Orthogonally Sequential Activation of Self-Powered DNAzymes Cascade for Reliable Monitoring of mRNA in Living Cells.

Ratiometric imaging of tumor-related mRNA is significant, yet spatiotemporally resolved regulation on the ratiometric signals to avoid non-specific activation in the living cells remains challenging. Herein, orthogonally sequential activation of concatenated DNAzyme circuits is, first, developed for Spatio Temporally regulated Amplified and Ratiometric (STAR) imaging of TK1 mRNA inside living cells with enhanced reliability and accuracy. By virtue of the synthesized CuO/MnO2 nanosheets, orthogonally regulated self-powered DNAzyme circuits are operated precisely in living cells, sequentially activating two-layered DNAzyme cleavage reactions to achieve the two ratiometric signal readouts successively for reliable monitoring of low-abundance mRNA in living cells. It is found that the ratiometric signals can only be derived from mRNA over-expressed tumor cells, also irrespective of probes' delivery concentration. The presented approach could provide new insight into orthogonally regulated ratiometric systems for reliable imaging of specific biomarkers in living cells, benefiting disease precision diagnostics.

Social rank-dependent effects of testosterone on huddling strategies in mice.

Huddling behavior, a typical social interaction among animals, has the benefits of obtaining social support and adapting environment. Huddling behavior is determined by social (social hierarchy), environmental factors (stress events), and the neuroendocrine system. Nevertheless, the huddling behavior of different social hierarchies and the underlying mechanisms have not been fully elucidated. In the present study, acute 2-methyl-2-thiazoline (2 MT) can induce huddling behavior and significantly increase serum levels of testosterone (T) in mice; and the increased T level was positively correlated with huddling behavior. Further, the T treatment significantly increased the huddling behavior in mice under 2 MT exposure condition. More interestingly, T can quickly promote dominant individuals to occupy safe positions when huddling together under predator odor. Collectively, T can rapidly regulate the individual's adaptive response to threats in a social rank-dependent manner, which provides a new perspective for the in-depth study of the influencing factors and underlying mechanisms of huddling behavior.