Related Experiment Videos
DNA probe for strain typing of Cryptococcus neoformans
1Clinical Mycology Section, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892.
Journal of Clinical Microbiology
|November 1, 1992
Summary
A novel 7-kb linear plasmid in Cryptococcus neoformans, with telomere-like ends, generates unique DNA fingerprints. These fingerprints are stable and useful for tracking fungal populations in clinical and experimental settings.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Cryptococcus neoformans is an opportunistic fungal pathogen.
- Accurate strain identification and population analysis are crucial for understanding cryptococcosis.
- Existing methods for C. neoformans typing may have limitations.
Purpose of the Study:
- To characterize a novel linear plasmid in C. neoformans.
- To evaluate the utility of this plasmid for DNA fingerprinting of C. neoformans strains.
- To assess the stability and reproducibility of the generated DNA fingerprints.
Main Methods:
- Isolation and characterization of a 7-kb linear plasmid from a URA5 transformant of C. neoformans.
- Hybridization of the plasmid to contour-clamped homogeneous electric field electrophoresis-separated chromosomes.
- AccI digestion of genomic DNA from 26 C. neoformans strains followed by Southern blot hybridization with the plasmid probe.
- Analysis of DNA fingerprints from clinical isolates, experimental infections, and laboratory-maintained strains.
Main Results:
- The 7-kb plasmid possesses telomere-like sequences, facilitating its linear maintenance.
- Plasmid hybridization generated 21 unique DNA fingerprints across 26 C. neoformans strains.
- DNA fingerprints showed high similarity within serotypes and stability across different culture media and experimental conditions.
- A widely used acapsular clinical isolate (strain 602) exhibited DNA fingerprints consistent with serotype A, not D.
- Isolates from patients with AIDS and from infected mice revealed homogeneous C. neoformans populations at the time of sampling.
Conclusions:
- The 7-kb linear plasmid serves as a reliable marker for Cryptococcus neoformans DNA fingerprinting.
- This method provides stable and reproducible genetic profiles, aiding in strain differentiation and epidemiological studies.
- The findings highlight the potential for using this plasmid-based fingerprinting to analyze C. neoformans populations in diverse settings, including clinical infections.