Quantitation and mapping of aflatoxin B1-induced DNA damage in genomic DNA using aflatoxin B1-8,9-epoxide and microsomal activation systems

Denissenko, Mikhail F.; Cahill, Jeanne M.; Koudriakova, Tatiana; Gerber, Nicholas; Pfeifer, Gerd P.

doi:10.1016/s0027-5107(99)00038-x

Cited by 58 publications

(47 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Firstly, AFB1 (C17H12O6) is activated to AFB1-8,9-oxide and forms adduct primarily at N7 position of guanine and is responsible for its mutagenic and OPEN    ACCESS carcinogenic effects [5,6]. Secondly, aflatoxins especially AFB1, produce reactive oxygen species (ROS) such as superoxide radical anion, hydrogen peroxide and lipid hydroperoxides; though these do not appear to interact with DNA, but they are precursors to the hydroxyl radical.…”

Section: Introductionmentioning

confidence: 99%

In Vitro Inhibition of Growth and Aflatoxin B1 Production of Aspergillus Flavus Strain (ATCC 16872) by Various Medicinal Plant Essential Oils

Deabes¹,

El-Soud²,

El-Kassem³

2011

Macedonian Journal of Medical Sciences

View full text Add to dashboard Cite

The hazardous nature of aflatoxins to human and animals necessitate the need for establishment of control measures. The objective of this study was to evaluate the inhibition of growth and aflatoxin production of Aspergillus flavus strain (ATCC 16872) by various essential oils in Yeast Extract Sucrose (YES) growth media at 25°C. Essential oils of basil, fennel, coriander, caraway, peppermint and rosemary were tested for their effects on mycelial growth and aflatoxin production. Aflatoxin B1 production was determined by high performance liquid chromatography (HPLC). The findings of this study revealed the antifungal efficacy of the all tested essential oils. The extent of inhibition of fungal growth and aflatoxin production was dependent on the type and concentration of essential oils used. The complete inhibition of Aspergillus flavus growth was observed at 1000 ppm concentrations of essential oils of basil, coriander, caraway and rosemary. While, essential oils of basil and coriander showed marked inhibition of aflatoxin B1 produced by Aspergillus flavus at all concentrations tested 500,750 and 1000 ppm.

show abstract

Section: Introductionmentioning

confidence: 99%

In Vitro Inhibition of Growth and Aflatoxin B1 Production of Aspergillus Flavus Strain (ATCC 16872) by Various Medicinal Plant Essential Oils

Deabes¹,

El-Soud²,

El-Kassem³

2011

Macedonian Journal of Medical Sciences

View full text Add to dashboard Cite

show abstract

“…The G to T mutation is predominantly observed (2,3,(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). Studies of mutational landscapes, by their nature, do not elucidate which specific chemical form of AFB 1 -DNA adduct is responsible for a given mutation (1).…”

mentioning

confidence: 99%

The aflatoxin B ₁ formamidopyrimidine adduct plays a major role in causing the types of mutations observed in human hepatocellular carcinoma

Smela

Hamm

Henderson

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

190

219

View full text Add to dashboard Cite

A G to T mutation has been observed at the third position of codon 249 of the p53 tumor-suppressor gene in over 50% of the hepatocellular carcinoma cases associated with high exposure to aflatoxin B1 (AFB1). Hypotheses have been put forth that AFB1, in concert with hepatitis B virus (HBV), may play a role in the formation of, and͞or the selection for, this mutation. The primary DNA adduct of AFB1 is 8,9-dihydro-8-(N 7 -guanyl)-9-hydroxyaflatoxin B1 (AFB1-N7-Gua), which is converted naturally to two secondary lesions, an apurinic site and an AFB1-formamidopyrimidine (AFB1-FAPY) adduct. AFB1-FAPY is detected at near maximal levels in rat DNA days to weeks after AFB1 exposure, underscoring its high persistence in vivo. The present study reveals two striking properties of this DNA adduct: (i) AFB1-FAPY was found to cause a G to T mutation frequency in Escherichia coli approximately 6 times higher than that of AFB1-N7-Gua, and (ii) one proposed rotamer of AFB1-FAPY is a block to replication, even when the efficient bypass polymerase MucAB is used by the cell. Taken together, these characteristics make the FAPY adduct the prime candidate for both the genotoxicity of aflatoxin, because mammalian cells also have similar bypass mechanisms for combating DNA damage, and the mutagenicity that ultimately may lead to liver cancer. Aflatoxin B 1 (AFB 1 ), one of the most potent known liver carcinogens, is produced by the common soil fungus Aspergillus flavus. Exposure to this toxin is high in regions of the world where certain foods are improperly stored (1). Hepatitis B virus (HBV) is also common in these regions, and epidemiological evidence indicates that there is a synergistic interaction between AFB 1 exposure and HBV infection on the induction of hepatocellular carcinoma (HCC). In over 50% of HCC cases studied in these areas, a characteristic G to T mutation is observed at the third position of codon 249 of the p53 tumorsuppressor gene (2, 3). Whether this specific sequence is an exceptional target for mutations caused by AFB 1 or whether the mutation is selected for once it occurs remains to be determined. However, each of these scenarios shares the fundamental early step involving generation of a G to T mutation.There is substantial evidence that AFB 1 -induced G to T mutations in cellular ras genes may also be a step in transformation of normal cells to malignant cells (4-6). In humans these mutations occur at the first and second positions of codon 12 in the Ha-ras protooncogene (7) and they are in sequence contexts similar, but not identical, to that of codon 249 in p53.Many studies have defined the mutational spectrum produced after exposure of cells to either the epoxide, which is the toxicologically relevant natural metabolite of AFB 1 (8), or to other electrophilic derivatives that serve as models for the epoxide (9). The G to T mutation is predominantly observed (2,3,(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). Studies of mutational landscapes, by their nature, do not elucidate which specific chemical form o...

show abstract

“…Finally, the use of genomic DNA, which includes both nuclear and mitochondrial genomes, allows direct comparison of the degree of damage and/or repair in nDNA versus mtDNA in the same biological sample. In fact, QPCR has been used successfully to quantify damage and repair in nDNA and mtDNA after many types of genotoxicants in a wide variety of cells and tissues [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”

Section: Advantages Of the Assaymentioning

confidence: 99%

Quantitative PCR-Based Measurement of Nuclear and Mitochondrial DNA Damage and Repair in Mammalian Cells

Santos¹,

Meyer²,

Mandavilli³

et al.

Methods in Molecular Biology

274

373

View full text Add to dashboard Cite

In this chapter, we describe a gene-specific quantitative PCR (QPCR)-based assay for the measurement of DNA damage, using amplification of long DNA targets. This assay has been used extensively to measure the integrity of both nuclear and mitochondrial genomes exposed to different genotoxins and has proven to be particularly valuable in identifying reactive oxygen species-mediated mitochondrial DNA damage. QPCR can be used to quantify both the formation of DNA damage as well as the kinetics of damage removal. One of the main strengths of the assay is that it permits monitoring the integrity of mtDNA directly from total cellular DNA without the need for isolating mitochondria or a separate step of mitochondrial DNA purification. Here we discuss advantages and limitations of using QPCR to assay DNA damage in mammalian cells. In addition, we give a detailed protocol of the QPCR assay that helps facilitate its successful deployment in any molecular biology laboratory.

show abstract

Quantitation and mapping of aflatoxin B1-induced DNA damage in genomic DNA using aflatoxin B1-8,9-epoxide and microsomal activation systems

Cited by 58 publications

References 27 publications

<i>In Vitro</i> Inhibition of Growth and Aflatoxin B1 Production of <i>Aspergillus Flavus</i> Strain (ATCC 16872) by Various Medicinal Plant Essential Oils

<i>In Vitro</i> Inhibition of Growth and Aflatoxin B1 Production of <i>Aspergillus Flavus</i> Strain (ATCC 16872) by Various Medicinal Plant Essential Oils

The aflatoxin B ₁ formamidopyrimidine adduct plays a major role in causing the types of mutations observed in human hepatocellular carcinoma

Quantitative PCR-Based Measurement of Nuclear and Mitochondrial DNA Damage and Repair in Mammalian Cells

Contact Info

Product

Resources

About

Quantitation and mapping of aflatoxin B1-induced DNA damage in genomic DNA using aflatoxin B1-8,9-epoxide and microsomal activation systems

Cited by 58 publications

References 27 publications

<i>In Vitro</i> Inhibition of Growth and Aflatoxin B1 Production of <i>Aspergillus Flavus</i> Strain (ATCC 16872) by Various Medicinal Plant Essential Oils

<i>In Vitro</i> Inhibition of Growth and Aflatoxin B1 Production of <i>Aspergillus Flavus</i> Strain (ATCC 16872) by Various Medicinal Plant Essential Oils

The aflatoxin B 1 formamidopyrimidine adduct plays a major role in causing the types of mutations observed in human hepatocellular carcinoma

Quantitative PCR-Based Measurement of Nuclear and Mitochondrial DNA Damage and Repair in Mammalian Cells

Contact Info

Product

Resources

About

The aflatoxin B ₁ formamidopyrimidine adduct plays a major role in causing the types of mutations observed in human hepatocellular carcinoma