Analyzing the Caenorhabditis elegans mutants confer hypersusceptibility to enterohemorrhagic E coli colonization

論文翻譯標題: 分析參與出血性大腸桿菌寄殖的線蟲突變株
  • 楊 昉蓉

學生論文: Master's Thesis


Enterohemorrhagic E coli (EHEC) the major serotype is O157:H7 is a gram-negative rod-shaped bacterium that causes illness through water and food Patients infected by EHEC may lead to hemorrhagic diarrhea and hemolytic uremic syndrome In our previous study we found that E coli O157:H7 strain EDL933 infected and killed C elegans animals Moreover EHEC colonizes and replicates in the intestinal lumen of C elegans Several published literatures have identified the key bacterial factors required for E coli O157:H7 colonization however the host factors involved in EHEC colonization remain understudied Here we applied the EMS-mediated forward genetic screen for identifying the host factors involved in EHEC colonization in C elegans We have isolated 32 EMS (Ethyl methanesulfonate)-induced mutants conferred the INC (enhanced intestinal colonization) phenotype The INC phenotype of these mutants was reconfirmed by a secondary screen fed with the GFP-labeled EHEC We then examined whether these mutants exhibit different host susceptibility to EHEC infection To our surprise four mutants with the INC phenotype exhibited a significant EHEC resistant phenotype compared to the wild-type N2 animals Given that the mutation alleles in these four mutants enhance the EHEC intestinal colonization yet confer resistance to EHEC infection this phenomenon is contradictory to our current knowledge about bacterial infection We therefore turned our attentions to identify the identities of these alleles by conventional two-point mapping and SNP (single-nucleotide polymorphism) mapping The preliminary results showed the mutation locus of one strain YQ087 is located on chromosome V and the other three strains YQ139 YQ032 and YQ106 are located on chromosome I ranging between genetic location -6 to +5 We believe through our study on the function of the host factors required for EHEC colonization and infection may gain insights on the novel aspects of immunity in EHEC infection
獎項日期2014 八月 21
監督員Chang-Shi Chen (Supervisor)