%0 Journal Article %A Taylor, Victoria L. %A Titball, Richard W. %A Oyston, Petra C. F. %T Oral immunization with a dam mutant of Yersinia pseudotuberculosis protects against plague %D 2005 %J Microbiology, %V 151 %N 6 %P 1919-1926 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.27959-0 %K i.v., intravenous(ly) %K s.c., subcutaneous(ly) %K MLD, median lethal dose %K 2-AP, 2-aminopurine %I Microbiology Society, %X Inactivation of the gene encoding DNA adenine methylase (dam) has been shown to attenuate some pathogens such as Salmonella enterica serovar Typhimurium and is a lethal mutation in others such as Yersinia pseudotuberculosis strain YPIII. In this study the dam methylase gene in Yersinia pseudotuberculosis strain IP32953 was inactivated. Unlike the wild-type, DNA isolated from the mutant could be digested with MboI, which is consistent with an altered pattern of DNA methylation. The mutant was sensitive to bile salts but not to 2-aminopurine. The effect of dam inactivation on gene expression was examined using a DNA microarray. In BALB/c mice inoculated orally or intravenously with the dam mutant, the median lethal dose (MLD) was at least 106-fold higher than the MLD of the wild-type. BALB/c mice inoculated with the mutant were protected against a subcutaneous challenge with 100 MLDs of Yersinia pestis strain GB and an intravenous challenge with 300 MLDs of Y. pseudotuberculosis IP32953. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.27959-0