Identification of Ser-1275 and Ser-1309 as autophosphorylation sites of the insulin receptor 1This paper is dedicated to Prof. Günter Legler on the occasion of his 70th birthday.1

AbstractWe have identified Ser-1275 and Ser-1309 as novel serine autophosphorylation sites by direct sequencing of HPLC-purified tryptic phosphopeptides of the histidine-tagged insulin receptor kinase IRKD-HIS. The corresponding peptides (Ser-1275, amino acids 1272–1292; Ser-1309, amino acids 1305–1313) have been detected in the HPLC profiles of both the soluble kinase IRKD, which contains the entire cytoplasmic domain of the insulin receptor β-subunit, and the insulin receptor purified from human placenta. In contrast, a kinase negative mutant, IRKD-K1018A, did not undergo phosphorylation at either the tyrosine or serine residues, strongly suggesting that insulin receptor kinase has an intrinsic activity to autophosphorylate serine residues

Modern agglutinated foraminifera from the Hovgård ridge, fram strait, west of Spitsbergen: Evidence for a deep bottom current

Deep-water agglutinated foraminifera on the crest of the Hovgârd Ridge, west of Spitsbergen, consist mostly of large tubular astrorhizids. At a boxcore station collected from the crest of Hovgârd Ridge at a water depth of 1169 m, the sediment surface was covered with patches of large (1 mm diameter) tubular forms, belonging mostly to the species Astrorhiza crassatina Brady, with smaller numbers of Saccorhiza, Hyperammina, and Psammosiphonella. Non-tubutar species consisted mainly of opportunistic forms, such as Psammosphaera and Reophax. The presence of large suspension-feeding tubular genera as well as opportunistic forms point to the presence of deep currents at this locality that are strong enough to disturb the benthic fauna. This is confirmed by data obtained from sediment echosounding, which exhibit lateral variation in relative sedimentation rates within the Pleistocene sedimentary drape covering the ridge, indicative of winnowing in a south-easterly direction

Antarctic Bedmap data: Findable, Accessible, Interoperable, and Reusable (FAIR) sharing of 60 years of ice bed, surface, and thickness data

One of the key components of this research has been the mapping of Antarctic bed topography and ice thickness parameters that are crucial for modelling ice flow and hence for predicting future ice loss and the ensuing sea level rise. Supported by the Scientific Committee on Antarctic Research (SCAR), the Bedmap3 Action Group aims not only to produce new gridded maps of ice thickness and bed topography for the international scientific community, but also to standardize and make available all the geophysical survey data points used in producing the Bedmap gridded products. Here, we document the survey data used in the latest iteration, Bedmap3, incorporating and adding to all of the datasets previously used for Bedmap1 and Bedmap2, including ice bed, surface and thickness point data from all Antarctic geophysical campaigns since the 1950s. More specifically, we describe the processes used to standardize and make these and future surveys and gridded datasets accessible under the Findable, Accessible, Interoperable, and Reusable (FAIR) data principles. With the goals of making the gridding process reproducible and allowing scientists to re-use the data freely for their own analysis, we introduce the new SCAR Bedmap Data Portal (https://bedmap.scar.org, last access: 1 March 2023) created to provide unprecedented open access to these important datasets through a web-map interface. We believe that this data release will be a valuable asset to Antarctic research and will greatly extend the life cycle of the data held within it. Data are available from the UK Polar Data Centre: https://data.bas.ac.uk (last access: 5 May 2023​​​​​​​). See the Data availability section for the complete list of datasets.</p

Staphylococcal phosphoenolpyruvate-dependent phosphotransferase system: molecular cloning and nucleotide sequence of the Staphylococcus carnosus ptsI gene and expression and complementation studies of the gene product.

A digoxigenin-labeled DNA probe that was complementary to the gene ptsH and the beginning of the gene ptsI was used to clone a 3.2-kb HincII-BamHI restriction fragment containing the complete ptsI gene of Staphylococcus carnosus. The restriction fragment was cloned in the antisense orientation to the lac promoter in the low-copy-number vector pSU18. The nucleotide sequences of the ptsI gene, which encodes enzyme I (EC 2.7.3.9), and the corresponding flanking regions were determined. The primary translation product, derived from the nucleotide sequence, consists of 574 amino acids and has a calculated molecular weight of 63,369. Amino acid sequence comparison showed 47% similarity to enzyme I of Escherichia coli and 37% similarity to the enzyme I domain of the multiphosphoryl transfer protein of Rhodobacter capsulatus. The histidinyl residue at position 191 could be identified as the probable phosphoenolpyruvate-dependent phosphorylation site of enzyme I of S. carnosus because of sequence homologies with the peptide sequences of enzyme I-active sites of Enterococcus faecalis and Lactococcus lactis. Several in vivo and in vitro complementation studies with the enzyme I ptsI genes of S. carnosus and the E. coli ptsI mutant JLT2 were carried out. The generation times and interaction between enzyme I with histidine-containing protein from gram-positive and gram-negative bacteria were measured in a phosphoryl group transfer test

Coastal bathymetry in central Dronning Maud Land controls ice shelf stability

Knowledge of the bathymetry of Antarctica’s margins is crucial for models and interpretations of ice-ocean interactions and their influence on ongoing and future sea level change, but remains patchy where ice shelves and multi-year sea ice block measurements. Here, we present a bathymetric model for the central Dronning Maud Land margin, based on a constrained inversion of airborne gravity data. It shows the cavities beneath the region’s two ice shelves to be much deeper than in existing bathymetric compilations, but to be shielded from Warm Deep Water ingress and basal melting by the presence of shallow bathymetric sills along the continental shelf. Over areas of multi-year sea ice, the model returns bathymetric estimates of similar accuracy to gravity interpolation-based methods over open water. Airborne gravity thus presents an opportunity to bathymetrically map hundreds of thousands of square kilometres of the most inaccessible margins of Antarctica at resolutions adequate for regional and global oceanographic and glaciological modelling and interpretation