Duplex Structure of Double-Stranded RNA Provides Stability against Hydrolysis Relative to Single-Stranded RNA.

Phosphodiester bonds in the backbones of double-stranded (ds)RNA and single-stranded (ss)RNA are known to undergo alkaline hydrolysis. Consequently, dsRNA agents used in emerging RNA interference (RNAi) products have been assumed to exhibit low chemical persistence in solutions. However, the impact of the duplex structure of dsRNA on alkaline hydrolysis has not yet been evaluated. In this study, we demonstrated that dsRNA undergoes orders-of-magnitude slower alkaline hydrolysis than ssRNA. Furthermore, we observed that dsRNA remains intact for multiple months at neutral pH, challenging the assumption that dsRNA is chemically unstable. In systems enabling both enzymatic degradation and alkaline hydrolysis of dsRNA, we found that increasing pH effectively attenuated enzymatic degradation without inducing alkaline hydrolysis that was observed for ssRNA. Overall, our findings demonstrated, for the first time, that key degradation pathways of dsRNA significantly differ from those of ssRNA. Consideration of the unique properties of dsRNA will enable greater control of dsRNA stability during the application of emerging RNAi technology and more accurate assessment of its fate in environmental and biological systems, as well as provide insights into broader application areas including dsRNA isolation, detection and inactivation of dsRNA viruses, and prebiotic molecular evolution.

Colonial foresters versus agriculturalists: the debate over climate change and cocoa production in the Gold Coast.

This article draws attention to the unfolding debate concerning forest cover loss, climatic change, and declining cocoa production in the Gold Coast (colonial Ghana) during the early twentieth century. It argues that, although desiccationist theory was prevalent, its acceptance among colonial authorities in the Gold Coast was far from hegemonic. There were important dissenting colonial voices, particularly among agriculturalists, who argued that declining cocoa yields were due to plant diseases, most notably cocoa swollen shoot disease. It was based on the latter's non-environmental model of disease transmission, rather than the premises of desiccation science, that the government's postwar "cutting out campaign" of cocoa was predicated. Nevertheless, the foresters' correlation of the deterioration of cocoa areas with fears of desiccation was not without its effects on state practice, providing the rationale for an accelerated program of forest reservations in the 1930s.