Kentucky Junior Academy of Science

      2000 Symposium Abstracts

         
    MICROBIOLOGY

    Effect of Sugars on Coaggregation of Micrococcus luteus and Pseudomonusfluorescens, JULIE WOLFE, Notre Dame Academy, 1699 Hilton Drive, Covington, KY 41011-2796.
         Biofilms are an assemblages of microscopic animals, plants, and bacteria attached to a surface.  They are of much concern in such diverse objects as industrial water pipes, dental tubing, and medical instruments.  An essential step in the formation of biofilm is the coaggregation of bacteria.  If the coaggregation of bacteria is inhibited, then biofilm is not able to form.  Lectin-like proteins are thought to be involved in the adhesion of the bacteria forming biofilm.  Lectins often attach to carbohydrates when functioning as cell adhesion proteins, so it seems logical that sugars might affect their action.  The purpose of my research was to see if adding sugar to the environment of two bacterial species expected to coaggregate would inhibit their adhesion. Pseudomonusfluorescens and Micrococcus luteus were exposed to 0.050 M solutions of glucose, sucrose, lactose, levulose, and mannitol.  Absorbances were read in a spectrophotometer and percent of coaggregation for the mixture was then calculated.  The calculations showed that glucose had a positive influence on the coaggregation of bacteria, while levulose had no effect.  Lactose dramatically enhanced coaggregation.  Results with sucrose and mannitol were inconclusive.
     

    Evaluation of Herbs as Protection against Ultraviolet Light.  ALEXANDRA MACPHERSON, Microbiology Department, Notre Dame Academy, 1699 Hilton Drive, Covington, KY, 41011-2796.
         The effects of ultraviolet rays on Saccharomyces cerevisiae, commonly known as baker's yeast, were observed in my experiment.  Herbs including rose extract, echinacea, thyme, and a combination of rose extract and echinacea were mixed into the yeast-extract dextrose medium. Saccharomyces cervisiae strain was plated on the media.  One plate of each kind was put under a germicidal UV light, while one of each kind was not.  In general, UV light was lethal to most yeast cells.  Rose extract and thyme could possibly supply some protection from the UV light.
     

    A Reporter Gene Assay for Methylpurine DNA Glycosylase. SARA DOERR, 412 Browns Lane., Louisville, KY, 40207. Mentor: Robert Baar,Louisville Traditional Male High School, 4409 Preston Highway, Louisville, Ky and Dr. Thomas Geoghegan, Ph.D, University of Louisville, Louisville, KY.
         The purpose of this experiment was to analyze the expression of methylpurine DNA glycosylase, a base excision repair gene. The regulatory elements of the gene were to be determined by inducing DNA damage through the use of dimethyl sulfate and examining promoter activity using a luciferase reporter gene assay.  Transfection into two vectors, pCR 2.0 Blunt Vector and the pGL2 vector was necessary.  HepG2, cells were used.  DMS (dimethyl sulfate) was used to treat the cells for 5 hours and 72 hours.  b-galactosidase was used as a positive control for the experiment.  The assay for these cells showed that the activity of the cells made a relatively small change when treated with DMS for 5 hours.  Treatment for 72 hours, however, caused a dramatic decrease, which could be explained by unbalanced repair.
     

    A Transgenic Construct for the Cardiac-Specific Expression of MCAR: Testing In Vivo Heart Gene Therapy.  YAN XUAN, MST Program, duPont Manual High School, 120 West Lee Street, Louisville, KY 40242.
         A transgenic construct for the purpose of developing a mouse model for testing in vivo heart gene therapy.  Current gene therapy methods are ineffective due to the lack of expression of the Coxsackie Adenovirus Receptor (CAR) in non-liver organs.  CAR is the receptor protein for the adenovirus, the most widely used carrier in gene therapy techniques, and is essential in the binding of the adenovirus before infection.  In order to facilitate adenovirus transfection in cardiomyocytes, and thus making heart gene therapy more effective, a specific transgene was constructed.  A murine form of the CAR gene (MCAR) was excised and cloned into a vector containing the a-MyHC promoter, selected because of its high transcription percentage and extreme specificity to cardiomyocytes, the target of transfection.  This transgene was successfully constructed and can now be used to develop transgenic mouse to serve a model in testing gene therapy.  This model currently does not exist, nor did a transgene utilizing MCAR for gene therapy before this study.  The derived mice should have increased levels of expression of MCAR in the adult heart, thereby increasing transfection of adenovirus injected during gene therapy.  Other investigators are also developing MCAR knockout mice, where MCAR is removed from all organs other than the heart, primarily the liver.  The transgene developed in this study can be used independently, or in conjunction with the knockouts in development.  This dual model, obviously, would be a significant improvement in gene therapy testing models.
     

    The Effect of Various Commonly Used Substances on the Inhibition Zones of Various Antibiotics on Various Bacteria.  ANDREW B. THAI, duPont Manual High School, 120 West Lee Street, Louisville, KY 40208.
         The purpose of this experiment was to investigate the effect of various commonly used substances on the inhibition zones of various antibiotics on various species of bacteria.  It was hypothesized that with various substances combined with various antibiotics, that at least some of the combinations would exhibit the ability to serve as mutagens, by potentially altering the functional mechanism of antibiotics or chemistry of the DNA within bacteria, causing a mutation.  The antibiotics and substances were tested for possible inhibition or enhancement of effects on bacteria. Escherichia coli and Staphylococcus aureus, gram positive bacteria, were chosen for experimentation.  The primary technique used to collect the data was the disk diffusion susceptibility method.  This method allows combinations of the substances and antibiotics to be tested on Petri dishes in an even distribution manner so zones of inhibition could be observed.  The antibiotic disks and substance disks could be tested together to analyze synergism.  It was discovered that commonly used substances such as vitamins, pain relievers, and herbal remedies do, in fact, serve as synergistic mutagens.  Also, the majority of the combinations of antibiotics and the substances have the capability to enhance inhibitory zones, therefore producing synergistic results.  This synergism also has the possibility of affecting resistant rate and probability.  Therefore, these results present a fresh and dynamic approach to tackling the decline of antibiotic effectiveness.  The war against resistant bacteria may not depend directly on antibiotics or bacteria, but instead in possible mutagens previously ignored that could effect the overall outcome.
     

    The Effect of Curcumin as a Sensitizer of Radiation on Human Cancer Cells. DAVID MEIGOONI, Leestown Math, Science and Technology Magnet School, Lexington, KY 40511.
         Curcumin is an orange crystalline powder coming from the plant Curcuma longa.  One form of this product is commonly known as turmeric, which you may see it in some foods, for example, yellow rice.  Curcumin has many clinical applications such as anti-inflammatory, anti-bacterial, and anti-tumor properties.  Several investigators had published about its anti-cancerous properties.  They have shown that if curcumin serum is taken orally at 500 mg/day, it prevents DNA damage caused by cancerous cell.  Also, it has been shown that curcumin is an inhibitor, (i.e. prevents) of cancerous cells.
         The goal of this project is to measure the effect of curcumin as a sensitizer of radiation on PC3 prostate cancer cells.  This effect was measured by comparing the survival fraction of the PC3 prostate cancer cells as a function of radiation dose with an addition of 2 mM (i.e. micro molar) and 4 mM concentration of curcumin as a sensitizer to the survival fraction of the cells with radiation alone.  Enhancement of the radiation effect by the curcumin was determined as a ratio of SF2 (i.e. survival fraction for 2 Gy radiation) with radiation alone, to the SF2 with addition of curcumin.  My results indicated that for 2 mM and 4 mM curcumin the radiation effects were enhanced by 2.9 and 17.4, respectively. This data indicates that curcumin is acting as a cell sensitizer for radiation.
     

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