What effect do organic and traditional insecticidal treatments have on human pathogen Escherichia coli 0157:H7 and beneficial bacterium Azotobacter vinelandii in soil?
E. coli 0157:H7 is a major cause of foodborne outbreaks in the United States. Often contamination of vegetables and fruits begins with the contamination of the soil in which they are grown. Some insecticidal fumigants have been shown to reduce the amount of harmful bacteria in soil and so this study attempts to determine the effect of organic, home-remedy, and synthetic pesticide treatments in reducing the amount of E. coli O157:H7 in soil samples without harming beneficial bacteria. Soil samples contaminated with E. coli or A. vinelandii will be treated with a variety of insecticides, incubated for various lengths of time and then the number of bacteria quantified by dilution and plating. The ideal treatment will decrease the number of pathogenic bacteria while not harming the beneficial bacteria.
Does exposure to gluteraldyhyde affect central nervous system development of Drosophila melanogaster?
Glutaraldehyde is a chemical used in oil fracturing, which is a method used to extract natural gas from shale rock. Water, sand and a mixture of chemicals are pumped into the rock and left to seep into group water. In this study, I monitor central nervous system development in Drosophila melanogaster to determine the dangers of glutaraldehyde on a developing embryo. Observing this system will help us understand potential developmental hazards the chemical poses to the development of living organisms, including humans.
How many and what types of bacteria are present on tomatoes from local farms and markets in the Austin, Texas area?
In recent years organic food sales have increased. It has been hypothesized that organic products are more likely to transfer pathogenic bacteria to consumers than traditional produce. This study examines the number and kinds of bacteria present on tomatoes grown and sold locally. Local tomatoes will be collected and the surface bacteria cultured and quantified on tryptic soy agar using a dilution and plating procedure. The bacteria will be identified using Gram staining and 16s rRNA gene sequencing. This study will provide knowledge about what bacteria are able to remain on the surface of tomatoes and can be compared to similar studies from other locations.
How does ethanol exposure affect central nervous system and anterior-posterior axis patterning in Drosophila melanogaster?
In humans, prenatal ethanol exposure can lead to fetal alcohol syndrome, which is the leading cause of congenital mental impairment in the Western world. It is known that ethanol adversely affects development in model organisms as well, causing a range of physical malformations. Previous research has shown that some of these malformations are due to exposure to ethanol during the late stages of development. Using Drosophila melanogaster as a model organism, this study examines the effects of ethanol on the development of the central nervous system (CNS) and anterior-posterior axis (A-P) patterning during embryogenesis, an earlier stage in Drosophila's development which would be roughly equivalent to the first trimester of a human pregnancy. Drosophila will be exposed to ethanol throughout embryogenesis by exposing newly hatched eggs to ethanol-soaked cotton. Observing early CNS and A-P patterning abnormalities may better explain the mechanics of ethanol as a teratogen.
Can epazote, oil of chenopodium, or Alka-Seltzer effectively remove or inhibit Escherichia coli 0157:H7 on contaminated pre-packaged spinach when used in a wash?
E. coli 0157:H7 is responsible for 73,480 illnesses, 2,168 hospitalizations, and 61 deaths in the United States annually. Shiga toxin, produced by the pathogen, causes harsh damage to the lining of the intestines, inhibits protein synthesis in the cells of small blood vessels, and can cause bloody diarrhea and renal failure. This study will examine the antimicrobial properties of epazote, oil of chenopodium, and Alka-Seltzer in washes on E. coli 0157:H7. These products will be compared with sterile water and a store-bought vegetable and fruit wash. Spinach will be contaminated with E. coli 0157:H7, washed with the products and then the bacteria quantified by dilution and plating. If effective, these washes could be used by consumers to decrease the risk of foodborne illness due to leafy green vegetables.
How well do antibacterial contact lens solutions inhibit the growth of Pseudomonas aeruginosa?
Pseudomonas aeruginosa is a bacterium frequently found in soil and water that can cause disease in humans. This bacterium can take advantage of corneal trauma and cause invasive infections resulting in blindness. This study examines the ability of contact lens solutions to inhibit P. aeruginosa. Contact lens solutions will be placed in lens cases and contaminated with P. aeruginosa. After various incubation times at room temperature and at 37°C the solutions will then be diluted and plated in order to quantify the bacteria. These results will help to guide contact lens wearers when choosing a storage solution.
Does kekkon 1 influence the diversity of eggshell phenotypes in Drosophila melanogaster?
Dorsal appendages are paired appendages on the fruit fly egg that allow for increased oxygen intake for the embryo inside. Although present in all Drosophila species, the number of appendages can vary between species; for example, Drosophila virilis, exhibits four appendages, while D. melanogaster and D. melanica only have two. In my experiment I will be testing three species of fruit flies including D. melanogaster, D. melanica, and D. virilis. Using in-situ hybridization, I will analyze the expression pattern of the gene kekkon 1 which is involved in the inhibition of the signaling pathway involved in specifying dorsal appendage number and positioning. It is known that inhibition of a single initial domain of signaling results in the formation of two dorsal appendages in D. melanogaster; here I will examine whether a second inhibition by kekkon is correlated with the formation of four appendages in D. virilis. From this experiment I hope to learn whether kekkon 1 is involved in the patterning events that specify how many dorsal appendages form on the eggshell.
Tony Voong and Katie Vaziri
How does genetic background alter the phenotypic effects of mutations in Drosophila melanogaster?
Drosophila melanogaster has long been used to study the effect of genetic mutations on developmental phenotypes. Previous studies have demonstrated that the phenotype associated with a particular mutation depends not only on the mutation itself, but also the genetic background in which it is expressed. In this study we will examine the effect of different genetic backgrounds on the expression of mutant phenotypes that affect dorsal appendage positioning on the eggshell. Dorsal appendages are extensions of the eggshell that help to deliver oxygen to the embryo developing inside; previous research has shown that the placement of appendages on the eggshell is dependent on signaling through the EGFR pathway. We will examine whether changes in genetic background affect the severity of phenotypes associated with known mutations in the EGFR pathway.
What is the microbial content of drinks obtained from soda fountain dispensers?
Soda fountain dispensers can be found in many food establishments, hospitals, and gas stations and there are currently no regulations to monitor the microbial content of drinks from these machines. Their popularity makes the issue of contamination a major concern. In a previous study undertaken in Virginia, drinks from these machines were most contaminated in the morning. In this previous study a number of bacteria were isolated including: Chryseobacterium meningosepticum, and species of Klebsiella, Staphylococcus, Stenotrophomonas, and Serratia. The current study will use dilution and plating and 16s rRNA gene sequencing to examine the microbial contamination of soda fountain beverages in Austin, TX and will test whether fountains with higher use will be less contaminated.