Pectenotoxin-1 and

FIGURE 16.11 Proposed fragmentations observed in positive ion MS/MS spectra of pectenotoxin-1 and pectenotoxin-11. Ions in bold text arise from PTXll ions in italic text arise from PTXl, and ion in parentheses are of very low abnndance. All transitions shown involved loss of water (18 amn) nnless otherwise indicated. 

Terao, K., et al., Histopathological studies on experimental marine toxin poisoning. I. Ultrastructural changes in the small intestine and liver of suckling mice induced by dinophysistoxin-1 and pectenotoxin-1, Toxicon, 24, 11-12, 1141, 1986. 

Pectenotoxins were easily discernible by their strong UV absorption. The presence of 5 components was recognized by TLC and HPLC. Pectenotoxin-1 was isolated as white crystalline solid m.p. 208-209 ... 

The secondary ionization mass spectra of pectenotoxin-3 and -4 gave a (M+ +H) ion at m/z 875, indicating that they share the same formula with pectenotoxin-1. The mass spectrum of pectenotoxin-5 gave a (M +H) ion at m/z 877, suggesting that it is a dihydro derivative of either of pectenotoxin-1,-3, and -4. Further structural elucidation of these components is under way. 

Suzuki, T, Igarashi, T, Ichimi, K., Watai, M., Suzuki, M., Ogiso, E., and Yasumoto, T. 2005a. Kinetics of diarrhetic shellfish poisoning toxins, okadaic acid, dinophysistoxin-1, pectenotoxin-6 and yessotoxin in scallops Patinopecten yessoensis. 

Suzuki, T, and Yasumoto, T. 2000. Liquid chromatography-electrospray ionization mass spectrometry of the diarrhetic shellfish-poisoning toxins okadaic acid, dinophysistoxin-1 and pectenotoxin-6 in bivalves. J ChromatogrA 874, 199-206. 

The sponge Halichondria okadai contains a polyether metabohte named okadaic acid (16) that was also isolated as a causative agent of diarrhetic shellfish poisoning (DSP) from mussels and other bivalves (14). However, the real producers are dinoflagellates of the genus Dinophysis. It is a potent cancer promoter that was found to be caused by inhibition of protein phosphatases 1 and 2A at nanomolar levels. Pectenotoxins are also involved in DSP and are produced by Dinophysis spp. pectenotoxin 2 (17) inhibits actin polymerization (14). 

The consumption of shellfish (scallops and mussels) harvested during late spring to early summer fiom the northeastern region of Japan quite often results in what is commonly known as diarrhetic shellfish poisoning. An initial chemical investigation of the toxic mussels resulted in the identification (86) of okadaic acid [108], dinophysistoxin 1 (DTXj) [109] and two toxins of unknown structures. In a later study (87), chemical structures of three new polyether toxins, dinophysistoxin- 3 (DTX3)[110], pectenotoxin-1 [111 ] and pectenotoxin-2 [112] were reported. 

It has been shown in experimental animals that pectenotoxin-1 (PTX-1) is hepatotoxic and induces rapid necrosis of hepatocytes, with a pathological action similar to that of phalloidin. In rats intraperitonially injected with PTXs, the liver finally appears granulated and the hepatocytes contain many vacuoles. 

Kuuppo, P. et al., Pectenotoxin-2 and dinophysistoxin-1 in suspended and sedimenting organic matter in the Baltic Sea, Limnol. Oceanogr., 51, 2300, 2006. 

FIGURE 16.10 LC-MS/MS product ion spectra obtained for the [M+NHJ ions m/z 892.5) of pecteno-toxin-11 (a) and pectenotoxin-1 (b). All m/z values have been rounded off. 

PTX (1) also caused a significant reduction in the actin cytoskeleton as with other polyol and polyether toxins such as pectenotoxin-6 and maitotoxin [33]. Thus, the cytoskeleton is suggested to be an early target for the toxic effect of such toxins. Furthermore, the skin tumor promoter activity of palytoxin has gathered attention. Notably, palytoxin did not activate protein kinase C but extracellular signal-regulated kinase (ERK) through a mechanism that involves inactivation of an ERK phosphatase in keratinocytes derived from initiated mouse skin [34]. 

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