A slow replication rate in animals and was characterized by a longer incubation time to disease. Thus, the titer of sPMCA-derived 263K PrPSc form was underestimated. In previous studies, significant effort has been spent in an attempt to establish a relationship between incubation time to disease and PrPSc physical properties such as ABT-263 conformational stability. Because conformational stability appears to control the intrinsic fragility of aggregates, conformational stability is likely to impact the overall rate and yield of prion amplification. The current work suggests that strainspecific differences in PrPSc elongation rate might add another dimension to a complex relationship between conformational stability, intrinsic fragility and incubation time to disease. The strains with short incubation time to disease were found to display higher elongation rates than the strains with long incubation times. However, the potential relationship between elongation rates and incubation time should be considered with a great caution, because an increase in elongation rates for PMCAb-adapted PrPSc does not lead to shorter incubation times. The current studies illustrated that a high yield in prion amplification could be achieved by considerably shortening the length of incubation intervals in PMCAb, at least for some strains. For optimal results, the length of incubation intervals should be optimized individually for each strain.

Despite of such inconvenience, the approach introduced by the current study is worthy of effort in developing rapid prion detection assays. The commercial application of genetically engineered crops in agricultural production has aroused great biosafety concerns worldwide. The potential environmental impacts caused by the cultivation of the GE crops are the most debated issues. Transgene flow from a GE crop into populations of wild or weedy relatives and its potential ecological risks is considered as a key environmental problem. gene flow from a crop to its wild relatives has been widely documented in the last decades. However, our knowledge on the role of introgressed transgenes that confer novel traits with a strong selective advantage in changing the evolutionary process of wild or weedy populations is still limited. Therefore, assessing potential environmental risks caused by the extensive cultivation of GE crops prior to their commercialization becomes a common practice. The study of potential ecological consequences created by transgene flow to wild relatives particularly the coexisting and conspecific weeds will provide solid bases for environmental risk assessment. The fate of weedy populations that acquired transgenes through gene flow is largely different, depending on the fitness effect of the introgressed transgenes under given environmental conditions. If the introgressed transgenes can increase fitness, the transgenes will enhance the competitiveness and invasiveness of the weedy populations, leading to the rapid spread of the transgenes in the weedy populations, and vice versa. Thus, estimating fitness effect of transgenes on weedy populations is essential. Rice is an important world crop providing staple food for nearly one half of the global population.