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Saliva, Salivary Gland, and Hemolymph Collection from Ixodes scapularis Ticks
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Hemolymph defensin from the hard tick Haemaphysalis longicornis attacks Gram-positive bacteria

Yurika Yada1, Melbourne Rio Talactac2, Kodai Kusakisako3

  • 1Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.

Journal of Invertebrate Pathology
|July 14, 2018
PubMed

Insights

Tick defensins, like HEdefensin, are crucial for innate immunity. This study shows HEdefensin combats Gram-positive bacteria by increasing membrane permeability, aiding tick survival against pathogens.

Area of Science:

  • Veterinary Entomology
  • Immunology
  • Molecular Biology

Background:

  • Ticks transmit diseases to humans and animals.
  • Ticks possess innate immunity to survive infections.
  • Antimicrobial peptides, including defensins, are key immune components.

Purpose of the Study:

  • To identify and characterize a novel tick defensin, HEdefensin, from Haemaphysalis longicornis.
  • To investigate the antibacterial activity and mechanism of HEdefensin.

Main Methods:

  • Gene cloning and sequencing of HEdefensin.
  • Synthesis and testing of HEdefensin against bacteria.
  • Propidium iodide exclusion assay to assess membrane permeability.
  • Indirect fluorescent antibody test to confirm peptide binding.

Main Results:

  • HEdefensin gene successfully cloned and sequenced.
  • Synthetic HEdefensin exhibited antibacterial activity against Gram-positive bacteria (Micrococcus luteus).
  • HEdefensin increased M. luteus membrane permeability.
  • HEdefensin demonstrated binding to M. luteus.

Conclusions:

  • HEdefensin is a functional antimicrobial peptide in ticks.
  • HEdefensin contributes to tick innate immunity against Gram-positive bacteria.
  • The mechanism involves disruption of bacterial membrane permeability.
Keywords:
BacteriaDefensinHaemaphysalis longicornis

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