First of all congratulations to the chairmanship at Stanford. With you, Kornberg and Yanofsky it's quite a place! The
meeting in Chicago was a success (although we missed you). There were no 'meatheads' talking for 1 hr about irrelevant
things. All the talks were intense and concentrated. During the transition period here I must get my own work (plus some of
Kiyoshi's unpubl. obs.) published. The article will be rather long and in a way dull because it stresses method. As you
already know the results became much clearer after I dumped glucose out of the window (that is an exaggeration because you
can't open windows in the clinical center!) The log phase's generation time with glycerol as carbon source is of course
much longer and I lost a good deal of my night sleep - - but it was worth it. I may have told you that galactose in conc.
of 1 times 10^-5 mol has a bacteriostatic effect on the growth of 3096 (transferase-less) which is quite dramatic (this is
w. glycerol instead of gluc. as C source). After 14-18 hrs a "recovery" sets in which may be selection of mutants.
Yet these suspected mutants are still Gal neg. The analysis of this phenomenon is first on the program. Likewise, I am curious
to know the effect of galactose on 3096 on the burst size if infected with virulent lambda. Another new observation: 4-epimerase
is 10-20 times higher in the presence as in the absence of galactose in 3100, 3096, 3092 - - again provided glycerol is the
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This is of course not surprising at all. In "Gal 3" (3264 and 3265) in the constitution 4-epim. is about 50% (i.e.
app. same order of magnitude) as that found in 3100 and 3096. However, add. of galactose in "Gal 3" does not give
10-15 times increase but only 50-75% of an increase (which may be within the limit of error*). "Gal 9" is of course
complete devoid of 4-epimerase, const. as well as induc. The kinetics of galactosidase is also intriguing. In 3096 as follows:
I suspect that in 3096 the gal kin. is almost operating as fast as gal pronease[?] and hence the conc. of free gal in the
cell very low, sufficient to induce gal kin. but insuff. to induce galactosidase until the acc. of gal-1-P (which is staggering)
begins to inhib. the phosphorylation of gal and hence permit the free gal in the cell to attain higher values. This is born
out of the fact that in 3100 and 3092 galactosidase increases (on a cellular basis) rapidly right from the begining [sic].
More detailed and precise information later. Phenol extraction of complex polysach. (cell wall, somatic etc) showed no galactose
(if any merely traces) which agrees with the fact that 3099 grows happily on glycerol without gal. I am interested in marrying
off 3099 with a Shigella. Perhaps Yanofsky's deletion mutants will also be helpful.
I am tired by now, will finish with lots of greeting to you and Esther.
*We have found for instance that 4-epimerase conc. is going down to 30-40% in post-log phase as compared with the titer in
the middle log phase.