Corporate Banner
Satellite Banner
Chromatography
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Chemical Probe Finds Fungal Organism Function

Published: Wednesday, January 16, 2013
Last Updated: Wednesday, January 16, 2013
Bookmark and Share
Activity-based protein profiling suggests how fungus becomes pathogenic.

Two unique chemical probes designed at Pacific Northwest National Laboratory are helping scientists find how a pathogenic organism responsible for a severe lung infection thrives in human serum. These probes use multiplexed activity-based protein profiling (ABPP), which revealed significant changes in Aspergillus fumigatus metabolism and stress response when placed in culture with human serum over time.

Why It Matters. A. fumigatus spores are ubiquitous in the atmosphere, and everybody inhales an estimated several hundred spores each day. But for people whose immune response is compromised from taking immunosuppressive drugs, by irradiation or malnutrition, or by diseases such as cancer or AIDS, this opportunistic pathogen is responsible for pulmonary invasive aspergillosis (IA). Patients with IA are usually critically ill, and the disease is difficult to cure.

The PNNL team hypothesized that A. fumigatus uses human serum, the clear fluid that remains after blood is allowed to clot, as a nutrient and that enzyme activity within the serum impacts the organism's metabolism, nutrient sensing, and scavenging response within an immunocompromised host environment. They simultaneously used two novel activity-based chemical probes they designed and constructed to target the reactivity of A. fumigatus during growth. The team found that probe-protein reactivity changes in the presence or absence of human serum.

The information provides valuable insight into how A. fumigatus survives in a host environment on a fundamental level. During the course of IA, the fungus' filamentous structure breaches host tissue and interacts with serum, where it readily grows because of its unique ability to extract iron from human transferrin in an iron-limited environment. Furthermore, A. fumigatus can use serum proteins as building blocks for growth, but the full effect of serum on its cellular processes and its relevance to disease are not fully understood.

"We are demonstrating that we can compare two systems or one organism under multiple conditions to tease out more information about protein regulation," said Dr. Susan Wiedner, a PNNL Linus Pauling Distinguished Postdoctoral Fellow, and lead author of the paper published in The Journal of Biological Chemistry.

The scientists wanted to determine which proteins interact with a small-molecule activity-based probe. "We found that under two different growth conditions, the number and identity of proteins that interact with the probes change drastically," said Wiedner. "We could measure the abundance of probe-labeled proteins by liquid chromatography-mass spectrometry (LC-MS) -based proteomics and see profiles of labeled proteins based on growth condition."

Methods: Various approaches to LC-MS-based proteomics have emerged. In a typical global analysis, thousands of proteins are measured from a complex proteome. However, by using ABPP, scientists can target a subset of a few hundred proteins from the complex proteome.

"ABPP is a more directed approach than using global proteomics," said Wiedner. "We can look at the difference of probe-labeled protein abundances among various systems and conditions. This then tells us more about the system's biology, such as the differences between probe-reactivity of metabolic proteins. Some fungal proteins interact more with the probe in the presence of human serum, which tells us something about what metabolism might be doing under those conditions." A direct comparison of a global analysis and an ABPP analysis showed differences in measured proteins detected by ABPP that were not detected by global analysis.

In turn, this can lead to more in-depth studies such as generating gene knock-out mutants and performing enzymatic assays, all of which could be used to develop effective treatments and detection of IA.

Over the last two decades, ABPP development has been a growing but still-small field. PNNL has one of the groups working on this, led by PNNL chemist Dr. Aaron Wright, senior author on this paper.

What’s next: Currently, PNNL scientists are developing ABPP probes and supporting bioinformatics capabilities to measure cellulose degradation in microbial communities. ABPP can be useful for a variety of things including target validation of drug candidates and protein inhibitor discovery.

Said Wright, "Probes can compete with known drugs for protein-binding sites, which results in drug target and drug off-target validation. Some probes are broad, like those used in this study. But some can be very selective for an enzyme class. We can design the probe based on the enzyme class being targeted. We used a multiplexed approach here, where two probes were used simultaneously to target more than one type of protein. Previous studies only use one ABP at a time for proteome analysis."


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 3,000+ scientific posters on ePosters
  • More than 4,400+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.


Scientific News
Grant to Fund Million Peaks Project
The European Research Council (ERC) has awarded a prestigious Advanced Grant to Prof. Peter Schoenmakers, Prof. Albert Polman and Prof. Huib Bakker, all three of whom work at the University of Amsterdam (UvA).
Altered Metabolism of Four Compounds Drives Glioblastoma Growth
Findings suggest new ways to treat the malignancy, slow its progression and reveal its extent more precisely.
Why Bearcats Smell Like Buttered Popcorn
Researchers pinpoint chemical compound that gives rare animal its popcorn-like scent.
Human Gut Microbiome Evolution
Westerners have a less-diverse gut microbiome compared to hunter-gatherers, but how and why these microbe collections diverged has largely remained a mystery.
Potential Diagnostic for Dengue Fever
Scientists from Colorado State University have explored the use of small molecules in patient serum for diagnosis of dengue fever and potentially predicting progression to the severe disease.
Non-Destructive Sensing of Fish Freshness
Is there any reliable way to know whether frozen fish is fresh or not?
‘Smelling’ Prostate Cancer
A research team from the University of Liverpool and the University of the West of England (UWE Bristol) has reached an important milestone towards creating a urine diagnostic test for prostate cancer that could mean that invasive diagnostic procedures that men currently undergo eventually become a thing of the past.
Charting Kidney Cancer Metabolism
Changes in cell metabolism are increasingly recognized as an important way tumors develop and progress, yet these changes are hard to measure and interpret. A new tool designed by MSK scientists allows users to identify metabolic changes in kidney cancer tumors that may one day be targets for therapy.
Portable Kit Can Recover Traces of Chemical Evidence
A chemist at the National Institute of Standards and Technology (NIST) has developed a portable version of his method for recovering trace chemicals such as environmental pollutants and forensic evidence including secret graves and arson fire debris.
Diagnosis of Two Rare Childhood Diseases Improved
For the first time, researchers have developed tests that could improve the diagnosis of two rare childhood diseases known as congenital disorders of glycosylation (CDGs) and metachromatic leukodystrophy, and that could even lead to new treatments for CDGs.
SELECTBIO

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
3,000+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,400+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!