Physiology 445 



hematin-requiring Trypanosomidae should be useful for microbiological 

 assays. 



The synthesis of nicotinic acid (207, 223), adenine (223), pyridoxal, 

 and riboflavin (207) has been demonstrated in Chiloynonas Paramecium. 

 Synthesis of riboflavin, pantothenic acid and probably of biotin has been 

 reported for Tetrahy?7iena pyriformis on the basis of microbiological 

 assays (283), but these conclusions were later withdrawn (290). The syn- 

 thesis of p-aminobenzoic acid and inositol by T. pyriformis has been 

 reported on the basis of Neurospora assays (276). Synthesis of the former 

 would seem to be no advantage to the ciliate since p-aminobenzoic acid 

 apparently cannot replace pteroylglutamic acid as an absolute require- 

 ment. 



The requirements of various groups 



At present, little has been published on two major groups of the 

 phytoflagellates,^ the Chrysomonadida and Dinoflagellida. Earlier work 

 on Oikomonas termo (192) and dinoflagellates (13) was interrupted, and 

 although extensive investigations are in progress, the two orders offer quite 

 a variety of unsolved nutritional problems. Both groups include colorless 

 and chlorophyll-bearing species and a number of holozoic types, and both 

 are represented in fresh and salt water. Representatives of two other 

 orders, Heterochlorida and Chloromonadida, apparently are not yet avail- 

 able in pure cultures. 



Cyyptomonadida. So far, the chlorophyll-bearing cryptomonads have 

 been neglected in favor of Chilomonas paramedian, several strains of 

 which have been investigated. As nitrogen sources, ammonium salts are 

 satisfactory, nitrate is inadequate (73), and utilization of nitrate has not 

 been demonstrated. Reported chemoautotrophy (390) had not been con- 

 firmed (73). Although C. Paramecium has been grown in glycine and 

 acetate medium (186, 390), little is known about amino acids as nitrogen 

 sources or their possible value as sources of both carbon and nitrogen. 



Excellent carbon sources,^ added to a basal inorganic medium supple- 

 mented with thiamine (or its components), include acetate, ethanol, lac- 

 tate, and pyruvate (73, 222, 354). In such a medium, about 45 per cent of 

 the available acetate is oxidized while the rest is assimilated (224). With- 



'^ Current data on food requirements and metabolism of the phytoflagellates have 

 been discussed by Hutner and Provasoli (228). 



" Extending the earlier observation of Provasoli (467) with peptone media, B. K. 

 Swanson (1951. M. S. Thesis, University of Iowa) has tested various alcohols as carbon 

 sources for Chilomonas Paramecium in a simple medium. Several straight-chain alcohols 

 — ethyl, n-butyl, and to a lesser degree, hexyl alcohol — were good carbon sources. 

 Methyl, rz-propyl and n-amyl alcohols were inadequate for growth, and this was true 

 also for certain alcohols with side-chains (secondary-butyl, tertiary-butyl, wo-amyl, etc.). 

 Furthermore, these nonutilizable alcohols produced significant inhibition of growth 

 when mixed with the lUilizable alcohols. 



