Research Progress in Area 1 方向 ( 一 ) 課題進展 81 Abstract Extracellular vesicles (EVs) are vesicles that are secreted into the extracellular environment by eukaryotic and prokaryotic cells. EVs released by bacteria in marine are proposed to function to transport relatively high local concentrations of compounds or act as reactive surfaces to facilitate the interactions between microorganisms and environment. Alterations in environmental factors such as elevated temperatures and acidification of ocean waters may cause subversive changes in marine ecosystems. In this proposal, Prof. Guo’s team aims to investigate whether environmental changes influence biogenesis and functions of EVs released by bacteria. Their study will provide novel and important insights into functional roles of bacterial EVs in marine ecosystems. Research Activities and Progress • Analyzed the protein profiling of EVs released by Prochlorococcus MED4 strain by label-free quantitative mass spectrometry; • Investigated the abundance of MED4 EVs secreted under a light-dark cycle; • Analyzed the protein profiling of MED4 EVs released under the light phase and dark phase by label-free quantitative mass spectrometry; • Developed methods to extract proteins from biofilm and analyzed the protein profiling of the EVs release by marine biofilm through labelfree quantitative mass spectrometry. Key Findings • We found MED4 EVs are enriched with specific proteins performing particular cellular functions; • We provided first evidence of diel EV production in cyanobacteria and the speed of EV secretion was faster than the speed of EV uptake during the night time (Figure 1A); • Mass spec analyses revealed proteins in EVs that were specifically secreted or absorbed in the night time (Figure 1B), suggesting the release and absorbance of EVs are influenced by diel cycle; • We identified and characterized proteins that specifically enriched in EVs released by marine biofilm. Research Output Publication 1 Trained personnel 3 Patent 1 Investigation of Functional Roles of Bacterial Extracellular Vesicles in Marine Ecosystems Prof. Yusong Guo The Hong Kong University of Science and Technology Fig 1. Analyses of MED4 EVs released under the light phase and dark phase.
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