A species-specific digital PCR assay for the endangered blue racer (Coluber constrictor foxii) in Canada.

The only population of the endangered blue racer (Coluber constrictor foxii) in Canada occurs on Pelee Island, Ontario. The species is threatened by multiple factors, including habitat degradation and loss, road mortality, persecution, and potentially predation. We designed and evaluated the performance of an environmental DNA droplet digital PCR assay that can be used for multiple facets of conservation of this species. We tested the assay in silico and in vitro using DNA of blue racers and co-occurring snake species and estimated the LOD and LOQ using synthetic DNA. As wild turkey predation has been suggested to negatively affect racers, we tested the assay on eight wild turkey faecal samples. Our assay is specific, can detect the target species at very low levels of concentration (0.002 copies/µL), and can accurately quantify copy numbers ≥ 0.26 copies/µL. We detected no racer DNA in any wild turkey faecal sample. More faecal samples collected at strategic locations during snake peak activity on Pelee Island would enable a more thorough assessment of the possibility of turkey predation. Our assay should be effective for other environmental samples and can be used for investigating other factors negatively affecting blue racers, for example, helping to quantify blue racer habitat suitability and site occupancy.

Studying the factors that impact the dissolution characteristic of complex drug product.

This article summarizes the critical factors involved in product development of a single dosage form formulated by compacting ethyl cellulose (EC) coated controlled release pellets into a tablet. The greatest challenge associated with this type of complex system is to minimize the effect of compression on the drug release. The effects of compression on the drug release were optimized with combination of the following factors (1) particle size of the core pellets, (2) the selection of the coating polymer's viscosity grade, and (3) emergence of cushioning agents. The optimization of these factors provided superior protection for the controlled release coated pellets; therefore, the desired drug release from the tablet was successfully achieved as designed. However, the drug release rates from the coated pellets before and after the compression were minimized and exhibited only a slight difference.