Swedish Defence Research Agency

About: Swedish Defence Research Agency is a government organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Radar & Laser. The organization has 1413 authors who have published 2731 publications receiving 56083 citations. The organization is also known as: Totalförsvarets forskningsinstitut.

Antimicrobial Resistance Profiles of Campylobacter jejuni Isolates from Wild Birds in Sweden

Abstract: In order to determine the occurrence and frequency of resistant strains of the bacterium Campylobacter jejuni and to establish baseline MICs in isolates from an environmental reservoir, the resistance profiles of 10 antimicrobial substances were determined for 137 C. jejuni isolates from wild birds in Sweden. Observed MICs were generally low, with only low to moderate incidence of resistance to the tested compounds. One isolate, however, was resistant to nalidixic acid and ciprofloxacin, indicating that quinolone-resistant genotypes of C. jejuni have the potential to spread to wild bird hosts.

VHF/UHF bistatic and passive SAR ground imaging

Abstract: Bistatic and passive radar are emerging technologies for covert ground surveillance based on cooperative or non-cooperative transmitters, respectively. The latter uses transmitters of opportunity, e.g. terrestrial digital video broadcasting (DVB-T). In the paper, we show results from two unique experiments conducted using airborne systems operating in the VHF and UHF bands. The first experiment investigates UHF-band passive synthetic aperture radar (SAR) in receive-only mode. DVB-T signals transmitted from a 300-m tall mast are used and SAR images are formed at ranges up to 15 km. The second experiment investigates VHF-band bistatic SAR with a transmitting airborne radar and a receive-only system on a small helicopter. Results show significantly higher signal-to-clutter ratio for man-made objects in forested areas at bistatic elevation angles of 20°.

Only the complex N559-glycan in the synaptic vesicle glycoprotein 2C mediates high affinity binding to botulinum neurotoxin serotype A1

Abstract: The extraordinary potency of botulinum neurotoxins (BoNTs) is mediated by their high neurospecificity, targeting peripheral cholinergic motoneurons leading to flaccid paralysis and successive respiratory failure. Complex polysialo gangliosides accumulate BoNTs on the plasma membrane and facilitate subsequent binding to synaptic vesicle membrane proteins which results in toxin endocytosis. The luminal domain 4 (LD4) of the three synaptic vesicle glycoprotein 2 (SV2) isoforms A-C mediates uptake of the clinically most relevant serotype BoNT/A. SV2C-LD4 exhibits the strongest protein-protein interaction and comprises five putative N‑glycosylation sites. Here, we expressed human SV2C‑LD4 fused to human IgG‑Fc in prokaryotic and eukaryotic expression systems to analyse the effect of N‑glycosylation of SV2C on the interaction with BoNT/A. Mass spectrometric analysis of gSV2CLD-Fc demonstrates glycosylation of N534, N559 and N565, the latter two residing at the BoNT/A interface. Mutational analysis exhibits that only the N559‑glycan, but not N565-glycan increases affinity of BoNT/A to human gSV2C‑LD4. The N559‑glycan was characterised as of complex core-fucosylated type with a heterogeneity ranging up to tetra-antennary structure with bisecting N‑acetylglucosamine which can establish extensive interactions with BoNT/A. The mutant gSV2CLD-Fc N559A displayed a 50-fold increased dissociation rate k d resulting in an overall 12-fold decreased binding affinity in surface plasmon resonance experiments. The delayed dissociation might provide BoNT/A more time for endocytosis into synaptic vesicles. In conclusion, we show the importance of the complex N559‑glycan of SV2C-LD4, adding a third anchor point beside a ganglioside and the SV2C-LD4 peptide, for BoNT/A neuronal cell surface binding and uptake.