Faculty Research Interests
I am interested in research at the intersection of microbiology and ecology. I study how bacteria and fungi influence ecological processes, and in turn how the environment affects the types of species present and the abundance of microbes. Most of my work focuses on microbes living in soils, since soils are one of the most complex, but least well understood habitats in the world. In particular, I use metagenomic approaches to study how different plant communities affect the balance of bacterial and fungal species in soils, and then how those microbes in turn support plant growth by supplying nutrients and stabilizing soil. If we better understand the connections between microbes, plants, and soils, we can use this knowledge to improve ecosystem health, sustainability, and usefulness to human society.
I am interested in the biology and natural history of Indiana plants. I manage the 100,000 specimen Friesner Herbarium, a collection of pressed and dried plant specimens that serve as a reference for study of the Indiana flora. I am working with a group of botanists throughout the state to computerize our specimen records and to produce an atlas of plant distributions. In addition, I am conducting field and laboratory studies of rare native plants. Goals of the study are to use data from demographic and genetic studies to determine the health of remnant populations and to develop management strategies for their conservation. I am also involved with a group studying the success of a massive prairie restoration The Nature Conservancy is undertaking in northwestern Indiana. I seek student involvement in database management, herbarium operations, field checks of plant occurrences, and genetic studies using starch gel electrophoresis of isozymes.
My students and I focus on the population biology of species in the genus Saprolegnia, a fungus-like protist that is classified in the new kingdom Stramenopila. Using both classical isozyme studies and molecular techniques, we examine genetic variation in natural pond populations and determine the relative importance of sexual and asexual reproduction in the life history of this common saprophyte. Projects can be tailored for students wishing to work in the field, the lab, or a bit of both.
My research is in the field of biomechanics. I am particularly interested in the consequences of flexibility in biological structures. I have investigated flexibility in organisms such as coral reef invertebrates, garden plants, and marine mammals and plan to continue this research in the future. More broadly, I am interested in the interaction between form and function in both plants and animals. Students interested in the material (how strong is spider web?) or structural (why do daffodils twist easily?) properties of local organisms are welcome to my lab.
In general, I'm interested in studying the 'hows', 'whens', 'wheres' and 'whys' of genome rearrangement. Of special interest to me are transposable elements (TEs), which are mobile genetic elements that play a major role in genome reorganization and the creation of new genetic variability. Many TEs are 'activated' in times of stress (either external or internal), thus providing a mechanism for increasing the mutation rate when organisms are most 'in need' of novel variability. I am interested in further investigating the effects of stress (esp. heat, salt, drought and pathogens) on transposition frequency in a wide range of species. Currently, I am examining the frequency of transposition in diploid sweet cherry vs. tetraploid sour cherry, with the prediction that transposition will be more common in tetraploids due to genetic redundancy and reduced selection against transposon activity.
My research focuses on understanding the molecular processes that control the ability of neurons to communicate with one another at specialized cellular junctions called synapses (synaptic transmission). The abundance of synaptic proteins impacts the strength of synaptic transmission, which changes during processes such as learning and memory. A highly conserved enzymatic pathway, called the ubiquitin signaling system, is used by neurons and other cells to control protein abundance and activity. My work utilizes the model roundworm C. elegans as a genetic system in which to identify and characterize ubiquitin pathway enzymes and their substrates that regulate synaptic transmission. To do this, I employ a combination of genetic, biochemical, cell biological, and behavioral approaches. Since there is significant conservation of neuronal proteins between C. elegans and humans, these studies may also provide insight into how synaptic transmission is controlled in the human nervous system. Numerous student projects related to this work are available, and I welcome students interested in these or related questions.
I am interested in how cells are organized to form complex tissues and organs. I use the fruit fly,Drosophila melanogaster, as a model system to study this process. Specifically, my research is focused on the development of a multicellular, organ-like structure, called an egg chamber. Egg chambers are made up of a central cluster of germ cells (one of which will go on to become the mature egg) surrounded by a single layer of epithelial cells (the follicle cells). The egg chamber starts out spherical in shape, but as it grows, it elongates preferentially along the anterior-posterior axis, leading to the formation of an elliptical egg. I am interested in the basic cell biological processes that lead to the final shape of the egg. One process that contributes to egg chamber development is the collective migration of the follicle cells. Cancer metastasis involves the migration of cells to different parts of the body. Therefore, by understanding how cells move together in a simple model system such as the developing fly egg, we may be able to learn more about how this occurs in disease states such as cancer.
I operate in the broad fields of ecology and conservation biology. Most of my research is with amphibians (particularly salamanders) and reptiles, although I am generally interested in organisms that use both aquatic and terrestrial habitats during their life cycles. I am not bound to a particular research methodology; my collaborators - including several undergraduate students - and I have conducted descriptive field projects, reductionist laboratory-based experiments, and semi-natural experiments. Moreover, we are not tied to a narrow focus. Our past research includes work on basic natural history of rare salamanders of the Appalachian region, microbial communities on salamander skin, timing of metamorphosis (or the thereof!) in amphibians, evaporative water loss in snakes, and patterns of life history evolution in lungless salamanders. In the next few years, my research will focus on the urban ecology of turtles and other aquatic and semi-aquatic vertebrates and the effects of pesticide exposure on the behavior, physiology, and life history of tadpoles. Students interested in research in my lab are welcome to join existing research efforts or to develop new projects.
The Urban Turtle Ecology Research Project - U-TERP
The Urban Turtle Ecology Research Project—or more simply, U-TERP—was established in the fall of 2001 with the goal of studying the turtle community located in Central Canal in Indianapolis, IN. Our mission is to understand the persistence of and threats facing wildlife living within one of the largest urban areas in the Midwestern United States.
My research interests are in the areas of behavioral and physiological ecology. Mammals have served as my primary study subjects over the years and I have a specific interest in the ecology of ground-dwelling squirrels. I have worked on the reproductive behavior and physiology of yellow-bellied marmots and I most recently focused on patterns of hibernation in woodchucks. In the future, I plan to continue studying marmots with a specific objective of elucidating the hormonal aspects of reproductive suppression among females. Currently, I am investigating the vocal behavior and distribution patterns of tree squirrels inhabiting an urban landscape. Further, I am very interested in beginning studies on the vocal behavior of Eastern gray tree squirrels. I have worked over the years with many students on a variety of projects centered in behavioral ecology and I welcome any students interested in seeking research experience in the field or the lab setting.
I specialize in plant lipid biochemistry and molecular biology. Vegetable oil isn't just for frying and salad dressing. It's already used in products from cosmetics to airplane parts, and is expected to become increasingly important as fossil fuel supplies dwindle. One approach to the development of new industrial oils has been to study how plants make and correctly store unusual fatty acids. I am particularly interested in the synthesis and genetic engineering of fatty acids containing three-membered rings. Student projects in my lab have involved analytical (gas chromatography, thin layer chromatography), molecular (DNA isolation, cloning strategies, electrophoresis) and sterile (bacteria, tissue culture) techniques.
My research focus is on various aspects of the host-parasite relationship. Utilizing both cell culture and murine model systems, the influence of various bacterial pathogenic mechanisms on macrophage/monocyte and polymorphonuclear neutrophil functions are examined. On the immunological side of the relationship, my laboratory examines various aspects of lymphocyte cytotoxicity. Of particular interest is the role of different cytokines on various cytotoxic mechanisms, particularly apoptosis, that have been shown to be involved in the destruction of foreign cells.
I am an integrative evolutionary ecologist interested in how the function, evolution, and development of animal form and behavior are biased by the integrated nature of whole organisms. My approach is cross-disciplinary and considers not only the ecological and behavioral contexts of the traits in question, but also recognizes the genetic, developmental and physiological contexts in which traits are produced. In short: what are the behavioral and ecological consequences of variation?I utilize a variety of tools, both empirical (lab and field) and theoretical. The bulk of my work, both recent and current, uses butterflies as model systems, to address questions such as the following: What role do wing patterns play in the behavioral and evolutionary ecology of butterflies? How do multiple, developmentally plastic traits in the same organism respond to variable environmental cues? Are these responses adaptive, and how do developmental, physiological and/or genetic constraints affect the responses or their adaptive value? What genes are responsible for phenotypic variation, and are the same genes responsible for variation at multiple levels, i.e. within and across taxa? Ultimately, these questions lead to even more fundamental questions about the role of variation in evolution - how is it generated and what happens to it when natural selection occurs? I am interested in talking to students about research opportunities in my lab. Please contact me if you have an interest in conducting research, even if you don't know exactly where your interests lie!
My major research area of interest is plant developmental biology, where I investigate the morphogenesis of leaves. My students and I conduct descriptive studies of developing leaves using scanning electron and light microscopy, we analyze the genetic regulation of leaf development by investigating mutations in genes that affect leaf form, we conduct manipulative studies on developing leaves in tissue culture using hormones and hormone transport inhibitors, and we characterize the expression of genes believed to be involved in leaf formation by using molecular techniques. The two major organisms I work with are garden pea (Pisum sativum),a model system for compound leaf development, and Bryophyllum calycinum, a plant with an interesting asexual reproductive mechanism involving leaves. I welcome any student interested in working on exciting projects and gaining research experience.