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