Last Year‎ > ‎

Sarah Carlson & Siddarth Eswarachari

Project Summary
This study reports a protocol to identify methyl-accepting chemotaxis receptors in Pseudomonas putida F1 that detect the aromatic nutrient homogentisate, with the long-term goal of engineering the bacteria to catabolize aromatic hydrocarbons. Sixteen P. putida F1 methyl-accepting chemotaxis protein receptors were screened using two quantitative colorimetric assays—MacConkey and ß-galactosidase. Results showed that the ß-galactosidase assay is more effective in identifying response of P. putida F1 methyl-accepting chemotaxis protein receptors to the presence of homogentisate. Results of ß-galactosidase assays also showed that chemotactic response of the P. putida 0339 (p = 0.0069) and the P. putida 3489 (p = 0.0275) were significantly greater in the presence of homogentisate than in the absence of homogentisate (control). In verification tests, both P. putida F1 ∆0339 and ∆3489, where the methyl-accepting chemotaxis protein receptors 0339 and 3489 were knocked down, respectively, showed unexpected response to homogentisate that was not consistent with the ß-galactosidase assay results. This suggests that when one receptor is knocked down the remaining receptor may compensate. The next step is to repeat verification using the double knocked-down P. putida F1 receptors 0339 and 3489.
Sarah Carlson
I am a senior, and I came to Breck in my freshmen year. Over my time at Breck, I have participated in many activities. I love to spend my time by being involved in many other activities. I love music and participate in a wide variety of musical activities. I play violin with the Greater Twin Cities Youth Symphonies, as well as trumpet, recreationally and with our school band. I enjoy the contrast between classical and jazz music and like to throw in marimba music, too! In fact, I am a member and leader of Bato Bato, the Breck marimba band club. Aside from music, I also enjoy a couple of other creative outlets: knitting and jewelry making. I even created a business, Sarah’s Designz (, which spawned from my passion for these two hobbies. Yet, when I am not doing any of the aforementioned actives I enjoy volunteering—especially with Minnesota Special Olympics—and hanging out with friend.
Siddarth Eswarachari
I am a senior, and I came to Breck my 8th grade year. I had the opportunity to participate in many activities throughout my Breck experience. I love science research and this passion stemmed from my interested in robotics. I joined Breck's robotics team my freshman year. I quickly became the captain of the team within 2 years. I led the team in design, manufacturing and programing of the robot. I was also involved in the student diversity club. I presented to students, faculty and administrators about how to make Breck a safer and more socially aware school. Additionally, I tutor kids math skills ranging from basic geometry to advanced trigonometry. Lastly, I play on Breck's Varsity tennis team as a doubles player.
Honors & Awards
Sarah Carlson (2016) & Siddarth Eswarachari (2016) worked in the Biology Department at the University of St. Thomas under the guidance of Dr. Jayna Ditty. Sid and Sarah represented the United States at the International Sustainable World Engineering, Energy, Environment Project Olympiad (ISWEEEP) and were awarded the First Grand Prize Award, a Gold Medal, the Consumer Energy Alliance Award, and the Milset Award. In the Siemens paper competition, they were named regional semifinalists as well. At the regional science fair, they were awarded the Stockholm Junior Water Prize, the 3M Young Inventor Award, and the Glen and Jacob Domeier Memorial Award. At the North Central Junior Science and Humanities Symposium, Sid and Sarah won fifth place overall, advancing to the National Junior Science and Humanities Symposium. They were awarded a First Place Grand Award at the state science fair, as well as the Ecolab Foundation Green Award, the Ricoh Sustainability Award, the Stockholm Junior Water Prize, and the Wolfram Research Mathematica Software Award. Sarah will be attending Case Western Reserve University, and Sid will be attending Carnegie Mellon University.