Microbiological Sciences

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Research from the Department of Microbiological Sciences. The department website may be found at https://www.ndsu.edu/micro/

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Browsing Microbiological Sciences by browse.metadata.program "Veterinary and Microbiological Sciences"

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    16S Ribosomal RNA and Phylograms: Characterizing Student Reasoning to Learning Outcomes from the American Society for Microbiology Curriculum
    (North Dakota State University, 2017) Grassie, Chelsey Lee
    The American Society for Microbiology (ASM) has established a suggested curriculum for introductory microbiology courses that includes a focus on evolution. However, no data is published to describe how proficiently students address the learning outcomes, in part because validated assessments do not exist. Thus, the goal of this project was to develop assessment prompts that capture student understanding about fundamental statement five under the core concept of evolution. In total, 167 written responses were collected from upper-division microbiology courses, with pre-pharmacy and microbiology majors comprising the majority of students (74.6%). Two coders coded all written responses, and five student interviews were conducted. Results indicate that students have not retained instruction on 16S rRNA, or have not been exposed to it in their classes. Additionally, most students have not been exposed to phylograms, and are unfamiliar with genetic distance being represented on a phylogenetic tree. Emergent reasoning techniques are described.
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    lntraspecific Variation In Pathogenic Cryptosporidium parvum
    (North Dakota State University, 2010) Herges, Grant Richard
    Cryptosporidium causes cryptosporidiosis, an infectious diarrheal disease, which can become chronic and life-threatening in immunocompromised individuals. Cryptosporidium parvum and C. hominis are the primary causes of human cryptosporidiosis. Of these species, C. hominis only infects humans while C. parvum additionally infects ruminants, in particular neonatal calves. Therefore, understanding the transmission dynamics of C. parvum, particularly the specific contribution of zoonotic and anthroponotic transmission, is critical to the control of this pathogen. Cryptosporidium parvum genotypes have been identified which appear to be restricted to a single host, which suggests that this may be a heterogeneous species, with varying infection and transmission dynamics. The first objective to this thesis was to determine the population structure of pathogenic C. parvum in the upper Midwest United States. A total of 216 isolates from cases of human cryptosporidiosis in Minnesota and Wisconsin and 64 isolates from diarrheic calves in Minnesota, Wisconsin, and North Dakota were genotyped at 8 polymorphic loci. A total of 213 isolates, 167 from humans and 46 from calves, had complete multilocus types (MLT). There were 93 different Ml Ts and sixty of those Ml Ts were only represented by one isolate. Population analysis revealed a highly recombining, panmictic population that does not have any genetic, geographic, or host sub-structuring. The second objective to this thesis was to determine the variability in the in vitro infectivity of different C. parvum strains, IOWA II and Moredun. A quantitative RT-PCR approach was used to quantify expression of target genes during infection of HCT-8 cells. Fluorescence microscopy was used to quantify life cycle stages during infection. Our data showed that the IOWA II reached its sexual stages earlier and had a greater number of trophozoites/meronts at 24 h p.i. than Moredun. The host used for propagation of C. parvum also affected subsequent infectivity of HCT-8 cells.