Physiological responses induced in bacteria adhering to surfaces

In an attempt to demonstrate a wide range of physiological responses in bacteria attached to surfaces, transposon mutagenesis has been employed to insert into appropriate recipient bacteria a marker gene that lacks its own promoter element. If a suitable target gene is “switched on”; at a surface, then expression of the marker gene should be observed only with growth in the presence of a surface, not in liquid or on agar media. Using Escherichia coli C600 (pRK.2013:: mini‐MuTet^r lacZ) as donor organism and either of the marine bacteria Deleya marina (Rif') or Pseudomonas S9 (Sm^r) as recipients, transposition mutants have been selected, on agar media containing appropriate antibiotics plus X‐gal, that either do or do not express β‐galactosidase. Tests on a large number of Lac”; phenotypes (when grown on agar) have revealed a mutant in which the lacZ gene is “switched on”; only at a surface: These studies will be extended to determine which target genes are affected and the mechanism(s) of the switching process.

Key words:

• Surface responses
• Transposon mutagenesis
• lacZ marker gene
• Marine bacteria
• Adhesion