A review of the potential role of tumour-promoting compounds produced by Lyngbya majuscula in marine turtle fibropapillomatosis
AbstractHarmful algal blooms (HABs) have increased in abundance
and severity in recent decades. Whereas the implications for human impacts and intoxication resulting from blooms have been extensively studied, the ecological implications of these microalgae are less
well understood. Many HAB species produce biologically active, secondary metabolites and the fate of these toxins through the foodweb is generally not well understood unless it culminates in extensive fish mortalities
or human poisonings. This review focusses on one HAB species, the cyanobacterium Lyngbya majuscula, and presents a hypothetical role for its involvement in fibropapillomatosis (FP), a neoplastic disease of marine
turtles. FP is expressed as benign tumours that grow both internally and externally on marine turtles, preventing vision, movement and organ function. The aetiology of FP is currently not conclusively understood, but virus material has been associated with tumours and previous
studies have suggested a role for naturally produced tumour promoters. In this review, we present a hypothesis regarding the involvement of L. majuscula in FP, either through direct intoxication and action of
tumour-promoting compounds or indirectly by causing seagrass loss and compromised immune function, thus leaving the turtles more susceptible to disease.