Handbook Part 2 - International Mycological Association

S46IS3 - 0998
Comparative genomic analysis of hypoxic stress response in Aspergillus fumigatus and Aspergillus
nidulans
Kap-Hoon Han 1, Anthony Borneman 2,
1 South Korea, 2 Yale University, CT, United States
Aspergillus fumigatus is known as the primary causative agent of aspergillosis, which is an opportunistic fungal disease
mainly localized in the respiratory system of human. Although the patients suffered from the invasive aspergilosis as
well as the allergic diseases are getting increased, molecular mechanism of A. fumigatus infection has not been well
elucidated yet. Currently, A. fumigatus has no known sexual development process, while Aspergillus nidulans, which is
a very close relative of A. fumigatus, undergo complete sexual development process. Furthermore, in A. nidulans,
hypoxic condition is the one of most important environmental factor of which the fungus preferentially generate
fruiting bodies. The hypoxic condition is also important to A. fumigatus because of the environment of host cell is
usually maintained as hypoxic condition. To study relationship between hypoxic stress condition and fungal virulence,
comparative DNA microarray experiment was performed using A. fumigatus and A. nidulans microarray chips which
were provided by pathogenic fungi genome resource center (PFGRC). As a result, we identified 4,332 reliable genes
and, among them, isolated 362 hypoxic condition specific up- or down-regulated genes in A. fumigatus genome.
Northern analysis was performed for validating the microarray analysis. Comparison between A. nidulans gene set
provided information of shared and distinct pathway of hypoxic stress response and sexual development process.
Duplicated analysis using A. fumigatus microarray ver. 2 chipset and relation of hypoxic stress and sexual development
pathway will also be discussed. This work was supported by grant from KOSEF (R1-2006-000-11204-0) and KRF (KRF-2005-
070-C00123).
S46PS1 - 0668
Identification of novel small molecule compounds that differentially inhibit the yeast form of Penicillium
marneffei
R.Y. Kao, S.W. Lee, J.C.S. Madar, K.Y. Yuen
1 Department of Microbiology and Centre of Infection & Immunity, The University of Hong Kong, Hong Kong, China,
2 Department of Computing Science, Capilano College, North Vancouver, British Columbia, Canada
The emergence of Penicillium marneffei as a significant fungal pathogen particularly among human
immunodeficiency virus (HIV) infected individuals living in Southeast Asia and southern part of China (including Hong
Kong) poses a clear and immediate threat to these already heavily burdened regional public health systems. P.
marneffei is the only thermally dimorphic species in its genus. It has been well speculated that thermal dimorphism of
fungal pathogens is closely linked to their virulence. Our recent acquisition of a validated high quality diverse
chemical library (50,240 small molecules with drug-like properties) and automated robotic platforms for highthroughput
screening (HTS) enabled us to tackle virulence and dimorphism in P. marneffei using chemical geneticsthe
use of high-throughput screening (HTS) technologies to identify biologically active small molecules that will
interfere with particular cellular processes/biological pathways/gene products in an organism.
Construction of an EGFP-expressing P. marneffei strain: Yeast cells of P. marneffei were grown at 37 oC to 2x108 CFU/ml
in RPMI 1640 media. Cells were harvested and transformed with EGFP gene. P. marneffei transformants with plasmid
gGFP integrated stably into the genome were selected on hygromycin B containing media.
Small-molecule compounds interfering with the growth of P. marneffei in vitro: EGFP-expressing strain of P. marneffei
(104 cells/well) were cultured in RPMI 1640 at 37 oC in 5% CO2 in 384 well microtitre plates. 50,240 small-molecule
compounds from the chemical library were transferred to each assay well using fully automated robotic platforms. The
growth of the P. marneffei was monitored by GFP fluorescence
We have identified small molecule compounds that would specifically inhibit the 37 ºC growing yeast form of P.
marneffei but not the 25 ºC growing mould form. The whole set of screening data will be presented and the
compounds that selectively inhibited the yeast form at low micromolar concentrations without apparent inhibitory
activity against mould form will be highlighted.
We are exploring novel strategies that can be employed to dissect complicated biological pathways involved in
fungal pathogenesis. Compounds that interfere with specific growth phases of the fungus were successfully identified.
The establishment of the first model of forward chemical genetics in P. marneffei will open new possibilities for the
investigation of the pathogenesis of other model pathogenic fungi such as Aspergillus fumigatus and Cadida albican.
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