Barrett, The Honors College Thesis/Creative Project Collection
Barrett, The Honors College at Arizona State University proudly showcases the work of undergraduate honors students by sharing this collection exclusively with the ASU community.
Barrett accepts high performing, academically engaged undergraduate students and works with them in collaboration with all of the other academic units at Arizona State University. All Barrett students complete a thesis or creative project which is an opportunity to explore an intellectual interest and produce an original piece of scholarly research. The thesis or creative project is supervised and defended in front of a faculty committee. Students are able to engage with professors who are nationally recognized in their fields and committed to working with honors students. Completing a Barrett thesis or creative project is an opportunity for undergraduate honors students to contribute to the ASU academic community in a meaningful way.
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- Creators: School of Life Sciences
Description
The diagnosis of bacterial infections based on phage multiplication has the potential for profound clinical implications, particularly for antibiotic-resistant strains and the slow-growing Mycobacterium tuberculosis. The possibility of hastening the diagnosis of antibiotic-resistant mycobacterial infections was accomplished via the study of Mycobacterium smegmatis, a generally non-pathogenic, comparatively fast growing microorganism to M. tuberculosis. These proof-of-concept studies established that after transduction of M. smegmatis cells with bacteriophages, MALDI-TOF MS could be used to detect increased amounts of phage proteins. Recording the growth of M. smegmatis over an 8-hour period, starting with very low OD600 measurements, simulated bacterial loads in clinical settings. For the purposes of MALDI-TOF MS, the procedure for the most effective lethal exposure for M. smegmatis was determined to be a 1-hour incubation in a 95°C water bath. Successful precipitation of the lytic mycobacteriophages D29 and Giles was performed using chloroform and methanol and overlaid with 1-2 μL of α-cyano-4-hydoxycinnaminic acid, which allowed for more distinct and repeatable MALDI-TOF MS spectra. Phage D29 was found to produce an m/z peak at 18.477 kDa, which may have indicated a 2+-charged ion of the 34.8 kDa minor tail protein. The Giles proteins that were identified with MALDI-TOF MS have not been directly compared to protein values reported in the scientific literature. However, the MALDI-TOF MS spectra suggested that distinct peaks existed between M. smegmatis mc2155 and mycobacteriophages, indicating that successful infection with lytic phage and replication thereafter may have occurred. The distinct peaks between M. smegmatis and the phage can be used as indicators of the presence of mycobacteria. At this point, the limits of detection of each phage must be elucidated in order for MALDI-TOF MS spectra to be successfully implemented as a mechanism to rapidly detect antibiotic-resistant mycobacteria.
ContributorsBarrett, Rachael Lauren (Author) / Haydel, Shelley (Thesis director) / Sandrin, Todd (Committee member) / Maarsingh, Jason (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Abstract The BIO 189 Life Sciences Career Paths course is a seminar course that is intended to acclimate incoming freshmen into the School of Life Sciences (SOLS). While there are instructors who organize and present in the class, upper division undergraduate students are primarily responsible for facilitating lectures and discussions and mentoring the freshmen. Prior research has demonstrated that the mentor-mentee relationship is a very important predictor of success and retention within all university first-year programs. While past studies focused on the student mentor-mentee relationships, there is limited research that measures student satisfaction within freshmen seminar courses, especially in areas of science, technology, engineering, and mathematics (STEM). The purpose of this project is to survey students about their perception of the BIO 189 course. The effort of the project is on pre-health students, as they initiate their undergraduate careers and attempt to achieve acceptance into professional school four years later. Analysis of Likert scale surveys distributed to 561 freshmen revealed that students with an emphasis on "medicine" in their majors preferred a BIO 189 course geared to pre-health interests whereas students seeking an emphasis on research (ecology and cell biology/genetics) sought a BIO 189 course focused on internship and employment opportunities. Assessment of the mentor-mentee relationship revealed that students (n = 561) preferred one-on-one meetings with mentors outside of class (44%) compared to those who preferred interaction in class (30%). A sizable 61.68% of students (n = 548) were most concerned with attaining favorable GPAs, highlighting strong emphasis on academic performance. Overall, 61% of respondents (n = 561) expressed satisfaction with SOLS resources and involvement opportunities, which was hypothesized. These results give substantial insight into the efficacy of a first-year success seminar-mentoring program for college freshmen in STEM.
ContributorsMaalouf, Nicholas Elie (Author) / Haydel, Shelley (Thesis director) / Harrell, Carita (Committee member) / Capco, David (Committee member) / Department of Psychology (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
The need for new tuberculocidal drugs is crucial with drug resistance on the rise as the tuberculosis epidemic rages on. One new potential drug target is the PrrAB two component system (TCS) since it does not exist in humans and is essential to viability in Mycobacterium tuberculosis. This project examines Mycobacterium smegmatis, and this nonpathogenic and fast-growing organism possesses two full length PrrAB orthologs, in addition to an orphaned PrrB sensor histidine kinase. While it was determined that PrrAB1 and PrrAB2 are nonessential, the lone PrrB3 is not yet characterized for essentiality. To confirm individual dispensability of PrrAB1 and PrrAB2 and investigate the essentiality of PrrB3 and the full M. smegmatis PrrAB multiplex, we utilized CRISPRi dCas9 to repress the expression (knockdown) of prrAB1 (MSMEG_5662-5663), prrAB2 (MSMEG_0244-0246), and the lone prrB3 (MSMEG_2793) in M. smegmatis independently and simultaneously. Repression of prrAB1 resulted in the greatest growth defect, with a lag of 17 cellular division cycles compared to the control, a strain generated with an empty vector. However, the knockdown of prrAB1 was not lethal to M. smegmatis. The inhibition of all three prrAB orthologs simultaneously, also known as a multiplex knockdown, lagged the control by 13 cellular division cycles. At the 48-hour point, both the single ortholog repression of prrAB1 as well as the whole prrAB system knockdown had a growth defect of 13 replication cycles behind the control. However, the multiplex knockdown stabilized growth at 48 hours, revealing a possible compensatory mechanism in M. smegmatis. Conclusively, we show that the PrrAB TCS is globally inessential for viability in M. smegmatis.
ContributorsHeiligenstein, Piper (Author) / Haydel, Shelley (Thesis director) / Shrivastava, Abhishek (Committee member) / Haller, Yannik (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor) / School of Mathematical and Natural Sciences (Contributor)
Created2023-12
Description
Mycobacterium abscessus (Mabs) is a multidrug-resistant nontuberculous mycobacterium capable of causing persistent pulmonary infection. It most prominently threatens those with cystic fibrosis (CF), a progressive and genetic disorder characterized by an immunocompromised respiratory tract. Current treatments fail to eradicate Mabs, meaning novel alternatives are greatly needed. Antimicrobial peptides (AMPs) are short sequences of amino acids that display broad-spectrum antimicrobial activity and play an important role in innate immunity. To maximize their therapeutic potential, key AMP features can be rationally combined through an iterative engineering process to create synthetic, designed AMPs (dAMPs). In this investigation, two dAMPs, RP554 and RP557, reduced Mabs ATCC 19977 viability by 99.99% and were subjected to further testing. In antimicrobial susceptibility testing with Mabs ATCC 19977, RP554 and RP557 demonstrated bactericidal activity at concentrations 16-32 μM. Complete killing of Mabs ATCC 19977 by RP554 and RP557 occurred rapidly in <24 h. RP554 and RP557 also inhibited 20 Mabs clinical isolates obtained from CF patients. Furthermore, RP554 and RP557 retained anti-Mabs activity after pre-exposure to human serum, indicating potential stability in blood. Conversely, the tested dAMPs did not kill Mabs during in vitro experiments in an artificial sputum medium. Novel antimicrobials, such as the RP554 and RP557 dAMPs, offer therapeutic potential for otherwise resistant bacterial pathogens, including Mabs, that afflict both CF and non-CF patients.
ContributorsBrandt, McKenzie (Author) / Haydel, Shelley (Thesis director) / Bean, Heather (Committee member) / Dermody, Roslyn (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2022-05