Work

Strain-Dependent Variation in 18S Ribosomal DNA Copy Numbers in Aspergillus fumigatus

Year: 2009

Type: article

Abstract: Enumerating Aspergillus fumigatus CFU can be challenging since CFU determination by plate count can be difficult. CFU determination by quantitative real-time PCR (qPCR), however, is becoming increasingly common and usually relies on detecting one of the subunits of the multicopy rRNA genes. This study was undertaken to determine if ribosomal DNA (rDNA) copy number was constant or variable among different A. fumigatus isolates. FKS1 was used as a single-copy control gene and was validated against single-copy (pyrG and ARG4) and multicopy (arsC) controls. The copy numbers of the 18S rDNA subunit were then determined for a variety of isolates and were found to vary with the strain, from 38 to 91 copies per genome. Investigation of the stability of the 18S rDNA copy number after exposure to a number of different environmental and growth conditions revealed that the copy number was stable, varying less than one copy across all conditions, including in isolates recovered from an animal model. These results suggest that while the ribosomal genes are excellent targets for enumeration by qPCR, the copy number should be determined prior to using them as targets for quantitative analysis.

Source: Journal of Clinical Microbiology

DOI: 10.1128/jcm.02073-08

Authors: M. L. Herrera, A. C. Vallor, J. A. Gelfond, T. F. Patterson, B. L. Wickes

Institution: The University of Texas at San Antonio Health Science Center

Language: English

Topic: Antifungal resistance and susceptibility

Subfield: Infectious Diseases

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: green

Funders: National Institutes of Health, Centers for Disease Control and Prevention, National Institute of Allergy and Infectious Diseases, Congressionally Directed Medical Research Programs