Dara Bobb-Semple
Stony Brook University (Stony Brook, NY)

Research Mentors:
Christopher Koenigsmann & Dr. Stanislaus Wong
Department of Chemistry
 
Synthesis & Electrochemical Characterization of Potentially Effective Support Materials for Enhancing the Activity of Platinum Based Core-Shell Catalysts Towards Methanol & Ethanol Elextroxidation
 
In this work, we report on the synthesis and characterization of materials for enhancing the activity of Platinum (Pt) based core‐shell nanostructures toward the methanol and ethanol oxidation reaction. Ruthenium (Ru) nanowires (NWs) were synthesized using an ambient, template‐based methodology, employing the use of a modified double diffusion device. The size dependence of these NWs was studied by varying the template dimensions and the concentration of the reducing agent used. We also prepared metal oxide nanoparticles (NPs) utilizing sol-gel and hydrothermal techniques. An aqueous phase reduction was then utilized to deposit Pt NPs onto the surface of the metal oxide NPs. The asprepared metal and metal oxide hybrid nanostructures were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and x‐ray powder diffraction (XRD).

Larisa Kamga
City College of New York (New York, NY)
 
Research Mentors:
Dr. Jessica C. Seelinger
Department of Molecular & Cellular Pharmacology
 
Characterization of Riboswitch‐based Inducible Gene Regulation Systems in Mycobacteria
 
The ability to control gene expression in Mycobacterium tuberculosis is important to understanding the molecular mechanism of its pathogenesis. While some inducible expression systems exist for gramnegative bacteria, they are not easily transferable to M. tuberculosis. Research on M. tuberculosis would greatly benefit from the availability of tools for gene expression control, such as knockouts or genetic induction. One such tool of interest in this study is a riboswitch‐based inducible gene regulation.
 
S. Topp et al. (2010) previously reported successful modulation of gene expression in Mycobacterium smegmatis and M. tuberculosis using synthetic riboswitches, which contain an aptamer that binds theophylline. The specific advantage of riboswitches is exogenous, dose‐dependent and time‐specific control. In this project, we sought to study the behavior of theophylline riboswitches in response to different mycobacterial promoters and to screen the optimal promoter‐riboswitch system for M. smegmatis and M. tuberculosis. Using assembly PCR, we attempted to synthesize different promoters in combination with a riboswitch and to clone these constructs within plasmids to determine their response to the inducer theophylline by quantifying the expression level of reporter genes. Future works will include troubleshooting the cloning reaction for optimized insertion of the promoter‐riboswitch systems within the plasmids, characterizing the behavior of the systems in M. smegmatis and M. tuberculosis , creating a conditional gene knockout in M. tuberculosis using the riboswitch system, and performing in vivo studies to understand the functions of specific M. tuberculosis genes during latency or M. tuberculosis viability during macrophage infection.
 

Evelyn Ojo
University of Maryland, Baltimore County (Baltimore, MD)
 
Research Mentors:
Dr. Congwu Du
Department of Anesthesiology
 
Effect of cocaine on intracellular potassium concentration
 
Cocaine is an addictive stimulant known to cause significant neurological changes and severe cardiovascular disorders if abused. These symptoms stem from cocaine's ability to block the reuptake of dopamine and norepinephrine. Dopamine controls a number of higher order behavioral and cognitive processes such as movement and emotional responses via its receptors. These receptors are known to suppress ion channels (e.g., potassium channels) in the brain. However, the mechanisms underlying cocaine‐induced ionic changes of cells are not fully understood. The goal of this project is to study the effect of cocaine on intracellular potassium concentration in the cell. The potassium‐sensitive fluorescent dye (PBFI‐AM) was used to label the intracellular potassium ([K+]i). The concentration changes in [K+]i in response to cocaine challenge were monitored by fluorescence microscope and quantified by lab‐developed imaging process methods. Our preliminary results show that the potassium ion concentration in the cells was not significantly changed when cocaine concentrations were 30μM-90μM (Δ[K+]i= +2.5% ± 1.3%), however it decreased (Δ[K+]i = -6.2% ± 1.8%) in response to 120μM-300μM cocaine administration. This study demonstrates that the fluorescence technique has a great potential for monitoring [K+]i changes induced by stimulants such as cocaine, which may provide clinical benefits for pharmacological/physiological abnormalities analysis in the future.

Michael Santana
Lehigh University (Bethlehem, PA)
 
Research Mentors:
Luisa Torres & Dr. Stella Tsirka
Department of Moleculra & Cellular Pharmacology
 
The effect of activated microglia on oligodendrocyte survival and possible applications of nanosized Iron oxide particles for tracking microglia in vivo
 
Microglia are the resident macrophages of the central nervous system (CNS) that recognize and engulf foreign cells, present antigens to T cells and scavenge the CNS looking for damaged cells. After injury, the serine protease tissue plasminogen activator (tPA), accumulates at the injury site and starts a signaling cascade that activates microglia. Activated microglia retract their processes and thicken into an amoeboid shape allowing them to quickly migrate to the site of injury. Microglia activation leads to an upregulation of protease and cytokine production, which may be neurotoxic to oligodendrocytes‐ the cells that produce the protective myelin sheath around neuronal axons. We hypothesize that in the absence of tPA, there will be a decrease in microglia activation and consequentially reduced numbers of apoptotic oligodendrocytes and reduced demyelination after spinal cord injury. To explore this idea, wild‐type and tPA‐deficient mice received a contusion injury followed by perfusion at various time points. Tissue sections were stained using the microglia marker Iba‐1. While microglial activation was diminished in tPA deficient mice compared to wild‐type animals in the earlier time points post‐injury, tPA deficient mice showed increased microglial activation at later time points, consistent with previous data. Whether a decrease in activation correlates with decreased numbers of apoptotic oligodendrocytes will be determined by co‐staining for caspase‐3 and 2',3'‐Cyclic‐nucleotide 3'‐phosphodiesterase (CNP). Microglial activation is also induced by the presence of foreign particles. Cultured microglia were exposed to rombohedral Iron oxide nanoparticles for five days to observe microglia activation, survival and particle engulfment through iba‐1 staining, propidium idodide staining and electron microscopy, respectively. We hope to use nanoparticles to track microglia in vivo using magnetic resonance imagining. The results of this experiment will advance our knowledge on the many practical applications of nanosized iron oxide particles.

 
Sarah Feltham
Ph.D. candidate in Music
 
Graduate School Preparation and Development Instructor

 
Joel R. Jiménez
MSW student in Social Welfare
 
Graduate Assistant and Office Liaison

 
Cindy Leiton
Ph.D. candidate in Molecular and Cellular Pharmacology
 
Graduate School Preparation Instructor

 
Rocio Ng
Ph.D. candidate in Ecology and Evolutiony
 
Research Methods Instructor

 
Christopher Young
Ph.D. candidate in Materials Science
 
Graduate School Preparation and Development Instructor

 
Seemab Yousef
Undergraduate student in Engineering Science
 
Residential Liason