Chemistry relies on encounters between reactive partners. Sometimes one of the partners changes shape during the wait, spoiling the desired outcome. Kim et al. designed a microfluidic device to keep such botched encounters from happening. The device operates at low temperatures to keep individual reactants from isomerizing. It also achieves fast flow rates to maximize encounters between reactants on a microsecond time scale.
Evolutionary trees of species can be reconstructed by pairwise comparison of their entire genomes. Such a comparison can be quantified by determining the number of events that change the order of genes in a genome. Earlier Erdem and Tillier formulated the pairwise comparison of entire genomes as the problem of planning rearrangement events that transform one genome to the other. We reformulate this problem as a planning problem to extend its applicability to genomes with multiple copies of genes and with unequal gene content, and illustrate its applicability and effectiveness on three real datasets: mitochondrial genomes of Metazoa, chloroplast genomes of Campanulaceae, chloroplast genomes of various land plants and green algae.
This result has implications for the very origin of dinosaurs--it was typically thought the earliest dinosaurs sprung up in the southern part of the world, but perhaps they could have arose in the north. It places the origin of dinosaurs approximately 247 million years ago, which is slightly earlier than previously posited. But like any new idea put forth, this one will be further scrutinized and has already been met with a healthy degree of skepticism in the paleontology community. Going against the flow is hard. One new study does not necessarily indicate a paradigm shift, but it can happen if these results are verified by other research groups.
The chemistry of the carbonyl group is essential to modern organic synthesis. The preparation of substituted, enantioenriched 1,3- or 1,5-dicarbonyls is well developed, as their disconnection naturally follows from the intrinsic polarity of the carbonyl group. By contrast, a general enantioselective access to quaternary stereocenters in acyclic 1,4-dicarbonyl systems remains an unresolved problem, despite the tremendous importance of 2,3-substituted 1,4-dicarbonyl motifs in natural products and drug scaffolds. Here we present a broad enantioselective and stereodivergent strategy to access acyclic, polysubstituted 1,4-dicarbonyls via acid-catalyzed [3,3]-sulfonium rearrangement starting from vinyl sulfoxides and ynamides. The stereochemistry at sulfur governs the absolute sense of chiral induction, whereas the double bond geometry dictates the relative configuration of the final products.
These structures reveal that the binding pocket for cooling agents is located at the cavity formed by the voltage-sensor like domain (VSLD) and the TRP domain (see panel B in the figure). They illustrate the structural bases for the recognition of menthol and icilin by TRPM8 and explain why Ca2 is required for icilin binding in TRPM8. These structures and subsequent functional studies unveil the unanticipated location for PIP2 binding at the membrane interfacial cavity established by multiple key subdomains in TRPM8 (see panel B in the figure). Notably, PIP2 can bind to the interfacial cavity in two different modes: partially or fully engaged. Furthermore, structural analyses reveal the molecular basis for the allosteric coupling between PIP2 and cooling agonists in TRPM8.