Faculty Research Interests
- Jack Holt, Ph.D.
- Carlos Iudica, Ph.D.
- Erin Keen-Rhinehart, Ph.D.
- Jonathan Niles, Ph.D.
- Alissa Packer, Ph.D.
- Peggy Peeler, Ph.D.
- Tom Peeler, Ph.D.
- Matt Persons, Ph.D.
- Jan Reichard-Brown, Ph.D.
- David Richard, Ph.D.
- Tammy Tobin, Ph.D.
- Pavithra Vivekanand, Ph.D.
Dinoflagellate Studies: I have been seeking environmental cues for occurrence and the onset of reproduction of many different freshwater dinoflagellates, particularly species of Peridinium. Although laboratory manipulations can successfully induce sexual reproduction in most Peridinium species, they do not translate well to understanding the actual onset of sexual reproduction and cyst formation in local environments. Such an understanding of these species might help to explain why they serve as good environmental indicators of the health of ponds and lakes that might be susceptible to acid precipitation. This project is being carried out on two glacial lakes in the upper Volga River basin.
River Studies: I have begun to explore the impacts of local streams on the Susquehanna River. Shamokin Creek, an acid mine impacted stream, flows into the Susquehanna River just below Sunbury. The creek water does not simply dilute into the river. Rather, because of the resistance to lateral mixing in the Susquehanna River, the chemical and physical signatures can be measured more than 3 kilometers downstream from the confluence. Attached algae are used as a means to provide an integrated temporal view of the extended impact of Shamokin Creek. In the future I would like to explore other parts of the Susquehanna River to examine the impact of the heat plume from the Shamokin Dam power plant, the effluent plume from the Selinsgrove sewage treatment plant, etc.
Creek Studies: I have been studying the local creeks (Middle Creek and Penns Creek) since 1997. In this case, I have been using diatoms as environmental indicators of the health and heterogeneity of the creek environments. More recently I have collaborated with Michael Bilger of Ecoanalysts, and formerly of the USGS, to examine attached diatoms in Penns Creek and evaluating their species diversity on rocks together with habitat analyses and the diversity of benthic invertebrates. This research is supported in part by the Susquehanna River Heartland Coalition for Environmental Studies, the Lower Penns Creek Watershed Association, and the Department of Environmental Protection. Students who have worked on this project iin the past two years are Jacob Tomlinson and Nathan Moore.
Acid Mine Drainage Studies: Work at the mouth of Shamokin Creek in the Susquehanna River prompted me to begin studying the influence of Acid Mine effluent on Shamokin Creek. The water during most of the year is stained orange from the Specifically, I have been interested in the biofilm that develops on rocks and other substrates in the stream. The biofilm is made of attached algae, many of which are diatoms, and bacteria. These communities, though not very diverse, are quite robust and pervasive throughout the stream. Thus, their occurrences indicate that the acid mine impact exists throughout the stream, even in areas where mitigation has been attempted. Thus, a baseline of these communities through the seasons should provide a measure against which the success future mitigation attempts can be measured. Furthermore, the biofilms, themselves, may hold the keys to understanding how to repair such impaired streams. I have begun a project with Dr. Tammy Tobin-Janzen (environmental microbiology) and Dr. Chris Janzen (environmental inorganic chemistry) to further explore the nature of the biofilms in Shamokin Creek. This research is supported in part by the Susquehanna River Heartland Coalition for Environmental Studies. Students from my lab who have worked on this project during the past two years include Chris Gehman, Dan Eltringham, and Sarah Heath.
Students who work on the River, Creek, and AMD studies should be prepared to work in a collaborative group with students working on microbiology and environmental chemisty. Furthermore, because several of these projects are supported in part by the Susquehanna River Heartland Coalition for Environmental Studies, they may be working together with students from Bucknell, Bloomsburg, Kings, Lycoming, and Lock Haven.
My research interest has focused on the natural history, ecology, conservation and evolution of Vertebrates. My investigations include studies of morphological and molecular-based systematics, alpha-taxonomy, biogeography, mammalian species diversity, ecology and conservation. I am interested in evolution and macroecology of mammals in particular and vertebrates in general. Because I am relatively new in the area, I focused my attention first on characterizing what vertebrates are around and second on analyzing what they do. I have been gathering information about local diversity of the mammal fauna. One way to know what is around is to sample directly the local communities and generate a list of species present in the area. This method, an invasive technique, requires us to survey vast areas and to use a variety of trapping techniques. An alternative, non-invasive way to characterize the local biodiversity and its ecological ties is to use signs, tracks, hairs, owl pellets, or any other “indirect” mean to document the presence of a species in a particular area.
During 2004, my first research student started a seminal line of research, which overall focus on the diets of several species of local owls. The resulting data provided a start for looking into the ecological links between predator and prey, but also marked the beginning of a series of individual projects depicting the diet of different species of owls as well as providing info on the small mammal fauna of the area. I have located and followed nests of barn owls, as well as two other species of owls, which do not temporally overlap on resource use. This kind of data allows us to know about the “phenology” of the resources and its availability throughout the year.
A year later, two other students started working on a project on dorsal guard hairs on mammals of PA. The “unfinished” product, a pictorial key to identify any mammals of PA using their guard hairs has been part of the research experience of many other students’ cohorts working in my lab and a very useful tool.
Later, I started to collect stomachs from different carnivores from PA. We collected several hundred stomachs of gray and red foxes, coyotes, and minks. Using these stomachs, my students were (and are) working on the feeding ecology of carnivores of different sizes. These data open doors to issues related to resource partitioning, predator-prey relationships, population abundance and seasonal changes of diets and densities of prey items, interspecific competition, etc. All students use reference collections, a hair key other students made, and the identified remains of previous studies. Our reference collection has grown since we started and it keeps growing with every research project we add. Something we are missing yet for the purpose of identification is a pictorial database of morphological characters of all mammal species of PA. The final project could be a pictorial key (based on cranial and post-cranial elements) of the PA mammals.
As a by-product of an almost finished research project on winter diet of American minks, we found parasites (worms?) living inside the mink stomachs. I am reserving these samples for yet another curious student who wants to tackle the following questions: what are these parasites? And how common are they in Minks?
Prior to 2004, I collected a series of sediment samples from a cave in Guam (USA) and those sediments are waiting a research student who wants to start identifying the remains to eventually reconstruct the fossil fauna of vertebrates before the destructive and aggressive tree brown snake was introduced in this interesting island of the Micronesia.
Also, collected on previous years before SU, I had a series of owl pellets from Northwestern Argentina (a contact area between mountain rain forest and dry savanna forest) that needs to be identified and ordered.
For the last three years, I have been excavating a local quaternary cave, extracting systematically sediments rich in vertebrate bones. I have probably over 100 samples that require long hours of work under a dissecting scope and most likely a visit or two to a museum collection for ID verification of specimens. Preliminary data from a former SU research student (an ecology-biology major) suggested that this cave is rich in vertebrate bones.
To summarize, this is the list of available projects (which I plan to assign to different research students based on my interaction with each one of you):
1- Pictorial atlas of cranial and post-cranial bones of all PA mammals
2- Faunal reconstruction of vertebrates from a cave in Guam (USA)
3- Stomach parasites on American Minks (Neovison vison)
4- Spring diet on Barn owls in Northwestern Argentina
5- Quaternary vertebrate assemblages from a cave in central PA
If interested on these lines of research or something to do with vertebrates, please, contact me or stop by my office 210 B (New Science Building) anytime.
Gestational Programming is a process whereby conditions at a critical period of development have lasting effects on an organism. Studies in vertebrate species from rats to humans support the notion that the prenatal environment extensively influences the development and life-long function of central nervous system (CNS) circuitry responsible for maintaining homeostasis. Prenatal programming may provide a survival benefit by permitting offspring phenotypes adapted to prevailing environmental conditions. For example, in rats, gestational nutritional deficits are associated with offspring hyperphagia and subsequent obesity, advantageous phenotypic characteristics in an environment where food availability is unpredictable. My research is particularly concerned with the effects of prenatal nutrient availability on areas of the brain governing energy balance and reproductive function.
There are 2 major research projects currently underway in the laboratory. The goal of the first project is to determine how prenatal food restriction affects the development and function of gonadotropin releasing hormone (GnRH) circuits in the brain and their ability to respond to energetic challenges in adulthood. For this project, we are using transgenic rats that express green fluorescent protein (GFP) specifically in GnRH neurons to investigate the effects of prenatal low protein diet on the physiology and function of these brain circuits. We examine the GnRH neurons using double label immunohistochemistry and microscopy to identify significant changes in the activation of GnRH neurons in response to energetic signals including food restriction, leptin and kisspeptin. We expect the results from these studies to enhance our understanding of how prenatal nutrient availability affects the ability of the brain transmit energy availability information to the reproductive axis.
Previous studies in rats indicate that changes in the development of CNS neuronal circuits are likely to be responsible for offspring hyperphagia following prenatal energetic challenges; however, very little is known about gestational programming in other rodent species, such as hamsters. Hamsters, unlike rats, are “natural food hoarders,” utilizing food hoarding as an integral part of their normal ingestive behavioral repertoire. Hamsters are also unique because they respond to the energetic challenge of pregnancy by increasing food hoarding, not food intake. Through collaborative studies with Dr. Jill Schneider at Lehigh University, we have recently discovered that energetically challenging pregnant hamsters by preventing food hoarding during days 5-16 of pregnancy produces offspring with increased food intake and body weight and decreased proclivity to hoard food. Therefore, the goal of the second major research project in the laboratory is to determine the neurobiological mechanisms responsible for differences in ingestive behavior in hamster offspring whose mothers were unable to hoard food during pregnancy. Specifically, we are determining to what extent these behavioral differences can be attributed to programmed variations in anorexigenic and orexigenic hypothalamic circuits shown to govern ingestive behavior in other animal models.
My research interests center on the biology and ecology of freshwater fish. In particular I study native coldwater species like the brook trout (Salvelinus fontinalis). My particular interests involve habitat enhancement, watershed protection, feeding ecology, and the life history of this coldwater species that faces an uncertain future as global climate change becomes a reality.
Riparian zone disturbance studies (Middle Fork River, Central West Virginia)
Brook trout (Salvelinus fontinalis) are the only salmonid native to the Appalachians. They are an important recreational resource and an indicator of aquatic integrity in forested watersheds. Management of forested watersheds to maintain and even enhance habitat, water quality, and brook trout is critical to sustainable forest management in the Appalachian region. It is estimated that in some states upwards of 25 percent of the timber falls within the riparian zone. There are concerns arising over timber harvest in the riparian zone such as possible increases in water temperatures and other aspects that could prove detrimental to coldwater stream fishes like brook trout. However, the tradeoffs between increases in instream productivity from riparian harvest and increased canopy openness are difficult to predict. My studies evaluate the effects of a manipulative experiment in the riparian zone of eight Appalachian forested watersheds in order to determine: (1) the effects of increased solar radiation and large woody debris additions on in stream habitat and brook trout population dynamics, size and condition, and dietary energetics.
Unassessed Pennsylvania Water’s Initiative (Loyalsock and Muncy Creek, Northern Pennsylvania)
Although Pennsylvania contains 64,345 streams totaling approximately 86,000 miles of flowing water in Pennsylvania, the Pennsylvania Fish and Boat Commission has only been able to conduct “baseline” surveys and implement management strategies on a small portion of the total streams. As a result, only 8% of the streams and 29% of the total stream miles are being actively managed. Of the waters remaining, many likely support wild trout populations. The primary threat to unassessed wild trout waters is inadequate water quality protection due to the unknown condition of trout populations and the resulting permitting actions that are not properly conditioned to protect wild trout. The importance of adequately protecting streams has increased dramatically with the recent expansion of Marcellus Shale gas extraction throughout much of the state.
Opportunities exist to protect known wild (brook and brown) trout populations as well as expand the number and miles of streams officially designated as wild trout waters through the examination of waters that have not been inventoried to date. My lab will collect baseline data and document the status of wild (brook and brown) trout populations in waters that have not been inventoried, but are expected to support wild trout. In addition to the collection and sampling of trout populations in these streams, we also collect other biological data within these stream systems. At each site we collect aquatic benthic macroinvertebrate data as these communities are particularly sensitive to changes in land use, flow alteration, water temperature, and pollution. This research has the potential to protect ecologically important and previously unassessed streams which can lead to increased protection of Pennsylvania waters.
Brook trout habitat preferences and instream temperature assessment (Meduxnekeag River, Northern Maine)
The state of Maine has the highest percentage of intact populations of brook trout in the eastern United States. The stream population of brook trout across the state is estimated, because many streams have not been surveyed and the population status is largely unknown. Management of watersheds to maintain and even enhance habitat and water quality for this important species is critical to sustainable fisheries management in this region. The mainstem Meduxnekeag River significantly warms throughout the summer, creating conditions that forces brook trout to seek temperature refuge during this critical time of year. Brook trout are frequently caught in the Meduxnekeag River during the spring and fall, however during summer trout must seek refuge from the low river flows and higher instream temperatures. It is currently unknown where brook trout move in the system during the stressful summer season. Because of their sensitivity to warmwater temperatures, salmonid populations could be either reduced or eliminated by increases in summer temperatures. Stream temperatures may differ at various locations and may include localized coolwater areas that could serve as thermal refuges, allowing the survival of fish that are sensitive to high temperatures. Because brook trout require relatively cool summer water temperatures, coolwater refuges may be important for survival in streams that have lethal water temperatures (>25°C) during the summer. A detailed description of the use of thermal refuges by adult brook trout is generally lacking in the literature. The lack of deep pools and appropriate summer brook trout habitat in the Meduxnekeag mainstem may place greater importance on coldwater refugia that may exist in some mainstem areas or in tributary streams. It is currently unknown where summer brook trout populations persist along a wide stretch of the mainstem and tributary streams. My lab will assess summer brook trout summer habitat use to determine where brook trout seek refuge in the river during this critical time of year.
Alissa Packer, Ph.D.
My research explores the role of direct and indirect defenses in several plant species. All of the plants that I study produce hydrogen cyanide (HCN) when damaged, which acts as a direct defense by killing or slowing growth of the animals that consume the plant tissue. The plants also produce extrafloral nectaries. These extrafloral nectaries (EFNs) are structures that produce nectar outside of the flower. EFNs are structurally diverse and occur on many different parts of the plant, including the leaves, stems, petioles, stipules, flower stalks, and outside of the flowers. EFNs are thought to serve as an indirect defense because they don’t kill herbivores directly, but instead function to attract herbivores’ natural predators (often times ants), i.e. the plant gains protection by luring in its enemies’ enemies (an enemy of my enemy is my friend). The relationship between plant and ant is considered mutualistic; plants provide the ant with a nutritional reward (nectar in EFNs) and in return the ant provides the plant with protection from herbivores.
A question of great interest to ecologist is how ecological and evolutionary factors affect the expression of direct and indirect defenses in plants. Little research has been done to investigate the abiotic factors influencing the production HCN and EFNs. For instance, light, nutrient and water availability all affect the photosynthetic capacity of a plant. Sugar produced via photosynthesis is required to attract ants and other insects to the EFNs, and nitrogen from the soil is necessary to produce HCN. Little is known about how these abiotic factors influence the production of nectaries, the amount of nectar found in an EFN, or the level of HCN in plant tissue. Further, we know little about whether trade-offs exist between investment in direct and indirect defenses.
In addition to classifying defensive traits as direct or indirect, ecologists also consider whether plant defenses are constitutive (i.e. always present on the plant) or induced (i.e. produced in response to herbivore damage). Work in my lab has shown that EFNs can be induced in response to both mechanical and real damage by herbivores. When damaged, plants increase their production of EFNs on leaves. We are continuing to explore how HCN levels are influenced by damage.
My lab is also interested in exploring questions of plant-plant communication. Can plants warn one another if an herbivore attack is imminent? Animals often send warning calls. Ecologists are finding that the same is true of plants, though the mechanism is much different. Plants release volatile chemical cues into the air when damaged. There is emerging evidence that neighboring plants can detect these chemical cues, and “turn on” induced responses prior to an actual attack. My research explores whether this occurs in the species that we are studying.
My research offers opportunities for field, greenhouse, and lab work, depending on students’ interests. Ongoing and future research will address the following questions: 1.) How does light, water, and/or nutrient availability affect the production of EFNs and HCN?, 2) Are there trade-offs between these two defensive traits?, 3) Are these defenses inducible (in response to damage to the plant)?, and 4) Can these defenses be induced in undamaged plants in close proximity to damaged neighbors?.
Gene regulatory control of cell fate and morphogenesis in sea urchin embryonic development
As animal embryos are constructed after fertilization, two separate but related processes occur. Cells in the embryo undergo differentiation, meaning that they express the genes and proteins needed for their specific function, and they participate in morphogenesis- the creation of shape within the embryo. Morphogenesis typically requires wide-scale cell movements, initiating at the stage of development known as gastrulation. We are interested in understanding the ways in which differentiation and morphogenesis are coordinated, so that a complete embryo, with the right cells in the right places, can be constructed.
Sea urchin embryos have been a classically studied model system in developmental biology for a century or more, and we have very detailed knowledge about the cellular aspects of their development- when the cells divide, where and when they migrate, and what their ultimate fate will be in the embryo. However, we have a more limited understanding about the genes that direct these developmental processes. But now that the sea urchin genome project has been completed, we have a treasure trove of gene sequences to try to match up with what we know about the cells and their behaviors. Student projects will be focused on characterizing the signaling pathway that triggers the cell movements needed to construct the digestive system present in the larval sea urchin, called the archenteron. We are particularly interested in investigating the role of a signal transduction pathway called the Planar Cell Polarity pathway. Current work is centered on a component of this pathway- a kinase known as JNK, which appears to be critical both for early cleavage, and for cell migration during gastrulation. We have shown that inhibiting JNK prevents invagination, which is the initial cell movement required for archenteron formation, and are working to characterize what proteins are downstream of JNK that might directly trigger invagination.
Lab techniques will include embryo culture and a number of molecular approaches such as RNA isolation, standard and real-time PCR, cloning and sequencing, Western and Northern blotting, immunolocalization and more. Having taken Developmental Biology, and either Molecular Biology or Cell Biology would useful. My students this year are Caitlin Kelly, Lauren Shuman, and Abbie Handerhan. Please feel free to ask them about their experiences.
My research focuses on the interactions that take place between Schwann cells, the extracellular matrix, and peripheral nerve axons. Schwann cells are best known for wrapping layers of myelin around peripheral nerve axons, which facilitate more rapid conduction of nerve impulses. Schwann cells also help to create a pathway for peripheral nerve axon growth during development.
Work during the past year has focused on the role of beta-8 integrin in signal transduction in Schwann cells. Integrins are a family of transmembrane proteins that link the cytoskeleton to the extracellular matrix. We used Western blotting to determine that the GDP Dissociation Inhibitor (GDI) binds to the cytoplasmic portion of beta-8 integrin in Schwann cells. We plan to study the role of GDI in signal transduction in the future. I collaborate on this project with a group of scientists at the Weis Center for Research at the Geisinger Clinic, in Danville, Pa. My work, along with the ongoing research at the Weis Center, is enabling us to better understand how Schwann cells help to guide peripheral nerve axons during development. The students that worked on this project this year are Lindsay Bailey, Nick Corridoni, and Paul Russick.
In addition, during the 2009-2010 academic year, two students performed genotyping studies in collaboration with scientists at the Weis Center for Research. Marissa Rejent analyzed samples from a population of patients with abdominal aortic aneurisms (AAA), and Sam Thomas analyzed samples from a population of patients from the obesity clinic at the Geisinger Medical Center. Marissa and Sam used PCR to determine the association of specific single nucleotide polymorphisms (SNPs) with either AAA or obesity. The results of their research may lead to tests that can be used to screen patients for AAA, and may contribute to our understanding of the causes of AAA and obesity.
Behavioral Ecology of Wolf Spiders
Behavioral ecology focuses on understanding the adaptive significance of the ultimate in phenotypic plasticity- behavior, as well as the selective pressures that have shaped its evolution. I use wolf spiders as the primary model organism for understanding the survival and reproductive consequences of the decisions that animals make. Wolf spiders are ecologically and economically important because they reside at the interface of terrestrial and detrital food webs and are the numerically dominant predators in most agricultural systems. Despite their importance, their precise role in regulating arthropod densities remains poorly understood.
Like all spiders, wolf spiders deposit silk draglines as they move through the environment. I am particularly interested in understanding how these draglines are used as a source of information that mediates predator-prey interactions between wolf spiders, their predators, and their prey. I am also interested in the role of dragline silk within the context of sexual communication. Females and males may use silk to advertise their willingness to mate. Some recent research suggests that male and female spiders may manipulate the quantity and type of silk produced during courtship and mating interactions based on the probability of finding a mate as well as the quality of prospective mates. Our lab is trying to decipher the ‘language’ of silk since spiders produce more than one type of dragline. Other major areas of study include foraging behavior (how spiders search for prey and choose among available prey types), communication (content and effectiveness of courtship and aggression displays), female and male mate choice (behavioral and morphological criteria for choosing mates), maternal care (why wolf spiders carry their egg sacs and offspring), mating systems (why spiders do or do not mate multiply), learning (how spiders recognize predators, prey, siblings, and potential mates), and cannibalism (criteria and context for feeding on other wolf spiders). Our lab is also examining the impact and potential of spiders as biocontrol agent in local agricultural systems. Current senior research students are Meg Marchetti, Mickey O’Donovan, and Mike Platt. Rizwan Khan is also conducting research with me. Feel free to contact any of these students regarding their research experiences.
More recently I have also been conducting studies on the information content, context, and adaptive function of urine marking in domestic dogs.
Visit my personal Web page <http://www.susqu.edu/facstaff/p/persons/default.htm> and go to "Research Opportunities and Projects" for abstracts of current and previous student projects or see my CV for abstracts of presentations and published work.
I have a research interest in the drug thalidomide. Thalidomide is the drug, which was given to pregnant women in the early 1960s to control morning sickness. Unfortunately, when that drug is given early in pregnancy it has a teratogenic effects resulting in babies being born with limb reduction deformities. Even now, forty years later, there are no clear explanations for the effects of thalidomide during early pregnancy. Part of the problem is that thalidomide affects humans and some species of monkeys but it does not seem to affect standard mammalian laboratory animals in the same pattern. I am currently using sea urchin embryos as models organisms for thalidomide research. This model system is fairly successful in that we are able to show a statistically significant increase in abnormal developing sea urchin pluteii in the thalidomide treated group. We are also able to demonstrate a predicable dose response curve. There is strong evidence that sea urchin embryos exhibit at least two windows of vulnerability during the first 72 hours of their development in culture. We are now at the point to start looking for specific mechanisms of action for the teratogenesis induced by this drug. We will be focusing on some common cell cytokines. Techniques which will be used to continue this project include immunofluresence and PCR for examining gene expression and protein gel electrophoresis. Since thalidomide is back on the pharmaceutical market under a different name for treating leprosy and some of the symptoms of chronic illness , the project is timely and relevant. Students currently working in my lab include: Eric Siminitus, Ashley Mill, Adam Saterson and Kevin Barron. I am also supervising a student assistant, Josh Wrubel who works on the project as well.
The control of egg production in Drosophila.
Many insects act as vectors for human diseases such as malaria, sleeping sickness, and West Nile virus. Others are significant agricultural pests causing billions of dollars of damage to crops each year and requiring large-scale insecticide intervention. The development of rational control strategies, rather than utilizing insecticides, may provide a environmentally acceptable solution to these insect control problems and one possible locus of control is reproduction. My lab investigates the endocrine and genetic basis of control of the process of yolk protein (YP) production and uptake (vitellogenesis) in the fruitfly Drosophila melanogaster during egg production. YP production is apparently under the control of both juvenile hormones (JHs) and ecdysteroids and its uptake is mediated by the insulin-signaling pathway.
Recent work has focused on the insulin-receptor substrate gene (chico) as an important ovary-autonomous factor driving receptor-mediated endocytosis of YPs. Mutations in this gene cause female sterility, decreased growth and extended longevity, clearly making this gene of interest in a number of areas of biology. The interaction of JH and the CHICO protein with ovarian proteins involved in receptor-mediated endocytosis is presently under investigation. Techniques used by students in my lab in recent years include mRNA extraction, Real Time PCR, Semi-quantitative Reverse Transcriptase-PCR, DNA purification/sequencing, confocal-laser immunofluorescence microscopy, Western blotting, microinjection and fly stock management. Current seniors are Emily Strittmatter and Jessica McGill along with juniors, Sam Berkheimer and Adam Petrone.
Molecular Biology and Microbial Ecology of Bacteria Living in Extreme Hot Soils Above the Centralia, PA Mine Fire
My lab uses molecular biology techniques such as PCR, DNA cloning and DNA sequencing together with traditional microbiology analyses and field studies to try to understand the effects that coal mine-impacted environments are having on their resident bacterial communities (and vice versa). We also use these same techniques to identify new bacterial species that thrive in the altered coal mining environments, and that may have important biomedical, industrial and ecological applications. My current senior research students are Trevor Bell, Erin Nardella and Michael Petronaci. Tiffany Becker and John Dryburgh are also working with me this year. Please feel free to contact any of them regarding their experiences. Their projects are summarized below.
Identifying and isolating new antibiotic-producing bacteria. (Michael Petronaci and Tiffany Becker). The emergence of pathogenic bacterial strains that are resistant to multiple (and sometimes all!) existing antibiotics has made it crucial for us to find new sources of antimicrobial drugs. Students involved in this project will identify and isolate potential antibiotic-producers from hot soils above the Centralia mine fire, and test the isolated bacteria to determine if they do produce any antimicrobial products through a collaboration with Dr. Geneive Henry in chemistry. Ultimately, we hope to discover antibiotics that will not only be effective against currently resistant strains of bacteria, but that will also be active at elevated temperatures (and thus be more shelf-stable than current antibiotics).
Thermal vent ecology near 'anthracite smokers' (Trevor Bell and Erin Nardella): The current Centralia landscape is marked by active steam vents, called 'anthracite smokers,' that heat and deposit dissolved chemicals from the mine fire below into the surrounding soils. Recent evidence suggests that previously unknown thermophilic nitrogen- and sulfur-metabolizing bacterial species now thrive in the soils above the mine fire, presumably taking advantage of the high levels of these chemicals in the soils. Students involved in this project next year will have the opportunity to work closely with faculty in the departments of Earth and Environmental Sciences and Chemistry. In particular, these students will try to identify microbial community members that could be used to bioremediate the fire-impacted soils, or that might be playing important roles in nutrient cycling and the release of greenhouse gases. .
Specification of glial cells in the Central nervous System of Drosophila
My broad area of research interest is to understand how different cell types are specified in multicellular organism. We are focusing our attention on dissecting the molecular mechanisms that regulate the differentiation of glial cells within the central nervous system (CNS) of Drosophila. The CNS of Drosophila, like that of vertebrates is bilaterally symmetrical and consists of two major cell types, neurons and glia. Intricate cellular and molecular interactions between non-neuronal glial and neuronal cells play an integral role in the development of the CNS of both vertebrates and invertebrates.
For instance, glial cells are required for establishment of the blood-brain barrier, for neuronal proliferation, survival, insulation and axon pathfinding. The disease multiple sclerosis (MS) results from the destruction of a specific type of glial cell that leads to defects in the ability of neurons to conduct electrical impulses. This underscores the importance of maintaining an exquisite balance between glial and neuronal cell populations for proper nervous system function. Students will have an opportunity to obtain hands on experience with a number of molecular, cell and developmental biology techniques such as cloning, PCR, in situ hybdridization, immunocytochemistry and transcription assays to determine how gene expression is regulated in embryonic glial cells of Drosophila.
I have been recently awarded a luminometer through an instrument grant from Promega Corporation, which will allow us to perform transcription assays in Drosophila cultured cells. This will enable us to determine whether manipulating the regulatory regions of target genes alters their expression levels.