title: The role of electron transport in the defence response of the South African abalone, Haliotis midae.
abstract: In order to establish health management systems for farmed abalone, it is necessary to understand how the abalone immune system functions and responds to stimulation. Two electron transport system genes, cytochrome b and cytochrome c oxidase III, were found to be upregulated in a cDNA microarray experiment performed on haemocytes from immune-stimulated abalone (Arendze-Bailey, unpublished). The current study sought to elucidate the role of these genes, and thus the electron transport system, in the abalone immune response by specifically inhibiting cytochrome b with antimycin A and measuring haemocyte immune parameters in vivo. Antimycin A did not decrease haemocyte cell viability, but halved cellular ATP from 4 x 10(12) nM/cell to 2 x 10(12) nM/cell (p < 0.05, unpaired t-test). Inhibition of electron transport resulted in a 0.6 fold increase in cellular superoxide levels (p < 0.05, unpaired t-test), while phagocytosis dropped by nearly 50% (p < 0.05, ANOVA) and the ability of haemocytes to kill bacteria was also reduced. Since cytochrome b and cytochrome c oxidase III expression is upregulated in immune-stimulated abalone, and inhibition of electron transport resulted in a decreased immune response in vivo, we conclude that the abalone immune response is dependent on electron transport and that oxidative phosphorylation plays a role in the immune response following stimulation.
authors.affiliation: Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch 7700, South Africa.
authors.forename: Marike Janse
authors.initials: MJ
authors.lastname: van Rensburg
authors.forename: Vernon E
authors.initials: VE
authors.lastname: Coyne
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000968:Antimycin A / Q000494:pharmacology; D001419:Bacteria / Q000276:immunology; D002470:Cell Survival / Q000187:drug effects; D004579:Electron Transport / Q000276:immunology*; D049851:Gastropoda / Q000187:drug effects / Q000276:immunology*; D006434:Hemocytes / Q000187:drug effects / Q000382:microbiology; D010587:Phagocytosis / Q000187:drug effects; D013481:Superoxides / Q000378:metabolism
chemical_list: D013481:Superoxides; D000968:Antimycin A; D000255:Adenosine Triphosphate