Journal of Biological Research, Vol. 11 (2010)

 Does pH influence the antimicrobial effects of spices? Jeff Beckenbach, Department of Biology, Hartwick College, Oneonta, NY 13820. Human spice use may be an evolved trait to reduce food-borne disease.  Consequently, Sherman and Billing (1998) predicted that spice use is greater in warmer climates where food- spoilage rates are higher, and that the spices frequently used in cuisine reduce microbial growth.  Although Sherman and Billing (1999) found widespread support for these predictions, the use of lemon juice was not consistent with the antimicrobial hypothesis.  I tested the hypothesis that lemon juice is used to reduce the pH of cuisine, making certain spices more effective as microbe inhibitors.  I used traditional cookbooks to identify spices frequently and infrequently used with lemon juice.  Using a disc-diffusion assay, I investigated the antimicrobial properties of spices used alone and together with lemon juice.  Contrary to my prediction, none of the spices commonly used with lemon juice, but 2 of 3 species rarely used with lemon juice inhibited E. coli more when combined with lemon juice than when used alone.  These results do not suggest that lemon juice is used to enhance the antimicrobial activity of spices.  Further evaluation of the antimicrobial hypothesis should consider a protocol that more closely resembles the complex interactions between spices, heat and lemon juice used in cooking. Faculty Supervisors: Drs. Mary Allen and Peter Fauth.

Sensitive Period of Temperature-Induced Color Variation in Monarch Larvae (Danaus plexippus). Cassie Dresser, Department of Biology, Hartwick College, Oneonta, NY 13820. Coloration affects the thermoregulation of monarch butterfly (Danaus plexippus) larvae.  Because environmental temperature varies temporally, selection favors phenotypic plasticity in the monarch's color pattern.  In particular, monarchs exposed to cold temperatures during the egg and larval stages exhibit more black coloration than those exposed to warmer temperatures.  Because coloration of larvae is not reversible, I predicted that a sensitive period exists during the larval stage in which the degree of color pigmentation is determined.  To investigate this prediction, I measured the amount of black pigmentation on monarch larvae that were exposed to cold temperatures for a randomly assigned number of days.  I found no evidence of a sensitive period during the 4th or 5th instars; there was no relationship between the number of days in which larvae were exposed to cold temperature and their percentage of black color, nor was there an increase in black pigmentation on individual larvae between the 4th and 5th instars.  Because phenotypic plasticity in monarch larvae has been experimentally demonstrated, I suggest that the sensitive period exists during early stages of development, either the egg stage or early larval instars. Faculty Supervisor: Dr. Peter Fauth.
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Patterns of Cell Proliferation in Developing Salamander Limbs.  Finnegan Hewitt, Department of Biology, Hartwick College, Oneonta, NY 13820.  Our research project is focused on an analysis of the pattern of cell proliferation in the embryonic limbs of species representing basal lineages of salamanders thought to have limbs that may be closer to the ancestral state than other tetrapods.  These species represent some of the diversity of urodeles in terms of cell size and quantity of DNA as well as geographic distribution. Histology and anti-BrdU immunocytochemistry were used to label cells in S-phase of the cell cycle. Our results show a tight correlation between proliferation and morphological patterning in developing limbs, supporting the hypothesis that pattern formation depends on cell proliferation in salamanders. Faculty Supervisor: SK Sessions.

Antibiotics and Antibiotic-Resistant Bacteria in the Upper Susquehanna River.  Emaly Leak, Department of Biology, Hartwick College, Oneonta, NY 13820.  Antibiotics discharged into the Susquehanna River from the Oneonta Wastewater Treatment facility could select for the enhanced growth of antibiotic-resistant bacteria.  This study aimed to quantify antibiotic concentrations and proportions of bacteria with antibiotic resistance upstream of, at, and downstream of the Oneonta Wastewater Treatment Plant outflow.  Four replicate samples were collected at each site once a month for seven months during the spring and summer of 2009.  Water subsamples were prepared using solid-phase extraction and analyzed for antibiotic concentration using liquid chromatography - mass spectrometry.  Other subsamples were filtered and plated on media selective for the growth of coliform bacteria, common inhabitants of mammalian intestines.  Isolated bacteria were tested for resistance to five antibiotics.  Proportions of antibiotic-resistant bacteria were significantly higher at the outflow (p<0.01) and downstream (p<0.01) when compared to upstream.  There was no overall trend regarding a temporal effect (time of year) on proportions of antibiotic-resistant bacteria.  There were significantly lower proportions of resistant bacteria in only April, compared to all of the other six months (p<0.01).  Water temperature may have influenced both variation between sites and between dates, as temperature was always higher at the outflow, and temperature was much lower during April compared to the other months.  There were no detectable amounts of antibiotics found in the water, but it is possible that the antibiotics were present below the detectable concentration limits of the instrument used or that they were quickly metabolized or photo degraded into different compounds that our methods could not account for. Faculty Supervisors: Dr. Mary Allen & Dr. Zsuzsanna Balogh-Brunstad.

Olfactory Lobe Regeneration in Red-Spotted Newts.  Yuri Mataev, Department of Biology, Hartwick College, Oneonta, NY 13820.  The purpose of this studywas to determine the ability of red-spotted newts (Notophthalmus viridescens) to regenerate the frontal (olfactory) lobe after surgical removal. Some rearrangment or remodeling (and possibly re-growth) of neural tissue was observed, but the damaged area did not regenerate to its original size and structure over the course of the recovery period. Anti-BrdU immunocytochemistry showed dividing cells along the edge of the damaged area of brain, especially in the ependyma, as well as in blood clots, indicating that at least limited neural regeneration was taking place. Faculty Supervisor: Dr. Stanley K. Sessions.

The origin of cardiomyocyte stem cells in regenerating hearts of Notophthalmus viridescens.  Dwayvania Miller. Department of Chemistry, Hartwick College, Oneonta, NY 13820. The purpose of this study was to investigate the origin of cardiomyocyte stem cells in the regeneration of heart tissue in Red Spotted Newts (Notophthalmus viridescens).  Regenerating newt hearts contain a blood clot that becomes populated by dividing cells.  We hypothesized that the blood clot may be the source of activated stem cells for new cardiomyocytes. This hypothesis was tested by analyzing the expression patterns of the pre-cardiomyocyte transcription factors tbx20, nkx2.5, and gata4 in newts that are regenerating their hearts. This was done by using RT-PCR on RNA extracted from regenerating and non-regenerating heart and blood clots. The results indicate that the cardiac-specific transcription factor (tbx20) is expressed in cardiac blood clots in heart- regenerating newts. Since dividing cells have only been detected in the blood (including the clot), these results suggest that pre-cardiomyocyte activated stem cells originate from blood cells in newts. Faculty Supervisors: Dr. Andrew J. Piefer and Dr. Stanley K. Sessions.

Analysis of Zinc and Iron Levels in Rice (Oryza sativa) Treated with Zinc Sulfate and or Iron Sulfate in Fertilized and Non-fertilized Fields in Northern Thailand.  Erika Mohr, Department of Biology, Hartwick College, Oneonta, New York, 13820.  Malnutrition causes growth stunting in hilltribe children. Previous research (Hall, 2007, Hammons, 2008), indicates growth stunting is significantly correlated with low serum zinc and protein levels (P=0.000). Soil zinc levels were determined to be critically deficient (0.08-0.10 ppm Zn2+) (Hammons 2008). Zinc deficient soil can contribute to zinc and protein deficient rice and children. Only about 10-10 mol 1-1, or 1% (0.1-2.5 ppm) of iron in the soil is soluble and can be absorbed by rice plants (Meng, 2005). Iron deficient soil can also yield iron deficient rice which can lead to anemia and further malnutrition in children. This study will determine if zinc sulfate and or iron sulfate treated rice seeds will increase zinc and iron in rice and children. It will also determine if adding a urine fertilizer (diluted with water in a 1:5 urine to water ratio) to the soil will enhance production and growth in the plants. During the summer of 2009, zinc and iron treated rice were planted in Akha rice fields. Some of the zinc sulfate and iron sulfate treated plants were planted with a quantitative amount of diluted urine fertilizer (1:5 ratio). The seeds from the plants were dried and sent to Hartwick. Analysis of iron and zinc content in rice grains was determined and statistically analyzed. Soil from the fields was also analyzed for zinc, iron and other micronutrients important for rice seed growth. The projects significance is to provide more zinc and iron (through zinc and iron presence in the plants) in the diet to enhance growth in children. Faculty Supervisors: Dr. Linda A. Swift and Dr. Richard Benner.

Does Insulin-like growth factor-1 Induced Neovascularization Require Activation of Tyrosine Kinase Linked Receptors?   Alison J. O'Mara, Department of Biology, Hartwick College, Oneonta, NY 13820. AG1024 is a highly selective inhibitor of the protein tyrosine kinase-linked receptors of IGF-1. We studied the ability of AG1024 to inhibit IGF-1-induced blood vessel growth in chorioallantoic membranes (CAMs) of chick embryos. Our results showed that AG1024 in the presence of IGF-1 significantly reduced the number of blood vessels when compared with IGF-1 alone. These results suggest that in the CAM, IGF-1 induced angiogenesis is mediated through the action of IGF-1 and PTK receptors. Faculty Supervisor: Dr. Laura Malloy.

Does inhibition of a protein Tyrosine Kinase receptor using the PTK inhibitor NVP-AEW541 inhibit IGF1 induced angiogenesis?   Stacey Roberts, Department of Biology, Hartwick College, Oneonta, NY 13820. The purpose of this experiment was to determine if IGF-1 induced angiogenesis can be inhibited through the use of NVP-AEW541, a new drug that blocks the tyrosine kinase receptors to which the IGF-1 binds.  Theoretically, if NVP-AEW541, is applied along with IGF-1 it will block down stream signaling of the tyrosine kinase receptors and therefore reduce angiogenesis in the cells.  We tested this hypothesis using the chick chorioallantoic membrane, or CAM, assay. We placed pellets containing concentrations of DMSO vehicle (control), IGF-1, NVP-AEW541, and a combination of both on the membranes of the growing chick embryos. This study demonstrated for the first time that NVP-AEW541 can inhibit IGF-1-induced angiogenesis in the chicken chorioallantoic membrane.  As a result NVP-AEW541 may decrease the aggressiveness of cancers.  The results will supplement other findings regarding the role that tyrosine kinase receptors play in angiogenesis. Faculty Supervisor: Dr. Laura Malloy.

Does the Guide Effect Cause Gregariousness in the Caribbean Spiny Lobster Panulirus argus?  Richard C. Ross, Department of Biology, Hartwick College, Oneonta, NY 13820.  Understanding social behavior is one of the major goals of behavioral ecology.  Research conducted in Florida claims that Caribbean spiny lobsters that associate in shelters benefit from the guide effect, or the ability to quickly locate shelter by locating conspecifics.  This project will be the first experimental field test relating to this hypothesis for spiny lobster social behavior.  Field research was conducted at the Gerace Research Centre (GRC), San Salvador, Bahamas in January, 2009, to test 2 predictions of the guide effect hypothesis: that lobsters are spatially aggregated and that lobsters will be attracted to occupied shelters more often than unoccupied shelters.  I found that lobsters are aggregated in dens around San Salvador.  Unfortunately, lobsters were not attracted to occupied nor unoccupied artificial shelters.  This indicates lobsters are living gregariously, but the reason for group living remains unknown. Faculty Supervisor: Dr. Mark Kuhlmann.
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The Role of Sonic Hedgehog Cell Signaling in Face Development.   Hira Siddiqui, Department of Biology, Hartwick College, Oneonta, NY 13820.   The main goal of this research was to test the hypothesis that sonic hedgehog cell signaling is involved in face development of amniotic embryos, as well as to figure out the most sensitive developmental stage when the embryos are most susceptible to developing facial abnormalities. This hypothesis was tested by treating developing chicken embryos at three developmental stages with cyclopamine. Cyclopamine is thought to inhibit the hedgehog signaling pathway (Hh) by influencing the balance between the active and inactive forms of the smoothened protein which is required by Shh for normal function. Our results indicated that sonic hedgehog is in fact involved in face development of amniotic embryos and that the most sensitive developmental stage was Stage 6 (early neurulation). Faculty Supervisor: Dr. Stanley Sessions.

Prevalence of Streptococcus Lancefield Group C on the Hartwick College Campus.  Sadia Siddiqui, Department of Biology, Hartwick College, Oneonta, NY 13820. Streptococcus Lancefield Group C (Strep C) bacteria is a known causative agent of pharyngitis. It is known to rarely cause disease in humans but can colonize certain parts of the body including the skin, the newborn umbilicus and other mucosal surfaces like the nose, throat and vagina. The most common reservoirs of Strep C are milk, livestock and other infected humans and it is most commonly transmitted through direct contact with an infected human or non-human host, although, it may be transmitted intravenously. Casual observations by local authorities (personal communication: Elizabeth Morley, RN, Director of Perrella Health Care Center of Hartwick College and Russell Grant, Director of Infection Control at Fox Memorial Hospital Oneonta NY) suggest that the routine diagnosis  of Strep C pharyngitis amongst Hartwick College is endemic on Hartwick College campus. This study therefore determined the proportion of the student body of Hartwick College campus that are (asymptomatically) infected with Strep C and looked for common associations amongst members of the infected population using data collected from written surveys. The commonalities were then examined to look for possible reservoirs on campus. One hundred and sixty seven throat swab cultures were obtained from student volunteers on Hartwick College campus on three assigned dates starting March 2010. These cultures were grown on sheep blood agar plates and the different hemolytic colonies were then tested for Lancefield Group C using a latex agglutination test. The results show that 7.2% of the tested population is positive for Streptococcus Lancefield group C. Our data suggests that there is no significant association between being positive for Strep C and any of the tested variables. However, using chi squared analysis, we found a significant association (p<0.05) between the variable resident dorm and testing positive for Strep C. Further analysis of the data, revealed an unusually high count of individuals that tested positive for strep C residing in the dorm Leitzell. Faculty Supervisor: Dr. Mary Allen.
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The Impact of Genome Size on Developmental Rate in Salamanders. Danielle Wasserman, Department of Biology, Hartwick College, Oneonta, NY 13820.   Genome size is known to impact cell size and cell division rate in salamanders but it is unknown whether or not it has a predictable impact upon rate of development of the whole embryo. Here we examined embryonic development in two species of salamanders representing two very different genome sizes. The smaller genome species had much smaller embryos and developed at a significantly faster rate than the large-genome species. Other than size, the overall morphology (shape) of the embryos of the two species was generally very similar. These results are probably explained by the known positive correlation between genome and cell size, as well as the negative correlation between genome size and mitotic rate.  These results are discussed in the context of the biological significance of genome size evolution in salamanders. Faculty Supervisor: Dr. Stanley K. Sessions.