BACTERIOCIN SMALL OF RHIZOBIUM-LEGUMINOSARIUM BELONGS TO THE CLASS OFN-ACYL-1-HOMOSERINE LACTONE MOLECULES, KNOWN AS AUTOINDUCERS AND AS QUORUM SENSING CO-TRANSCRIPTION FACTORS

small bacteriocin was isolated from the culture broth of the gram-nega tive bacterium Rhizobium leguminosarum, which forms symbiotic nitrogen -fixing root nodules on a number of leguminous plants, The structure o f the molecule was elucidated by spectroscopic methods and identified as N-(3R-hydroxy-7-cis-tetradecanoyl)-L-homoserine lactone, The absolu te configuration of both asymmetric carbon atoms in the molecule was d etermined by the use of the chiral solvating agents S-(+)- and R-(-)-2 ,2,2-trifluoro-1-(9-anthryl)-ethanol. small bacteriocin is structurall y related to the quorum sensing co-transcription factors for genes fro m other bacteria such as Vibrio fischeri, Pseudomonas aeruginosa, Erwi nia carotovora, and Agrobacterium tumefaciens which are involved in an imal-microbe or plant-microbe interactions. The mechanism of regulatio n of such interactions by this kind of co-transcription factors is sti ll unknown in R. leguminosarum.