Honors & Awards
The Joseph R. McMicking Fellowship in Biological Sciences, Stanford University
Education & Certifications
B.S., Peking University, Integrated Science (2019)
Liqun Luo, Doctoral (Program)
Live cell fluorescence imaging reveals dynamic production and loss of bacterial flagella.
Bacterial flagella are nanomachines that drive bacteria motility and taxis in response to environmental changes. Whether flagella are permanent cell structures and, if not, the circumstances and timing of their production and loss during the bacterial life cycle remain poorly understood. Here we used the single polar flagellum of Vibrio alginolyticus as our model and, implementing in vivo fluorescence imaging, revealed that the percentage of flagellated bacteria (PFB) in a population varies substantially across different growth phases. In the early-exponential phase, the PFB increases rapidly through widespread production of flagella. In the mid-exponential phase, the PFB peaks at around 76% and the partitioning of flagella between the daughter cells is 1:1 and strictly at the old poles. After entering the stationary phase, the PFB starts to decline, mainly because daughter cells stop making new flagella after cell division. Interestingly, we observed that bacteria can actively abandon flagella after prolonged stationary culturing, though cell division has long been suspended. Further experimental investigations confirmed that flagella were ejected in V. alginolyticus, starting from breakage in the rod. Our results highlight the dynamic production and loss of flagella during the bacterial life cycle.
View details for DOI 10.1111/mmi.14511
View details for PubMedID 32259388
Transgenic Eimeria mitis expressing chicken interleukin 2 stimulated higher cellular immune response in chickens compared with the wild-type parasites
FRONTIERS IN MICROBIOLOGY
2015; 6: 533
Chicken coccidiosis, caused by Eimeria sp., occurs in almost all poultry farms and causes huge economic losses in the poultry industry. Although this disease could be controlled by vaccination, the reduced feed conservation ratio limits the widespread application of anticoccidial vaccines in broilers because some intermediate and/or low immunogenic Eimeria sp. only elicit partial protection. It is of importance to enhance the immunogenicity of these Eimeria sp. by adjuvants for more effective prevention of coccidiosis. Cytokines have remarkable effects on the immunogenicity of antigens. Interleukin 2 (IL-2), for example, significantly stimulates the activation of CD8+ T cells and other immune cells. In this study, we constructed a transgenic Eimeria mitis line (EmiChIL-2) expressing chicken IL-2 (ChIL-2) to investigate the adjuvant effect of ChIL-2 to enhance the immunogenicity of E. mitis against its infection. Stable transfected EmiChIL-2 population was obtained by pyrimethamine selection and verified by PCR, genome walking, western blotting and indirect immunofluorescence assay. Cellular immune response, E. mitis-specific IFN-γ secretion lymphocytes in the peripheral blood mononuclear cells, stimulated by EmiChIL-2 was analyzed by enzyme-linked immunospot assay (ELISPOT). The results showed that EmiChIL-2 stimulated a higher cellular immune response compared with that of the wild-type parasite infection in chickens. Moreover, after the immunization with EmiChIL-2, elevated cellular immune response as well as reduced oocyst output were observed These results indicated that ChIL-2 expressed by Eimeria sp. functions as adjuvant and IL-2 expressing Eimeria parasites are valuable vaccine strains against coccidiosis.
View details for DOI 10.3389/fmicb.2015.00533
View details for Web of Science ID 000356312600001
View details for PubMedID 26082759
View details for PubMedCentralID PMC4451583