Phosphoprotein analysis of soybean root hairs in response to Bradyrhizobium japonicum inoculation

Title from PDF of title page (University of Missouri--Columbia, viewed on March 4, 2013).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisors: Dr. Gary Stacey, Dr. Henry T. Nguyen and Dr. Dong XuIncludes bibliographical references.Vita.Ph. D. University of Missouri--Columbia 2012."December 2012."The nitrogen fixing symbiosis in soybean (Glycine max) is initiated by colonization of root hairs by the symbiotic bacterium Bradyrhizobium japonicum. Specificity in this symbiosis is determined very early during the initial stages of host-symbiont recognition which involve specific receptor kinases and subsequent kinase cascades. We characterized the phosphoproteome of isolated root hair cells colonized by B. japonicum and quantify the phosphorylation changes using isobaric tag 8-plex ITRAQ coupled to LC-MS/MS analysis. 273 phosphopeptides corresponding to 240 phosphoproteins were found to be significantly regulated in response to B. japonicum inoculation. By using in silico proteolytic digestion, we showed that the palaeopolyploid soybean genome has less unique peptides making it a challenging organism for quantitative proteomic analysis. Trypsin was shown to be the best choice for digestion of soybean proteins to maximize the number of unique peptides. To screen for the protein kinases that can phosphorylate the 240 phosphoproteins above, a synthetic peptide cocktail derived from 273 phosphopeptides significantly regulated by B. japonicum inoculation was developed. This peptide cocktail was shown to work well in a solution-phase, label-free peptide kinase assay in conjunction with MS/MS analysis. Using a RNAi-mediated gene silencing approach, GmRIN4a and GmRIN4b, the two RPM1-interacting proteins whose phosphorylation status increased upon B. japonicum inoculation, were shown to play an important role in the rhizobium-legume symbiosis. Efforts are now underway to investigate the function of GmRIN4 in more detailed.Includes bibliographical reference

THE UNSTEADY FLOW AFTER DAM BREAKING

Joint Research on Environmental Science and Technology for the Eart

2D-model of contaminant water transmission processes and numerical simulation on a natural lake

Nowadays, the water pollution problems in the lakes are urgent matters. The simulation of contaminant water transmission process plays important role in reality to improve people's life qualities. In this paper the 2D-mathematical model simulating transmission processes of some contaminant substances in one lake of Hanoi is studied. The finite volume method is used in model. The actions between substances are considered and the simulation results are compared with the measurements