30 J. A. Bcntlcy 



water showed high activity, with the production of peaks which are 

 possibly zones X and Y (Figure 2C). 



Rechromatography of zone Z (from Figure 2A) in water after 

 bioassay clearly showed two peaks of activity (Figure 2D). If it is 

 assumed that X and Z behave similarly to lAA and IAN respectively 

 on chromatography in the solvents used here, then the peak near the 

 solvent front in Figures 2C and 2D will be X, released from Z, which 

 is running at an Rf of approximately 0.4. 



Treatment of zone X (Figure 2A) with A^" HCl and rechroma- 

 tography in isopropanol-ammonia gave a large peak in zone Z (Fig- 

 ure 2B) and a hint of zone Y, Thus, a mutual interconversion of X 

 and Z has again been demonstrated as in Oscillatoria, and X, Y, and 

 Z appear to be stable to treatment with N HCl. 



The possibility was considered that the active substances wxre not 

 completely separating during chromatography, and that dips in the 

 histograms between peaks of activity might be due to the presence 

 of inhibitors, although true inhibition (below the level of the water 

 controls) is rarely obtained. Frequently, however, bioassay of dilu- 

 tions of the original solutions {e.g., Figures lA and 2A) show the same 

 general pattern of distribution of activity. Inhibitory effects generally 

 disappear very much more quickly on dilution than growth-promot- 

 ing effects, and if an inhibitor had been present at Rj 0.6 to 0.8 in Fig- 

 ure 2A in sufficient quantities to cause a dip in the level of activity, 

 one would expect that bioassay of tenfold dilutions would show 

 over-all activity along the length of the paper from X to Z. This does 

 not happen, and the original promoting peaks are still clearly de- 

 fined. It is thus more than likely that peaks X and Z represent true 

 peaks due to discrete substances. The over-all activity sometimes ob- 

 tained on papers such as those illustrated in Figure 2B and Figure 2C 

 is more likely to be due to the activation of precursors on the paper 

 during the various operations to which it is subjected. Evidence is con- 

 tinually turning up that there are inactive precursors on the papers. 



Ochromonas malhamensis 



The petroleum ether fractions were inactive and were rejected. 

 The acidic ether fractions of both samples contained active substances, 

 which were concentrated in zone Z near the solvent front in the first 

 sample (Figure 3A), but which separated into three well-defined /ones 

 in the second sample (Figures 3B and 3C, zones X, Y and Z). 



Ochrofnonas 1 extracts were chromatographed directly in isopro- 

 panol-ammonia, but Ochromonas 2 fractions were first purified by 

 line-loaded chromatography in water, because of the large amounts 

 of pigments in the extracts. The base line portion where most of the 



