Molecular Monitoring of Knockdown Resistance in Head Louse (Phthiraptera: Pediculidae) Populations in Iran

Abstract Knockdown resistance (kdr) is a common mechanism of insecticide resistance in head lice to the conventionally used pyrethroid pediculosis and can be the result of various amino acid substitutions within the voltage-sensitive sodium channel (VSSC). In this study, 54 sequences from varied specimens were investigated to monitor well-known resistance mutations and probable new mutations. The Pediculus humanus capitis de Geer specimens were collected from 13 provinces in Iran. The specimens were stored in 70% ethanol until DNA extraction and PCR amplification of ~900-bp fragment of VSSC. The sequences were analyzed using different bioinformatics software for the detection of well-known kdr substitutions and additional mutations potentially associated with kdr resistance in head lice. There were six new and an old (haplotype I) kdr haplotypes within the Iranian head louse population. K794E, F815I, and N818D amino acid substitutions were reported for the first time. The P813H mutation was the most prevalent amino acid substitution in eight provinces. Among 53 sequences, 26 (49%) were homozygous susceptible, and 27 (51%) were heterozygotes. Thus, 51% of the head lice collected in Iran harbored only the P813H allele. The exact test for the Hardy–Weinberg (H–W) equilibrium showed that genotype frequencies differed significantly from the expectation in East-Azerbaijan and Tehran provinces. Moreover, these populations had an inbreeding coefficient (Fis) <0, indicating the excess of heterozygotes. This observation suggests that the populations of head lice from Iran are currently under active selective pressure. For the rest of the populations, H–W equilibrium and the expectations were significantly in harmony. The results of the current study highlight molecular techniques in the accurate detection of resistance genotypes before their establishment within the head louse population. Accurate detection of resistant genotypes seems to be helpful in decision-making on lice control programs and resistance monitoring and management.

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Genotypic and Phenotypic Analyses of Hepatitis C Virus from Patients Treated with JTK-853 in a Three-Day Monotherapy

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01432-12 ◽

2012 ◽

Vol 57 (1) ◽

pp. 436-444 ◽

Cited By ~ 1

Author(s):

Naoki Ogura ◽

Yukiyo Toyonaga ◽

Izuru Ando ◽

Kunihiro Hirahara ◽

Tsutomu Shibata ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Amino Acid ◽

Viral Resistance ◽

Hcv Rna ◽

Amino Acid Substitutions ◽

Sequencing Analysis ◽

Resistance Mutations ◽

In The Wild

ABSTRACTJTK-853, a palm site-binding NS5B nonnucleoside polymerase inhibitor, shows antiviral activityin vitroand in hepatitis C virus (HCV)-infected patients. Here, we report the results of genotypic and phenotypic analyses of resistant variants in 24 HCV genotype 1-infected patients who received JTK-853 (800, 1,200, or 1,600 mg twice daily or 1,200 mg three times daily) in a 3-day monotherapy. Viral resistance in NS5B was investigated using HCV RNA isolated from serum specimens from the patients. At the end of treatment (EOT) with JTK-853, the amino acid substitutions M414T (methionine [M] in position 414 at baseline was replaced with threonine [T] at EOT), C445R (cysteine [C] in position 445 at baseline was replaced with arginine [R] at EOT), Y448C/H (tyrosine [Y] in position 448 at baseline was replaced with cysteine [C] or histidine [H] at EOT), and L466F (leucine [L] in position 466 at baseline was replaced with phenylalanine [F] at EOT), which are known to be typical resistant variants of nonnucleoside polymerase inhibitors, were observed in a clonal sequencing analysis. These substitutions were also selected by a treatment with JTK-853in vitro, and the 50% effective concentration of JTK-853 in the M414T-, C445F-, Y448H-, and L466V-harboring replicons attenuated the susceptibility by 44-, 5-, 6-, and 21-fold, respectively, compared with that in the wild-type replicon (Con1). These findings suggest that amino acid substitutions of M414T, C445R, Y448C/H, and L466F are thought to be viral resistance mutations in HCV-infected patients receiving JTK-853 in a 3-day monotherapy.

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Presence of the knockdown resistance (kdr) mutations in the head lice (Pediculus humanus capitis) collected from primary school children of Thailand

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0008955 ◽

2020 ◽

Vol 14 (12) ◽

pp. e0008955

Author(s):

Narisa Brownell ◽

Sakone Sunantaraporn ◽

Kobpat Phadungsaksawasdi ◽

Nirin Seatamanoch ◽

Switt Kongdachalert ◽

...

Keyword(s):

Head Louse ◽

Point Mutations ◽

Human Head ◽

Amino Acid Sequences ◽

Primary School Children ◽

Head Lice ◽

Knockdown Resistance ◽

Pediculosis Capitis ◽

Α Subunit ◽

Blood Sucking

Human head lice are blood-sucking insects causing an infestation in humans called pediculosis capitis. The infestation is more prevalent in the school-aged population. Scalp itching, a common presenting symptom, results in scratching and sleep disturbance. The condition can lead to social stigmatization which can lead to loss of self-esteem. Currently, the mainstay of treatment for pediculosis is chemical insecticides such as permethrin. The extended use of permethrin worldwide leads to growing pediculicide resistance. The aim of this study is to demonstrate the presence of the knockdown resistance (kdr) mutation in head lice populations from six different localities of Thailand. A total of 260 head lice samples in this study were collected from 15 provinces in the 6 regions of Thailand. Polymerase chain reaction (PCR) was used to amplify the α subunit of voltage-sensitive sodium channel (VSSC) gene, kdr mutation (C→T substitution). Restriction fragment length polymorphism (RFLP) patterns and sequencing were used to identify the kdr T917I mutation and demonstrated three genotypic forms including homozygous susceptible (SS), heterozygous genotype (RS), and homozygous resistant (RR). Of 260 samples from this study, 156 (60.00%) were SS, 58 (22.31%) were RS, and 46 (17.69%) were RR. The overall frequency of the kdr T917I mutation was 0.31. Genotypes frequencies determination using the exact test of Hardy-Weinberg equilibrium found that northern, central, northeastern, southern, and western region of Thailand differed from expectation. The five aforementioned localities had positive inbreeding coefficient value (Fis > 0) which indicated an excess of homozygotes. The nucleotide and amino acid sequences of RS and RR showed T917I and L920F point mutations. In conclusion, this is the first study detecting permethrin resistance among human head lice from Thailand. PCR-RFLP is an easy technique to demonstrate the kdr mutation in head louse. The data obtained from this study would increase awareness of increasing of the kdr mutation in head louse in Thailand.

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Macrolide and fluoroquinolone associated mutations in Mycoplasma genitalium in a retrospective study of male and female patients seeking care at an STI Clinic in Guangzhou, China, 2016-2018.

10.21203/rs.3.rs-19555/v4 ◽

2020 ◽

Author(s):

Wujian Ke ◽

Dongling Li ◽

Lai Sze Tso ◽

Ran Wei ◽

Yinyuan Lan ◽

...

Keyword(s):

Amino Acid ◽

Antimicrobial Resistance ◽

Fluoroquinolone Resistance ◽

23S Rrna ◽

Resistance Testing ◽

Rrna Gene ◽

Amino Acid Substitutions ◽

Resistance Mutations ◽

Topoisomerase Iv ◽

Two Samples

Abstract Background Antimicrobial resistance in M. genitalium is a growing clinical problem. We investigated the mutations associated with macrolide and fluoroquinolone resistance, two commonly used medical regimens for treatment in China. Our aim is to analyze the prevalence and diversity of mutations among M. genitalium-positive clinical specimens in Guangzhou, south China.Methods A total of 154 stored M. genitalium positive specimens from men and women attending a STI clinic were tested for macrolide and fluoroquinolone mutations. M. genitalium was detected via TaqMan MGB real-time PCR. Mutations associated with macrolide resistance were detected using primers targeting region V of the 23S rRNA gene. Fluoroquinolone resistant mutations were screened via primers targeting topoisomerase IV (parC) and DNA gyrase (gyrA).Results 98.7% (152/154), 95.5% (147/154) and 90.3% (139/154) of M. genitalium positive samples produced sufficient amplicon for detecting resistance mutations in 23S rRNA, gyrA and parC genes, respectively. 66.4% (101/152), 0.7% (1/147) and 77.7% (108/139) samples manifested mutations in 23S rRNA, gyrA and parC genes, respectively. A2072G (59/101, 58.4%) and S83I (79/108, 73.1%) were highly predominating in 23S rRNA and parC genes, respectively. Two samples had amino acid substitutions in gyrA (M95I and A96T, respectively). Two samples had two amino acid substitutions in parC (S83I + D87Y). 48.6% (67/138) of samples harbored both macrolide and fluoroquinolone resistance-associated mutations. The most common combination of mutations was A2072G (23S rRNA) and S83I (parC) (40/67, 59.7%). One sample had three amino acid changes in 23S rRNA, gyrA and parC genes (A2072G + A96T + S83I).Conclusions The high antimicrobial resistance rate of M. genitalium in Guangzhou is a very worrying problem and suggests that antimicrobial resistance testing and the development of new antibiotic regimens are crucially needed.

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Hepatitis C Virus RNA Elimination and Development of Resistance in Replicon Cells Treated with BMS-790052

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05977-11 ◽

2012 ◽

Vol 56 (3) ◽

pp. 1350-1358 ◽

Cited By ~ 44

Author(s):

Chunfu Wang ◽

Haichang Huang ◽

Lourdes Valera ◽

Jin-Hua Sun ◽

Donald R. O'Boyle ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Amino Acid ◽

Nonstructural Protein ◽

Single Amino Acid ◽

Amino Acid Substitutions ◽

Dependent Manner ◽

Resistance Mutations ◽

Genotype 1A ◽

Clinical Resistance

ABSTRACTBMS-790052, a first-in-class hepatitis C virus (HCV) replication complex inhibitor, targeting nonstructural protein 5A (NS5A), displays picomolar to nanomolar potency against genotypes 1 to 5. This exceptional potency translated into robust anti-HCV activity in clinical studies with HCV genotype 1-infected subjects. To date, all BMS-790052-associated resistance mutations have mapped to the N-terminal region of NS5A. To further characterize the antiviral activity of BMS-790052, HCV replicon elimination and colony formation assays were performed. Replicon was cleared from genotype 1a and 1b replicon cells in a time- and dose-dependent manner. Elimination of the genotype 1a replicon required longer treatment durations and higher concentrations of BMS-790052 than those for the genotype1b replicon. Single amino acid substitutions that conferred relatively low levels of resistance were observed at early time points and at low doses. Higher doses and longer treatment durations yielded mutations that conferred greater levels of resistance, including linked amino acid substitutions. Replicon cells that survived inhibitor treatment remained fully sensitivity to pegylated alpha interferon (pegIFN-α) and other HCV inhibitors. Moreover, genotype 1a replicon elimination was markedly enhanced when pegIFN-α and BMS-790052 were combined. Resistant variants observed in this study were very similar to those observed in a multiple ascending dose (MAD) monotherapy trial of BMS-790052, validating replicon elimination studies as a model to predict clinical resistance. Insights gained from thein vitroanti-HCV activity and resistance profiles of BMS-790052 will be used to help guide the clinical development of this novel HCV inhibitor.

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Macrolide and fluoroquinolone associated mutations in Mycoplasma genitalium in a retrospective study of male and female patients seeking care at an STI Clinic in Guangzhou, China, 2016-2018.

10.21203/rs.3.rs-19555/v3 ◽

2020 ◽

Author(s):

Wujian Ke ◽

Dongling Li ◽

Lai Sze Tso ◽

Ran Wei ◽

Yinyuan Lan ◽

...

Keyword(s):

Amino Acid ◽

Antimicrobial Resistance ◽

Fluoroquinolone Resistance ◽

23S Rrna ◽

Resistance Testing ◽

Rrna Gene ◽

Amino Acid Substitutions ◽

Resistance Mutations ◽

Topoisomerase Iv ◽

Two Samples

Abstract BackgroundAntimicrobial resistance in M. genitalium is a growing clinical problem. We investigated the mutations associated with macrolide and fluoroquinolone resistance, two commonly used medical regimens for treatment in China. Our aim is to analyze the prevalence and diversity of mutations among M. genitalium-positive clinical specimens in Guangzhou, south China.MethodsA total of 154 stored M. genitalium positive specimens from men and women attending a STI clinic were tested for macrolide and fluoroquinolone mutations. M. genitalium was detected via TaqMan MGB real-time PCR. Mutations associated with macrolide resistance were detected using primers targeting region V of the 23S rRNA gene. Fluoroquinolone resistant mutations were screened via primers targeting topoisomerase IV (parC) and DNA gyrase (gyrA).Results98.7% (152/154), 95.5% (147/154) and 90.3% (139/154) of M. genitalium positive samples produced sufficient amplicon for detecting resistance mutations in 23S rRNA, gyrA and parC genes, respectively. 66.4% (101/152), 0.7% (1/147) and 77.7% (108/139) samples manifested mutations in 23S rRNA, gyrA and parC genes, respectively. A2072G (59/101, 58.4%) and S83I (79/108, 73.1%) were highly predominating in 23S rRNA and parC genes, respectively. Two samples had amino acid substitutions in gyrA (M95I and A96T, respectively). Two samples had two amino acid substitutions in parC (S83I + D87Y). 48.6% (67/138) of samples harbored both macrolide and fluoroquinolone resistance-associated mutations. The most common combination of mutations was A2072G (23S rRNA) and S83I (parC) (40/67, 59.7%). One sample had three amino acid changes in 23S rRNA, gyrA and parC genes (A2072G + A96T + S83I).ConclusionsThe high antimicrobial resistance rate of M. genitalium in Guangzhou is a very worrying problem and suggests that antimicrobial resistance testing and the development of new antibiotic regimens are crucially needed.

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Macrolide and fluoroquinolone associated mutations in Mycoplasma genitalium in a retrospective study of male and female patients seeking care at a STI Clinic in Guangzhou, China, 2016-2018.

10.21203/rs.3.rs-19555/v6 ◽

2020 ◽

Author(s):

Wujian Ke ◽

Dongling Li ◽

Lai Sze Tso ◽

Ran Wei ◽

Yinyuan Lan ◽

...

Keyword(s):

Amino Acid ◽

Antimicrobial Resistance ◽

Fluoroquinolone Resistance ◽

23S Rrna ◽

Resistance Testing ◽

Rrna Gene ◽

Amino Acid Substitutions ◽

Resistance Mutations ◽

Topoisomerase Iv ◽

Two Samples

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Mutations in elongation factor EF-1 alpha affect the frequency of frameshifting and amino acid misincorporation in Saccharomyces cerevisiae.

Genetics ◽

10.1093/genetics/120.4.923 ◽

1988 ◽

Vol 120 (4) ◽

pp. 923-934

Author(s):

M G Sandbaken ◽

M R Culbertson

Keyword(s):

Saccharomyces Cerevisiae ◽

Amino Acid ◽

Mutational Analysis ◽

Elongation Factor ◽

Common Mechanism ◽

Amino Acid Substitutions ◽

Protein Amino Acid ◽

Nonsense Mutations ◽

Reading Frame

Abstract A mutational analysis of the eukaryotic elongation factor EF-1 alpha indicates that this protein functions to limit the frequency of errors during genetic code translation. We found that both amino acid misincorporation and reading frame errors are controlled by EF-1 alpha. In order to examine the function of this protein, the TEF2 gene, which encodes EF-1 alpha in Saccharomyces cerevisiae, was mutagenized in vitro with hydroxylamine. Sixteen independent TEF2 alleles were isolated by their ability to suppress frameshift mutations. DNA sequence analysis identified eight different sites in the EF-1 alpha protein that elevate the frequency of mistranslation when mutated. These sites are located in two different regions of the protein. Amino acid substitutions located in or near the GTP-binding and hydrolysis domain of the protein cause suppression of frameshift and nonsense mutations. These mutations may effect mistranslation by altering the binding or hydrolysis of GTP. Amino acid substitutions located adjacent to a putative aminoacyl-tRNA binding region also suppress frameshift and nonsense mutations. These mutations may alter the binding of aminoacyl-tRNA by EF-1 alpha. The identification of frameshift and nonsense suppressor mutations in EF-1 alpha indicates a role for this protein in limiting amino acid misincorporation and reading frame errors. We suggest that these types of errors are controlled by a common mechanism or closely related mechanisms.

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Computational Analysis of the Sequences of LIPE Gene of Selected Ruminants and Non-ruminants

Journal of Advances in Biology & Biotechnology ◽

10.9734/jabb/2019/v22i330117 ◽

2019 ◽

pp. 1-10

Author(s):

Rasheed B. Fatai ◽

Mabel O. Akinyemi ◽

Osamede Henry Osaiyuwu

Keyword(s):

Amino Acid ◽

Protein Kinase ◽

Water Buffalo ◽

Nucleotide Sequences ◽

Molecular Techniques ◽

Farm Animals ◽

Mass Selection ◽

Amino Acid Substitutions ◽

Sequencing Analysis ◽

Single Nucleotide

Tropically adapted farm animals are characterized by low meat and milk productivity. Traditionally, mass selection has been widely employed in breeding for improved animal performance. However, improving animal productivity using mass selection is laborious and usually less effective. Advances in molecular techniques such as DNA sequencing analysis provide the opportunity to characterize meat and milk influencing genes, which can lead to faster genetic improvement but often unaffordable and expensive particularly in developing countries. Unlike the wet laboratory analysis, computational molecular analyses is comparatively cheaper in pre-screening of the functional impacts of nonsynonymous single-nucleotide variants of some performance traits-related genes such as hormone-sensitive lipase (LIPE). A total of fifteen (15) LIPE nucleotide sequences comprising pig (3), cattle (3), water buffalo (2), camel (2), goat (2) and sheep (3) were retrieved from the Genbank. Also, twenty (20) functionally associated genes with the LIPE gene including perilipin 1, 2 & 5 protein kinase cAMP-activated catalytic subunit alpha, protein kinase X-linked were determined using the GeneMANIA. Functional analysis of non-synonymous single nucleotide polymorphism using PROVEAN showed that ten amino acid substitutions (S216C, P107del, Q28_P29insRATHVA, S41_S44dup, A640M, S940A, L660I, D86delinsWA, S1000F) in water buffalo and pig (X678E, V789K, G987del, T218K, Q2234del, L278H, Q321del, L1023delinsPKL, P1452V, H1267delinsRFT), nine in sheep (F67_P68delinsVQ, R24G, A247_R248dup, L122L, L144P, S149K, S125S, S224H, G148M) and goats (A450Y, P480H, G490delinsPHQ, L500R, R550del, S100_S101dup, E600S, A700Q, P754delinsQAW) and five in camel (A320A, S210S, L130L, T400T, L440I) were found neutral indicating their beneficial effect while only T110A out of the fifteen amino acid substitutions was found deleterious in cattle. The obtained phylogenetic trees from the nucleotide sequences showed a closer relationship among the members of the Bovidae family particularly the sheep and cattle. This information may aid future research that aims at the selection of the studied animals for improved meat and milk quality traits.

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Toxin-resistant isoforms of Na + /K + -ATPase in snakes do not closely track dietary specialization on toads

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.2111 ◽

2016 ◽

Vol 283 (1842) ◽

pp. 20162111 ◽

Cited By ~ 19

Author(s):

Shabnam Mohammadi ◽

Zachariah Gompert ◽

Jonathan Gonzalez ◽

Hirohiko Takeuchi ◽

Akira Mori ◽

...

Keyword(s):

Amino Acid ◽

Food Source ◽

Binding Pocket ◽

Toxic Effects ◽

Amino Acid Substitutions ◽

Acute Effects ◽

Resistance Mutations ◽

Dietary Specialization ◽

Cardiotonic Steroid ◽

Steroid Binding

Toads are chemically defended by bufadienolides, a class of cardiotonic steroids that exert toxic effects by binding to and disabling the Na + /K + -ATPases of cell membranes. Some predators, including a number of snakes, have evolved resistance to the toxic effects of bufadienolides and prey regularly on toads. Resistance in snakes to the acute effects of these toxins is conferred by at least two amino acid substitutions in the cardiotonic steroid binding pocket of the Na + /K + -ATPase. We surveyed 100 species of snakes from a broad phylogenetic range for the presence or absence of resistance-conferring mutations. We found that such mutations occur in a much wider range of taxa than previously believed. Although all sequenced species known to consume toads exhibited the resistance mutations, many of the species possessing the mutations do not feed on toads, much less specialize on that food source. This suggests that either there is little performance cost associated with these mutations or they provide an unknown benefit. Furthermore, the distribution of the mutation among major clades of advanced snakes suggests that the origin of the mutation reflects evolutionary retention more than dietary constraint.

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Macrolide and fluoroquinolone associated mutations in Mycoplasma genitalium in a retrospective study of male and female patients seeking care at a STI Clinic in Guangzhou, China, 2016-2018

BMC Infectious Diseases ◽

10.1186/s12879-020-05659-3 ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Wujian Ke ◽

Dongling Li ◽

Lai Sze Tso ◽

Ran Wei ◽

Yinyuan Lan ◽

...

Keyword(s):

Amino Acid ◽

Antimicrobial Resistance ◽

Fluoroquinolone Resistance ◽

23S Rrna ◽

Resistance Testing ◽

Rrna Gene ◽

Amino Acid Substitutions ◽

Resistance Mutations ◽

Topoisomerase Iv ◽

Two Samples

Abstract Background Antimicrobial resistance in M. genitalium is a growing clinical problem. We investigated the mutations associated with macrolide and fluoroquinolone resistance, two commonly used medical regimens for treatment in China. Our aim is to analyze the prevalence and diversity of mutations among M. genitalium-positive clinical specimens in Guangzhou, south China. Methods A total of 154 stored M. genitalium positive specimens from men and women attending a STI clinic were tested for macrolide and fluoroquinolone mutations. M. genitalium was detected via TaqMan MGB real-time PCR. Mutations associated with macrolide resistance were detected using primers targeting region V of the 23S rRNA gene. Fluoroquinolone resistant mutations were screened via primers targeting topoisomerase IV (parC) and DNA gyrase (gyrA). Results 98.7% (152/154), 95.5% (147/154) and 90.3% (139/154) of M. genitalium positive samples produced sufficient amplicon for detecting resistance mutations in 23S rRNA, gyrA and parC genes, respectively. 66.4% (101/152), 0.7% (1/147) and 77.7% (108/139) samples manifested mutations in 23S rRNA, gyrA and parC genes, respectively. A2072G (59/101, 58.4%) and S83I (79/108, 73.1%) were highly predominating in 23S rRNA and parC genes, respectively. Two samples had amino acid substitutions in gyrA (M95I and A96T, respectively). Two samples had two amino acid substitutions in parC (S83I + D87Y). 48.6% (67/138) of samples harbored both macrolide and fluoroquinolone resistance-associated mutations. The most common combination of mutations was A2072G (23S rRNA) and S83I (parC) (40/67, 59.7%). One sample had three amino acid changes in 23S rRNA, gyrA and parC genes (A2072G + A96T + S83I). Conclusions The high antimicrobial resistance rate of M. genitalium in Guangzhou is a very worrying problem and suggests that antimicrobial resistance testing and the development of new antibiotic regimens are crucially needed.

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