Overexpression of Mutant Galactose Permease (_N376F) Effective for Utilization of Glucose/Xylose or Glucose/ Galactose Mixture by Engineered .

Mutant sugar transporter -N376F was overexpressed in for efficient utilization of xylose, which is one of the main components of cellulosic biomass. ScGal2_N376F, the -N376F-overexpressing strain, exhibited 47.04 g/l of xylose consumption and 26.

Monitoring of Pyrethroid Resistance Allele Frequency in the Common Bed Bug (Cimex lectularius) in the Republic of Korea.

Two-point mutations (V419L and L925I) on the voltage-sensitive sodium channel of bed bugs (Cimex lectularius) are known to confer pyrethroid resistance. To determine the status of pyrethroid resistance in bed bugs in Korea, resistance allele frequencies of bed bug strains collected from several US military installations in Korea and Mokpo, Jeollanamdo, from 2009-2019 were monitored using a quantitative sequencing. Most bed bugs were determined to have both of the point mutations except a few specimens, collected in 2009, 2012 and 2014, having only a single point mutation (L925I).

Alleviation of catabolite repression in : the thermotolerant SBK1 mutant simultaneously coferments glucose and xylose.

Background: Simultaneous cofermentation of glucose and xylose mixtures would be a cost-effective solution for the conversion of cellulosic biomass to high-value products. However, most yeasts ferment glucose and xylose sequentially due to glucose catabolite repression. A well known thermotolerant yeast, , was selected for this work because it possesses cost-effective advantages over for biofuel production from cellulosic biomass.

An investigation of the molecular and biochemical basis underlying chlorantraniliprole-resistant Drosophila strains and their cross-resistance to other insecticides.

Chlorantraniliprole is an anthranilic diamide insecticide that binds to the insect ryanodine receptor (RyR) and induces an uncontrolled release of Ca , resulting in paralysis and ultimately death of the target insects. Recently, it was reported that chlorantraniliprole-resistant diamondback moths, Plutella xylostella Linnaeus, have mutations in their RyR. In this study, we developed two different chlorantraniliprole-resistant Drosophila melanogaster strain.

Ethanol production from xylose is highly increased by the Kluyveromyces marxianus mutant 17694-DH1.

Directed evolutionary approach and random mutagenesis were performed on thermotolerant yeast Kluyveromyces marxianus KCTC17694 for isolating a yeast strain producing ethanol from xylose efficiently. The isolated mutant strain, K. marxianus 17694-DH1, showed 290% and 131% improvement in ethanol concentration and ethanol production yield from xylose, respectively, as compared with the parental strain.

Transcriptome-based identification and characterization of genes commonly responding to five different insecticides in the diamondback moth, Plutella xylostella.

When the 3rd instar larvae of the diamondback moth (DBM), Plutella xylostella, were pretreated with sublethal doses (LC) and then subsequently exposed to lethal doses (LC) of chlorantraniliprole, cypermethrin, dinotefuran, indoxacarb and spinosad via leaf dipping, their tolerance to insecticides was significantly enhanced. To identify genes that commonly respond to the treatment of different insecticides and are responsible for the tolerance enhancement, transcriptomic profiles of larvae treated with sublethal doses of the five insecticides were compared with that of untreated control. A total of 117,181 transcripts with a mean length of 662bp were generated by de novo assembly, of which 35,329 transcripts were annotated.

Agroinfiltration-based expression of hairpin RNA in soybean plants for RNA interference against Tetranychus urticae.

The coatomer subunit alpha (COPA) and aquaporin 9 (AQ9) genes from the two-spotted spider mite, Tetranychus urticae, were previously determined to exhibit RNA interference (RNAi)-based lethality when their double-stranded RNAs were systemically delivered via multi-unit chambers (Kwon et al., 2016 [8]). In current study, the hairpin RNAs of the COPA and AQ9 were transiently expressed in soybean plants by agroinfiltration.

Screening of target genes for RNAi in Tetranychus urticae and RNAi toxicity enhancement by chimeric genes.

Due to its rapid development of resistance to nearly all arrays of acaricide, Tetranychus urticae is extremely hard to control using conventional acaricides. As an alternative control measure of acaricide-resistant mites, RNA interference (RNAi)-based method has recently been suggested. A double-stranded RNA (dsRNA) delivery method using multi-unit chambers was established and employed to screen the RNAi toxicity of 42 T.

Phenotypic- and Genotypic-Resistance Detection for Adaptive Resistance Management in Tetranychus urticae Koch.

Rapid resistance detection is necessary for the adaptive management of acaricide-resistant populations of Tetranychus urticae. Detection of phenotypic and genotypic resistance was conducted by employing residual contact vial bioassay (RCV) and quantitative sequencing (QS) methods, respectively. RCV was useful for detecting the acaricide resistance levels of T.

Toxicodynamic mechanisms and monitoring of acaricide resistance in the two-spotted spider mite.

The two-spotted spider (Tetranychus urticae) is one of the most serious pests world-wide and has developed resistance to many types of acaricides. Various mutations on acaricide target site genes have been determined to be responsible for toxicodynamic resistance, and the genotyping and frequency prediction of these mutations can be employed as an alternative resistance monitoring strategy. A quantitative sequencing (QS) protocol was reported as a population-based genotyping technique, and applied for the determination of resistance allele frequencies in T.

Mutation and duplication of arthropod acetylcholinesterase: Implications for pesticide resistance and tolerance.

A series of common/shared point mutations in acetylcholinesterase (AChE) confers resistance to organophosphorus and carbamate insecticides in most arthropod pests. However, the mutations associated with reduced sensitivity to insecticides usually results in the reduction of catalytic efficiency and leads to a fitness disadvantage. To compensate for the reduced catalytic activity, overexpression of neuronal AChE appears to be necessary, which is achieved by a relatively recent duplication of the AChE gene (ace) as observed in the two-spotted spider mite and other insects.

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

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.

Estimation of the genome sizes of the chigger mites Leptotrombidium pallidum and Leptotrombidium scutellare based on quantitative PCR and k-mer analysis.

Background: Leptotrombidium pallidum and Leptotrombidium scutellare are the major vector mites for Orientia tsutsugamushi, the causative agent of scrub typhus. Before these organisms can be subjected to whole-genome sequencing, it is necessary to estimate their genome sizes to obtain basic information for establishing the strategies that should be used for genome sequencing and assembly.

Method: The genome sizes of L.

Biochemical and toxicological properties of two acetylcholinesterases from the common bed bug, Cimex lectularius.

We examined the molecular and enzymatic properties of two acetylcholinesterases (AChEs; ClAChE1 and ClAChE2) from the common bed bug, Cimex lectularius. Native polyacrylamide gel electrophoresis followed by activity staining and Western blotting revealed that ClAChE1 is the main catalytic enzyme and is abundantly expressed in various tissues. Both ClAChEs existed in dimeric form connected by a disulfide bridge and were attached to the membrane via a glycophosphatidylinositol anchor.

Knockdown resistance allele frequencies in North American head louse (Anoplura: Pediculidae) populations.

The study examines the extent and frequency of a knockdown-type resistance allele (kdr type) in North American populations of human head lice. Lice were collected from 32 locations in Canada and the United States. DNA was extracted from individual lice and used to determine their zygosity using the serial invasive signal amplification technique to detect the kdr-type T917I (TI) mutation, which is most responsible for nerve insensitivity that results in the kdr phenotype and permethrin resistance.

Induction of soluble AChE expression via alternative splicing by chemical stress in Drosophila melanogaster.

Various molecular forms of acetylcholinesterase (AChE) have been characterized in insects. Post-translational modification is known to be a major mechanism for the molecular diversity of insect AChE. However, multiple forms of Drosophila melanogaster AChE (DmAChE) were recently suggested to be generated via alternative splicing (Kim and Lee, 2013).

Screening of lethal genes for feeding RNAi by leaf disc-mediated systematic delivery of dsRNA in Tetranychus urticae.

To identify genes that kill Tetranychus urticae when knocked down via RNA interference (RNAi), several lethal genes were screened by the systemic delivery of dsRNA via leaf disc feeding. Four candidate genes (β subunit of coatomer protein complex, T-COPB2; M1 metalloprotease, T-M1MP; Ribosomal protein S4, T-RPS4; A subunit of V-ATPase, T-VATPase) and a control gene (EGFP) were tested for RNAi. All dsRNAs that permeated the leaf disc (ca.

The overexpression of acetylcholinesterase compensates for the reduced catalytic activity caused by resistance-conferring mutations in Tetranychus urticae.

The mutations (G228S, A391T and F439W) and duplication of the acetylcholinesterase (AChE) gene (Tuace) are involved in monocrotophos resistance in the two-spotted spider mites, Tetranychus urticae (Kwon et al., 2010a, b). The overexpression of T.

Comparison of the humoral and cellular immune responses between body and head lice following bacterial challenge.

The differences in the immune response between body lice, Pediculus humanus humanus, and head lice, Pediculus humanus capitis, were investigated initially by measuring the proliferation rates of two model bacteria, a Gram-positive Staphylococcus aureus and a Gram-negative Escherichia coli, following challenge by injection. Body lice showed a significantly reduced immune response compared to head lice particularly to E. coli at the early stage of the immune challenge.

Establishment of quantitative sequencing and filter contact vial bioassay for monitoring pyrethroid resistance in the common bed bug, Cimex lectularius.

Two point mutations (V419L and L925I) in the voltage-sensitive sodium channel alpha-subunit gene have been identified in deltamethrin-resistant bed bugs. A quantitative sequencing (QS) protocol was developed to establish a population-based genotyping method as a molecular resistance-monitoring tool based on the frequency of the two mutations. The nucleotide signal ratio at each mutation site was generated from sequencing chromatograms and plotted against the corresponding resistance allele frequency.

Biochemical and molecular analysis of deltamethrin resistance in the common bed bug (Hemiptera: Cimicidae).

This study establishes deltamethrin resistance in a common bed bug, Cimex lectularius L., population collected from New York City (NY-BB). The NY-BB population was 264-fold more resistant to 1% deltamethrin in contact bioassay compared with an insecticide-susceptible population collected in Florida (FL-BB).

Determination of permethrin resistance allele frequency of human head louse populations by quantitative sequencing.

A quantitative sequencing (QS) protocol that detects the frequencies of sodium channel mutations (M815I, T917I, and L920F) responsible for knockdown resistance in permethrin-resistant head lice (Pediculus humanus capitis De Geer) was tested as a population genotyping method for use as a preliminary resistance monitoring tool. Genomic DNA fragments of the sodium channel a-subunit gene that encompass the three mutation sites were polymerase chain reaction (PCR)-1 amplified from individual head lice with either resistant or susceptible genotypes, and combined in various ratios to generate standard DNA template mixtures for QS. After sequencing, the signal ratios between resistant and susceptible nucleotides were calculated and plotted against the corresponding resistance allele frequencies.