title: Identification of genes associated with copper tolerance in an adhesion-defective mutant of Aeromonas veronii biovar sobria.
abstract: TnphoA mutagenesis was used to identify adhesins of Aeromonas veronii biovar sobria 3767, a strain isolated from a diarrhoeal stool specimen. Six mutants, from a library of 154, exhibited significantly reduced levels of adhesion to HEp-2 cells. Primers to the terminal regions of TnphoA were used for inverse PCR and the product from one mutant was cloned into pBluescript and partial sequence data obtained. Scanning GenBank and EMBL data bases revealed DNA sequence similarity to the copA gene of Pseudomonas syringae pv. tomato which confers resistance to copper and other heavy metals. The transposon was located within the copA gene and the mutant exhibited a reduced tolerance to copper. Primer walking, using the inverse PCR product as a template, revealed three open reading frames (ORFs) copA, B and C in A. veronii biovar sobria 3767. The predicted amino acid sequences of ORFs A and B had significant homology (55 and 34% respectively) to the copA and B proteins of P. syringae. No amino acid or DNA sequence homology existed between ORF C of strain 3767 and any other gene in the data bases scanned. Further analysis of the nucleotide sequence failed to reveal the presence of typical copper regulatory genes within the vicinity of the Aeromonas sequence. The association between copper tolerance and adhesion in A. veronii biovar sobria requires further study.
authors.affiliation: Departent of Microbiology, The University of Western Australia, Queen Elizabeth II Medical Center, Nedlands, Australia.
authors.forename: K T
authors.initials: KT
authors.lastname: Francki
authors.forename: B J
authors.initials: BJ
authors.lastname: Chang
authors.forename: B J
authors.initials: BJ
authors.lastname: Mee
authors.forename: P J
authors.initials: PJ
authors.lastname: Collignon
authors.forename: V
authors.initials: V
authors.lastname: Susai
authors.forename: P K
authors.initials: PK
authors.lastname: Keese
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics*; D000333:Aeromonas / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology*; D027682:Cation Transport Proteins; D002460:Cell Line; D003300:Copper / Q000494:pharmacology*; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics; D015723:Gene Library; D006801:Humans; D016254:Mutagenesis, Insertional; D016366:Open Reading Frames; D016133:Polymerase Chain Reaction; D011549:Pseudomonas / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D027682:Cation Transport Proteins; C071263:CopA protein, Bacteria; C071265:CopC protein, Bacteria; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D003300:Copper