cell clumping after electroporation

[FABIAN MOEBIUS]

Various people in our lab now experience with different types of frozen competent cells that 
after electroporation and 1 hour growth at 37 degres the cells are 
not homogenous but show sticky filaments as seen with precipitated high 
molecular weight DNA (looks like alien worms). Did anybody experience this before? We suspect 
that this must be a problem of cuvettes, medium added after EP or 
eprouvettes used for incubating the cells before plating.
Thanks for any hint
Dr. Fabian F. MOEBIUS
Institut fuer Biochemische Pharmakologie
Peter Mayr Str. 1
6020 Innsbruck
AUSTRIA
TEL ++43-512-507-3155
FAX ++43-512-588627