UKnowledge Copyright (c) 2019 University of Kentucky All rights reserved. https://uknowledge.uky.edu Recent documents in UKnowledge en-us Tue, 24 Sep 2019 04:53:08 PDT 3600 Sustainable Stewardship: A Collaborative Model for Engaged Oral History Pedagogy, Community Partnership, and Archival Growth https://uknowledge.uky.edu/libraries_facpub/306 https://uknowledge.uky.edu/libraries_facpub/306 Mon, 23 Sep 2019 16:46:28 PDT Our University of Kentucky team of professors, archivists, and oral historians have collaborated since 2013 to develop pedagogy that enables students to encounter and engage oral history, archival materials, and local community in meaningful ways. Through the impetus of the Jewish Kentucky Oral History Project and several semesters of collaboration and iterative syllabus design, we developed “sustainable stewardship” as a replicable model for course and project design to engage undergraduates in original knowledge production while simultaneously fostering archival access and growth. In this article we trace the evolving pedagogical conversations inspired by the classroom introduction of OHMS (Oral History Metadata Synchronizer), the questions of continuity they elicit, and our team’s development of sustainable stewardship to respond to those questions. We argue that sustainable stewardship provides a model to connect the classroom, community, and the archive in enduring, mutually beneficial, and transformative ways.

]]> Janice W. Fernheimer et al. CAREGIVERS OF PARENTS WITH AlZHEIMER’S DISEASE: QUALITY OF LIFE FOR CAREGIVERS: PERSPECTIVES & FAMILY DYNAMICS https://uknowledge.uky.edu/hes_etds/75 https://uknowledge.uky.edu/hes_etds/75 Fri, 20 Sep 2019 10:18:57 PDT This study furthers Alzheimer’s family literature regarding the impact of caregiver attachment, readiness to provide care, and caregiver quality of life. A sample of 33 participants caring for a parent with Alzheimer’s disease in the state of Kentucky was recruited to complete a questionnaire for the study. The questionnaire consisted of an online survey about participants’ experiences and attachments growing up with their parents, their experiences becoming caregivers to their parents with Alzheimer’s disease, and participants’ current perspectives of their own quality of life. Positive perspectives in regards to quality of life among caregivers seem to be a predictor of both stronger readiness to care and stronger attachments. These finding inform therapists about the importance of recognizing a caregiver’s presenting problems of burden and their significance to attachment and readiness to provide such care. This recognition may impact therapy to strengthen a caregiver’s positive adaption, thus it may also decrease burden.

]]> Matthew Cornu Polymer Gels with Tunable Ionic Seebeck Coefficient for Ultra-Sensitive Printed Thermopiles https://uknowledge.uky.edu/physastron_facpub/653 https://uknowledge.uky.edu/physastron_facpub/653 Fri, 20 Sep 2019 08:45:57 PDT Measuring temperature and heat flux is important for regulating any physical, chemical, and biological processes. Traditional thermopiles can provide accurate and stable temperature reading but they are based on brittle inorganic materials with low Seebeck coefficient, and are difficult to manufacture over large areas. Recently, polymer electrolytes have been proposed for thermoelectric applications because of their giant ionic Seebeck coefficient, high flexibility and ease of manufacturing. However, the materials reported to date have positive Seebeck coefficients, hampering the design of ultra-sensitive ionic thermopiles. Here we report an “ambipolar” ionic polymer gel with giant negative ionic Seebeck coefficient. The latter can be tuned from negative to positive by adjusting the gel composition. We show that the ion-polymer matrix interaction is crucial to control the sign and magnitude of the ionic Seebeck coefficient. The ambipolar gel can be easily screen printed, enabling large-area device manufacturing at low cost.

]]> Dan Zhao et al. Multi-Ancestry Study of Blood Lipid Levels Identifies Four Loci Interacting with Physical Activity https://uknowledge.uky.edu/epidemiology_facpub/55 https://uknowledge.uky.edu/epidemiology_facpub/55 Fri, 20 Sep 2019 08:39:41 PDT Many genetic loci affect circulating lipid levels, but it remains unknown whether lifestyle factors, such as physical activity, modify these genetic effects. To identify lipid loci interacting with physical activity, we performed genome-wide analyses of circulating HDL cholesterol, LDL cholesterol, and triglyceride levels in up to 120,979 individuals of European, African, Asian, Hispanic, and Brazilian ancestry, with follow-up of suggestive associations in an additional 131,012 individuals. We find four loci, in/near CLASP1, LHX1, SNTA1, and CNTNAP2, that are associated with circulating lipid levels through interaction with physical activity; higher levels of physical activity enhance the HDL cholesterol-increasing effects of the CLASP1, LHX1, and SNTA1 loci and attenuate the LDL cholesterol-increasing effect of the CNTNAP2 locus. The CLASP1, LHX1, and SNTA1 regions harbor genes linked to muscle function and lipid metabolism. Our results elucidate the role of physical activity interactions in the genetic contribution to blood lipid levels.

]]> Tuomas O. Kilpeläinen et al. Shared Heritability and Functional Enrichment Across Six Solid Cancers https://uknowledge.uky.edu/markey_facpub/139 https://uknowledge.uky.edu/markey_facpub/139 Fri, 20 Sep 2019 08:35:00 PDT Quantifying the genetic correlation between cancers can provide important insights into the mechanisms driving cancer etiology. Using genome-wide association study summary statistics across six cancer types based on a total of 296,215 cases and 301,319 controls of European ancestry, here we estimate the pair-wise genetic correlations between breast, colorectal, head/neck, lung, ovary and prostate cancer, and between cancers and 38 other diseases. We observed statistically significant genetic correlations between lung and head/neck cancer (rg = 0.57, p = 4.6 × 10−8), breast and ovarian cancer (rg = 0.24, p = 7 × 10−5), breast and lung cancer (rg = 0.18, p =1.5 × 10−6) and breast and colorectal cancer (rg = 0.15, p = 1.1 × 10−4). We also found that multiple cancers are genetically correlated with non-cancer traits including smoking, psychiatric diseases and metabolic characteristics. Functional enrichment analysis revealed a significant excess contribution of conserved and regulatory regions to cancer heritability. Our comprehensive analysis of cross-cancer heritability suggests that solid tumors arising across tissues share in part a common germline genetic basis.

]]> Xia Jiang et al. LEARNING TO WRITE IN AN ACADEMIC GENRE: ADULT ENGLISH LEARNERS’ USE OF SOCIOCULTURAL RESOURCES https://uknowledge.uky.edu/edc_etds/26 https://uknowledge.uky.edu/edc_etds/26 Fri, 20 Sep 2019 06:30:18 PDT In this multiple case study, I examined what types of sociocultural resources adult English learners brought with them from their previous contexts and what new resources they drew upon in the U.S. while learning to write in the essay genre. The study also identified how the participants chose to use previous and new sociocultural resources as mediated by the essay genre in the U.S. The following research foci shaped this study: (1) What types of sociocultural resources do adult English learners use while learning to write in the essay genre prior to and after their arrival in the U.S.? (2) How does the essay genre mediate adult English learners’ choices about sociocultural resources in the U.S.?

Data collection involved semi-structured interviews, in-class and out-of-class participant observations and collection of artifacts over a period of seven weeks. Six weeks were dedicated to essay writing in an English composition course and English workshop, and one week was used to conduct a final in-depth interview with each participant. Analysis of data included coding and theme analysis. Four refugee students with diverse cultural backgrounds and who had different contacts within the educational system in the U.S. participated in the study.

Results indicate that the participants relied upon seven categories of social, symbolic, and material resources when they learned to write in the essay genre. The categories are not mutually exclusive, but they do capture the variety of resources participants drew upon as writers in the essay genre prior to and after their arrival in the U.S. To draw upon their resources in the U.S., the participants also made choices that resulted in three types of actions. Those actions included losses, retentions, and gains. The essay genre mediated some retentions and gains. Those choices were driven by the essay genre demands of the participants’ new sociocultural context and, consequently, were rooted in their interaction within the new environment. Not all of the participants’ choices were mediated by the essay genre; some of them were shaped by contextual influences. Contextual influences shaped losses, as well as some of their retentions and gains. Those were general choices that were situated within particular contextual realities.

As my study shows, the essay genre along with context played a significant role in contributing to shaping participant’s agentive capacity. The essay genre, in particular, shaped the kind of competencies they had to demonstrate; contextual influences shaped the types of resources and their access to them. Understanding this interaction and, in particular, how genre helps students make purposeful choices and act as competent writers contributes to a more holistic understanding of learning to write as a sociocultural act. Implications for theory, research, and practice are discussed.

]]> Lyudmyla Ivanyuk Genotype-Phenotype Study in Patients with Valosin-Containing Protein Mutations Associated with Multisystem Proteinopathy https://uknowledge.uky.edu/neurology_facpub/33 https://uknowledge.uky.edu/neurology_facpub/33 Thu, 19 Sep 2019 12:28:18 PDT Mutations in valosin‐containing protein (VCP), an ATPase involved in protein degradation and autophagy, cause VCP disease, a progressive autosomal dominant adult onset multisystem proteinopathy. The goal of this study is to examine if phenotypic differences in this disorder could be explained by the specific gene mutations. We therefore studied 231 individuals (118 males and 113 females) from 36 families carrying 15 different VCP mutations. We analyzed the correlation between the different mutations and prevalence, age of onset and severity of myopathy, Paget's disease of bone (PDB), and frontotemporal dementia (FTD), and other comorbidities. Myopathy, PDB and FTD was present in 90%, 42% and 30% of the patients, respectively, beginning at an average age of 43, 41, and 56 years, respectively. Approximately 9% of patients with VCP mutations had an amyotrophic lateral sclerosis (ALS) phenotype, 4% had been diagnosed with Parkinson's disease (PD), and 2% had been diagnosed with Alzheimer's disease (AD). Large interfamilial and intrafamilial variation made establishing correlations difficult. We did not find a correlation between the mutation type and the incidence of any of the clinical features associated with VCP disease, except for the absence of PDB with the R159C mutation in our cohort and R159C having a later age of onset of myopathy compared with other molecular subtypes.

]]> Ebaa Al-Obeidi et al. Adult Age of Onset Aged Alzheimer Disease Amyotrophic Lateral Sclerosis Cohort Studies Family Health Female Genetic Predisposition to Disease Genotype Humans Male Middle Aged Mutation Parkinson Disease Phenotype Valosin Containing Protein Young Adult EVALUATION OF CURRENT AND EMERGING TECHNIQUES FOR MEASURING EGGSHELL INTEGRITY OF THE DOMESTIC FOWL https://uknowledge.uky.edu/animalsci_etds/108 https://uknowledge.uky.edu/animalsci_etds/108 Thu, 19 Sep 2019 12:09:23 PDT This dissertation is an investigation into the effect of different zinc sources and levels on eggshell quality and microstructure, as well as keel bone damage. Eggshell function is two-fold; eggshells function to protect the developing embryo, as well as act as a barrier against bacterial penetration, optimizing food safety of the egg for human consumption (Mabe et. Al., 2003). Two small trials were conducted in order to determine differences in eggshell microstructure of eggs produced from hens at peak lay (26 weeks of age) and at the end of lay (88 weeks of age). Two groups of hens were fed a calcium sufficient or a calcium deficient diet. From this it was determined that eggs with higher breaking strengths had some differences in eggshell microstructure. Eggs with greater breaking strengths had a greater density of ‘normal’ structures, compared to ‘abnormal’ structures. Additionally, eggs requiring a greater breaking force, had a thicker micro-structure, compared to shells requiring less breaking force. With this knowledge on microstructure, a larger, 36-week study was conducted using different zinc sources. Every four weeks, eggs were collected and standard egg quality measurements were taken and keel bones were scored. At the end of the study, keel bones were collected from randomly selected hens representing each treatment. Picture of these keel bones were taken and measurements were taken to determine type and degree of deformation, in comparison to scores taken on the live bird. Pens selected for keel bone analysis, were the same pens that eggs were taken for imaging by the scanning electron microscope, to determine eggshell microstructure. From this data, it was determined that egg quality differences were detected, as well as differences in eggshell microstructure. Additionally, keel bone scores progressively worsened throughout the 36-week long study, with type and degree of deformation differing depending on zinc source.

]]> Lauren Wood Nolan Carisbamate Blockade of T-Type Voltage-Gated Calcium Channels https://uknowledge.uky.edu/scobirc_facpub/32 https://uknowledge.uky.edu/scobirc_facpub/32 Thu, 19 Sep 2019 11:18:16 PDT Objectives

Carisbamate (CRS) is a novel monocarbamate compound that possesses antiseizure and neuroprotective properties. However, the mechanisms underlying these actions remain unclear. Here, we tested both direct and indirect effects of CRS on several cellular systems that regulate intracellular calcium concentration [Ca2+]i.

Methods

We used a combination of cellular electrophysiologic techniques, as well as cell viability, Store Overload‐Induced Calcium Release (SOICR), and mitochondrial functional assays to determine whether CRS might affect [Ca2+]i levels through actions on the endoplasmic reticulum (ER), mitochondria, and/or T‐type voltage‐gated Ca2+ channels.

Results

In CA3 pyramidal neurons, kainic acid induced significant elevations in [Ca2+]i and long‐lasting neuronal hyperexcitability, both of which were reversed in a dose‐dependent manner by CRS. Similarly, CRS suppressed spontaneous rhythmic epileptiform activity in hippocampal slices exposed to zero‐Mg2+ or 4‐aminopyridine. Treatment with CRS also protected murine hippocampal HT‐22 cells against excitotoxic injury with glutamate, and this was accompanied by a reduction in [Ca2+]i. Neither kainic acid nor CRS alone altered the mitochondrial membrane potential (ΔΨ) in intact, acutely isolated mitochondria. In addition, CRS did not affect mitochondrial respiratory chain activity, Ca2+‐induced mitochondrial permeability transition, and Ca2+ release from the ER. However, CRS significantly decreased Ca2+ flux in human embryonic kidney tsA‐201 cells transfected with Cav3.1 (voltage‐dependent T‐type Ca2+) channels.

Significance

Our data indicate that the neuroprotective and antiseizure activity of CRS likely results in part from decreased [Ca2+]i accumulation through blockade of T‐type Ca2+ channels.

]]> Do Young Kim et al. Animals Anticonvulsants Calcium Calcium Channels, T-Type Carbamates Cell Survival Cells, Cultured Dose-Response Relationship, Drug Excitatory Amino Acid Agonists Glutamic Acid HEK293 Cells Hippocampus Humans In Vitro Techniques Kainic Acid Male Membrane Potential, Mitochondrial Mice Neurons Patch-Clamp Techniques Piperidines Potassium Channel Blockers Spectrometry, Fluorescence Transfection Micro-Raman Imaging of Isomeric Segregation in Small-Molecule Organic Semiconductors https://uknowledge.uky.edu/chemistry_facpub/160 https://uknowledge.uky.edu/chemistry_facpub/160 Thu, 19 Sep 2019 10:57:04 PDT Charge transport in organic semiconductors is highly sensitive to film heterogeneity and intermolecular interactions, but probing these properties on the length scales of disorder is often difficult. Here we use micro-Raman spectroscopy to assign vibrational modes of isomerically pure syn and anti 2,8-difluoro-5,11-bis(triethylsilylethynyl)anthradithiophene (diF-TES ADT) by comparing to density functional theory calculations. With polarization-dependent measurements, we determine the orientation of crystallites in pure isomers. In mixed-isomer samples, we observe narrow linewidths and superposition spectra, indicating coexistence of isomerically pure sub-domains on length scales smaller than the probe area. Using the ring breathing modes close to 1300 cm−1 as indicators of the pure isomer crystalline sub-domains, we image their spatial distribution with 200-nm resolution. These results demonstrate the power of micro-Raman spectroscopy for investigating spatial heterogeneities and clarifying the origin of the reduced charge carrier mobility displayed in mixed-isomer diF-TES ADT.

]]> Chiung-Wei Huang et al. Optimization of Induction Quenching Processes for HSS Roll Based on MMPT Model https://uknowledge.uky.edu/cme_facpub/68 https://uknowledge.uky.edu/cme_facpub/68 Thu, 19 Sep 2019 10:51:33 PDT To improve the comprehensive performance of high speed steel (HSS) cold rolls, the induction hardening processes were analyzed by numerical simulation and experimental research. Firstly, a modified martensitic phase transformation (MMPT) model of the tested steel under stress constraints was established. Then, the MMPT model was fed into DEFORM to simulate the induction quenching processes of working rolls based on an orthogonal test design and the optimal dual frequency of the induction quenching process was obtained. The results indicate that the depth of the roll’s hardened layer increases by 32.5% and the axial residual tensile stress also becomes acceptable under the optimized process. This study provides guidance for studying phase transformation laws under stress constraints and the optimization of complex processes in an efficient manner.

]]> Ligang Liu et al. Limit Equilibrium Method-Based Shear Strength Prediction for Corroded Reinforced Concrete Beam with Inclined Bars https://uknowledge.uky.edu/me_facpub/65 https://uknowledge.uky.edu/me_facpub/65 Thu, 19 Sep 2019 10:44:11 PDT Shear strength is a widely investigated parameter for reinforced concrete structures. The corrosion of reinforcement results in shear strength reduction. Corrosion has become one of the main deterioration factors in reinforced concrete beam. This paper proposes a shear strength model for beams with inclined bars based on a limit equilibrium method. The proposed model can be applied to both corroded and uncorroded reinforced concrete beams. Besides the tensile strength of longitudinal steel bars, the shear capacity provided by the concrete on the top of the diagonal crack, the tensile force of the shear steel at the diagonal crack, the degradation of the cross-sectional area and strength of the reinforcements induced by corrosion are all considered. An experimental work on two groups accelerated corroded beams was performed. Good agreements were found between the proposed theoretical predictions and experimental observations.

]]> Yafei Ma et al. Near-Surface Material Phases and Microstructure of Scandate Cathodes https://uknowledge.uky.edu/cme_facpub/67 https://uknowledge.uky.edu/cme_facpub/67 Thu, 19 Sep 2019 10:39:47 PDT Scandate cathodes that were fabricated using the liquid-solid process and that exhibited excellent emission performance were characterized using complementary state-of-the-art electron microscopy techniques. Sub-micron BaAl2O4 particles were observed on the surfaces and edges of tungsten particles, as seen in cross-section samples extracted from the scandate cathode surface regions. Although several BaAl2O4 particles were observed to surround smaller Sc2O3 nanoparticles, no chemical mixing of the two oxides was detected, and in fact the distinct oxide phases were separately verified by chemical analysis and also by 3D elemental tomography. Nanobeam electron diffraction confirmed that the crystal structure throughout W grains is body-centered cubic, indicating that they are metallic W and did not experience noticeable changes, even near the grain surfaces, as a result of the numerous complex chemical reactions that occur during cathode impregnation and activation. 3D reconstruction further revealed that internal Sc/Sc2O3 particles tend to exhibit a degree of correlated arrangement within a given W particle, rather than being distributed uniformly throughout. Moreover, the formation of Sc/Sc2O3 particles within W grains may arise from W surface roughening that occurs during the liquid-solid synthesis process.

]]> Xiaotao Liu et al. Clinical Features, Survival and Prognostic Factors of Glycogen-Rich Clear Cell Carcinoma (GRCC) of the Breast in the U.S. Population https://uknowledge.uky.edu/biochem_facpub/166 https://uknowledge.uky.edu/biochem_facpub/166 Wed, 18 Sep 2019 12:55:16 PDT The World Health Organization (WHO) defines glycogen-rich clear cell carcinoma (GRCC) of the breast as a carcinoma with glycogen accumulation in more than 90% of its tumor cells. Due to the rarity of this disease, its reported survival and clinical associations have been inconsistent due to reliance on case reports and limited case series. As a result, the prognostic implication of this cancer subtype remains unclear. Using the U.S. Surveillance, Epidemiology, and End Results (SEER) program database, we compared the incidence, demographics and prognostic factors of 155 cases of GRCC of the breast to 1,251,584 cases of other (non-GRCC) breast carcinomas. We demonstrate that GRCC is more likely to be identified as high grade, advanced stage, and more likely to have triple negative receptor status. GRCC cases display a poorer prognosis than non-GRCC carcinomas of the breast irrespective of age, AJCC staging, tumor grade, joint hormone receptor/human epidermal growth factor receptor 2 (HER2) status, and treatment. Similar to non-GRCC carcinomas, older age and higher American Joint Committee on Cancer (AJCC)/TNM staging were associated with poorer prognosis for GRCC, while treatment with surgery and radiation were associated with improved survival. Radiation, specifically in the setting of breast-conserving surgery, further improved survival compared to surgery alone. Our study highlights the poorer prognosis associated with glycogen accumulation in breast cancers and hence stresses the importance of identifying this more aggressive tumor type.

]]> Zhengqiu Zhou et al. Photochemical Properties and Structure-Activity Relationships of Ru<sup>II</sup> Complexes with Pyridylbenzazole Ligands as Promising Anticancer Agents https://uknowledge.uky.edu/chemistry_facpub/159 https://uknowledge.uky.edu/chemistry_facpub/159 Wed, 18 Sep 2019 12:53:08 PDT Ruthenium complexes capable of light‐triggered cytotoxicity are appealing potential prodrugs for photodynamic therapy (PDT) and photoactivated chemotherapy (PACT). Two groups of (polypyridyl)RuII complexes with 2‐(2‐pyridyl)benzazole ligands were synthesized and investigated for their photochemical properties and anticancer activity to compare strained and unstrained systems that are likely to have different biological mechanisms of action. The structure–activity relationship was focused on the benzazole‐core bioisosterism and replacement of coligands in RuII complexes. Strained compounds rapidly ejected the 2‐(2‐pyridyl)benzazole ligand after light irradiation, and possessed strong toxicity in the HL‐60 cell line both under dark and light conditions. In contrast, unstrained RuII complexes were nontoxic in the absence of light, induced cytotoxicity at nanomolar concentrations after light irradiation, and were capable of light‐induced DNA damage. The 90–220‐fold difference in light and dark IC50 values provides a large potential therapeutic window to allow for selective targeting of cells by exposure to light.

]]> Dmytro Havrylyuk et al. Divergence of cAMP Signalling Pathways Mediating Augmented Nucleotide Excision Repair and Pigment Induction in Melanocytes https://uknowledge.uky.edu/markey_facpub/138 https://uknowledge.uky.edu/markey_facpub/138 Wed, 18 Sep 2019 08:39:12 PDT Loss‐of‐function melanocortin 1 receptor (MC1R) polymorphisms are common in UV‐sensitive fair‐skinned individuals and are associated with blunted cAMP second messenger signalling and higher lifetime risk of melanoma because of diminished ability of melanocytes to cope with UV damage. cAMP signalling positions melanocytes to resist UV injury by upregulating synthesis of UV‐blocking eumelanin pigment and by enhancing the repair of UV‐induced DNA damage. cAMP enhances melanocyte nucleotide excision repair (NER), the genome maintenance pathway responsible for the removal of mutagenic UV photolesions, through cAMP‐activated protein kinase (protein kinase A)‐mediated phosphorylation of the ataxia telangiectasia‐mutated and Rad3‐related (ATR) protein on the S435 residue. We investigated the interdependence of cAMP‐mediated melanin upregulation and cAMP‐enhanced DNA repair in primary human melanocytes and a melanoma cell line. We observed that the ATR‐dependent molecular pathway linking cAMP signalling to the NER pathway is independent of MITF activation. Similarly, cAMP‐mediated upregulation of pigment synthesis is independent of ATR, suggesting that the key molecular events driving MC1R‐mediated enhancement of genome maintenance (eg PKA‐mediated phosphorylation of ATR) and MC1R‐induced pigment induction (eg MITF activation) are distinct.

]]> Erin M. Wolf Horrell et al. Ataxia Telangiectasia Mutated Proteins Cell Line, Tumor Cyclic AMP Cyclic AMP-Dependent Protein Kinases DNA Damage DNA Repair Humans Levodopa Melanins Melanocytes Mutagenesis Nucleotides Phosphorylation RNA, Small Interfering Receptor, Melanocortin, Type 1 Serine Signal Transduction Skin Pigmentation Ultraviolet Rays Up-Regulation Incidence and Cost of Acute Kidney Injury in Hospitalized Patients with Infective Endocarditis https://uknowledge.uky.edu/internalmedicine_facpub/197 https://uknowledge.uky.edu/internalmedicine_facpub/197 Wed, 18 Sep 2019 08:32:32 PDT Acute kidney injury (AKI) is a frequent complication of hospitalized patients with infective endocarditis (IE). Further, AKI in the setting of IE is associated with high morbidity and mortality. We aimed to examine the incidence, clinical parameters, and hospital costs associated with AKI in hospitalized patients with IE in an endemic area with an increasing prevalence of opioid use. This retrospective cohort study included 269 patients admitted to a major referral center in Kentucky with a primary diagnosis of IE from January 2013 to December 2015. Of these, 178 (66.2%) patients had AKI by Kidney Disease Improving Global Outcomes (KDIGO) serum creatinine criteria: 74 (41.6%) had AKI stage 1 and 104 (58.4%) had AKI stage ≥ 2. In multivariable analysis, higher comorbidity scores and the need for diuretics were independently associated with AKI, while the involvement of the tricuspid valve and the need for vasopressor/inotrope support were independently associated with severe AKI (stage ≥ 2). The median total direct cost of hospitalization was progressively higher according to each stage of AKI ($17,069 for no AKI; $37,111 for AKI stage 1; and $61,357 for AKI stage ≥ 2; p < 0.001). In conclusion, two-thirds of patients admitted to the hospital due to IE had incident AKI. The occurrence of AKI significantly increased healthcare costs. The higher level of comorbidity, the affection of the tricuspid valve, and the need for diuretics and/or vasoactive drugs were associated with severe AKI in this susceptible population.

]]> Victor Ortiz-Soriano et al. Transcriptional Regulation Factors of the Human Mitochondrial Aspartate/Glutamate Carrier Gene, Isoform 2 (<em>SLC25A13</em>): USF1 as Basal Factor and FOXA2 as Activator in Liver Cells https://uknowledge.uky.edu/biochem_facpub/165 https://uknowledge.uky.edu/biochem_facpub/165 Wed, 18 Sep 2019 08:27:29 PDT Mitochondrial carriers catalyse the translocation of numerous metabolites across the inner mitochondrial membrane, playing a key role in different cell functions. For this reason, mitochondrial carrier gene expression needs tight regulation. The human SLC25A13 gene, encoding for the mitochondrial aspartate/glutamate carrier isoform 2 (AGC2), catalyses the electrogenic exchange of aspartate for glutamate plus a proton, thus taking part in many metabolic processes including the malate-aspartate shuttle. By the luciferase (LUC) activity of promoter deletion constructs we identified the putative promoter region, comprising the proximal promoter (−442 bp/−19 bp), as well as an enhancer region (−968 bp/−768 bp). Furthermore, with different approaches, such as in silico promoter analysis, gene silencing and chromatin immunoprecipitation, we identified two transcription factors responsible for SLC25A13 transcriptional regulation: FOXA2 and USF1. USF1 acts as a positive transcription factor which binds to the basal promoter thus ensuring SLC25A13 gene expression in a wide range of tissues. The role of FOXA2 is different, working as an activator in hepatic cells. As a tumour suppressor, FOXA2 could be responsible for SLC25A13 high expression levels in liver and its downregulation in hepatocellular carcinoma (HCC).

]]> Paolo Convertini et al. Carcinoma, Hepatocellular Gene Expression Regulation, Neoplastic HEK293 Cells Hep G2 Cells Hepatocyte Nuclear Factor 3-beta Humans Liver Neoplasms Mitochondrial Membrane Transport Proteins Promoter Regions, Genetic Transcriptional Activation Upstream Stimulatory Factors The Effects of a Bacterial Endotoxin on Behavior and Sensory-CNS-Motor Circuits in <em>Drosophila melanogaster</em> https://uknowledge.uky.edu/biology_facpub/176 https://uknowledge.uky.edu/biology_facpub/176 Wed, 18 Sep 2019 08:19:51 PDT The effect of bacterial sepsis on animal behavior and physiology is complex due to direct and indirect actions. The most common form of bacterial sepsis in humans is from gram-negative bacterial strains. The endotoxin (lipopolysaccharide, LPS) and/or associated peptidoglycans from the bacteria are the key agents to induce an immune response, which then produces a cascade of immunological consequences. However, there are direct actions of LPS and associated peptidoglycans on cells which are commonly overlooked. This study showed behavioral and neural changes in larval Drosophila fed commercially obtained LPS from Serratia marcescens. Locomotor behavior was not altered, but feeding behavior increased and responses to sensory tactile stimuli were decreased. In driving a sensory-central nervous system (CNS)-motor neural circuit in in-situ preparations, direct application of commercially obtained LPS initially increased evoked activity and then decreased and even stopped evoked responses in a dose-dependent manner. With acute LPS and associated peptidoglycans exposure (10 min), the depressed neural responses recovered within a few minutes after removal of LPS. Commercially obtained LPS induces a transitory hyperpolarization of the body wall muscles within seconds of exposure and alters activity within the CNS circuit. Thus, LPS and/or associated peptidoglycans have direct effects on body wall muscle without a secondary immune response.

]]> Oscar Istas et al. Use of a Cross-Sectional Survey in the Adult Population to Characterize Persons at High-Risk for Chronic Obstructive Pulmonary Disease https://uknowledge.uky.edu/internalmedicine_facpub/196 https://uknowledge.uky.edu/internalmedicine_facpub/196 Wed, 18 Sep 2019 08:16:34 PDT Rationale/Objective: The Behavioral Risk Factor Surveillance System (BRFSS) health survey has been used to describe the epidemiology of chronic obstructive pulmonary disease (COPD) in the US. Through addressing respiratory symptoms and tobacco use, it could also be used to characterize COPD risk. Methods: Four US states added questions to the 2015 BRFSS regarding productive cough, shortness of breath, dyspnea on exertion, and tobacco duration. We determined COPD risk categories: provider-diagnosed COPD as self-report, high-risk for COPD as ≥ 10 years tobacco smoking and at least one significant respiratory symptom, and low risk was neither diagnosed COPD nor high risk. Disease burden was defined by respiratory symptoms and health impairments. Data were analyzed using multiple logistic regression models with age as a covariate. Results: Among 35,722 adults ≥ 18 years, the overall prevalence of COPD and high-risk for COPD were 6.6% and 5.1%. Differences among COPD risk groups were evident based on gender, race, age, geography, tobacco use, health impairments, and respiratory symptoms. Risk for disease was seen early where 3.75% of 25–34 years-old met high-risk criteria. Longer tobacco duration was associated with an increased prevalence of COPD, particularly > 20 years. Seventy-nine percent of persons ≥ 45 years-old with frequent shortness of breath (SOB) reported having or being at risk of COPD, reflecting disease burden. Conclusion: These data, representing nearly 18% of US adults, indicates those at high risk for COPD share many, but not all of the characteristics of persons diagnosed with the disease and demonstrates the value of the BRFSS as a tool to define lung health at a population level.

]]> Roy A. Pleasants et al. The North American Transportation Security Center https://uknowledge.uky.edu/ktc_researchreports/1633 https://uknowledge.uky.edu/ktc_researchreports/1633 Tue, 17 Sep 2019 16:10:58 PDT Steven Douglas Kreis et al. The North American Transportation Security Center – SERRI Analysis Update https://uknowledge.uky.edu/ktc_researchreports/1632 https://uknowledge.uky.edu/ktc_researchreports/1632 Tue, 17 Sep 2019 16:10:29 PDT Executive Summary

There are over 800,000 hazardous materials (hazmat) shipments over the nation’s roads each day. According to the U.S. Department of Homeland Security (DHS), terrorist activity related to the transportation of hazardous materials represents a significant threat to public safety and the nation’s critical infrastructure. Specifically, the federal government has identified the government’s inability to track hazmat shipments on a real-time basis as a significant security vulnerability.

In 2004, the U.S. Federal Motor Carrier Safety Administration (FMCSA) completed a study to determine if “smart truck” technology such as GPS tracking, wireless modems, panic buttons, and on-board computers could be used to enhance hazmat shipment security. The FMCSA study concluded that “smart truck” technology will be highly effective in protecting hazmat shipments from terrorists. The FMCSA study also concluded that “smart truck” technology deployment will produce a huge security benefit and an overwhelmingly positive return on investment for hazmat carriers.

The FMCSA study led to the U.S. Transportation Security Administration’s (TSA) Hazmat Truck Security Pilot (HTSP). This congressionally mandated pilot program was undertaken to demonstrate if a hazmat truck tracking center was feasible from a technology and systems perspective. The HTSP project team built a technology prototype of a hazmat truck tracking system to show that “smart truck” technology could be crafted into an effective and efficient system for tracking hazmat shipments. The HTSP project team also built the Universal Communications Interface – the XML gateway for hazmat carriers to use to provide data to a centralized truck tracking center.

In August 2007, Congress enacted the 9/11 Act (PL110-53) that directs TSA to develop a program - consistent with the Hazmat Truck Security Pilot - to facilitate the tracking of motor carrier shipments of security-sensitive materials. In June 2008, TSA took a major step forward in establishing a national hazmat security program by issuing guidance for shipments of Tier 1 Highway Security Sensitive Materials (HSSMs), the riskiest shipments from a security perspective. TSA’s Tier 1 HSSM guidance includes Security Action Items which specify security measures – including vehicle tracking – that TSA believes are prudent security measures for shippers and carriers to follow. Compliance with TSA’s Tier 1 HSSM guidance is voluntary but TSA is expected to issue regulations based on the Tier 1 HSSM Security Action Items that will make compliance mandatory.

Establishment of a Tier 1 HSSM truck tracking center is critical to implementation of a Tier 1 HSSM regulatory program based on the Security Action items by TSA. The HTSP technology prototype was an excellent first step toward an operational Tier 1 HSSM truck tracking system, however, it falls far short of what TSA needs in an operational system.

The Kentucky Transportation Center at the University of Kentucky completed a study December 2008 that examined market drivers that would influence the design and operation of a Tier 1 HSSM truck tracking system. The study was funded by the South East Region Research Initiative (SERRI).

The objective of this deliverable is to update the SERRI report with a specific focus on two item:

  1. new or enhanced fleet tracking vendor product and service offerings; and
  2. programmatic conditions that have changed since December 2008

]]> Steven Douglas Kreis et al. p-21 Activated Kinase as a Molecular Target for Chemoprevention in Diabetes https://uknowledge.uky.edu/surgery_facpub/38 https://uknowledge.uky.edu/surgery_facpub/38 Tue, 17 Sep 2019 12:56:05 PDT Hypothesis: Anti-diabetic drugs modulate p-21 activated kinase (PAK) signaling. Introduction: Type 2 diabetes mellitus (T2DM) is a chronic inflammatory disease associated with increased cancer risk. PAK signaling is implicated in cellular homeostasis when regulated, and cancer when unrestrained. Recent reports provided a role for PAK signaling in glucose homeostasis, but the role of PAKs in the pathogenesis of T2DM is unknown. Here, we performed a mini-meta-analysis to explore if anti-diabetic drugs modify PAK signaling pathways, and provide insight regarding modulation of these pathways, to potentially reduce diabetes-associated cancer risk. Methods: PAK interacting partners in T2DM were identified using the online STRING database. Correlation studies were performed via systematic literature review to understand the effect of anti-diabetic drugs on PAK signaling. A mini-meta-analysis correlated multiple clinical studies and revealed the overall clinical response rate and percentage of adverse events in piogliazone (n = 53) and metformin (n = 91) treated patients with PAK-associated diseases. Results: A total of 30 PAK interacting partners were identified (10: reduced beta-cell mass; 10: beta-cell dysfunction; 10: obesity-insulin resistance), which were highly associated with Wnt, and G-protein signaling. The anti-diabetic drug metformin activated signaling pathways upstream; whereas pioglitazone inhibited pathways downstream of PAK. Overall, clinical response upon pioglitazone treatment was 53%. Seventy-nine percent of pioglitazone and 75% of metformin treated patients had adverse events. Pioglitazone reduced molecular-PAK biomarkers of proliferation (Ki67 and CyclinD1), and metformin had the opposite effect. Conclusions: PAK signaling in T2DM likely involves Wnt and G-protein signaling, which may be altered by the anti-diabetic drugs metformin and pioglitazone. Apart from the therapeutic limitations of adverse events, pioglitazone may be promising in chemoprevention. However long-term multi-centered studies, which initiate pioglitazone treatment early will be required to fully assess the full potential of these drugs.

]]> Kyle Dammann et al. Highly Thiolated Poly (Beta-Amino Ester) Nanoparticles for Acute Redox Applications https://uknowledge.uky.edu/cme_facpub/66 https://uknowledge.uky.edu/cme_facpub/66 Tue, 17 Sep 2019 12:48:24 PDT Disulfides are used extensively in reversible cross-linking because of the ease of reduction into click-reactive thiols. However, the free-radical scavenging properties upon reduction are often under-considered. The free thiols produced upon reduction of this disulfide material mimic the cellular reducing chemistry (glutathione) that serves as a buffer against acute oxidative stress. A nanoparticle formulation producing biologically relevant concentrations of thiols may not only provide ample chemical conjugation sites, but potentially be useful against severe acute oxidative stress exposure, such as in targeted radioprotection. In this work, we describe the synthesis and characterization of highly thiolated poly (β-amino ester) (PBAE) nanoparticles formed from the reduction of bulk disulfide cross-linked PBAE hydrogels. Degradation-tunable PBAE hydrogels were initially synthesized containing up to 26 wt % cystamine, which were reduced into soluble thiolated oligomers and formulated into nanoparticles upon single emulsion. These thiolated nanoparticles were size-stable in phosphate buffered saline consisting of up to 11.0 ± 1.1 mM (3.7 ± 0.3 mmol thiol/g, n = 3 M ± SD), which is an antioxidant concentration within the order of magnitude of cellular glutathione (1–10 mM).

]]> Andrew L. Lakes et al. MECHANISMS OF TYPE-I IFN INHIBITION: EQUINE HERPESVIRUS-1 ESCAPE FROM THE ANTIVIRAL EFFECT OF TYPE-1 INTERFERON RESPONSE IN HOST CELL https://uknowledge.uky.edu/gluck_etds/43 https://uknowledge.uky.edu/gluck_etds/43 Tue, 17 Sep 2019 10:10:45 PDT Equine herpesvirus-1 (EHV-1) is one of the most important and prevalent viral pathogens of horses causing a major threat to the equine industry throughout most of the world. EHV-1 primarily causes respiratory disease but viral spread to distant organs enables the development of more severe sequelae; abortion and neurologic disease. In order to produce disease, EHV-1 has to overcome the innate barrier of the type-I interferon (IFN) system in host cells. However, the underlying mechanisms employed by EHV-1 to circumvent the type-I IFN response in host cells are not well understood. In this project study, using molecular techniques, we explored how EHV-1 is able to escape the type-I IFN response in host cells during infection. We also investigated whether EHV-4, a closely related but less pathogenic virus, has similar effects on type-I IFN as a clue to understanding how widespread IFN suppressive function is found among equine alphaherpesviruses.

Our data showed that inhibition of the type-I IFN response in host cells is not a function of neuropathogenicity of EHV-1 strains. However, a reduced type-I IFN response correlated with pathogenicity as EHV-4, unlike EHV-1, was unable to down-regulate the type-I IFN response in equine endothelial cells (EECs). Investigation of the mechanisms employed by EHV-1 to suppress type-I IFN revealed that the virus sequentially prevented outside-in signaling events that lead to type-I IFN production. Specifically, EHV-1 blocked the expression of Toll-like receptors (TLR) 3 and TLR4 at 6 hours post-infection (hpi) and 12 hpi. EHV-1 also prevented the transcription of IRF7 and IRF9 at different time-points during infection. The virus also perturbed the JAK-STAT signaling pathway by negatively regulating the cellular levels of TYK2 and phosphorylation-mediated activation of STAT2 molecules. Immunofluorescence data revealed that during infection, EHV-1 was able to sequester STAT2 molecules from nuclear translocation. This may be a limiting step preventing the formation of interferon- stimulated gene factor 3 (ISGF3) whose nuclear translocation is required to transactivate interferon-stimulated genes (ISGs) including IRF7.

Further investigation showed that unlike EHV-1, EHV-4 only interfered with phosphorylation-mediated activated STAT1 and STAT2 molecules at 3 and 6 hpi. EHV-4 was unable to block TLR3/4 and IRF7/9 mRNA expression at any time-point. Intriguingly, while viral late gene of EHV-1 mediates inhibition of STAT phosphorylation, our data showed that for EHV-4, a virus late gene did not mediate the inhibition of STAT phosphorylation. The findings from this study help illuminate how EHV-1 strategically interferes with limiting steps required for type-I IFN response in host cells to promote pathology. Our data also strengthen the hypothesis that the ability to shut off host factors required for type-I IFN production might be directly related to the degree of pathogenicity of the EHV subtypes.

]]> Fatai S. Oladunni Complement 3a Receptor in Dorsal Horn Microglia Mediates Pronociceptive Neuropeptide Signaling https://uknowledge.uky.edu/physiology_facpub/143 https://uknowledge.uky.edu/physiology_facpub/143 Tue, 17 Sep 2019 09:26:27 PDT The complement 3a receptor (C3aR1) participates in microglial signaling under pathological conditions and was recently shown to be activated by the neuropeptide TLQP‐21. We previously demonstrated that TLQP‐21 elicits hyperalgesia and contributes to nerve injury‐induced hypersensitivity through an unknown mechanism in the spinal cord. Here we determined that this mechanism requires C3aR1 and that microglia are the cellular target for TLQP‐21. We propose a novel neuroimmune signaling pathway involving TLQP‐21‐induced activation of microglial C3aR1 that then contributes to spinal neuroplasticity and neuropathic pain. This unique dual‐ligand activation of C3aR1 by a neuropeptide (TLQP‐21) and an immune mediator (C3a) represents a potential broad‐spectrum mechanism throughout the CNS for integration of neuroimmune crosstalk at the molecular level.

]]> Suzanne Doolen et al. Analysis of Variance Animals Calcium Calcium-Binding Proteins Cells, Cultured Disease Models, Animal Green Fluorescent Proteins Hyperalgesia In Vitro Techniques Mice Mice, Inbred C57BL Mice, Transgenic Microfilament Proteins Microglia Neuralgia Pain Threshold Peptide Fragments RNA, Messenger Receptors, Complement Signal Transduction Spinal Cord Dorsal Horn Myelin as an Inflammatory Mediator: Myelin Interactions with Complement, Macrophages, and Microglia in Spinal Cord Injury https://uknowledge.uky.edu/scobirc_facpub/31 https://uknowledge.uky.edu/scobirc_facpub/31 Tue, 17 Sep 2019 09:11:53 PDT Spinal cord injury (SCI) triggers chronic intraspinal inflammation consisting of activated resident and infiltrating immune cells (especially microglia/macrophages). The environmental factors contributing to this protracted inflammation are not well understood; however, myelin lipid debris is a hallmark of SCI. Myelin is also a potent macrophage stimulus and target of complement‐mediated clearance and inflammation. The downstream effects of these neuroimmune interactions have the potential to contribute to ongoing pathology or facilitate repair. This depends in large part on whether myelin drives pathological or reparative macrophage activation states, commonly referred to as M1 (proinflammatory) or M2 (alternatively) macrophages, respectively. Here we review the processes by which myelin debris may be cleared through macrophage surface receptors and the complement system, how this differentially influences macrophage and microglial activation states, and how the cellular functions of these myelin macrophages and complement proteins contribute to chronic inflammation and secondary injury after SCI.

]]> Timothy J. Kopper et al. Potential Economic Impacts of Allocating More Land for Bioenergy Biomass Production in Virginia https://uknowledge.uky.edu/forestry_facpub/37 https://uknowledge.uky.edu/forestry_facpub/37 Tue, 17 Sep 2019 09:03:31 PDT The growing attention to renewable energy and rural development has created greater demand for production of biomass feedstock for bioenergy. However, forest growth rates and the amount of land in most existing forests may not be sufficient to sustainably supply the forest biomass required to support existing forest products industries and the expanding bioenergy industry. Additionally, concerns about agricultural land use competition have dampened expansion of biomass production on agricultural land base. One of the ways to meet the growing forest biomass feedstock demand for bioenergy production is by allocating currently marginal non-forested land for growing bioenergy feedstocks. In Virginia, about 80% of forestland is under nonindustrial private forest ownership. The land use allocation decisions of these private owners are critical for the supply of the forest biomass feedstock to support bioenergy production. We apply a computable general equilibrium model to assess the economy-wide impacts of forestland owners’ willingness to plant pine on non-forested land for woody bioenergy in Virginia. We consider three counterfactual scenarios of biomass feedstock supply increase as intermediate demand for bioenergy production based on forestland owners’ willingness to accept biomass bid prices to set aside more non-forested land for biomass production in Virginia under general equilibrium conditions. Overall, the results show an increase in social welfare and household utility but a marginal decline in GDP. However, increased demand of biomass from logging sector depressed the manufacturing sector (the wood manufacturing sub-sector particularly), which also relies on the logging sector for its intermediate inputs. Results from this study provide insights into the bioenergy land use competition debate, and pathways towards sustainable bioenergy feedstock supply.

]]> Thomas O. Ochuodho et al. Wildfire Alters Spatial Patterns of Available Soil Nitrogen and Understory Environments in a Valley Boreal Larch Forest https://uknowledge.uky.edu/forestry_facpub/36 https://uknowledge.uky.edu/forestry_facpub/36 Tue, 17 Sep 2019 08:56:54 PDT Wildfire, a primary natural disturbance in many forests, affects soil nutrient availability and spatial distributions of forest plants. However, post-fire changes in soil nutrients and spatial patterns of understory environments at fine scales are poorly understood. Here, we characterized spatial patterns of soil nitrogen availability and site characteristics at a 3-year-post-fire and an unburned site in a valley boreal larch forest. We also examined the relationship between soil nitrogen availability and site characteristics. The results showed that the burned site had higher NO3− and lower NH4+ than the control. The herb, litter and coarse wood debris cover was greater at the burned site than at the control site with higher soil pH, depth of the organic horizon (DOH) and shrub cover. Relative variability (coefficient of variation) in soil nitrogen and site characteristic variables at the control site was greater than at the burned site except for shrub and regeneration tree seedling cover. Spatial structure (quantified by semi-variograms) was lacking for soil nitrogen and site characteristic variables except for DOH, herb and shrub cover at the control site, but wildfire created a strong spatial structure for all variables. Shorter spatial autocorrelation ranges of soil nitrogen (1.6–3.5 m) and site characteristic variables (2.6–6.0 m) were detected at the burned site, indicating higher heterogeneity. The spatial scale of soil NH4+ was congruent with those of herb, shrub and regeneration tree seedling cover, indicating local coupling, while that of soil NO3− was not. The number of correlations between soil nitrogen and site characteristic variables in the burned site was greater than in the control. These results indicate that fire could not only create higher heterogeneity patches of soil resources, but also strengthen the local coupling between soil resources and understory vegetation, which may impact the establishment and growth of new individual plants.

]]> Jianjian Kong et al. FRAILTY IN PATIENTS UNDERGOING LEFT VENTRICULAR ASSIST DEVICE IMPLANTATION https://uknowledge.uky.edu/nursing_etds/47 https://uknowledge.uky.edu/nursing_etds/47 Tue, 17 Sep 2019 05:11:30 PDT Heart failure is a progressive condition that affects over 5.7 million Americans and costs associated with heart failure account for 2-3 % of the national health care budget. The high rates of morbidity and mortality along with increased costs from readmissions associated with advanced heart failure have led to the exploration of advanced treatments such as left ventricular assist devices (LVADs). LVADS have demonstrated morbidity and mortality benefit but cost remains extensive with costs per quality-adjusted years > $400,000. With this in mind, it is important to identify those who are most likely to benefit from an LVAD to avoid unfavorable outcomes and cost. Although general guidelines and criteria for patient eligibility have been established, choosing patients for LVAD implantation remains challenging. A new focus on patient selection involves the presence of frailty. While frailty has been studied in the elderly population and in patients undergoing cardiac surgery, frailty in patients undergoing left ventricular assist device (LVAD) remains controversial. The purpose of this dissertation was to examine measures of frailty in patients undergoing LVAD implantation. The specific aims of this dissertation were to: (1) identify a feasible frailty measure in adults with end-stage heart failure who underwent LVAD implantation by testing the hypothesis that frailty would predict 30 day rehospitalization rates using Fried’s criteria, Short Physical Performance Battery test, handgrip strength, serum albumin and six minute walk test (2) Determine whether frailty measures improve 3 months post LVAD implantation (3) compare sensitivity of these three measures to change in frailty.

Surgical approaches, including heart transplantation and LVAD implantation, for patients with end-stage heart failure was discussed in this dissertation. Data from two subsets of participants who underwent LVADS at the University of Kentucky between 2014 and 2017 were included in the analysis for this dissertation. In the first study, we found that none of the measures are good predictors of frailty in patients with advanced heart failure who undergo LVAD implantation. Handgrip was the only marker of frailty that predicted 30 day readmission but the relationship was a negative association. In the second study, six-minute walk and low serum albumin levels reflect short-term improvement in frailty. These simple measures may be used to determine those patients who are responsive to LVAD implantation.

The findings of these studies filled some gaps in our understanding of markers of frailty in patients undergoing LVADs. We gained a better understanding of which markers of frailty are likely to improve in most people after LVAD implantation and thus frailty should not preclude candidate selection for an LVAD. Subsequently, more research is needed to investigate these markers and outcomes.

]]> Candice Falls FUNCTIONAL ANALYSES OF THE DNA- AND RNA-BINDING PROTEIN SPOVG IN <em>BORRELIA BURGDORFERI</em> https://uknowledge.uky.edu/microbio_etds/21 https://uknowledge.uky.edu/microbio_etds/21 Tue, 17 Sep 2019 04:53:01 PDT Borrelia burgdorferi, the causative agent of Lyme disease, exists in a defined enzootic cycle involving Ixodes scapularis ticks and various vertebrates. Humans can serve as an accidental host, if a tick colonized with B. burgdorferi happens to feed on a human. B. burgdorferi are also accidental pathogens: they do not make toxins, or destroy host tissue by other mechanisms. They merely transmit between vector and host to survive. In order to do this, they must effectively sense their current environment, and appropriately alter cellular processes. Understanding the regulatory mechanisms of how B. burgdorferi manages to do this has been a focus of the Stevenson lab for many years.

Previous work identified SpoVG as a DNA-binding protein. Although a homologue of this protein had been implicated to serve a regulatory role in other bacteria, the Stevenson lab was the first to demonstrate a function for the protein, both for B. burgdorferi and two other bacteria. Studies contained in this body of work aim to provide insight into regulation of SpoVG by B. burgdorferi as well the impact that it has on gene regulation.

By using genetic mutants, we determined that SpoVG is regulated at the levels of transcription and translation in culture by growth rate, temperature, and other regulatory factors. Additionally, we provide evidence that SpoVG regulates its own expression. Numerous genes are under control of SpoVG. Biochemical analyses revealed that SpoVG specifically interacts with DNAs and RNAs associated with genes found to be under its regulatory control. Finally, we provide evidence for SpoVG acting in concert with other known regulatory factors such as other DNA-binding proteins and the cyclic di-nucleotide second messengers cyclic-di-GMP and cyclic-di-AMP.

All together, these studies provide insight into how B. burgdorferi broadly regulates cellular processes during different stages of the enzootic cycle. We hypothesize that SpoVG does this through globally manipulating the three-dimensional structure of the bacterial chromosome, and that exactly how SpoVG acts at any given point will be dependent on the other regulatory factors that are also present in the cell.

]]> Christina R. Savage