Lusitanian nemertean species in Lough Hyne Marine Reserve: Paradrepanophorus crassus and Punnettia splendida

Trowbridge, Cynthia D.; Little, Colin; Stirling, Penny; Pilling, Graham M.; Dlouhy-Massengale, Brittney

doi:10.1017/s1755267213000328

Cited by 2 publications

(1 citation statement)

References 10 publications

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“…Paradrepanophorus crassus (abbreviated Pc ), the subject of this paper, is one of these benthic species. Pc has been reported to occur on British, Irish and Spanish Atlantic coasts as well as in the Mediterranean Sea [ 18 , 19 , 20 ]. While the presence of numerous tiny stylets in the proboscis of polystiliferans has been noted, the only previous report of a toxin in this group was Bacq’s observation that an aqueous extract of this species displayed “amphiporine” activities, stimulating skeletal muscle and autonomic synapses [ 3 , 4 ].…”

Section: Introductionmentioning

confidence: 99%

Discovery of the Nicotinic Receptor Toxin Anabaseine in a Polystiliferan Nemertean

Kem

Rocca

Johnson

et al. 2023

Toxins

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Nemerteans (also called Nemertines) are a phylum of predominantly marine worms that use toxins to capture prey and to defend themselves against predators. Hoplonemerteans have a proboscis armed with one or more stylets used in prey capture and are taxonomically divided into Order Monostilifera, whose members possess a single large proboscis stylet, and Order Polystilifera, whose members have multiple small stylets. Many monostiliferans contain alkaloidal toxins, including anabaseine, that stimulate and then desensitize nicotinic acetylcholine receptors that are present in all animals. These compounds also interact with pyridyl chemoreceptors in crustaceans, reducing predation and larval settlement. Anabaseine has been a lead compound in the design of alpha7 nicotinic acetylcholine receptor agonists like GTS-21 (also called DMXBA) to treat disorders of cognition such as Alzheimer’s disease and schizophrenia. These drug candidates also display anti-inflammatory activities of potential medical importance. Most polystiliferans live deep in open oceans and are relatively inaccessible. We fortunately obtained two live specimens of a large benthic polystiliferan, Paradrepanophorus crassus (Pc), from the coast of Spain. MS and NMR analyses of the Ehrlich’s reagent derivative allowed identification of anabaseine. A spectrophotometric assay for anabaseine, also based on its reaction with Ehrlich’s reagent, revealed high concentrations of anabaseine in the body and proboscis. Apparently, the biosynthetic mechanism for producing anabaseine was acquired early in the evolution of the Hoplonemertea, before the monostiliferan-polystiliferan divergence.

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