Collaborative Research at Skidmore: Biology

Collaborative Research (continued)

Skidmore students and their professors have worked together on numerous research projects. This kind of high-level scholarship does more than enhances a student's understanding in a given disipline; the practical, hands-on experience and "real-world" accomplishment also instill a sense of confidence that will benefit a graduate in any career. Projects from recent years appear below, arranged by academic area.

Biology

Project: The role of Capsule Production in the Symbiotic Colonization of Squid by Vibrio fischeri
Participants: Visiting Assistant Professor Pat M. Fidopiastis and Choai H. Wong '04
Plan: The associate between the luminous bacterium Vibrio fischeri and the squid Euprymna scolopes is a model for understanding how beneficial bacteria interact with their host. In this associate, V. fischeri colonizes the squid and is provided nutrients in exchange for light, which the squid uses for its nocturnal activities. The associate is highly specific, and only cells of V. fischeri are able to colonize the squid. As a defense against colonization, the squid possesses macrophage-like cells, similar to those seen in the mammalian immune system, that appear to destroy invading bacteria. However, V. fischeri cells are still able to colonize. Recently, we discovered that V. fischeri produces a capsule that may allow it to avoid destruction by the squid macrophages and colonize the squid.

Project: Spectral Properties of Circadian Clock Responses to Light Stimuli
Participants: Professor Bernard Possidente and Bond Caldaro '04
Plan: Daily rhythms in biological functions (e.g. sleep-wake cycle) are generated and regulated by an internal biological clock. Mammals, including humans, have evolved a central "circadian" (daily) clock in the hypothalamus of the brain just above the point where the optic nerves from both eyes meet. Circadian rhythms generated in the brain need only be synchronized by the external photoperiod. This is accomplished through retinal photoreceptors and central projections that are anatomically and functionally distinct from the visual system.

Project: Establishment of a Protoplast Cycle in the Unicellular Green Alga, Closterium acerosum
Participants: Professor David Domozych and Rachel A. Roberts '04
Plan: This project will define the protocols for obtaining protoplasts from the unicellular green alga Closterium acerosum. This organism is an important tool in plant cell research because of its large size and distinctive endomembrane and cytoskeletal systems. Likewise, it lends itself well to experimental manipulation and preparations for advanced light and electron microscopy. In this project, we will determine the precise conditions for inducing and subsequently culturing protoplasts. This will include defining enzymatic conditions, osmoticum levels and physical techniques that will optimize protoplast production. Similarly, we will attempt to complete the protoplast cycle by inducing morphogenesis back to the walled state. During this study, we will also monitor the effects of protoplast induction on secretion, the endomembrane system and cytoskeletal system. This study will entail use of cryofixation techniques, transmission electron microscopy and fluorescence light microscopy. This project will lay the groundwork for future studies in microinjection of specific tracing agents and molecular probes in understanding basic plant cell development.

Project: Female Mating Fidelity and the Avoidance of Inbreeding in a Dimorphic Warbler, the Common Yellowthroat (Geothlypis trichas)
Participants: Assistant Professor Corey R. Freeman-Gallant and Elizabeth M. Johnson '02
Plan: The Common Yellowthroat (Geothylpis trichas), a socially monogamous species abundant across much of North America, will be studied to assess the degree of female mating fidelity using molecular DNA techniques and to determine whether females copulate at random with respect to their similarity to potential sires. The importance of male plumage and health to female mating patterns will also be assessed.

Project: Rat Model for Androgenic Anabolic Steroid Abuse
Participants: Professor Bernie Possidente, Susan Kur '02 and Felicia Gomez '02
Plan: The focus of this project will be to study the effects of high, prolonged doses of steroid hormones, especially regarding potential effects on behavior and brain function. A rat animal model will be used to investigate effects of high doses of several commonly abused steroids on the level and circadian (daily) timing of wheel-running activity, as circadian rhythms, particularly sleep, are typically disrupted in psychiatric disorders similar to those associated with steroid abuse.

Project: Modification and Processing of Vitellogenin in Zebrafish Eggs
Participants: Professor Elaine Rubenstein and R. Carlin Walsh '01
Plan: Yolk proteins are synthesized outside of the ovary, transported through the blood, and then taken up by developing eggs within the ovary. These yolk proteins provide critical nutrients and building blocks to nourish and support embryonic development. In the zebrafish Danio rerio, our preliminary studies suggest that the principal yolk protein, vitellogenin, is biochemically modified and processed after the egg takes it up, but before the egg is fertilized. We intend to characterize the step-by-step changes in size and polypeptide composition that occur in the egg before ovulation which prepare vitellogenin to serve its embryonic functions.

Project: Localization and Function of the Cytomotile Proteins, Profilin and Myosin, in Cytoplasmic Streaming in Plants
Participants: Professor David Domozych and Brian Stevens, '00
Plan: The cascade of events created in cytomotility in plant cells requires numerous proteins. These proteins act precisely in regulating particular events associated in moving cytoplasmic elements across cytomotile cables in the cell, i.e., cytoplasmic streaming. Streaming is a necessary event in mixing nutrients in plant cells and, more importantly, directing particular compartments to specific destinations in the cell. In this project, we will attempt to locate and analyze the role of two cytomotile proteins, myosin and profilin, in the cytoplasmic streaming process in the green plant Closterium. These two proteins have been well characterized in animals, but little if anything is known about them in plants. In this project, we will mass-culture protoplasts of Closterium to create a better biochemical system for protein isolation. Second, we will isolate particular secretory elements such as Golgi elements and secretory vesicles using density gradient centrifugation. These are the elements that are moving in the cytoplasmic streaming network in Closterium. Next, we will extract myosin and profilin from the protoplasts and ultimately determine their location using immunoflourescence (light microscopy) and immunogold (electron microscopy) protocols. This project should provide significant fundamental information about how secretory elements move through the cell to reach sites on the cell membrane.

Project: A Search for Zymomonas mobilis in Apple Orchards in Saratoga County
Participants: Professor Chris Eddy and Keri L. Berka '00
Plan: Zymomonas mobilis is a Gram negative bacterium capable of producing ethanol from glucose more efficiently than yeast. Research on Z. mobilis has focused on finding or developing new strains that are better suited for industrial fermentation processes. The goal of this project is to determine if Z. mobilis can be isolated from apple orchards in Saratoga County, New York. Z. mobilis has been isolated from spoiled cider in Europe, and fermenting palm sap in tropical countries. We are developing methods to select for preferential growth of Z. mobilis and prevent growth of other bacteria and fungi that are present in cider, apples, and composted waste from nearby apple orchards. We will test our methods by adding known numbers of cells to each potential source and determining the minimum number of cells required to be isolated. Any new Z. mobilis strains isolated from samples not inoculated with the laboratory strain will be characterized and compared to strains used for ethanol production.

Project: Ecology, Management and Restoration of Native Plant Communities on Glacial Lake Albany Sand Deposit Outwash: Maintaining and Enhancing the Habitat of the Federally Endangered Karner Blue Butterfly, Lycaeides melissa samuelis
Participants: Associate Professor Monica Raveret Richter and Ava Tanny, '01
Plan: The Karner blue butterfly inhabits disturbed openings containing wild blue lupine, the sole host plant for its larvae (Dirig 1994), and nectar plants. Lupine is an early successional component of glacial Lake Albany sand outwash communities. Development, habitat fragmentation and fire suppression have led to the decline of lupine, butterflies, and other components of this community. Essential to halting this decline is characterization and maintenance of healthy patches of suitable butterfly habitat. We will investigate and characterize the relationship between the status of Karner blue food and nectar plant populations and aspects of the surrounding biotic and abiotic community. This information, combined with landscape analysis of aerial photos, can be used to promote successful maintenance and regeneration of Karner blue butterfly habitat in the Wilton Wildlife Preserve and Park.

Project: Genetic Population Structure in Savannah Sparrows (Passerculus sandwichensis) at Small Geographic Scales
Participants: Assistant Professor Corey R. Freeman-Gallant, David Vogel '99, and Kate Thomas '99
Plan: It is the goal of the collaborative project to allow Skidmore students to bridge the gap between subdisciplines and consider how molecular DNA techniques can be used to investigate long-standing issues in evolutionary biology. The team will propose to assay variation at neutral genetic loci to quantify the proportion of individuals exchanged between pairs of Savannah sparrow populations. Recent advances in molecular DNA technology combined with population genetic theory will enable the participants to link genetic differentiation to the magnitude and pattern of dispersal among sparrow populations.

Project: Is there a Circadian Rhythm for Fertility in Fruit Flies?
Participants: Professor Bernard Possidente and Mackenzie Evangelist '98
Plan: Circadian (daily) rhythms are generated by an internal biological clock mechanism. Fruit flies have been the leading model organism for investigating the genetic and molecular basis of biological clock function. The researchers are extending the fruit fly model to investigate the circadian regulation of complex behavior by characterizing a daily rhythm for mating and courtship behavior. Prior research has already established circadian clock regulation of mating behavior with a peak mating time that corresponds to six hours after sunrise. The proposed research is designed to determine whether the number of offspring produced depends on the time of day that mating occurs.

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