Variation of 2,3.4-tribromopyrrole and its sodium sulfamate salt in the hemichordate Saccoglossus kowalevskii

Abstract

We quantified spatial and temporal patterns of brominated pyrrole variation in the common marine hemichordate worm Saccoglos5u5 kowaJevskii. Using fast·atom bombardment mass spectrometry we found a novel sodium sulfamate salt (C4HBr3N03SNa) of 2,3,4-tribromopyrrole (TBP) that predominated over 2,3,4-TBP (II % vs 0.6% ash-free dry wt). There was no relationship between the total amounts of the 2 compounds. The sulfamate salt was concentrated in the hepatic region (50 %), a possible site of synthesis or storage. 2,3,4-TBP was highest (1.5 'Yo) in the proboscis and tail, which are exposed to predation. No seasonal pattern was apparent for the sulfamate salt over a 30 mo sampling period. 2,3,4-TBP exhibited temporal inCTeases, possibly associated with spawning. The sulfamate salt was not detectable by GCIMS techniques, raising the possibility that sulfonati.on may be more common than realized. The sulfamate salt may serve as the non-autotoxic stable precursor to the more volatile 2,3,4-TBP.

Do brominated natural products defend marine worms from consumers? Some do, most don’t

“…1; Table 1). Many of these species have been reported to contain a variety of brominated compounds, including various pyrroles, phenols, and substituted alkanes (Fielman et al 1999). Of these nine species, only two were unpalatable ( Fig.…”

“…Worm tissues vary in their concentration of brominated metabolites (Goerke et al 1991;Yoon et al 1994;Fielman and Targett 1995;King et al 1995), and in some species, body portions closest to the surface, where they may be at more risk of predation, contain elevated concentrations of compounds relative to whole body values. In these situations, natural concentrations based on whole body values could be lower than the ecologically meaningful concentrations that a consumer would encounter when attacking these most chemically rich portions of the worm.…”

“…Several worms consumed in our feeding assays produce brominated metabolites hypothesized to serve as chemical defenses against consumers (Woodin et al 1987;Yoon et al 1994;Fielman and Targett 1995;Fielman et al 1999;Cowart et al 2000). To ensure that the specific species and individuals we used contained these metabolites, we analyzed our samples for brominated metabolites by gas chromatography mass spectrometry (GC/MS) (identifying brominated compounds by the presence of molecular ion peaks separated by 2 atomic mass units for the two isotopes of bromine).…”

“…Numerous species, particularly worms, from the Northeast Pacific (Woodin et al 1987;Woodin et al 1993), Northwest Atlantic Corresponding author (mark.hay@biology.gatech.edu). gett 1995; King et al 1995;Giray and King 1997a), West-central Atlantic (Ashworth and Cormier 1967;Woodin et al 1997;Fielman et al 1999;Cowart et al 2000), and Eastern Atlantic (Weber and Ernst 1978;Emrich et al 1990;Goerke and Weber 1990;Goerke et al 1991;Jensen et al 1992) contain these compounds. As an indication of the commonness of this phenomenon, Fielman et al (1999) investigated 40 species of infaunal invertebrates and found that 43% of the species contained halogenated metabolites.…”

“…Several authors have predicted (Woodin et al 1987) or provided correlative evidence (Yoon et al 1994;Fielman and Targett 1995;Fielman et al 1999;Cowart et al 2000) that these brominated compounds could function as predator deterrents. For example, the highest concentration of brominated metabolites in the annelids Notomastus lobatus and Thelepus extensus and the hemichordate Saccoglossus kowalevskii are in body parts that are nearest to the substrate surface and, thus, at greater risk of predation from fishes or crabs (Goerke et al 1991;Yoon et al 1994;Fielman and Targett 1995). However, when worms that produce brominated compounds have been exposed to predators, outcomes have been variable.…”