PubAg

Main content area

Identification and characterization of an esterase involved in malathion resistance in the head louse Pediculus humanus capitis

Author:
Kwon, Deok Ho, Kim, Ju Hyeon, Kim, Young Ho, Yoon, Kyong Sup, Clark, J. Marshall, Lee, Si Hyeock
Source:
Pesticide biochemistry and physiology 2014 v.112 pp. 13-18
ISSN:
0048-3575
Subject:
Pediculus humanus capitis, RNA interference, carboxylesterase, complementary DNA, gene duplication, genes, malathion, nucleotide sequences, phylogeny, single nucleotide polymorphism, transcription (genetics)
Abstract:
Enhanced malathion carboxylesterase (MCE) activity was previously reported to be involved in malathion resistance in the head louse Pediculus humanus capitis (Gao et al., 2006 [8]). To identify MCE, the transcriptional profiles of all five esterases that had been annotated to be catalytically active were determined and compared between the malathion-resistant (BR-HL) and malathion-susceptible (KR-HL) strains of head lice. An esterase gene, designated HLCbE3, exhibited approximately 5.4-fold higher transcription levels, whereas remaining four esterases did not exhibit a significant increase in their transcription in BR-HL, indicating that HLCbE3 may be the putative MCE. Comparison of the entire cDNA sequences of HLCbE3 revealed no sequence differences between the BR-HL and KR-HL strains and suggested that no single nucleotide polymorphism is associated with enhanced MCE activity. Two copies of the HLCbE3 gene were observed in BR-HL, implying that the over-transcription of HLCbE3 is due to the combination of a gene duplication and up-regulated transcription. Knockdown of HLCbE3 expression by RNA interference in the BR-HL strain led to increases in malathion susceptibility, confirming the identity of HLCbE3 as a MCE responsible for malathion resistance in the head louse. Phylogenetic analysis suggested that HLCbE3 is a typical dietary esterase and belongs to a clade containing various MCEs involved in malathion resistance.
Agid:
5404524