The ability of Staphylococcus aureus to adhere to adsorbed fibrinogen and fibrin is believed to be an important step in the initiation of bioinaterial and wound-associated infections. In this study, we show that the binding site in fibrinogen for the recently identified S. aureus fibrinogen-binding protein clumping factor (ClfA) is within the C-terminus of the fibrinogen y chain. S. aureus Newman cells expressing ClfA adhered to microtitre wells coated with recombinant fibrinogen purified from BHK cells, but did not adhere to wells coated with a purified recombinant fibrinogen variant where the 4 C-terminal residues of the y chain were replaced by 20 unrelated residues. In addition, a synthetic peptide corresponding to the 17 C-terminal amino acids of the fibrinogen y chain effectively inhibited adherence of ClfA-expressing cells to fibrinogen. In western ligand blots, a recombinant truncated ClfA protein called Clf33 (residues 221 -550) recognized intact recombinant fibrinogen y chains, but failed to recognize recombinant fibrinogen y chains where the 4 C-terminal amino acids were altered by deletion or substitution. Previous studies have shown that the C-terminal domain of fibrinogen y chains contains a binding site for the integrin . We now show that Clf33 inhibits ADPinduced, fibrinogen-dependent platelet aggregation in a concentration-dependent manner and inhibits adhesion of platelets to immobilized fibrinogen under fluid shear stress, indicating that the binding sites for the platelet integrin and the staphylococcal adhesin overlap. The interaction between Clf33 and fibrinogen was further characterized using the BIAcore biosensor. When soluble Clf33 was allowed to bind to immobilized fibrinogen, a Kd of 0.51 t-0.19 pM was experimentally determined using equilibrium binding data. It was also shown that the synthetic C-terminal y-chain peptide effectively inhibited this interaction.

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Understanding the distribution of fishing activity is fundamental to quantifying its impact on the seabed. Vessel monitoring system (VMS) data provides a means to understand the footprint (extent and intensity) of fishing activity. Automatic Identification System (AIS) data could offer a higher resolution alternative to VMS data, but differences in coverage and interpretation need to be better understood. VMS and AIS data were compared for individual scallop fishing vessels. There were substantial gaps in the AIS data coverage; AIS data only captured 26% of the time spent fishing compared to VMS data. The amount of missing data varied substantially between vessels (45–99% of each individuals' AIS data were missing). A cubic Hermite spline interpolation of VMS data provided the greatest similarity between VMS and AIS data. But the scale at which the data were analysed (size of the grid cells) had the greatest influence on estimates of fishing footprints. The present gaps in coverage of AIS may make it inappropriate for absolute estimates of fishing activity. VMS already provides a means of collecting more complete fishing position data, shielded from public view. Hence, there is an incentive to increase the VMS poll frequency to calculate more accurate fishing footprints.

Do large-scale industrial fisheries for sandeels impact 'human consumption' fishes by depriving them of food? In the North Sea, most sandeel fishing takes place on the Dogger Bank during spring. Here, we studied sandeel-fishery and sandeel-predatory fish interactions in 2 sampling grids, focussing on (1) how localised sandeels are distributed during the day (when feeding pelagically) and at night (when buried in the seabed); (2) how precisely the fishery can target localised sandeel concentrations; and (3) how tightly day/night sandeel distributions are linked to the local abundance of predatory fishes and their sandeel consumption. Sandeel abundance differed widely between both grids. Within each grid, marked day/night differences in distributions indicated extensive diurnal migrations, with centres of gravity of day and night distributions up to 15 km apart. Fishing effort was tightly matched with sandeel populations during the day and was far higher in the 'high sandeel density' grid. Only at the finest scale examined, effort was concentrated at sandbanks but not significantly matched with local sandeel numbers. This suggested either insufficient knowledge among fishers or vessel maneuverability issues, possibly relating to high mobility of sandeels. Ten predatory fishes (8 'human consumption' species) preyed on sandeels, most notably whiting and lesser weever. Spatial comparisons showed that the predominant sandeel predators were whiting during the day and lesser weever at night. Tight predator-prey interdependencies were revealed: whiting and weever exhibited 'aggregative responses' to sandeels, and most predators consumed more sandeels in the 'high sandeel density' grid. On the Dogger Bank, sandeel fishing effort is concentrated when and where sandeels are most available, but also where these are extensively and locally preyed upon by at least 10 predatory fish species. Hence concerns that this industrial fishery may indirectly impact predatory fishes by depriving them of food might have some basis.