The role of electron transport in the defence response of the South African abalone, Haliotis midae.
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be upregulated in a cDNA microarray experiment performed on haemocytes from immune-stimulated abalone (Arendze-Bailey, unpublished).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.
van Rensburg
Marike Janse
MJ
Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch 7700, South Africa.
Coyne
Vernon E
VE
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
D013481:Superoxides; D000968:Antimycin A; D000255:Adenosine Triphosphate