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The University of San Francisco

Master's Theses

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Full-Text Articles in Life Sciences

Biochemical Assay Optimization And Computational Screening Efforts To Identify Potential Luxs Inhibitors, Keeshia Q. Wang Dec 2013

Biochemical Assay Optimization And Computational Screening Efforts To Identify Potential Luxs Inhibitors, Keeshia Q. Wang

Master's Theses

Quorum sensing (QS) is a process of coordination of bacterial gene expression in response to cell population. System two QS is regulated by the small signaling molecule autoinducer-2 (AI-2) and is implicated in the infectious behaviors of various bacterial species. AI-2 is biosynthesized from S-ribosylhomocysteine (SRH) by the enzyme LuxS and induces interspecies cell-to-cell communication. Inhibition of LuxS would therefore inhibit interspecies QS. Herein, a search for novel molecular species that will competitively bind with SRH in the LuxS binding site is performed in silico. Computational screening results are then validated in vitro using an optimized LuxS inhibition …


Determining Parentage And The Effects Of Relatedness On Play Partner Preference In Belding's Ground Squirrels, Jessica Weidenbach Dec 2013

Determining Parentage And The Effects Of Relatedness On Play Partner Preference In Belding's Ground Squirrels, Jessica Weidenbach

Master's Theses

I investigated 1) multiple paternity in Belding’s ground squirrels (Urocitellus beldingi) and 2) social partner preferences in juvenile U. beldingi. Prior work with blood allozymes demonstrated multiple paternity in U. beldingi litters. I evaluated paternity using microsatellite DNA analysis, which is more accurate than examining blood allozymes. My results indicate that multiple paternity in U. beldingi is more extensive than previously shown, occurring in about 90% of litters with more than one juvenile, and averaging 2.95 fathers in multiply sired litters. I also evaluated the hypothesis that play and other social behavior promotes bonding among juvenile female …


Hcmv Promotes Breast Cancer Metastasis: Impacts Of Cmvil-10 In The Tumor Microenvironment, Robin Bishop Aug 2013

Hcmv Promotes Breast Cancer Metastasis: Impacts Of Cmvil-10 In The Tumor Microenvironment, Robin Bishop

Master's Theses

Human cytomegalovirus (HCMV) is a highly species-specific, common human pathogen. While a large majority of people are infected with HCMV worldwide, infection is typically asymptomatic in immune competent individuals. To enhance virus persistence and avoid immune detection by the host, HCMV exploits the strategy of encoding homologs of cellular cytokines. One factor produced by HCMV-infected cells is the viral cytokine cmvIL-10, which acts through the cellular IL-10 receptor to induce downstream cell signaling. In instances where HCMV-infected cells infiltrate the tumor microenvironment, the presence of cmvIL-10 in may initiate events that promote a more invasive tumor phenotype. Cancer cells that …


Effects Of Herbivory As An Ecological Constraint Of Willow Growth At A Restored Riparian Corridor, Jacqueline A. Mccrory May 2013

Effects Of Herbivory As An Ecological Constraint Of Willow Growth At A Restored Riparian Corridor, Jacqueline A. Mccrory

Master's Theses

A critical component of nearly all riparian restoration projects is the rapid successful recovery of native vegetation. The dynamic conditions and diverse biotic community supported by riparian ecosystems can present numerous constraints to restoration efforts. This study investigated stunted growth of arroyo willow (Salix lasiolepis) cuttings planted along the banks of Redwood Creek as part of the National Park Service’s Muir Beach Restoration Project to restore habitat for special status species in California. Based on observations of deer browsing, as well as signs of extensive biomass removal, I designed a field experiment using exclusionary fencing to test the significance of …


Biochemical Evaluation Of Srh Analogs As Potential Luxs Inhibitors, Richa Gupta Aug 2012

Biochemical Evaluation Of Srh Analogs As Potential Luxs Inhibitors, Richa Gupta

Master's Theses

Quorum sensing in bacteria is a process of cell-to-cell communication facilitated by small molecules called autoinducers. Interspecies quorum sensing is facilitated by the autoinducer AI-2. The enzyme LuxS catalyzes the formation of AI-2 from S-ribosyl homocysteine (SRH) in a wide variety of bacterial species. Inhibition of LuxS would therefore inhibit interspecies quorum sensing. The goal of this project is to establish biochemical assays for the evaluation of small molecules as potential LuxS inhibitors. The first assay is a conventional colorimetric assay that utilizes Ellman’s reagent to quantify the homocysteine byproduct of DPD production by LuxS. For this assay purified …


Synthesis Of S-Ribosyl-L-Homocysteine And Analogs Modified At The Homocysteine-C3 Position, Ruoyi Liu May 2012

Synthesis Of S-Ribosyl-L-Homocysteine And Analogs Modified At The Homocysteine-C3 Position, Ruoyi Liu

Master's Theses

Quorum sensing (QS) is a process of bacterial cell-to-cell communication that conveys population density information in order to coordinate gene expression to produce synchronized behaviors. QS regulates the expression of virulence genes in many species of bacteria; hence, the manipulation of QS pathways may lead to treatment options against many bacterial diseases. The LuxS enzyme converts S-ribosyl-L-homocysteine (SRH) into homocysteine (HCys) and 4(S),5-dihydroxypentane-2,3-dione (DPD), which is the precursor of autoinducer-2 (AI-2). Thus, inhibitors of LuxS could prevent QS by halting the conversion of SRH to AI-2 rendering the cell “uncommunicative”. This work shows the successful chemical synthesis …


Fine-Scale Genetic Structure And Parentage In Urocitellus Beldingi, Marissa R. Lafler Dec 2011

Fine-Scale Genetic Structure And Parentage In Urocitellus Beldingi, Marissa R. Lafler

Master's Theses

Urocitellus beldingi (Belding's ground squirrel), previously known as Spermophilus beldingi, is a social, montane rodent that occupies alpine and subalpine meadows in the Sierra Nevadas (Helgen et al. 2009). The Tioga Pass meadow (Mono Co. CA) population has been studied behaviorally and demographically for several decades. Microsatellites were developed for this species and conditions for polymerase chain reaction (PCR) were defined. Nine microsatellite loci amplified adequately and were in Hardy-Weinberg equilibrium, displaying an average heterozygosity of 0.67±0.19. These nine microsatellite loci were analyzed via PCR to elucidate the fine scale genetic structure, offering insight into population health, stochastic events, and …


Effects Of Experience On Maternal Behavior In Belding’S Ground Squirrels (Spermophilus Beldingi): Older And Wiser?, Mikael Langner May 2009

Effects Of Experience On Maternal Behavior In Belding’S Ground Squirrels (Spermophilus Beldingi): Older And Wiser?, Mikael Langner

Master's Theses

Maternal behavior is an important behavior because it influences whether or not raising one’s offspring is successful. Maternal experience is positively correlated with successful maternal behavior. This association is evident when comparing first-time mothers with mothers who have prior experience raising young. Life experience not related to raising young can also positively influence maternal behavior. In this work, the hypothesis that is tested is whether or not maternal experience enhances the ability of a female to assess the threat level of a situation. The model species used to conduct the study is the Belding ground squirrel (Spermophilus beldingi), …