Article

The Fate of Lyngbya majuscula Toxins in Three Potential Consumers

Smithsonian Marine Station, Fort Pierce, FL 34949, USA.
Journal of Chemical Ecology (Impact Factor: 2.75). 08/2005; 31(7):1595-606. DOI: 10.1007/s10886-005-5800-5
Source: PubMed

ABSTRACT

Blooms of Lyngbya majuscula have been reported with increasing frequency and severity in the last decade in Moreton Bay, Australia. A number of grazers have been observed feeding upon this toxic cyanobacterium. Differences in sequestration of toxic compounds from L. majuscula were investigated in two anaspideans, Stylocheilus striatus, Bursatella leachii, and the cephalaspidean Diniatys dentifer. Species fed a monospecific diet of L. majuscula had different toxin distribution in their tissues and excretions. A high concentration of lyngbyatoxin-a was observed in the body of S. striatus (3.94 mg/kg(-1)) compared to bodily secretions (ink 0.12 mg/kg(-1); fecal matter 0.56 mg/kg(-1); eggs 0.05 mg/kg(-1)). In contrast, B. leachii secreted greater concentrations of lyngbyatoxin-a (ink 5.41 mg/kg(-1); fecal matter 6.71 mg/kg(-1)) than that stored in the body (2.24 mg/kg(-1)). The major internal repository of lyngbyatoxin-a and debromoaplysiatoxin was the digestive gland for both S. striatus (6.31 +/- 0.31 mg/kg(-1)) and B. leachii (156.39 +/- 46.92 mg/kg(-1)). D. dentifer showed high variability in the distribution of sequestered compounds. Lyngbyatoxin-a was detected in the digestive gland (3.56 +/- 3.56 mg/kg(-1)) but not in the head and foot, while debromoaplysiatoxin was detected in the head and foot (133.73 +/- 129.82 mg/kg(-1)) but not in the digestive gland. The concentrations of sequestered secondary metabolites in these animals did not correspond to the concentrations found in L. majuscula used as food for these experiments, suggesting it may have been from previous dietary exposure. Trophic transfer of debromoaplysiatoxin from L. majuscula into S. striatus is well established; however, a lack of knowledge exists for other grazers. The high levels of secondary metabolites observed in both the anaspidean and the cephalapsidean species suggest that these toxins may bioaccumulate through marine food chains.

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    • "Nagle et al. (1998) found that malyngamides and majusculamides increased feeding at lower concentrations , but inhibited feeding at higher concentrations. While S. striatus may be able to bioaccumulate Lyngbya compounds with no apparent detrimental impact (Capper et al., 2005; Pennings and Paul, 1993a), sensitivity to, and thus avoidance of different species of benthic cyanobacteria may ultimately increase animal fitness. In palatability and associated biomass increase assays, S. striatus showed a preference for L. polychroa (now known as Okeania erythroflocculosa, Engene et al., 2013b) over L. cf. "
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    • "Saxitoxins are known as sodium channel blockers in the brain; however, the toxicity of the freshwater L. wollei is less studied than its marine congener L. majuscule. The marine L. majuscule is known to produce saxitoxins, and over 70 bioactive compounds such as microcolin B, ypaoamide, malyngolide, barbamide (Nagle and Paul 1998; Capper et al. 2005) and, in particular, immunosuppressive peptides like microlin A and B (Yasumoto 1998). The toxicity of these toxins towards the immune status in freshwater mussels is poorly understood at the present time. "
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