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Tick salivary gland aquaporins: characterization and importance

Reference	BB/C517833/1
Principal Investigator / Supervisor	Dr Alan Bowman
Co-Investigators / Co-Supervisors	Dr Andrew Ball, Professor Stefan Hoppler
Institution	University of Aberdeen
Department	School of Medical Sciences
Funding type	Research
Value (£)	269,179
Status	Completed
Type	Research Grant
Start date	01/06/2005
End date	30/11/2008
Duration	42 months

Abstract

Ticks remain the most economically important ectoparasite to global livestock production and are the most important vectors of human disease in Europe and North America. Widespread and increasing resistance to most available acaracides necessitates the development of new acaracides which are likely to be against novel, non-traditional targets. The salivary glands are of critical importance to ticks acting as the organs of osmoregulation and the route of pathogen transmission and may prove to be an attractive drug target. Following on from the PI¿s extensive research on tick salivary gland physiology, we propose to study the molecular basis of the movement bulk fluid and neutral solutes in glands with the recent identification of two water channels (aquaporins, AQPs) in a tick salivary gland EST project. Sequence analysis indicates these two AQPs are likely to also transport urea and glycerol, be inhibited to sulfhydryl agents and be phosphorylated following gland stimulation. Of particular note, is the extremely unusual NPI instead of NPA motif and the consequences for solute permeability. The overall aim of the project is to characterise two aquaporins (AQPs, water-channels) identified in Rhipicephalus sanguineus salivary glands to give further insight into their importance in saliva production and tick feeding. The specific objectives are: 1. To assess the solute transporting properties of the two tick AQPs in the xenopus laevis oocyte expression system, namely water, glycerol and urea by video microscopy and radiotracer studies. The effect of site-directed mutagenic change of the NPI to NPA on solute transport will also be assessed. 2. to assess the temporal and tissue distribution of the two tick AQPs in R. sanguineus at mRNA transcript and protein level by real-time PCR and immunolocalisation immunoblotting, respectively, and to study the induction of these AQPs and their possible dopamine-induced incorporation of 32P. 3. Employing RNA interference, the function and importance of the two AQPs will be assessed with respect to tick feeding success and saliva production. Saliva composition (osmolarity, electrolyte, urea and anticoagulant content) will be assessed by HPLC-inductively coupled plasma-mass spectrometry, LC-MS and thrombin inhibition studies.

Summary

unavailable

Committee	Closed Committee - Animal Sciences (AS)
Research Topics	Animal Health
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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