no yield of ssDNA with helper phage vcsm13 and M13KO7

Cornelius Krasel krasel at
Tue Oct 6 12:37:52 EST 1998

Frank Riffer <fr at> wrote:
> For ssDNA preparation I infected E. coli cells CJ236 carrying phagemid with
> helper phage, using vcsm13 and m13KO7 which carry a kanamycin resistence
> gene. After infection cells behave kanamycin resistant but no extrusion of
> phage particles occurs.I tried multiplicitites of infection (m.o.i) of 1,
> 10,  20  and 50.
> Can someone help me ?

Are your CJ236 still chloramphenicol-resistant? Otherwise, they may have
lost the F plasmid which is essential for M13 infection.


/* Cornelius Krasel, U Wuerzburg, Dept. of Pharmacology, Versbacher Str. 9 */
/* D-97078 Wuerzburg, Germany   email: phak004 at  SP4 */
/* "Science is the game we play with God to find out what His rules are."  */

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