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- Title
- Characterization of Novel Borrelia burgdorferi Transcripts Expressed during Tick and Mammalian Infection.
- Creator
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Adams, Philip, Jewett, Mollie, Rohde, Kyle, Moore, Sean, Fernandez-Valle, Cristina, University of Central Florida
- Abstract / Description
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The purpose of this dissertation is to characterize the transcriptome of Borrelia (Borreliella) burgdorferi to discover novel transcripts, important for pathogenesis. As a spirochete and the etiological agent of Lyme disease, the foremost vector-borne bacterial infection in the world, B. burgdorferi fulfills a distinctive niche among bacterial pathogens. Persisting in the disparate environments of a tick vector and mammalian reservoirs, it is absolutely dependent on its hosts for transmission...
Show moreThe purpose of this dissertation is to characterize the transcriptome of Borrelia (Borreliella) burgdorferi to discover novel transcripts, important for pathogenesis. As a spirochete and the etiological agent of Lyme disease, the foremost vector-borne bacterial infection in the world, B. burgdorferi fulfills a distinctive niche among bacterial pathogens. Persisting in the disparate environments of a tick vector and mammalian reservoirs, it is absolutely dependent on its hosts for transmission and nutrient acquisition. B. burgdorferi harbors a complex fragmented genome which is largely linear, unlike that of most prokaryotes, lacks an array of classically described metabolic genes, and contains an unusually large percentage of unique genomic sequences specific to Borrelia (Borreliella) species. To date, few regulatory mechanisms have been identified which contribute to the ability of the spirochete to sense and respond to its environment. Efforts to use global transcript analysis to elucidate the molecular mechanisms of B. burgdorferi host adaptation have proven challenging due to the low numbers of the pathogen present during infection. Previously, our laboratory successfully developed an in vivo expression technology based approach for B. burgdorferi (BbIVET) to identify spirochete promoter sequences that are active during a murine infection. This screen identified 233 unique putative promoters which mapped to locations across the entire genome. These putative infection-active B. burgdorferi promoters were not only located at the 5' end of annotated open reading frames (ORFs), but also mapped to unannotated locations antisense, intergenic, and intragenic to ORFs. Given the limited characterization of the B. burgdorferi transcriptome, this dissertation applies an RNA sequencing approach (5'RNA-seq) to globally annotate the transcriptional start sites (TSSs) and 5' processed ends of the spirochete's RNA during in vitro cultivation. This resulted in the discovery of numerous novel internal, intergenic, and antisense transcripts. Synergistic analysis combining Northern blotting techniques, alignments of these transcripts to BbIVET proposed promoters, and interrogation of promoter activity via in vivo live imaging of mice, confirmed the expression of a variety of RNAs during laboratory culture and mammalian infection. Further, as a means to improve quantitation of the expression of these transcripts, a new methodology was developed and applied to measure B. burgdorferi promoter activity during tick-pathogen interactions, in a strand specific manner. Finally, because the Lyme disease spirochete harbors many unclassified and unique genomic sequences, the mammalian infection-expressed gene bb0562, identified through BbIVET and 5'RNA-seq, was selected for targeted deletion and evaluation throughout B. burgdorferi's infectious cycle. This demonstrated that gene bb0562 encodes a membrane associated protein, whose presence is critical for establishing murine infection through the bite of an infected tick. In sum, this work contributes significant insight into the transcriptome of B. burgdorferi, provides an innovative approach for the analysis of RNA transcripts at the tick-pathogen interface, and identifies a novel gene critical for Lyme disease pathogenesis.
Show less - Date Issued
- 2017
- Identifier
- CFE0006707, ucf:51915
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006707
- Title
- THE EFFECTS OF POWER DISTANCE, AND GENDER ON THE USE OF NONVERBAL IMMEDIACY BEHAVIORS IN SYMMETRICAL AND ASYMMETRICAL POWER CONDITIONS: A CROSS-CULTURAL STUDY.
- Creator
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Santilli, Vincent, Miller, Ann, University of Central Florida
- Abstract / Description
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Previous cross-cultural research in nonverbal immediacy indicates that nonverbal immediacy behavior varies across cultures, and some researchers have suggested that power distance might serve as a moderating variable, however no research has systematically set out to determine whether that is the case. This study assessed the perceived use of nonverbal immediacy under symmetric and asymmetric power conditions, as well as gender, in three cultures: Brazil, Kenya, and the United States....
Show morePrevious cross-cultural research in nonverbal immediacy indicates that nonverbal immediacy behavior varies across cultures, and some researchers have suggested that power distance might serve as a moderating variable, however no research has systematically set out to determine whether that is the case. This study assessed the perceived use of nonverbal immediacy under symmetric and asymmetric power conditions, as well as gender, in three cultures: Brazil, Kenya, and the United States. Quantitative data was collected from 527 participants who completed a nonverbal immediacy measure and an individual power distance measure under either a symmetric or an asymmetric power condition. Results related to power distance partially supported the idea that cultural power distance may act as a moderating variable with regard to the use of nonverbal immediacy behaviors. Related to gender, results revealed that: (a) female participants perceived more nonverbal immediacy behaviors than males, (b) under symmetric power conditions females were perceived to use more nonverbal immediacy than males, and (c) under asymmetric power conditions there was no statistically significant difference between use of nonverbal immediacy behaviors between females and males. Implications of results, limitations, and suggestions for future research are presented.
Show less - Date Issued
- 2010
- Identifier
- CFE0003043, ucf:48368
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003043
- Title
- The Effects of Facial Cues on Consumer Judgment and Decision-Making.
- Creator
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Liu, Fan, He, Xin, Wang, Ze, Mao, Huifang, Sivo, Stephen, University of Central Florida
- Abstract / Description
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This dissertation investigates the roles of facial cues in consumer behavior. Specifically, the research examines the effect of facial structural resemblance, facial expressions, and other perceptual cues(-)in both individual and group settings(-)on consumer judgment and decision-making. Essay 1 examines the influence of facial resemblance on consumers' product purchase likelihood. This effect is moderated by consumers' mental construal, such that the effect of increased facial resemblance on...
Show moreThis dissertation investigates the roles of facial cues in consumer behavior. Specifically, the research examines the effect of facial structural resemblance, facial expressions, and other perceptual cues(-)in both individual and group settings(-)on consumer judgment and decision-making. Essay 1 examines the influence of facial resemblance on consumers' product purchase likelihood. This effect is moderated by consumers' mental construal, such that the effect of increased facial resemblance on product purchase likelihood occurs among consumers with high-level construals but not among those with low-level construals. Results of three experimental studies show that increased facial resemblance among team members enhances the perceived entitativity of the group, which in turn leads to more favorable intention of purchasing the product offered by the group. Essay 2 investigates the differential effects of recipients' group entitativity on two types of donation (time vs. money). Through three studies, the research demonstrates that high (versus low) group entitativity among the recipients increases donation of time but decreases donation of money. Such differential effects on donation of time versus money are driven by consumers' emotional or cognitive well-being associated with time or money donations. In essay 3, the effect of smile intensity on customer behavior is shown to be moderated by power and salience of ulterior motive. When employees' ulterior motive is not salient to customers, low-power customers evaluate the employee with intensified smiles more favorably compared to high-power customers. In contrast, when ulterior motive is made salient, high-power rather than low-power customers react more positively to smile intensity. Results show that the interactive effects between smile, power, and ulterior motive are driven by customers' warmth and competence perceptions. Collectively, this dissertation focuses on consumers' face-based judgments of individuals and teams, and investigates how such facial cues might influence consumers' attitude, purchase intention, and prosocial behavior.
Show less - Date Issued
- 2015
- Identifier
- CFE0005828, ucf:50930
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005828
- Title
- An Analysis of Undergraduate Elementary School Pre-Service Teachers' Ability to Contextualize Fraction Expressions and Decontextualize Fraction Word Problems.
- Creator
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Tapp, Laura, Ortiz, Enrique, Andreasen, Janet, Dixon, Juli, Witta, Eleanor, University of Central Florida
- Abstract / Description
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The focus of this research was to expand on existing literature by providing information on elementary school pre-service teachers' ability to contextualize fraction expressions and decontextualize fraction word problems. The elementary school pre-service teachers who participated in this study were enrolled in a mathematics for elementary school teachers content course in a college of education at a large university during the Spring 2016 semester. In this mixed-method study, the...
Show moreThe focus of this research was to expand on existing literature by providing information on elementary school pre-service teachers' ability to contextualize fraction expressions and decontextualize fraction word problems. The elementary school pre-service teachers who participated in this study were enrolled in a mathematics for elementary school teachers content course in a college of education at a large university during the Spring 2016 semester. In this mixed-method study, the participants were given the Contextualization and Decontextualization of Fractions Instrument (CDFI) which assessed elementary school pre-service teachers' ability to solve fraction word problems and identify decontextualized fraction word problems into expressions and contextualized fraction expressions into word problems. The elementary school pre-service teachers were given the CDFI before and after they completed a unit on fractions. Of the 52 participants who completed both the pre- and post- CDFI, 11 were selected to participant in think aloud interviews in which they decontextualized fraction expressions from word problems and solved and contextualized fraction word problems from expressions. Quantitative results showed an overall statistically significant difference in the elementary school pre-service teachers' pre- and post- test scores. With the exception of two questions, all questions on the CDFI showed a statistically significant difference between the pre- and the post- test scores. No statistical significance was found in the responses to the question that required the elementary school pre-service teachers to identify the expression that matched the given fraction subtraction word problem. A large number of participants correctly identified the correct subtraction expression on the pre-test, and only slightly more of them were able to identify the correct subtraction expression on the post-test. No statistical significance was found in the responses to the question that required the elementary school pre-service teachers to explain their selection of a contextualized fraction multiplication expression. Though there was an increase in the elementary school pre-service teachers' ability to explain their selection of the contextualized fraction multiplication expression, it was not statistically significant. The qualitative analysis of the think aloud interview data showed that some of the elementary school pre-service teachers struggled with contextualizing fraction expressions. Most of the elementary school pre-service teachers did not struggle with solving the fraction word problems, but did struggle with decontextualizing fraction multiplication word problems.
Show less - Date Issued
- 2016
- Identifier
- CFE0006506, ucf:51405
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006506
- Title
- The mauC gene encodes a versatile signal sequence and redox protein that can be utilized in native and non-native protein expression and electron trnasfer systems.
- Creator
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Dow, Brian, Davidson, Victor, Self, William, Rohde, Kyle, Tatulian, Suren, University of Central Florida
- Abstract / Description
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The redox-active type 1 copper site of amicyanin is composed of a single copper ion that is coordinated by two histidines, a methionine, and a cysteine residue. This redox site has a potential of +265 mV at pH7.5. Over ten angstroms away from the copper site resides a tryptophan residue whose fluorescence is quenched by the copper. The effects of the tryptophan on the electron transfer (ET) properties were investigated by site-directed mutagenesis. Lessons learned about the hydrogen bonding...
Show moreThe redox-active type 1 copper site of amicyanin is composed of a single copper ion that is coordinated by two histidines, a methionine, and a cysteine residue. This redox site has a potential of +265 mV at pH7.5. Over ten angstroms away from the copper site resides a tryptophan residue whose fluorescence is quenched by the copper. The effects of the tryptophan on the electron transfer (ET) properties were investigated by site-directed mutagenesis. Lessons learned about the hydrogen bonding network of amicyanin from the aforementioned study were attempted to be used as a model to increase the stability of another beta barrel protein, the immunoglobulin light chain variable domain (VL). In addition, amicyanin was used as an alternative redox partner with MauG. MauG is a diheme protein from the mau gene cluster that catalyzes the biogenesis of the tryptophan tryptophylquinone cofactor of methylamine dehydrogenase (MADH). The amicyanin-MauG complex was used to study the free energy dependence and impact of reorganization energy in biological electron transfer reactions.The sole tryptophan of amicyanin was converted to a tyrosine via site-directed mutagenesis. This mutation had no effect on the electron transfer parameters with its redox partners, methylamine dehydrogenase and cytochrome c-551i. However, the pKa of the pH-dependence of the redox potential of the copper site was shifted +0.5 pH units. This was a result of an additional hydrogen bond between Met51 and the copper coordinating residue His95 in the reduced form of amicyanin. This additional hydrogen bond stabilizes the reduced form. Also, the stability of the copper site and the protein overall was significantly decreased, as seen by the temperature dependence of the visible spectrum of the copper site and the circular dichroism spectrum of the protein. This destabilization is attributed to the loss of an interior, cross-barrel hydrogen bond.The VL is structurally similar to amicyanin, but it does not contain any cross-barrel hydrogen bonds. The importance of the cross-barrel hydrogen bond in stabilizing amicyanin is evident. A homologous bond in VL was attempted to be engineered by using site-directed mutagenesis to insert neutral residues with protonatable groups into the core of the protein. Wild-type (WT) VL was purified from the periplasm and found to be properly folded as determined by circular dichroism and size exclusion chromatography. Mutants were expressed in E. coli using the amicyanin signal sequence for periplasmic expression. Folded mutant protein could not be purified from the periplasm.When amicyanin is used in complex with MauG, it retains the pH-dependence of the redox potential of its copper site due to the looseness of the interprotein interface. The free energy of the reaction was manipulated by variation in pH from pH 5.8 to 8.0. The ET parameters are reorganization energy of 2.34 eV and an electronic coupling constant of 0.6 cm-1. P94A amicyanin has a potential that is 120 mV higher than WT amicyanin and was used to extend the range of the free energy dependence studied. The ET parameters of the reaction of WT and P94A amicyanin with MauG were within error of each other. This is significant because the ET reaction of P94A amicyanin with its natural electron acceptor was not able to be studied due to a kinetic coupling of the ET step with a non-ET step. This kinetic coupling obscured the parameters of the ET step because it is not kinetically distinguishable from the ET step.A Y294H MauG mutant was also studied. This mutation replaced the axial tyrosine ligand of the six-coordinate heme of MauG with a histidine. No reaction is observed with Y294H MauG in its native reaction. However, the high valent oxidation state of the five-coordinate heme of Y294H MauG reacts with reduced amicyanin. The ET rate was analyzed by ET theory to study the high valent heme in Y294H MauG. The reorganization energy of Y294H MauG was calculated to be nearly 20% lower as compared to the same reaction with WT MauG. These results provide insight into the obscured nature of reorganization energy of large redox cofactors in proteins, particularly heme cofactors, as well as to how the active sites of enzymes are optimized to perform long range ET vs catalysis with regard to balancing redox potential and reorganization energy.
Show less - Date Issued
- 2016
- Identifier
- CFE0006100, ucf:51192
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006100
- Title
- TOWARD BUILDING A SOCIAL ROBOT WITH AN EMOTION-BASED INTERNAL CONTROL AND EXTERNAL COMMUNICATION TO ENHANCE HUMAN-ROBOT INTERACTION.
- Creator
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Marpaung, Andreas, Lisetti, Christine, University of Central Florida
- Abstract / Description
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In this thesis, we aim at modeling some aspects of the functional role of emotions on an autonomous embodied agent. We begin by describing our robotic prototype, Cherry--a robot with the task of being a tour guide and an office assistant for the Computer Science Department at the University of Central Florida. Cherry did not have a formal emotion representation of internal states, but did have the ability to express emotions through her multimodal interface. The thesis presents the results of...
Show moreIn this thesis, we aim at modeling some aspects of the functional role of emotions on an autonomous embodied agent. We begin by describing our robotic prototype, Cherry--a robot with the task of being a tour guide and an office assistant for the Computer Science Department at the University of Central Florida. Cherry did not have a formal emotion representation of internal states, but did have the ability to express emotions through her multimodal interface. The thesis presents the results of a survey we performed via our social informatics approach where we found that: (1) the idea of having emotions in a robot was warmly accepted by Cherry's users, and (2) the intended users were pleased with our initial interface design and functionalities. Guided by these results, we transferred our previous code to a human-height and more robust robot--Petra, the PeopleBot™--where we began to build a formal emotion mechanism and representation for internal states to correspond to the external expressions of Cherry's interface. We describe our overall three-layered architecture, and propose the design of the sensory motor level (the first layer of the three-layered architecture) inspired by the Multilevel Process Theory of Emotion on one hand, and hybrid robotic architecture on the other hand. The sensory-motor level receives and processes incoming stimuli with fuzzy logic and produces emotion-like states without any further willful planning or learning. We will discuss how Petra has been equipped with sonar and vision for obstacle avoidance as well as vision for face recognition, which are used when she roams around the hallway to engage in social interactions with humans. We hope that the sensory motor level in Petra could serve as a foundation for further works in modeling the three-layered architecture of the Emotion State Generator.
Show less - Date Issued
- 2004
- Identifier
- CFE0000286, ucf:46228
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000286
- Title
- A Comparative Evaluation of FDSA,GA, and SA Non-Linear Programming Algorithms and Development of System-Optimal Dynamic Congestion Pricing Methodology on I-95 Express.
- Creator
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Graham, Don, Radwan, Ahmed, Abdel-Aty, Mohamed, Al-Deek, Haitham, Uddin, Nizam, University of Central Florida
- Abstract / Description
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As urban population across the globe increases, the demand for adequatetransportation grows. Several strategies have been suggested as a solution to the congestion which results from this high demand outpacing the existing supply of transportation facilities.High (-)Occupancy Toll (HOT) lanes have become increasingly more popular as a feature on today's highway system. The I-95 Express HOT lane in Miami Florida, which is currently being expanded from a single Phase (Phase I) into two Phases,...
Show moreAs urban population across the globe increases, the demand for adequatetransportation grows. Several strategies have been suggested as a solution to the congestion which results from this high demand outpacing the existing supply of transportation facilities.High (-)Occupancy Toll (HOT) lanes have become increasingly more popular as a feature on today's highway system. The I-95 Express HOT lane in Miami Florida, which is currently being expanded from a single Phase (Phase I) into two Phases, is one such HOT facility. With the growing abundance of such facilities comes the need for in- depth study of demand patterns and development of an appropriate pricing scheme which reduces congestion.This research develops a method for dynamic pricing on the I-95 HOT facility such as to minimize total travel time and reduce congestion. We apply non-linear programming (NLP) techniques and the finite difference stochastic approximation (FDSA), genetic algorithm (GA) and simulated annealing (SA) stochastic algorithms to formulate and solve the problem within a cell transmission framework. The solution produced is the optimal flow and optimal toll required to minimize total travel time and thus is the system-optimal solution.We perform a comparative evaluation of FDSA, GA and SA non-linear programmingalgorithms used to solve the NLP and the ANOVA results show that there are differences in the performance of the NLP algorithms in solving this problem and reducing travel time. We then conclude by demonstrating that econometric forecasting methods utilizing vector autoregressive (VAR) techniques can be applied to successfully forecast demand for Phase 2 of the 95 Express which is planned for 2014.
Show less - Date Issued
- 2013
- Identifier
- CFE0005000, ucf:50019
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005000
