scholarly journals Discrimination between aflatoxigenic and non-aflatoxigenic Aspergillus section Flavi strains from Egyptian peanuts using molecular and analytical techniques

2011 ◽  
Vol 4 (1) ◽  
pp. 69-77 ◽  
Author(s):  
A. Abdel-Hadi ◽  
D. Carter ◽  
N. Magan
Keyword(s):  
Expression Profiles ◽  
Regulatory Gene ◽  
Analytical Techniques ◽  
Aflatoxin Production ◽  
Natural Food ◽  
Aspergillus Section Flavi ◽  
Molecular Approaches ◽  
Wide Range ◽  
Aspergillus Section

A wide range of Aspergillus section Flavi strains were isolated from Egyptian peanut samples. Eighteen of these strains were compared with two type strains (Aspergillus flavus SRRC G1907 and Aspergillus parasiticus 2747) for aflatoxin production based on (a) qualitative fluorescence using a coconut cream agar medium (CAM), and (b) aflatoxin production on a conducive Yeast Extract-Sucrose (YES) medium using HPLC. These results were validated by using molecular approaches (the structural genes, aflD (nor-1), aflM (ver-1) and aflP (omt A) and the regulatory gene aflR) to discriminate between aflatoxigenic and non-aflatoxigenic strains of the Aspergillus section Flavi group in vitro and on peanut seeds. Overall, 13/18 strains producing aflatoxins B1 and B2 in the range 1.27-213.35 µg/g medium were identified. In addition, 5 non-aflatoxin producing strains were found. The expression of these four genes was assessed using PCR and RT-PCR. PCR showed that all strains contained the four aflatoxin genes examined, regardless of expression profiles. Our results also showed that aflD expression is a reliable marker to discriminate between aflatoxin and non-aflatoxin producers. Interestingly, when an aflatoxin producing strain and three non-aflatoxigenic strains were subsequently grown on peanuts at 0.95 water activity, two of the non-producers were able to initiate aflatoxin biosynthesis. This suggests that growth of strains on the natural food matrix is important for confirming aflatoxigenic production potential.

Quantitative Detection of Aflatoxin and Species Identification of Aspergillus section Flavi Isolates from Peanuts using Molecular Approaches

2020 ◽  
Author(s):  
I. Lavkor
Keyword(s):  
Sequence Data ◽  
Aflatoxin Production ◽  
Quantitative Detection ◽  
Aflatoxin Biosynthesis ◽  
Chain Reactions ◽  
Polymerase Chain Reactions ◽  
Dna Sequence Data ◽  
Aspergillus Section Flavi ◽  
Molecular Approaches ◽  
Aspergillus Section

Totally, 50 Aspergillus section Flavi were identified isolates having aflatoxin biosynthesis genes on peanut by molecular method and aflatoxin production. Primer pair (IGS-F/R) recognized the aflatoxin biosynthesis gene (aflJ-aflR) targeting the intergenic region (IGS) on DNA was amplified by polymerase chain reactions (PCR). The PCR product were restricted by BglII enzyme within Restriction Fragment Length Polymorphism (RFLP) and obtained from 33 (66%) Aspergillus flavus was cleaved into three band sizes of 362, 210 and 102 bp. However, BglII enzyme generated two band sizes of 363 and 311 bp for 17 (34%) Aspergillus parasiticus. An investigation examined DNA sequence data to characterize these isolates and describe the species. Phylogenetic analysis showed that A. flavus and A. parasiticus have been identified in different groups. All the A. flavus and A. parasiticus isolates produced aflatoxins. The present study provides a new method on molecular characterization of A. section Flavi in Turkey.

scholarly journals The Diverse Roles of the Global Transcriptional Regulator PhoP in the Lifecycle of Yersinia pestis

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1039
Author(s):  
Hana S. Fukuto ◽  
Gloria I. Viboud ◽  
Viveka Vadyvaloo
Keyword(s):  
Yersinia Pestis ◽  
Current Knowledge ◽  
Response Regulator ◽  
Expression Profiles ◽  
Critical Role ◽  
Gene Expression Profiles ◽  
Acanthamoeba Castellanii ◽  
Wide Range

Yersinia pestis, the causative agent of plague, has a complex infectious cycle that alternates between mammalian hosts (rodents and humans) and insect vectors (fleas). Consequently, it must adapt to a wide range of host environments to achieve successful propagation. Y. pestis PhoP is a response regulator of the PhoP/PhoQ two-component signal transduction system that plays a critical role in the pathogen’s adaptation to hostile conditions. PhoP is activated in response to various host-associated stress signals detected by the sensor kinase PhoQ and mediates changes in global gene expression profiles that lead to cellular responses. Y. pestis PhoP is required for resistance to antimicrobial peptides, as well as growth under low Mg2+ and other stress conditions, and controls a number of metabolic pathways, including an alternate carbon catabolism. Loss of phoP function in Y. pestis causes severe defects in survival inside mammalian macrophages and neutrophils in vitro, and a mild attenuation in murine plague models in vivo, suggesting its role in pathogenesis. A Y. pestisphoP mutant also exhibits reduced ability to form biofilm and to block fleas in vivo, indicating that the gene is also important for establishing a transmissible infection in this vector. Additionally, phoP promotes the survival of Y. pestis inside the soil-dwelling amoeba Acanthamoeba castellanii, a potential reservoir while the pathogen is quiescent. In this review, we summarize our current knowledge on the mechanisms of PhoP-mediated gene regulation in Y. pestis and examine the significance of the roles played by the PhoP regulon at each stage of the Y. pestis life cycle.

scholarly journals Aflatoxin Contamination of Dried Insects and Fish in Zambia

2018 ◽  
Vol 81 (9) ◽  
pp. 1508-1518 ◽  
Author(s):  
PAUL W. KACHAPULULA ◽  
JULIET AKELLO ◽  
RANAJIT BANDYOPADHYAY ◽  
PETER J. COTTY
Keyword(s):  
Dietary Protein ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Food Contaminants ◽  
Edible Insect ◽  
Aspergillus Section Flavi ◽  
Regulatory Limits ◽  
Data Gaps ◽  
Dried Fish ◽  
Aspergillus Section

ABSTRACT Dried insects and fish are important sources of income and dietary protein in Zambia. Some aflatoxin-producing fungi are entomopathogenic and also colonize insects and fish after harvest and processing. Aflatoxins are carcinogenic, immune-suppressing mycotoxins that are frequent food contaminants worldwide. Several species within Aspergillus section Flavi have been implicated as causal agents of aflatoxin contamination of crops in Africa. However, aflatoxin producers associated with dried fish and edible insects in Zambia remain unknown, and aflatoxin concentrations in these foods have been inadequately evaluated. The current study sought to address these data gaps to assess potential human vulnerability through the dried fish and edible insect routes of aflatoxin exposure. Caterpillars (n = 97), termites (n = 4), and dried fish (n = 66) sampled in 2016 and 2017 were assayed for aflatoxin by using lateral flow immunochromatography. Average aflatoxin concentrations exceeded regulatory limits for Zambia (10 μg/kg) in the moth Gynanisa maja (11 μg/kg), the moth Gonimbrasia zambesina (Walker) (12 μg/kg), and the termite Macrotermes falciger (Gerstacker) (24 μg/kg). When samples were subjected to simulated poor storage, aflatoxins increased (P < 0.001) to unsafe levels in caterpillars (mean, 4,800 μg/kg) and fish (Oreochromis) (mean, 23 μg/kg). The L strain morphotype of A. flavus was the most common aflatoxin producer on dried fish (88% of Aspergillus section Flavi), termites (68%), and caterpillars (61%), with the exception of Gynanisa maja, for which A. parasiticus was the most common (44%). Dried fish and insects supported growth (mean, 1.3 × 109 CFU/g) and aflatoxin production (mean, 63,620 μg/kg) by previously characterized toxigenic Aspergillus section Flavi species, although the extent of growth and aflatoxigenicity depended on specific fungus-host combinations. The current study shows the need for proper storage and testing of dried insects and fish before consumption as measures to mitigate human exposure to aflatoxins through consumption in Zambia.

Fungal screening and aflatoxin production by Aspergillus section Flavi isolated from pre-harvest maize ears grown in two Argentine regions

2017 ◽  
Vol 92 ◽  
pp. 41-48 ◽  
Author(s):  
Boris X. Camiletti ◽  
Ada K. Torrico ◽  
M. Fernanda Maurino ◽  
Diego Cristos ◽  
Carina Magnoli ◽  
...  
Keyword(s):  
Aflatoxin Production ◽  
Aspergillus Section Flavi ◽  
Aspergillus Section

scholarly journals Identification of Competing Endogenous RNA and Micro-RNA Profiles and Regulatory Networks in 4-Nonylphenol-induced Impairment of Sertoli Cells

2021 ◽  
Vol 12 ◽  
Author(s):  
Wenjie Liu ◽  
Zhaokai Wang ◽  
Xiaopeng Hu
Keyword(s):  
Sertoli Cells ◽  
Cell Function ◽  
Expression Profiles ◽  
Micro Rna ◽  
Male Reproduction ◽  
Sequencing Data ◽  
Reproductive Toxicology ◽  
Network Analyses ◽  
Wide Range

The xenoestrogens nonylphenols (NPs), which are materials used in the plastic polymer industry, are considered endocrine disruptors in a wide range of organisms. Studies have shown that human health problems, such as infertility and reproductive toxicology, are linked with NPs. However, the mechanism by which NPs interfere with male reproduction is not fully elucidated. Here, we found that 4-NP can result in male reproductive impairment and reduce androgen receptor (AR) protein levels in rat sertoli cells in vitro and in vivo. Moreover, we performed RNA sequencing to assess the differential expression of ceRNAs in rat primary sertoli cells treated with 4-NP. Bioinformatics methods, such as Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) database and ceRNA functional network analyses, were used to investigate the sequencing data and gain further understanding of the biological processes. Our analysis revealed a core set of mRNAs (Ar, Atf6 and Cbp), and circRNAs (circ673, circ1377, circ1789, and circPTEN) that were selected and validated by RT-qPCR. In addition, the head-to-tail splicing of circ673, circ1377, circ1789, and circPTEN was identified by Sanger sequencing. These findings provide the first insight into the ceRNA expression profiles of rat sertoli cells and reveal that ceRNAs participate in 4-NP-induced impairment of sertoli cell function, thereby indicating potential therapies for both reproductive toxicology and male infertility.

scholarly journals Occurrence of Aflatoxins in Rice Intended for Infant Flour Production in Ouagadougou, Burkina Faso

2021 ◽  
pp. 55-66
Author(s):  
Hamidou Compaoré ◽  
Serge Samandoulougou ◽  
Clarisse S. Compaoré ◽  
Alima Bambara ◽  
Hissein Ratongué ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
High Performance ◽  
Fluorescence Emission ◽  
Ultra Violet ◽  
Aflatoxin Production ◽  
Chemistry Laboratory ◽  
Aspergillus Section Flavi ◽  
Aflatoxin B2 ◽  
Flour Production ◽  
Aspergillus Section

A total of four samples of rice intended for infant flour production in Ouagadougou were received at the Physico-chemistry laboratory of Food Technology Department (DTA) for quality control. The latter were also tested for Aspergillus section Flavi presence and analyzed for aflatoxins B1, B2, G1 and G2 content using high performance liquid chromatography (HPLC). Among the twenty (20) strains of mold isolated from these samples, three Aspergillus section Flavi were obtained and cultivated in “Aspergillus flavus and parasiticus Agar (AFPA)” to ascertain if they belong to Aspergillus flavus or Aspergillus parasiticus species. The qualitative ability of aflatoxin production was also performed by fluorescence emission under ultra violet light at 365 nm after four days of incubation at 30 °C on Coconut Agar Medium (CAM). Statistical analysis results showed that 75% of samples were contaminated with total aflatoxins (AFs) with contents ranging from 0.54 ± 0.06 to 2.40 ± 0.07 µg/Kg. Aflatoxin B1 (AFB1) and aflatoxin B2 (AFB2) were detected in two contaminated samples. AFB1 had the highest concentration as compared with other aflatoxins. A significant level of contamination (p< 0.0001) was observed in sample R441 compared to other sample types.

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