25 research outputs found
Characterization of outer membrane proteins of <i>Yersinia pestis </i>and <i>Yersinia pseudotuberculosis </i>strains isolated from India
508-514The majority of virulence factors including
the 12 Yersinia outer membrane proteins (Yops), 29 Yop secretion
proteins (Ysc) and few specific Yop chaperone (Syc) are contributed by the 70
kb LCR middle plasmid of Yersinia pestis. Yersinia pestis isolates
recovered during 1994 plague outbreak and rodent surveillance samples of Southern
states of India were studied for the presence of important Yops by the conventional
procedure of partially purifying outer membrane proteins (Omps) after
cultivation in calcium deficient media. Prominent bands numbering 4-5 between 34-42
kDa region corresponding to important Yops were seen in all the isolates as
well as in other Yersinia and non-Yersinia species by SDSPAGE. Western
blotting with the polyclonal antisera raised against these Omp preparations
revealed few immuno-reactive band, that appeared to be shared among Y.
pestis, Y. pseudotuberculosis, Y. enterocolitica, Y. fredrocksenĂĽ, Y. Intermedia,
Y. kristensenĂĽ and E. coli. Three recombinant Yap proteins namely, YopM, YopB and LcrV were produced and
antisera to these proteins could reveal presence of these Yops in the Y. pestis
Omp preparations. In order to further characterize the important Yops among
Omps, attempts were made to generate monoclonal antibodies against Omp
preparation. Three of the 4 stable reactive clones that were obtained, when
tested, had extensive cross-reactions among pathogenic Yersinia species,
Y. pestis and Y. pseudotuberculosis isolates, other Yersinia species and the members
of Enterobacteriaceae in dot-ELISA and Western blotting. One of the
monoclonal antibodies, YP1, exhibited reaction to all the pathogenic Yersinia
species and the isolates, with restricted cross-reactivity to Y. intermedia,
Y. kristensenii, K. pneumoniae. None of the 4 monoclonal antibodies had
reactions with the 3 recombinant Yop proteins. It appears that under low
calcium response, the Y. pestis not only activates secretion of Yops but
also a large number of other proteins, which as per the present observations
are cross-reactive within the family Enterobacteriaceae.</i