A CONTINUOUS-CULTURE MODEL TO EXAMINE FACTORS THAT AFFECT TRANSDUCTION AMONG PSEUDOMONAS-AERUGINOSA STRAINS IN FRESH-WATER ENVIRONMENTS

Transduction among Pseudomonas aeruginosa strains was observed in cont inuous cultures operated under environmentally relevant generation tim es, cell densities, and phage-to-bacterium ratios, suggesting its impo rtance as a natural mechanism of gene transfer, Transduction was quant ified by the transfer of the Tra(-)Mob(-) plasmid Rms149 from a plasmi d-bearing strain to an F116 lysogen that served as both the recipient and I reduction in the phenotype of the mock transductant over time, H owever, in experiments in which transduction source of transducing pha ges, In control experiments in which transduction was prevented, there was a was permitted, the proportion of transductants in the populatio n increased over time, These data suggest that transduction can mainta in a phenotype for an extended period of time in a population from whi ch it would which consisted of terms for the selection of the transduc tant's phenotype and for the formation of new otherwise be lost, Chang es in the numbers of transductants were analyzed by a two-part mathema tical model, transductants, Transduction rates ranged from 10(-9) to 1 0(-6) per total viable cell count per ml per generation and increased with both the recipient concentration and the phage-to-bacterium ratio , These observations indicate an increased opportunity for transductio n to occur when the interacting components are in greater abundance.