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Dichelobacter nodosus serotype M fimbrial subunit gene: implications for serological classification
1Animal and Food Sciences Division, Lincoln University, Canterbury, New Zealand.
Veterinary Microbiology
|March 27, 2001
Summary
Investigating the Dichelobacter nodosus fimA gene in serotype M strains revealed sequence differences. Standard primers failed, necessitating a modified approach to amplify and sequence the gene, uncovering novel genetic variations.
Area of Science:
- Bacteriology
- Molecular Biology
- Genetics
Background:
- Dichelobacter nodosus causes significant economic losses in livestock, primarily through footrot.
- Fimbrial subunit gene A (fimA) is a key virulence factor and basis for serotyping D. nodosus.
- Previous studies relied on conserved regions for fimA amplification, potentially missing strain-specific variations.
Purpose of the Study:
- To investigate the fimA gene sequence of a Dichelobacter nodosus serotype M strain (M-SPAHL).
- To evaluate the efficacy of existing primer sets for amplifying fimA from diverse D. nodosus serotypes.
- To characterize the genetic relatedness of the M-SPAHL fimA to other known D. nodosus strains.
Main Methods:
- Attempted amplification of the D. nodosus fimA gene using a primer set designed for Nepalese serogroup M isolates.
- Modified primer set by substituting the downstream primer with one specific to other D. nodosus serogroups.
- Cloned and sequenced the amplified fimA gene from the M-SPAHL strain.
- Performed sequence homology analysis against known D. nodosus fimA sequences.
Main Results:
- The standard primer set failed to amplify the fimA gene from the M-SPAHL strain.
- Successful amplification was achieved using a modified primer set.
- DNA sequencing revealed that the M-SPAHL fimA sequence differed significantly from the Nepalese M strain.
- Predicted amino acid sequence of M-SPAHL fimA showed no homology to known serogroups, with the closest similarity to serotype F1.
Conclusions:
- The fimA gene sequence in D. nodosus serotype M strains can exhibit significant variation, challenging standard amplification and typing methods.
- Sequence dissimilarity between serologically related strains highlights the need for careful primer design and genetic analysis in D. nodosus research.
- The novel fimA sequence in M-SPAHL may have implications for vaccine development and diagnostic strategies targeting D. nodosus.
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