Shell scarring in Calliostoma zizyphinum (Prosobranch: Trochidae) from Strangford Lough, Northern Ireland.

Pink and white shells of Calliostoma zizyphinum show both undamaged and damaged scars. White shelled individuals predominate in Strangford Lough, Northern Ireland where Calliostoma densities and scarring levels are high. No white shells were found intertidally, outside the entrance channel to the Lough. Significant differences occur in the size of Calliostoma shells between sampling sites but not between different colour morphs at each site. However in pooled samples, pink individuals are significantly larger than white individuals. When sites and morphs are considered separately, pink Calliostoma density is negatively correlated with water movement. At sites where pink Calliostoma occur, the percentage of pink shelled individuals is negatively correlated with total Calliostoma density. Damaged and undamaged scarring values per unit area of shell, show highly significant differences between sites and damaged scars are significantly higher in white individuals. Undamaged scars are not correlated with any of the environmental parameters recorded, but are positively correlated with damaged scars suggesting a common causative factor. The level of damaged scarring is positively correlated with crab/total Calliostoma ratio at all sites and where each colour morph was considered separately. Multiple regression analyses reveal that crab/Calliostoma ratios account for 42% of the between site variation in damaged scars. Significantly higher levels of damaged scars are found at sites with high crab densities and significantly larger individuals are found at sites where crab densities are intermediate in value. The largest and most highly scarred individuals occur at sites with most coarse substrata where Calliostoma are present in their lowest densities. The higher scarring levels and smaller size of white individuals reflect either higher mortality or reduced growth in white shelled Calliostoma.

A Family of Helminth Molecules that Modulate Innate Cell Responses via Molecular Mimicry of Host Antimicrobial Peptides

Over the last decade a significant number of studies have highlighted the central role of host antimicrobial (or defence) peptides in modulating the response of innate immune cells to pathogen-associated ligands. In humans, the most widely studied antimicrobial peptide is LL-37, a 37-residue peptide containing an amphipathic helix that is released via proteolytic cleavage of the precursor protein CAP18. Owing to its ability to protect against lethal endotoxaemia and clinically-relevant bacterial infections, LL-37 and its derivatives are seen as attractive candidates for anti-sepsis therapies. We have identified a novel family of molecules secreted by parasitic helminths (helminth defence molecules; HDMs) that exhibit similar biochemical and functional characteristics to human defence peptides, particularly CAP18. The HDM secreted by Fasciola hepatica (FhHDM-1) adopts a predominantly alpha-helical structure in solution. Processing of FhHDM-1 by F. hepatica cathepsin L1 releases a 34-residue C-terminal fragment containing a conserved amphipathic helix. This is analogous to the proteolytic processing of CAP18 to release LL-37, which modulates innate cell activation by classical toll-like receptor (TLR) ligands such as lipopolysaccharide (LPS). We show that full-length recombinant FhHDM-1 and a peptide analogue of the amphipathic C-terminus bind directly to LPS in a concentration-dependent manner, reducing its interaction with both LPS-binding protein (LBP) and the surface of macrophages. Furthermore, FhHDM-1 and the amphipathic C-terminal peptide protect mice against LPS-induced inflammation by significantly reducing the release of inflammatory mediators from macrophages. We propose that HDMs, by mimicking the function of host defence peptides, represent a novel family of innate cell modulators with therapeutic potential in anti-sepsis treatments and prevention of inflammation.

Massive stars exploding in a He-rich circumstellar medium - I. Type Ibn (SN 2006jc-like) events

We present new spectroscopic and photometric data of the Type Ibn supernovae 2006jc, 2000er and 2002ao. We discuss the general properties of this recently proposed supernova family, which also includes SN 1999cq. The early-time monitoring of SN 2000er traces the evolution of this class of objects during the first few days after the shock breakout. An overall similarity in the photometric and spectroscopic evolution is found among the members of this group, which would be unexpected if the energy in these core-collapse events was dominated by the interaction between supernova ejecta and circumstellar medium. Type Ibn supernovae appear to be rather normal Type Ib/c supernova explosions which occur within a He-rich circumstellar environment. SNe Ibn are therefore likely produced by the explosion of Wolf-Rayet progenitors still embedded in the He-rich material lost by the star in recent mass-loss episodes, which resemble known luminous blue variable eruptions. The evolved Wolf-Rayet star could either result from the evolution of a very massive star or be the more evolved member of a massive binary system. We also suggest that there are a number of arguments in favour of a Type Ibn classification for the historical SN 1885A (S-Andromedae), previously considered as an anomalous Type la event with some resemblance to SN 1991bg.

Development of XUV lasers at the RAL central laser facility

Recent progress in the development of XUV lasers by research teams using high-power and ultrashort-pulse Nd:glass and KrF laser facilities at the Rutherford Appleton Laboratory is reviewed. Injector-amplifier operation and prepulse enhanced output of the Ge XXIII collisional laser driven by a kilojoule glass laser, enhanced gain in CVI recombination with picosecond CPA drive pulses from a glass laser, and optical field ionization and XUV harmonic generation with a KrF CPA laser are described.