Department of Civil Engineering, Peter Kiewit Institute, University of Nebraska-Lincoln, Omaha, Nebraska 68588, USA.
Environ Sci Technol. 2010 Jun 1;44(11):4129-35. doi: 10.1021/es903520d.
Chronic wasting disease (CWD) and sheep scrapie can be transmitted via indirect environmental routes, and it is known that soil can serve as a reservoir of prion infectivity. Given the strong interaction between the prion protein (PrP) and soil, we hypothesized that binding to soil enhances prion resistance to enzymatic digestion, thereby facilitating prion longevity in the environment and providing protection from host degradation. We characterized the performance of a commercially available subtilisin enzyme, Prionzyme, to degrade soil-bound and unbound CWD and HY TME PrP as a function of pH, temperature, and treatment time. The subtilisin enzyme effectively degraded PrP adsorbed to a wide range of soils and soil minerals below the limits of detection. Signal loss occurred rapidly at high pH (12.5) and within 7 days under conditions representative of the natural environment (pH 7.4, 22 degrees C). We observed no apparent difference in enzyme effectiveness between bound and unbound CWD PrP. Our results show that although adsorbed prions do retain relative resistance to enzymatic digestion compared with other brain homogenate proteins, they can be effectively degraded when bound to soil. Our results also suggest a topical application of a subtilisin enzyme solution may be an effective decontamination method to limit disease transmission via environmental "hot spots" of prion infectivity.
慢性消耗病（CWD）和绵羊瘙痒病可以通过间接的环境途径传播，并且已知土壤可以作为朊病毒感染性的储库。鉴于朊病毒蛋白（PrP）与土壤之间的强烈相互作用，我们假设与土壤的结合增强了朊病毒对酶消化的抗性，从而延长了朊病毒在环境中的寿命，并提供了免受宿主降解的保护。我们研究了一种市售的枯草杆菌蛋白酶（Prionzyme）的性能，以降解土壤结合和未结合的 CWD 和 HY TME PrP，作为 pH 值、温度和处理时间的函数。该枯草杆菌蛋白酶可有效降解吸附在多种土壤和土壤矿物质上的 PrP，检测限以下。在高 pH 值（12.5）和 7 天内，在代表自然环境的条件下（pH 值 7.4，22 摄氏度），信号迅速丢失。我们没有观察到结合和未结合的 CWD PrP 之间酶有效性的明显差异。我们的结果表明，尽管吸附的朊病毒与其他脑匀浆蛋白相比确实保留了相对的抗酶消化性，但当与土壤结合时，它们可以被有效降解。我们的结果还表明，局部应用枯草杆菌蛋白酶溶液可能是一种有效的去污方法，可限制通过环境“热点”传播的朊病毒感染。
