Journal of Biological Research, Vol. 10 (2009)

Microbial Community Analysis of Soils Associated with Cercocarpus ledifolius Stands on Mt. Charleston, Nevada.
SANDRA ARMAKOVITCH, Biology Department, Hartwick College.
Plant species affect soil formation, an understanding of which is important to climate change research and earthquake risk studies. This project is part of a 30+ year study on soil formation rates in and around sites occupied by the long-lived plant Curlleaf Mountain Mahogany (Cercocarpus ledifolius) in an arid ecosystem, Mt. Charleston, Nevada. The goal of this project is to assess the diversity of microorganisms inhabiting soil samples from four microhabitats: open interspaces between woody vegetation (i.e. C. ledifolius), isolated small adult trees, isolated large adult trees, and large adult surrounded by other trees. The microbial community was explored using community DNA extracted from soil samples. Investigations included screening for the presence of nitrogen fixing genes (nifH), ARDRA (Amplified Ribosomal DNA Restriction Analysis) comparisons of different sites and determination of community members using 16S rRNA gene sequencing. Advisor: Dr. Mary Allen.

An Evaluation of Wound Healing in Drosophila Larva with 100% Oxygen.
IAN AVENIA-TAPPER, Biology Department, Hartwick College. Studies have shown that the healing process is oxygen dependent. (P. C. Tomphach, 1997). The purpose of this experiment is to determine if increased oxygen leads to increased wound healing in a small experimental organism. Due to their similarities in the wound healing processes to humans, (Micheal J. Galko, 2004) and their short life cycle the model used will be Drosophila larva. This experiment will evaluate the effectiveness of 100% oxygen by examining the rates of puncture wound healing in Drosophila larva. A light microscope will be used to measure the size of the wounds on daily interval. The wounded larvae will be randomly assigned to three groups; control (exposed to room air), and three different treatment groups 100% oxygen for 30, 60, 90 minutes daily. Advisor: Dr. Laura Malloy.

 Decontamination of coliform bacteria from drinking water in villages of the hilltribes region of Northern Thailand.
KYLE BERTRAND, Biology Department, Hartwick College. Access to clean drinking water is a problem for millions of people worldwide. According to the UN World Water Development Report (2006), one billion people lack access to an improved water supply. One such area is the hill tribes region of northern Thailand. In the villages that comprise the hill tribes region, residents lack the ability and/or knowledge to purify their drinking water. A previous study found that the bacteria coliform was present in the drinking water at the three villages that were tested (Bateman, 1995). The presence of coliform in a water source is usually an indication that there are other pathogens present as well (NYS DOH, 2005). These pathogens can lead to serious illnesses, including growth stunting, in children 0-5 years old. This study developed an affordable, easy to use UV water purification system to eliminate coliform bacteria from the drinking water. By eliminating coliform bacteria from the drinking water, the overall health of villagers will improve. Advisor: Dr. Linda Swift.

Rearrangements of Tpl and the Osiris gene cluster induced by FLP/FRT recombination.
VICTORIA BRODERICK, Biology Department, Hartwick College. Drosophila melanogaster contains a uniquely dosage sensitive locus called Triplolethal (Tpl) which is both triplo- and haplo-lethal . Approximately half of the Tpl region is occupied by the Osiris gene family. These genes encode putative transmembrane proteins of unknown function. Due to the lack of point mutations causing haplo-lethality, the Osiris family collectively has been speculated to be responsible for the Tpl phenotype. We are determining the exact endpoints of the Tpl region by using FLP/FRT recombination to create DNA duplications and deletions within and near the Osiris gene family. We have completed both a deletion and a duplication spanning all twenty genes of Osiris, and genetically determined that Tpl specifically maps to these clustered genes. We are working on smaller DNA rearrangements to help determine more precisely the cause of the unique dosage sensitivity in this area Advisor: Dr. Douglas Dorer.

Modes of Transmission of the Polyomavirus Simian Virus
OLIVIA BURLEW, Biology Department, Hartwick College. In the 1950's and 1960's hundreds of millions of people worldwide were accidentally infected with the polyomavirus Simian Vacuolating Virus 40 (SV40) through tainted polio vaccines. SV40 is considered a low level oncogenic virus, and has not been linked to an increased cancer rate. The problem is that the virus is now turning up in rare tumors in people who were exposed as well as in people who never came into contact with the virus. The method by which SV40 is spread has never been proven. This project will test the hypothesis that the virus is spreading via sexual contact, excretions, and from mother to progeny. If the results correlate with the hypothesis then preventative measures can be taken to stop the spread of SV40 and perhaps cause a decline in the prevalence of these rare tumors. Advisors: Drs. Allen Crooker and Douglas Dorer.
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The effect of water pressure on respiratory parameters in exercising swimmers.
DEVON FULLER, Biology Department, Hartwick College. Swimming exercise presents some unique challenges to adjustments in ventilation because water pressure presents resistance to movements of the chest cavity. This may complicate respiratory adjustments to regulate pH that can occur during intense exercise. This study evaluates the hypothesis that the resistance of the water on a person's chest can reduce the depth of ventilation (tidal volume) and thereby cause a decrease in their pH. With Hartwick's IRB approval, eight subjects engage in 3 levels of exercise while submerged to the neck or while riding a float that elevates their chests out of the water. Exercise intensity is gauged by percent of maximum heart rate, a respirometer is used to measure respiratory rate and tidal volume and pH paper is used to measure saliva pH. I expect the three episodes of breathing in the water to show a decrease in tidal volume compared to controls and a decreased pH. Advisor: Dr. Laura Malloy.

 Seed discrimination by Black-capped Chickadees (Parus atricapillus) on basis of heft.
CHARLOTTE GABRIELSEN, Biology Department, Hartwick College. Heinrich et al. (1997) demonstrated that Black-capped Chickadees (Poecile atricapillus) take sunflower seeds selectively and discriminate between them on basis of heft. From February to May 2009, I performed experiments to determine if local populations of Black-capped Chickadees (1) discriminate among sunflower seeds on the basis of weight and (2) use visual cues to distinguish between lower- and higher-quality seeds. I conducted four different experiments consisting of 2 piles of seeds on a platform feeder with (1) normal (unmanipulated) versus empty seeds (seeds removed and hull glued together), (2) normal versus sham seeds (hulls opened and glued together without removing seed), (3) normal versus drilled seeds (small hole drilled into hull of seed), or (4) large versus small seeds. To record seed preference, I observed the seed pile visited and how many seeds were discarded for each visit of a bird to the feeder. I found evidence to support Heinrich et al's (1997) hypothesis: in the trial with the most bird visits, chickadees discarded fewer normal ( =2.24, S=1.45) seeds than empty seeds per visit ( =5.67, S=4.61; t=8.0, df=147.9, P<0.001). There was no significant difference between the number of normal ( =1.88, S=0.64) and sham seeds discarded by chickadees per visit ( =2.00, S=0.63; t=-0.36, df=12, P=0.72), suggesting that the preference for normal seeds over empty seeds in the first experiment was not because of the presence of glue on the empty seeds. I found no evidence that chickadees used visual cues when selecting seeds. There was no significant difference in the number of seeds discarded for large ( =1.03, S=0.16) and small seeds per visit ( =1.03, S=0.16; t=-1.05, df=181, P=0.29) and no significant difference between the number of normal ( =1.01, S=0.10) and drilled seeds that were discarded per visit ( =1.02, S=0.15; t=-1.39, df=74, P=0.17). In the future, continuous monitoring using PIT-tags (Passive Integrated Transponders) would allow for a greater understanding of seed selection in individual Black-capped Chickadees. Advisor: Dr. Peter Fauth.

Reducing growth stunting in children of the hilltribes of Northern Thailand with zinc-coated rice seeds.
JULIE HAMMONS, Biology Department, Hartwick College. This study found via that the children of two hilltribe villages in Northern Thailand are severely growth stunted according to international standards. Additionally, with blood serum analysis, the children were found to be deficient in zinc, an important component of many human enzymes and other proteins involved in growth, DNA replication and immune system functioning. The children's primary food source is rice. This study investigated coating rice seeds with ZnSO4 as a potential means of increasing zinc content in the children's diet. The concentrations of Zn2+ in rice seeds and soil from rice fields were determined with a LaMotte Zinc Analysis Kit to be zinc deficient. Later analysis via acid extraction and flame atomic absorption spectrometry (AAS) showed that the soil is low in zinc, but not deficient for agricultural purposes. Seeds were coated with 4.7 g ZnSO4/kg rice, and grown in a growth chamber under controlled temperature, light, and humidity conditions. The Zn2+ concentrations of the resulting rice plant tissues and seeds were determined via (AAS). Zinc-coated seeds did not have a higher Zn2+ concentration in seeds or plant tissues than uncoated seeds. Insufficient sample size and control of growth conditions may have contributed to the results; this experiment should be repeated in multiple fields in the hilltribe villages to reexamine the effect of zinc-coating on rice seed concentration under natural conditions. Advisors: Drs. Linda Swift and Andrew Piefer.

 Anti-microbial properties of three medicinal plants of Northern Thailand Thapo village.
CHRISTOPHER KRUCZYNSKI, Biology Department, Hartwick College.
The purpose of this study was to examine the antimicrobial properties of the Akha medicinal plants Deabajejung, Agaechet, and Long Sau. It was found that Deabajejung produced a zone of inhibition for the organisms S. aureus and S. epidermidis following the procedure for the Disk Diffusion/Kirby Bauer method of assessing effectiveness of antimicrobial agents. Deabajejung was then assessed for the presence of tannins, a chemical known to have antimicrobial properties, via 2-dimensional chromatography. It was observed that Deabajejung contained tannins similar to that of Camilla sinensis (Tea). Advisor: Dr. Linda Swift.

Effects of the Pesticide Atrazine on Development and Regeneration in Invertebrates. REBEKAH SEARLES, Biology Department, Hartwick College. Understanding the effects of environmental pollutants on living organisms is a major environmental issue. One of the most widespread pesticides in the United States today is the herbicide atrazine, a possible endocrine disruptor. The effects of atrazine have been studied in amphibians but comparatively little is known about its effects on invertebrate animals, especially on development and regeneration. The purpose of this experiment is to examine the effects of the pesticide atrazine on embryonic development and regeneration in snails (Phylum Mollusca) and flatworms (Phylum Platyhelminthes), common inhabitants of wetland ecosystems around the world. This research should provide insight into the effects of pesticide pollutants on invertebrates within the context of development and regeneration. Advisor: Dr. Stanley Sessions.

 The possible synergistic effects of high carbon dioxide levels and high nitrogen fertilizers on plant growth in Brassica rapa.
SCHUYLER STUART, Biology Department, Hartwick College. Global warming and the increase in CO2 in the atmosphere are now becoming very noticeable throughout the world. There has been a steady incline in CO2 emissions since the beginning of the Industrial revolution. This rapid increase has lead to an exceeding amount of infrared radiation residing in the earth's atmosphere, and this build up of heat has lead to an overall increase in global temperature which has lead to many environmental effects. One environmental effect of these increased temperatures is the enhancement of nutrient from the soil including Nitrogen in the form of NO3-. Some studies have suggested that these two effects may cause a synergistic enhancement of plant growth. To examine this possibility we will subject groups of plants to combinations of CO2 and NO3- conditions that may be present in the future, to determine if there is a detectable synergistic effect. At the end of each experimental period the plants will be collected and dehydrated to record the growth data. Advisor: Dr. Douglas Hamilton.

Microbial diversity in the hindgut of the tropical reef fish Kyphosus cinerascens
GINA TROY, Biology Department, Hartwick College. The microbial diversity in the hindgut of the tropical reef fish Kyphosus cinerascens was explored. Microorganisms in the gut are believed to digest algae consumed by K. cinerascens thus aiding the nutrition of the fish. The microbial community was explored by isolating DNA of organisms from hindgut samples collected from K. cinerascens. 16S rRNA genes (found only in bacteria) from the DNA were PCR amplified, cloned into Escherichia coli, and sequenced. These gene sequences were compared with others available in a large, public database to determine the identities of bacteria from which the genes were derived. The results of this study show that the microbial community in the hindgut of K. cinerascens is diverse and contains some bacteria also found in a related species, Kyphosus sydneyanus. Advisor: Dr. Mary Allen.
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Pattern Formation in the Regenerating Spinal Cords of Plethodon cinereus.
JESSIE WERNER, Biology Department, Hartwick College. A major goal of biomedical research is to understand cellular mechanisms of regeneration, particularly in regard to the mammalian nervous system. Unlike mammals, salamanders can regenerate their limbs, tails and a variety of other body parts. Tail regeneration involves complete regeneration of the spinal cord, but the cellular mechanisms are not understood. Previous research has shown that limb regeneration involves specific patterns of cell signaling. It is not known whether spinal cord regeneration utilizes similar cellular mechanisms. Retinoic acid (RA) is a powerful biochemical teratogen that disrupts cell signaling patterns and cell positional identity in predictable ways. In regenerating limbs, RA posteriorizes, ventralizes and proximalizes cell positional identity. If tail/spinal cord regeneration uses similar mechanisms as limb regeneration, then treatment with RA will have similarly predictable results. We tested this hypothesis in the Red-backed salamander, Plethodon cinereus. Results were analyzed morphologically, histologically, and immunocytochemically. Advisor: Dr. Stanley Sessions.
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