PubMed | Moscow Institute of Physics and Technology, 10State Research Institute of Genetics and Selection of Industrial Microorganisms, 1Research Institute of Genetics and Selection of Industrial Microorganisms Genetika and 4Research Institute of Genetics and Selection of Industrial Microorganisms Genetika
Type: | Journal: Microbiology (Reading, England) | Year: 2016
The lux-operon f the psychrophilic bioluminescent bacterium A. logei is regulated by Quorum Sensing (QS). The key components of this system are LuxI that catalyzes the synthesis of autoinducer (AI) and LuxR that activates the transcription of entire lux-operon. The lux-operon of A. logei contains two copies of luxR gene: luxR1 and luxR2. In the present study lux-operon sequence analysis from 16 strains of A. logei, isolated from cold habitats of the White, Baltic, Okhotsk and Bering Seas was carried out. The phylogenetic analysis showed that all isolated strains of A. logei have both copies of luxR genes which are homologous to luxR genes of relative A. salmonicida. LuxR1 and LuxR2 activity evaluation showed that LuxR2 remain active at significantly lower concentration of AI (10-9M) compared to LuxR1 which is activate only at high AI concentration (10-6). As QS response is already prominent at AI concentrations as low as 10-8 - 10-9M, we conclude that LuxR2 is a main activator of the lux-operon of A. logei. The thermolabilities of LuxR1 and LuxR2 are similar and exceed that of LuxR of mesophilic bacterium A. fischeri. As oppose to LuxR2, LuxR1 is not a substrate of Lon protease and does not require the chaperonin GroEL/ES for its folding.