Selenium Homeostasis in Stenotrophomonas Maltophilia ORO2 and E. coli

从田纳西州橡树岭的一条重金属污染的溪流中分离到嗜麦芽窄食单胞菌。该菌株显示了沉淀亚硒酸盐的能力，亚硒酸盐是一种无机形式的硒。硒是所有生物必需的微量元素，但暴露在高浓度的亚硒酸盐中可能是致命的。这项研究将集中在耐硒细菌在接触到有毒水平的亚硒酸盐时处理硒的能力。将嗜麦芽窄食单胞菌O2基因转移到一株常见的实验室菌株中，并对其进行了亚硒酸盐抗性的鉴定。将使用蛋白质组学来研究抗药性的机制，以检测在特定生长条件下表达的蛋白质总数。耐亚硒的嗜麦芽窄食单胞菌O2和大肠杆菌将在两种不同的培养方式中生长，一种是含有亚硒酸盐中毒水平的菌株，另一种是不含亚硒酸盐的菌株。在每种条件下生长的细菌的蛋白质将被分离出来，并使用二维凝胶电泳法进行分离。两种凝胶中斑点的强度将显示哪些蛋白质在亚硒酸盐存在时比在没有亚硒酸盐时更丰富。这些斑点中的蛋白质随后将使用质谱学技术进行鉴定。通过鉴定和研究在高浓度亚硒酸盐存在下表达的蛋白质，将有可能了解细菌中的硒稳态(硒摄取和硒解毒的平衡)。这项研究的结果也可能对硒作为抗氧化剂的作用提供洞察力。这个项目的更广泛的教育影响将是巨大的。这项研究将介绍扬斯敦早期学院(YEC)项目中代表性不足的少数民族学生(该项目中73%的学生是代表性不足的少数民族)进入科学职业生涯，并为扬斯敦2010年的教育重点做出贡献，这是一项复兴该市艺术、医疗保健、政府和教育的计划。YEC是扬斯敦市学区与扬斯敦州立大学合作的一个项目，为贫困高中生提供在大学环境中接受高中教育的机会。虽然这些学生可以在校园里学习一些大学课程，但他们没有机会在研究实验室工作。YEC的学生将被邀请参加有关亚硒酸盐抗性的研究项目。

Stenotrophomonas maltophilia ORO2 (S. maltophilia O2) was isolated from a heavy metal contaminated stream in Oak Ridge, TN. This strain demonstrated the ability to precipitate selenite, an inorganic form of selenium. Selenium is an essential trace element for all living organisms, but exposure to high concentrations in the form of selenite can be lethal. This research will focus on the ability of selenite resistant bacteria to process selenium when exposed to toxic levels of selenite. A S. maltophilia O2 gene, which may be involved in selenite resistance, was transferred to and conferred selenite resistance in a common laboratory strain of Escherichia coli (E. coli). Mechanisms of resistance will be studied using proteomics to examine the total number of proteins expressed under certain growth conditions. Selenite resistant strains of S. maltophilia O2 and E. coli will be grown in two different cultures, one with toxic levels of selenite and the other without selenite. Proteins from bacteria grown under each condition will be isolated and separated using 2-dimensional gel electrophoresis. The intensity of spots in the two gels will show which proteins are more abundant in the presence of selenite than in its absence. The proteins in the spots will then be identified using a mass spectrometry technique. By identifying and studying proteins expressed in the presence of high selenite concentrations, it will be possible to understand selenium homeostasis (a balance of selenium intake with selenium detoxification) in bacteria. Results from this research may also provide insights into the role of selenium as an antioxidant.The broader educational impact of this project will be tremendous. This research will introduce underrepresented minority students in the Youngstown Early College (YEC) program (seventy-three percent of the students in this program are underrepresented minorities) to a career in science and contribute to the educational focus of the Youngstown 2010, a plan to revive the arts, health care, government, and education of the city. The YEC is a program in which the Youngstown city school district collaborates with Youngstown State University to provide underprivileged high school students with the opportunity to receive their high school education in a university setting. While these students have access to some of the college courses on campus, they do not have the opportunity to work in research laboratories. YEC students will be invited to participate in the research project on selenite resistance.