TENTACLE PROBES

Background: A particularly difficult challenge is presented with the detection of differences in the genome between related species of pathogens. The differences can be extremely subtle - as little as one base (single nucleotide polymorphism, SNP) in a single gene. For example the gyrA gene of Bacillus anthracis has been reported to have 100% specificity but differs from Bacillus cereus in a single SNP and the situation is further exacerbated since the target sequence occurs in a part of the genome that is A/T nucleotide rich. Additionally, detection of the organisms in the field may result in collected samples which contain contaminants and non pathogenic variants that will interfere in the efficiency and specificity of assay reactions. Whereas some contaminants may be dealt with by lengthy sample purification, if available, the presence of closely related organisms at high concentrations may lead to a number of confounding results including, hard to eliminate, false positives. Our partnership with the United States Army Institute for Infectious Disease Research (USAMRIID) has led to novel sequence detection assays for example use in Real Time PCR of Bacillus anthracis and Yersina pestis that has resulted in:

No False Positives: The large overall footprint of the Tentacle Probe spanning a relatively large part of the target genome (35 - 45 bp) is able to distinguish between close families of homologous genes or pseudo genes, eliminating false positives for Bacillus anthracis, even in the presence of large contaminating amounts of similar organisms such as Bacillus cereus.

Difficult sequence insertions & deletions: The longer self-complimentary part of the probe, confers a tighter binding than is normally encountered with conventional dual labeled probes and resulted in higher DNA melting temperatures. Higher temperatures during the detection stage opens out any loop structures or similar tertiary structures on the genomic DNA making the assay suitable for the detection of insertions and deletions in Yersina pestis where the use of conventional probes failed, or lead to inconclusive results.

Download Bacillus anthracis Data Sheet:
Download publication on Tentacle Probes: