2010 BIOLOGY HONORS STUDENTS
Congratulations to All!
Dr. Jim Vigoreaux, Samuel David Paskin-Flerlage, Katherine Colby Jerome, Tyler Aten, Raymond Lee, Alison Krywanczyk
Samuel David Paskin-Flerlage received the Bernd Heinrich Award in Physiology or Evolution. This award is presented to a student doing outstanding research in physiology or evolution. Mr. Paskin-Flerlage is from Ithaca, NY and has conducted Honors research in molecular evolution and completed a minor in chemistry. After graduation Samuel will work in the laboratory of Dr. Paul Yu, Division of Cardiology at Harvard Medical School. The title of his thesis is Characterization of the Spatial Expression of Flightin among Arthropods: An Evolutionary Investigation of the Specialization of a Flight Muscle Protein.
Abstract
Within Drosophila melanogaster, the myosin binding protein flightin is unique to the indirect flight muscles (IFM), where it has been shown to fulfill functions essential for maintaining sarcomeric integrity and necessary for the stretch activation response that powers flight. Recent studies have identified a highly conserved ~55 amino acid region of flightin, denoted as WYR, that is found in the genomes of many other arthropods, although its expression and function in organisms other than Drosophila sp. has yet to be explored. In this study, we characterized the transcriptional expression patterns of WYR within the crustacean Daphnia (waterflea), and representatives of the insects Plecoptera (stonefly), Odonata (dragonfly), Megaloptera (fishfly), and Orthoptera (grasshopper). Using the conserved WYR sequence as an identifiable genomic marker, flightin transcription was evaluated by segment-specific RT-PCR and in situ hybridization. In all organisms studied, flightin was expressed more broadly than in D. melanogaster, where flightin is spatially limited to the IFM. Flightin expression was also identified in larval Odonata and Megaloptera, suggesting that in these orders the temporal specificity observed in D. melanogaster is not conserved. These data suggest that the tissue specific expression profile observed in D. melanogaster may be a derived character state, and that flightin may fulfill additional unidentified roles outside Drosophila.
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Katherine Colby Jerome received the George Perkins Marsh Award in Ecology/Evolution. This award is presented to a student doing outstanding research in ecology and evolution. Ms. Jerome is from Shaftsbury, VT and has conducted Honors research in molecular ecology and completed a double minor in Chemistry and Studio Art. Katherine is going to take a year off to travel and hike the Long Trail before entering dental school to become a general practitioner dentist. The title of her thesis is Age Estimation of Live Little Brown Bats and Big Brown Bats Using Telomere Measurement by Quantitative PCR.
ABSTRACT
Bats live longer than any other mammal for their body size and are traditionally aged by morphological characteristics. The North American big brown bat (Eptesicus fuscus) and the little brown bat (Myotis lucifugus) can be classified into two broad age groups, juveniles (< 3 months of age) and adults (> 3 months of age), but there is no other reliable method to determine a bat’s relative age. Like other long-lived animals, the length of the telomeric DNA was predicted to shorten as a function of increased age. Genomic DNA was extracted from wing punch samples, a relatively noninvasive collection method, taken from known aged bats from natural populations. Quantitative polymerase chain reaction (qPCR) was performed to determine the telomere length, by estimating relative telomere (T) to single copy gene 36B4 (S) ratios. A regression analysis of relative T/S ratio and age was performed for each species with the expectation that the relative age of a bat could be estimated by its relative T/S ratio. Initially, there was no significant relationship between age and relative T/S ratios obtained from wing punch samples from either species (big brown bat, p = 0.4397, R2 = 0.0182; little brown bat, p = 0.051, R2 = 0.2439), but once additional factors, i.e. initial quantity of extracted DNA and DNA purity levels, were taken into consideration a significant correlation was revealed for the little brown bat (p = 0.041) but not the big brown bat (p = 0.630). In addition, a broad range of intraspecies variation was observed (big brown bat, p = 6.16E-34; little brown bat, p = 1.06E-6). It was determined from this study that the amounts of telomeric DNA may serve as an appropriate means to estimate age for the little brown bat but not for the big brown bats, yet modifications to the procedure (i.e. selection of a different telomere gene and alternative tissue as a source of DNA) could potentially reveal a relationship between telomeric DNA and age.
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Tyler Mills Aten received the John Wheeler Award in Chemical Biology. This award is presented to a student doing outstanding research in chemical biology. Mr. Aten is from Montpelier, VT and is a McNair Scholar who conducted Honors research in Proteomics. Next year, he will be attending the University of Connecticut School of Dental Medicine, with hopes of becoming an oral maxillofacial surgeon. The title of his thesis is Identification of a Novel Cooperative Activity between the Proto-oncogenic Src Family Kinases and Crk/CrkL Signaling Protein Families.
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Raymond T. Lee received the Paul A. Moody Award in Biology. This award is presented to a student with the highest research achievement in biology. Mr. Lee is from Marstons Mills, MA and has conducted Honors research in childhood cancer and completed a double minor in Chemistry and Microbiology. He will be attending medical school after he graduates. The title of his thesis is Neuroblastoma (NB) is a Fatal Childhood Cancer of the Sympathetic Nervous System.
ABSTRACT
Wesley’s lab has recently shown that a cell surface protease called DPPIV is expressed in normal neural crest derived differentiated cells but lost in NB, the malignant counterpart. Re-expression of DPPIV in NB cells leads to their differentiation, apoptosis, and suppression of angiogenic potential. To further identify DPPIV-responsive genes and mechanisms, we used Affymetrix microarray analysis, which showed an association of DPPIV expression with up-regulation of thrombospondin-1(THBS1), an angiogenesis inhibitor. Interestingly, some of the genes regulated by DPPIV are also altered by microRNA (miRNAs). miRNAs are small non protein-coding regulatory RNAs and play critical roles in cancer development by regulating cell differentiation, angiogenesis and apoptosis through post-transcriptional gene regulation. Thus, we hypothesized that at least some of the miRNAs might act as intermediate effectors in mediating DPPIV function. Using a human cancer specific miRNA PCR array, we found that DPPIV expression indeed alters miRNA profile in NB cells. Particularly, DPPIV down-regulated miR-19a which is part of the miR-17-92 cluster that is known to target THBS1. Furthermore, bioinformatics data mining of MicroCosm Targets predicted THBS1 as a potential target of miR-19a suggesting that down-regulation of miR19a leading to up-regulation of THBS1 was a possible mechanism involved in DPPIV tumor suppressor function. In support of this idea, we demonstrated that silencing of DPPIV expression by RNA interference results in increased miR-19a and decreased THBS1 expression. Furthermore, transfection of NB cells with anti-miR-19a also decreased miR-19a and increased THBS1 levels as shown by real time quantitative RT-PCR, immunofluorescence and western blot analysis. DPPIV expression and anti-miR19a also decreased the levels of bFGF and VEGF, two strong downstream pro-angiogenic factors. Taken together, our work identifies a novel and an important mechanism wherein DPPIV inhibits angiogenesis and growth of NB tumor cells by down-regulating miR-19a, thereby increasing THBS1 expression.
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Alison Rae Krywanczyk received the Lyman S. Rowell Award in Biology. This award is presented to the student with the highest achievement in biology. Ms. Krywanczyk is from Essex Junction, VT and has conducted Honors Research and completed a minor in Chemistry. She’ll be attending UVMs College of Medicine in the Fall. Her advisors are C. William Kilpatrick, PhD and Steven Shapiro, MD. The title of her thesis is A Retrospective Review of Vermont Suicide by Firearm: 2003-2008.
ABSTRACT
In Vermont, suicide is the 8th leading cause of death (VDH 2005), but nationally suicide is only the 11th leading cause of death (CDC 2005). Previous studies have also indicated Vermont has an elevated rate of firearm suicide when compared to other states in the region (Miller et al. 2004). It is possible that the leniency of gun-purchasing laws in Vermont contribute to this elevated suicide rate by making a highly lethal method of suicide readily available, even for passing, spontaneous suicidal urges. Records at the Vermont Office of the Chief Medical Examiner between 2003 and 2008 were used to obtain the rate of suicide and firearm suicide in Vermont, and to determine when the firearms were obtained relative to death in each case. When compared to Massachusetts and Rhode Island, (states with stricter gun-purchasing laws but also lower rates of home firearm ownership), Vermont had a significantly higher rate of suicide and suicide by firearm (14.69 per 100,000 and 7.35 per 100,000). Out of 274 suicides by firearm, only 46 of these cases contained information on the source of the firearm. 22 of these were obtained on the day of suicide, (4 purchased, and 18 borrowed), and another 4 were acquired within one week of the suicide (3 purchased, 1 borrowed). While these data are incomplete, indicating a need for more investigation of suicides, it indicates that properly securing home firearms and perhaps initiating a waiting period for firearm purchase could affect suicide rates in Vermont.