Memory for own behaviour in pinnipeds.

Pinnipeds are aquatic predators feeding on a vast range of prey, and their social behaviour differs greatly between species (from extreme polygyny in some sea lions to monogamy in some true seals). It has been hypothesised that the foraging and social complexity of their lifestyle should drive the evolution of their cognitive abilities. To investigate how aware pinnipeds are of their own behaviour, a grey seal (Halichoerus grypus), two harbour seals (Phoca vitulina) and four South American sea lions (Otaria flavescens) were trained to repeat their own behaviour on command. Three already trained behaviours were used, and the animal was asked to repeat the behaviour twice to ensure that the animal recalled its own behaviour and not the command given for the previous behaviour. All three species could recall their own behaviour significantly better than by chance. The duration for which the animals could recall their behaviour was tested using a staircase paradigm. A delay was implemented between the completion of the behaviour and the command to repeat it. The delay was increased after correct responses and decreased after incorrect responses. The performance of all species fell towards chance level after 12-18 s, with no significant difference between species. These results indicate that sea lions and true seals are aware of their own behaviour and that true seals have similar short-term memory abilities. It also shows that pinnipeds have less developed short-term memory abilities compared to other aquatic predators, such as the bottlenose dolphin. The complexity of pinniped foraging and social behaviour does not seem to have driven the evolution of short-term memory abilities in these animals but might have contributed to their ability to recall their own behaviour.

The use of seal scarers as a protective mitigation measure can induce hearing impairment in harbour porpoises.

Acoustic deterrent devices (ADDs) are used to deter seals from aquacultures but exposure of harbour porpoises (Phocoena phocoena) occurs as a side-effect. At construction sites, by contrast, ADDs are used to deter harbour porpoises from the zone in which pile driving noise can induce temporary threshold shifts (TTSs). ADDs emit such high pressure levels that there is concern that ADDs themselves may induce a TTS. A harbour porpoise in human care was exposed to an artificial ADD signal with a peak frequency of 14 kHz. A significant TTS was found, measured by auditory evoked potentials, with an onset of 142 dB re 1 µPa2s at 20 kHz and 147 dB re 1 µPa2s at 28 kHz. The authors therefore strongly recommend to gradually increase and down regulate source levels of ADDs to the desired deterrence range. However, further research is needed to develop a reliable relationship between received levels and deterrence.

Control of Amphiphile Self-Assembly via Bioinspired Metal Ion Coordination.

Inspired by marine siderophores that exhibit a morphological shift upon metal coordination, hybrid peptide-polymer conjugates that assemble into different morphologies based on the nature of the metal ion coordination have been designed. Coupling of a peptide chelator, hexahistidine, with hydrophobic oligostyrene allows a modular strategy to be established for the efficient synthesis and purification of these tunable amphiphiles (oSt(His)6). Remarkably, in the presence of different divalent transition metal ions (Mn, Co, Ni, Cu, Zn, and Cd) a variety of morphologies were observed. Zinc(II), cobalt(II), and copper(II) led to aggregated micelles. Nickel(II) and cadmium(II) produced micelles, and multilamellar vesicles were obtained in the presence of manganese(II). This work highlights the significant potential for transition metal ion coordination as a tool for directing the assembly of synthetic nanomaterials.

Observing supernova 1987A with the refurbished Hubble Space Telescope.

Observations with the Hubble Space Telescope (HST), conducted since 1990, now offer an unprecedented glimpse into fast astrophysical shocks in the young remnant of supernova 1987A. Comparing observations taken in 2010 with the use of the refurbished instruments on HST with data taken in 2004, just before the Space Telescope Imaging Spectrograph failed, we find that the Lyα and Hα lines from shock emission continue to brighten, whereas their maximum velocities continue to decrease. We observe broad, blueshifted Lyα, which we attribute to resonant scattering of photons emitted from hot spots on the equatorial ring. We also detect N v λλ1239, 1243 angstrom line emission, but only to the red of Lyα. The profiles of the N v lines differ markedly from that of Hα, suggesting that the N4+ ions are scattered and accelerated by turbulent electromagnetic fields that isotropize the ions in the collisionless shock.

ChemGPS-NP: tuned for navigation in biologically relevant chemical space.

Natural compounds are evolutionary selected and prevalidated by Nature, displaying a unique chemical diversity and a corresponding diversity of biological activities. These features make them highly interesting for studies of chemical biology, and in the pharmaceutical industry for development of new leads. Of utmost importance, for the discovery of new biologically active compounds, is the identification and charting of the corresponding biologically relevant chemical space. The primary key to this is the coverage of the natural products' chemical space. Here we introduce ChemGPS-NP, a new tool tuned for handling the chemical diversity encountered in natural products research, in contrast to previous tools focused on the much more restricted drug-like chemical space. The aim is to provide a framework for making compound classification and comparison more efficient and stringent, to identify volumes of chemical space related to particular biological activities, and to track changes in chemical properties due to, for example, evolutionary traits and modifications in biosynthesis. Physical-chemical properties not directly discernible from structural data can be discovered, making selection more efficient and increasing the probability of hit generation when screening natural compounds and analogues.

Expanding the ChemGPS chemical space with natural products.

Recently various attempts have been made to increase the efficacy and precision of chemical libraries used in high-throughput screening (HTS) drug discovery approaches. One such approach is ChemGPS, which provides a defined chemical space for prescreening evaluation of chemical compound properties or virtual dereplication. In the present study, ChemGPS has been applied to a set of natural products shown to exhibit cyclooxygenase-1 and/or -2 (COX-1/2) inhibition. With the purpose of defining chemical properties and linking these to the observed mode of enzyme inhibition, this resulted in two lines of reasoning. On one hand several specific features of these compounds have been identified and discussed. Overall COX inhibition was frequently correlated with the presence of at least one ring in the structure, fragments exhibiting structural rigidity, and a relatively large molecular size. The concept "size" includes several parameters, e.g., molecular volume, weight, and number of bonds. On the other hand, and possibly even more important, was the unexpected finding that the natural products studied to a large extent fell outside the defined ChemGPS chemical space. Therefore, we also propose an expanded space for natural products: ChemGPS-NP.