February 19, 1948 ‘ ee Thanks very such for sending me your listing of lyophilized W- coli ‘ :* oultares. It cheoks all right with mine, but I wasn't too confident of vv» Ate (The confusion about W-169 and W-172 arises because I was growing “vs those stocks at the same tims I was preparing cultures to send you,’ _- Monod, and Kauffmann. Monod now has Y-&0, Y-53, 58-161, Y87, Y-10, K-12 7 - and several W's, Kauffmann has K-12, Y40 and Y53, on which I have asked -. - . - him te do a serologigal typ (v. his review in the Dec? J. Immunol.) . ,.. In addition, 1.8.Stone (Texas) has asked for and been sent Y¥53, Y40, . Y87 and Y-l0. If you don't have W-169 and W-172, they were probably sent | to Monod by mistake, and I shall have to write him. They are interesting because on first test 169 was a non-fermenting mtant (generally) while _172 was gluconic-, maltose and lactose/. Ss . neg o> Il finally found that vial of DRNase at the bottom of a pile of junk _. rvs and am sending same. I haven't’done any further transform expts. waiting #0 hear ‘some details (in particular which mutant you used) about your . °° _ expts, with Beam. I think this is one case where dgplication is more efficient. .. that dddependence. a . yo “Dr. Led. Cole, the retired chief of our department died Tuesday afternoon ~~. after a lingering Ulinesa. In every way this was his personal department ao until he retired, since he built it up almost singlehanded in the azrly >. days. You gay have known him when you were here, a o> +2 The count of Lac stant types 1s now eight. Lac,- is by all odds the _ ,f08t frequently occurring antation for lactose-negativity, which accounts for the first two isolated (¥-87 and ¥53) being the same. Most of the mtants are specific for b-galactosides, although Lac,—- is Lac— b-gal./, except fpr a third allele in W-128 which is Lae-bgal.— . Some of the mutants are however * non-specific, but with fantastic patterns of utilization. 2.4, 172 (which was not yet analysed for single-gene-mutation). Further ex: 108 which is Glu-Gal/Lac~Mal-. In this stock you can get either reverse mutation to wild type, or as in W~117, mtation of a suppressor gene which makes it Glu/ Gal /Mal~Lac-. In W-117, autants can be found which are kacfMlal-, but I’ te. . , don't know yet what gene mutates there. Here, I think it will be very difficult “<%, +>... dndeed.to construct a system baded one ‘leg lgene:1 enzyme. Monod writes woo, J). 4 fhatehe can isolate a lactase from ®,’coli ML which is a simple hydrolase, | __ voy sy Ut-ds found anly in lactose-adapated, lactose‘ cells. fnpther complex-pheno- - _- ype (single-locus) mutantsis W-145 which is Lac-Mal-Gna(gluconis)-Gluf. he ee wg tae AEP ae Ble ee Coa oe, - Sy other 6 are specific.:: eg x -“Xtve had some trouble keeping stocks because my refrigerator hasn't arrived yet, and my cold space is very limited. I am embarragsed, anyhow, to have to ~ / ask for W-42 and W-43 whigh have conked out on me. As an ximke alternative, © perhaps it would be a good ddea if you could send ge one complete set of the lyophilled tubes of Womutants which would leave you with two for security. .. Before too long, 1 hope to have a lyophil apparatus set up here, and the cold. oe produced, we are not necessarily any closer to seeing how a gene is working. ' try to do some similar experiments, looking for serologically detectable copies | : “Cer bovine sperm. Much hangs on confirmation of Emerson's experinents, concerbing | Poe v Which I, and a lot of other people, have, of course very grave doubts. Sometime, — RS maybe, Irwin ‘and I will try to go over it, fe . ; ee ‘I have to send my manuscript of "Problems..." back to Darlington in a few days along with a statement of how many reprin&s should be ordered. Darlington simply states that the cost will be about 25% more than it would be in the US _ due to exchange differentials. I've put in so much time on it here that I propose . | to send it in as a joint contribution from OBL and Wis. Is this agreeablé to you? You know how long its is: about 70 pages of typescript. Can you give me any -- notion of whether. OBL would like to have copies, and how many, and whether _. > @any.can.ob. should be purchased on Childs Fund money.A 10% of hitherto unpublished » . odds and ends are included for the support of which the Childs Fund will be .- “i -aeknowledged. Ag. soon ag Feasible, tr send you a copy of the revsse | manuseript, - & Bast regards, | be -_ "