Differentiation of Frankia strains by their electrophoretic patterns of intracellular esterases and aminopeptidases

Abstract

The closely related Frankia strains BR, S21 and Thr, isolated from the genus Casuarina, Allo2 and Dec from the genus Allocasuarina, and G80 from the genus Gymnostoma, could be distinguished by their esterase zymograms after ultra-low gelling point agarose-polyacrylamide electrophoresis. The kanamycin-resistant derivatives S21-kR and BR-kR could also be differentiated from their kanamycin-sensitive parental strains. Different patterns of intracellular esterases could be obtained by using β-naphthyl propionate or 3-indoxyl acetate as substrates. The substrate 5-bromo-4-chloro-3-indoxyl acetate proved particularly useful, revealing a variety of esterases from Gymnostoma isolates. Zymograms of aminopeptidases from all strains were found to be quite similar. Nevertheless, they allowed differentiation of Frankia strains BR and S21 from their kanamycin-resistant derivatives. Aminopeptidase and esterase zymograms obtained from Gymnostoma isolates were markedly different from all others. Zymograms of esterases and aminopeptidases may prove useful for the identification of some other Frankia strains.