Journal of Undergraduate Research


Yersinia pseudotuberculosis, biofilm formation, global regulator CsrA


Life Sciences


Microbiology and Molecular Biology


The bacteria Yersinia pestis is the causative agent of bubonic plague, and its ability to form biofilm in fleas is essential for plague transmission by fleas [1]. Y. pestis recently evolved from Y. pseudotuberculosis (Y. pstb), and the two have nearly identical genomes. Y. pestis forms a biofilm in fleas that is capable of blocking the flea’s feeding. These biofilms are made up of a community of bacteria adhering to a polysaccharide matrix that is made by the hmsHFRS gene products. Y. pstb is capable of infecting fleas, but will not block the flea’s feeding [1]. Since the hmsHFRS genes themselves are identical, this suggests that Y. pstb has regulatory elements that function differently from those of Y. pestis [2]. Although the hms genes in these two bacteria likely differ in regulation only, there may be other exopolysaccharide producing genes that may account for different biofilm properties. Understanding the manner in which biofilm is regulated in Y. pstb will aid in understanding the regulation of biofilm in Y. pestis and the manner in which they have evolved the ability to be transmitted through fleas.

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