percent of their totsil excretory nitrogen in the form of trimethylamine 

 oxide. There are data to show that not all teleosts excrete large ajno\ints 

 of trimethylamine oxide. Wood (I958) showed that trimethylamine oxide 

 made up only a small fraction of the excreta of sculpin, Leptocottus 

 armatus , starry flounder, Platichthys stellatus, and blue sea-perch, 

 Taeniotoca lateralis . 



Ogilvie and Warren (1957) reported that trimethylamine oxide 

 may originate in the killifish, Fundulus heteroclitus , by an endogenous 

 process. They offered this as an explanation for the apparent accxomula- 

 tion of the oxide in the tissues of fasting animeils and of animals on an 

 oxide-free diet. This interpretation is probably incorrect, since the 

 oxide content was reported in \mits of mg. N/lOO g. flesh and no consider- 

 ation was given the possibility that the animals may have lost weight and 

 thus have shown an apparent increase in tissue oxide. 



It has been presumed that if trimethylamine oxide is synthesized 

 by marine teleosts, the last step will involve the conversion of trimethyl- 

 amine to trimethylamine oxide. Kapeller-Adler and Vering (I93I) reported 

 that aji enzyme system to catalyze this reaction is lacking in teleosts and 

 amphibia. Such an enzyme system has been demonstrated in man and in other 

 mammals (Lintzel 1935, Norris and Benoit 19i<-5b, Tarr 19i)-l). 



Trimethylamine oxide from an exogenous source . — Benoit and Norris 

 (19^5) showed that young salmon raised in a marine environment on an oxide- 

 free diet do not accumulate trimethylamine oxide in muscle tissue. When 

 the salmon were fed a diet containing oxide, some retention resulted. 

 Hashimoto emd Okaichi (1958a, b) reported that dietary trimethylamine 

 oxide is accvunulated in the niuscles of the goldfish, Carassius auratus , 

 and the eel, Anguilla japonica ; however, when these fish were fed an 

 oxide-free diet, the oxide was not found in the muscle. Okaichi, Manabe, 

 and Hashimoto (1959) reported that the globefish, Fugu niphobles , and 

 filefish, Monacanthus cerrhif er . acciamulate ingested trimethylamine oxide 

 in their tissues, whereas the jack mackerel, Trachvtrus .laponicus , does not. 



If we accept this idea that trimethylamine oxide in the food is 

 accumulated in the tissue of fishes, then we should look for the synthetic 

 or metabolic source of the oxide at some point in the food chain. Consider- 

 ing the food chain in reverse, we find that the larger teleosts utilize 

 smaller fishes and other larger marine animals as food; these animals 

 utilize the zooplankton, the zooplankton utilize the phytoplankton, and the 

 phytoplankton synthesize their food by photosynthesis. The first point in 

 the food chain where trimethylamine oxide is found is in the zooplankton. 

 The oxide fotind in zooplankton could get there by two routes. The simpler 

 would be the conversion of the trimethylamine found in the food — marine 

 plants (Channing and Young 1953, Kapeller-Adler and Vering 193l)--to the 

 oxide by the zooplankton. The more complex route woiold involve the synthesis 

 of the oxide in the zooplankton from smaller fragments. It appears that a 

 study of zooplankton in which the trimethylamine oxidase system and trans- 

 methylation systems are investigated might give vsJ-uable information on this 



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