The cytotoxic effect of Glycerophospholipid: Cholesterol Acyltransferase (GCAT) on mammalian and fish cell lines in vitro

Glycerophospholipid: cholesterol acyltransferase (GCAT) is an enzyme produced by the bacteria Aeromonas salmonicida. A. salmonicida is the causative agents of the fish disease furunculosis and GCAT is an important enzyme when considering the virulence and progression of this disease. This study aims to show how the cytotoxic affects of the GCAT enzyme can vary between mammalian and fish cells. Both cloned and crude native forms of GCAT were exposed to mammalian and fish cell lines and observed for signs of damage over a 24 hour period. The cloned GCAT extraction was exposed to both fish and mammalian erythrocytes, while the crude native form was exposed to just mammalian erythrocytes to check for cytolytic activity. This study shows that GCAT produced from an A. salmonicida A-layer mutant is capable of lysing mammalian erythrocytes, as well as Chinese Hamster Ovary (CHOs) cell lines and lysis of Goldfish Skin (GFSK) cell lines. However once a cloned, purer, sample of GCAT was produced by transformation of the GCAT gene into E. coli, the GCAT product was incapable of lysing CHO cell lines but retained its ability to lyse fish cells in the form of Rainbow Trout Gonad (RTG) cell lines. The purified GCAT also demonstrated low levels of haemolysis with both mammalian and fish erythrocytes