GENETIC TRANSFORMATION OF STREPTOMYCIN RESISTANCE IN XANTHOMONAS PHASEOLI

Abstract

Transformation of resistance to antibiotics was observed in Diplococcus pneumoniae by Hotchkiss (1951, 1952a, 1952b) and in Haemophilus influenzae by Alexander and Leidy (1953) and Alexander et al. (1954). In all these species only certain strains were capable of being transformed. The ability to be transformed has been termed competence; refractory strains are not competent. Austrian (1952) has suggested that the structure of the cell surface determines the competence of pneumococci. This could be considered as strain competence. In Haemophilus influenzae, only a portion of a given population of R cells proved to be competent for transformation. Alexander and Leidy (1951) suggested that such cellular competence may arise by mutations which introduce a specific somatic antigen that functions as a receptor. Alexander et al. (1954) found that the proportion of competent cells varied with the phase of the growth cycle of the recipient population. The fraction of

The Origin of Bacterial Species

“…Transformations were first observed with the pneumococci (7,26), but since that time similar processes have been found to occur among the genera Haemophilus (2), Neisseria (3,15), Agrobacterium (38), Xanthomonas (17), and recently in Bacillus subtilis (78). In a transformation experiment, DNA is extracted from a donor strain genetically marked AbC.... ; an appropriate recipient strain, one marked aBc, is then exposed to the more or less purified donor DNA.…”

Bacteriophage Reactions and Speciation of Phytopathogenic Xanthomonads

“…This result confirms the uniformity observed in the genus Xanthomonas with respect to their nutrition, physiology, and biochemistry (STARR 1946, BU'RKHOLDER and STARR 1948, DYE 1962, DE LEY 1962, STARR and STEPHENS 1964. Computer taxonomy (COLWELL and LISTON 1961a, 1961b, COLWELL and MANDEL 1964 and DNA comparisons (COREY and STARR 1957, MARMUR, FALKOW, and MANDEL 1963, DE LEY and VAN MUYLEM 1963, COLWELL and MANDEL 1964 have likewise confirmed the essential similarity among xanthomonads, irrespective of their species label.…”

Genetic transfer and bacterial taxonomy.

“…A preliminary account has appeared of resemblances based on phage susceptibility as the characters (105), and these resemblances show some correspondence with the resemblances based on other phenotypic characters. Transformation has been reported in this genus (108,109). The organism known as X. uredovorus appears to belong to Erwinia (196, 197, 205, 445) and is included here with the Enterobacteriaceae.…”