STRUCTURAL AND SEGREGATIONAL STABILITY OF VARIOUS REPLICONS IN ACTINOBACILLUS-ACTINOMYCETEMCOMITANS

Few vectors suitable for cloning in Actinobacillus actinomycetemcomita ns, a periodontal pathogen, have been described. These plasmids were b ased either on the native A. actinomycetemcomitans replicon, pVT736-1, or derivatives of the IncP and IncQ family of plasmids. Their usefuln ess as cloning vectors is limited because of instability or size. Ther efore, the ability of additional replicons to function in A. actinomyc etemcomitans was evaluated. Derivatives of p15A, ColE1/ fl, and pWV01 transformed A. actinomycetemcomitans efficiently and exhibited no stru ctural instability in the new host. The stable maintenance of A. actin omycetemcomitans-specific DNA fragments inserted into the p15A derivat ive, pDMG4, demonstrated the ability of this plasmid to function as a cloning vector. In addition, pVT736-1 was used to clone selectable mar kers directly into A. actinomycetemcomitans. These constructs were str ucturally and segregationally stable. (C) 1996 Academic Press, Inc.