help asked on M13 subcloning of cosmids

[Nancy Terryn]

Dear ara-netters

we are sequencing in our lab parts of the Arabidopsis genome. Therefor we 
are subcloning cosmids into the M13 vector by sonicating the cosmids and 
cloning 800-1700 bp, endrepaired, into M13 SmaI cut and cipped. As a 
control we use Lambda aluI fragments. Lately we are having some problems 
to get high efficiency cloning of our sonicated fragments in M13.
The controls all seem to look OK. So it is most likely the insert.
Does anybody out there has some advice for us? I heard of an instrument 
called the "nebulisizer"(??) that would be better then sonicating because
it does not damage the ends so much. Anybody has experience with that?

Thanks for any suggestions!!

Nancy Terryn
Lab of Genetics
K.L. Ledegankcstraat 35
9000 Gent/ Belgium

Tel 32 9 264 50 10
Fax 32 9 264 53 49