A bird’s flying ability depends on the keel, a breastbone structure that anchors the muscles needed for flight. Researchers at Kyushu University found that a signaling pathway called TGF-β determines whether the keel forms. In flying birds, the signal stays active long enough to build it; in flightless birds, it turns off earlier. The study shows how small shifts in developmental timing can drive major evolutionary differences and may inform research on human chest deformities.

Z-form nucleic acids (ZNAs) are left-handed DNA/RNA structures implicated in innate immunity and cell death, yet the endogenous force driving their formation in vivo had remained unclear. In this study, the research team identified oxidative DNA modification as a molecular trigger for nucleic acid conformational switching. They showed that oxidative lesions in mitochondrial DNA (mtDNA), particularly 8-oxoG formation, induced a transition from canonical B-DNA to Z-DNA. The resulting oxidized Z-mtDNA was sensed by the Zα domain of ZBP1, activating a ZBP1–MAVS–caspase-8 signaling pathway that drove hepatocyte apoptosis. The findings were highly relevant to acetaminophen (APAP)-induced acute liver failure, in which the current therapy, N-acetylcysteine (NAC), rapidly loses efficacy beyond the early detoxification phase. The team demonstrated that APAP-induced oxidative stress promoted mtDNA oxidation and Z-DNA formation, thereby triggering the secondary hepatotoxicity that resisted NAC treatment. Importantly, pharmacological activation of the oxidative DNA repair enzyme OGG1 with TH10785 reversed Z-DNA back to B-DNA and achieved near-complete survival in delayed-treatment models. Together, these findings established oxidation-driven DNA conformational transition as a fundamental signaling mechanism and identified reversal of Z-DNA as a promising therapeutic strategy for acute liver failure.

A widely used method for measuring how well streams absorb excess nutrients has a hidden flaw: it systematically overestimates uptake length under high-nutrient conditions. Researchers at Duke Kunshan University have derived a corrected zero-order analytical approach that better captures stream nutrient processing when nutrients are abundant, improving the accuracy of tools used to assess river health and guide restoration decisions.