An extremely low frequency magnetic field increases unconditioned larval movement of the common cutworm, Spodoptera litura : A novel model for a magnetoreceptive neurobehavioral study

채권석 한국곤충학회 2008 Entomological Research Vol.38 No.4

One of the most interesting features of magnetic field (MF) responsiveness in animals is the signal transduction mechanism from sensing MF to behavior. To develop a model system for understanding the process, we performed a preliminary behavioral assay using an insect, the common cutworm, Spodoptera litura (Fabricius). In contrast to sham exposure, a continuous 60 Hz oscillating MF (0.2 mT) induced a significant increase in movement in third instar larvae: the MF-induced movement was longer in total duration and had an earlier onset than movement from sham exposure. Not surprisingly, the movement duration of the group test was notably higher than that of the individual test, suggesting that the individual test is more favorable for assessing the MF effect on movement. Considering the simplicity of the experimental operation and obvious non-conditioned responsiveness to the MF, this model might be suitable for studying magnetoreception and following the signal transduction mechanism between neurons and behavior.

Characterization and Partial Purification of Storage Protein-1 Receptor in the Fat Body of Hyphantria cunea

Chae, Kwon Seok,Yoe, Sung Moon,Kim, Hak Ryul 한국동물학회 1995 동물학회지 Vol.38 No.4

Galleria mellonella 6-Tox Gene, Putative Immune Related Molecule in Lepidoptera

이준하,박승미,채권석,이인희 한국잠사학회 2010 International Journal of Industrial Entomology Vol.21 No.1

We have characterized full-length cDNA encoding Gall-6-tox protein, which was cloned from the fat body of the immunized Galleria mellonella larvae. The cloned cDNA of Gall-6-tox consists of 1301 nucleotides and contained an open reading frame of 891 nucleotides corresponding to a protein of 296 residues that includes a putative 16-residue signal sequence and a 280-residue mature peptide with a calculated mass of 30,707.73 Da. The deduced mature peptide contains conserved tandem repeats of six cysteine-stabilized alpha beta (Cs ) motifs, which was detected in scorpion toxins and insect defensins. In the sequence homology search, mature Gall-6-tox showed 34% and 28% amino acid sequence homology with Bomb-6-tox from Bombyx mori and Spod-11-tox from Spodoptera frugiperda, respectively. Gall-6-tox orthologs were only found in Lepidopteran species, indicating that this new immune-related gene family is specific to this insect order. RT-PCR analysis revealed that Gall-6-tox was expressed primarily in the larval fat bodies, hemocytes,and midgut against invading bacteria into hemocoel. Moreover, the expression time course of Gall-6-tox was examined up to 24 h in the fat bodies and midgut after injection of E. coli. Altogether, these results suggest that Gall-6-tox is derived from defensins and Gall-6-tox may play a critical role in Lepidoptera immune system.

담배거세미 나방(Spodoptera litura)의 유충으로부터 유도합성된 항균활성 단백질 Spodopsin IA, IB, IC의 정제 및 특성

최충식,여성문,채권석,김학렬 한국통합생물학회 1995 한국동물학회 뉴스레터 Vol.12 No.2

FXRα Down-Regulates LXRα Signaling at the CETP Promoter via a Common Element

박성수,최호중,김승진,김옥진,채권석,김응석 한국분자세포생물학회 2008 Molecules and cells Vol.26 No.4

The cholesteryl ester transfer protein (CETP), a key player in cholesterol metabolism, has been shown to promote the transfer of triglycerides from very low density lipoprotein (VLDL) and low density lipoprotein (LDL) to high density lipoprotein (HDL) in exchange for cholesterol ester. Here we demonstrate that farnesoid X receptor α (FXRα; NR1H4) down-regulates CETP expression in HepG2 cells. A FXRα ligand, chenodeoxycholic acid (CDCA), suppressed basal mRNA levels of the CETP gene in HepG2 cells in a dose-dependent manner. Using gel shift and chromatin immunoprecipitation (ChIP) assays, we found that FXRα could bind to the liver X receptor α ( L XRα; NR1H3) binding site (LXRE; DR4RE) located within the CETP 5′ promoter region. FXRα suppressed LXRα-induced DR4RE-luciferase activity and this effect was mediated by a binding competition between FXRα and LXRα for DR4RE. Furthermore, the addition of CDCA together with a LXRα ligand, GW3965, to HepG2 cells was shown to substantially decrease mRNA levels of hepatic CETP gene, which is typically induced by GW3965. Together, our data demonstrate that FXRα down-regulates CETP gene expression via binding to the DR4RE sequence within the CETP 5′ promoter and this FXRα binding is essential for FXRα inhibition of LXRα-induced CETP expression.

Reproducibility and desensitization of the power frequency magnetic field effect on movement of the common cutworm Spodoptera litura

류정민,김남정,원란,이상대,채권석 한국곤충학회 2009 Entomological Research Vol.39 No.6

All creatures on Earth, including human beings, can be influenced by the power frequency electromagnetic field (EMF), even though the consequence and degree of the effect may vary due to regional context, species, etc. Most of the outstanding scientific achievements about the EMF effect on life have come from behavioral studies. In such studies, in contrast to the geomagnetic field or static magnetic field (MF), the oscillating MF has attracted far less attention so far. Following a previous report, to attain deep basic knowledge about the effect of an extremely low frequency (ELF) MF on animal behavior, we characterized the 60-Hz MF-responsive movement activity of common cutworm larvae using sophisticated experimental schemes. The MF-exposed third instar larvae showed significantly reduced locomotive activity compared to the matching sham-exposed larvae. Moreover, repeated MF exposure to the same larvae up to three times also showed similar behavioral responsiveness even though the extent of movement decrease was attenuated by the repetition time. These results suggest that sinusoidal power frequency MF could disrupt the normal locomotory activity of insect larvae, and the insects may show adaptive desensitization to the same MF.

Purification and Characterization of Antibacterial Peptides, Spodopsin Ia and Ib Induced in the Larval Haemolymph of the Common Cutworm, Spodoptera Iitura

최정식,여성문,김웅석,채권석,Choi, Chung-Sik,Yoe, Sung-Moon,Kim, Eung-Seok,Chae, Kwon-Seok,Kim, Hak R. The Korean Society for Integrative Biology 1997 Korean journal of biological sciences Vol.1 No.3

Antibacterial activity was induced in the haemolymph of the common cutworm, Spodoptera litura by the artificial injection of E, coli Ek132. Antibacterial peptides were purified from the immunized haemolymph by heat treatment, ion-exchange chromatography, gel filtration chromatography, and reverse phase FPLC, and their physicochemical characteristics were investigated. These purified antibacterial peptides designated as spodopsin la and Ib were named after Spodoptera litura. Spodopsin la and Ib had the apparent molecular masses of 3, 823 Da and 3, 886 Da, respectively, and about 20% of the sequences had basic amino acids, such as lysine and arginine but no cysteine. Also, spodopsin l was confirmed to be a new member of cecropin family having a similar amino acid sequence to cecropin of lepidopteran insects, such as Bombyx mori and Hyalophora cecropia. The purified spodopsin was active against gram-positive as well as gram-negative bacteria.

세균의 활성산소종과 활성질소종에 대한 내성에서 NADH dehydrogenase-2 결손의 효과

박희정(Hee Jeong Park),채권석(Kwon Seok Chae),방일수(Iel Soo Bang) 대한구강악안면병리학회 2010 대한구강악안면병리학회지 Vol.34 No.6

The electron transport chain (ETC) delivers electrons from many substrates to reduce molecular oxygen to water. ETC accomplishes the stepwise transfer of electrons through series of protein complexes conferring oxidation-reduction reactions with concomitant transport of proton across membrane, generating a proton gradient which leads ATP synthesis by F0F1ATPase. Bacterial ETC initiates with oxidation of NADH by NADH dehydrogenase complex (complex Ⅰ). Therefore, damage of complex Ⅰ leads to insufficient function of ETC and accumulation of NADH inside the cell. Contribution of ETC activity and its consequent changes of NADH levels to bacterial damage response against reactive oxygen and nitrogen species (ROS/RNS) has been poorly understood. In this study, by constructing ndh mutant Salmonella lacking complex Ⅰ NADH dehydrogenase 2, we evaluated the effect of ETC deficiency to bacterial resistance against ROS and RNS. The growth of ndh mutant Salmonella is impaired in the culture media containing hydrogen peroxide, but rather accelerates in the media containing nitric oxide donors. Data suggest that redox potential of NADH accumulated inside the cell by ETC blockage may affect inversely to bacterial resistance against reactive oxygen species and reactive nitrogen species.

Effects of gravity on positive phototaxis in fruit fly Drosophila melanogaster

권순환,배지은,이상협,이상대,채권석 한국곤충학회 2016 Entomological Research Vol.46 No.4

Geotaxis and phototaxis are movements in response to gravity and light, respectively, and are commonly observed in nature. The interactions between these two types of movement have been shown to confer ecological advantages to many taxa. Although several studies have been conducted on phototaxis and geotaxis in various organisms, reports on the interactions between positive phototaxis and negative geotaxis are lacking. In the fruit fly, Drosophila melanogaster, any direct interactions that exist between positive phototaxis and negative geotaxis are yet to be determined and the ecological significance of such interactions remains unclear. In the present study, the effects of gravity on positive phototaxis in a Y‐maze were investigated using the Canton‐S wild type and gravity‐sensing‐deficient pyx3 mutant fruit flies. Gravity sensing was not necessary for horizontal positive phototaxis, but was required for vertical positive phototaxis. These results suggest that gravitoreception may selectively modulate positive phototaxis depending on the vertical and horizontal movements of the fruit flies.

Application of Dye-coated Ultrasmall Gadolinium Oxide Nanoparticles for Biomedical Dual Imaging

Xu Miao,Wenlong Xu,차현실,장용민,오인택,채권석,이강호 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.9

Nanoparticles are very important in biomedical imaging because their imaging properties are superior to those of small molecules. They can be further functionalized for multimodal imaging through surface modification. In this study, we synthesized dye-coated ultrasmall gadolinium oxide nanoparticles [dye = fluorescein and fluorescein isothiocyanate (FITC)] in one-pot and investigated their dual imaging properties. The dye-coated gadolinium oxide nanoparticles exhibited excellent relaxometric properties suitable for T1 magnetic resonance imaging (MRI): r1 = 9.8 s−1mM−1 (r2/r1 = 2.6) for fluorescein-coated nanoparticles (davg = 1.6 ± 0.1 nm) and r1 = 12.3 s−1mM−1 (r2/r1 = 2.3) for FITC-coated nanoparticles (davg = 1.4 ± 0.1 nm), and strong photoluminescence (PL) in the green region (around 514 nm) suitable for fluorescent imaging (FI). The dye-coated nanoparticles exhibited strong fluorescence in cellular confocal images and high contrast in T1 MR images in mice, suggesting that they are potential dual T1 MRI-FI agents.