Podium Session B

ABSTRACT:

The development of Alcohol Use Disorder(AUD) is characterized by synaptic plasticity, including changes in receptor expression, but the specific mechanisms underlying that plasticity are still unclear. Genome-wide association studies of families with multiple alcoholics have shown a common single nucleotide polymorphism in the GABRA2 gene, which codes for the α2 subunit of the GABA_A receptor. Our research looks at changes in the α2 subunit in response to voluntary alcohol exposure. We found that α2 is highly expressed in the nucleus accumbens on cells containing D1 dopamine receptors. Using immunostaining, we found increased α2 expression upon voluntary access to alcohol. Regulation of α2 expression may be required for the development of AUD. In a mouse model with altered α2 expression, we assessed the development of dependence through multiple behavioral assays. In the conditioned place preference task, the mutant mouse model did not develop a preference for the alcohol-paired floor. In a two-bottle choice experiment, given intermittent access to alcohol over a period of 21 days, the mutant mouse model did not develop a preference for alcohol. Our research shows that the α2 subunit of the GABA_A receptor is critical for the development of dependence for alcohol. We are currently investigating the mechanisms that regulate α2 expression. Understanding the mechanisms behind this subunit regulation could lead to more specific therapies for AUD and a better understanding of the development of dependence.

ABSTRACT:

A metabolic by-product of aerobic cell respiration, reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) can lead to oxidative stress when overproduced. Since this can be a contributor to neurodegenerative diseases and age-related cancer, developing detection methods for small quantities of ROS at the cellular level is important. Current methods of detection are mostly spectroscopic and can lack in their selectivity and sensitivity. Additionally, real-time measurements are a challenge. Electrochemical detection, however, offers several advantages including low cost, ease of use, and the potential for real-time measurements. Furthermore, modification of the electrode surface can alter the specificity, giving a more specialized electrode for the target analyte. Boron-doped diamond (BDD) electrodes are excellent substrates for metal nanoparticle (NP) modification because they are inert, robust, and offer smaller capacitive current. In this work, we optimized our 2-step on-electrode NP synthesis method and executed a detailed comparison of platinum (Pt) and palladium (Pd) NPs on BDD. Control experiments on glassy carbon (GC) electrodes were also completed and a combination of chronoamperometry (CA) and cyclic voltammetry (CV) were the electrochemical methods used. The concentration of the Pt and Pd solutions for the 2-step modification was varied in order to find an optimum. Several factors were considered when choosing the highest performing NP-modified electrode(s) including sensitivity, limit of detection (LOD), limit of quantification (LOQ), double layer capacitance (Cdl) and repeatability. An optimum was found with a concentration 0.5 mM Pd in the 2-step modification where a LOD of 3 µM was obtained. This is a 5-fold improvement over the bare BDD electrode and a 2-fold increase over the optimum Pt concentration (1.0 mM). The response on Pd was also repeatable as below a 10% relative standard deviation (%RSD) was obtained. Overall, this work lays the foundation for future experiments in biological media.

ABSTRACT:

Reclaimed water contains macro and micro nutrients required for plant growth but also contain pharmaceuticals, personal care products, industrial chemicals, antibiotic resistant bacteria (ARBs) and antibiotic resistant genes (ARGs). The presence of these contaminants of emerging concerns (CECs) can cause potential human health problems. Therefore, there is a need to address the uptake and transport of these CECs in agriculture sector. This research evaluate the extent CECs associated with reclaimed irrigation water are taken up by tomato plants and assess if differences in uptake occur in hydroponic vs. oil systems. The initial results from hydroponics experiments for ozonated system show the presence of four contaminants (Sucralose, Triclosan, Sulfamethoxazole and DEET) in tomato roots, two (DEET and Sulfamethoxazole) in stems, six (Sucralose, Sulfamethoxazole, Meprobamate, Lidocaine, DEET and Carbamazepine) and seven (Benzotriazole, Trimethoprim, Triclosan, Sulfamethoxazole, DEET, Carbamazepine and Atenolol) in fruit. The results for ultrafiltration hydroponics system show the presence of five (Bezotriazole, Lidocaine, Sucralose, Sulfamethoxazole, and Triclosan) in roots, five (Carbamazepine, DEET, Lidocaine, Sulfamethoxazole, and Triclosan) in stems, six (Carbamazepine, DEET, Lidocaine, Meprobamate, Sucralose, and Sulfamethoxazole) in leaves and three (DEET, Sulfamethoxazole and Triclosan) in fruit. The results for ozonated hydroponics system for spinach plants show the presence of Sulfamethoxazole in roots, and four (DEET, Lidocaine, Sucralose and Sulfamethoxazole) contaminants in leaves. These results will help us determine the effect of plant species and water treatment on accumulation of CECs in plants.

This research aims to determine the potential human health risks associated with irrigation using reclaimed water and the viability of hydroponics as an alternative agricultural technique for water scarce areas. This research will also assess the potential of advanced pretreatment (i.e., ultrafiltration and ozonation) to mitigate these associated risks. The results will help develop more detailed management practices to ensure food safety for irrigation practices using reclaimed water.

ABSTRACT:

Microglia integrate complex molecular signals to respond against infections in the brain. Metabolic pathways altered in activated microglia are critical for controlling microglial responses. The metabolic diversity of microglia demands high mitochondrial energy that are reflected in depolarizations in the mitochondrial membrane potential (ΔΨm). Disruptions to mitochondrial function have been shown to impact cellular metabolism, apoptosis, and immunity. However, specific functions of mitochondria in glial cells facilitating tissue homeostasis remain unclear. Microglia activation is speculated to be tightly coupled with mitochondrial membrane dynamics and is a potential indicator of the metabolic processes involved in inflammatory states in the brain. In this study depolarization of microglial ΔΨm were explored using acute slices with eGFP labeled microglia dye loaded with tetramethylrhodamine ethyl ester (TMRE). Immunostimulant Lipopolysaccharide (LPS) was bath applied to acute cortical slices and dynamic depolarizations in the ΔΨm of microglia were recorded using timelapse imaging at distinct temporal windows. Depolarizations in the ΔΨm of the surrounding neuropil showed temporal variability, which could suggest differences in the mitochondrial membrane dynamics of each cell type or a distinction in microglial ΔΨm response to an acute dose of LPS. Increased depolarizations from the microglial soma to the endfeet were recorded in the ΔΨm overtime, indicating distinct mitochondrial states. Application of neuroprotective drug, Emapunil, attenuated the depolarization of the ΔΨm at each of the microglia mitochondrial states. Understanding the mitochondrial membrane dynamics that underlie microglia during periods of acute neuroinflammation will open novel avenues for therapeutic modulation of mitochondrial dynamics in gliotic conditions.

ABSTRACT:

Discrete brain areas exhibit local activity patterns with distinct temporal and spatial characteristics. Circuit level perturbations to rhythmic patterns are characteristics of altered arousal states and behaviors. Using pulsed electromagnetic fields, transcranial magnetic stimulation (TMS) alters states of cortical excitability and motor output. Current techniques to understand the mechanism and scope of TMS as a therapeutic are limited by the lack of a robust and focally stimulating murine model. Developing a focally stimulating TMS model in mice is a multivariate problem requiring proper consideration of both circuit design and coil construction. A high voltage, fast switching, insulated-gate bipolar transistor (IGBT) pulse generator delivering large current pulses was developed for the generation of focal electromagnetic fields. To compare the validity of the presented design with current methods, stimulating pulses were delivered to mice using a butterfly coil attached to a standard TMS system compared to a compact coil attached to the novel circuit. Changes in cortical electrical potentials were recorded at two cortical surface electrode sites using electroencephalography (EEG). Butterfly coil stimulation resulted in movement related cortical potentials (MRCPs) at both EEG recording sites while stimulation with the compact coil elicited MRCPs at a single recording site. Furthermore, the compact coil evoked MRCPs similar in amplitude to MRCPs evoked by the butterfly coil. This novel circuit design enables exemplar stimulation of focal and robust MRCPs. The potential for focal stimulation in murine models will provide valuable insight into stimulation of discrete cortical areas affected by disease, like stroke.