Cuticular lipids as a first barrier defending ixodid ticks against fungal infection
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2022
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Resumo
The chemical composition of tick cuticles acts as a barrier to pathogens and may limit
infection by entomopathogenic fungi. This study characterized the cuticular neutral lipids (NL) and
hydrocarbons (HCs) of four ixodid ticks that are widely distributed in Brazil. HC extracts were
analyzed by gas chromatography-mass spectrometry and used to challenge Beauveria bassiana IP361
and Metarhizium robertsii IP146; the effect of cuticular extracts in fungal growth were evaluated by
disk diffusion and conidial viability assays. In addition, conidial germination on the tick cuticle was
evaluated by scanning electron microscopy, and NL from ticks treated with fungi were assessed by
thin layer chromatography. Six HCs were exclusively identified in Amblyomma sculptum. Additionally,
cuticle extracts from Dermacentor nitens and A. sculptum inhibited the growth of M. robertsii IP146 and
reduced conidial germination of B. bassiana IP361 to 70% and 49%, respectively; the same extracts also
produced cytotoxic effects, with conidial death above 30% and 60%. Electron micrographs showed a
delayed germination of conidia incubated for 48 h or 72 h on D. nitens and A. sculptum. The lipid
profile of A. sculptum treated with fungi was not significantly altered; triacylglycerol was not detected
in the cuticle extracts of any other tick species. Finally, A. sculptum and D. nitens cuticles have lipid
components that may limit the development of M. robertsii.
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Entomopathogenic fungi, Rhipicephalus microplus, Amblyomma sculptum, Dermacentor nitens, Rhipicephalus sanguineus, Llipids, Hydrocarbons, Biological control
Citação
RIBEIRO-SILVA, Cárita S. et al. Cuticular lipids as a first barrier defending ixodid ticks against fungal infection. Journal of Fungi, Basel, v. 8, n. 11, p. 1177, 2022. DOI: 10.3390/jof8111177. Disponível em: https://www.mdpi.com/2309-608X/8/11/1177. Acesso em: 10 dez. 2024.