+ Université Libre de Bruxelles

 

Brussels, February ¢Ist I955

FacuLTé p= MEDECINE ET DE PHARMACIE
115, Boulevard de Waterloo

Service : oe DP 9 RO COL esse TUNG...

see Laboratoire..de..bacteriologrie

Dear Dr. Ledebers,

To-day I send you some of the reprints you request

As for your questions:

I) Do I know of any situations in bacteria analoge
fous to the "nother-daushter" cell differenciation in tuber-
cle bacilli? - No- But until now, I have examined tubercle
bacilli only with the electron microscone. Mowever, i showed
that staphylococci and colibaciilli also divide and lyse in
the nresence of inhibiting concentrations of strentonyg#in.

yw ¢ zNIy

2) Mave I further evidence of this ("mother—daushs
ser" cell diffrentiation) débservation? ~ No.

3) Mow many divisions does the "mother ceil" under.
fo in the presence of the streptomycin? —- If the concentra-
tion of streptomycin is much higher than the minimum batée-
riostatic concentration, the cells seem to divide once only,
Since their number exactly doubles; then they stop dividing
and @& half of the cells show signs of lysis (which half?
mother cells? daughter cells?). 4f the concentration of
streptomycin is lower, but still inhibitory, the cells divie
de once, and then half of them divide a second time: but
which half? the "mother celis" or the "daushter cells"? T
cannot decide at nresent. Malf of the cells again show sirens
of lysis. - After longer incubation withpither concentration
of streptomycin, intact cells also besin to lyse.

 
. Université Libre de Bruxelles

 

FacutTé pe MEDECINE ET DE PHARMACIE
115, Boulevard de Waterloo

2
Of course, it is unnecessary to stress that the dis-
tinction between "mother" and "daughter" celis is just a hppg—-
shesis: my observations fit in with it (differences in frobho-
logy of cells attached one to the other in pairs seening to
result from a second division). Can you think of another expla-
nation?
Yours sincerely,

Dr. Roser ins