scholarly journals Using Aflatoxin B1 Regulatory Gene Sequencing to Study Similarity and Difference between Aspergillus flavus Strains, Isolated from Patients with Aspergllosis

2014 ◽  
Vol 6 (6) ◽  
pp. 229-233
Author(s):  
Nemat J. Al-judy
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Regulatory Gene ◽  
Gene Sequencing ◽  
Similarity And Difference

scholarly journals Detection the Ability of Aspergillus flavus Isolated from Wheat Grains for Aflatoxin B1 Production using RT- PCR

2015 ◽  
Vol 9 (2) ◽  
pp. 102-106
Author(s):  
Eman Noaman Ismail
Keyword(s):  
Molecular Weight ◽  
Triticum Aestivum ◽  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Reverse Transcription ◽  
Regulatory Gene ◽  
Rapid Assessment ◽  
Rt Pcr ◽  
Cdna Synthesis ◽  
Wheat Grains

Aspergillus flavus is aflatoxinogenic and potential aflatoxins producers in agriculturalcommodities. The present study was conducted determine the ability of eleven strains of A. flavusisolated from Iraqi wheat grains Triticum aestivum. The isolates have been detected by molecularmethods using Reverse Transcriptase RTPCR. In this study, RNA was extracted from A. flavus,cDNA synthesis and rapid assessment of eleven isolates of A. flavus was accomplished usingprimer pair for the aflatoxin regulatory gene aflR Reverse transcription-Polymerase chainreaction (RT–PCR).Positive amplification was achieved for all the isolates with a molecularweight 798 to aflR1 and 400bp to aflR2. Also the result of the amplification showed there are nodifferences with the two molecular weight between the 11 isolated strains of A. flavus in theiraflatoxin B1 production, but the first strain differed in their banding florescence as comparedwith others strains this reflect the genetic differences in aflatoxin B1 production between them.

scholarly journals PCR Detection of Aspergillus flavus Isolates for Aflatoxin B1 producer

2013 ◽  
Vol 7 (3) ◽  
pp. 81-89
Author(s):  
Abdulkareem Jasim Hashim ◽  
Abdulkareem A. Al-Kazaz ◽  
Hadeel Waleed Abdulmalek
Keyword(s):  
Polymerase Chain Reaction ◽  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Pure Culture ◽  
Regulatory Gene ◽  
Rapid Assessment ◽  
Chain Reaction ◽  
Good Producer ◽  
Culture Systems ◽  
Polymerase Chain

The ability of five Aspergillus flavus that produce Aflatoxin B1 have been detected using coconut medium as substrate. Chromatographical analysis by TLC and HPLC revealed that, three out of five isolates were a good producer for the Aflatoxin B1. In this study, rapid assessment of five isolates of A. flavus was accomplished using an indigenously designed primer pair for the Aflatoxin regulatory gene aflR in polymerase chain reaction (PCR). Specificity was assayed in pure culture systems using DNA extracted from five different A. flavus isolates as PCR template. Positive amplification was achieved only with DNA from A. flavus that produce Aflatoxin B1.

scholarly journals Role of Oxidative Stress in Sclerotial Differentiation and Aflatoxin B1 Biosynthesis in Aspergillus flavus

2014 ◽  
Vol 80 (18) ◽  
pp. 5561-5571 ◽  
Author(s):  
Konstantinos Grintzalis ◽  
Spyros I. Vernardis ◽  
Maria I. Klapa ◽  
Christos D. Georgiou
Keyword(s):  
Oxidative Stress ◽  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Regulatory Gene ◽  
Lipid Hydroperoxide ◽  
Stress Factors ◽  
Irreversible Inhibitor ◽  
Content Type ◽  
Stress Levels ◽  
Sclerotial Differentiation

ABSTRACTWe show here that oxidative stress is involved in both sclerotial differentiation (SD) and aflatoxin B1 biosynthesis inAspergillus flavus. Specifically, we observed that (i) oxidative stress regulates SD, as implied by its inhibition by antioxidant modulators of reactive oxygen species and thiol redox state, and that (ii) aflatoxin B1 biosynthesis and SD are comodulated by oxidative stress. However, aflatoxin B1 biosynthesis is inhibited by lower stress levels compared to SD, as shown by comparison to undifferentiatedA. flavus. These same oxidative stress levels also characterize a mutantA. flavusstrain, lacking the global regulatory geneveA. This mutant is unable to produce sclerotia and aflatoxin B1. (iii) Further, we show that hydrogen peroxide is the main modulator ofA. flavusSD, as shown by its inhibition by both an irreversible inhibitor of catalase activity and a mimetic of superoxide dismutase activity. On the other hand, aflatoxin B1 biosynthesis is controlled by a wider array of oxidative stress factors, such as lipid hydroperoxide, superoxide, and hydroxyl and thiyl radicals.

scholarly journals Mimosa tenuiflora Aqueous Extract: Role of Condensed Tannins in Anti-Aflatoxin B1 Activity in Aspergillus flavus

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 391
Author(s):  
Christopher Hernandez ◽  
Laura Cadenillas ◽  
Anwar El Maghubi ◽  
Isaura Caceres ◽  
Vanessa Durrieu ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Aqueous Extract ◽  
Aflatoxin B1 ◽  
Condensed Tannins ◽  
Fungal Growth ◽  
Oxidation Reactions ◽  
Expression Of Genes ◽  
Dependent Inhibition ◽  
Interesting Candidate ◽  
Mimosa Tenuiflora

Aflatoxin B1 (AFB1) is a potent carcinogenic mycotoxin that contaminates numerous crops pre- and post-harvest. To protect foods and feeds from such toxins without resorting to pesticides, the use of plant extracts has been increasingly studied. The most interesting candidate plants are those with strong antioxidative activity because oxidation reactions may interfere with AFB1 production. The present study investigates how an aqueous extract of Mimosa tenuiflora bark affects both the growth of Aspergillus flavus and AFB1 production. The results reveal a dose-dependent inhibition of toxin synthesis with no impact on fungal growth. AFB1 inhibition is related to a down-modulation of the cluster genes of the biosynthetic pathway and especially to the two internal regulators aflR and aflS. Its strong anti-oxidative activity also allows the aqueous extract to modulate the expression of genes involved in fungal oxidative-stress response, such as msnA, mtfA, atfA, or sod1. Finally, a bio-guided fractionation of the aqueous extract demonstrates that condensed tannins play a major role in the anti-aflatoxin activity of Mimosa tenuiflora bark.

scholarly journals Impacts of Climate Change Interacting Abiotic Factors on Growth, aflD and aflR Gene Expression and Aflatoxin B1 Production by Aspergillus flavus Strains In Vitro and on Pistachio Nuts

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 385
Author(s):  
Alaa Baazeem ◽  
Alicia Rodriguez ◽  
Angel Medina ◽  
Naresh Magan
Keyword(s):  
Climate Change ◽  
Gene Expression ◽  
Water Stress ◽  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Abiotic Factors ◽  
Pistachio Nuts ◽  
Significant Difference ◽  
Spoilage Fungi

Pistachio nuts are an important economic tree nut crop which is used directly or processed for many food-related activities. They can become colonized by mycotoxigenic spoilage fungi, especially Aspergillus flavus, mainly resulting in contamination with aflatoxins (AFs), especially aflatoxin B1 (AFB1). The prevailing climate in which these crops are grown changes as temperature and atmospheric CO2 levels increase, and episodes of extreme wet/dry cycles occur due to human industrial activity. The objectives of this study were to evaluate the effect of interacting Climate Change (CC)-related abiotic factors of temperature (35 vs. 37 °C), CO2 (400 vs. 1000 ppm), and water stress (0.98–0.93 water activity, aw) on (a) growth (b) aflD and aflR biosynthetic gene expression and (c) AFB1 production by two strains A. flavus (AB3, AB10) in vitro on milled pistachio-based media and when colonizing layers of shelled raw pistachio nuts. The A. flavus strains were resilient in terms of growth on pistachio-based media and the colonisation of pistachio nuts with no significant difference when exposed to the interacting three-way climate-related abiotic factors. However, in vitro studies showed that AFB1 production was significantly stimulated (p < 0.05), especially when exposed to 1000 ppm CO2 at 0.98–0.95 aw and 35 °C, and sometimes in the 37 °C treatment group at 0.98 aw. The relative expression of the structural aflD gene involved in AFB1 biosynthesis was decreased or only slightly increased, relative to the control conditions at elevated CO, regardless of the aw level examined. For the regulatory aflR gene expression, there was a significant (p < 0.05) increase in 1000 ppm CO2 and 37 °C for both strains, especially at 0.95 aw. The in situ colonization of pistachio nuts resulted in a significant (p < 0.05) stimulation of AFB1 production at 35 °C and 1000 ppm CO2 for both strains, especially at 0.98 aw. At 37 °C, AFB1 production was either decreased, in strain AB3, or remained similar, as in strain AB10, when exposed to 1000 ppm CO2. This suggests that CC factors may have a differential effect, depending on the interacting conditions of temperature, exposure to CO2 and the level of water stress on AFB1 production.

scholarly journals Production of aflatoxins and aflatoxicols by Aspergillus flavus and Aspergillus parasiticus and metabolism of aflatoxin B1 by aflatoxin-non-producing Aspergillus flavus.

Eisei kagaku ◽  
1991 ◽  
Vol 37 (2) ◽  
pp. 107-116 ◽  
Author(s):  
MITSUO NAKAZATO ◽  
SATOSHI MOROZUMI ◽  
KAZUO SAITO ◽  
KENJI FUJINUMA ◽  
TAICHIRO NISHIMA ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Aspergillus Parasiticus

EVALUATION OF SUSCEPTIBILITY OF PISTACHIO CULTIVARS TO AFLATOXIGENIC ASPERGILLUS FLAVUS AND AFLATOXIN B1 PRODUCTION

2006 ◽  
pp. 655-658 ◽  
Author(s):  
M.M. Moghaddam ◽  
E.M. Goltapeh ◽  
H. Hokmabadi ◽  
M. Haghdel ◽  
A.M. Mortazavi
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin B1

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.

scholarly journals Fullerol C60(OH)24 nanoparticles modulate aflatoxin B1 biosynthesis in Aspergillus flavus

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Tihomir Kovač ◽  
Ivana Borišev ◽  
Biljana Crevar ◽  
Frane Čačić Kenjerić ◽  
Marija Kovač ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin B1
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