Molecular characterization of the groundwater bacterium ABS10

A Gram-negative pleomorphic bacterium, designated ABSIO, pre dominating in a pristine aquifer in Ada, Oklahoma, was selected for characterization and potential as a candidate for the introduction of catabolic genes into a groundwater microbial population. This organism was originally identified as an aberrant Arthrobacter sp. and extensive characterization of the isolate was undertaken to further develop the strain for groundwater microbiological research. The fatty acid methyl ester profile of ABSIO revealed a high percentage similarity value with Pseudomonas putida. Ketodeoxyoctonic acid (KDO) extraction of ABSIO lipopolysaccharide indicates that the KDO of ABSIO is present and modified, possibly due to phosphorylation. DNA:DNA colony hybridization, dot blot and Southern blot analysis showed ABSIO to share a great deal of genetic homology with P. putida. The 16S rRNA sequencing indicated that ABSIO groups with the Gamma division of the purple photosynthetic bacteria. The broad host range plasmid RP4 was introduced into ABSIO and stably maintained indicating that RP4 may serve as a vehicle for introducing catabolic genes into this organism and, hence, into the groundwater microbial community.