The Calcaneum—On the Heels of Marsupial Locomotion

The potential for making functional interpretations from a single postcranial element for marsupials was investigated through morphometric analysis of the calcanea of 61 extant species from Australia and New Guinea. Extant species were grouped into locomotor categories and a canonical variates analysis was carried out on measurements of their calcanea. A relationship between measurements of the calcanea and the locomotor behavior of species was found, allowing for prediction of locomotor behavior from calcaneum morphometrics. This was applied to fossil marsupial taxa, from early–late Miocene/?Pliocene deposits at Riversleigh, in an attempt to determine their locomotor behavior. Hopping (saltatorial) taxa are distinguished from quadruped terrestrial taxa and taxa capable of climbing (arboreal and scansorial) by their relatively longer tuber calcis and wider calcaneal head, by their dorso-ventrally thicker calcaneal head, and by their calcaneocuboid facet being less steeply angled antero-posteriorly. Taxa capable of climbing are distinguished from quadruped terrestrial taxa by their shorter tuber calcis relative to the calcaneal head and by their smaller calcaneo-astragalar facet. The locomotor categories distinguished in this study (arboreal/scansorial, quadruped terrestrial, and saltatorial) highlight differences between species in their use of available substrates and thus are informative with regards to the structural components of their habitat. The results of this analysis can be used, in combination with other data, to make inferences about the habitats of paleocommunities at Riversleigh through the Miocene. The calcaneum is a dense and very robust element and, therefore, has a good chance of being preserved. This method provides a quick and easy way of inferring locomotion and has a wide potential for application to many fossil deposits because it requires only a single element.     

3H-1,2-benzoxathiepine 2,2-dioxides: a new class of isoform-selective carbonic anhydrase inhibitors

A new chemotype with carbonic anhydrase (CA, EC 4.2.1.1) inhibitory action has been discovered, the homo-sulfocoumarins (3H-1,2-benzoxathiepine 2,2-dioxides) which have been designed considering the (sulfo)coumarins as lead molecules. An original synthetic strategy of a panel of such derivatives led to compounds with a unique inhibitory profile and very high selectivity for the inhibition of the tumour associated (CA IX/XII) over the cytosolic (CA I/II) isoforms. Although the CA inhibition mechanism with these new compounds is unknown for the moment, we hypothesize that it may be similar to that of the sulfocoumarins, i.e. hydrolysis to the corresponding sulfonic acids which thereafter anchor to the zinc-coordinated water molecule within the enzyme active site.