USE OF HOMODUPLEX RIBOSOMAL DNA SPACER AMPLIFICATION PRODUCTS AND HETERODUPLEX CROSS-HYBRIDIZATION PRODUCTS IN THE IDENTIFICATION OF SALMONELLA SEROVARS
Ma. Jensen et Rj. Hubner, USE OF HOMODUPLEX RIBOSOMAL DNA SPACER AMPLIFICATION PRODUCTS AND HETERODUPLEX CROSS-HYBRIDIZATION PRODUCTS IN THE IDENTIFICATION OF SALMONELLA SEROVARS, Applied and environmental microbiology, 62(8), 1996, pp. 2741-2746
When the hypervariable 16S-23S intergenic spacer regions found in prok
aryotic ribosomal DNA (rDNA) are amplified from conserved adjacent Seq
uences, homoduplex double-stranded DNA structures and heteroduplex str
uctures containing substantial regions of single-stranded DNA are gene
rated, The electrophoretic separation of these structures results in p
roduct profile patterns, which may be organized into highly correlated
pattern groups of ribosomal spacer and heteroduplex polymorphism (RS/
HP) types, In a test panel of 380 Salmonella strains that were analyze
d by this procedure, 36 unique RS/HP types were observed, Of the 28 se
rovars in the test group, 21 showed single characteristic RS/HP types,
The remaining seven serovars each contained multiple RS/HP types, whi
ch were also unique to individual serovars, Formation of heteroduplex
structures with a substantially reduced electrophoretic mobility was o
bserved in 29 of the 36 RS/HP pattern types, Because the mobility of t
hese heteroduplex structures is sensitive to intergenic spacer sequenc
e composition, the presence of these structures adds an additional dia
gnostic feature that is extremely useful in the differentiation of Sal
monella serovars, The RS/HP types show sufficient diversity to be usef
ul in the identification of many commonly observed Salmonella serovars
, This analytical procedure is simple to perform and is well suited to
rapid and inexpensive screening of large numbers of Salmonella strain
s.