Dept. Biological Sciences, Macquarie University , Sydney , NSW 2109.

Phone: (02) 9850 8205

Fax: (02) 9850 8245

saladail@bio.mq.edu.au

 

My research aims to identify the components of Sydney rock oyster immune system, in order to understand the interaction between oysters and their pathogens. In all animals, the immune system comprises cellular and humoral elements that act together to protect the organism against pathogens. In many invertebrates, circulating blood cells (hemocytes) participate in internal defence. So, before the effects of immunomodulatory molecules on the immune system of oysters could be studied, it was first necessary for me to characterise the immune functions of hemocytes. Morpho-functional studies via light and electron microscopy were carried out. Four types of hemocyte were identified: hemoblasts, granulocytes, hyalinocytes and serous cells. I have then characterised the responses of oyster immune cells during infection, and investigated the interaction between hormones and the immune response.

My research suggests that environmental stressors may depress the oyster's ability to defend themselves against infections. In invertebrates, the primary response to stress is characterized by the release of neuroendocrine messengers such as catecholamines. In order to investigate the relation between the endocrine system and the immune system, noradrenaline was injected into oysters, and various immune parameters were analysed. I am also studying the phenoloxidase system in depth. The phenoloxidase system is a primary humoral defensive response in a number of invertebrates, including molluscs. I am testing the effects of pathogen-associated molecular patterns (PAMPs), detergents, serine proteases and enzyme inhibitors on this system.

My project is also extending our characterization beyond factors like phagocytosis and phenoloxidase. Currently, most of our knowledge on the oyster immune system is based on various biological activities. The molecular features of immune effectors are largely uncharacterized. A number of ESTs will be selected for designing primers to be used in qRT-PCR. These ESTs are know to be involved in the oyster's immune reactions as well as in stress-mediated responses. The relative expression of these genes will be analysed by qRT-PCR. The analysis of gene expression during bacterial challenge and after noradrenaline injection will be used to extend the results obtained thus far in my PhD research.

	Oyster hyalinocytes
	Stem cell oyster
	Phalloindin stain oyster's hemocytes