Open Research Oklahoma (Oklahoma State Univ.)
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Use of a heme biosensor to detect intracellular heme in Mycobacterium tuberculosis
No full textMycobacterium tuberculosis (Mtb), the causative agent of human tuberculosis (TB), is transmitted through aerosols and successfully replicates in the human lung. Before the SARS-CoV-2 pandemic, Mtb was the leading cause of death worldwide from a single infectious agent. In 2021, 11 million people were infected with Mtb resulting in 1.3 million deaths. The WHO estimates that globally 3.3% of new cases and 18% of previously treated cases were multidrug resistant TB in 2021. A general goal in our lab is to understand essential biological systems of Mtb so that we can develop new ways to block these essential systems and treat Mtb infections.Iron is an essential nutrient for all living organisms because iron is used for DNA replication, energy production and numerous other essential biological processes. Therefore, to successfully colonize the human host and cause disease Mtb is completely dependent on acquiring iron from within the human host. In the human body, >80% of the iron is stored in a molecule called heme and heme is then stored in the form of hemoglobin, which is a major component in our blood. This type of iron complexing is purposely done by the human immune system to prevent pathogens from acquiring the essential iron nutrient. Not surprisingly, most bacterial pathogens have developed elegant ways to acquire iron from heme, which is a rich source of iron. A specific goal in the Mitra Lab is to identify Mtb proteins that are used to capture host heme and to understand how these Mtb heme capturing proteins function.The Mitra Lab has identified several potential candidate genes that could be required for Mtb heme acquisition. An example of such a gene is eccC4. A previous experiment showed the growth of the parent strain and the eccC4 mutant strain. The two strains are grown in the presence of two different iron sources, ferric citrate (FeCi) and heme (Hm). FeCi is a non-heme iron source and serves as a control condition. When eccC4 is grown in heme, the growth is reduced compared to the parent strain grown in heme. The growth experiment showed that deleting the gene eccC4 reduces growth of Mtb only when heme is the iron source.My goal of the project was to assess a heme biosensor function and construct gene deletions. To construct gene deletions, we employed molecular biology techniques such as PCR, cloning, ligation, transformation, and homologous recombination. To assess effect of gene deletions, I performed several growth experiments. I measured both the optical density of the bacteria and the fluorescence. For example, based on previous observations we can reason that the slow growth of the eccC4 mutant in heme iron could be for two reasons: cells are not taking up enough heme into the cell and the cells are dying from a lack of iron nutrient or heme is accumulating within cells because not enough heme is being expelled out of the cell and they are dying from heme overload toxicity (because excess heme is poisonous to all organisms). To test these hypotheses, we used a molecular heme sensor which produces green fluorescing light (GFL) in response to heme. The level of GFL produced by the sensor is inversely proportional to the levels of heme. Thus, the level of GFL will be low in the presence of heme and high in the absence of heme. First, we produced this biosensor protein in both parent and mutant cells. Then, we grew the parent and mutant strains in medium with heme, measure cell density and GFL level in the strains. Based on our hypotheses, if the eccC4 mutant cells have lower levels of heme than the parent cells, then the GFL level will be higher in the eccC4 mutant compared to the parent strain and vice versa.Once we had performed the experiments, we analyzed the results by graphing the fluorescence levels of the ppe64 mutant and eccC4 mutant against our wild type in both ferric citrate and heme. Both mutant cells had more fluorescence within the heme, suggesting that heme levels were lower than in the mutant. From this, we can assume that the deletion of eccC4 and ppe64 reduces the heme uptake in Mtb. The conclusions of my research are that an intracellular heme biosensor can be used in Mtb to compare the cytoplasmic heme levels and that the PPE64 and ESX-4 secretion system are involved in the uptake of heme in Mtb. Future experiments should repeat the same tests to check for validity with more replicates and more timepoints in the growth curves and analyze other Mtb mutants
Shiga toxin 2 overexpression in Escherichia coli O157:H7 strains associated with severe human disease
No full textVariation in disease severity among Escherichia coli O157:H7 infections may result from differential expression of Shiga toxin 2 (Stx2). Eleven strains belonging to four prominent phylogenetic clades, including clade 8 strains representative of the 2006 U.S. spinach outbreak, were examined for stx2 expression by real-time PCR and western blot analysis. Clade 8 strains were shown to overexpress stx2 basally, and following induction with ciprofloxacin when compared to strains from clades 1-3. Differences in stx2 expression generally correlated with Stx2 protein levels. Single-nucleotide polymorphisms identified in regions upstream of stx2AB in clade 8 strains were largely absent in non-clade 8 strains. This study concludes that stx2 overexpression is common to strains from clade 8 associated with hemolytic uremic syndrome, and describes SNPs which may affect stx2 expression and which could be useful in the genetic differentiation of highly-virulent strains.Microbiology and Molecular Genetic
Design and validation of a versatile thermomechanical fatigue test system retrofit kit
No full textThis paper presents the design and experimental validation of a low-cost thermomechanical fatigue (TMF) test system that can be retrofitted to a dynamic
load universal test machine with minimal modifications. The motivation for this study
is to fabricate a cost-effective and universally compatible thermomechanical fatigue
testing system that has the ability to evaluate ferromagnetic aerospace materials.
Typically, TMF test systems are available from an original equipment manufacturer
(OEM) for a complete system or as a retrofit kit, costing as much as 300,000, respectively. Also, OEM equipment is not interchangeable with other systems
and requires manufacturer specific components to operate. An analytical study
was performed to design and size components to meet American Society for Testing
and Materials test standard E2368 with minimal cost. The resulting design consists
of an Arduino micro controller that reads instrumentation signals and a package of
components that do not rely on interfacing with external software or hardware to
perform a thermomechanical fatigue test. The specific test system hardware components
consist of a 10 kW induction heater, industrial chiller for induction coil operation,
cooling flow nozzles coupled with an air compressor, thermocouples mounted
outside the gauge section, an infrared pyrometer for temperature monitoring within
the specimen gauge section, and an axial extensometer to synchronize the thermal
and mechanical loading cycles. Validation of the system is completed by evaluating
the synchronization of thermal and mechanical loading cycles over a test matrix
with varying cycle times and loading parameters. The system operation follows a
set mechanical load and alters the thermal profile in response to match the profiles.
Initial experiments were conducted to tune heating and cooling process parameters
to achieve minimal load variance between mechanical and thermal loading profiles.
Subsequent experiments characterized response time variance at different loading cycle
frequencies and amplitudes. From experimental testing, it was determined the
system control scheme is correctly designed with existing components to maintain
synchronization within a certain frequency band and amplitude band for an indefinite
number of cycles. This study enables development of fatigue model validation
for predicting needed preventative maintenance, and improving supply chain management.
Further recommendations for this system may include an improved induction
heater that uses digital active control to regulate power output magnitude and an
improved air cooling system to regulate air flow rate in real time
AFB1 and 5 act maternally outside the seed to promote seed growth in Arabidopsis
No full textThe plant hormone auxin in maternal tissues plays a major role in promoting seed growth. However, whether auxin affects seed growth in maternal tissues in or outside the seed is unclear. In the process of investigating the roles of the SKP1-CULLIN-F- BOX (SCF) ubiquitin ligases in Arabidopsis reproductive development, using protein extracts from inflorescence tissues, we found that, among the six auxin receptors, only AUXIN SIGNALING F-BOX1 (AFB1) and 5 (AFB5) were consistently co- immunoprecipitated with the ARABIDOPSIS SKP1-LIKE1 protein. This result suggests that AFB1 and 5 play major roles in reproductive development. We then found that seeds from afb1 and 5 mutants exhibited reduced sizes (weights). The largest reduction in seed weight occurred in afb5-6; the average weight/1000 dry seeds of afb5-6 was approximately 76% of that of the wild type. The seed weights were further investigated in AFB1 and AFB5 transgenic plants with the transgenes driven by their respective promoters or the ASK1 promoter. The results from the T₂ seeds and homozygous T₃ and T₄ seeds suggest that the wild-type levels of the two transcripts are not limiting for seed growth and farther increasing their levels adversely affects seed growth. Histochemical studies of transgenic plants harboring the AFB1:GUS or AFB5:GUS transgene revealed that AFB1 and AFB5 are not expressed in the seed but in the vascular tissue in the fruit wall and the funiculus. Taken together, these results show that AFB1 and AFB5 promote seed growth in maternal tissues outside the seed.Plant Biology, Ecology and Evolutio
Certified management accountant
No full textMany people pursuing a degree in accounting are familiar about the CPA but many people don't know about the Certified Management Accountant (CMA). The CMA certification demonstrates that you can make business decisions for a company while increasing the capacity to communicate efficiently throughout the organization. Many people go on to have great careers with the certification like becoming a controller, cost accountant, CFO, and etc. There are two parts on the CMA exam and each part has 6 sections. Because there are so many sections for each part of the CMA there was a study plan that I followed so that I could stay consistent on my studies. The CMA is a difficult exam and having one can really benefit your career down the road
Nonequilibrium dynamics and indirect microscopy in a three-dimensional spinor Bose-Hubbard model quantum simulator
No full textQuantum simulators are easily controllable quantum systems that allow us to physically model the behavior of more complex systems, that are intractable with even the most advanced supercomputers, to gain insight into their behavior. Using lattice confined spinor Bose-Einstein condensates (BEC) as quantum simulators, we explore the quantum critical dynamics of the superfluid to Mott insulator phase transition in a three-dimensional cubic optical lattice. Our observations reveal that, in a quantum version of the Kibble-Zurek mechanism, the dynamics can be frozen by a sufficiently quick ramp across the transition. Additionally, we utilize discrete energy signatures in nonequilibrium spin mixing dynamics generated by atoms that are tightly confined to single lattice sites after a quench across this transition to understand the spatial dynamics of a BEC during this transition. This "indirect microscopy" method is required to determine the spatial distribution because achieving single lattice site resolved imaging of three dimensional lattice confined quantum gases remains experimentally challenging even with advanced quantum gas microscopy methods. The observed number distributions additionally demonstrate that it may be possible to design lattice ramp sequences to manipulate the distribution of atoms to enhance desired effects.Next, I briefly describe our experiments utilizing a one-dimensional moving optical lattice. Due to the presence of a skew external harmonic confinement the application of the moving lattice induces violent spatial dynamics that are nevertheless accompanied by coherent spin dynamics. We also utilize this system to simulate a six-state tunneling model in which two momentum states are coupled by the lattice velocity while simultaneously the three Zeeman components are coupled by the spin dependent interaction. We observe nonlinear tunneling behavior and note that the six-state tunneling model collapses into effective two-state tunneling models under certain conditions such as highly adiabatic lattice accelerations. I will then discuss the theoretical background of our future work utilizing a stationary lattice with a time dependent lattice depth to expand spinor dynamics to a much wider range of magnetic fields than accessible by conventional experiments and demonstrate that driven lattices may offer a powerful tool capable of simultaneously tuning multiple key parameters that determine spinor physics. Finally, I will discuss the progress we have made in a project to achieve single lattice site imaging resolution in our system, as well as the experimental challenges we have encountered and a proposed solution to these challenges
Deciphering the role of the INI-1 protein within the SWI/SNF remodeling complex
No full textINI-1 is a core subunit of the SWI/SNF chromatin remodeling complex, which stands for SWItch/Sucrose Non-Fermentable, and is a known tumor suppressor gene. INI-1 is a 47kDa long protein with 385 amino acids present in its sequence. It's expressed ubiquitously in all cell types including developmental cells (Fagerberg). It is primarily found in the nucleus, but can be found in small concentrations in the cytoplasm. The mechanism behind the SWI/SNF complex work is still being discovered and not much is known about the role of INI-1 in the complex. 20% of cancer cells contain a mutation in the SWI/SNF complex and a specific type of cancer, Atypical Teratoid Rhadboid Tumors are classified by their lack of INI-1 in the cell (Kim). This report documents how CRISPR-Cas9 was utilized to create INI-1 knockout cells along with developing mononucleosomes to measure how INI-1 affects nucleosome movement. In future studies, the INI-1 knockout cells will be used to compare the cell proliferation and protein expression between the presence and absence of INI-1 in cancer cells. The mononucleosomes will be used to identify the role that INI-1 plays on nucleosomes movement
BDNF levels affected by the synthetic cannabinoid WIN55,212-2 in adolescent rats
No full textCannabinoids are molecules that bind to endocannabinoid receptors (eCBRs) CB1 and CB2 present in the central and peripheral nervous system. The synthetic CB1 receptor agonist WIN55,212-2 (WIN) emulates the effects of delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis. Interestingly, endocannabinoids and neurotrophins, play critical roles in mood, immune and endocrine homeostasis, stress/anxiety response, and neuroplasticity. Endocannabinoids (eCBs) and neurotrophins, particularly brain derived neurotrophic factor (BDNF), are potent neuromodulators that play critical roles in many behavioral and physiological processes. Disruption of either BDNF or endocannabinoid signaling is associated with an overlapping set of neurologic and psychiatric diseases. The chronic use of synthetic cannabinoids during adolescence, a vulnerable stage for brain development may affect or alter the homeostasis and neuroplasticity dependent on BDNF. Therefore, we evaluated the effect of adolescent exposure to WIN on blood and brain [periaqueductal gray (PAG), prefrontal cortex (PFC), hippocampus, and cerebellum] concentration levels of BDNF.Methods: adolescent rats received 5 twice-daily injections of saline (1 mL/kg i.p.) or WIN55,212-2 (0.8 mg/kg i.p.) every other day. Brains and truncal blood were collected, and ELISA immunoassay was used to determine pro and mature BDNF levels.Results: One way ANOVA revealed that WIN increased proBDNF [F 1,11= 12.57, p<0.05] and mBDNF levels [F 1,11= 2.63, p<0.05] in the dorsolateral PAG and periphery [F 1,11= 5.15, p<0.05]. PFC, hippocampus, and cerebellum results are being processed.Discussion: The chronic exposure of synthetic cannabinoid WIN during adolescence modifies the proBDNF/mBDNF ratio in the dorsal PAG and periphery, suggesting that proBDNF/mBDNF ratio are involved in endocannabinoid-mediated adolescence brain plasticity
Cultural translation and museum exhibitions: A case study of modern Korean art at the Los Angeles County Museum of Art
No full textPresenting a case study of an exhibition of modern Korean art at the Los Angeles County Museum of Art, this thesis interrogates the practices and threads of power that shape exhibitions and visitor interpretation in translating works of foreign cultures. Staged at LACMA in 2022, The Space Between: The Modern in Korean Art claimed to be the first exhibition of its kind in the West, presenting works from 1897-1965 in cooperation with the National Museum of Modern and Contemporary Art, Korea. Throughout this era of tumultuous politics, brutal colonization, and the violence of war, Korean artists demonstrated incredible resilience and adaptability. This thesis approaches the exhibition as it shapes comprehensive narratives of Korean modernism and presents them for the first time to an American audience. It interrogates the selection, display, organization, translation, and interpretation of works. It additionally examines various omissions made in the selection process, particularly in the interpretation provided to audiences to contextualize and understand the works on display and their enduring legacy in Korean culture. Some possible reasons for the selections and omissions of the exhibitions are then presented in relation to curatorial practice, soft power, national branding, globalization, museum education practices, and sponsor interests.This thesis will first provide a comprehensive literature review of the prevailing theories and histories that informed the topic. Then, the exhibition will be presented as it would be experienced by average viewers, using only the works on display, organization, and interpretive tools provided by the exhibition to study the thesis of the show. The exhibition will then be re-visited with supplemental research and greater contextualization for the era and artists on display, and will interrogate omissions and the weight of these decisions. This thesis will conclude on a discussion on the layered threads of power that shape exhibitions of foreign culture and in turn shape public opinion on said cultures