Neuropeptides in Rhipicephalus microplus and other hard ticks

Area of Science:

• Neurobiology
• Tick Physiology
• Molecular Biology

Background:

• The synganglion, the tick's central nervous system, regulates physiology via signaling molecules, primarily neuropeptides.
• The precise functions of many tick neuropeptides remain largely uncharacterized.

Purpose of the Study:

• To identify and characterize neuropeptides in Rhipicephalus microplus across various life stages and organs.
• To investigate the abundance and potential roles of neuropeptides in tick neurobiology.

Main Methods:

• Transcriptome generation from multiple tick organs (ovary, salivary glands, fat body, midgut, embryo).
• In silico annotation and characterization of synganglion transcripts.
• Prediction of mature neuropeptides from precursor sequences using comparative analysis.

Main Results:

• Identification of 32 functional protein categories in the synganglion, with secreted, energetic, and oxidant metabolism proteins being most abundant.
• Discovery of 52 neuropeptide precursors, with significantly higher transcription in the synganglion compared to other tissues.
• Identification of several neuropeptides not previously reported in ticks, such as ETH, and confirmation of widespread presence across tick species.

Conclusions:

• Neuropeptide precursors are significantly over-represented in the tick synganglion, indicating a crucial role in tick neurophysiology.
• The identified neuropeptides, including novel ones, are largely conserved across tick species.
• Characterizing neuropeptide functions and receptors offers potential avenues for developing novel tick control strategies and drug targets.