All constitutional isomers of beta bis-CF3 substituted (tpfc)PF2 were geometrically optimized and... more All constitutional isomers of beta bis-CF3 substituted (tpfc)PF2 were geometrically optimized and studied electronically. The six synthetically accessed compounds were characterized (of the 18 possible) by NMR spectroscopy and other techniques.
The honey bee is an important model system for increasing understanding of molecular and neural m... more The honey bee is an important model system for increasing understanding of molecular and neural mechanisms underlying social behaviors relevant to the agricultural industry and basic science. The western honey bee, Apis mellifera, has served as a model species, and its genome sequence has been published. In contrast, the genome of the Asian honey bee, Apis cerana, has not yet been sequenced. A. cerana has been raised in Asian countries for thousands of years and has brought considerable economic benefits to the apicultural industry. A cerana has divergent biological traits compared to A. mellifera and it has played a key role in maintaining biodiversity in eastern and southern Asia. Here we report the first whole genome sequence of A. cerana. Using de novo assembly methods, we produced a 238 Mbp draft of the A. cerana genome and generated 10,651 genes. A.cerana-specific genes were analyzed to better understand the novel characteristics of this honey bee species. Seventy-two percent ...
The sequences of the complete mitochondrial genome of the honey bee Apis mellifera L. subspecies ... more The sequences of the complete mitochondrial genome of the honey bee Apis mellifera L. subspecies Apis mellifera caucasia Pollmann, 1889 (AP018404, 16 341 bp) and Apis mellifera carpathica Foti et al., 1965 (AP018403, 16 336 bp) are sequenced for the first time. Mitochondrial DNA (mtDNA) of both subspecies contains 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and one AT-rich regulatory region. The ratio of transitions to transversions (tr/tv) in complete mtDNA between A. m. caucasia and A. m. carpathica was 2.05, which reflects the formation of adaptations to changing environmental conditions. Genes with the highest GC content—COX1 (24%), COX2 (19.6%), CYTB (19.1%), COX3 (17.2%), and ND1 (17.2%)—can be highly polymorphic and can be used in phylogenetic and population studies of bees. The majority of mtDNA genes of both subspecies are located on the heavy strand (9 protein-coding genes and 14 tRNA genes), while other genes (4 protein-coding genes, 2 rRNA genes, and 8 tRNA g...
SUMMARY Spatial learning abilities were tested in restrained cockroaches by observing antennal pr... more SUMMARY Spatial learning abilities were tested in restrained cockroaches by observing antennal projection responses towards the positions of a learned visual cue perceived monocularly by one eye in the context of a second stimulus provided to the contralateral eye. Memory of the position of the conditioning stimulus relative to the contralateral reference stimulus was tested by altering the relative positions of the two stimuli. Memory of the conditioning stimulus is retained if the angle between the conditioning stimulus and the contralateral reference stimulus is maintained. The results suggest that during learning the insect recognizes spatial relationships between the conditioning stimulus and the contralateral reference stimulus. Possible mechanisms, such as retinotopic matching versus angular matching, are discussed.
SUMMARYUsing antennal movements as an indicator of learning and retention, an associative learnin... more SUMMARYUsing antennal movements as an indicator of learning and retention, an associative learning paradigm has been developed to investigate associative memory between visual and olfactory stimuli. Experiments were performed on the restrained cockroach Periplaneta americana, which normally moves its antennae towards a localized odor source. Such `antennal projection responses'(APRs) are exploited to demonstrate long-term memory, where an APR is elicited by a conditioned stimulus (CS; green light point source) paired with a spatially coincident odor [the unconditioned stimulus (US)]. Association of the CS with the US is established after five trials. Before training, a visual cue alone does not elicit an APR. This behavior is elicited by a visual cue only after pairing it with an odor stimulus. The acquired APR to the green light cue persists for up to 72 h, indicative of long-term memory. This paradigm is thus suitable for future studies of neural correlates of learning and mem...
The systematics and phylogeny of flatfish is investigated on the complete sequence of nucleotides... more The systematics and phylogeny of flatfish is investigated on the complete sequence of nucleotides at subunit 1 cytochrome c oxidase (Co-1) and cytochrome b (Cyt-b) genes. In total 17 species from our collection and some species from GenBank were analyzed. Four types of trees were built: Bayesian (BA), maximum likelihood (ML), maximum parsimony (MP), and neighbor joining (NJ). These trees showed similar topology. Two separate clusters on the trees support subfamily Hippoglossoidinae and Hippoglossinae subdivision and monophyletic status of these taxa. The subfamily Pleuronectinae also can be considered monophyletic, if the tribe Microstomini is excluded from it and genus Lepidopsetta is moved into the tribe Pleuronectini. Mitogenomes represented by 25 complete sequences from NCBI GenBank were analyzed. After alignment two sets of nucleotide sequences were formed and investigated independently. One set included 13 structural genes (14,886 bp), the second set comprised by the mtDNA wit...
Abstract Mosquito-borne infectious diseases cause mortality and global infectious disease burden ... more Abstract Mosquito-borne infectious diseases cause mortality and global infectious disease burden worldwide. There are several electronic mosquito repellents (EMRs) based on ultrasound have been developed and commercialized to reduce human-mosquito contacts. However, the efficacy of EMRs against mosquitoes is still unclear. In this study, we present experimental evidence that ultrasound of different frequency and sound pressure differentially affects the host-seeking behavior of Aedes aegypti females. Behavioral tests were accompanied by molecular experiments to check whether mosquitoes respond to ultrasound and are there any changes in specific mRNA expression. Experiments in bioassays revealed that the ultrasound of 100 kHz frequency and 90–110 dB pressure significantly disrupted CO₂-oriented olfactory behaviors and blocked indoor invasion. Furthermore, a long time (>24 h) exposure to 100 kHz frequency/90 dB pressure of ultrasound decreased attractive behaviors to human skin. At the molecular level, there was no change in expression of odorant receptor co-receptor (AaOrco) in ultrasound treated animals, while one of the CO2 receptor genes, AaGr3, and putative hearing-related gene, AAEL009258, were down-regulated and up-regulated, respectively. Our study indicates that high frequency (100 kHz) and pressure (90–110 dB) of the ultrasound has repellent effects to olfactory–driven behaviors of mosquitoes.
In mosquitoes, precise and efficient finding of a host animal is crucial for survival. One of the... more In mosquitoes, precise and efficient finding of a host animal is crucial for survival. One of the poorly understood aspects of mosquito blood-feeding behavior is how these insects target an optimal site in order to penetrate the skin and blood vessels without alerting the host animal. Here we provide new findings that a piercing structure of the mouthpart of the mosquitoes, the stylet, is an essential apparatus for the stage in blood feeding. Indeed, the stylet possesses a number of sensory hairs located at the tip of the stylet. These hairs house olfactory receptor neurons that express two conventional olfactory receptors of Aedes aegypti (AaOrs), AaOr8 and AaOr49, together with the odorant co-receptor (AaOrco). In vivo calcium imaging using transfected cell lines demonstrated that AaOr8 and AaOr49 were activated by volatile compounds present in blood. Inhibition of gene expression of these AaOrs delayed blood feeding behaviors of the mosquito. Taken together, we identified olfacto...
All constitutional isomers of beta bis-CF3 substituted (tpfc)PF2 were geometrically optimized and... more All constitutional isomers of beta bis-CF3 substituted (tpfc)PF2 were geometrically optimized and studied electronically. The six synthetically accessed compounds were characterized (of the 18 possible) by NMR spectroscopy and other techniques.
The honey bee is an important model system for increasing understanding of molecular and neural m... more The honey bee is an important model system for increasing understanding of molecular and neural mechanisms underlying social behaviors relevant to the agricultural industry and basic science. The western honey bee, Apis mellifera, has served as a model species, and its genome sequence has been published. In contrast, the genome of the Asian honey bee, Apis cerana, has not yet been sequenced. A. cerana has been raised in Asian countries for thousands of years and has brought considerable economic benefits to the apicultural industry. A cerana has divergent biological traits compared to A. mellifera and it has played a key role in maintaining biodiversity in eastern and southern Asia. Here we report the first whole genome sequence of A. cerana. Using de novo assembly methods, we produced a 238 Mbp draft of the A. cerana genome and generated 10,651 genes. A.cerana-specific genes were analyzed to better understand the novel characteristics of this honey bee species. Seventy-two percent ...
The sequences of the complete mitochondrial genome of the honey bee Apis mellifera L. subspecies ... more The sequences of the complete mitochondrial genome of the honey bee Apis mellifera L. subspecies Apis mellifera caucasia Pollmann, 1889 (AP018404, 16 341 bp) and Apis mellifera carpathica Foti et al., 1965 (AP018403, 16 336 bp) are sequenced for the first time. Mitochondrial DNA (mtDNA) of both subspecies contains 13 protein-coding genes, 22 tRNA genes, two rRNA genes, and one AT-rich regulatory region. The ratio of transitions to transversions (tr/tv) in complete mtDNA between A. m. caucasia and A. m. carpathica was 2.05, which reflects the formation of adaptations to changing environmental conditions. Genes with the highest GC content—COX1 (24%), COX2 (19.6%), CYTB (19.1%), COX3 (17.2%), and ND1 (17.2%)—can be highly polymorphic and can be used in phylogenetic and population studies of bees. The majority of mtDNA genes of both subspecies are located on the heavy strand (9 protein-coding genes and 14 tRNA genes), while other genes (4 protein-coding genes, 2 rRNA genes, and 8 tRNA g...
SUMMARY Spatial learning abilities were tested in restrained cockroaches by observing antennal pr... more SUMMARY Spatial learning abilities were tested in restrained cockroaches by observing antennal projection responses towards the positions of a learned visual cue perceived monocularly by one eye in the context of a second stimulus provided to the contralateral eye. Memory of the position of the conditioning stimulus relative to the contralateral reference stimulus was tested by altering the relative positions of the two stimuli. Memory of the conditioning stimulus is retained if the angle between the conditioning stimulus and the contralateral reference stimulus is maintained. The results suggest that during learning the insect recognizes spatial relationships between the conditioning stimulus and the contralateral reference stimulus. Possible mechanisms, such as retinotopic matching versus angular matching, are discussed.
SUMMARYUsing antennal movements as an indicator of learning and retention, an associative learnin... more SUMMARYUsing antennal movements as an indicator of learning and retention, an associative learning paradigm has been developed to investigate associative memory between visual and olfactory stimuli. Experiments were performed on the restrained cockroach Periplaneta americana, which normally moves its antennae towards a localized odor source. Such `antennal projection responses'(APRs) are exploited to demonstrate long-term memory, where an APR is elicited by a conditioned stimulus (CS; green light point source) paired with a spatially coincident odor [the unconditioned stimulus (US)]. Association of the CS with the US is established after five trials. Before training, a visual cue alone does not elicit an APR. This behavior is elicited by a visual cue only after pairing it with an odor stimulus. The acquired APR to the green light cue persists for up to 72 h, indicative of long-term memory. This paradigm is thus suitable for future studies of neural correlates of learning and mem...
The systematics and phylogeny of flatfish is investigated on the complete sequence of nucleotides... more The systematics and phylogeny of flatfish is investigated on the complete sequence of nucleotides at subunit 1 cytochrome c oxidase (Co-1) and cytochrome b (Cyt-b) genes. In total 17 species from our collection and some species from GenBank were analyzed. Four types of trees were built: Bayesian (BA), maximum likelihood (ML), maximum parsimony (MP), and neighbor joining (NJ). These trees showed similar topology. Two separate clusters on the trees support subfamily Hippoglossoidinae and Hippoglossinae subdivision and monophyletic status of these taxa. The subfamily Pleuronectinae also can be considered monophyletic, if the tribe Microstomini is excluded from it and genus Lepidopsetta is moved into the tribe Pleuronectini. Mitogenomes represented by 25 complete sequences from NCBI GenBank were analyzed. After alignment two sets of nucleotide sequences were formed and investigated independently. One set included 13 structural genes (14,886 bp), the second set comprised by the mtDNA wit...
Abstract Mosquito-borne infectious diseases cause mortality and global infectious disease burden ... more Abstract Mosquito-borne infectious diseases cause mortality and global infectious disease burden worldwide. There are several electronic mosquito repellents (EMRs) based on ultrasound have been developed and commercialized to reduce human-mosquito contacts. However, the efficacy of EMRs against mosquitoes is still unclear. In this study, we present experimental evidence that ultrasound of different frequency and sound pressure differentially affects the host-seeking behavior of Aedes aegypti females. Behavioral tests were accompanied by molecular experiments to check whether mosquitoes respond to ultrasound and are there any changes in specific mRNA expression. Experiments in bioassays revealed that the ultrasound of 100 kHz frequency and 90–110 dB pressure significantly disrupted CO₂-oriented olfactory behaviors and blocked indoor invasion. Furthermore, a long time (>24 h) exposure to 100 kHz frequency/90 dB pressure of ultrasound decreased attractive behaviors to human skin. At the molecular level, there was no change in expression of odorant receptor co-receptor (AaOrco) in ultrasound treated animals, while one of the CO2 receptor genes, AaGr3, and putative hearing-related gene, AAEL009258, were down-regulated and up-regulated, respectively. Our study indicates that high frequency (100 kHz) and pressure (90–110 dB) of the ultrasound has repellent effects to olfactory–driven behaviors of mosquitoes.
In mosquitoes, precise and efficient finding of a host animal is crucial for survival. One of the... more In mosquitoes, precise and efficient finding of a host animal is crucial for survival. One of the poorly understood aspects of mosquito blood-feeding behavior is how these insects target an optimal site in order to penetrate the skin and blood vessels without alerting the host animal. Here we provide new findings that a piercing structure of the mouthpart of the mosquitoes, the stylet, is an essential apparatus for the stage in blood feeding. Indeed, the stylet possesses a number of sensory hairs located at the tip of the stylet. These hairs house olfactory receptor neurons that express two conventional olfactory receptors of Aedes aegypti (AaOrs), AaOr8 and AaOr49, together with the odorant co-receptor (AaOrco). In vivo calcium imaging using transfected cell lines demonstrated that AaOr8 and AaOr49 were activated by volatile compounds present in blood. Inhibition of gene expression of these AaOrs delayed blood feeding behaviors of the mosquito. Taken together, we identified olfacto...
Uploads
Papers by Hyungwook KWON