PERT Faculty Interests

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Alexander V. Badyaev - Ecology & Evolutionary Biology

Dr. Badyaev's research focus is at the interface of evolutionary developmental biology and evolutionary ecology, with specific focus on the understanding of the origin of adaptations. The unified theme of his work is the construction of evolutionary framework that reconciles phylogenetic conservation of cellular and generative processes with exceptional diversification in morphology, physiology, and behavior of organisms. Under this general umbrella, Badyaev lab studies: 1) origin and evolutionary diversification of pigmentation systems in animals, specifically carotenoid-based colorations, 2) relationship between epigenetic and genetic inheritance systems, and 3) evolution of behavioral and life history strategies.

David Baltrus - Department of Plant Sciences

Research in the Baltrus lab utilizes genetic and genomic approaches to broadly address questions concerning evolutionary and ecological dynamics within microbial populations. Specifically, we are focused on understanding the forces that structure host range within the phytopathogen Pseudomonas syringae on a variety of hosts as well as survival of this bacterium in it's epiphytic niche.

There have been a handful of recent reports that suggest P. syringae can survive, and possibly be vectored across plants, by insect hosts. However, the genetic basis and ecological role of P. syringae that enables interactions with insects (and vice versa) remains completely unclear. Furthermore, these previous reports have demonstrated that phenotypic diversity exists across P. syringae strains for this insect interaction; one strain appears to have no detrimental effect within aphids while a second strain rapidly kills these hosts. Transposon based screens within other labs have failed to identify the genotypic basis of these differences. Understanding the genetic basis of this effect could facilitate the development of better treatments for control of insects such as whiteflies.

We are interested in identifying the evolutionary basis of and genes involved in aphid killing by P. syringae using a combination of comparative genomics coupled with phylogenetically informed strain selection. We are further interested in extending knowledge of the P. syringae/insect relationship to other systems including whiteflies, Drosophila, Manduca, as well as other systems that are available. We have begun to test a diverse group of P.syringae strains (and close relatives) for virulence in aphids and whiteflies, and have shown that entomopathogenicity is a recently evolved trait. Surprisingly, only a handful of strains appear to have this ability, and this fine scale phentoypic diversity should facilitate identification of the underlying genes using comparative genomics. As a different approach to identify genes involved in insect virulence, we have selected for attenuated strains of P. syringae that are no longer able to kill aphids. Genome sequencing of these isolates should provide novel insights into the genes and pathways underlying insect virulence.

Jennifer K. Barton - Biomedical Engineering and Electrical and Computer Engineering

The focus of Dr. Barton's current research is on Optical Coherence Tomography. OCT is a non-destructive imaging technique which uses infrared light to visualize subsurface structure in biological tissues. Depths of a few millimeters can be imaged with about 20 micrometer ( F m) resolution. OCT is analogous to ultrasound imaging, but the magnitude of reflected light is measured instead of reflected sound waves. OCT achieves relatively high resolution and large depth of imaging by combining characteristics of confocal microscopy and white light interferometry. OCT uses a special light source with a short coherence length in a fiber Michelson interferometer arrangement Only light which travels the same distance in both the sample and the reference arms of the interferometer will interfere and be detected. Images of subsurface tissue structure can be built up pixel by pixel, by moving the reference arm mirror and by scanning the sample arm across the tissue. She is specifically working on the technologies of miniature endoscope design and image processing. She is interested in applications of this technology to cancer (skin, colon, and ovarian) and vascular implants.

Judith Bronstein - Department of Ecology & Evolutionary Biology

Dr. Bronstein's lab focuses on the study of interspecific interactions, particularly on the poorly-understood, mutually beneficial ones (mutualisms). Specific conceptual areas of interest include: (i) evolutionary conflicts of interest between mutualists and their consequences for the maintenance of beneficial outcomes in these interactions; and (ii) context-dependent outcomes in both mutualisms and antagonisms. Her primary research systems are the mutualisms between tropical figs and fig wasps, and between yuccas and yucca moths in desert grasslands; in both cases, the insect is simultaneously a host-specific pollinator and a seed predator. Using a combination of field observations and experiments, she is examining how population processes, abiotic conditions, and the community context determine net effects of the interactions for the fitness of each participant.

Heidi Brown - Epidemiology and Biostatistics Division

Heidi E. Brown, PhD, MPH, has a research focus on the epidemiology and control of vector-borne and zoonotic diseases. Her goal is to identify human disease risk by modeling vector, host and pathogen distributions. The complex nature of the systems she works on diseases requires her to blend field collecting, ecological assessment, laboratory experiments, epidemiological analysis, spatial statistics, remote sensing, geographic information systems, and computer-based modeling in order to develop a more comprehensive view of disease dynamics. Current research areas include: West Nile virus, dengue, canine heartworm, valley fever, spatial epidemiology, and climate change.

Judith Brown - Department of Plant Sciences

Dr. Brown's research interests focus on the virology of whitefly-transmitted plant viruses, whitefly-geminivirus interactions which facilitate virus transmission, and whitefly-host interactions that impact on disease spread in monoculture/ weed agroecosystems. Projects include: 1) biological and molecular investigations of previously uncharacterized viruses for the purpose of understanding disease epidemiology, and to identify virus genes for the use in developing engineered resistance strategies, 2) the correlation of virus-vector transmission characteristics with in situ localization of geminiviruses in the whitefly vector, and 3) molecular level investigations of biologically distinct B. tabaci biotypes or populations. The long-range goal is to develop strategies by which plants can be engineered for resistance to virus infection and/or to interfere with virus-vector interactions, which are necessary for whitefly-mediated transmission.

Richard C. Brusca - Center for Sonoran Desert Studies, Arizona Sonora Desert Museum

Dr. Brusca is an evolutionary biologist and invertebrate zoologist with interests in invertebrate systematics, phylogenetics, biogeography, and biodiversity pattern analysis. His principal appointment is Director of Conservation and Science at the Arizona-Sonora Desert Museum where he works with several other specialists on Sonoran Desert natural history. He would like to work with a postdoc interested in developing a research project in the area of insect biodiversity that would dovetail with existing or planned field programs through the Desert Museum. Museum researchers are currently engaged in several projects in northwestern Mexico/southern Arizona that could benefit from an additional entomological component. Some current programs are: (1) Insect biodiversity and land use change in Sonora: biodiversity across natural and anthropogenic landscapes in northwestern Mexico. (2) Tropical corridors linking Mexico and the United States: biotic linkages and trans-border routes in a basin-and-range landscape. Other project ideas integrating insect biodiversity into the research and teaching programs of the ASDM will also be considered, including projects focusing on the two N.W. Mexico Biosphere Reserves (i.e. the El Pinacate/Gran Desierto B.R. and the Upper Gulf of California/Colorado Delta B.R.). The postdoctoral candidate would work at the ASDM, under the supervision of Dr. R.C. Brusca, and be expected to cooperate with existing research and education staff.

Yves Carriere - Department of Entomology

The last fifty years have shown that insect pests have strong potential to evolve resistance to synthetic pesticides and resistant plants produced by traditional methods of selection. One important goal of Dr. Carriere's research is to develop deployment strategies for transgenic plants that maximize durability of resistance. Model systems include a sap-feeding generalist insect, the sweetpotato whitefly, and a specialist lepidoptera, the Pink bollworm. To determine how to build and use transgenic plants for whitefly control, the interaction between different introduced plant and insect genes and whitefly behavior, population dynamics, susceptibility to natural enemies, and rate of evolution of resistance is being investigated.

Goggy Davidowitz - Department of Entomology

Dr. Davidowitz's broad area of interest is in ecological and evolutionary physiology: how organisms adjust growth and fitness in response to environmental variation. Currently, he has three main foci of funded research. 1) Physiology of life history tradeoffs: how does environmental variation affect the priority rules of tradeoffs between flight and reproduction, two traits with high energy demands. 2) Developmental physiology: he studies the physiological mechanisms by which insects translate variation in diet quality and temperature, two environmental factors with strong effects on life histories, into phenotypic and genetic variation in body size and development time, two traits highly correlated with fitness. 3) Plant-insect interactions: how do host quality and humidity gradients affect nectar foraging and fitness in large hawkmoths. Dr. Davidowitz's lab places a strong emphasis on the whole organism and uses a diverse set of tools and disciplines for an integrative approach to these questions.

Katrina Dlugosch - Department of Ecology & Evolutionary Biology

Dr. Dlugosch's research focuses on the genetics of colonization and its evolutionary and ecological outcomes. This work draws largely on the natural experiments provided by human-mediated species introductions and climate-induced range changes. She's working to understand how the genetic variation in founding populations translates into phenotypic diversity, adaptation, and changes in ecology. To get at these questions, members of the lab employ a variety of genetic approaches (quantitative, molecular, and genomic/bioinformatic) as well as field experiments. Projects include studies of the genetic basis of tradeoffs between plant growth and defense against herbivores and pathogens, the genetics basis of inbreeding and heterosis, the sources of variation for rapid evolutionary changes, and the demographic consequences of adaptation.

Anna Dornhaus - Department of Ecology & Evolutionary Biology

Organization in groups, how collective behaviors emerge from the actions and interactions of individuals, is the main interest of Dr. Dornhaus. As model systems she studies social insect colonies (bumble bees, honey bees and ants) in the laboratory and in the field, as well as using mathematical and individual-based modeling approaches. She investigates mechanisms of coordination in foraging, collective decision-making, task allocation and division of labor. Her recent work has included the role of communication in the allocation of foragers to food sources; the evolution of different recruitment systems in different species of bees, and how ecology shapes these recruitment systems; house hunting strategies in ants; speed-accuracy trade offs in decision-making; and whether different group sizes necessitate different organizational strategies.

Andrew J. Fuglevand - Department of Physiology

The broad goal of the work carried out in my lab is to understand how the mammalian nervous system controls the action of skeletal muscles to produce coordinated movements. Our experiments address a range of topics from those related to how individual neurons integrate synaptic information to those associated with the development of new methods to restore movement and sensation in paralyzed individuals. This work has been supported continuously by the National Institutes of Health since 1995. We are currently engaged in the following basic and applied research projects: investigation of the neural and muscular mechanisms that underlie the control of finger movements; characterization of the fundamental properties by which motor neurons integrate synaptic information; studies of the rules governing communication between somatosensory afferents and spinal motor neurons; identification of the neural and muscular factors underlying fatigue; characterization of the patterns of facial muscle activity associated with facial expressions; development of new methods to restore movement in paralyzed limbs using functional electrical stimulation; development of an electrotactile-stimulation system to restore sensation in individuals with spinal cord injuries.

David Galbraith - Department of Plant Sciences

Dr. Galbraith's program focuses on four main areas: Biological Instrumentation, Developmental Plant Gene Expression, Plant Functional Genomics, and Plant-Insect Interactions. His work aims to characterize those plant genes that are responsive to abiotic stress, particularly osmotic and salt stress. His laboratory provides scientific resources to the research community, in the form of EST sequences, insertional mutants, and genomic information.

Wulfila Gronenberg - Department of Neuroscience

Dr. Gronenberg's interests include ecological and evolutionary aspects of neuroethology as well as movement control, muscle function and biomechanics. His interests extended from the periphery to the central brain regions where more complex behavior is generated and controlled.

Martha Hunter - Department of Entomology

Dr. Hunter's research area is biological control and the ecology and evolutionary biology of parasitoids and predators. One aspect of my research involves trying to understand how interspecific interactions influence biological control. The lab is currently studying competition and hyperparasitism in two whitefly parasitoids in order to determine whether these interactions may lead to reduced pest suppression. The parasitoids that are of special interest are autoparasitoids; females develop as primary parasitoids of whiteflies, while males develop as hyperparasitoids, developing either on females of their own species or on other primary parasitoids. The sex-specific host relationships of these animals force one to adopt a different perspective on such topics as sex allocation, host selection behavior and parasitoid-host population dynamics. Dr. Hunter is also interested in the effects of selfish genetic elements such as parthenogenesis-inducing bacteria on the behavior and life history of these parasitoids.

Shanker Karunanithi - Department of Neuroscience

A synapse is a specialized connection facilitating information transfer from a neuron to a target cell by releasing neurotransmitters from synaptic vesicles. Learning and memory formation, stress adaptation, drug addiction and withdrawal, depression, and fear conditioning are examples of behavioral changes reinforced in part by altering the strength of the transmitted signal at individual synapses (synaptic strength). For example, learning and memory formation are correlated with increases in synaptic strength. Intriguingly individual synapses differ in their signaling strengths, and the extent to which their strengths can be modified. Reconciling the diversity in strengths amongst different synapses and their capacity for functional alteration, with changes in behavior remains one of the greatest of challenges. The broad research interests of the laboratory are to elucidate the determinants of synaptic strength under normal and stressful conditions. In particular, to determine the factors generating differences in strengths amongst synapse types, and how synapses functionally adapt to acquire heat-resistance. Drosophila, a model organism whose genome is now sequenced, readily lends itself to genetic, ultrastructural and physiological analysis. Availability of many mutants, and provisions for advanced genetic manipulations are unmatched in any other organism. The readily accessible larval neuromuscular junction preparation which functionally resembles mammalian excitatory glutamatergic synapses will be utilized in our work. The following techniques will be utilized in the laboratory: focal macropatch recording from individual synaptic boutons, intracellular recording, voltage clamping, calcium imaging, UV flash photolysis of caged compounds, serial reconstruction of synapses using electron microscopy, confocal microscopy, immunohistochemistry, DNA microarrays, gel electrophoresis, generation of transgenic Drosophila, RNA interference (RNAi) to silence gene function.

Luciano M. Matzkin - Department of Entomology

Evolutionary and ecological genetics of adaptation and speciation. The lab works to understand how the ecology of a species or population can shape variation at multiple levels, from gene to genomes as well as to the organismal. Additionally, we are interested on how these changes can facilitate the evolution of reproductive incompatibilities and eventually speciation. We examine these questions in the cactophilic Drosophila species system. These species provide a powerful platform, with rich ecological information, genomic tools as well as the ability to perform manipulative experiments.

Bill Montfort - Department of Chemistry & Biochemistry

Dr. Montfort studies macromolecular structure and function at atomic resolution using X-ray crystallography. Most of the problems we study address fundamental aspects of protein function using medically relevant examples. Examples are (1) ligand-induced conformational change using the enzyme thymidylate synthase (TS) a potential anti-cancer drug. (2) A second anticancer drug target in the laboratory, the protein thioredoxin(Trx), which exists not only in the cytosol, where it serves as a reductant, but also outside the cell where it stimulates certain growth factors to function more efficiently. (3 A nitric oxide binding protein (NP1) from the salivary gland of the blood- sucking insect Rhodnius prolixus.

• Lisa Nagy - Department of Molecular & Cellular Biology

Dr. Nagy is interested in exploring the genetic basis of morphological diversity. To do this, she asks how developmental regulatory networks known to pattern a particular aspect of morphology in one organism are modified in other related organisms. At the moment, her work focuses on the evolution of arthropod body plans. Arthropods show a large degree of variation in segmental and limb patterning. Segments, or groups of segments, have repeatedly become specialized for feeding, walking or swimming. Many of the key genes and genetic pathways that regulate segmentation and limb formation have been worked out through molecular genetic analyses in Drosophila. For example, these genes include the HOX genes or the early segmentation genes linke hunchback, wingless, and engrailed. Dr. Nagy is examining whether morphological evolution involves regulatory changes in otherwise conserved gene networks. Other areas of interest include the molecular evolution of the HOX clusters, the developmental mechanisms underlying phenotypic plasticity and the evolution of altered life history strategies.

• Lynne Oland - Department of Neuroscience

The last decade of research in neurobiology has provoked what to some has been a startling revision in understanding of the role of glial cells in the developing nervous system. No longer just a matrix for the neurons, glia are recognized now to provide signals for neuronal pathfinding, to serve as a physical substrate for neuronal migration, to release needed trophic factors, and to delineate functional regions of neuropil. Dr. Oland's research, carried out in collaboration with Leslie Tolbert, has focussed primarily on exploring development of the antennal lobe of the moth, a system in which glial cells have a prominent role in the process by which the neuropil is partitioned into glomerular compartments. These glomeruli are complex synaptic regions characteristic of first-order olfactory neuropils in vertebrates and invertebrates alike. Interactions between olfactory receptor neurons and glial cells are essential for the construction of stable glomeruli and for the development of the characteristic shapes of antennal-lobe neurons.

• Dan Papaj - Department of Ecology & Evolutionary Biology

Dan Papaj's laboratory studies the reproductive dynamics of insects in the context of coevolved interactions. They are particularly interested in how the flexibility of an animal's behavior or physiology permits it to maintain high performance in variable environments. Plant-herbivore interactions are our primary focus, but plant-pollinator, host-parasite, predator-prey, intra-sexual and inter-sexual interactions are considered as well. Within this broad context, research topics addressed in our laboratory are diverse: learning and host use, costs of phenotypic plasticity (such as costs of learning), ovarian dynamics, signal detection theory and visual ecology.

• Sairam Parthasarathy - Department of Medicine

Sairam Parthasarathy has a broad background in translational and clinical research in sleep medicine. His current research work is focused on three areas as PI or co-investigator: (a) sleep disturbances and the relationship to inflammation and patient-outcomes in critically ill patients and ambulatory patients; (b) health-services research in sleep medicine with emphasis on CPAP adherence promotion and patient experience; and (c) animal models for intermittent hypoxia and cancer risk.

Linda Restifo - Department of Neuroscience

Dr. Restifo's goal is to understand the genetic bases of normal brain development, and the alterations of brain development that cause neurocognitive disorders such as mental retardation and autism. Her group's mission is to make developmental brain disorders treatable with safe and effective drug therapies. Their methodological approaches combine the power of a premiere genetic model organism with that of primary neuron culture. The Restifo lab uses the fruit fly, Drosophila melanogaster, as a model system to study genetic pathways that control brain development. Abnormalities of brain morphogenesis, neuronal differentiation, and neuronal plasticity are likely to underlie many human developmental brain disorders. Because of the remarkable phylogenetic conservation of genes that cause hereditary mental retardation or autism in humans, and because many brain-development mechanisms are shared by mammals and insects, they can use the fruit fly to better understand these human conditions. Moreover, they believe that the Drosophila system can serve as a valuable stepping stone for discovery of drugs that will benefit human patients with cognitive disabilities.

Michael Riehle - Department of Entomology

Dr. Riehle's lab is attempting to better understand the mosquito’s physiology and use this knowledge to reduce the mosquito’s ability to transmit disease. The mosquito represents an ideal model organism for examining the role of insulin signaling on reproduction and lifespan because reproduction only occurs after the females have consumed a discrete bloodmeal. This gives researchers precise control over the timing and number of reproductive cycles an individual mosquito has during its life. The insulin signaling cascade is one of the key regulators of egg production in mosquitoes and most likely other invertebrates. Another primary focus of the lab is to determine the genetics of aging in mosquitoes. One of the goals of the lab is to genetically engineer mosquitoes with a shortened lifespan, but without a large decrease in fitness. To accomplish this they are inserting constitutively active activators and inhibitors of the insulin signaling cascade into mosquitoes. Expression of these signaling components will be regulated through a tetracycline inducible system, allowing them to increase or decrease insulin signaling as needed. The hope is that by increasing insulin signaling in the mosquito we can reduce the mosquito’s lifespan while increasing its fecundity, resulting in a mosquito with a reduced vectorial capacity that can still compete effectively with wild mosquito populations.

Todd Schlenke - Department of Entomology

Dr. Schlenke's research program uses fruit flies in the genus Drosophila to understand the evolutionary genetics of host-parasite interactions. For example, they have developed several species of endoparasitoid wasps, which are readily observed infecting Drosophila in nature and can be very specialized to particular host species, as model parasites. These wasps lay single eggs in Drosophila larvae and, once hatched, consume flies from the inside out. Flies mount cellular and behavioral defense responses against wasps, but wasps have adaptations for finding host fly larvae, suppressing host cellular immunity, and manipulating host behavior. His lab uses a variety of "omics" tools to understand the molecular genetics of fly cellular immunity and wasp virulence, as well as patterns of host immunity and pathogen virulence coevolution across fly and wasp phylogenies. Dr. Schlenke's research program is also making inroads into the evolution, genetics, and neurobiology of behaviors that flies use to avoid being infected by the wasps and to cure themselves once they are infected, including various self-medication behaviors.

S. Patricia Stock - Department of Entomology

Dr. Stock's research interest is biodiversity of insect-parasitic and pathogenic nematodes and their role in ecosystem function. She is actively engaged in biotic survey and inventory projects in different geographic regions of the world, which allow her to make significant contributions toward the discovery of new species, the understanding of the ecology and behavior of insect-parasitic nematodes and their consideration in biological control and integrated pest management programs. Additionally, she is interested in studying the ecology and genetics of nematode populations from agricultural and natural ecosystems, particularly the study of host-parasite relationships and interactions (including plant and insect-parasitic nematodes), such as phoresis, facultative, obligate parasitism, and pathogenesis. A new research area in Dr. Stock's program focuses on the study of Steinernema nematodes and their bacterial symbionts (Xenorahbdus spp.) as models for understanding mutualistic interactions between animals and microbes. Current research relates to the study of structural and developmental features of the bacterial receptacle in the nematode hosts to better understand the colonization process. Her group is also interested in recognizing the chemical signals and physical interactions that occur between the nematode and their symbionts and how these interactions might affect each organism. Furthermore, they also investigate evolutionary histories of both nematode and bacterial symbionts considering a multigene repertoire and study co-evolutionary histories and diversification of these two partners.

• Nicholas Strausfeld - Department of Neuroscience

Dr. Strausfeld's research focuses on understanding neuronal arrangements and interactions that underlie sensorimotor control systems and pathways that mediate learning and memory of spatial relationships. Three main research projects in his laboratory are (1) the elucidation of the cellular and functional organization of the insect visual system; (2) the functional and structural analysis of brain regions involved in learning and memory; (3) brain evolution in arthropods.

• Bruce Tabashnik - Department of Entomology

The Tabashnik laboratory studies the evolution and management of insect resistance to biological and synthetic insecticides delivered by conventional means or by transgenic plants. Current work focuses on evolution of resistance to toxins from the bacterium Bacillus thuringiensis (Bt), which are the most widely used biological pesticides. Recent commercialization of transgenic corn, cotton, and potatoes that express Bt toxins has increased the chances that pests will evolve resistance to these environmentally benign insecticides. Thus, knowledge about resistance to these toxins will have immediate applications. During 1998, Bt cotton accounted for more than half of Arizona's 300,000 acres of cotton, which provides exceptional opportunities for field and laboratory research. Specific projects now underway include analyses of pink bollworm resistance to Bt cotton and analyses of the genetic and biochemical basis of resistance to Bt in diamondback moth.

• Leslie Tolbert - Department of Neuroscience

Intercellular interactions are essential for the development of the nervous system. The laboratory is interested in mechanisms underlying the strategic role played by sensory axons in guiding the development of their target areas in the brain. Using the insect olfactory system as a model system, the developmental interactions that influence cell shape and synaptic connections are being explored. Research focuses on the cellular events by which olfactory axons induce the formation of structures called "glomeruli", which appear in virtually all olfactory systems, from invertebrate to human. A major finding is that glial cells are essential for the formation of glomeruli. Using light, electron, and confocal laser-scanning microscopy, intracellular dye-injection, hybridoma techniques and immunocytochemistry, autoradiography, and biochemical assays, the laboratory is exploring the nature of the signal from olfactory axons to glial cells, whether the response of glial cells involves the expression of cell-surface and/or extracellular-matrix-bound molecules, and how such molecules affect subsequent neuronal differentiation. Recent results indicate that an array of glycoconjugates, including one that resembles a vertebrate adhesion molecule, stud the surfaces of glial cells and of neurons; Dr. Tolbert's lab is currently are testing whether these molecules are involved in glial-neuronal interactions.

• Theodore P. Trouard - Biomedical Engineering

Dr. Trouard's research interest and activity is in the development and application of magnetic resonance imaging (MRI) and spectroscopy (MRS) for the study of interesting biological systems. MRI and MRS are powerful imaging tools that enable non-invasive investigation of structure and function in vivo. The focus of his research is the application of MRI and MRS to neurological function and disease. Current projects are investigating a variety of neurological diseases including Niemann-Pick Type C disease, Alzheimer's disease, stroke and cancer in both humans and in animal models.

• Urs Utzinger - Biomedical Engineering

Dr. Utzinger's research focus is on the development of optical techniques for the early diagnosis of tissue pathologies and monitoring of drug activity.

The research group's vision is to develop new technologies for tissue assessment that will increase performance of diagnosis, that are cost-effective, and that will increase access to health care.

• F. Ann Walker - Department of Chemistry

The Walker group has a wide range of projects, all of which fall under the general theme of gaining a better understanding of the heme centers in heme proteins that are vital to the life of almost all living organisms. The overall goals of this research are: 1) To evaluate the factors that affect the spectroscopic properties of the cytochromes, including heme substituents, heme reduction level, the nature of the axial ligands; 2) To characterize the nitrosylheme proteins from blood-sucking insects and simulate their behavior with model hemes; and 3) To investigate model hemes and heme proteins by multidimensional NMR spectroscopy.

• Diana Wheeler - Department of Entomology

Dr. Wheeler's research is centered on the physiological basis of caste differences in social insects, especially ants. The relevance of these physiological mechanisms to social organization, ecological interactions among colonies, and evolution of social systems is the primary interest of the research group. Areas of research include regulation of oogenesis, storage of proteins by adult workers and queens, mechanisms of sperm storage by queens, and caste determination.

• John J. Wiens - Department of Ecology and Evolutionary Biology

Dr. Wiens is interested in the origin of biodiversity patterns, including questions such as: why are there so many species of insects relative to other groups? Why are there so many species in the tropics? Why are there more species on land than in the sea? This research integrates topics such as speciation, biogeography, diversification, macroecology, macroevolution, and phylogenetics. More generally, our lab group is interested in studying broad questions in evolution and ecology from a phylogenetic perspective, including species richness patterns, speciation, niche evolution and conservatism, life-history evolution, adaptive radiation, ecological diversification, rates and patterns of morphological change, phylogenomics, and responses of species to climate change. We combine collection and analysis of genetic, morphological, ecological, and physiological data (in the lab and field) with bioinformatic, computational, and theoretical approaches. We are also interested in the theory and methods of phylogenetics. Although much of our work is on vertebrates, we are also interested in other groups and broader patterns of biodiversity.

• Joy Winzerling - Department of Nutritional Sciences

Dr. Winzerling's lab is interested in the effects of iron loading on intracellular iron metabolism and the promotion of cellular oxidative damage in various species and in human disease. A second area of clinical research they have initiated is the study of the effects of iron particulates, free radicals and related compounds in air pollution and cigarette smoke on oxidative damage of human lung cells. In addition to the work in humans, they have isolated and sequenced insect transferrins, ferritins and IRP1s from mosquitoes and moths; these insect proteins are similar to those of mammals. They are in the process of evaluating Manduca sexta as a potential biological model and also are studying the adaption of Aedes aegypti to iron loading provided during blood feeding.

• Michael Worobey - Department of Ecology & Evolutionary Biology

Dr. Worobey's research focuses on the evolution of viruses, particularly RNA viruses. He combines theoretical, methodological, and empirical approaches to use viruses to understand evolution, and to use evolution to understand viruses. His theoretical and methodological work focuses on the processes of recombination and natural selection, key evolutionary forces that shape the genetic diversity of viral populations. This work is motivated by specific biological questions including: (1) What role does recombination play in the evolution of insect-vectored pathogens like dengue virus? (2) When, where, and how did the viruses that cause AIDS originate? (3) Why was the 1918 “Spanish flu” pandemic so lethal? (4) What are the constraints on RNA virus evolution? (5) How can evolutionary insights lead to better HIV vaccines? These questions are being pursued primarily by using phylogenetic analyses of both publicly available sequence data and new data generated from field collections from the Democratic Republic of Congo and from archival tissue samples from around the world.

• Daniela Zarnescu - Department of Molecular & Cellular Biology

Dr. Zarnescu's long-term research interests lie in elucidating the molecular basis for cell polarity and how cellular asymmetry controls diverse processes ranging from neural development and synapse remodelling to cell division, growth and differentiation. To address these significant biological questions members of her lab are using a combination of genetic, cell biological and biochemical approaches in Drosophila melanogaster and various cell culture models.

• Konrad Zinsmaier - Department of Neuroscience

Dr. Zinsmaier is investigating fundamental molecular mechanisms that regulate synaptic structure and function, in particular neurotransmitter release, by undertaking a multidisciplinary approach, exploiting the neuromuscular junction of genetically modified Drosophila as a model system. Currently, his group's research interests fall into three categories: (A) Regulation of Ca 2+ triggered vesicle fusion and G protein-mediated inhibition of Ca 2+ entry by the CSP/SGT/Hsc70 chaperone system. Understanding the action of this regulatory complex in detail will be significant for a basic understanding of synaptic plasticity and for clinical research as CSP and Hsc70 have been linked to psychiatric disorders like manic depression. (B) Regulation of neuroexocytosis by the G protein receptors Methuselah and CIRL. Studies of Methuselah, in particular, show an intriguing relationship between excitatory neurotransmission, stress resistance, and aging. As a potential target of therapeutic drugs, studies of Mth and CIRL may ultimately lead to advances in detecting, treating, or even preventing neurological, psychological, or addictive disorders caused by pathologic transmission pathways. (C) The role of mitochondria for presynaptic function and plasticity. This genetic analysis provides new and unexpected insights for a basic understanding of presynaptic Ca 2+ homeostasis and Ca 2+ secretion coupling with significant implications for clinical research. (D) Regulation of microtubules structure at presynaptic nerve terminals by the small mitochondrial GTPase dMiro. This genetic analysis provides unexpected insights into the relation between mitochondrial transport and microtubules stability and could provide a model system for some forms of human spastic paraplegia.

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