Prorocentrum concavum

Preliminary results on toxicity of 3 species of Caribbean dinoflagellates have been reported, namely those on Gambierdiscus toxicus (25), Prorocentrum concavum (as cf. lima) (26), and mexicanum (as rhathymum) (27). A more detailed description of the effects of ether-soluble and water-soluble toxins from the same strain of toxicus on guinea pig ilea are presented elsewhere in... 

Toxicity of crude fractions from Prorocentrum concavum. All four crude fractions extracted from concavum (SIU strain 364) (Figure 3b) consistently contained potent toxln(s). The results of mouse bloassay of these fractions are Included in Tables IV. Corresponding dose response curves and LD q s are shown in Figure 4. 

Table IV. Bioassay of Crude Ether Soluble Acetone Filtrate (ESAF), Ether Soluble Acetone Precipitate (ESAP), Water Soluble Acetone Filtrate, (WSAF), and Water Soluble Acetone Precipitate (WSAP) From Prorocentrum concavum Using 10 Female Mice for Each (ip) Injected Dose.

Figure 4. Dose response curves representing per cent mortality (within 48 hours) of approximately 20 g mice (CRE CD BR ICR) injected with specified doses of ether soluble acetone filtrate (ESAF), ether soluble acetone precipitate (ESAP), water soluble acetone filtrate (WSAF), and water soluble acetone precipatate (WSAP) from Prorocentrum concavum (SIU 364). Each dose was administered by ip injection into 10 mice. LD50S were determined using probit analysis. A correlation coefficient (R) is provided for each LD5Q.

Table V. A Comparison of The Four Crude Fractions and Their Respective Toxic Components From Prorocentrum concavum Using Analytical and Preparative TLC.

Our observations strongly suggest that Prorocentrum concavum and Gambierdiscus toxicus are major contributors of toxins to the reef and inshore ecosystems. We believe that these two species produce at least 4 (up to 7) separate toxins which may eventually... 

Prorocentrum concavum Fukuyo and mexicanum Tafall) from the... 

Figure 6. Growth of Prorocentrum concavum in (a) ESNW and (b) ESAW both supplemented with soil and macroalgae extracts. Controls ( ), Chaetomorpha extract ( ), Dictyota extract (A), Turbinaria extract ( ), and soil extract (O).

Okadaic acid] Prorocentrum concavum PP1, PP2A [hepatoxic,... 

Hu, T, Marr, J., de Freitas, A. S. W., Quilliam, M. A., Walter, J. A., Wright, J. L. C., and Pleasance, S. (1992b) New diol esters isolated from cultures of the dinoflagellates Prorocentrum lima and Prorocentrum concavum. Journal of Natural Products, 55, 11, 1631-1637. 

Dickey, R.W. et al.. Identification of okadaic acid from a Caribbean dinoflagellate. Prorocentrum concavum, Toxicon, 28, 371, 1990. 

Hu, T. et al.. New diol ester (of okadaic acid) isolated from cultures of Prorocentrum lima and Prorocentrum concavum, J. Nat. Prod., 55,1631, 1992. 

Crayfish nerve cord (CNC) has been used successfully as an assay for the extracts of the dinoflagellate Prorocentrum concavum (Miller et al. 1986). Three of the P. concavum extracts reduced the activity of the CNC. Purified CTX from moray eel induce spontaneous action potentials upon the node of Ranvier of frog isolated nerve fibers under current and voltage clamp conditions. This spontaneous activity Is reversible upon removal of the toxin from the external solution (Benoit et al. 1986). The postulated reason for this activity will be explained in the pharmacology section of this chapter. 

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