Expression of genes of the aflatoxin biosynthetic pathway in Aspergillus flavus isolates from keratitis

George Leema, Duen Suey Chou, Christadoss A. Nelson Jesudasan, Pitchairaj Geraldine, Philip A. Thomas

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Purpose: To document transcriptional activation (expression) of key aflatoxin biosynthetic pathway genes in corneal isolates of Aspergillus flavus. Methods: The expression of certain regulatory (aflatoxin regulatory [aflR] and aflatoxin J [aflJ]) and structural (polyketide synthase acetate [pksA] and norsolonic acid-1 [nor-1]) genes in four corneal A. flavus isolates was evaluated by reverse transcription PCR. The aflatoxin-producing potential of each strain was determined by thin-layer chromatography and quantified by spectrophotometry. Four environmental isolates were used for comparison. The mean expression levels of these genes were compared in the corneal and environmental A. flavus isolates. In addition, the mean expression levels were also correlated with the aflatoxin production levels. Results: All isolates expressed aflJ, nor-1, and pksA, while all but one expressed aflR. Overall, significantly higher mean expression levels occurred in aflatoxigenic than in non-aflatoxigenic corneal isolates. A significant positive correlation was noted between the mean expression level of aflR and the quantum of aflatoxin production by the corneal isolates. Essentially similar patterns of expression of these genes were noted in four environmental A. flavus isolates used for comparison. Conclusions: For the first time, isolates of A. flavus from human keratitis patients have been shown to express regulatory and structural aflatoxin biosynthetic pathway genes. Further studies are needed to clarify the precise influence of the corneal microenvironment on expression of these genes and aflatoxin production by A. flavus infecting the cornea.

Original languageEnglish
Pages (from-to)2889-2897
Number of pages9
JournalMolecular Vision
Volume17
Publication statusPublished - 2011

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Aspergillus flavus
Aflatoxins
Keratitis
Biosynthetic Pathways
Gene Expression
Polyketide Synthases
Acetates
Genes
Acids
Spectrophotometry
Thin Layer Chromatography
Cornea
Transcriptional Activation
Reverse Transcription

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Leema, G., Chou, D. S., Nelson Jesudasan, C. A., Geraldine, P., & Thomas, P. A. (2011). Expression of genes of the aflatoxin biosynthetic pathway in Aspergillus flavus isolates from keratitis. Molecular Vision, 17, 2889-2897.

Expression of genes of the aflatoxin biosynthetic pathway in Aspergillus flavus isolates from keratitis. / Leema, George; Chou, Duen Suey; Nelson Jesudasan, Christadoss A.; Geraldine, Pitchairaj; Thomas, Philip A.

In: Molecular Vision, Vol. 17, 2011, p. 2889-2897.

Research output: Contribution to journalArticle

Leema, G, Chou, DS, Nelson Jesudasan, CA, Geraldine, P & Thomas, PA 2011, 'Expression of genes of the aflatoxin biosynthetic pathway in Aspergillus flavus isolates from keratitis', Molecular Vision, vol. 17, pp. 2889-2897.
Leema, George ; Chou, Duen Suey ; Nelson Jesudasan, Christadoss A. ; Geraldine, Pitchairaj ; Thomas, Philip A. / Expression of genes of the aflatoxin biosynthetic pathway in Aspergillus flavus isolates from keratitis. In: Molecular Vision. 2011 ; Vol. 17. pp. 2889-2897.
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