Phosphagen and Protozoa

ABSTRACT The comparative investigations of Eggleton and Eggleton(6), Meyerhof and Lohmann (11), Meyerhof(10), and Needham, Needham, Baldwin and Yudkin(12) have established a considerable body of information concerning the distribution of the phosphagens in the animal kingdom, and the character and implications of this knowledge have recently been analysed by Needham and Needham (13). But from all discussions hitherto, any mention of the Protozoa has been absent. This gap in our knowledge is unfortunate for two reasons, firstly because from a phylogenetic point of view it would be very desirable to ascertain the lower limit of distribution of such important compounds, and secondly because the Protozoa, or at least certain examples of them, would afford an interesting test of any possible association between phosphagen metabolism and ciliary, as well as muscular movement. With regard to the first of these reasons, the Coelenterates yielded interesting results in the work of Needham, Needham, Baldwin and Yudkin(12), for whereas a Cteno-phore, Pleurobrachia pileus, contained considerable amounts of arginine phosphate (43 per cent, of the free and labile water-soluble phosphorus), none was discoverable in the Actinozoa, Anthea rustica and cereus. Further work on the phosphagen of the Coelenterates would be very useful, but it is perhaps significant in this connection that Kutscher and Ackermann (9), though able to isolate free arginine from many marine invertebrates, could only obtain guanidine and agmatine from Geodia gigas. The question whether phosphagen was to be found elsewhere than in the Metazoa clearly merited examination. And with regard to the second of the reasons given above, some indications were found by Needham, Needham, Baldwin and Yudkin (12) that phosphagen might occur in situations primarily characterised by ciliary activity, e.g. the swimming gastrulae and plutei of echinoids.