Comparison of the genome profiles between head and body lice

Kang, J.S.,Cho, Y.J.,Kim, J.H.,Kim, S.H.,Yoo, S.,Noh, S.J.,Park, J.,Yoon, K.S.,Marshall Clark, J.,Pittendrigh, B.R.,Chun, J.,Lee, S.H. 한국응용곤충학회 2015 Journal of Asia-Pacific Entomology Vol.20 No.3

The body louse (Pediculus humanus humanus) is known to have diverged from the head louse (P. humanus capitis) but genomic differences between these two subspecies still remain unexplored. To compare genomic profiles between head and body lice, whole genome sequences of head lice were determined by next generation sequencing methods based on both Illumina Genome analyzer and Roche GS FLX pyrosequencing and compared with the reference genome sequences of the body louse. Total consensuses generated by mapping to the body louse genome in conjunction with de novo assembly of head louse genome sequences revealed a head louse genome size of 110Mbp with a 96% coverage of the body louse genome sequences. A total of 12,651 genes were predicted from the head louse genome sequences although more precise assembly and functional annotation of the genome is required for a more accurate gene count. Among the 873 genes that were putatively specific to the head louse, 15 genes were confirmed to be transcribed in both head and body lice, suggesting the previously estimated gene number of the body louse was likely underestimated. The single nucleotide polymorphism analysis showed that the nucleotide diversity of genome between head and body lice was 2.2%, which was larger than that of the transcriptome between head and body lice. An endosymbiont genome analysis showed that the composition of endosymbionts in head lice was similar to that of body lice and Candidatus Riesia pediculicola was the primary endosymbiont in both head and body lice.

Determination, mechanism and monitoring of knockdown resistance in permethrin-resistant human head lice, Pediculus humanus capitis

J. Marshall Clark 한국응용곤충학회 2009 Journal of Asia-Pacific Entomology Vol.12 No.1

Permethrin resistance has been reported worldwide and clinical failures to commercial pediculicides containing permethrin have likewise occurred. Permethrin resistance in head lice populations from the U.S. is widespread but is not yet uniform and the level of resistance is relatively low (∼4–8 fold). Permethrinresistant lice are cross-resistant to pyrethrins, PBO-synergized pyrethrins and to DDT. Nix®, when applied to human hair tufts following manufacturer's instructions, did not provide 100% control when assessed by the hair tuft bioassay in conjunction with the in vitro rearing system. Resistance to permethrin is due to knockdown resistance (kdr), which is the result of three point mutations within the α-subunit gene of the voltage-gated sodium channel that causes amino acid substitutions, leading to nerve insensitivity. A three-tiered resistance monitoring system has been established based on molecular resistance detection techniques. Quantitative sequencing (QS) has been developed to predict the kdr allele frequency in head lice at a population level. The speed, simplicity and accuracy of QS made it an ideal candidate for a routine primary resistance monitoring tool to screen a large number of louse populations as an alternative to conventional bioassay. As a secondary monitoring method, real-time PASA (rtPASA) has been devised for a more precise determination of low resistance allele frequencies. To obtain more detailed information on resistance allele zygosity, as well as allele frequency, serial invasive signal amplification reaction (SISAR) has been developed as an individual genotyping method. Our approach of using three tiers of molecular resistance detection should facilitate large-scale routine resistance monitoring of permethrin resistance in head lice using field-collected samples. Permethrin resistance has been reported worldwide and clinical failures to commercial pediculicides containing permethrin have likewise occurred. Permethrin resistance in head lice populations from the U.S. is widespread but is not yet uniform and the level of resistance is relatively low (∼4–8 fold). Permethrinresistant lice are cross-resistant to pyrethrins, PBO-synergized pyrethrins and to DDT. Nix®, when applied to human hair tufts following manufacturer's instructions, did not provide 100% control when assessed by the hair tuft bioassay in conjunction with the in vitro rearing system. Resistance to permethrin is due to knockdown resistance (kdr), which is the result of three point mutations within the α-subunit gene of the voltage-gated sodium channel that causes amino acid substitutions, leading to nerve insensitivity. A three-tiered resistance monitoring system has been established based on molecular resistance detection techniques. Quantitative sequencing (QS) has been developed to predict the kdr allele frequency in head lice at a population level. The speed, simplicity and accuracy of QS made it an ideal candidate for a routine primary resistance monitoring tool to screen a large number of louse populations as an alternative to conventional bioassay. As a secondary monitoring method, real-time PASA (rtPASA) has been devised for a more precise determination of low resistance allele frequencies. To obtain more detailed information on resistance allele zygosity, as well as allele frequency, serial invasive signal amplification reaction (SISAR) has been developed as an individual genotyping method. Our approach of using three tiers of molecular resistance detection should facilitate large-scale routine resistance monitoring of permethrin resistance in head lice using field-collected samples.

Expansion of the Knockdown Resistance Frequency Map for Human Head Lice (Phthiraptera: Pediculidae) in the United States Using Quantitative Sequencing

Gellatly, Kyle J.,Krim, Sarah,Palenchar, Daniel J.,Shepherd, Katie,Yoon, Kyong Sup,Rhodes, Christopher J.,Lee, Si Hyeock,Marshall Clark, J. Oxford University Press 2016 Journal of medical entomology Vol.53 No.3

<P>Pediculosis is a prevalent parasitic infestation of humans, which is increasing due, in part, to the selection of lice resistant to either the pyrethrins or pyrethroid insecticides by the knockdown resistance (<I>kdr</I>) mechanism. To determine the extent and magnitude of the <I>kdr</I>-type mutations responsible for this resistance, lice were collected from 138 collection sites in 48 U.S. states from 22 July 2013 to 11 May 2015 and analyzed by quantitative sequencing. Previously published data were used for comparisons of the changes in the frequency of the <I>kdr</I>-type mutations over time. Mean percent resistance allele frequency (mean % RAF) values across the three mutation loci were determined from each collection site. The overall mean % RAF (±SD) for all analyzed lice was 98.3 ± 10%. 132/138 sites (95.6%) had a mean % RAF of 100%, five sites (3.7%) had intermediate values, and only a single site had no mutations (0.0%). Forty-two states (88%) had a mean % RAF of 100%. The frequencies of <I>kdr</I>-type mutations did not differ regardless of the human population size that the lice were collected from, indicating a uniformly high level of resistant alleles. The loss of efficacy of the Nix formulation (Prestige Brand, Tarrytown, NY) from 1998 to 2013 was correlated to the increase in <I>kdr</I>-type mutations. These data provide a plausible reason for the decrease in the effectiveness of permethrin in the Nix formulation, which is the parallel increase of <I>kdr</I>-type mutations in lice over time.</P>

Estimation of Knockdown Resistance in Diamondback Moth Using Real-time PASA

Deok Ho Kwon,J. Marshall Clark,Si Hyeock Lee 한국농약과학회 2003 한국농약과학회 학술발표대회 논문집 Vol.- No.-

Cross-strain comparison of cypermethrin-induced cytochrome P450 transcription under different induction conditions in diamondback moth

Baek, Ji Hyeong,Clark, J. Marshall,Lee, Si Hyeock Elsevier 2010 Pesticide biochemistry and physiology Vol.96 No.1

<P><B>Abstract</B></P><P>Synergism with piperonyl butoxide indicated that enhanced P450 activity is likely associated with pyrethroid resistance in an isogenic cypermethrin-resistant (CR) strain of diamondback moth (DBM), <I>Plutella xylostella</I> (L.). Eleven P450 genes, including 8 novel ones, were cloned from DBM, and their basal and cypermethrin-induced transcription levels were compared between insecticide-susceptible (Sus) and CR strains. One P450 gene was determined to be constitutively overtranscribed in CR strain. To determine the conditions resulting in maximum levels of P450 gene induction by cypermethrin, several factors, including routes of insecticide administration (topical vs. leaf dip), exposure amounts and durations of exposure, were examined. In general, the leaf dip method resulted in greater levels of induction in a wider array of P450 genes. The conditions of ‘low sub-lethal amounts and short exposures’ to cypermethrin were more efficient in P450 induction than those of ‘high amounts (e.g., LD<SUB>50</SUB> or LC<SUB>50</SUB>) and long exposures’. Cross-strain comparisons revealed that 8 of 11 P450 genes were induced (1.5- to 2.2-fold) in CR larvae whereas only a single P450 gene was induced in Sus larvae under optimal induction conditions. This finding demonstrates that selective P450 gene induction by cypermethrin in addition to constitutive overexpression can confer metabolic resistance in the CR strain. Current study also provides a framework for future induction experiments for the transcriptional profiling of insect detoxification genes in response to insecticide exposure.</P>

Comparison of Immune Responses between Human Body and Head Louse: Insights into Vector Competence Difference

Ju Hyeon Kim,Domenic J. Previte,Kyung Jae Yoon,Kyung Mun Kim,Edwin Murenzi,Kyong Sup Yoon,J. Marshall Clark,Si Hyeock Lee 한국응용곤충학회 2016 한국응용곤충학회 학술대회논문집 Vol.2016 No.04

Human body and head lice are obligatory human ectoparasites. Although both body and head lice belong to a single species, Pediculus humanus, only body lice are known to be a vector of several bacterial diseases. The higher vector competence of body lice is assumed to be due to their weaker immune response than that of head lice. To test this hypothesis, immune reactions were compared between body and head lice following infections by two model bacteria, Staphylococcus aureus and Escherichia coli, and a human pathogen, Bartonella quintana. Following dermal or oral challenge, the number of these bacteria increased both in hemocoel and alimentary tract of body lice but not in head lice and the viability of the B. quintana was significantly higher in body louse feces, the major route of infection to human. In addition, body lice showed the lower basal/induced transcription level of major immune genes, cytotoxic reactive oxygen species and phagocytosis activity compared with head lice. These findings suggest that a reduced immune response may be responsible, in part, for the increased proliferation and excretion of viable bacteria which are associated with the high level of human infectivity seen in body versus head lice.

Genomics of Body/Head Lice and Its Application

Si Hyeock Lee,Ju Hyeon Kim,J. Marshall Clark,Barry B. Pittendrigh 한국응용곤충학회 2014 한국응용곤충학회 학술대회논문집 Vol.2014 No.04

Both the body louse (Pediculus humanus humanus) and the head louse (P. humanus capitis) are obligatory human ectoparasites. The body louse is a serious public health threat because it transmits a variety of human diseases whereas the head lice causes one of the most prevalent human infestations, pediculosis. Recent genome analysis revealed that both body and head lice have one of the smallest insect genomes (~108 Mb). Comparison of transcriptional profiles uncovered that almost the same number of genes was annotated both in the head louse (10,770 genes) and the body louse (10,771 genes) among 10,775 protein-coding genes predicted from the body louse genome. Despite their similar genetic background, body and head lice have several differences in their biological features, such as choice of habitat on human host, body size and vector competence. Annotation of major detoxification genes revealed that they are dramatically reduced in human lice compared to other insects except for the honey bee and that, despite the overall reduction in number, human lice retain at least a minimum repertoire of genes known to confer metabolic or toxicokinetic resistance to insecticides, suggesting their high potential for resistance development. Comparison of insecticide target site gene sequences and transcription levels of detoxification genes enabled the identification of toxicodynamic and metabolic factors of insecticide resistance and further allowed the development of molecular markers for resistance detection. Transcriptional profiling during tolerance was used to identify ivermectinmetabolizing detoxification genes, indicating that such an approach may allow proactive resistance management. Comparison of genomes and transcriptomes between body and head lice suggested that vector competence difference is not attributed to the difference in the composition of immune related genes but rather to their transcriptional regulation and/or not-yet-identified epigenetic factors.

A point mutation in a glutamate-gated chloride channel confers abamectin resistance in the two-spotted spider mite, Tetranychus urticae Koch

Deok Ho Kwon,Kyong Sup Yoon,J. Marshall Clark,Si Hyeock Lee 한국응용곤충학회 2010 한국응용곤충학회 학술대회논문집 Vol.2010 No.05

The molecular mechanisms and genetics of abamectin resistance mediated by target site insensitivity in the two-spotted spider mite, Tetranychus urticae, were investigated by comparing two isogenic AbaS and AbaR strains. Cloning and sequencing of full-length cDNA fragments of GABA-gated chloride channel genes revealed no polymorphisms between the two strains. However, sequence comparison of the full-length cDNA fragment of a T. urticae glutamate-gated chloride channel gene (TuGluCl) identified a G323D point mutation as being tentatively related with abamectin resistance. In individual F2 progenies obtained by backcrossing, the G323D genotype was confirmed to correlate with abamectin resistance. Bioassays using progeny from reciprocal crossings revealed that the abamectin resistance trait due to TuGluCl insensitivity is incompletely recessive.

Comparison of the immune response in alimentary tract tissues from body versus head lice following Escherichia coli oral infection

Ju Hyeon Kim,Kyong Sup Yoon,Domenic J. Previte,Barry R. Pittendrigh,J. Marshall Clark,이시혁 한국응용곤충학회 2012 Journal of Asia-Pacific Entomology Vol.15 No.3

Human body and head lice have been hematophagous ectoparasites of humans for thousands of years. Although both body and head lice belong to a single species, Pediculus humanus, only body lice are known to transmit several bacterial diseases to humans. This difference in vector competence is assumed to be due to their different immune responses. Here, the immune reactions in the alimentary tract were investigated in both body and head lice following oral challenge of Escherichia coli as a model Gram-negative bacterium. In proliferation assay, head lice suppressed the growth of E. coli effectively at the early stage of infection,resulting in gradual reduction of E. coli number in alimentary tract tissues. In contrast, the number of E. coli steadily increased in alimentary tract tissues of body lice. No apparent alteration of transcription was observed following E. coli challenge in three important genes for the humoral immune responses, peptidoglycan recognition protein as a recognition gene and defensin 1 and defensin 2 as effector genes. Nevertheless, the basal transcription levels of these genes were higher in the gut tissues of body versus head lice. Considering that there is no cellular immune reaction in gut tissues, these findings suggest that the higher constitutive transcription levels of major immune genes in head lice can contribute to their rapid defense and enhanced immune capacity against intestinal bacterial infection.

Transcriptome profiling of the diamondback moth treated with sublethal doses of five different insecticides and characterization of commonly responding genes

Yue Gao,Kyungmun Kim,Deok Ho Kwon,In Hong Jeong,J. Marshall Clark,Si Hyeock Lee 한국농약과학회 2017 한국농약과학회 학술발표대회 논문집 Vol.2017 No.11