly journals A Novel Niosome-Encapsulated Essential Oil Formulation to Prevent Aspergillus flavus Growth and Aflatoxin Contamination of Maize Grains During Storage

Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 646 ◽  
Author(s):  
García-Díaz ◽  
Patiño ◽  
Vázquez ◽  
Gil-Serna
Keyword(s):  
Aspergillus Flavus ◽  
Fungal Growth ◽  
Storage Conditions ◽  
Aflatoxin Contamination ◽  
Small Scale ◽  
Low Concentrations ◽  
Oil Formulation ◽  
Scale Test ◽  
Encapsulation Method

Aflatoxin (AF) contamination of maize is a major concern for food safety. The use of chemical fungicides is controversial, and it is necessary to develop new effective methods to control Aspergillus flavus growth and, therefore, to avoid the presence of AFs in grains. In this work, we tested in vitro the effect of six essential oils (EOs) extracted from aromatic plants. We selected those from Satureja montana and Origanum virens because they show high levels of antifungal and antitoxigenic activity at low concentrations against A. flavus. EOs are highly volatile compounds and we have developed a new niosome-based encapsulation method to extend their shelf life and activity. These new formulations have been successfully applied to reduce fungal growth and AF accumulation in maize grains in a small-scale test, as well as placing the maize into polypropylene woven bags to simulate common storage conditions. In this latter case, the antifungal properties lasted up to 75 days after the first application.

Modelling the colonisation of maize by toxigenic and non-toxigenic Aspergillus flavus strains: implications for biological control

2008 ◽  
Vol 1 (3) ◽  
pp. 333-340 ◽  
Author(s):  
H. Abbas ◽  
R. Zablotowicz ◽  
H. Bruns
Keyword(s):  
Biological Control ◽  
Aspergillus Flavus ◽  
Growth Parameters ◽  
Biological Control Agent ◽  
Cyclopiazonic Acid ◽  
Aflatoxin Contamination ◽  
Tween 20 ◽  
Lag Phase ◽  
Gompertz Equation ◽  
Aflatoxin Accumulation

To successfully exploit biological control it is desirable to understand how the introduced agent colonises the host and interferes with establishment of the pest. This study assessed field colonisation of maize by Aspergillus flavus strains as biological control agents to reduce aflatoxin contamination. Maize (corn, Zea mays L.) ears were inoculated with A. flavus using a pin-bar technique in 2004 and 2005. Non-aflatoxigenic strains K49 (NRRL 30797) & CT3 (NRRL 30798) and toxigenic F3W4 (NRRL 30798) were compared against a carrier control (0.2% aqueous Tween 20). Ten ears were sampled over 12 to 20 days, visually assessed, and curves fit to a three compartment Gompertz equation or other best appropriate regressions. Aflatoxin was determined by HPLC and cyclopiazonic acid (CPA) by LC/MS. The Gompertz model describes growth parameters, e.g. growth constant, lag phase and maximum colonisation characterised patterns of maize colonisation for most inoculated treatments. Aflatoxin accumulation in maize inoculated with F3W4 was about 35,000 ng/g in 2004 and 2005, with kinetics of aflatoxin accumulation in 2005 well described by the Gompertz equation. Less than 200 ng/g was observed in maize inoculated with strains CT3 & K49 and accumulation was described by a linear or logistic model. Maize inoculated with strains CT3 and F3W4 accumulated a maximum of 220 and 169 µg/kg CPA, respectively, compared to 22 and 0.2 µg/kg in the control and K49 inoculated, respectively. This technique can be used to elucidate colonisation potential of non-toxigenic A. flavus in maize in relation to biological control of aflatoxin. The greatest reduction of aflatoxin and CPA in maize inoculated with strain K49 and Gompertz parameters on colonisation indicates its superiority to CT3 as a biological control agent. The dynamics of maize colonisation by A. flavus strains and subsequent mycotoxin accumulation generated by using the pin-bar technique has implications for characterising the competence of biocontrol strains for reducing aflatoxin contamination.

Evaluation of resistance to aflatoxin contamination in kernels of maize genotypes using a GFP-expressing Aspergillus flavus strain

2013 ◽  
Vol 6 (2) ◽  
pp. 151-158 ◽  
Author(s):  
K. Rajasekaran ◽  
C.M. Sickler ◽  
R.L. Brown ◽  
J.W. Cary ◽  
D. Bhatnagar
Keyword(s):  
Fungal Infection ◽  
Aspergillus Flavus ◽  
Fluorescent Protein ◽  
Aflatoxin Contamination ◽  
Clear Correlation ◽  
Aleurone Layer ◽  
Screening Assay ◽  
Maize Germplasm ◽  
Antifungal Proteins ◽  
Green Fluorescent

Resistance or susceptibility of maize inbreds to infection by Aspergillus flavus was evaluated by the kernel screening assay. A green fluorescent protein-expressing strain of A. flavus was used to measure fungal spread and aflatoxin levels in real-time following fungal infection of kernels. Among the four inbreds tested, MI82 showed the most resistance and Ga209 the least. TZAR101 was also resistant to fungal infection, whereas Va35 was susceptible to fungal infection. However, Va35 produced lower aflatoxin levels compared to the susceptible line Ga209. Fluorescence microscopy indicated that the site of entry of the fungus into the kernel was consistently through the pedicel. Entry through the pericarp was never observed in undamaged kernels. In view of these results, incorporation or overexpression of antifungal proteins should be targeted to the pedicel and basal endosperm region in developing kernels. Once the fungus has entered through the pedicel, it spreads quickly through the open spaces between the pericarp and the aleurone layer, ultimately colonising the endosperm and scutellum and, finally, the embryo. A clear correlation was established between fungal fluorescence and aflatoxin levels. This method provides a quick, reliable means of evaluating resistance to A. flavus in undamaged kernels and provides breeders with a rapid method to evaluate maize germplasm.

scholarly journals In Vitro Activity of Balanites aegyptiaca and Tamarindus indica Fruit Extracts on Growth and Aflatoxigenicity of Aspergillus flavus and A. parasiticus

2013 ◽  
Vol 2 (4) ◽  
pp. 68 ◽  
Author(s):  
Saifeldin Ahmed El-nagerabi ◽  
Abdulkadir E. Elshafie ◽  
Mohamed R. Elamin
Keyword(s):  
Aspergillus Flavus ◽  
Fungal Growth ◽  
Aflatoxin Contamination ◽  
Tamarindus Indica ◽  
Balanites Aegyptiaca ◽  
Total Aflatoxin ◽  
Animal Products ◽  
Fruit Extracts ◽  
Aflatoxin B

<p>Aflatoxin and especially aflatoxin B<sub>1</sub> (AFB<sub>1</sub>) is a carcinogenic secondary metabolite synthesized by certain <em>Aspergillus </em>species. They contaminate natural and processed agricultural and animal products which render them unfit for consumption. The aim of this study was to evaluate the <em>in vitro</em> effects of <em>Balanites aegyptiaca</em> and <em>Tamarindus indica</em> fruit extracts on the growth and aflatoxin secretion of <em>Aspergillus flavus</em> (SQU21) and <em>A. parasiticus </em>(CBS921.7) strains. The two fruit extracts significantly (<em>P </em>&lt; 0.05) reduced aflatoxin and did not inhibit mycelial dry weights of the two <em>Aspergillus </em>strains. At different concentrations of balanites (2.5-10%), the inhibition of total aflatoxin was 49.9-84.8% for <em>A. flavus</em> (SQU21) and 32.1-84.4% for <em>A. parasiticus</em> (CBS921.7), whereas the inhibition of aflatoxin Bwas 38.2-81.4% and 32.8-80.6% for the two strains. Tamarind fruit extract (2.5-7.5%) caused 28.8-84.2% and 40.7-85.5% reductions in total aflatoxin and 37.1-83.5% and 33.9-85.9% in aflatoxin B for the two strains, respectively. None of these extracts inhibited the fungal growth or detoxified synthetic aflatoxin B<sub>1</sub>. We have concluded that these fruits contain various inhibitors to aflatoxin biosynthesis and secretion. Therefore, they can be used in combination as safe green biopreservatives to combat aflatoxin contamination of food.</p>

scholarly journals Streptomyces roseolus, A Promising Biocontrol Agent Against Aspergillus flavus, the Main Aflatoxin B1 Producer

Toxins ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 442 ◽  
Author(s):  
Isaura Caceres ◽  
Selma Snini ◽  
Olivier Puel ◽  
Florence Mathieu
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Biocontrol Agent ◽  
Cyclopiazonic Acid ◽  
Over Expression ◽  
Expression Of Genes ◽  
B1 Gene ◽  
Genes Encoding ◽  
Molecular Mechanism Of Action ◽  
Potential Use

Crop contamination by aflatoxin B1 is a current problem in tropical and subtropical regions. In the future, this contamination risk may be expanded to European countries due to climate change. The development of alternative strategies to prevent mycotoxin contamination that further contribute to the substitution of phytopharmaceutical products are thus needed. For this, a promising method resides in the use of biocontrol agents. Several actinobacteria strains have demonstrated to effectively reduce the aflatoxin B1 concentration. Nevertheless, the molecular mechanism of action by which these biological agents reduce the mycotoxin concentration has not been determined. The aim of the present study was to test the potential use of Streptomyces roseolus as a biocontrol agent against aflatoxin B1 contamination. Co-cultures with Aspergillus flavus were conducted, and the molecular fungal response was investigated through analyzing the q-PCR expression of 65 genes encoding relevant fungal functions. Moreover, kojic and cyclopiazonic acid concentrations, as well as morphological fungal changes were also analyzed. The results demonstrated that reduced concentrations of aflatoxin B1 and kojic acid were respectively correlated with the down-regulation of the aflatoxin B1 gene cluster and kojR gene expression. Moreover, a fungal hypersporulated phenotype and a general over-expression of genes involved in fungal development were observed in the co-culture condition.

Wound-Care Resources on the Internet

2006 ◽  
Vol 96 (3) ◽  
pp. 264-268
Author(s):  
Charles R. Fikar ◽  
Brigitte Delinois
Keyword(s):  
Web Sites ◽  
Wound Care ◽  
Medical Practitioner ◽  
Antibiotic Use ◽  
Educational Process ◽  
Reference Source ◽  
Internet Resources ◽  
Hyperbaric Medicine ◽  
Potential Use ◽  
Selection Of

An updated selection of high-quality Internet resources related to wound and ulcer care is presented. Of potential use to the podiatric medical practitioner, educator, resident, and student, some Web sites that cover hyperbaric medicine, antibiotic use, and wound and ulcer prevention are also included. These Web sites have been evaluated on the basis of their potential to enhance the practice of podiatric medicine, in addition to contributing to the educational process. Readers who require a quick reference source to wound and ulcer care may find this report useful. (J Am Podiatr Med Assoc 96(3): 264–268, 2006)

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