Cellular Regulation: From Cells to Human Health
Natural Transformation: The role of ecsA and ecsB in Bacillus subtilis
Christian Loyo, University of Wisconsin-Madison
Natural transformation is the process of translocating exogenous DNA from the environment into a cell and incorporating it into the genome. As a mode of horizontal gene transfer, this phenomenon impacts human health by catalyzing the spread of antibiotic resistance genes within bacterial populations. The mechanism for transformation is not fully characterized, however several proteins potentially involved in natural transformation have been identified through genetic screens in Bacillus subtilis (B. subtilis). Here we investigate the role of two of these genes, ecsA and ecsB, that encode for an ATP-Binding Cassette (ABC) transporter protein with an unknown substrate. We discovered that when either one of the two genes is knocked out, transformation efficiency of B. subtilis decreases by two orders of magnitude compared to wild type. Therefore, we hypothesize ecsA and ecsB contribute to the mechanism of natural transformation. We compared ecsA and ecsB knockout mutants to the wild type strain using cell growth assays, phenotypic microarrays, and reporter assays. Growth assays revealed a premature lysis of the ecsA and ecsB cells growing in nutrient rich medium. Phenotypic arrays indicated that several pathways associated with cell wall integrity are impacted in mutant strains. Using fluorescence microscopy, we observed a smaller fraction of cells appear to express GFP-ComEA, a protein essential to transformation, leading us to further explore activation of transformation associated genes with additional reporters and flow cytometry. Together our current data suggest the ecsA and ecsB knockout strains exhibit decreased transformation efficiency due to decreased expression of late competence proteins.
Lysine acylations in epigenetic regulation
Mathew Perez-Neut, University of Chicago
Metabolic regulation of histone marks is associated with diverse biological processes through dynamic modulation of chromatin structure and function. Here, we report the identification and characterization of a new histone mark, lysine benzoylation (Kbz). We identify 22 Kbz sites on histones from HepG2 and RAW cells. This histone mark can be stimulated by sodium benzoate (SB), an FDA-approved drug and a widely used chemical food preservative, via generation of benzoyl-CoA. ChIP-seq and RNA-seq analysis demonstrate that histone Kbz marks are associated with gene expression and have physiological relevance distinct from histone acetylation. In addition, we demonstrate that SIRT2, an NAD+-dependent protein deacetylase, removes histone Kbz both in vitro and in vivo. This study reveals a new type of histone mark with potential physiological relevance and identifies possible non-canonical functions of a widely used chemical food preservative.
Regulation of atrial heart rhythm by cheRNAs
Johnathan Hall, University of Chicago
Atrial rhythm in mammals is maintained in part by the regulatory transcription factor, TBX5. We recently identified a set of TBX5-dependent noncoding RNAs in mouse cardiomyocytes. Notably, some of these noncoding RNA loci are nearby coding genes that govern essential heart cell processes like calcium-signalling. Using nuclear fractionation and RNA-sequencing, we confirmed that many of these TBX5-dependent noncoding RNAs are also enriched in the chromatin-fraction of the nucleus. When we previously characterized a small number of chromatin-enriched noncoding RNAs (cheRNAs) in other cell types, we found that they often activate nearby gene transcription. Therefore, we hypothesized that the TBX5-dependent, cheRNAs activate nearby genes required for maintaining heart rhythm. Indeed, we observed a reduction in nearby gene expression upon antisense oligonucleotide knockdown of a TBX5-dependent, cheRNA. We further examined the role of mouse atrial cheRNAs in the response to the hormone, Angiotensin II. We found that Angiotensin II induces the transcription of both cheRNAs and pro-inflammatory genes in mouse cardiomyocytes. Taken together, we have identified disease-relevant, transcription factor-dependent, and regulatory cheRNAs in mouse cardiomyocytes. These cheRNAs may be causal in tuning gene transcription to regulate critical heart functions.
A negative feedback loop of vitamin D import into African American prostate cells and tissues may have implications in hormonal carcinogenesis contributing to prostate cancer disparities.
Jason Garcia, University of Illinois Chicago
Prostate cancer (PCa) is a hormonally driven cancer and is currently the third most common cancer in the US. African American (AA) men are disproportionately at risk for both PCa and vitamin D (vitD) deficiency compared to white men. We found that Megalin, a multi-liganded endocytic membrane receptor encoded by the gene LRP2, is present on prostate epithelium and is regulated by vitD. The presence of megalin suggests that globulin bound hormones from the circulation, including 25D bound to vitamin D binding protein (DBP) and testosterone (T) bound to sex hormone binding globulin (SHBG), are imported into prostate in a regulated manner. Moreover, we found similar relationships between serum and intraprostatic testosterone metabolites, further supporting active megalin; AA men had higher levels of dihydrotestosterone (DHT) in prostate tissue compared to white men. Examination of megalin in vitro in primary human prostate cells and in tissue explants demonstrated that globulin-bound hormones are imported into the prostate and transcriptionally active. In vitro 25D deficiency increased expression of megalin protein and LRP2 expression in cells and tissue slices. 25D decreased LRP2 promoter activity in prostate cells. We also observed megalin-mediated internalization of DBP-bound 25D and SHBG-bound T into prostate cells. In summary our findings support the presence of a negative feedback loop in which vitD deficiency increases hormone import into prostate epithelium via Megalin. Therefore the upregulation of megalin in the setting of vitamin D deficiency may facilitate increased import of circulating sex steroids into the prostate contributing to carcinogenesis in AA men.
Seeing the Unseen through Structures and Computation
Laser microdissection of human calcium oxalate monohydrate stones enables structurally specific exploration of the stone proteome
Victor Hugo, Indiana University School of Medicine
Urolithiasis affects approximately 12% of the world population, and more than half of affected individuals will have recurrence within 10 years of the first episode. A detailed hypothesis of the mechanisms of stone disease etiology remains elusive and thus makes stone disease difficult to treat and to prevent. The present study assessed the feasibility of histologically sectioning human stones and using laser microdissection (LMD) to obtain samples for proteomic analysis. Stones were imaged by micro-Computed Tomography, demineralized, embedded in paraffin, histologically sectioned and stained. Regions of the stone-matrix layers were dissected via LMD (Leica LMD 6). Histological sections of stones showed tightly packed layers of matrix that were clearly visible using bright field LMD microscopy. The average area dissected by LMD for proteomic analysis was 1.64×106 µm2, and these revealed and yielded an average of 629 distinct proteins. Initial analysis shows proteins to be similar to those previously reported for kidney stones, including proteins involved in cell injury and repair as well as important mediators of the immune system. Utilization and optimizing of these novel methods and techniques will pave the way into a deeper understanding of stone genesis. Future investigation of the stone matrix proteome should provide insight into the mechanisms underlying the pathogenesis of urolithiasis in an effort to develop effective therapies and prevention treatments.
Spectroscopic and structural characterization of Cysteamine Dioxygenase
Rebecca Fernandez, University of Wisconsin-Madison
The geometric and electronic structure of a non-heme FeII-dependent thiol dioxygenase, cysteamine dioxygenase (ADO), is being investigated using a combined spectroscopic and computational approach. The spectroscopic techniques employed, including electronic absorption, magnetic circular dichroism, and electron paramagnetic resonance, are selective for the different metal ion oxidation states and sensitive to changes in the coordination environment of the iron center. Cysteine dioxygenase (CDO), a well-characterized second mammalian thiol dioxygenase, contains a 3-histidine (3-His) coordination environment rather than the 2-His-1-carboxylate facial triad seen in most mononuclear non-heme FeII enzymes. Similarly, a bacterial thiol dioxygenase, 3-mercaptopropionate dioxygenase (MDO), also contains a 3-His active site that turns over 3-mercaptopropionate (3MPA) into 3-sulfinopropionic acid as part of the sulfur metabolism pathway. In the case of ADO, very little is currently known about the active site environment, though a 3-His facial triad has been implicated on the basis of previous site-directed mutagenesis studies.
Our spectroscopic results provide more direct evidence that ADO indeed also features a 3-His facial triad, like CDO and MDO. Despite this similar coordination environment, our spectroscopic results obtained for ADO incubated with various substrate (analogues) are distinctly different from those obtained for the other FeII-dependent thiol dioxygenases. This finding, in conjunction with our computationally generated active site model, suggest that the secondary coordination sphere of ADO is distinct from that of CDO, demonstrating the significant role that secondary sphere residues play in dictating substrate specificity.
SERS detection of mycotoxins via substrates with linear polymer affinity agents
Rebeca Rodriguez, University of Minnesota
There are a variety of small molecule toxins found in crops that can be extremely carcinogenic to humans, posing dangerous hazards in food production and consumption. This work exploits commercially available polymers as capture agents for various toxin targets such as mycotoxins. Mycotoxins are small molecule toxins produced from fungi, that contaminate crops such as corn and wheat. Detecting mycotoxins traditionally employs the use of specific affinity agents. However, those detection methods are expensive and lack a universal sensing technique to detect a multitude of toxins in complex food matrices. For this reason, we propose the use of a less specific affinity agent, like a linear polymer, to detect these molecules. The capture agents can be immobilized on plasmonic substrates known as FONs, or film over nanospheres, based on their end group reactivity whilst maintaining an affinity for a target. These FONs with short, anchored polymer chains serve as a novel sensing system when paired with surface-enhanced Raman spectroscopy (SERS). SERS is an attractive analytical technique due to its high enhancement factors and its ability to assign specific vibrational modes to certain molecules at very low concentrations. By providing fingerprint spectra for various targets, one can easily detect the target mycotoxins in relevant complex matrices. While investigating varying polymer chain lengths, anchoring chemistries, attachment schemes, and toxins, this work demonstrates optimization of SERS sensing to achieve limits of detection comparable to current detection methods with a simpler and more flexible signal transduction mechanism.
Asymmetry and complementarity in quantum information and
Nicholas LaRacuente, University of Illinois at Urbana-Champaign
Analogy is at the heart of scientific modeling, tracing back as far as Rosenblueth and Wiener’s “The Role of Models in Science (1945).” Usually we replace a complex natural system by a much smaller likeness, such as an equation, simulation or even a simpler physical system. The model predicts essential aspects without the burden of replicating every physical detail. Modeling by material analogs has gained attention in quantum information. The capability of one quantum system to simulate another suggests a potentially near-term form of quantum computing with practical applications in molecular physics and chemistry. We show how the principle of modeling by analogy connects to more recent information-theoretic themes in machine learning and dimensionality reduction. In quantum mechanics, however, the principles of quantum complementarity and measurement disturbance may lock away information needed to parameterize a model. In particular, we consider challenges in Hamiltonian simulation, quantum decoherence and information scrambling. We explain a natural duality between quantum decoherence and the criteria for which a complete but scrambled picture of that system may exist in its environment. We examine the new intuition required by quantum systems, show how we may better approximate some with classical randomness, and consider what this tells us about modeling and analogy in classical stochastic systems.
How the Brain Thinks: Neuronal Activation and Regulation
Functional Impact of Diverse Sodium Currents on Spike Timing Regularity in the Peripheral Vestibular System
Selina Baeza Loya, University of Chicago
An issue in neural coding is the impact of diverse ionic currents on the transmission of sensory stimuli information by neurons. The vestibular system transmits sensory information with two populations of vestibular afferent neurons (VAN), which differ in the regularity of timing of action potentials (AP). The two kinds of AP timing are specialized for different encoding strategies (temporal and rate) which are optimized for different kinds of sensory information. We ask how the two sensory encoding methods arise from differences in the voltage-dependent sodium (NaV) currents that initiate APs. Recent work from our lab indicated expression of all Na channel proteins in VAN, which differ in key properties affecting their voltage dependence and time course, and may carry currents of different modes (i.e., transient, persistent, resurgent). I seek to determine how diverse NaV currents influence the shape and timing of APs. Using whole-cell patch-clamp recordings, I discovered that some neurons expressed persistent NaV current elicited with slow voltage ramps and that other neurons express resurgent NaV current. I hypothesize that these non-inactivating modes repolarize VAN after each spike, promoting the sustained firing that distinguishes the VAN population that fires with regular timing. My long-term goal is to explain how biophysical properties have evolved to analyze sensory stimuli into key features.
Effects of Dopaminergic Fiber Modulation in Bergmann Glia Cells
Nash Vador, University of Alabama Birmingham
Rett Syndrome (RTT) is a neurological, autism spectrum disorder characterized by dyspraxic gait, stereotypic hand movements and dystonia. As RTT commonly involves motor coordination issues, dysfunction in the cerebellum may cause these abnormalities. Due to the role of dopamine receptors in movement, we hypothesize that malfunctioning dopaminergic signaling is responsible for the lack of motor coordination and control in RTT. Notably, there has been limited data on dopaminergic pathway inputs to the cerebellum. Our lab has learned that dopamine receptor 1 (D1) is distributed mainly on Bergmann glial cells (BGs) as opposed to the cerebellums only neuronal output: Purkinje cells (PCs). We aim to investigate dopamine fibers from the substantia nigra pars compacta (SNc) and/or locus coeruleus (LC), and if they indirectly influence PCs by regulating BGs. By using immunohistochemistry in brain sections, we determined that dopaminergic fibers from the SNc extend to the cerebellum. Through single-molecule fluorescence in situ hybridization (smFISH), we learned that D1 receptors are located in BGs as opposed to PCs (which indicated that PCs are indirectly modulated). AMPA receptors have increased levels of BGs and PCs – as dopamine is an important regulator for the system. Therefore, western immunoblot was performed to discern the levels of protein of the glutamate AMPA receptor subunits. Future studies involve removal of D1 receptors in the cerebellum of RTT mice, specifically removal of D1 in BGCs, to study the effects on behavior and motor function.
Analyses in Public Health
Longitudinal analysis of alcohol use and its relationship with Human Papilloma Virus (HPV) and sexual activity among a cohort of undergraduates at the University of Michigan
Eliyas Asfaw, Univeristy of Michigan Ann Arbor
Objectives: Human Papilloma Virus (HPV) is a virus that causes 5% of all chronic diseases especially its oncogenic types (namely type 16). The objective of this longitudinal analysis is to access any synergic relationship between alcohol use and HPV along with the sexual activities of participants in the Michigan HPV and Oropharyngeal Cancer Study across three years.
Methods: The Michigan HPV and Oropharyngeal Cancer Study (M-HOC Study) is a cohort study designed to understand the longitudinal patterns of incidence and prevalence of HPV infections along with its clearance and its association with Oropharyngeal Cancer. The study has more than 400 participants, and about 240 are undergraduate students at the University of Michigan Ann-Arbor. This study consists of a detailed medical and sexual history questionnaire, saliva, and cervical samples. From saliva and cervical samples, HPV was detected using PCR-Mass array method.
Results: Study participants who drank more than 6-9 drinks per week in significantly riskier sexual behaviors than students who did not drink alcohol, especially among women. Also, the volume of alcohol consumption has steadily increased across study visits. Oral sex is the more commonly practiced form of sex (92.8%). In addition, HPV status had a significant association with the level of alcohol consumption, especially at higher levels.
Conclusion: The analysis results show that a high intake of alcohol is heavily correlated with increased sexual activity and HPV infection. Further studies are needed to understand the relationship HPV mechanism and alcohol levels along with tumor suppressors commonly targeted by HPV like p53 and Rb.
The relationship between mental health and maternal adiposity and gestational weight gain in pregnancy
Zainab Shah, University of Illinois at Chicago
Maternal health, both physiological and psychological, can have lasting effects on the mother and offspring. Approximately 10-20% of women experience mental illness during pregnancy or during the first 12 months postpartum. Depression or anxiety during and immediately after pregnancy confers significant risks to both mother and child, including immediate risks of low birth weight and preterm birth, and subsequent risks of stunted growth, altered stress response, poor temperament, compromised mother/child interactions, and externalizing disorders. This study focuses on the interaction between perinatal maternal adiposity and the development of depression or anxiety during pregnancy or the post-partum period. Mental health data was collected from 300 pregnant women from a minority cohort served here at the University of Illinois Hospital and Health Sciences System (UIHHSS). The purpose of this study is to fill the gap of knowledge regarding the extent to which maternal depression and anxiety and maternal weight trends (i.e., pre-pregnancy body mass index (BMI), incident BMI, and gestational weight gain (GWG)) are associated during early and late pregnancy. We hypothesize that higher pre-pregnancy BMI will be associated with increased depression and anxiety in pregnancy, and that women with too little or too much GWG will similarly have higher prevalence of depression and anxiety in pregnancy. Understanding the interaction between maternal adiposity and mental health can broaden the understanding of inter-conception weight changes and emphasize the importance of communication between physicians and patients regarding gestational weight gain during pregnancy as well as preventive measures/interventions to ensure a healthy pregnancy.
1) BMI Percentile, Time in Physical Education Class, Objectively-Based Physical Activity & Sedentary Time during School Hours among Children in Puerto Rico
Maria Enid Santiago Rodriguez, University of Illinois at Chicago
To test relationships between BMI%, physical education time (PET), moderate-vigorous physical activity (MVPA), and sedentary time (ST). 68 girls and 63 boys wore GT3X+ accelerometer to determine MVPA and ST. PET was provided by the school’s administration. Weight and height were used to calculate BMI%. Bivariate correlations, and multiple regression analyses tested relationships between BMI%, MVPA, and ST controlling for wear-time. Univariate ANOVA tested the differences in BMI% by PET. Children (BMI% = 63.0 ± 30.7%) spent 103.9 ± 33.2 min/wk in PET, 110.9 ± 21.8 min/dy in MVPA, and 3.5 ± 0.5 hr/dy in ST. Bivariate correlations revealed significant relationships between BMI% and MVPA (r(101) = 0.24, p=0.01) and ST (r(101) = -0.21, p=0.02).
2) A novel two-component signaling system (TCS) SasY/Z and regulon that contributes to stress resistance and virulence of the bacterial pathogen Listeria monocytogenes
Xiomarie Alejandro-Navarreto, University of Illinois at Chicago
Listeria monocytogenes (Lm) is a relevant public health problem because the bacterium causes multiple outbreaks worldwide as well as recalls due to food contamination in the food-processing environment (FPE). Here we identify a novel two component signaling system (TCS) SasY/Z, that regulates the expression of the virulence chaperones PrsA1, PrsA2, and HtrA as well as several other gene products. Experimental evidence indicates that each gene within the regulon is required for multiple stress conditions, suggesting gene product-specific functions. SasY/Z signaling system thus appears important for the regulation of multiple gene products that contribute to multiple facets of Lm stress resistance both inside and outside of the infected host.
3) Epidemiology of mucopolysaccaridoses
Hira Peracha, University of Delaware
The aim of this study was to obtain data about the epidemiology of the different types of mucopolysaccharidoses in Japan and Switzerland and to compare with similar data from other countries. Data for Japan was collected between 1982 and 2009, and 467 cases with MPS were identified. The combined birth prevalence was 1.53 per 100,000 live births. The highest birth prevalence was 0.84 for MPS II, accounting for 55% of all MPS. MPS I, III, and IV accounted for 15, 16, and 10%, respectively. MPS VI and VII were more rare and accounted for 1.7 and 1.3%, respectively. The high birth prevalence of MPS II in Japan was comparable to that seen in other East Asian countries where this MPS accounted for approximately 50% of all forms of MPS. Birth prevalence was also similar in some European countries (Germany, Northern Ireland, Portugal and the Netherlands) although the prevalence of other forms of MPS is also reported to be higher in these countries. Birth prevalence of MPS II in Switzerland and other European countries is comparatively lower. The birth prevalence of MPS III and IV in Switzerland is higher than in Japan but comparable to that in most other European countries. Moreover, the birth prevalence of MPS VI and VII was very low in both, Switzerland and Japan. Overall, the frequency of MPS varies for each population due to differences in ethnic backgrounds and/or founder effects that affect the birth prevalence of each type of MPS, as seen for other rare genetic diseases. Methods for identification of MPS patients are not uniform across all countries, and consequently, if patients are not identified, recorded prevalence rates will be aberrantly low.
4) Exploring phage structure from head to tail with CryoEM + CryoVR: Virtual Reality Tools for EM training
Brenda Gonzalez, Purdue University
Have you ever wondered what the smallest thing we can detect with a microscope is? With the electron microscope (EM), we can visualize objects nearly 85,000 times smaller than a grain of table salt. This powerful technology allows us to investigate biological samples, such as viruses. I use image processing techniques to convert 2D images of viruses taken on the microscope into high resolution 3D models. These models give us details about the structure down to almost atomic level!
In addition to my work in the lab, I am part of the Purdue CryoVR team. In collaboration with the Computer Graphics Department, PI4D, and the College of Education, I am creating Virtual Reality training tools for cryo-EM. This project is the first of its kind, and the process has been full of new and exciting experiences.
5) Constructing a User Interface for the Alignment of CAT Gratings
Paula Moraga Baez, Northern Illinois University
The objective of this project is to integrate existing software programs into a single software interface that will allow a user to align Arcus critical angle transmission (CAT) gratings before they are bonded to their frames, making grating facets. CAT gratings allow x-ray photons to pass through at an angle that matches the grazing incidence angle, hence the name critical angle transmission gratings. Arcus, an x-ray spectrometer, will require 704 aligned grating facets. Because these gratings are produced with a small amount of error, they must be aligned in 6 axes (translation and rotation) before they are bonded to a facet frame. This is done so that any two of the resulting grating facets can be interchangeable with each other. The current process used to align these gratings requires two people to exchange
measurements and to manually input corrections to alignment: one to control the movement of the Hexapod, a six-legged stage on which the grating will be placed, and the other to perform the data analysis used to calculate the required adjustments. This is impractical for the large scale operation that will be required for the flight-build, causing a need for a simplified alignment process that is completely and comprehensively planned out and that eliminates the possibility of operator error. This project focuses on rewriting existing C# and Matlab programs used to record alignment data and incorporating software for Hexapod movement, as well as demonstrating when alignment has been achieved. The code written in Python will take data, indicate which Hexapod axes to move to achieve alignment and determine that the misalignment has been completely removed.
This work was supported through the NSF-REU Solar Physics program at SAO, grant number AGS-
6) Chemical Communication of a Natural Cheese Rind Fungus with P. psychrophila versus E. coli
Itzel Lizama-Chamu, University of Illinois at Chicago
Previous studies have shown that cheese rinds represent a simplified model of a microbiome that can be experimentally manipulated and reproduced to elucidate pair-wise and community interactions of microbial species. Since the specialized metabolites that drive microbial interactions within these communities are poorly understood, we examined how a cheese fungus altered its specialized metabolites in the presence of either a natural cheese rind bacterium or a pathogen using techniques in mass spectrometry.
Initial phenotypic screening revealed that a pair of naturally co-occurring fungus, Penicillium sp. #12, and bacterium Pseudomonas psychrophila sp. JB418 were found to grow commensally. However, replacing P. psychrophila with Escherichia coli, a foodborne pathogen, elicited an inhibitory response from Penicillium sp. #12 against E. coli. Therefore, we hypothesize that Penicillium sp. #12 excretes metabolites that interact with bacterial partners that produce different phenotypes in P. psychrophila and E. coli. Matrix-assisted laser desorption/ionization time-of-flight imaging mass spectrometry (MALDI-TOF IMS) was used to visualize the spatial distribution of the molecules produced in both pure bacterial and fungal cultures to quickly detect molecules involved in microbial interactions. Molecules produced in each interaction were extracted from a large-scale culture and analyzed via liquid-chromatography tandem mass spectrometry to obtain molecular fragmentation data. IMS data was used to prioritize signals for future isolation and purification using high-performance liquid chromatography to identify the molecule(s) responsible for different phenotypic expression. A long-term future direction of this research will help us to understand the impact the cheese microbiome may have on human health via dietary intake.
7) Individual Differences in Facial Emotion Recognition in Psychosis Risk
Leslie Zuniga, University of Illinois at Chicago
Individuals with schizophrenia demonstrate impaired emotion recognition that is associated with low social functioning. Currently, there is limited research focusing on emotion recognition in individuals who are at high clinical risk for psychosis (CHR). This study examines the effect of individual differences on the performance of a facial-emotion processing task in CHR individuals. We hypothesize that CHR subjects will demonstrate reduced accuracy recognizing negative emotions compared to positive. In addition, that individual differences on gender, age, iq and symptoms may be related to differential performance on the task. 59 individuals (33 males, 26 females) who met criteria performed a facial emotion recognition task using morphed faces. T-tests, correlation and regression analyses were used to assess the effects of differences on task performance. Subjects were also rated on a number of CHR symptoms following a clinical interview. Repeated measures ANOVA shows differences in accuracy depending on the emotion expressed (F=29.48, p<.001) and CHR individuals are more accurate on positive than negative emotions (t=-9.91, p<.001). While there were no overall effects of gender, age, education, or iq, females with higher iq tend to show greater total accuracy (r=.38, p=.06). These results suggest that while CHR individuals show differing performance based on the type of emotion, performance differences cannot be attributed to basic demographic differences or symptom levels. Individuals may need to account for differential effects of emotion type as well as of IQ by gender. Further research is necessary to better understand the differences that impact emotion recognition performance in CHR individuals.
8) Elucidating the Binding of a-Synuclein as a Curvature Sensing Protein
Alessandra Leong, University of Chicago
a-Synuclein (a-Syn) has been implicated in many neurodegenerative disorders, most notably Parkinson’s Disease. Despite the abundance of a-Syn present within the presynaptic terminal and its localization around synaptic vesicles, a great deal remains unknown about its physiological and pathological function. Here, we created a robust model system to accurately probe the binding of a-Syn to lipid membranes as a function of physiological compositions and curvatures. We developed a technique to construct monodisperse spherical-nanoparticle supported lipid bilayers (SSLBs) that act as biologically relevant mimics of the highly curved synaptic vesicles. Confirmed by cryo-electron microscopy, our novel technique for SSLB formation via osmotic stress allows for precise and rigorous experimental control. Using isothermal titration calorimetry, we extrapolate thermodynamic parameters to investigate the binding affinity of a-Syn as a function of electrostatics and membrane surface defects modulated by lipid composition and SSLB curvature, respectively. We find significantly stronger binding affinities (Kd < 1 µM) to SSLBs with higher anionic lipid content and increased curvatures, suggesting that a-Syn is a curvature probing protein. By understanding the precise parameters that control a-Syn binding to biological membranes, we hope to deduce the physiological function of a-Syn and its transition to the diseased states.
9) Synthesis of novel hexanuclear rhenium selenide clusters containing alkynyl ligands
Ernesto Soto, Illinois State University
The Szczepura research group is interested in developing the organometallic chemistry of hexanuclear cluster complexes. Towards this end, we prepared the first rhenium selenide cluster complex to contain an alkynyl ligand, i.e., [Re6Se8(PEt3)5(C=CPh)]+. This presentation will discuss the synthesis and characterization of this cluster complex as well as our progress towards the synthesis of the bis(alkynyl) complexes, cis- and trans-[Re6Se8(PEt3)4(C=CPh)2]. In addition, we will discuss the reactivity of the newly prepared species with various electrophilic reagents. Our studies are aimed at developing the fundamental chemistry of octahedral cluster complexes. Characterization techniques utilized were elemental analysis, mass spectrometry, fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy.
10) What Financial Resources Are Available for Latina Breast Cancer Patients?: Healthcare Personnel’s Perspective
Jocelyne Lemus, University of Illinois at Chicago
Background: Little is known how existing financial assistance programs address these unique needs and Latinas’ awareness of them. To address this gap, we conducted 10 semi-structured interviews with healthcare professionals to understand: 1) Latina patients’ unique economic needs; 2) availability of financial programs to address these needs; and, 3) Latinas’ awareness of these programs.
Methods: Staff from ALAS-Wings and the University of Illinois at Chicago used purposive sampling strategies to recruit 10 healthcare personnel familiar with financial aspects of cancer care for 60-minute semi-structured interviews.
Results: In terms of costs, healthcare professionals perceived that Latinas specifically struggled with non-medical costs (e.g., transportation, living utilities), for which there was economic support from a few foundations (Pink Fund, Patient Advocate Foundation, American Cancer Society). However, healthcare professionals did not believe Latinas were aware of financial programs due to shame/embarrassment and language barriers. Healthcare professionals perceived that these barriers and the prioritization of surviving resulted in delays in seeking financial supports.
Discussion: Our findings highlight the importance of healthcare professionals that are able to explain the availability of resources to Latina breast cancer patients in linguistically and culturally astute strategies immediately following diagnosis and throughout treatment. This resources will help increase Latinas’ awareness and utilization of resources for non-medical and other costs.
11) Tropical land use change effects on the soil microorganism: A meta-analysis.
Emily Diaz-Vallejo, University of Wisconsin – Madison
Globally, tropical regions are being impacted by fast rates of land change due to human deforestation for agriculture and grazing. Land used for agriculture and grazing is affecting soil microorganisms through the shift on plant communities and soil properties. Changes in microbial community composition, abundances and traits can impact multiple ecosystem processes, such as decomposition, nutrient availability and organic matter transformation in soils. However, our understanding of tropical soil microorganism is limited compares to temperate regions. Understanding how land use affects microorganism community composition, abundance, and traits would help us improve management practices, and better understand ecosystem productivity and disturbances. In this project, I synthesized and analyzed soil microorganism traits response to land changes in tropical ecosystems. I identified 102 paired studies and calculated the respond ratio for land conversions of Forests to Pastures, Forests to Croplands, Forests to Plantations and Forests to Secondary forests. I found that microbial carbon and nitrogen biomass are less in croplands, plantations, and secondary forest compared to primary or reference forests. Losses in microbial biomass might reflect management practices that increase organic matter inputs in agriculture and pastures. The results from this review and meta-analysis explain how land change affect soil microorganisms and their contribution to soil processes in tropical ecosystems.
12) Variable effects of long-term nitrogen fertilization on soil carbon cycling in two tropical forests
Elliot Vaughan, University of Wisconsin – Madison
Human alteration of the global nitrogen (N) cycle is widespread and increasing, with the potential to alter ecosystem functioning and biogeochemical cycles. The effects of N enrichment differ by ecosystem, and likely depend on background N availability. Previous studies have shown effects of N enrichment on soil organic matter (SOM) dynamics, although responses are not consistent. Our study uses a long-term (15 year) N fertilization experiment in two Puerto Rican forests to test the effect of N enrichment on SOM cycling. The two forests are from different elevations in the Luquillo Long-Term Ecological Research Site and differ in background soil N content. We show data from soils collected following 15 years of fertilization to measure changes through time in both bulk soil and three SOM pools separated using density fractionation. Fertilized plots showed different trends in the two forests. Fertilized plots had greater bulk soil C in the relatively low-N, upper elevation forest, but showed no difference in the lower elevation forest. There has not been a significant change in soil C content since the last sampling in either forest. Radiocarbon values of the mineral-associated OM fraction show variable trends with fertilization. This research contributes to our understanding of how long-term N enrichment affects soil C dynamics across a gradient of tropical forest soils with different nutrient availability and allow for better prediction of the ecosystem consequences of present and future increases in N availability.
13) Lippia origanoides extract significantly decreases the viability of MDA-MB-231 triple negative breast cancer cells by inhibiting metabolic pathways
Rodrigo Ferreira, Purdue University
Breast cancer is the most common type of cancer worldwide in women, affecting about 1 in 8 females in the U.S. The most aggressive subtype of breast cancer, triple negative breast cancer (TNBC), is typically resistant to conventional therapies that target hormone receptors. Previous studies have shown that a natural extract from Lippia origanoides possesses significant anti-cancer properties. In this study we confirm the concentration-dependent decrease in viability of MDA-MB-231 cells treated with L42, as well as a significant increase in cleaved caspase 8 in MDA-MB-231 cells treated with L42, demonstrating the activation of the extrinsic pathway of apoptosis, and thereby explaining the decrease in cell viability. We also show that the main metabolic pathways were being targeted by the extract. In this study we provide evidences that L42 is a potential source of bioactive compounds that could be used for alternative treatment for TNBC.
14) Hurricane Effects on Soil Properties
Alexander Roman, University of Wisconsin – Madison
With their combination of strong winds and heavy rainfall, hurricanes have the ability to affect ecosystem and soil properties. For example, flooding, mudslides, loss of soil minerals, and changes to plant and animal communities can change soil carbon levels and pH. For this study, Oxisol soils were collected in Cayey, Puerto Rico a month before Hurricane Maria and several collections were taken during the months after it. I will be presenting data on soil pH and soil carbon from Puerto Rico soils before and after Hurricane Maria. Climate change is projected to increase hurricane frequency in the near future, making it important for us to understand how these storms may affect soil.
15) The Influence of Hurricane Maria on Tropical Soil Properties and Soil Carbon Dynamics
Lily Weglarek, University of Wisconsin – Madison
Hurricanes are powerful and can strongly influence ecosystem processes. With the frequency and intensity of hurricanes increasing, the purpose of our research is to better understand how tropical soil properties change as a result of hurricane occurrences. Specifically, we are addressing how Puerto Rican soil organic carbon (SOC) and nitrogen levels vary before and after Hurricane Maria. To determine the hurricane’s effect, soil samples were collected before and after Hurricane Maria hit Puerto Rico. Soils were collected from sites representing forests of three ages and pastures, at three time intervals before and after the hurricane. Our analyses will help to determine the short-term effect of Hurricane Maria on SOC and nitrogen storage in different land coverage types and may provide insight on the effect of hurricanes on soil fertility and climate change.
16) Defining the Role of Transcription Factors in Spatial Organization of the Genome at the Nuclear Periphery
Raven Watson, Northwestern University
The organization of chromatin in the nucleus is deliberately and dynamically maintained. Specific orientations correspond to varying outputs for the cell, aiding it in the management of responses to stress, proliferation, and general upkeep. Modifications in transcriptional regulation target certain genes to the nuclear periphery, creating a distinct organization allowing for activated or more robust transcription. Peripheral localization of genes requires the mediation of transcription factors. A genome wide screen of transcription factors in Saccharomyces cerevisiae revealed that a majority of these factors are a primary facilitator of peripheral targeting, namely HSF1, a regulator of the heat shock proteins. Further mutation analysis confirmed the involvement of nuclear pore protein Nup2, as well as other related components. Nup100 dependency was shown by roughly half of the transcription factors screened, demonstrating two different pathways for nuclear localization. In order to establish whether this mechanism of peripheral targeting was evolutionarily conserved, human heat shock factor, HsHSF1, was screened and identified as a facilitator of gene positioning to the nuclear periphery as well. Similar mutation analysis revealed that HsHSF1 required Nup1, Nup2, and Nup100 and may require an additional phosphorylation event. Observing this mechanism in homologs of yeast transcription factors further underscores the significance of the role this active chromatin organization plays in the proper regulation of the eukaryotic genome.
17) Fabrication and Characterization of Nanoelectrodes used in Scanning Electrochemical Microscopy (SECM)
Heriberto Flores, University of Illinois at Urbana-Champaign
Scanning Electrochemical Microscopy (SECM) is an electroanalytical tool implemented to acquire localized measurements and mapping of electrochemical processes occurring at a surface. The methodologies based on SECM provide a range of tools for quantitative analysis of materials related to energy storage and catalysis. SECM is a scanning probe technique which typically utilizes conductive probes on the micrometer and nanometer scale submerged in electrolyte solutions. Significant developments in SECM point to the nanometer sized probes as the preferred instrument over the micrometer sized probes. The benefit of smaller electrodes is the improved resolution for studying nanosized species. However, handling nanoelectrodes is known to be difficult. Tip breakage frequently occurs, and one must execute caution when handling these fragile probes. Here, we focus on different nanoelectrode fabrication methods and their characterization. Through SECM and other electroanalytical methods, we assessed their probe quality for different electroanalytical applications.