So J. T. HOLDEN 
amounts of proline, but when the extracellular osmotic strength is increased materially, 
proline or a mixture of amino acids can be accumulated to levels as high as those 
found in gram-positive bacteria. It is clear that while the native pool in E. coli is 
distinctly lower than the comparable pool in gram-positive organisms, this bacterium 
has the ability to retain very large pools under favorable osmotic conditions. The 
relation between extracellular osmotic strength and intracellular accumulation of 
single amino acids is discussed in detail elsewhere in this volume (HOLDEN, BRITTEN). 
Table V summarizes results for the tubercle bacillus, Corynebacterium, and related 
organisms. Mycobacterium tuberculosis has been studied extensively and found to 
contain a diversified pool whose composition varies with age. In the two studies 
cited cells were cultured under closely similar conditions, but the qualitative com- 
ABER IV 
POOL CAPACITY FOR EXOGENOUSLY SUPPLIED AMINO ACIDS 

Intracellular 


2 Extracellular level 
DUES: amino acid (umoles|/Too mg Ref. ‘numbers 
dry wt.) 
Staphylococcus aureus Glutamic acid 18-54 59 
Streptococcus faecalis Glutamic acid 45 87 
Lactobacillus avabinosus Glutamic acid 50-95 84 
Escherichia coh Proline 2-24 Dit 7} 
Escherichia coli (+ sucrose) Proline or amino 100 23 
acid mix 

position found differs markedly. The results of another study”: % disagree with the 
two examples shown. When cultured in an amino acid containing medium, Coryne- 
bactertum diphtheriae contains a remarkably varied pool including hydroxylysine 
which is an infrequently encountered constituent of microbial pools. Work’s investiga- 
tion'’® was one of the first complete pool studies to follow GALE’s reports and resulted 
in the detection of an unknown which was subsequently isolated and identified by 
Work as diaminopimelic acid!8*; 19°, This is one of the few examples in which chro- 
matographic study of a microbial pool has revealed the existence of unusual compo- 
nents whose further investigation has provided insight to new metabolic pathways, 
in this case cell wall composition and synthesis (cf. WorK!!, SALTON?®*). BLASS AND 
MACHEBOEUF® independently encountered an unknown in Vzbrio chlolera which they 
subsequently recognized to be diaminopimelic acid!* following Work’s identification 
of this substance. The PW-8 strain of C. dzphtheriae also has been studied by ISKIERKO* 
who found it to have a pool composition materially different from that reported by 
Work. As indicated previously, this situation recurs with all classes of organisms and 
illustrates the sensitivity to change of microbial amino acid pools. The Actinomyces 
pool (Table V) also has a diversified composition even when the organism is cultured 
with an inorganic nitrogen source. On the other hand, another report on A. violaceus 
shows a more limited pool composition. The taxonomically related organism Nocardia 
rugosa has a distinctly restricted pool. 
References p. 105/108 
