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Electronic tags are widespread tools for studying aquatic animal behavior; however, tags risk behavioral manipulation and negative welfare outcomes. During an experiment to test behavioral differences of Atlantic salmon Salmo salar in different aquaculture cage types, including ones expected to elicit deeper swimming behavior, we found negative tagging effects depending on whether cages were depth-modified. In the experiment, data storage tags implanted in Atlantic salmon tracked their depth behavior and survival in unmodified sea-cages and depth-modified sea-cages that forced fish below or into a narrow seawater- or freshwater-filled snorkel tube from a 4 m net roof to the surface. All tagged individuals survived in unmodified cages; however, survival was reduced to 62% in depth-modified cages. Survivors in depth-modified cages spent considerably less time above 4 m than those in unmodified cages, and dying individuals in depth-modified cages tended to position in progressively shallower water. The maximum depth that fish in our study could attain neutral buoyancy was estimated at 22 m in seawater. We calculated that the added tag weight in water reduced this to 8 m, and subtracting the tag volume from the peritoneal cavity where the swim bladder reinflates reduced this further to 4 m. We conclude that the internal tag weight and volume affected buoyancy regulation as well as the survival and behavior of tagged fish. Future tagging studies on aquatic animals should carefully consider the buoyancy-related consequences of internal tags with excess weight in water, and the inclusion of data from dying tagged animals when estimating normal depth behaviors. [ABSTRACT FROM AUTHOR]

Insulin is a key hormone of human metabolism with major therapeutic importance for both types of diabetes. New insulin analogues with more physiological profiles and better glycemic control are needed, especially analogues that preferentially bind to the metabolic B-isoform of insulin receptor (IR-B). Here, we aimed to stabilize and modulate the receptor-compatible conformation of insulin by covalent intra-chain crosslinking within its B22-B30 segment, using the Cu(I)-catalyzed Huisgen 1,3-dipolar cycloaddition reaction of azides and alkynes. This approach resulted in 14 new, systematically crosslinked insulin analogues whose structures and functions were extensively characterized and correlated. One of the analogues, containing a B26-B29 triazole bridge, was highly active in binding to both IR isoforms, with a significant preference for IR-B. Our results demonstrate the potential of chemistry-driven modulation of insulin function, also shedding new light on the functional importance of hormone's B-chain C-terminus for its IR-B specificity.

Enhanced metabolism of fucose through fucosidase overexpression is a signature of some cancer types, thus suggesting that fucosidase-targetted ligands could play the role of drug-delivery vectors. Herein, we describe the synthesis of a new series of pyrrolidine-ferrocene conjugates, consisting of a L-fuco-configured dihydroxypyrrolidine as the fucosidase ligand armed with a cytotoxic ferrocenylamine moeity. Three-dimensional structures of several of these fucosidase inhibitors reveal transition-state-mimicking (3)E conformations. Elaboration with the ferrocenyl moiety results in sub-micromolar inhibitors of both bovine and bacterial fucosidases, with the 3D structure of the latter revealing electron density indicative of highly mobile alkylferrocene compounds. The best compounds show a strong antiproliferative effect, with up to 100% inhibition of the proliferation of MDA-MB-231 cancer cells at 50 μM., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)