Toxin: Saxitoxin

 

Causative Organisms: Gymnodinium sp. (1*,2,), Alexandrium spp. (1*,3,6), Pyrodinium sp. (1*, 16, 19, 21)

Toxicity: 20 STX derivatives have also been identified (3*, 4)
The toxin gonyautoxin (GTX) is often found with STX and is believed to be a congener of the latter (21)

Mode of Activity: blocks voltage-gated sodium channels of nerve and muscle membranes at nanomolar concentrations (11*,13*, 16, 17*)

Cyst production has been verified in Gymnodinium sp. (8), Alexandrium spp. (6*, 7), and Pyrodinium sp. (22*)

Geographic range: 60o N – 55 oS (2, 6*, 8, 14, 19, 22, 25*)
 

 

Species:
  1. A. lusitanicum, A. tamarense (3), A. minutum (6), A. fundyense (1), G. catenatum (2), P. bahamense (19, 21), P. bahamense var. compressum (22*).

 

Impacts of Toxin

Marine Food Web:

STX is bio-magnified and/or bio-transformed up the food web (1*)

Behavioral: No current information is available

 

Economic:

Closure of shellfish beds from harvesting during blooms of the causative organisms and also when STX is detected in shellfish
Economic losses in 2005 from the closure of shellfish beds were estimated to be $50 million for the MA shellfish industry alone (1*,18)
The seafood industry in the Philippines suffered a great loss of about USD 300,000 per day during the height of a three month red tide occurrence in Manila Bay in 1988.  During the 1988 bloom, Japan and Singapore banned shrimp imports from the Philippines.  Muscle farmers also sustained a loss during this period (23)

 

Human Health

Name of Malady: Paralytic shellfish poison (PSP)

Symptoms:  Occur within 30 minutes to 3 hours after consumption of contaminated seafood
Symptoms include tingling and burning in face, lips and tongue, peppery taste, paraesthesia and numbness, mild headache and dizziness, muscular weakness, giddiness, incoherent speech, ataxia, motor incoordination, dysmetna, nausea and vomiting, respiratory difficulties and paralysis, hypoxia, hypercapma, and in extreme cases, death (1*, 17)

 *and references cited therein.  **MU (mouse unit): the amount of crude toxin that will kill a 20-gm in 15 minutes, or the LD50 of the population in 24 hours

 

References
  1. Bienfang, P.K. et al., 2011. Prominent Human Health Impacts from Several Marine Microbes: History, Ecology, and Public Health Implications. International Journal of Microbiology, 2011.
  2. Anderson, D.M. et al., 2005. Initial observations of the 2005 Alexandrium fundyense bloom in southern New England: General patterns and mechanisms. Deep Sea Research Part II: Topical Studies in Oceanography, 52(19-21), 2856–2876. 
  3. Hold, G.L. et al., 2001. Comparison of paralytic shellfish toxin (PST) production by the dinoflagellates Alexandrium lusitanicum NEPCC 253 and Alexandrium tamarense NEPCC 407 in the presence and absence of bacteria. FEMS Microbiology Ecology, 36(2-3), 223-234. 
  4. Gallacher, S. & Smith, E.A., 1999. Bacteria and Paralytic Shellfish Toxins. Protist, 150(3), 245-255. 
  5. http://soer.justice.tas.gov.au/2009/image/864/index.php
  6. Hansen, G., Daugbjerg, N. & Franco, J.M., 2003. Morphology, toxin composition and LSU rDNA phylogeny of Alexandrium minutum (Dinophyceae) from Denmark, with some morphological observations on other European strains. Harmful Algae, 2(4), 317-335. 
  7. Montresor, M., 1995. The life history of Alexandrium pseudogonyaulax (Gonyaulacales, Dinophyceae). Phycologia, 34(6), 444–448.  
  8. Blackburn, S.I., Hallegraeff, G.M. & Bolch, C.J., 1989. Vegetative reproduction and sexual life cycle of the toxic dinoflagellate Gymnodinium catenatum from Tasmania, Australia. Journal of Phycology, 25(3), 577-590.
  9. Taylor, F.J.R., 1985. The taxonomy and relationships of red tide flagellates. Toxic Dinoflagellates. Elsevier, New York, 11–26.
  10. http://www.sccoos.org/data/habs/species.php?specie=Alexandrium%20spp.
  11. Shimizu, Y., Hsu, C. & Genenah, A., 1981. Structure of STX in solutions and stereochemistry of dihydroSTXs. Journal of the American Chemical Society, 103(3), 605-609. 
  12. Schantz, E.J. et al., 1975. Structure of STX. Journal of the American Chemical Society, 97(5), 1238-1239.
  13. Hille, B., 1975. The receptor for tetrodotoxin and STX. A structural hypothesis. Biophysical Journal, 15(6), 615-619.  
  14. Morey-Gaines, G., 1982. Gymnodinium catenatum Graham (Dinophyceae): morphology and affinities with armoured forms. Phycologia, 21(2), 154–163. 
  15. Genenah, A.A. & Shimizu, Y., 1981. Specific toxicity of paralytic shellfish poisons. Journal of Agricultural and Food Chemistry, 29(6), 1289-1291.  
  16. Watson, D.H., 1998. Natural toxicants in food, Blackwell. 
  17. Whittle, K. & Gallacher, S., 2000. Marine toxins. British Medical Bulletin, 56(1), 236-253. 
  18. Anderson, D.M. et al., 2005. Initial observations of the 2005 Alexandrium fundyense bloom in southern New England: General patterns and mechanisms. Deep Sea Research Part II: Topical Studies in Oceanography, 52(19-21), 2856–2876.  
  19. Harada, T. et al., 1982. Confirmation of paralytic shellfish toxins in the dinoflagellate Pyrodinium bahamense var. compressa and bivalves in Palau. Bull. Jap. Soc. Sci. Fish, 48(6), 821–825. 
  20. Steidinger, K.A., Tester, L.S. & Taylor, F.J., 1980. A redescription of Pyrodinium bahamense var. compressa (B\öhm) stat. nov. from Pacific red tides. Phycologia, 19(4), 329–334.   
  21. Usup, G., Kulis, D.M. & Anderson, D.M., 1994. Growth and toxin production of the toxic dinoflagellate Pyrodinium bahamense var. compressum in laboratory cultures. Natural toxins, 2(5), 254–262. 
  22. Azanza, R.V. & Max Taylor, F.J.R., 2011. Are Pyrodinium Blooms in the Southeast Asian Region Recurring and Spreading? A View at the End of the Millennium. AMBIO: A Journal of the Human Environment, 30(6), 356-364.
  23. Corrales, R.A. & Maclean, J.L., 1995. Impacts of harmful algae on seafarming in the Asia-Pacific areas. Journal of applied phycology, 7(2), 151–162. 
  24. Maclean, J.L., 1977. Observations on Pyrodinium bahamense Plate, a toxic dinoflagellate, in Papua New Guinea. Limnology and Oceanography, 22(2), 234–254. 
  25. Negri, A. et al., 2003. Three Novel Hydroxybenzoate STX Analogues Isolated from the Dinoflagellate Gymnodinium catenatum. Chemical Research in Toxicology, 16(8), 1029-1033