Further Observations on Genetic Transformation in Pseudomonas

Abstract

S U M M A R Ylntraspecific transformation in three strains of Pseudomonas Jyuorescens was observed with respect to gelatin liquefaction and chlortetracycline resistance. In interspecific transformation experiments involving 23 pairs of strains and four markers, two yielded positive results: a strain of P. Jluorescens acquired the property of gelatin liquefaction when transformed with P. aeruginosa DNA, and a strain of fish Pseudomonas, incapable of growing at 37 "C, did so when transformed with DNA from another strain of P. aeruginosa. The guanine-cytosine content of the DNA of the strains investigated ranged between 61.0 and 64'4mol "/o. The transforming ability of DNA was destroyed by DNase. The divalent ions Mg2+, Ca2-and Ba2--'-improved transformation frequency several fold. Actinomycin D inhibited transformation.

Pseudomonas stutzeri and related species undergo natural transformation

“…There have been reports of natural transformation of chromosomal DNA in P. fluorescens (19,20) and in P. aeruginosa (17,18), but these observations have not been confirmable (5,22,25). Although the transformability of P. solanacearum has been cited (11) it is not clear that the observed phenomenon was not, in fact, conjugation (6).…”