Location
Presentation- College of Science and Mathematics
Document Type and Release Option
Thesis Presentation (Restricted to Georgia Southern)
Faculty Mentor
Dr. Marina Eremeeva
Faculty Mentor Email
meremeeva@georgiasouthern.edu
Presentation Year
2021
Start Date
26-4-2021 12:00 AM
End Date
30-4-2021 12:00 AM
Keywords
Georgia Southern University, Honors Symposium, Presentation
Description
Rickettsia are obligate intracellular tick-borne bacteria which cause acute undifferentiated febrile illness accompanied by headache, malaise, myalgia, and disseminated endothelial infection. Immune responses to Rickettsia and pathogenesis of rickettsioses are not fully understood. Current work with Rickettsia is limited to vertebrate models that are strictly regulated and have low throughput. Since innate immune system of vertebrates retains striking similarities with the immune response in insects, invertebrates are being used to study host responses to various pathogens. The purpose of this study was to evaluate if larvae of the greater wax moth Galleria mellonella (GML) can be used as an in vivo invertebrate model to study Rickettsia infection. GML were infected with 104 to 107 plaque-forming units (PFU) of Rickettsia philipii 364D, or R. rickettsii Sheila Smith and kept at 34°C for 120 hours. Controls were injected with heat-inactivated Rickettsia, K36 buffer, or not injected. Infected and control GML were examined daily for phenotypic and behavioral changes. Hemolymph was collected daily from 5 GML per group for microscopy and DNA extraction. SYBR-Green-PCR assay was used to estimate Rickettsia DNA copy numbers in the hemolymph of infected GML. Rickettsia rickettsii caused a dose-dependent lethal infection in GML. Larvae infected with less-virulent R. philipii survived but exhibited dose-dependent morphological and phenotypical changes. Rickettsia were detected in the hemolymph and hemocytes of infected GML by PCR and microscopy, respectively, at each point of infection. In conclusion, GML are susceptible to Rickettsia and should be explored further as an alternative model of infection.
Academic Unit
College of Science and Mathematics
Use of Galleria mellonella Larvae to Study Rickettsia Infection
Presentation- College of Science and Mathematics
Rickettsia are obligate intracellular tick-borne bacteria which cause acute undifferentiated febrile illness accompanied by headache, malaise, myalgia, and disseminated endothelial infection. Immune responses to Rickettsia and pathogenesis of rickettsioses are not fully understood. Current work with Rickettsia is limited to vertebrate models that are strictly regulated and have low throughput. Since innate immune system of vertebrates retains striking similarities with the immune response in insects, invertebrates are being used to study host responses to various pathogens. The purpose of this study was to evaluate if larvae of the greater wax moth Galleria mellonella (GML) can be used as an in vivo invertebrate model to study Rickettsia infection. GML were infected with 104 to 107 plaque-forming units (PFU) of Rickettsia philipii 364D, or R. rickettsii Sheila Smith and kept at 34°C for 120 hours. Controls were injected with heat-inactivated Rickettsia, K36 buffer, or not injected. Infected and control GML were examined daily for phenotypic and behavioral changes. Hemolymph was collected daily from 5 GML per group for microscopy and DNA extraction. SYBR-Green-PCR assay was used to estimate Rickettsia DNA copy numbers in the hemolymph of infected GML. Rickettsia rickettsii caused a dose-dependent lethal infection in GML. Larvae infected with less-virulent R. philipii survived but exhibited dose-dependent morphological and phenotypical changes. Rickettsia were detected in the hemolymph and hemocytes of infected GML by PCR and microscopy, respectively, at each point of infection. In conclusion, GML are susceptible to Rickettsia and should be explored further as an alternative model of infection.
Comments
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