Algal Natural Product Toxins

Prymnesium parvum is a flagellated alga which is widely distributed across brackish waters.   P. parvum has been blamed for large scale fish kills worldwide, including in fish farms in Texas and Norwegian fjords. It is also a local problem for us in the Norfolk Broads in the UK.  Harmful algal blooms of P. parvum have serious implications for the local environment and rural economy in Norfolk, with fish kills having detrimental effects on angling and tourism.  We are currently working with the Environment Agency to develop useful tools to warn of an impending bloom, as well as to minimise the impact of a bloom once it has started.

Edward Hems and Ben Wagstaff on a field trip in Norfolk Broads.

Dead fish as a result of algal bloom in Norfolk Broads.

Fish has to be relocated to safe water.

The ichthyotoxins produced by P. parvum, prymnesins 1 and 2, are highly toxic to gill breathing organisms. Both toxins have a 90-carbon chain including a 14-ring ladder-frame polyether backbone elaborated with an unusual terminal di-alkyne. Prymnesins were the first algal glycosylated natural products incorporating galactopyranose, galactofuranose, ribofuranose and xylofuranose.

Structures of P. parvum derived toxic metabolites prymnesin-1 and prymnesin-2.

The emphasis of our research is in:

  • Finding synthetic routes to prymnesin fragments from the di-alkyne back to the polyether rings;
  • Developing systems for the direct detection of prymnesins at low concentration utilising fragments containing the terminal di-alkyne;
  • Synthesis of glycosylated prymnesin fragments which potentially can be used for
  • Developing an antibody based detection system and elucidation of some of the undefined stereochemistry in the toxin.

We are also investigating the sugar nucleotide mutases found within the organism, in particular UDP-galactopyranose mutase which catalyses biosyntheis of UDP-galactofuranose. The latter has been chemoenzymatically synthesised in our lab to be used as a standard in an algal sugar nucleotide profiling.