Impact/Purpose:

1. Develop a method, based on microarray analysis, to identify potential waterborne pathogens using the mRNA response in mammalian cells exposed to these pathogens.

2. Develop computational toxicology approach to understanding hemolysins as virulence factors and for predicting virulence of untested microorganisms.

Description:

Computational toxicology is a rapid approach to screening for toxic effects and looking for common outcomes that can result in predictive models. The long term project will result in the development of a database of mRNA responses to known water-borne pathogens. An understanding of the mRNA responses to pathogens in human host tissue may allow the identification of previously uncharacterized bacteria that have the potential to be human pathogens. If successful, this research might also provide the scientific basis for real-time, pathogen specific technology that can be used for monitoring water systems, both at water treatment plants and in the distribution system itself.

Hemolysins are proteins produced by many pathogenic microorganisms that are often important virulence factors. In this phase of the project, hemolysins will be screened to determine their response patterns in human tissue culture cells. We expect to find that various hemolysins will cause patterns of mRNA response which will cluster into various common groups. These patterns will then be used to predict the effects of untested microorganisms. These predictions will provide insights into nature of the virulence mechanisms, and more importantly, estimate the potential health implications of these untested microorganisms without extensive animal studies.

Record Details:

Record Type:PROJECT

Start Date:01/01/2003

Projected Completion Date:09/01/2007

OMB Category:Other

Record ID: 18345

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Project Information:

Progress :This is one of five tasks in MCEARD for understanding and characterizing the use of virulence factors to predict the hazard that microorganisms may have for humans. Experimental activity has begun on this project. In the initial studies, Aeromonas isolates are being tested in both young immunocompromised mice and also in mice pups for signs of infection. Presently some isolates have been identified that are virulent and one that is non-virulent, which will allow the development of a standard protocol for determining virulence of Aeromonas in these mice. Primary cell lines have been established from mouse intestinal cells. Virulent A. hydrophila strains have been exposed to both neonatal mice and the intestinal cell line. The mRNA response patterns from these experiments have been collected and analyzed with the in-house microarray technology. Data analysis has been accomplished through an IAG with the Department of Energy. Data taken to date indicate that virulence-associated genes are in fact up-regulated in host cells and a subset of these genes were observed to be affected in both the neonatal cells and the intestinal cell line. A manuscript describing these results has been written and is under review internally.





Relevance :The methodology proposed here, using microarray technology, offers the promise of predicting the virulence of a bacteria/virus/protozoan parasite isolated from water. This information will be needed to fully characterize pathogens on CCLs and the successful development of this technology might lead to the identification of previously unidentified microbial pathogens. This approach to virulence determination also offers promise as a substitute for animal models. The ability to distinguish between virulent and avirulent members of bacterial/protozoan species and viruses would be of great value to the OGWDW, state and local health officials and all other organizations concerned about waterborne disease.

Clients :Dr. Paul Berger , OGWDW, Office of Water

Research Component :CCL (MICROBIAL)

Risk Paradigm :EXPOSURE

Project IDs:

ID Code :13335

Project type :OMIS