Analysis of the Genetic Determinants of Yersiniachelin Siderophore of <i>Yersinia</i>

Abstract

The study is focused on the genetic determinants of the yersiniachelin (Ych) siderophore encoded by the ysu gene cluster and found only in Yersinia pestis and Yersinia pseudotuberculosis. The aim of the investigation was to analyze the genes encoding the biosynthesis of Ych and to assess the possibility of their use for intraspecies differentiation of Yersinia. Materials and methods. The study used complete nucleotide sequences of 583 Y. pestis strains and 300 Y. pseudotuberculosis strains from the NCBI database, as well as 38 Y. pestis and 88 Y. pseudotuberculosis strains from culture collection at the Rostov-on-Don Anti-Plague Institute of the Rospotrebnadzor. The genomes were analyzed using bioinformatics methods and PCR in silico and in vitro. Results and discussion. A comparison of the ysu cluster genes in two Yersinia species has revealed their high conservatism in the plague microbe, while differences in the structure of the transcription terminator of the Ych biosynthesis genes have been found in the pseudotuberculosis microbe. It turned out that the terminator contains nucleotide tandem repeats that differ in the number in different groups of Y. pseudotuberculosis strains, thus indicating their potential use for intraspecies differentiation of these bacteria. To assess the effect of the transcription terminator structure on the Ych expression by plague and pseudotuberculosis microbes, two recombinant plasmids containing PCR copies of Ych biosynthesis operons from Y. pestis KIM and Y. pseudotuberculosis YPIII have been constructed. The introduction of both plasmids into the Escherichia coli H1884 strain, devoid of its own siderophores, has demonstrated that the operon of the YPIII strain determines a significantly higher expression of Ych than that of the KIM strain. The results of the study show that the structure of the transcription terminator of the Ych biosynthesis operon has a considerable impact on the expression of this siderophore and can be used for intraspecies differentiation of Y. pseudotuberculosis strains during epidemiological monitoring.

Keywords

• y. pestis
• y. pseudotuberculosis
• yersiniachelin
• siderophore