ßßß Northeast
District Convention

Saturday
April 15, 2000

at

Eastern Connecticut State University
Willimantic, Connecticut


2000 ßßß Northeast District Convention

Convention Timetable

Saturday, April 15, 2000
Eastern Connecticut State University

9:00Check-in Smith Library Community Room
Registration $10, Dinner Tickets $15
Refreshments
Poster Preparations: Goddard Hall Lobby
Slides/PowerPoint Check: Library Community Room, Goddard Hall Room 100
10:00 Welcome: Dr. Carmen Cid, advisor Eta Omega Chapter ßßß
Dr. Dimitrios Pachis, Vice-President for Academic Affairs, ECSU
Dr. Terry Graham, Northeast Region District 1 Director
Keynote Address: Dr. David Pimentel, Cornell University
11:00 Oral Presentation Session 1a
Molecules, Cells, Physiology
Library Community Room
Dr. Yaw Nsiah, Convener
Oral Presentation Session 2a
Organisms, Populations, Environment
Goddard 100
Dr. Gloria Colurso, Convener
12:00Lunch at Hurley Hall Cafeteria--Complimentary Ticket Required
1:00Oral Presentation Session 1b
Molecules, Cells, Physiology
Library Community Room
Dr. Mike Adams, Convener
Oral Presentation Session 2b
Organisms, Populations, Environment
Goddard Hall Room 100
Dr. Elizabeth Cowles, Convener
2:00Poster Presentation Session 1
Molecules, Cells, Physiology
Goddard Hall Lobby
Poster Presentation Session 2
Organisms, Populations, Environment
Goddard Hall Lobby
3:30Judges Meeting in Goddard Hall Room 104
4:00Awards Banquet, Library Community Room, Terry Graham, Presiding
Main Entree Choices: Rosemary Chicken and Pasta Primavera


2000 ßßß Northeast District Convention

Registration, Refreshments

Keynote Address

9:00-11:00 Library Community Room

9:00 Registration

Upon $10 registration, you should receive a copy of this program, the complimentary lunch ticket, any banquet ticket you ordered ($15), and so on. A complimentary assortment of pastries and beverages will be provided. You are invited to mount your poster in Goddard Hall Lobby or to check your slides or the computer facilities for oral presentations in the Library Community Room or Goddard Hall Room 100

10:00 Welcoming Remarks

Dr. Carmen Cid, advisor Eta Omega Chapter ßßß
Dr. Dimitrios Pachis, Vice-President for Academic Affairs, ECSU
Dr. Terry Graham, Northeast Region District 1 Director

Keynote Address

Ecology of Increasing Disease:
Population and Enviromental Pollution

Dr. David Pimentel

Biographical Sketch

David Pimentel is a professor of insect ecology and agricultural science at Cornell University, Ithaca, NY 14853-0901. He received his BS degree at the University of Massachusetts and his Ph.D. degree at Cornell University. His research spans the fields of basic population ecology, ecological and economic aspects of pest control, biological control, biotechnology, sustainable agriculture, land and water conservation, natural resource management, and environmental policy. Dr. Pimentel has published more than 490 scientific papers and 20 books and has served on many national and government committees including the National Academy of Sciences; President's Science Advisory Council; U.S. Department of Agriculture; U.S. Department of Energy; U.S. Department of Health, Education and Welfare; Office of Technology Assessment of the U.S. Congress; and the U.S. State Department.


2000 ßßß Northeast District Convention

Oral Presentation Session 1a

Molecules, Cells, Physiology

11:00-12:00 Library Community Room

Dr. Yaw Nsiah, Convener

11:00 - 11:20

Regulation of the cardiac action potential by Angiotensin II

Hulda Michel and Cheryl Watson (860-832-2649 watsonc@ccsu.edu)
Biological Sciences Department, Central Connecticut State University, New Britain, CT 06050

Cardiac arrhythmias are a major cause of death in heart failure patients. Coincidentally, there is also an increase in the amount of circulating Angiotensin II. Intracellularly, one of the effects of Angiotensin II is the activation of cytoplasmic tyrosine kinases. Previous research indicates that tyrosine phosphorylation can prolong sodium current. It has also been shown to affect potassium current. Electrocardiograms of rats treated with Angiotensin II show a prolonged action potential, and a longer repolarization period, which proved to be arrhythmogenic. Our goal was to demonstrate, using immunoprecipitation and Western blotting, that Angiotensin II activates tyrosine kinase in the myocardium and causes phosphorylation of cardiac ion channels.


11:20-11:40

The effects of tyrosine kinase on the cardiac action potential

Izabela Krakowiak and Cheryl Watson (860-832-2649 watsonc@ccsu.edu)
Biological Sciences Department, Central Connecticut State University, New Britain, CT 06050

Heart failure or hypertrophy affects many Americans. During hypertrophy there is an increase in intracellular tyrosine kinase, which increases cell growth and phosphorylates intracellular proteins. Tyrosine kinase can phosphorylate many proteins, including membrane proteins such as ion channels, which in turn can affect ion flow. Since ion currents are the basis of the cardiac action potential, phosphorylated channels may affect cardiac rhythm. The purpose of this project was to determine if non-receptor tyrosine kinases affect cardiac rhythm. We tested this hypothesis by administering two drugs, Tyrphostin B44, a tyrosine kinase inhibitor and vanadate, which unmasks native tyrosine kinase activity. The effect of both drugs on the cardiac action potential (Q-T interval) was measured continuously on an electrocardiogram. The Q-T interval and the heart rate were both altered by vanadate, and the effects reversed by Tyrphostin B44. Vanadate also caused a variety of atrial and ventricular arrythmias.


11:40-12:00

Interferon consensus sequence binding protein expression in dendritic cells

Evangelos Pefanis (718-405-3383 epefanis@manhattan.student.edu) and Thomas H. Moran
Biology Department, Manhattan College/College of Mount St. Vincent, Riverdale, NY 10471 and Microbiology Department, Mount Sinai School of Medicine, New York, NY 10029

The new consensus among immunologists is that the dendritic cell, and not the macrophage, is the primary initiator of the immune response. Dendritic cells are potent antigen presenting cells capable of inducing a TH1 immune response, which is necessary for the clearing of viral infections. Infection of antigen presenting cells by intact viral particles induces the expression of several cytokines, most notably interleukin-12, which promotes the maturation of nave CD4+ T lymphocytes to TH1 lymphocytes. It has previously been shown that the expression of interleukin-12 is dependent upon the presence of the interferon consensus sequence binding protein (ICSBP), a transcription factor belonging to the interferon regulatory factor (IRF) family of proteins. We have shown here that ICSBP expression is upregulated upon in vitro lipopolysaccharide (LPS) and interferon-g (IFNg) stimulation of dendritic cells.


2000 ßßß Northeast District Convention

Oral Presentation Session 1b

Molecules, Cells, Physiology

1:00-2:20 Library Community Room

Dr. Mike Adams, Convener

1:00-1:20

Selective partitioning of neural cell adhesion molecules (N-CAM) isoforms with Triton X-100

Vina Cruz (718-405-3389 jhaley@cmsv.edu)
Biology Department, Manhattan College/College of Mount St. Vincent, Riverdale, NY 10471

Astrocytes play a critical role in neurobiology in several aspects: in the balance of K+ to sustain the neuronal environment, in brain development, in neurotransmission, and in formation of the blood-brain barrier. Astrocytes contain a cell adhesion molecule, N-CAM, which participates in cell-cell recognition and interaction. N-CAM, a cell surface glycoprotein, participates, in part, in the aforementioned brain functions of astrocytes in the CNS. During brain injury and other neurological diseases, reactive astrocytes produce glial scars, which result in gliosis and these cells disrupt CNS neurons from regenerating. This astrocytic gliosis inhibits the axon from penetrating the glial scars. Recently, N-CAMs, in culture, have been shown to inhibit the proliferation of astrocytes and perhaps this may have clinical ramifications. In this research, N-CAM, from astrocyte cultures, selectively portioned into a Triton insoluble, cytoskeletal fraction (TI) and into a Triton soluble fraction (TS) were first isolated via centrifugation. Next, examination of Western blots of two-dimensional polyacrylamide gels showed that the lower molecular weight isoform N-CAM (~120Kd) partitioned into the TI whereas two higher molecular weight isoform N-CAMs (~160 and 200 Kd) into the TS. Therefore, inhibition of astrocyte proliferation by N-CAM may be associated with the cytoskeleton for anchorage.


1:20-1:40

Sulindac inhibits cell growth by inducing apoptosis in human endometrial carcinoma cells after proliferation with 17-ß estradiol

Jeffrey Ranaudo, Salvatore Coscia (914-323-5120 betticaa@mville.edu)
Biology Department, Manhattanville College, Purchase, NY 10577

Sulindac sulfoxide (Clinoril), one of the many nonsteroidal anti-inflammatory drugs (NSAIDs), has shown chemopreventive and tumor regressive activities in several human cancers including breast, colon, prostate, and lung. Sulindac sulfoxide, the inactive prodrug, reduces to the active sulfide in vivo or oxidizes to sulindac sulfone, which lacks prostaglandin synthetase inhibitory activity. In addition to its analgesic and antipyretic properties in the treatment of arthritis, sulindac has inhibited the growth of a variety of tumor cell lines by affecting proliferation, differentiation, and apoptosis. This study examines the effects of sulindac sulfoxide on the proliferation and apoptosis of the human endometrial carcinoma cell line RL95-2. The growth-inhibitory responses of these cells to sulindac are time and concentration-dependent. Treatment of RL95-2 cells after proliferative doses of 17-ß estradiol with 600uM sulindac for 48-72 hours showed morphologic changes, inhibition of growth rate, and other anti-proliferative effects. In the absence of estradiol, 400 uM sulindac was sufficient to inhibit the growth rate of RL95-2 over the same time period. In situ detection of DNA fragmentation using the TUNEL method and confirmation by apoptotic cell morphology provides preliminary evidence of apoptotic mechanisms for the observed inhibitory growth rate.


1:40-2:00

Recovery of recombinant influenza B viruses from cDNA

Dmitriy Zamarin (718-405-3383 heyimdz@hotmail.com), Karl Anderson, Jason Paragas and Peter Palese
Biology Department , Manhattan College/College of Mount St. Vincent, Riverdale, NY 10471 and Microbiology Department, Mount Sinai School of Medicine, New York, NY 10029

Recent advances in virology and understanding of structure and replication of the negative-strand RNA viruses have led to development of new methods of manipulation of viral genomes, such as rescue of synthetic genes into influenza viruses. Currently, we are working on the development of a system that would allow the rescue of infectious influenza B viruses entirely from cloned cDNA. The complete genome of B/Yamagata/73 influenza virus was cloned into plasmids between the human RNA polymerase I promoter and hepatitis delta virus ribozyme sequence. Transfection of these plasmids into human embryonic kidney cells (293T) along with vectors expressing viral polymerase proteins results in generation in vivo of viral ribonucleoprotein (RNP) complexes, which upon expression form viral particles. While no functional viruses were detected after transfection, we were able to show that the generated viral particles were capable of packaging and delivering a foreign reporter gene (CAT) to other cells. This plasmid-based reverse genetics technique will facilitate the study of viral structure and replication, and could lead to development of new vaccines and gene therapy vectors.


2:00-2:20

Characterization of human EYA2, a homolog of the Drosophila eyes-absent gene

Christina A. Doyle and Brian E. Fee (718-862-7414 bfee@manhattan.edu)
Biology Department, Manhattan College/College of Mount St. Vincent, Riverdale, NY 10471

The Drosophila eyes-absent (eya) gene is required in the development of the compound eye: without it, progenitor cells in the eye imaginal disc undergo programmed cell death (apoptosis), resulting in eyeless flies. Homologs have been found in organisms from plants to vertebrates. In humans, a family of four homologs, EYA1-4, has been isolated. If EYA has a functional homology to Drosophila eya, it may prevent cell death, and therefore, could lead to the uncontrolled cell growth seen in cancer. Our previous research of EYA2 in human neuroblastoma cells identified four mRNA transcripts differing only at the 5' end, one of which contained a start codon fifteen bases upstream of the accepted start codon. To determine the actual 5' end of the EYA2 mRNA from a nontumorigenic tissue, we isolated the mRNA from a human eye. The 5' end of the EYA2 cDNA was sequenced and found to contain the upstream start codon stated above, indicating that the human EYA2 protein sequence is five amino acids longer than previously published.


2000 ßßß Northeast District Convention

Oral Presentation Session 2a

Organisms, Populations, Environment

11:00-12:00 Goddard Hall Room 100

Dr. Gloria Colurso, Convener

11:00-11:20

Manganese Toxicity In Human Fibroblast Cells

Sarah Blair (860-423-1506 blairsa@hermes.ecsu.ctstateu.edu)
Biology Department, Eastern Connecticut State University, Willimantic, CT 06226

Manganese (Mn) toxicity causes a number of severe, pathological effects including encephalopathy and parkinsonism; however the effect of Mn on cell growth is poorly documented. The purpose of this research was to study human fibroblast proliferation and morphology in the presence of Mn. The human fibroblasts proliferated in the absence of Mn, but 25 and 50 ppm concentrations of Mn distinctly limited growth in a dose-dependent manner. The lowest concentration of Mn used (7.5 ppm) however, still inhibited cell proliferation. Magnesium, but not calcium, counteracted the inhibitory effects of Mn. Mn exposure caused cellular blebbing and a granular appearance in the fibroblast cytoplasm. The effects were more pronounced at higher concentrations of Manganese. Late passage fibroblast cells were much more susceptible than early passage cells to Mn exposure showing slower proliferation rates as well as drastic cytoplasmic blebbing and a granular cytoplasm. The relevance of this work is important, not only in older individuals, but in rapidly growing children. It is suggested that the brain slowly accumulates manganese and toxic effects occur after long-term exposure. Controlling Mn toxicity can have great implications for reducing the neurological damage seen in liver function-impaired people.


11:20-11:40

The effect of the tunicate, Molgula manhattensis, on marine microbial growth

Diane Craft and Michael Judge (718-405-3391 mjudge@manhattan.edu)
Biology Department, Manhattan College/College of Mount St. Vincent, Riverdale, NY 10471

Many marine organisms, including tunicates, possess biologically active compounds that function against microbes and other organisms. These compounds may play a vital role in survival because they are metabolically expensive, structurally complex, and found in high concentrations. The effect of the temperate subtidal tunicate, Molgula manhattensis, on co-occuring bacteria was determined by zones of inhibition on a disk assay experiment. Water samples and tunicate specimens were collected from a marina (Bronx, NY) during fall 1999. One bacterial species was isolated and identified using various growth media and the API 20E system. The tunicates were frozen, divided into visceral and tunic components, and homogenized separately via Waring blender. Utilizing five different treatments (homogenized viscera, homogenized tunic, 3.0 m filtered sea water, sterile sea water, and distilled water), the disk assay experiment revealed no differences among the zones of inhibition (all means = 0 mm). Results suggest that M. manhattensis did not exhibit any pronounced anti-microbial activity towards this species. Thus, M. manhattensis has not developed effective defenses against all naturally co-occurring bacteria.


11:40-12:00

Maize root adaptation to conditions of low inorganic phosphate in soil

Patricia Dranchak (607-378-5448 pdranchak@elmira.edu)
Division of Mathematics & Natural Sciences, Elmira College, Elmira, NY 14901

Maize excretes the enzyme acid phosphatase (ACP) from its roots into its environment to cleave the phosphate group off both organic and inorganic compounds for easy uptake by the plant. It has been observed that the excretion of ACP can be stimulated in phosphate-depleted environments. Through the use of enzyme activity assays and isoelectric focusing we determined that there is an increase in ACP production and excretion in plants grown in phosphate depleted environments compared to plants grown in phosphate repleted environments. We then explored the structure of ACP, hypothesizing that it contains a phosphate group. Preliminary studies indicate that ACP probably does contain a phosphate group which may function as its main receptor site.


2000 ßßß Northeast District Convention

Oral Presentation Session 2b

Organisms, Populations, Environment

1:00-2:00 Goddard Hall Room 100

Dr. Elizabeth Cowles, Convener

1:00-1:20

An investigation of observed morphological deformities in the bullfrog, Rana catesbeiana, within Connecticut

Heather Fried (860-487-3822 fried@neca.com)
Biology Department, Eastern Connecticut State University, Willimantic, CT 06268

Isolated instances of morphological deformities in amphibians have been reported since the turn of the twentieth century, but the rise in the number of reports nationally over the last five years has sparked concern within the scientific community that anthropomorphic factors maybe be to blame. Concern over this phenomenon was heightened in Connecticut when deformed green frogs (Rana clamitans) were found in Sterling, Connecticut during the fall of 1997. In an effort to determine the incidence of morphological deformities in Connecticut, anuran collections were made during the summer of 1998 at twelve wetlands statewide. Collection results indicate that deformities were isolated to bullfrogs (Rana catesbeiana) found in Porter Pond, Sterling, Connecticut. Deformities predominantly affected the hind limbs of juveniles. Many limb deformities in amphibians have been attributed to parasites, however, the types of deformities observed at Porter Pond may be the result of intraspecific and interspecific predation.


1:20-1:40

Developmental Analysis of Limb Deformities in Amphibians

Louise Hecker (607-431-6989 heckerl@hartwick.edu) and Doug Hamilton
Biology Department, Hartwick College, Oneonta, NY 13820

I have tested the idea that mechanical perturbation, via surgical limb rotations, is sufficient to induce malformations in amphibians including supernumerary limbs. Currently, four leading hypotheses have emerged, each revolving around a different central idea, which explains the occurrence of deformities in the wild: parasites, retinoids, ultraviolet irradiation, and attempted predation/cannibalism. I used microsurgery to produce limb deformities in developing frog tadpoles. I compared them to deformed amphibians found in the wild. I identified the types of deformities that were found. In particular, I looked for a specific type of deformity of the proximal-distal limb axis, that is thought to be diagnostic of retinoids, called a "bony triangle." A bony triangle is characterized by its triangular shape in which the proximal and distal ends of the bone are adjacent. The bone itself is bent in which the midpoint of the bone forms the vertex of the triangle. Based on my results, I concluded that mechanical perturbation is adequate to cause limb malformations, including outgrowth of supernumerary limbs and bony triangles. Furthermore, the range of morphologies produced through microsurgery is indistinguishable from the range of morphologies found in the wild. Parasite cysts are thought to cause limb deformities via mechanical perturbation of developing limb buds. Thus, these results provide strong support for the parasite hypothesis.


1:40-2:00

The unusual chondriome of Chlamydomonas acidophila

Pascale Rabbah and Ioanna Visviki (718-405-3482 avisviki@aol.com)
Biology Department, Manhattan College/College of Mount St. Vincent, Riverdale, NY 10471

Chlamydomonas acidophila is a unicellular, flagellated green alga of the order Volvocales, family Chlamydomonadaceae. It has been isolated from lakes and acidic bogs with pH as low as 2. The ultrastructure of this chlorophyte is unique, due to the large size and position of its mitochondria. The mitochondrial volumes of other Chlamydomonas species vary between 1-3% and the mitochondria are located directly below the cell membrane. The mitochondrial volume of C. acidophila varies between 4-6% and the mitochondria are located below the chloroplast. Examination of the chondriome, quantified by morphometric analysis, indicates that it is a dynamic cellular component, changing continuously during the light cycle via fragmentation, fusion and autolysis. At the onset of the light cycle (L0-L4) small mitochondria predominate. At L6-L8 the average number of mitochondrial segments decreases significantly and giant mitochondria appear via fusion, bearing clear foci and disorganized cristae. During L9-L12 the average number of mitochondrial segments increases significantly and small mitochondria are prevalent. The significance of the results is discussed and comparisons are made with other Chlamydomonas congeners.


2000 ßßß Northeast District Convention

Poster Presentation Session 1

Molecules, Cells, Physiology

2:20-3:30 Goddard Hall Lobby

Poster 1A

An investigation into the role of kinesin-II of sea urchins

Fay Dufort (508-286-5293 fdufort@tempest.wheatonma.edu)
Biology Department, Wheaton College, Norton, MA 02766

Cilia are beating, hair-like extensions on the surface of the cell. They are useful to a cell because they allow the movement of a cell or an aggregation of cells, such as in a blastula-stage embryo, through a liquid. Cilia may sway or swing to propel cells forward or propel fluid over a surface. In this research project we examined sea urchin blastulae (40-60 hour embryos) in the process of ciliogenesis. Each cilium contains independent machinery for movement. Employing immunofluorescent techniques, we labeled the cilium's microtubule sub-units (tubulin), the motor protein kinesin-II, and the cell's DNA. We localized kinesin-II using fluorescence microscopy to test the hypothesis that kinesin-II performs a role in ciliogenesis. It is hypothesized that kinesin-II illustrates the process of ciliogenesis to have two distinct stages: the first not requiring kinesin-II, the second recruiting kinesin-II. Further investigation is needed to understand the role of motor proteins in cilia formation.


Poster 1B

The angiogenic effects of 9- and 13-hydroxyoctadecadienoic acid on in vivo as well as in vitro assays

Jean Campbell (508-286-3948 jcampbel@wheatonma.edu) Biology Department, Wheaton College, Norton, MA 02766

Angiogenesis is the formation of new blood vessels from a preexisting vasculature network. Angiogenesis plays a major role in many pathological conditions, such as tumor growth, chronic inflammation, wound repair and the menstrual cycle. The angiogenic effects of 9- and 13-hydroxyoctadecadienoic acid (HODE) were investigated in both in vivo as well as in vitro models. 13-HODE has been clearly shown to have an angiogenic effect on the chick chorioallantoic membrane. On a more recent note, both 9- and 13-HODE have also been shown to stimulate growth in bovine endothelial cells. These present studies have shown 9-HODE to have a similar angiogenic effect to that of 13-HODE. Endothelial cell migration, which is as important a process as proliferation, was stimulated by 9- and 13-HODE (in comparison to ethanol controls). In addition, the ultimate test for in vitro studies of angiogenesis, tube formation, will be continued to be investigated in the future. Using both the in vivo assay (CAM) and the three in vitro assays, the angiogenic effects of 9- and 13-HODE may be clearly elucidated.


Poster 1C

Both preheating and deflagellation offer protection against heat stress in Chlamydomonas

Denise Ramoutar (860-456-3031 ramoutard@hermes.ecsu.ctstateu.edu) and Mike Adams
Biology Department, Eastern Connecticut State University, Willimantic, CT 06226

Organisms respond to heat shock by producing a specific set of heat shock proteins (hsp) including hsp70, believed to aid in the correct folding and transport of newly made proteins. It has been previously shown that when Chlamydomonas, normally grown at 20°C, are incubated at 35°C for one hour they exhibit 100% survival, and additional hsp70 is produced. Cells incubated at 45°C show minimal survival, depending on the length of exposure and speed of cooling back down to room temperature. The standard used in these experiments was to heat the cells at 45°C for 10 minutes and then cool to room temperature on ice, which gives an average survival rate of 0.2%. To test whether the additional hsp70 produced at 35°C could help protect against the effects of high temperatures, cells were incubated at 35°C for 1 hour and then treated at 45°C. The survival jumped to 15.8%, showing a 300-fold increase in survival compared to without preheating. Since earlier work had shown that deflagellation also causes increased hsp70 production, we looked at high temperature survival following deflagellation. This gave a survival rate of 4.5%: lower than the preheated cells, but still 90-fold greater than untreated cells. These values are consistent with previous work, which has shown that the quantity of hsp70 mRNA produced following deflagellation was less than that made after heat shock. These results suggest that the protective function of hsp70 is independent of the reason it was synthesized.


Poster 1D

The effect of corticosterone treatment on the aggressive behavior of a dominant male lizard, Anolis carolinensis

Denise Campisi (860-456-9325 campisid@hermes.ecsu.ctstateu.edu)
Biology Department, Eastern Connecticut State University, Willimantic, CT 06226

Hormonal research concerning the social behavior of a variety of organisms has uncovered a relationship between low levels of aggressive behavior and corticosterone. The purpose of this study was to test whether corticosterone would inhibit the aggressive behavior of a dominant male Anolis carolinensis lizard. Two sets of equal sized males were randomly assigned as the experimental or control pair. Each pair of lizards was placed together with a female lizard for twenty-minute intervals until the dominant member of each pair was established. Once dominance had been established, the experimental dominant received a subcutaneous pellet designed to deliver corticosterone at a constant rate for twenty-one days. The subordinate of the experimental pair along with both members of the control pair received subcutaneous placebo implants. Both pairs were again observed for twenty-minute intervals over a three-week period in the same manner as previously described. The corticosterone treated dominant exhibited aggressive behavior significantly less than prior to receiving the pellet. Also, after receiving the placebo pellet, the experimental subordinate exhibited aggressive behavior significantly more often. The results also indicated that corticosterone caused body color to darken. Thus, this study showed that corticosterone inhibited aggressive behavior in a dominant male A. carolinensis lizard.


2000 ßßß Northeast District Convention

Poster Presentation Session 2

Organisms, Populations, Environment

2:00-3:30 Goddard Hall Lobby

Poster 2A

Experiments relating to the mutualistic interactions of Azteca ants and Cecropia trees

Lisa Baumgartner (860-465-2967 baumgartnerl@hermes.ecsu.ctstateu.edu) and Amy Pia
Biology Department, Eastern Connecticut State University, Willimantic, CT 06226

A prominent ant-plant mutualism is the Cecropia (tree) - Azteca (ant) interaction. The Azteca protect Cecropia from herbivores and from vines, while the tree provides the ants with shelter and nutrition through the production of glycogen-rich Mullerian bodies found on trichilla. We attempted to quantify three aspects of this interaction: 1) the relationship between herbivory damage and the size of the ant colony inhabiting the tree, 2) the rate of Mullerian body production in response to harvesting by the ants, and 3) the response of ants to vines attempting to utilize the Cecropia for support. Herbivory damage, relative to percent coverage, was found to be greatest on the tree with no ants. When a greater ant population was present, the trees had fewer holes in leaves. The trichilia which ants could forage on produced significantly more Mullerian bodies than the trichilia with Tanglefoot boundaries. The Azteca ants were able to recognize Mullerian bodies regardless of placement or number. The ants did not attempt to chew through dead vines. The results suggest that Cecropia regulates its production of Mullerian bodies in response to ant harvesting, the size of the ant colony is positively related to a reduction of herbivore damage, and the ants appear to be able to distinguish between live and dead vines.


Poster 2B

Aquatic home range areas and habitat use of Pseudemys rubriventris in southeastern Massachusetts

Michael Webber (508-929-8646 tgraham@worc.edu)
Biology Department, Worcester State College, Worcester, MA 01602

The home range areas, individual straight-line movements, and habitat use of Pseudemys rubriventris were investigated in a 52 ha pond in southeastern Massachusetts. Eleven adult red-bellied turtles (6 F, 5 M) were radio-tracked for a 14-week period from August to November 1999. Aquatic home range areas were calculated by the grid summation method. Male mean home range area was 16.36 ha (range = 14.90-17.78; SD = 1.26); male mean greatest home range length was 1247.83 m (range = 966.28-1399.44; SD = 183.11). Female mean home range area was 12.58 ha (range = 8.90-16.29; SD = 2.97); female mean greatest home range length was 988.49 m (range = 733.04-1274.49; SD = 245.06). Home range areas differed significantly between sexes but were not correlated with carapace length or body mass. Greatest home range length did not differ significantly between sexes. Daily aquatic straight-line movements averaged 117.94 m per day (SD = 25.62) for all animals. Male mean movement was 124.55 m/d (range = 89.86-157.04; SD = 28.88) and mean female movement was 109.66 m/d (range = 93.58-141.58; SD = 21.78). No significant differences existed between sexes. Activity was concentrated in open water/milfoil and floating bog mat habitats. Aquatic hibernacula were located within a 1600 m2 area between the forested shoreline and bog mat in the western portion of the pond.


Poster 2C

Wetland habitat use by non-migrant birds in eastern Connecticut: effects of vegetation on species composition

Heather Fried (860-487-3822 fried@neca.com), Susan Herrick, and Dan Ramos Biology Department, Eastern Connecticut State University, Willimantic, CT 06268

Wetlands are essential habitat for diverse assemblages of avian species year round, and provide protection and food throughout the winter. Species abundance and diversity has been found to be related to vegetation structure, productivity and the extent to which different species can successfully divide the habitat and food resources. In this study we surveyed wet meadow, marsh and forested sites within a local wetland, Eaton's Pond, in October 1999 to determine the extent to which vegetation form and structure affected the diversity and abundance of non-migratory birds. Results indicated that bird diversity, abundance and number of foraging guilds increased with an increase in the number of vegetation forms but were not strongly influenced by the actual vegetation height. Lack of research concerning the utilization of wetlands by non-migratory birds makes the results of this study important for future wetlands management.


Poster 2D

The effects of habitat modification on the aggression and dominance relationships of damselfish

Kelly McCurdy (860-465-4908 mccurdyk@hermes.ecsu.ctstateu.edu)
Biology Department, Eastern Connecticut State University, Willimantic, CT 06226

Damselfish are highly aggressive territorial herbivores that inhabit all waters of the world. Two Blue Devil damselfish, Pomacentrus coeruleus, and one Yellowtail damselfish, Pomacentrus violascens, were used in this experiment in order to investigate the effects of habitat modification on aggression and dominance. This was accomplished by placing the fish in a thirty-five gallon tank and recording the aggressive interactions. The fish determined to be dominant was then confined to one side of the tank to allow the subordinates to establish residency in the remaining area. In a second experiment, the location of coral within the tank was modified. Dominance did not change among the fish after either modification, however, aggression increased significantly. It has previously been shown that a new hierarchy may be established in less than one hour after a habitat modification. This may explain the significant increase in aggression that was portrayed. It has also been shown that social rank reversal is usually caused by relationships in relative physical strength of fish, in which dominants tend to lose energy by chasing other fish. Dominance reversal may not have occurred in this experiment because the dominant fish was larger and was able to overcome the two subordinates.


Poster 2E

The effect of brood parasitism on adult warbler feeding behavior

Susan Z. Herrick (860-423-2119 herricks@hermes.ecsu.ctstateu.edu)
Biology Department, Eastern Connecticut State University, Willimantic, CT 06226

The brood parasitic Brown-headed Cowbird (Molothrus ater) is recognized as a potential threat to the continued survival of many of its host species, including some songbirds of New England. Avian brood parasitism has its most obvious impact on host species' current reproductive success. However, the presence of a cowbird nestling in a nest may cause the host parents to increase their provisioning rate to the nestlings, thereby increasing reproductive costs of the host. Feeding rates of five species of migratory warblers were examined to determine if feeding visits to the nest per hour were influenced by the presence of cowbird nestlings. When differences in clutch size are accounted for, parasitized hosts show a significantly higher provisioning rate than unparasitized. Therefore, in addition to the normal reproductive costs associated with cowbird parasitism, such as loss of host eggs and increased nestling mortality, there are additional energetic costs associated with provisioning the surviving nestlings. Because reproductive effort and survivorship are generally inversely related, lifetime fitness of parasitized parents may be negatively affected through lowered survivorship.


Poster 2F

Storm water toxicity to Daphnia pulex is due to acid rain and copper interactions

Timothy Ferris (860-822-9563 aote_ct@yahoo.com)
Biology Department, Eastern Connecticut State University, Willimantic, CT 06226

Storm water discharge from industrial activities is frequently cited for its lethal effects on aquatic organisms. In the presence of acid rain, heavy metal contaminants, such as copper, zinc or lead, are released from industry-polluted soil and water. Free copper at a concentration of approximately 4 parts per billion is lethal to Daphnia pulex. Copper complexed with EDTA raises the LC50 and reduces the acute toxicity; however this effect is reversed by a pH decrease. This indicates that free, (not complexed) copper is necessary for lethality. Storm water discharge with a high Chemical Oxygen Demand (COD) has a higher LC50, suggesting that the copper is complexed. The presence of acid rain water dissociates the metal complexes, and subsequently raises the acute toxicity.