Amino Acids as taxonomic markers in nitrogen fixing bacteria

ABSTRACT

Analysis by TLC of the free amino acids of several nitrogen -fixing bacteria revealed the presence of several unusual amino acids of various distribution in different species. These included acetylornithine, cystathionine, hydroxyglutamic acid, ethylasparagine, dihydroxyproline and the dipeptide, gamma-glutamyl S-methyl cysteine. The results indicate close similarities between the studied rhizobia. The results suggested that both R. trifolii 112; R. phaseoli; and R. sesbaru have a common ancestor. The presence of cystathionine, an unusual non - protein amino acid, in Azotobacter cHroococcutn and Rhizobium phaseoli possibly suggested a phylogenetic relationships between both species. The data obtained indicate the possible use of unusual amino acids for taxonomic revision of the nitrogen fixing bacteria