Reactivity and Specificity of RNase T1, RNase A, and RNase H toward Oligonucleotides of RNA Containing 8-Oxo-7,8-dihydroguanosine.

Understanding how oxidatively damaged RNA interacts with ribonucleases is important because of its proposed role in the development and progression of disease. Thus, understanding structural aspects of RNA containing lesions generated under oxidative stress, as well as its interactions with other biopolymers, is fundamental. We explored the reactivity of RNase A, RNase T1, and RNase H toward oligonucleotides of RNA containing 8-oxo-7,8-dihydroguanosine (8oxoG). This is the first example that addresses this relationship and will be useful for understanding (1) how these RNases can be used to characterize the structural impact that this lesion has on RNA and (2) how oxidatively modified RNA may be handled intracellularly. 8-OxoG was incorporated into 10-16-mers of RNA, and its reactivity with each ribonuclease was assessed via electrophoretic analyses, circular dichroism, and the use of other C8-purine-modified analogues (8-bromoguanosine, 8-methoxyguanosine, and 8-oxoadenosine). RNase T1 does not recognize sites containing 8-oxoG, while RNase A recognizes and cleaves RNA at positions containing this lesion while differentiating if it is involved in H-bonding. The selectivity of RNase A followed the order C > 8-oxoG ≈ U. In addition, isothermal titration calorimetry showed that an 8-oxoG-C3'-methylphosphate derivative can inhibit RNase A activity. Cleavage patterns obtained from RNase H displayed changes in reactivity in a sequence- and concentration-dependent manner and displayed recognition at sites containing the modification in some cases. These data will aid in understanding how this modification affects reactivity with ribonucleases and will enable the characterization of global and local structural changes in oxidatively damaged RNA.

Tracing the origin of lithium in Li-ion batteries using lithium isotopes.

Rechargeable lithium-ion batteries (LIB) play a key role in the energy transition towards clean energy, powering electric vehicles, storing energy on renewable grids, and helping to cut emissions from transportation and energy sectors. Lithium (Li) demand is estimated to increase considerably in the near future, due to the growing need for clean-energy technologies. The corollary is that consumer expectations will also grow in terms of guarantees on the origin of Li and the efforts made to reduce the environmental and social impact potentially associated with its extraction. Today, the LIB-industry supply chain is very complex, making it difficult for end users to ensure that Li comes from environmentally and responsible sources. Using an innovative geochemical approach based on the analysis of Li isotopes of raw and processed materials, we show that Li isotope 'fingerprints' are a useful tool for determining the origin of lithium in LIB. This sets the stage for a new method ensuring the certification of Li in LIB.