AUTHOR=Li Dan , Liu Lei , Liu Zi-ling , Tian Yuan , Gao Xin , Cheng Tian-yin 

TITLE=What are the main proteins in the hemolymph of Haemaphysalis flava ticks?

JOURNAL=Frontiers in Veterinary Science

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2024.1387719

DOI=10.3389/fvets.2024.1387719

ISSN=2297-1769

ABSTRACT=<sec id="sec1"><title>Background</title><p><italic>Haemaphysalis flava</italic> is a notorious parasite for humans and animals worldwide. The organs of <italic>H. flava</italic> are bathed in hemolymph, which is a freely circulating fluid. Nutrients, immune factors, and waste can be transported to any part of the body via hemolymph. The main soluble components in hemolymph are proteins. However, knowledge of the <italic>H. flava</italic> proteome is limited.</p></sec><sec id="sec2"><title>Methods</title><p>The hemolymph was collected from fully engorged <italic>H. flava</italic> ticks by leg amputation. Hemolymph proteins were examined by both blue native polyacrylamide gel electrophoresis (BN-PAGE) and sodium dodecyl sulfate PAGE (SDS-PAGE). Proteins extracted from the gels were further identified by liquid chromatography–tandem mass spectrometry (LC–MS/MS).</p></sec><sec id="sec3"><title>Results</title><p>Two bands (380 and 520 kDa) were separated from tick hemolymph by BN-PAGE and were further separated into four bands (105, 120, 130, and 360 kDa) by SDS-PAGE. LC–MS/MS revealed that seven tick proteins and 13 host proteins were present in the four bands. These tick proteins mainly belonged to the vitellogenin (Vg) family and the α-macroglobulin family members. <italic>In silico</italic> structural analysis showed that these Vg family members all had common conserved domains, including the N-terminus lipid binding domain (LPD-N), the C-terminus von Willebrand type D domain (vWD), and the domain of unknown function (DUF). Additionally, two of the Vg family proteins were determined to belong to the carrier protein (CP) by analyzing the unique N-terminal amino acid sequences and the cleaving sites.</p></sec><sec id="sec4"><title>Conclusion</title><p>These findings suggest that the Vg family proteins and α-macroglobulin are the primary constituents of the hemolymph in the form of protein complexes. Our results provide a valuable resource for further functional investigations of <italic>H. flava</italic> hemolymph effectors and may be useful in tick management.</p></sec>