Participating Faculty Mentors
|April Blakeslee, Ph.D.
||Ted Brummel, Ph.D.
|Daniel Ginsburg, Ph.D.
||Kent Hatch, Ph.D.
||Steve Liebling, Ph.D.
|Karin Melkonian, Ph.D.
||Grace Rossi, Ph.D.
||Scott Santagata, Ph.D.
|Jennifer L. Snekser, Ph.D.
||Stephen Tettelbach, Ph.D.
April Blakeslee, Ph.D.
Dr. April Blakeslee's research centers around global distribution patterns and processes in marine systems, including biodiversity, conservation biology, population genetics, parasite ecology, and biogeography – with a special focus on the unique and integrative insight that can be gained from studying biological invasions. Recently, biological invasions have become recognized as a major contributor to the global (and often disjunct) distributions of many marine species as a result of their movement and establishment via human transport mechanisms. Over the years, Dr. Blakeslee has examined many integrative aspects of invasion biology and has used intertidal marine invertebrates, especially mollusks and crustaceans, as model organisms because they have contributed numerous marine introductions globally. This summer she plans to continue that research, exploring competitive interactions of invasive species with natives. This project includes field work, lab work, and travel, and interested students will learn various aspects of marine ecology, behavioral ecology, parasitology, and invasion biology. In addition, there may be opportunities to explore population genetics related research in Dr. Blakeslee's lab.
Blakeslee, A.M.H., A.E. Fowler & C.L. Keogh (2013) Marine invasions and parasite escape: updates and new perspectives. Advances in Marine Biology. 66: 87-169.
Freeman, A.S., A.M.H. Blakeslee & A.E. Fowler (2013) Range expansion of the rhizocephalan Loxothylacus panopaei (Gissler, 1884) in the northwest Atlantic. Aquatic Invasions. 8: 347-353.
Blakeslee, A.M.H., I. Altman, A.W. Miller, J.E. Byers, C.E. Hamer & G.M. Ruiz (2012) Parasites and invasions: a biogeographic examination of parasites and hosts in native and introduced ranges. Journal of Biogeography 39: 609-622.
Pringle, J., A.M.H. Blakeslee, J.E. Byers & J. Roman (2011) Asymmetric dispersal allows an upstream region to control population structure throughout a species' range. PNAS 108: 15288-15293.
Panova M., A.M.H. Blakeslee, A.W. Miller, T. Mäkinen, G.M. Ruiz, K. Johannesson & C. André (2011) Survival of a North Atlantic marine snail in multiple glacial refugia—implications for phylogeographic patterns. PLOS One 6(3): e17511.
Blakeslee, A.M.H., C.H. McKenzie, J.A. Darling, J.E. Byers, J.M. Pringle & J. Roman (2010) A hitchhiker's guide to the Maritimes: anthropogenic transport facilitates long-distance dispersal of an invasive marine crab to Newfoundland. Diversity and Distributions 16: 879–891.
Ted Brummel, Ph.D.
Genetics of Aging
A growing body of evidence suggests that it is possible to manipulate genes in order to significantly extend lifespan. Many genes that control the aging process also play a role in nutrient sensing and utilization. We have recently shown using Drosophila melanogaster that the diacylglycerol lipase gene modulates longevity by down regulating the Target of Rapamycin (TOR) signaling pathway. Since TOR is a key intracellular nutrient sensor that plays a key role in modulating not only aging but also cancer we are using these mutant to understand the molecular mechanisms that modulate these pathways. We are focusing on understanding how the manipulation of this gene affects a number of key aspects important for understanding aging.
Since TOR signaling is important for nutrient sensing and in most organisms dietary restriction (the alteration of either caloric intake or nutrient balance) can extend lifespan we evaluating how alterations in TOR signaling affect caloric intake and food preference by using the Capilary Feeding (Café) assay to measure caloric intake and feeding behavior.
Since alteration in TOR signaling or dietary restriction enhance stress resistance we are also testing how dietary restriction and TOR signaling influence caffeine and nicotine toxicity and are also working on evaluating whether manipulations in these pathways can alter drug avoidance or drug seeking behavior.
Since the presence of microorganisms (bacteria and yeasts) can modulate not only the lifespan of the fly, but also serve as source of nutrients we are investigating how exposure to microbes differentially affects gene expression in wild type and mutant flies under different dietary regiments, as well as how these manipulations affect the ability of microbes to colonize their fruit fly hosts.
Since dietary intake and nutrient utilization are so critical for the modulation of aging we are using Stable Isotope Analysis as a tool to track the fate and utilization of dietary protein in the fly. This approach should provide a long-term measurement of nutrient utilization which will complement the gene expression data generated using Western blots or mRNA expression measurements.
Daniel Ginsburg, Ph.D.
Humans have 25,000 different genes, but not all of them are being expressed in all cells. In fact, the regulation of gene expression is crucial in many aspects of cell regulation and metabolism. The ability to turn on and off genes allows cells to respond to external stimuli, differentiate, survive, and grow. The first step in gene expression is transcription, synthesizing an RNA molecule from a DNA template. Our lab studies the molecular mechanism of transcription. One of the primary regulators of transcription is chromatin, the protein-DNA complex that makes up the chromosomes in eukaryotic cells. Chromatin limits what proteins have access to the DNA, so it must be altered for transcription to take place. We investigate how changes in chromatin and transcription are linked. We focus on a couple specific chromatin changes and look at how they affect the binding of different protein complexes to chromatin. We use yeast as our model organism, because they are fast-growing, easy to manipulate, and at the level of transcription, identical to higher eukaryotes. Our lab carries out experiments involving molecular biology, genetics, and biochemistry, and we are looking for motivated students to contribute to our ground-breaking research.
Kent Hatch, Ph.D.
Background for Project 1
Stable isotopes have been used extensively to study migration, diet, and trophic levels (steps up the food chain) among wild animals. However, these studies are based on many assumptions that have gone untested in either the lab or the field. This is particularly true concerning the study of trophic levels based on 15N/14N ratios of tissues. As one moves up the food chain the 15N/14N ratio of the animals increases. It is commonly assumed that the 15N/14N ratio increases by 3.4 parts per thousand (relative to a standard) with each complete step up the food chain. However, it has become increasingly apparent that this does not hold true across species. Interestingly, very few controlled laboratory studies have actually been done to assess how 15N/14N ratios increase as trophic level increases.
We propose to study the effect of trophic level on 15N/14N ratios in the most clear manner possible by studying the effects of cannibalism in insects on trophic levels. This eliminates any confounding factors that may be caused by feeding different prey species to different predators. Prey species may not all be at the same trophic level, and therefore neither might the predator species. By examining the effect of cannibalism on 15N/14N ratios we know we will be measuring the pure effect of trophic level on the stable isotope ratios. To do this, we will use crickets and mealworms. Each species will be set in an isolated system where they will be fed a previous generation of the same species in an effort to generate the pure effect of trophic level on the stable isotope ratios of 15N. We predict a constant increase within a species of the 15N/14N ratio of the tissues with increased trophic level. However, we predict that this value will differ between the species.
Background for Project 2
Toe clipping is widely used as a method of marking amphibians typically for mark and recapture studies. It has more recently been utilized to gather information on genetic studies, histological examinations and age determination of the amphibian. However, there is little data on the survival rates or overall fate of toe clipped individuals. There has been previous research suggesting that with the increase of toes clipped, the overall recapture rates significantly decrease. (McCarthy and Parris 2004) These decreased recapture rates may have different causes, not related to survival.
This study aims to look at the overall survival rates of toe clipped frogs by measuring activity rate, growth rate, recapture avoidance and death. Currently it is unknown if toe clipping has a detrimental affect of these animals. This is important to look at because toe clipping is often used for population estimations. By gaining a better understanding of what happens to the animals after toe clipping we can determine if these estimates are indeed correct or if there is something else occurring.
Steve Liebling, Ph.D.
For those interested in computational physics and with appropriate background research opportunities include: (i) solving ordinary differential equations for interesting solutions such as topological defects in some particular spacetime, (ii) solving partial differential equations for some nonlinear wave equation looking for critical behavior or global existence, and (iii) implementing certain numerical techniques on GPUs or other accelerators using advanced parallel methods such as OpenCL. A background which includes calculus and programming is required, and the expectation is for someone majoring in mathematics, physics, or computer science. However, outstanding and curious students of any major will be considered. Any experience with Linux or Unix is helpful, but not required.
More information about Dr. Liebling's research is available.
Karin Melkonian, Ph.D.
My laboratory has focused for many years on the antimicrobial testing of modified carbohydrate- and protein-based surfaces (wood, paper, cotton, silk, wool, etc.). The novel modification destroys microorganisms through first a pirecing then and electrocution mechanism. These surfaces have been found to be antibacterial and antifungal against a number of pathogenic organisms (including P. aeruginosa, S. aureus, E.coli and B. anthrasis, the bacteria that causes anthrax and C. albicans). The lab is currently examining the antiviral effect of these surfaces. We are infecting eukaryotic dog kidney cells with influenza virus and testing whether they provide any antiviral protection to the cells. Additionally, we have shown these surfaces to be anticoagulating. Having both antimicrobial and anticoagulating properties provide many potential important medical uses for these surfaces, such as production of blood bags, wound dressings, etc. We are interested in further characterizing the anticoagulating effect and understand the biochemical reactions involved for future therapeutic use.
Recently, my laboratory has begun a new project involving the specialized hairs on tarantulas. We have determined that these hairs provide a new method of bacterial transfer. We isolated bacteria from the urticating (stinging) hairs of the Goliath Bird-eating spider,Theraphosa blondi. Several different species of bacteria were identified based on DNA sequence. When threatened, a tarantula shoots urticating hairs at the threat. These hairs are believed to enter the victim’s nasal passages, causing irritation and asthmatic symptoms. However, our research suggests that the bacteria isolated from the hairs may contribute to the breathing difficulties observed. We have found that one isolated bacteria produced a viscous mucus-like secretion. Therefore, we hypothesize that the bacteria associated hairs enter the victim’s nasal passages and thrive. These bacteria then produce a mucus-like material that clogs the victim’s respiratory passages. Currently, our lab is examining the effects of the bacteria on mice. This study may be significant in understanding a potentially complex relationship between the spiders and their victims/prey. Studies include observations of respiratory distress, blood cultures, bacterial cultures and lung histology. Simply startling a tarantula can result in the release of their bacteria-associated hairs. Therefore, the simple act of cleaning a tarantula cage or disturbing the ground around a spider’s hole can cause dispersal of the hairs that are subject to inhalation. Therefore, this research may have an impact on human health, particularly those who may be immune compromised, as there is an ever-increasing popularity of tarantulas as pets. In additions, tarantulas are a force protection issue as they are found in high abundance in areas where United States Forces are operating.
Grace Rossi, Ph.D.
Dr. Rossi's laboratory focuses on the pharmacological characteristics of the opioid system through the use of molecular and behavioral techniques. Over the past year Dr. Rossi and her collaborators at Memorial Sloan Kettering Cancer Center have identified and characterized spliced variants of the mu-opioid receptor that are involved in chronic pain and analgesia. These studies involve detailed micro-injections while analyzing blood pressure, analgesia, inflammation, motor skills, and place-preference conditioning. Studies are performed on mice that have been genetically modified and lacking a selective opioid gene.
Since the cloning of the first opiate receptor, opiate pharmacology has become increasingly complex while the population of chronic pain sufferers increases. The overall goal in this laboratory is to further characterize the opioid receptor system in order to better treat chronic pain conditions without producing side effects such as tolerance, dependence and addiction. To do this, one must examine the actions of several known opiates as well as newly synthesized compounds at the level of the spinal and supraspinal nervous systems.
Requirements: Person must be at least 15 years of age, willing to handle mice, and adeptly skilled in basic handling techniques.
Xu, J., Xu, M., Rossi, GC., Pasternak, G.W., and Pan, Y-X. Identification and characterization of seven new exon 11-associated splice variants of the rat mu opioid receptor gene, OPRM1. Molecular Pain; (2011), Jan 21;7(1):9.
Rossi, G., Barbut, D., Richelson, E., Matulonis, J., and Pasternak, GW. Systemically and topically active antinociceptive neurotensin compounds, Journal of Pharmacology and Experimental Therapeutics, (2010) Sep 1;334(3):1075-9.
Scott Santagata, Ph.D.
Project Description: Experimental demonstration of the functions of larval sense organs among the lophophorates: ectoprocts, phoronids, and brachiopods.
In collaboration with Dr. Jonathan Allen and his undergraduate students from the College of William and Mary, we will use both blastomere separation and microlaser ablation techniques to manipulate energy content in marine invertebrate embryos, testing the effects of reductions in energy on larval duration, size at metamorphosis and post-metamorphic success. We propose to expand the taxonomic breadth of the work by adding data from severely understudied phyla, namely the lophophorates: brachiopods, phoronids, and ectoprocts. We would also take further advantage of the laser ablation system to advance Dr. Santagata’s research interests in the function of ciliated sensory cells and neurons in lophophorate embryos and larvae. Eumetazoan ciliated sensory cells and neurons likely evolved from simple multifunctional ciliated cells. Such cell types are common among the larval types of lophophorates. Therefore, these larval forms provide an excellent opportunity to explore the functions of various multiciliated sensory cells during phototactic and settlement behaviors. For our combined work, we will gather candidate species collected from sites in Maine near Bowdoin College's Coastal Studies Center. We would then use cell ablation, cell labeling, and microscopical techniques as well as pharmacological treatments to test various developmental, sensory, and behavioral hypotheses. Specifically, one of our main goals will be to investigate the role of specific sensory neurons (larval ocelli) during phototactic behaviors. Beyond phototactic behaviors, evidence from the expression patterns of developmental regulatory genes supports the hypothesis that centrally-positioned neuronal cells in the apical sense organs of most eumetazoan larvae share a common evolutionary origin. These ciliated neuronal cells may share key functional roles in the reception and transduction of settlement and metamorphic cues. We will use the laser ablation system to eliminate subsets of these sensory neurons and document the downstream behavioral and metamorphic effects from which we will infer shared or divergent neuronal functions. One undergraduate student will be recruited to participate over a 10-week period in the initial phase of our collaborative research plan. The undergraduate research training will include facets of organismal, evolutionary, cell, and developmental biology.
More information about Dr. Santagata's research is available.
Jennifer L. Snekser, Ph.D.
The focus of Dr. Snekser’s research program is to understand the ecological and evolutionary implications of different individual behavioral types within populations (i.e., behavioral syndromes). Anyone that has had a pet or spent time at a zoo has probably thought that animals seem to have specific personalities. Individual animals respond consistently and predictively based on their temperament, also called a “personality” or “behavioral type”. Early work on animal personality and behavioral syndromes has focused on description and we now seek to understand personality within the context of ecological systems and evolution. It is debated what influence (if any) behavioral syndromes may have on evolution. On one hand, consistent personalities would seem to constrain individuals from adapting. Conversely, the correlation of behaviors may actually drive evolution by supplying a proportion of the population that has ideal behavioral traits all linked together, making them more suitable to establish new, stable populations. Previous projects have shown that significant correlations can exist among behaviors, implying that behavioral types can be maintained over time, within specific contexts. However, individuals are able to assess the quality of their current territory and adaptively adjust their behaviors (Snekser et al 2009). Thus, while it may appear that behaviors are linked within a syndrome, changes in the environment can disintegrate correlations. Currently, large gaps exist as to the influence of the environment on behavioral syndromes. Additionally, a minimal amount of work has been done to understand behavioral syndromes in animals that live in groups or work as pairs, or that interact with each other. Through laboratory and field work with various species of fishes, the goal of Dr Snekser’s multiple research projects is to better understand the relationship of ecology, genetics, neuroendocrinology, evolution, and behavioral syndromes.
Snekser JL, Leese J, Ganim A & Itzkowitz M. 2009. Caribbean damselfish with varying territory quality: correlated behaviors, but not a syndrome. Behavioral Ecology. 20, 124-130.
Snekser JL & Itzkowitz M. 2009. Sex differences in retrieval behavior by the biparental convict cichlid. Ethology. 115, 457-464.
Gumm JM, Snekser JL, Leese JM, Little KP, Leiser JK, Imhoff VE, Westrick B & Itzkowitz, M. 2011. Management of interactions between endangered species using habitat restoration. Biological Conservation. 144, 2171-2176.
Kiesel A, Snekser JL, Ruhl N & McRobert SP. 2012. Behavioural syndromes and shoaling: connections between aggression, boldness and social behaviour in three different Danios. Behaviour. 149, 1155-1175.
Stephen Tettelbach, Ph.D.
The research that my students and I do seeks to better understand how and why marine populations vary in a changing environment; in turn, we have applied our findings toward the development and improvement of management and culture strategies for commercially important shellfish species. In particular, as part of our bay scallop restoration efforts in eastern Long Island waters, we have worked to develop and improve techniques for planting bay scallops and enhancing their survival, growth and reproductive success. This work has contributed significantly to increases in larval recruitment and has helped rebuild population sizes/densities and the commercial scallop fishery of New York. We do a great deal of Scuba diving and other fieldwork to monitor populations and conduct manipulative experiments; in addition, we have documented new discoveries about the basic biology and ecology of several marine species. Current research projects include: restoration of Peconic bay scallop populations and fisheries; habitat utilization by juvenile bay scallops; age, growth and initial reproductive maturity of the channeled whelk; predation of planted bay scallops by channeled whelk; locomotory behavior of adult hard clams.
Tettelbach, S.T., K. Tetrault & J. Carroll. in press. Efficacy of Netminder® silicone release coating for biofouling reduction in bay scallop grow-out and comparative effects on scallop survival, growth and reproduction. Aquaculture Research. Article first published online: 11 JUL 2012 DOI:10.1111/j.1365-2109.2012.03220.x
Tettelbach S.T., B.J. Peterson, J.M. Carroll, S.W.T. Hughes, D.M. Bonal, A.J. Weinstock, J.R. Europe, B.T. Furman & C.F. Smith. 2013. Priming the larval pump: resurgence of bay scallop recruitment following initiation of intensive restoration efforts. Marine Ecology Progress Series 478:153-172.
Carroll, J.M., B.T. Furman, S.T. Tettelbach, B.J. Peterson. 2012. Balancing the edge effects budget: bay scallop settlement and loss along a seagrass edge. Ecology 93:1637–1647.
Tettelbach, S.T., D. Barnes, J. Aldred, G. Rivara, D. Bonal, A. Weinstock, C. Fitzsimons-Diaz, J. Thiel, M.C. Cammarota, A. Stark, K. Wejnert, R. Ames, J. Carroll. 2011. Utility of high density plantings in bay scallop, Argopecten irradians irradians, restoration. Aquaculture International. 19(4):715-739.
Carroll, J. M., B. J. Peterson, D. Bonal, A. Weinstock, C. F. Smith and S. T. Tettelbach. 2010. Comparative survival of bay scallops in eelgrass and the introduced alga, Codium fragile, in a New York estuary. Marine Biology 157:249–259.