Strontium isotopes are a powerful tool for investigating the geographical origins of people and animals but assignment of provenance requires reference maps and databases. This paper presents a map of strontium isotope variations across Britain for use in archaeological and other studies, and is produced by direct measurement of strontium isotope compositions of biosphere components, predominantly plants. The map characterizes the biosphere signature of specific lithologies: a technique that is applicable worldwide. Marine-derived strontium, from both rainwater and coastal sea-splash and spray, is an important contribution to the British biosphere, particularly on the western seaboard, which is subject to high rainfall and prevailing westerly winds. Supplementary material: Methods, full data table, and full-size version of Figure 1b are available at http://www.geolsoc.org.uk/SUP18388 .

DNA gyrase, an essential type II topoisomerase, mediates negative supercoiling of the bacterial chromosome, thereby affecting the processes of DNA replication, transcription, recombination and repair. The gyrB gene from the Gram-negative soil bacterium Myxococcus xanthus was sequenced. The sequence predicts a protein of 81 5 amino acid residues displaying significant homology to all known GyrB proteins. A 6-His-GyrB fusion protein was overexpressed in Escherichia coli and purified to near homogeneity using affinity chromatography on Ni-nitrilotriacetic acid-agarose and novobiocin-Sepharose columns. The fusion protein bound novobiocin and cross-reacted with anti-€. coli GyrB antibodies, indicating structural and functional similarities to the E. coli DNA GyrB. The gene was mapped to the region of the origin of replication (oriC) of M. xanthus.

In early 2005 a particularly severe storm exposed human bones on the foreshore immediately east of the ruins of St Thomas' Kirk. The subsequent excavation recovered fourteen individual inhumations. The skeletons exhibited a relatively high number of pathological conditions and evidence of a diet that included fish, meat and dairy products. Isotopic analysis confirms that one of the individuals was from either the outer Hebrides or Northern Shetland while the rest originated from Orkney. The graves were arranged in distinct grave plots on a north/south aligned row, clustered particularly close to the east side of St Thomas' Kirk. Imported medieval pottery, of a type unknown in Orkney or indeed Scotland, was recovered from the graves.