Anna M. Rovira

Redesigning the Coumarin Scaffold into Small Bright Fluorophores with Far-Red to Near-Infrared Emission and Large Stokes Shifts Useful for Cell Imaging

Among the palette of previously described fluorescent organic molecules, coumarins are ideal candidates for developing cellular and molecular imaging tools due to their high cell permeability and minimal perturbation of living systems. However, blue-to-cyan fluorescence emission is usually difficult in in vivo applications due to the inherent toxicity and poor tissue penetration of short visible light wavelengths. Here, we introduce a new family of coumarin-based fluorophores, nicknamed COUPY, with promising photophysical properties, including emission in the far-red/near-infrared (NIR) region, large Stokes shifts, high photostability, and excellent brightness. COUPY fluorophores were efficiently synthesized in only three linear synthetic steps from commercially available precursors, with the N-alkylation of a pyridine moiety being the key step at the end of the synthetic route, as it allows for the tuning of the photophysical properties of the resulting dye. Owing to their low molecular weights, COUPY dyes show excellent cell permeability and accumulate selectively in nucleoli and/or mitochondria of HeLa cells, as their far-red/NIR fluorescence emission is easily detected at a concentration as low as 0.5 μM after an incubation of only 20 min. We anticipate that these coumarin scaffolds will open a way to the development of novel coumarin-based far-red to NIR emitting fluorophores with potential applications for organelle imaging and biomolecule labeling.

Conservation Genetics of Dichoropetalum schottii (Apiaceae): Is the Legal Protection of Edge Populations Consistent with the Genetic Data?

Dichoropetalum schottii is a species that lives at low to medium altitudes in the southern European mountain ranges, from the Balkans (N Greece) to the Pyrenees. Its legal protection status is not homogeneous along its distribution range, as only some of its edge populations, in the Pyrenees, are protected. Here, by means of allozyme electrophoresis, we examine the genetic variability of populations representing four different regions within its distribution area (Pyrenees, Maritime Alps, Karst Plateau in the SW Slovenia—NE Italy border region, and Pindus Mountains in Greece). The species as a whole exhibits relatively high levels of genetic diversity, partly due to the occurrence of several duplications among the loci surveyed. Genetic differentiation among populations and regions was low, which could be interpreted as the result of recent allopatric fragmentation. We conclude that the species as a whole is not threatened, and that the currently protected populations are, paradoxically, the least valuable from the genetic point of view.