Biochemical characterisation of potentially contagious haemic neoplasia occurring in the Baltic clam Limecola balthica

Abstract

Occurring in marine invertebrates haemic (leukemia-like) neoplasia, a disease of potentially infectious nature, arises from genome instabilities leading to multilevel malfunctions and unregulated cell division of presumably haemocyte precursors. As its biochemical characterisation remains unknown, we here present results describing selected physiological and biochemical aspects of the disease measured in neoplastic and healthy clams Limecola balthica. Activities of adenosine deaminase (ADA), alkaline phosphatase (ALP) and FAA levels were measured in haemolymph but no differences in ADA and ALP activities between healthy and neoplastic clams were found. In both clam groups nine FAAs were detected with Asp, Glu, Pro, Ser constituting over 90% of total FAA content. Significantly higher Gln level was detected in leukemic-like clams suggesting an essential role of this FAA in cancer energy production. In neoplastic cells, an impairment of mitochondrial metabolism was observed as a decrease in mitochondrial oxygen consumption and lower cytochrome c oxidase activity. Neoplastic clams were also characterised by significantly higher concentration of ROS, but no elevated response of the oxidative stress markers were found suggesting an efficient antioxidant response. Finally, we, for the first time, report high levels of corticosterone and lower amounts of dehydrocorticosterone, cortisol and cortisone in healthy clams with elevated cortisol level found in neoplastic individuals.