Project number: 2008-030
Project Status:
Completed
Budget expenditure: $213,043.00
Principal Investigator: Brian Jones
Organisation: Department of Primary Industries and Regional Development (DPIRD) WA
Project start/end date: 30 Jun 2008 - 29 Jun 2011
Contact:
FRDC

Need

In October 2006, unexplained high mortalities of Pinctada maxima oysters were reported. The disease associated with these mortalities has been termed Oyster Oedema Disease (OOD). It is likely that OOD is caused by an infectious agent and it is possible to cross-infect oysters with infected tissue. The disease spread rapidly and there are no known control measures, no knowledge of a causative agent, no understanding of how widespread the disease was, and no way to test for it. This proposal seeks to develop DNA microarray technology to detect abnormal levels of stress response genes in pearl oysters. These genes will be used as markers in new, rapid diagnostic tests for diseased pearl oysters. The requirement for such rapid diagnostic tests for the detection of OOD is well acknowledged. The spread of the disease could have been limited had there been a test available to differentiate sick animals from healthy ones. Such assays also have applications in routine translocation testing and the assessment of general oyster health. Translocation samples are treated as high priority and current methods report results after several days. With rapid tests derived from DNA microarray analysis it may be possible to report results within 24 hours. The attraction of molecular stress-response markers is that their expression levels change dramatically during times of stress. This can act as an indicator of disease susceptibility. A DNA microarray to target such stress markers in P. maxima could
also be used to investigate disease in other shellfish and it will be able to detect effects of other pathogens in addition to those involved in OOD. Our main goal is to use the P. maxima microarray to identify key stress-response genes that can be used to develop a new generation of rapid, inexpensive tests of environmental stress, infection and overall oyster health.

Objectives

1. To construct a cDNA library using healthy, stressed and OOD-affected oysters. We will use oysters exposed to a range of environmental conditions to make sure that a broad array of stress-response genes are represented in the cDNA library. Cloned cDNAs will be analyzed by PCR to confirm that a broad range of different sized cDNA is also included in the library.
2. To design and print DNA microarray slides for the analysis of diseased states in pearl oysters (P. maxima). cDNA clones to print will be based on sequence analysis. cDNA's will be printed onto the slides in duplicate or triplicate to increase the statistical robustness of subsequent analyses.
3. To use the DNA microarray to identify molecular markers that differentiate pearl oysters that are diseased (including OOD-affected oysters) from those that appear to be healthy.
4. To use the DNA microarray to test for markers of adverse health in pearl oysters that appear to be affected by environmental stressors other than OOD. This will be done using archived samples and oysters that do not fit the case definition for OOD.

Final report

ISBN: 978-1-921845-40-6
Author: Brian Jones

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