Occurrence of tetrodotoxin in the flatworm Planocera multitentaculata

Miyazawa, Keiji; Jeon, Joong Kyun; Maruyama, Junichi; Noguchi, Tamao; Ito, Keiji; Hashimoto, Kanehisa

doi:10.1016/0041-0101(86)90027-9

Cited by 71 publications

(31 citation statements)

References 18 publications

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“…Hence, TTX of bacterial origin is considered to accumulate in the puffer via food webs (Yasumoto et al 1992). The screening of various marine organisms for TTX revealed that this toxin is widely distributed in marine organisms, some species of which could be components of the diet of puffer Miyazawa et al 1986). These studies also showed that the trumpet shell Charonia sauliae accumulates TTX by ingesting the TTX bearing starfish Astropecten polyacanthus (Narita et al 1984).…”

Section: Possible Mechanism By Which Pufferfish Become Toxic: a Modelmentioning

confidence: 99%

Paralytic Shellfish Poisoning Toxins: Biochemistry and Origin

Kodama

2010

Aqua-BioSci. Monogr. (ABSM)

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Plankton feeders such as bivalves often become toxic. Human consumption of the toxic bivalve causes severe food poisoning, including paralytic shellfish poisoning (PSP) which is the most dangerous because of the acuteness of the symptoms, high fatality and wide distribution throughout the world. Accumulation of PSP toxins in shellfish has posed serious problems to public health and fisheries industry. The causative organisms of PSP toxins are known to be species of dinoflagellates including those belonging to the genus Alexandrium, Gymnodinium catenatum and Pyrodinium bahamense var. compressum. Bivalves accumulate PSP toxins during a bloom of these dinoflagellates. Thus, the dinoflagellate toxins have been considered as being concentrated in bivalves through food web transfer. However, field studies on the toxin level of bivalves in association with the abundance of toxic dinoflagellates could not support the idea. A kinetics study on toxins by feeding experiments of cultured dinoflagellate cells to bivalves also showed similar results, indicating that toxin accumulation of bivalves is not caused by simple accumulation of toxins due to food-web transfer. Based on the discovery of toxin-producing bacterium in the cells of toxic dinoflagellates, this study suggests that PSP toxins in toxic dinoflagellates are catabolites of bacterial substance in dinoflagellate cells. On the other hand, tetrodotoxin (TTX), a puffer toxin, is reported to be produced by some species of bacteria. Thus, the origin of TTX of puffer is considered to be bacteria. However, the mechanism for puffer to possess TTX through bacteria is unknown. The present study revealed that organisms bearing either TTX or PSP toxins possess both toxins, although the proportion of both is different among the specimens. In fact, a significant level of TTX is detected in A. tamarense. In addition, TTX-like toxin-producing bacteria are found to be infected in the liver of toxic specimens of puffer. These findings strongly suggest that a similar mechanism between bacteria and toxic organisms is involved in the production of TTX and/or PSP toxins in toxic organisms.

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Section: Possible Mechanism By Which Pufferfish Become Toxic: a Modelmentioning

confidence: 99%

Paralytic Shellfish Poisoning Toxins: Biochemistry and Origin

Kodama

2010

Aqua-BioSci. Monogr. (ABSM)

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“…For a biodiverse assemblage of animal and microbial species, TTX serves as a chemical defense or venom (Kim et al, 1975;Sheumack et al, 1978;Miyazawa et al, 1986;Thuesen et al, 1988;Ritson-Williams et al, 2006). It acts as a potent neurotoxin by binding to and blocking voltage-gated sodium channels on nerve and muscle cell membranes (Hille, 2001).…”

Section: Ecological Consequences Of Mixture Suppression and Context-mentioning

confidence: 99%

The scent of danger: arginine as an olfactory cue of reduced predation risk

Ferrer

Zimmer

2007

Journal of Experimental Biology

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SUMMARY Animal perception of chemosensory cues is a function of ecological context. Larvae of the California newt (Taricha torosa), for example, exhibit predator-avoidance behavior in response to a chemical from cannibalistic adults. The poison tetrodotoxin (TTX), well known as an adult chemical defense, stimulates larval escape to refuges. Although they are cannibals,adult newts feed preferentially on worms (Eisenia rosea) over conspecific young. Hence, larval avoidance reactions to TTX are suppressed in the presence of odor from these alternative prey. The free amino acid,arginine, is abundant in fluids emitted by injured worms. Here, we demonstrate that arginine is a natural suppressant of TTX-stimulated larval escape behavior. Compared to a tapwater control, larvae initiated vigorous swimming in response to 10–7 mol l–1 TTX. This excitatory response was eliminated when larval nasal cavities were blocked with an inert gel, but not when gel was placed on the forehead (control). In additional trials, a binary mixture of arginine and 10–7 mol l–1 TTX failed to induce larval swimming. The inhibitory effect of arginine was, however, dose dependent. An arginine concentration as low as 0.3-times that of TTX was significantly suppressant. Further analysis showed that suppression by arginine of TTX-stimulated behavior was eliminated by altering the positively-charged guanidinium moiety, but not by modifying the carbon chain, carboxyl group, or amine group. These results are best explained by a mechanism of competitive inhibition between arginine and TTX for common, olfactory receptor binding sites. Although arginine alone has no impact on larval behavior, it nevertheless signals active adult predation on alternative prey, and hence, reduced cannibalism risk.

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“…are known predators of commercially important oysters (Arakawa 1970, Galleni 1976, Newman et al 1993) and the mussel Mytilus galloprovincialis (Galleni et al 1980). In addition, several planocerid species accumulate high concentrations of tetrodotoxin in their eggs -as a possible defense against predators -and in the pharynx, where it has been shown to aid in capturing mobile prey (Miyazawa et al 1986, 1987, Tanu et al 2004, Ritson-Williams et al 2006, Yamada et al 2017). There have also been several reports of dogs in New Zealand having been affected after feeding on the opisthobranch Pleurobranchaea maculata which had washed up on the beach after having been toxified by the polyclad Stylochoplana sp.…”

Section: Introductionmentioning

confidence: 99%

A molecular framework for the taxonomy and systematics of Japanese marine turbellarian flatworms (Platyhelminthes, Polycladida)

Tsunashima¹,

Morio²,

Yamada³

et al. 2017

Aquat. Biol.

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The order Polycladida comprises a highly diverse and cosmopolitan group of marine turbellarian flatworms. Owing to the great morphological diversity and the absence of a molecular phylogeny, the classification of this group has always been controversial. Here we seek to add resolution by reporting the results of molecular phylogenetic analysis based on sequences of the 28S ribosomal RNA gene, thus providing a framework for understanding relationships and the evolution of characters within the group. The phylogeny provides strong support for 10 and 7 distinct families within the suborders Acotylea and Cotylea, respectively. In addition, an analysis based on the mitochondrial gene sequences (cytochrome c-oxidase subunit I) reveals further details of the relationships within Acotylea, which were classified by morphological analysis, but not by 28S rRNA sequence-based analyses. These analyses also showed that several species corresponded to previously described genera based on morphological features and character combinations. We conclude that a classification of genera in Acotylea and Cotylea based on molecular phylogeny reflects the morphological diversity of these polyclad flatworms.

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Occurrence of tetrodotoxin in the flatworm Planocera multitentaculata

Cited by 71 publications

References 18 publications

Paralytic Shellfish Poisoning Toxins: Biochemistry and Origin

Paralytic Shellfish Poisoning Toxins: Biochemistry and Origin

The scent of danger: arginine as an olfactory cue of reduced predation risk

A molecular framework for the taxonomy and systematics of Japanese marine turbellarian flatworms (Platyhelminthes, Polycladida)

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