Here, we have demonstrated the successful exfoliation of graphite into a layered material with scotch tape-like exfoliation. Sulfur acts as an exfoliating agent and exfoliates the loosely bounded graphite stacks. The shear force by ball milling provides the force required to overcome the van der Waals force between the layers. The MnO2 nanorods were synthesized using a KMnO4 precursor in a hydrothermal arrangement, and due to their intrinsic chemisorption capability, they were doped for polysulfide trapping. With an initial capacity of 1150 mAh/g achieved by the MnO2 nanorod-doped exfoliate-graphite/sulfur composite material, the material has displayed its application in lithium–sulfur batteries, but its use is not limited; it can be a low-cost eco-friendly solution to various energy storage systems with extensive structural qualities.

이산화염소는 살충효과를 지니며, 이는 이 물질이 발생시키는 활성산소에 기인된다. 살충효과를 주는 주요 원인으로 이산화염소의 세포독 성에 주목하고 있다. 본 연구는 이산화염소가 유발하는 세포독성이 활성산소에 기인한 아폽토시스 유발로 가설을 세우고 이를 검증하였다. 화랑 곡나방(Plodia interpunctella) 유충에 이산화염소를 주입한 결과 전체혈구수의 뚜렷한 감소를 보였고, 이후 처리 유충은 사망하였다. 아폽토시스 세포치사과정을 규명하기 위해 TUNEL (terminal deoxynucleotidyl transferase nick end translation) 분석법을 적용하였다. 곤충 세포주의 하나인 Sf9 세포에 서로 다른 이산화염소를 처리하고 TUNEL 분석법으로 관찰한 결과 처리 농도에 비례하여 아폽토시스 비율이 증가하였다. 다 음으로 서로 다른 농도의 이산화염소를 화랑곡나방 유충에 주입하고 혈구 세포를 TUNEL 분석법으로 관찰한 결과 이산화염소는 처리 농도에 비례하여 아폽토시스 유발을 나타냈다. 그러나 항산화제인 비타민 E를 이산화염소와 함께 처리하면 비타민 E의 농도에 비례하여 이산화염소의 아폽토시스 유발을 억제하고 이에 따라 살충률도 감소하였다. 이러한 결과는 이산화염소에 기인한 세포독성은 활성산소에 기인한 아폽토시스 유 발로 이뤄졌다는 것을 제시하고 있다.

곤충 생리현상의 가소성은 후생유전적 변화와 밀접하게 관련을 지을 수 있다. 이 가설을 증명하기 위해 광식성인 파밤나방(Spodoptera exigua)을 대상으로 상이한 먹이 조건에 따라 이 곤충의 발육과 DNA 메틸화에 영향을 주는 지 분석하였다. 동일한 코호트로 부터 얻은 갓 부화한 유충을 최종령에 이르기까지 세 가지 다른 먹이(대파, 배추, 인공사료)로 섭식 처리하였다. 이 결과 상이한 먹이 조건에 따라 유충발육속도, 용화 율 및 우화율에서 뚜렷한 차이를 보였다. 인공사료로 사육된 유충이 가장 빠른 유충발육속도와 높은 용화율 및 우화율을 나타냈다. 반면에 두 자 연 기주 가운데는 대파가 배추에 비해 파밤나방 발육에 양호하였다. 이러한 먹이에 따른 변이는 혈림프 단백질 및 혈당에서도 차이가 나타났다. 또한 발육과 연계되었을 것으로 추정되는 인슐린유사펩타이드(SeILP1) 유전자의 발현 정도도 먹이조건에 따라 상이했다. 단일항체를 이용하여 파밤나방 게놈 DNA의 시토신 메틸화를 분석한 결과 이 부위에 DNA 메틸화가 검출되었으며, 메틸화 정도는 먹이 조건에 따라 상이했다. 이 결 과들은 동일 집단의 파밤나방이 상이한 먹이 조건에 따라 발육차이를 나타내고 또한 시토신 메틸화에 변이를 보여 이 곤충의 생리적 가소성에 후 생유전적 인자가 작용하고 있는 것을 제시한다.

이산화염소(ClO2) 훈증제는 살충효과를 나타낸다. 그러나 일부 곤충은 이산화염소에 대해 회피행동을 보여, 이 훈증제에 대한 방제효율을 크게 떨어뜨리고 있다. 본 연구는 이를 해결하기 위해 이산화염소 처리에 열처리를 추가하여 곤충의 이산화염소에 대한 회피행동을 줄여 살충효과를 극대화하는 전략을 세웠다. 이산화염소 훈증 처리는 거짓쌀도둑거저리(Tribolium castaneum)에 대해 살충효과를 주었으며, 시험 곤충이 노출된 조건에서 12 시간 처리할 때 유충에 대해서 383.67 ppm (153.63 - 955.78 ppm: 95% 신뢰구간), 성충에 대해서 397.75 ppm (354.46 - 446.13 ppm: 95% 신뢰구간)의 반수치사농도를 나타냈다. 그러나 먹이인 밀가루를 충분히 제공한 상태에서 이산화염소를 처리하면, 처리 약제에 반응하여 시험 곤충이 먹이 속으로 들어가는 회피행동을 보이면서 방제효과는 크게 낮아졌다. Y 튜브를 이용한 이 곤충의 먹이 선호성 행동을 분석한 결과 거짓쌀도둑거저리 성충은 이산화염소가 처리된 먹이를 회피하는 행동을 보였다. 그러나 촉각을 제거한 경우 이러한 회피행동은 둔화되었다. 거짓쌀도둑거저리에 6 시간 동안 46℃ 열처리를 하면 살충효과는 10% 이하로 낮지만, 처리된 성충들이 먹이 밖으로 나와 있는 것을 관찰하였다. 반면 400 ppm의 이산화염소를 단독으로 6 시간 처리한 결과 회피행동에 따라 전혀 살충효과를 보이지 않았다. 그러나 46℃ 열처리와 400 ppm의 이산화염소를 병행하여 6 시간 처리한 결과 살충효과는 95%로 크게 증가하였다. 따라서 열처리는 거짓쌀도둑거저리의 이산화염소에 대한 회피행동을 억제하여 살충효과를 증가시켰다.

Histone H4 is a protein subunit of nucleosomes in eukaryotes and play crucial roles in DNA package and in regulation of gene expression by covalent modification. A viral histone H4 is encoded in a polydnavirus called Cotesia plutellae bracovirus (CpBV). The viral H4 (CpBV-H4) is highly homologous with other H4 proteins except 38 extended residues in N terminus. Its expression alters insect gene expression and suppresses immune and development. In this study, CpBV-H4 was expressed in a natural host, Plutella xylostella, and its suppressive activity on host gene expression was detected by suppressive subtractive hybridization (SSH) technique. SSH targets, of which expressions were down-regulated by CpBV-H4, were read by 454 pyrosequencing and annotated using the published P. xylostella whole genome. Resulting targets were assigned to most GO functional categories. Two chromatin remodeling factors were included in the SSH targets. Lysine demethylase (Px-KDM) of P. xylostella was highly expressed during entire larval period in all tested tissues. However, the suppression of Px-KDM expression by a specific RNA interference (RNAi) did not affect immune response, but significantly impaired the larval development. SWI/SNF of P. xylostella (Px-SWI/SNF) was expressed in all developmental stages. Its RNAi did not affect larval development, but led to significant alteration in adult metamorphosis. CpBV-H4 suppressed expressions of both Px-KDM and Px-SWI/SNF, but its truncated mutant lacking in the extended N-terminal tail did not. These results suggest that the developmental alteration in P. xylostella parasitized by C. plutellae can be caused by an epigenetic control of CpBV-H4 against chromatin remodeling factors.

An oxidative fumigant is potent to kill insect pests infesting stored grains. Its oxidative activity generates reactive oxygen species (ROS), which has been considered to be a main insecticidal factor. Furthermore, the oxidative fumigant has cytotoxic effect to insect cell lines, but the cytotoxicity is abrogated by antioxidant treatment. This study aimed to extend the usefulness of the oxidative fumigant in terms of medical purpose against cancer cells. Five cancer cell lines HCT 116 (human colorectal), Lovo (human colorectal), SW480 (human colorectal), MDA-MB-231 (human breast), and MCF-7 (human breast) were tested to determine their susceptibility to the oxidative fumigant with reference to two insect cell lines (Sf9 and Hi-Five). All cancer cell lines were highly susceptible to the oxidative fumigant, compared to the insect cell lines. Interestingly, basal ROS levels of the cancer cell lines were much higher than the insect cell lines. Furthermore, the oxidative fumigant significantly increased the ROS levels in the cancer cells. Treatment of vitamin E as an antioxidant mitigated the cytotoxicity of the oxidative fumigant. Thus, the high susceptibility of cancer cells to the oxidative fumigant may be induced by their high inducible ROS production. This study also investigated the antiviral activity of the oxidative fumigant against insect and plant viruses. The oxidative fumigant significantly inactivated a baculovirus (dsDNA virus) by inhibiting polyhedral production in Sf9 cells. It also inactivated tobacco mosaic virus (ssRNA virus) by suppressing phytopathogenicity. These results support a broad effect of the oxidative fumigant, which can be applied to agricultural and medical purposes.

Insect immunity is innate and consists of cellular and humoral immune responses. Cellular immune response usually requires hemocyte-spreading behavior, which is accompanied by cytoskeletal rearrangement. A glycolytic enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), catalyzes an oxidation reaction of glyceraldehyde-3-phosphate to 1,3-biphosphoglycerate in the cytosol. Another function of GAPDH in mammalian cell is to bind C-terminal α-tubulin to facilitate cytoskeletal arrangement. An immunoprecipitation (IP) of viral protein, CpBV-CrV1, against hemocyte protein lysate revealed that CpBV-CrV1 binds to GAPDH, identified by MALDI-TOF analysis. RNA interference (RNAi) of GAPDH significantly suppressed cellular immune response, but neither RNAi of hexokinase nor aldolase suppressed the cellular immune response. A common molecular motif of CpBV-CrV1 and a-tubulin at C-terminal region supported the IP analysis. To test the role of α-tubulin motif in CpBV-CrV1, point mutations of CpBV-CrV1 were applied and resulted in loss of the biological activity of CpBV-CrV1. Furthermore, an immunofluorescence assay indicates CpBV-CrV1 colocalized with a-tubulin in hemocytes collected from Plutella xylostella parasitized by Cotesia plutellae possessing C. plutellae bracovirus (CpBV). This result suggests that GAPDH plays a critical role in hemocyte-spreading behavior during immune challenge, and it is a molecular target of the pathogenic virus.

Cotesia plutellae, an endoparasitoids braconid wasp, possesses a polydnaviruses (PDVs) called Cotesia plutellae bracovirus (CpBV) that encodes viral histone H4 (= CpBV-H4). This viral histone H4 shares high sequence homology (82.5%) with host`s H4 of P.xylostella, except an extended N-terminal tail consisting of 38 amino acid residues with nine lysines. Its extended N-terminal tail has been postulated to play a crucial role in suppressing host immunity, growth and development-associated genes, presumably through an epigenetic control mechanism. A suppression subtractive hybridization (SSH) analysis was analyzed in transcriptome by short-read sequencing technology and provided several target and non-target genes of a viral histone H4. In this study, we analyzed the effect CpBV-H4 on the expression of two target genes: Lysine-specific demethylase (KDM) and Serine proteinase inhibitor (Serpins). Transient expression of CpBV-H4 into non parasitized P. xylostella was performed by microinjection of a recombinant expression vector, and showed the expression up to 70 h. Under this transient expression condition, we analyzed the effect of CpBV-H4 on the expression of target genes by RT-PCR at different time points. Interestingly, the CpBV-H4 significantly inhibited the expression of these target genes, while the truncated CpBV-H4 deleting the N-terminal tail did not show this inhibitory effect. This study also showed that the viral histone H4 suppresses expressions of lysine-specific demethylase and serine proteinase inhibitor (Serpin2) to inhibit host growth and development.

A novel oxidant fumigation (NOF) has been considered as alternative fumigant to replace methyl bromide that is a serious ozone depleter. Its high oxidative activity has been used as a bleaching or sanitary agent. Though some reports an insecticidal activity of NOF, its insecticidal action is yet to be understood. This study was conducted with an observation of an insecticidal activity of NOF against Plodia interpunctella, which is a stored grain insect pest. Cytotoxicity test was performed by using MTT assay, NOF gave a significant cytotoxicity on both Sf9 cells and HiFive insect cell lines. Sf9 cells were higher susceptible (IC50 = 43.2+ 3.5 ppm) to chloride dioxide than HiFive cells (IC50 = 174.6 + 5.9 ppm). To understand its cytotoxic effect on P. interpunctella, the larval hemocytes were incubated in vitro with different doses of NOF for 40 min at room temperature. In a dose-dependent manner, NOF gave a significant toxicity to the hemocytes. When NOF was injected to larvae of P. interpunctella, it significantly reduced total hemocyte counts compared to control. These results indicate that NOF has cytotoxic effect against hemocytes of P. interpunctella. This hemolytic activity of NOF can be regarded as a lethal factor to the stored grain insect pest.

Polydnavirus are well known to interfere with the host endocrine system, causing immune suppression and other physiological disorders. The Cotesia rubculla polydnavirus gene products, CrV1, are known to be a potent immunosuppressive agent. CrV1 protein express within 12 h after viral infection at oviposition during deposition of parasitoid eggs and are mainly secreted in to host hemocyte, where it functions like phagocytosis and cell spreading. This study identified its homolog in CpBV and analyzed its molecular characteristics motif called “coiled-coil. A point mutation of Alanine to Proline of CpBV-CrV1 could lose the coiled-coil motif from in silico assay. The coiled type CpBV-CrV1 could inhibit host cellular immunity, however, interestingly the mutant CpBV-CrV1 lacking in coiled-coil motif completely lost the immunosuppressive activity. This study suggests that the coiled-coil motif is functional to inhibit host cellular immune responses. RNA interference against CrV1 significantly loses the inhibitory activity and thus further supporting the immunosuppressive activity of CrV1. In this study we also have analyzed the localization of CrV1 by transient transfection in HiFive Cell lines by in situ hybridization.

A viral histone H4 (=CpBV-H4) is encoded in a polydnavirus, Cotesia plutellae bracovirus, and symbiotically associated with an endoparasitoid wasp, C. plutellae. It has an extended N-terminal tail consisting of 38 amino acid residues, compared to the host H4 and this extended N-terminal tail has been postulated to play a crucial role in an epigenetic control of gene expression. The (SSH) suppression subtractive hybridization analysis was analyzed in transcriptome by short-read sequencing technology. The SSH analysis provided several target and nontarget genes of a viral histone H4. In this study, we analyzed the effect CpBV-H4 on the expression of two target genes serpins and histone lysine N-methyl transferase. Transient expression of CpBV-H4 by microinjecting recombinant expression vector to non parasitized larvae of Plutella xylostella showed that it was expressed up to 70 h. Under this transient expression condition, we analyzed the effect of CpBV-H4 on the expression of target genes by RT-PCR at different time points. Interestingly, the CpBV-H4 significantly inhibited the expression of target genes after 44 h, while the truncated CpBV-H4 deleting the N-terminal tail did not show the inhibitory activity.