ABSTRACT
Borrelia miyamotoi is a spirochete bacterium related to Borrelia burgdorferi sensu lato, the cause of Lyme borreliosis, and vectored by ticks. In 2014, B. miyamotoi was identified in three questing Ixodes ricinus collected in the UK. We sought to confirm the presence of B. miyamotoi in the UK. Ticks were collected from four locations not previously investigated for B. miyamotoi or B. burgdorferi s.l. and of which two are considered as Lyme borreliosis "hotspots" based on hospital records of the disease. We independently confirm that B. miyamotoi is present in the UK and support the view that B. miyamotoi is likely to have a broad geographic distribution, at low levels. Our study also adds to the existing data on the distribution of B. burgdorferi s.l. in the UK and demonstrates that although the two "hotspots" had relatively high tick densities, they did not have the highest proportion of infected ticks.
Subject(s)
Borrelia/isolation & purification , Ixodes/microbiology , Ixodes/physiology , Animals , Borrelia burgdorferi/isolation & purification , England , Multiplex Polymerase Chain Reaction , Population Density , PrevalenceABSTRACT
TdPI, a tick salivary gland product related to Kunitz/BPTI proteins is a potent inhibitor of human beta-tryptase. Kinetic assays suggest that three of the four catalytic sites of tryptase are blocked by TdPI, and that the inhibition of one of these involves a peptide flanking the Kunitz head. In the course of the inhibition, tryptase cleaves TdPI at several positions. Crystal structures of the TdPI head, on its own and in complex with trypsin, reveal features that are not found in classical Kunitz/BPTI proteins and suggest the mode of interaction with tryptase. The loop of TdPI connecting the beta-sheet with the C-terminal alpha-helix is shortened, the disulphide-bridge pattern altered and N and C termini separated to produce a highly pointed molecule capable of penetrating the cramped active sites of tryptase. TdPI accumulates in the cytosolic granules of mast cells, presumably suppressing inflammation in the host animal's skin by tryptase inhibition.
Subject(s)
Serine Proteinase Inhibitors/metabolism , Ticks/metabolism , Tryptases/antagonists & inhibitors , Amino Acid Sequence , Animals , Aprotinin/chemistry , Catalytic Domain , Crystallography, X-Ray , Cytoplasmic Granules/metabolism , Cytosol/metabolism , Female , Humans , In Vitro Techniques , Male , Mast Cells/metabolism , Mice , Mice, Inbred BALB C , Models, Molecular , Molecular Sequence Data , Mutation , Protein Conformation , Serine Proteinase Inhibitors/chemistry , Serine Proteinase Inhibitors/genetics , Skin/cytologyABSTRACT
The abilities of the most common European genospecies of Borrelia burgdorferi sensu lato to survive blood meals taken by ticks feeding on birds were analyzed. A pattern of differential survival of the spirochetes in feeding ticks was observed. The result is consistent with the concept of selective transmission of Lyme borreliosis spirochetes.
