Faculty Research Mentors
Research Project Descriptions
Project Description: Understanding synaptic partner choice in C. elegans. Dr. Miri VanHoven’s Research Group. Neural circuit formation and maintenance remain poorly understood. In my lab, we study the molecular mechanisms that mediate these processes using a combination of powerful tools. These include a split-GFP based fluorescent trans-synaptic marker called NLG-1 GRASP (Neuroligin-1 GFP Reconstitution Across Synaptic Partners) that I developed to visualize synapses in live animals; a high-throughput assay of circuit-specific behavior to assess circuit function; and cGMP imaging within neurons. Examples of possible student projects are: (a) generation of transcriptional fluorophore fusions to examine transgenic C. elegans carrying these transgenes and determine the endogenous expression patterns of these cadherins, and (b) generation of cell-specific rescue constructs to determine if mutant animals carrying these transgenes have rescued synaptic number.
Project Description: Understanding oxidative stress and courtship behavior in Drosophila melanogaster. Dr. Rachael French’s Research Group. In my lab, we focus on two major projects: developmental effects of toxic drugs such as ethanol and nicotine on development using the fruit fly Drosophila melanogaster as a model system, courtship behavior in male flies, and the function of the orphan G-protein coupled receptor (GPCR) Tre1 on this behavior. In particular, we are interested in using molecular and genetic techniques to identify the molecular targets as well as characterize the developmental pathways they disrupt. We have found that mutation of Tre1 (or feminization of neurons expressing Tre1) leads to a unique phenotype: rapid courtship initiation. Our current investigations focus on understanding how neurons function to reduce the speed of courtship behavior (when this function appears to be non-adaptive), as well as identification of both the ligand for Tre1, as well as the downstream components of the Tre1-GPCR signal transduction pathway. Examples of possible student projects are: (a) characterization of the effects of mutations disrupting insulin signaling on the feeding behavior of flies reared in ethanol, (b) characterization of the results of altered insulin signaling, (c) characterization of the fates of developing cholinergic neurons in flies developing in nicotine-containing food, as well as ethanol-containing food, (d) screening of candidate ligands to identify the Tre1 ligand important for courtship behavior, and (e) screening downstream components of GPCR signaling pathways (including a variety of Gα, Gβ, and Gγ subunits) to identify the signal transduction pathway downstream of Tre1.
Project Description: Plasticity in the sensory nervous system. Dr. Katie Wilkinson’s Research Group. We use an in vitro mouse model to study the complex muscle spindle sensory organ that provides information about muscle movement and length. Proprioception, or the sense of body position and movement in space, is vital for the completion of complex motor tasks. The most important proprioceptors are thought to be the muscle spindle afferents (MSAs), the Group Ia and II sensory neurons that innervate the muscle spindle. Proprioception and MSA signaling properties can be altered by many conditions, including exercise, although the relative contributions of central and peripheral mechanisms are not well understood. Current experiments are determining whether substances released during exercise and activity alter MSA responsiveness via peripheral mechanisms that do not require the central nervous system. These studies will enhance our understanding of the response properties and regulation of proprioceptors and suggest peripheral mechanisms for activity-dependent plasticity.
Project Description: Evolution of uncultivable Bacteria and Archaea in natural complex microbial communities by type and function. Dr. Cleber Ouverney's Research Group. We are primarily interested in studying the evolution of microbial diversity of the uncultivable Bacteria and Archaea using molecular methods such as genomic DNA extraction, cloning, PCR, ribosomal DNA sequence analysis, phylogeny, and fluorescence in situ hybridization (FISH). We have focused on the Candidate Phylum TM7, found in diverse environments such as seawater, soil, wastewater sludge, volcanic ashes, termite guts, and the human body. Moreover, some TM7 strains form segmented filaments of over 100 microns long that intertwine into clusters and are associated with many bacteria. This suggests TM7 may be involved in the formation of biofilms, known to promote changes in gene expression through quorum sensing. We will also use a technique called Substrate-Tracking Autoradiography and Fluorescent In Situ Hybridization (STARFISH), that combines FISH with autoradiography, and quantitatively measures uptake of single or multiple nutrients by a group-specific bacterium cell within its natural mixed community. Examples of possible student projects are: (a) investigate the diversity of TM7 in situ, using molecular methods, (b) characterize TM7, in those natural environments, through quantitative and qualitative molecular methods, (c) establish the function of uncultivable bacteria in their natural environment through culture-independent methods such as STARFISH, and (d) use environmental TM7 as models to propose mechanisms by which these bacteria affect their microbial communities and potentially their function in biofilm formation.
Project Description: Identify and characterize transcriptional regulators of lanthanide-dependent methanol oxidation. Dr. Elizabeth Skovran’s Research Group. A major focus of my lab is to understand the metabolic and molecular properties that allow for lanthanide-dependent methanol growth in methylotrophic bacteria, and to engineer these bacteria for lanthanide recovery. Many methylotrophic bacteria use lanthanide elements as a cofactor for the XoxF methanol dehydrogenase enzyme. Our lab has shown that Methylobacterium extorquens has can use XoxF to recover lanthanide elements from discarded electronics waste and mining ores suggesting that ecofriendly biomining and biorecycling strategies may be possible. We are currently identifying and characterizing the gene products required for lanthanide-dependent methanol oxidation including those required for lanthanide acquisition and transport, expression of xoxF, and XoxF function. Examples of possible student projects are: (a) employ selections, flow cytometry and cell sorting, and automated robotic replica printing and screening, (b) identify insertion locations by PCR amplification, sequencing and genomic comparison, (c) use traditional cloning approaches to construct mutations, transcriptional or translational reporter fusions or expression constructs, and (d) produce fluorescent transcriptional reporters and monitor gene expression in different strain backgrounds and under different conditions.
Project Description: The role of pHi in development. Dr. Bree Grillo-Hill Research Group. Many studies have focused on the signaling pathways, transcriptional regulation and physical cues that direct development. However, little is understood about the chemical cues that influence development, such as intracellular pH (pHi). My research investigates how pHi regulates morphogenetic cell processes during development. My lab investigates how this fundamental and understudied property of cells can shape and influence tissues using Drosophila genetics, cell biological techniques, and biochemical analysis of proteins using fruit flies at different stages of development. Transient changes in pHi are known to regulate critical cellular processes including proliferation, cell migration and programmed cell death. We have observed pH gradients in developing tissues in flies at distinct developmental stages, and we hypothesize that these transient changes in pHi facilitate important developmental transitions. However, the significance and function of these gradients is completely unknown. Examples of possible student projects are: (a) identification of ion transporters that regulate pHi in developing Drosophila tissue, (b) identification of the functional consequences of disrupting these gradients during development, and (c) identification of the proteins that sense and respond to changes in intracellular pH.
Project Description: Identification of the roles of digestive proteases from Aedes aegypti mosquitos. Dr. Alberto Rascón Research Group. My lab focuses on the molecular cloning and expression of the most abundant Aedes aegypti mosquito midgut proteases. These proteases are essential in digesting blood meal proteins into amino acids and peptides needed to fuel the egg laying process. The lab is interested in understanding the roles of each protease. Our research will advance the understanding of Ae. aegypti midgut proteases by biochemically studying the four most abundant midgut proteases and other recently identified proteases. More importantly, we will use molecular biology techniques to clone the genes of interest, but also perform site-directed mutagenesis to alter important amino acids in the active and binding sites of the enzymes. Examples of possible student projects are: (a) clone mosquito genes into bacterial expression vectors (e.g., pET28a, pET29b, pMAL) to produce native, His6-tagged and maltose binding fusion proteases, (b) perform site-directed mutagenesis of cloned genes, and (c) express recombinant mosquito proteases and perform activity assays.
Project Description: Development of hybrid P450 enzymes. Dr. Lionel Cheruzel Research Group. Our long-term objective is to develop efficient biocatalysts for the selective oxidation of various substrate C-H bonds upon visible light activation. The biocatalysts contain a Ru(II)- diimine photosensitizer covalently attached to P450 BM3 heme domain mutants. Cytochromes P450 are heme-thiolate enzymes that use molecular dioxygen and two reducing equivalents to catalyze the selective oxidation of unactivated C-H bonds in a variety of organic substrates. Our alternative approach relies on taking advantage of the photophysical properties of Ru(II) photosensitizers to deliver the necessary electrons to P450 BM3 heme domains and harvest their synthetic potential upon light irradiation. To date, a small series of hybrid enzymes already developed in the PI’s laboratory is able to perform the light-driven selective hydroxylation of lauric acid. Examples of possible student projects are: (a) alter the P450 structure by site directed mutagenesis, protein expression and purification of mutated proteins, and (b) biophysical characterization of mutated proteins. Students will be using modern equipment such as FPLC and GC/MS apparatus, fluorometer, mass spectrometer and UV-vis spectrophotometer pertinent to their projects.