Instability in stock cultures of Erwinia

M. Alexeyev malexeyev at
Wed Jan 24 09:17:13 EST 1996

In article <4e3sr0$q90 at>, hanusj at (Joe Hanus)

> A number of plant pathologists associated with Microbial Germplasm
> Database ( have posed this question.  If
> anyone can help, I'll forward to the interested parties.
> These individuals are having difficulty with stored glycerol stocks of
> softrot Erwinia, specifically Ecc and Eca.  Each researcher uses their
> strains for plant experiments once or so a year and the strains remain
> stored the rest of the year.  This year, after culturing, the strains
> were very weakly pectolytic on CVP and caused some, but less than
> before, maceration in tubers.  I've asked about tuber age and culture
> contamination, but my sleuthing didn't come up with anything that was
> obviously awry.
> Has anyone else encountered this problem?  If so, how common is it to
> observe loss or reduction of pectolytic activity on CVP and maceration
> of potato tubers of Ecc or Eca cultures stored in glycerol at below
> -20 (usually at -70)?  Does anyone know why it happens?  Are there
> other ways to store Ecc or Eca such that pectolytic activity is
> preserved?

I have encountered similar problems when screening Erwinia and
Enterobacter cultures for the presence of restriction endonucleases.
Several strains that had RE activity have lost it after 1 month storage in
a stab at room temp. I would be curious to learn the reason.

M. Alexeyev


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