Browsing by Subject "food"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Autoinducer 2-based quorum sensing response of Escherichia coli to sub-therapeutic tetracycline exposure(Texas A&M University, 2006-10-30) Lu, LingengAutoinducer 2 (AI-2) is a quorum sensing signal employed by bacteria to coordinate their response to environmental stresses. The objective of this study was to determine the relationship between presence of AI-2 molecules, exposure to sub-therapeutic tetracycline, the expression of genes associated with the conjugal transfer of antibiotic resistance plasmids, and the conjugal transfer of these plasmids in Escherichia coli. The studies showed that AI-2 activity increased in Tets E. coli in the presence of tetracycline (2 ????g/mL) under both batch and continuous culture conditions. The presence of AI-2 molecules induced tetracycline tolerance development in Tets E. coli. The studies showed that the survival rates of Tets E. coli exposed to AI-2 molecules were significantly higher compared to the cells not exposed to AI-2 molecules or cells that were exposed to only LB (Lauria-Bertani) broth. Molecular analyses using real-time PCR indicate that the expression of at least one conjugation-associated gene (trbC) is increased 9-fold in cells exposed to AI-2 molecules in the presence of sub-therapeutic tetracycline compared to its negative controls. The transconjugation frequency of the plasmid RP4 carrying the tet(A) gene increased between 10-100 fold in the presence of AI-2 molecules. In companion studies, AI-2-like activity was detected in fish, tomatoes, cantaloupes, carrots and milk samples. Interestingly, ground beef and poultry meat contained substances that appear to inhibit AI-2 activity. Collectively, these results highlight the potential importance of bacterial quorum sensing signals such as AI-2 in the response of bacterial cells to environmental stimuli and the possible role of quorum sensing signals in the quality and safety of foods.Item Students' Perceptions of Food and Factors That Influence Purchasing Decisions(2013-06-06) Smith, Lindsay MarieWhen it comes to food, college students need help selecting healthy food choices. Students are presented with many options to purchase food at grocery stores and restaurants and many of these options include organic food. Previous studies have demonstrated a need to investigate the college demographic and their purchasing habits when selecting food. The growth of news television channels, the Internet, magazines, and reality television have given the public a variety of choices to get their information. However, the credibility of their sources is not always trustworthy when it comes to agriculture. The goal of this study was to determine students? perceptions of food and factors that influence purchasing decisions. Texas A&M University U4 classified students in the departments of political science, animal science, biology, and agricultural leadership, education, and communications (n=578) received an online survey. The survey identified students? perceptions of food, the sources of information used to find food, food attributes, and the demographics that influence willingness to pay for food. Students in this study were more knowledgeable than previous studies with 70.4% of students identifying the correct definition of organic and 67% correctly recognized the USDA organic seal. This study also suggests that labels influence their opinion of food and ranked package information as the most important factor when ranking food attributes. Also, the study found that family does influence students? decision to purchase food and celebrities influence student?s students? perceptions of organic food.