Phosphine (PH3) resistance in the stored-products insect pests has been reported throughout the world in various insect species, including Rhyzopertha dominica, Tribolium castaneum, and Cryptolestes ferrugineus, leading farmers and fumigators to identify new fumigation tools to control PH3-resistant insect pests in storage facilities. Understanding PH3-resistance mechanisms in insects might contribute to providing clues for the development of new chemicals, including fumigants, to control various PH3-resistant insects. A proteomic study has shown 15 decreased proteins in the PH3-resistant R. dominica (CRD343 strain) in comparison to the PH3-susceptible R. dominica, and among those 15 proteins, dihydrolipoamide dehydrogenase (DLD), a protein involved in the Krebs cycle, was identified (Park et al., 2008). The DLD polymorphisms responsible for genetic resistance have disulfide active sites for PH3 binding and are highly sensitive to arsenic exposure after mutagenesis in insects (R. dominica and T. castaneum) and Caenorhabditis elegans (Schlipalius et al., 2012). Here, two PH3- resistant S. oryzae strains were used to understand the development of PH3 resistance in these insects. Acute toxicity test by PH3 on the two PH3-resistant strains was undertaken followed by ethyl formate inhibition study on cytochrome c oxidase activity. The Lineweaver-Burk plots after inhibition studies showed there were significantly difference in inhibition mode between the resistant strains and the control. The RT-qPCR analysis and the next-generation sequencing of the mitochondrial DNA revealed significant changes in metabolism and energy production. Taken together, the PH3 resistance in S. oryzae was definitely acquired by the overall transformation of biochemical reactions to overcome PH3 toxicity.
The purpose of this study is to present a method that can estimate the height of reaction facilities for large structural experiment through load flow as primary design procedure. The characteristic of the load transmission according to the type of experiment was analyzed to obtain tensile and compressive forces occurring on the reaction facilities. Strong walls that are affected by the bending moment is applied the post-tensioning method, and the strong floor under the control of the tension and compression is designed in accordance with the load flow. And the optimum cross-section of the reaction facilities was obtained by comparing the stresses of the tensile stress and crack the concrete. Through validating elastic analysis, the design results were satisfied a given design conditions.
A growing interest in ecotoxicological study is on the development of tools and technical resources to assess or determine the effects of a variety of stresses on ecosystems. As many chemicals are synthesized and used for the various purposes, it is inevitable circumstance for organisms to meet the stressors in the environment. Thus, it is important for us to understand the impacts of the stressors to organisms and is essential to equip with a fast detecting system to predict of their behaviors. The high throughput technology using proteomic and metabolomic techniques has been introduced to satisfy such requirements to study the potential adverse effects of some chemicals. Ecotoxicproteomics and Ecotoxicometabolomics are discussed in this talk in terms of their possible role in ecotoxicological studies.
Ricania sp. is a pest to many crops in Korea. This pest prefers fruit crops especially, blueberry and apple trees. We tested the possibility of Ricania sp. control using of methylcinnamate. In the laboratory bioassay, the mortality of methylcinnamate against Ricania sp. adult with 100 and 250 time diluted solution was 36.6% and 13.3% respectively. While repellent that the use of methylcinnamate resulted rate of 43.3% with 100 time diluted solution and 40.0% in 250 time diluted solution. Insecticidal and repellent effect in semifield bioassay were higher than those in laboratory bioassay. From this result, methylcinnamate might have synergic effect for Ricania sp. management. The result of this study showed a possibility of Ricania. sp. control using methylcinnamate.