Relationship between genotype and phenotype of flagellin C in Salmonella

Abstract

Aim: To discover the relationship between the genotype and antigen serotype of flagellin C among Salmonella strains.

Methods: Fragment of Salmonella flagellin C in plasmid pLS408 was cloned, sequenced and compared with the corresponding sequence in other strains. Salmonella strains including two typhi strains, one paratyphoid strain, one enteritidis and one typhimurium strain were isolated from outpatients. Genome DNA was purified respectively from these clinical isolates, then the corresponding flagellin C fragment was amplified by polymerase chain reaction,and the amplification products were analyzed by agarose gel electrophoresis.

Results: The cloned fragment includes 582 nucleotides encoding the variable region and partial conservative region of Salmonella flagellin C in plasmid pLS408. With comparison to the corresponding sequences reported previously, there is only a little difference from other strains with the same flagellar serotype in both nucleotide and amino acid level. Specific PCR products were amplified in Salmonella strains with flagellar serotype H-1-d including S. muenchen, typhi and typhimurium, but not in S. paratyphoid C or S. enteritidis strains.

Conclusion: In this experiment, the specificity of nucleotide sequence could be found in flagellin C central variable regions as it exists in flagellar serotypes in Salmonella. It may be helpful to developing a rapid, sensitive, accurate and PCR-based method to detect Salmonella strains with serotype H-1-d.

Figure 1

Map of pLS408 (left) and gel electrophoresis of PCR product (right). Lane 1: 100 bp DNA ladder, lane 2: PCR product of partial flagellin C gene, lane 3: PCR product of flagellin C gene.

Figure 2

Comparison of nucleotide sequence between PCR product and the corresponding sequence reported previously (all differences are shadowed or dashed）. *Sequence of partial flagellin C PCR product, #Sequence from Genbank X03395

Figure 3

Comparison of amino acid sequences among different strains with (all differences are shadowed). ^*Amino acid sequence of PCR product. ^#The corresponding sequences of S. muenchen (Genbank X03395). &The corresponding sequence of S. typhi (Genbank L21912)

Figure 4

Amplification of flagellin C gene fragment in different Salmonella strains. Lane 1: S. enteritis; 2, 4: S. typhi; 3: PCR DNA marker; 5: 100 bp DNA ladder; 6: S. typhimurium; 7: S. muenchen (plasmid pLS408); 8: S. typhoid.