Disease prevention depends heavily on mosquito control since there are no approved vaccines to mosquito-transmitted disease such as dengue and yellow fever. However, conventional mosquito control programs use chemical and synthetic pesticides which induce non-target effects against important insect species and result in development of resistance in mosquitoes. Alternative control method using bio-insecticide is needed. This project will characterize the structure and mechanism of a newly discovered mosquito larvicidal peptide produced by Xenorhabdus bacteria. The knowledge gained through this effort will lead to a development of environmentally safe and mosquito-specific bio-insecticide. The proposed research will be conducted in collaboration with Dr. Do-Young Kim, a noted expert on proteomics research, at Pohang Technopark- Pohang Center for Evaluation of Biomaterials in South Korea. The expertise and equipments provided by Dr. Kim in structural analysis and microscopy study will play a pivotal role in the proposed research.
Structural analysis of toxin peptide will be conducted using a linear ion trap-Orbitrap (LTQ-Orbitrap) mass spectrometer. Amino acid composition of toxin peptide will be analyzed through an amino acid column connected to high pressure liquid chromatography equipped with fluorescence detector (HPLC-FLD). The super-resolution light microscope, N-SIM/N-STORM, will be used to examine how mosquito larvicidal toxin peptide alters mosquito midgut morphology and disrupts midgut epithelial cells. The successful outcome in this study will lead to the introduction of a new bio-pesticide. Although mosquito-borne diseases have been declared of being eradicated in the United States, it still affects millions of lives throughout the world. By developing a cost-effective and environmentally-friendly pesticide, this project aims to make a discovery that will improve global population health. This NSF EAPSI award is funded in collaboration with the National Research Foundation of Korea.
Mosquitoes transmit life threatening diseases such as dengue fever, yellow fever, and malaria. Primary disease prevention relies on controlling mosquito populations. However, mosquito resistance to most synthetic and biological pesticides is a problem, and there is an urgent need for new insecticides with a novel mode of action. This project aims to characterize the structure of a newly discovered mosquito larvicidal peptide produced by Xenorhabdus bacteria and understand the mode of action. The proposed research was conducted in collaboration with Dr. Do-Young Kim, a noted expert on proteomics research, at Pohang Technopark- Pohang Center for Evaluation of Biomaterials and Dr. Yeon-Soo Han, an expert on mosquito histology research, at Chonnam National University in South Korea. Structural analysis using linear ion trap-Orbitrap (LTQ-Orbitrap) mass spectrometer revealed the partial structure of the mosquito larvicidal lipopeptide, which is a key step for solving the full structure using nuclear magnetic resonance in the future. The techniques learned in Korea including preparing histological sections of mosquito midgut tissues and using confocal microscope were utilized to identify the initial binding regions of the larvicidal lipopeptide in a mosquito midgut. The results obtained here further confirmed that this lipopeptide toxin may employ a novel mode of action in killing mosquito larvae. Non-target effects of the Xenorhabdus lipopeptide toxin were examined against human cell lines, and the results indicated no cytotoxicity against human immune cells, epidermal cells, and intestinal cells. The long term goal of this project is to develop a cost-effective and environmentally-friendly biopesticide, and the EAPSI 2014 project made promising progress to fulfill the goal. During the EAPSI 2014 program in South Korea, I was fortunate to be involved in several activities outisde of the laboratory. I participated in a career guidance session at a local high school, and was involved in aiding student laboratory training sessions held at Pohang Technopark. I was also invited to give a presentation on my thesis project and networked with researchers at the 1st International Science, Technology, Engineering, and Mathematics (STEM) Student Symposium at Keimyung University. I have been in close contact with colleagues and collaborators I met through EAPSI in Korea, and I look forward to future collaboration.
