Extensive dissolution of live pteropods in the Southern Ocean

The carbonate chemistry of the surface ocean is rapidly changing with ocean acidification, a result of human activities. In the upper layers of the Southern Ocean, aragonite—a metastable form of calcium carbonate with rapid dissolution kinetics—may become undersaturated by 2050 (ref. 2). Aragonite undersaturation is likely to affect aragonite-shelled organisms, which can dominate surface water communities in polar regions. Here we present analyses of specimens of the pteropod Limacina helicina antarctica that were extracted live from the Southern Ocean early in 2008. We sampled from the top 200m of the water column, where aragonite saturation levels were around 1, as upwelled deep water is mixed with surface water containing anthropogenic CO2. Comparing the shell structure with samples from aragonite-supersaturated regions elsewhere under a scanning electron microscope, we found severe levels of shell dissolution in the undersaturated region alone. According to laboratory incubations of intact samples with a range of aragonite saturation levels, eight days of incubation in aragonite saturation levels of 0.94– 1.12 produces equivalent levels of dissolution. As deep-water upwelling and CO2 absorption by surface waters is likely to increase as a result of human activities2,4, we conclude that upper ocean regions where aragonite-shelled organisms are affected by dissolution are likely to expand

Design, Synthesis, and Structure\u2013Activity Relationships of Azolylmethylpyrroloquinolines as Nonsteroidal Aromatase Inhibitors

A small library of both [2,3-h] and [3,2-f] novel pyrroloquinolines equipped with an azolylmethyl group was designed and synthesized as non steroidal CYP19 aromatase inhibitors. The results showed that azolylmethyl derivatives 11, 13, 14, 21 and 22 exhibited an inhibitory potency on aromatase comparable to Letrozole chosen as a reference compound. When assayed on CYP11B1 (steroid-11\u3b2-hydroxylase) and CYP17 (17\u3b1-hydroxy/17,20-lyase), compound 22 was found to be the best and most selective CYP19 inhibitor of them all. In a panel of nine human cancer cell lines, all compounds were either slightly cytotoxic or not at all. Docking simulations were carried out to inspect crucial enzyme/inhibitor interactions such as hydrophobic interactions, hydrogen bonding and heme iron coordination. This study, along with the prediction of the pharmacokinetics of compounds 11, 13, 14, 21 and 22, demonstrates that the pyrroloquinoline scaffold represents a starting point for the development of new pyrroloquinoline-based aromatase inhibitors