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United States Department of Agriculture

Agricultural Research Service

Research Project: Cattle Fever Tick Control and Eradication

Location: Livestock Arthropod Pest Research

Title: Functional and morphological analysis of putative chemoreception-related proteins in the lone star tick, Amblyomma americanum

item Trivedi, P
item Das, T
item Bach, S
item Seshu, J
item Lohmeyer, Kimberly - Kim
item Perez De Leon, Adalberto - Beto
item Renthal, R

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/19/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Ehrlichiosis, a potentially fatal infection, is caused by rickettsial bacteria transmitted by the lone star tick, Amblyomma americanum. We previously analyzed the chemosensory appendage proteome of A. americanum as part of a project to develop new chemosensory-based vector control methods. Among the chemosensory-related proteins we identified were OBPL1 and OBPL2, predicted to be similar to insect odorant-binding proteins. The A. americanum OBPL1 sequence was incomplete, but the full-length sequence of a highly similar protein was found in the Ixodes scapularis genome. We have now expressed I. scapularis OBPL1 and A. americanum OBPL2 in E. coli and measured the binding of the purified proteins to N-phenylnaphthylamine (NPN), a hydrophobic fluorescent dye known to interact strongly with insect odorant-binding proteins. Both OBPL1 and OBPL2 showed strong, saturable binding to NPN, indicating the presence of a discrete hydrophobic ligand-binding pocket. We also used imaging mass spectrometry to identify proteins in the region of the olfactory Haller's organ on the A. americanum fore tarsus. A protein with a mass-to-charge ratio (m/z) close to 9300 was found uniquely in the vicinity of the DI.1 sensilla, distal to the anterior pit sensilla. One of the most abundant chemosensory-related proteins we previously detected in the fore tarsus proteome was a microplusin-like protein called ML1, with an expected m/z of 9302. This indicates that ML1 could be involved in the olfactory activity of the DI.1 sensilla.

Last Modified: 09/21/2017
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