Some Biochemical Differences 437 



marked differences among the chromatographic patterns of 

 extracts of marine and fresh water strains. All studies of this 

 kind were done with stationary phase populations grown in 100 

 ml batches of medium; organisms from continuous culture were 

 not used since the phase of growth is known to influence the 

 character of the extracts (e.g., 5). Such cultures yielded live cells 

 equivalent to 30 to 50 mg dry wt. organisms. Lots of fresh cells 

 equivalent to 10 mg dry wt. were extracted by suspending in 10 

 per cent acetic acid, the cells centrifuged off, and the whole ex- 

 tracts dried onto paper. They were then chromatographed in a 

 conventional manner in two dimensions using phenol and bu- 

 tanol/ammonia. The patterns obtained are illustrated in Figure 

 5, which consists of sketches of tracings of the actual chromat- 

 ograms. Individual strains showed reasonable consistency when 

 extracted and chromatographed a second time, but the differences 

 between sti'ains were wide and suggested that a diagnostic test 

 on these lines might be difficult to develop. Most marked, how- 

 ever, was the qualitative observation that the salt water strains 

 released relatively large amounts of material containing at least 

 5 components, and the fresh water strains released less material 

 with fewer components; sketches of chromatograms from another 

 salt water strain (Canet 41, NCIB 8393) another fresh water 

 strain (Essex 6, NCIB 8307) are included in Figure 5. This figure 

 also includes patterns obtained with salt and fresh water strains 

 trained to the alternative environment; the fresh water strain 

 took on some of the characters of the salt water strain on acclima- 

 tization to the appropriate medium, but the reverse change did 

 not occur. 



Table 3 shows that the qualitative impression that salt water 

 strains released none of such material was correct. In these experi- 

 ments the material was released with 10 per cent acetic acid 

 and analysed for free primary amino-groups by the method of 

 Frame, Russell & Wilhelmi (7). The standard for this assay was 

 Difco "Casamino-acids"; 1 unit is an amount of material giving 

 a colour equivalent to 1 /'g "Casamino-acids" (c ]0% N). 



The nature of the material released from these strains was 

 not studied further. None of tlie spots corresponded to known 

 amino-acids and it is likely tliat they were peptide in nature. 



