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Appl. Environ. Microbiol., 04 1997, 1406-1420, Vol 63, No. 4
D Cue, H Lam, RL Dillingham, RS Hanson and MC Flickinger
We report the fist genetic transformation system, shuttle vectors, and
integrative vectors for the thermotolerant, methylotrophic bacterium
Bacillus methanolicus. By using a polyethylene glycol-mediated
transformation procedure, we have successfully transformed B. methanolicus
with both integrative and multicopy plasmids. For plasmids with a single
BmeTI recognition site, dam methylation of plasmid DNA (in vivo or in
vitro) was found to enhance transformation efficiency from 7- to 11-fold.
Two low-copy-number Escherichia coli-B, methanolicus shuttle plasmids,
pDQ507 and pDQ508, are described. pDQ508 caries the replication origin
cloned from a 17-kb endogenous B. methanolicus plasmid, pBM1. pDQ507
carries a cloned B. methanolicus DNA fragment, pmr-1, possibly of
chromosomal origin, that supports maintenance of pDQ507 as a circular,
extrachromosomal DNA molecule. Deletion analysis of pDQ507 indicated two
regions required for replication, i.e., a 90-bp AT-rich segment containing
a 46-bp imperfect, inverted repeat sequence and a second region 65%
homologous to the B. subtilis dpp operon. We also evaluated two E. coli-B.
subtilis vectors, pEN1 and pHP13, for use as E. coli-B. methanolicus
shuttle vectors. The plasmids pHP13, pDQ507, and pDQ508 were
segregationally and structurally stable in B. methanolicus for greater than
60 generations of growth under nonselective conditions; pEN1 was
segregationally unstable. Single-stranded plasmid DNA was detected in B.
methanolicus transformants carrying either pEN1, pHP13, or pDQ508,
suggesting that pDQ508, like the B. subtilis plasmids, is replicated by a
rolling-circle mechanism. These studies provide the basic tools for the
genetic manipulation of B. methanolicus.
Copyright © 1997, American Society for Microbiology
Genetic manipulation of Bacillus methanolicus, a gram-positive, thermotolerant methylotroph
Biological Process Technology Institute, University of Minnesota, St. Paul 55108, USA.
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