Table 1.

Phenotypic Distinctions Between Typical Strains of Yersinia pestis and Yersinia pseudotuberculosis (Brubaker 2004)

Determinant	Y. pestis	Y. pseudotuberculosis	Mutational mechanism or event	Consequence in Y. pestis	Reference
pPCP	+	0	Lateral transfer	Acquisition of plasminogen activator (accelerated dissemination in host tissues and posttranslational degradation of undelivered Yops). Acquisition of pesticin (assures retention of pPCP)	Ben-Gurion and Shafferman 1981, Ferber and Brubaker 1981, Protsenko et al. 1983
pMT	+	0	Lateral transfer	Acquisition of capsular fraction 1 antigen (resistance to phagocytosis). Acquisition of murine toxin (survival in the flea vector and prompt death of murine hosts)	Protsenko et al. 1983, Kutyrev et al. 1986, Protsenko et al. 1991, Hinnebusch et al. 2002
Hms+	+	0	Constitutive expression of hmsT	Ability to colonize and block the flea proventriculus	Jones et al. 1999, Hare and McDonough 1999
Lipopolysaccharide O group structure at 26°C	0	+	Cryptic R genes	Constitutive resistance to complement (alternative pathway)	Skurnik et al. 2000
YadA	0	+	Frame-shift	Minimized association with host cell surfaces	Rosqvist et al. 1988
Host cell invasin (Inv)	0	+	IS1541 insert	Minimized association with host cell surfaces	Simonet et al. 1996
Host cell invasin (Ail)	0	+	IS285 insert	Minimized association with host cell surfaces	Torosian and Zsigray 1966
Glucose 6-phosphate dehydrogenase	0	+	Missense mutation	Loss of hexose monophosphate pathway dictating reversal of transketolase and transaldolase function or reliance on host/flea pentose for synthesis of RNA	Mortlock and Brubaker 1962
Aspartase	0	+	Missense mutation	Stoichiometric conversion of exogenous L-glutamate to L-aspartate with loss of the oxalacetate pool and enhanced requirement for CO2	Dreyfus and Brubaker 1978
Biosynthesis of glycine (or L-threonine)	0a	+	Loss of serine hydroxymethyltransferase activity by regulatory mutation	Elimination of unnecessary function	Burrows and Gillett 1966, Brubaker and Sulen 1971
Biosynthesis of L-phenylalanine	0a	+	Large deletion	Elimination of unnecessary function	Burrows and Gillett 1966
Biosynthesis of L-methionine	0a	+	IS insert	Elimination of unnecessary function	Englesberg and Ingraham 1957, Burrows and Gillett 1966
Fermentation of rhamnose	0a	+	Small deletion	Elimination of unnecessary function	Englesberg 1957
Fermentation of melibiose	0a	+	Single base addition	Elimination of unnecessary function	Pollitzer 1954
Urease	0a	+	Frame-shift (single base addition)	Elimination of unnecessary function	Sebbane et al. 2001
Assimilation of low levels of NH4+ into organic linkage	0a	+	Unknown mechanism	Loss of primary NH+4 pick-up. Elimination of unnecessary function	Brubaker and Sulen 1971
Toxicity of lipid A	0	+	Lack of acetylation	Minimizes inflammation	Kawahara et al. 2002

^aKnown to undergo meiotrophic reversion to the Y. pseudotuberculosis phenotype.