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Full-Text Articles in Life Sciences

Tetrameric Photosystem I: From Initial Discovery And Characterization In Chroococcidiopsis Sp. Ts-821 To Exploration Of Its Distribution And Understanding Of Its Significance In Cyanobacteria, Meng Li Dec 2016

Tetrameric Photosystem I: From Initial Discovery And Characterization In Chroococcidiopsis Sp. Ts-821 To Exploration Of Its Distribution And Understanding Of Its Significance In Cyanobacteria, Meng Li

Doctoral Dissertations

Photosystem I (PSI) forms trimeric complexes in most characterized cyanobacteria. We had reported the tetrameric form of PSI in the unicellular cyanobacterium, Chroococcidiopsis sp. TS-821 (TS-821). Using Cryo-EM, a 3D model of the PSI tetramer structure at 11.5 [Angstrom] resolution was obtained and a 2D map within the membrane plane of at 6.1 [Angstrom]. In contrast to the three-fold symmetry in trimeric PSI crystal structure from T. elongatus, two different inter-monomer interactions involving PsaLs are found in the PSI tetramer. Phylogenetic analysis based on PsaL protein sequences shows that TS-821 is closely related to heterocyst-forming cyanobacteria. Additionally, this tetrameric …


Discovery And Characterization Of A New Group Of Is10 Insertion Sequences, Rachel Marie Kinzelman Aug 2016

Discovery And Characterization Of A New Group Of Is10 Insertion Sequences, Rachel Marie Kinzelman

Theses and Dissertations

Insertion sequences (ISs) are small mobile genetic elements that can have significant impact on the genotype and phenotype of a host organism. Previous work in this laboratory revealed an insertion sequence that disrupted the luxA gene in Vibrio harveyi strain BCB451, knocking out light production. Phylogenetic analysis of this insertion sequence, dubbed IS451, reveals that it is in the IS10 family, but represents a novel variant that is only 79% identical to other known IS10 sequences. Twelve copies of IS451 were isolated from a genomic library and sequenced, and were found to be essentially identical, but located in dispersed chromosomal …


Investigating Physiological Collaborations Between A Lower Termite And Its Symbionts, Brittany F. Peterson Mar 2016

Investigating Physiological Collaborations Between A Lower Termite And Its Symbionts, Brittany F. Peterson

Open Access Dissertations

This project was completed in an effort to better understand the contributions of symbiotic microbes to the biology of Reticulitermes flavipes, the eastern subterranean termite. Lower-termites, like R. flavipes, house symbionts from all three domains of life within their hindgut paunch. This intimate association is reflected in nearly every aspect of termite biology. Here, I investigate these physiological collaborations as they relate to digestion and immunity. My efforts focused on 1) quantifying the role of bacteria in wood digestion within the termite gut, 2) evaluating the role of symbionts in protection against pathogens, and 3) identifying gene products that bacterial …