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You searched for +publisher:"Brown University" +contributor:("Sogin, Mitchell"). Showing records 1 – 2 of 2 total matches.

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1. Lasek-Nesselquist, Erica. Population biology and Comparative Genomics of Giardia duodenalis Assemblages.

Degree: PhD, Division of Biology and Medicine. Ecological and Evolutionary Biology, 2009, Brown University

Giardia duodenalis is a major cause of diarrheal disease worldwide and eludes effective characterization at the population level due to the fact that the majority of genotypes remain refractory to culture. Most of the biology of Giardia is poorly understood including how Giardia causes sickness as virulence factors and toxins remain unidentified. Additionally, the prevalence and distribution of G. duodenalis among mammalian and even vertebrate species, the transmission dynamics of G. duodenalis between host species and whether genetic interactions occur between individuals require further elucidation. Although considered an asexual organism, recent discoveries suggest periodic recombination events. The question of whether Giardia has sex ties in with species diversity and transmission dynamics. Seven genetically distinct lineages, or Assemblages A-G define Giardia duodenalis. Assemblages A and B infect virtually all vertebrates but are the only two Assemblages capable of infecting humans. Assemblages C-G appear to be host-specific. Only Assemblages A and B are considered zoonotic but the presence of zoonotic and non-zoonotic genotypes within the same animal host at the same time provides opportunity for genetic interactions. Thus, understanding the prevalence and distribution of Assemblages A and B in wildlife is essential to controlling the spread of this parasite. My thesis involves exploring various aspects of Giardia duodenalis population biology using different scales of molecular data. Chapters one and two examine the molecular diversity and zoonotic potential of Giardia duodenalis in marine vertebrates. I also explore geographic and host species distributions and attempt to identify the major factors responsible for the spread of this parasite within the marine environment. Chapters 3 and 4 focus on defining populations or Assemblage boundaries. They rely on sequencing 2-7 molecular markers from each individual to address the issue of genetic exchange within and between Giardia duodenalis assemblages. These results allow us to evaluate the potential for generating new zoonoses and to determine whether assemblages represent distinct species. The final chapter employs a comparative genomic approach to more thoroughly define intra and inter assemblage differences of Assemblages A and B and identify any potential genetic interactions that blur population boundaries. Advisors/Committee Members: Sogin, Mitchell (director), Rand, David (director), Mark Welch, David (reader), Huber, Julie (reader), Katz, Laura (reader).

Subjects/Keywords: genetic exchange

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APA (6th Edition):

Lasek-Nesselquist, E. (2009). Population biology and Comparative Genomics of Giardia duodenalis Assemblages. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:230/

Chicago Manual of Style (16th Edition):

Lasek-Nesselquist, Erica. “Population biology and Comparative Genomics of Giardia duodenalis Assemblages.” 2009. Doctoral Dissertation, Brown University. Accessed June 01, 2020. https://repository.library.brown.edu/studio/item/bdr:230/.

MLA Handbook (7th Edition):

Lasek-Nesselquist, Erica. “Population biology and Comparative Genomics of Giardia duodenalis Assemblages.” 2009. Web. 01 Jun 2020.

Vancouver:

Lasek-Nesselquist E. Population biology and Comparative Genomics of Giardia duodenalis Assemblages. [Internet] [Doctoral dissertation]. Brown University; 2009. [cited 2020 Jun 01]. Available from: https://repository.library.brown.edu/studio/item/bdr:230/.

Council of Science Editors:

Lasek-Nesselquist E. Population biology and Comparative Genomics of Giardia duodenalis Assemblages. [Doctoral Dissertation]. Brown University; 2009. Available from: https://repository.library.brown.edu/studio/item/bdr:230/

2. Hasegawa, Yuko. Visualization of Microbial Communities Using Fluorescence In Situ Hybridization and Spectral Imaging Technology.

Degree: PhD, Molecular Biology, Cell Biology, and Biochemistry, 2013, Brown University

Fluorescence in situ hybridization (FISH) is a molecular labeling technique that can be used to visualize and taxonomically identify microbial cells. In this study, spectral imaging technology was used (1) to expand the number of distinguishable FISH probe-labeled microbial populations in a single experiment and (2) to differentiate FISH probe-conferred signals from background and autofluorescence signals. Imaging assays were optimized to visualize bacterial cells in (1) an artificial community, consisting of ten laboratory-grown Proteobacteria species; (2) two types of artificial human gut bacterial communities in gnotobiotic mouse intestines; and (3) a local seawater sample. Gut bacterial cells in gnotobiotic mice were further analyzed to investigate spatial arrangements of bacterial taxa in intestinal cross-sections. Preservation of three-dimensional structures in luminal contents was demonstrated by using Technovit H8100 plastic resin. To characterize spatial patterns of gut bacteria, intestinal cross-sections were subjected to FISH, tile-scan image acquisition, spectral imaging analysis and a number of spatial analyses. Up to nine fluorescent reporters assigned to gut bacterial taxa were distinguished simultaneously in a FISH experiment on intestinal sections. On the same or serial sections of the embedded intestines, spatial distribution patterns of mucus were also analyzed. Across large intestinal cross-sections, bacterial concentration was directly correlated with mucus concentration; higher concentrations of mucus were more densely colonized with bacterial cells. Bacterial cells were also enriched on subsets of visible, large food particles. At scales of millimeters to 100 microns, different bacterial taxa were generally well-mixed. At scales of 1 to 20 microns, however, habitat patchiness became evident and was reflected in bacterial distribution. Abundance of Bacteroides taxa correlated with one another more tightly than non-Bacteroides taxa at scales of 15 to 20 microns. In addition, micron-scale clustering was observed among the bacterial taxa affiliated with the phylum Bacteroidetes. The clustering typically peaked at around the distance of 2 ┬Ám. In contrast, Collinsella aerofaciens in the Phylum Actinobacteria and Ruminococcus torques in the Phylum Firmicutes were more likely to be distributed randomly with respect to other bacterial populations. Advisors/Committee Members: Sogin, Mitchell (Director), Borisy, Gary (Director), Gerbi, Susan (Reader), Rand, David (Reader), Brodsky, Alexander (Reader), Huber, Julie (Reader).

Subjects/Keywords: Fluorescence In Situ Hybridization

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Hasegawa, Y. (2013). Visualization of Microbial Communities Using Fluorescence In Situ Hybridization and Spectral Imaging Technology. (Doctoral Dissertation). Brown University. Retrieved from https://repository.library.brown.edu/studio/item/bdr:320534/

Chicago Manual of Style (16th Edition):

Hasegawa, Yuko. “Visualization of Microbial Communities Using Fluorescence In Situ Hybridization and Spectral Imaging Technology.” 2013. Doctoral Dissertation, Brown University. Accessed June 01, 2020. https://repository.library.brown.edu/studio/item/bdr:320534/.

MLA Handbook (7th Edition):

Hasegawa, Yuko. “Visualization of Microbial Communities Using Fluorescence In Situ Hybridization and Spectral Imaging Technology.” 2013. Web. 01 Jun 2020.

Vancouver:

Hasegawa Y. Visualization of Microbial Communities Using Fluorescence In Situ Hybridization and Spectral Imaging Technology. [Internet] [Doctoral dissertation]. Brown University; 2013. [cited 2020 Jun 01]. Available from: https://repository.library.brown.edu/studio/item/bdr:320534/.

Council of Science Editors:

Hasegawa Y. Visualization of Microbial Communities Using Fluorescence In Situ Hybridization and Spectral Imaging Technology. [Doctoral Dissertation]. Brown University; 2013. Available from: https://repository.library.brown.edu/studio/item/bdr:320534/

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