Cyanobacteria are important organisms that live in diverse habitats. They get their energy from sunlight, their carbon from carbon dioxide in the air, and their nitrogen from the nitrogen gas in the air. They are important not only as free-living organisms, but also as partners in many symbiotic associations with plants and fungi. Anabaena is a cyanobacterium of great interest for its ability to convert nitrogen gas in the air to fertilizer by a process called nitrogen fixation. Anabaena, one of the best studied cyanobacteria, grows photosynthetically in the light, consuming the greenhouse gas, carbon dioxide, and it can grow in the dark using sugar as both a carbon and energy source. It grows well with nitrogen sources such as nitrate or ammonia, but it can also convert atmospheric nitrogen to ammonia, a form usable by plants. In addition to ammonia, the enzyme nitrogenase naturally produces hydrogen, an alternative energy source, and Anabaena has been used for the production of hydrogen in outdoor bioreactors. This conversion of atmospheric nitrogen to ammonia and hydrogen takes place in specialized cells called heterocysts, which contain the necessary enzyme, nitrogenase. The mechanism by which environmental factors control heterocyst differentiation, nitrogen fixation, and hydrogen production in Anabaena is poorly understood. Little is known about the control of expression of the important genes, especially nitrogenase, that are required to fix nitrogen. The goal of this research project is to use genetic tools to better understand the molecular mechanisms by which expression of nitrogenase genes is controlled in Anabaena. The significance of this research is that it can lead to increased nitrogenase activity that could be used for biological fertilizer production. Increased nitrogenase activity would also lead to increased hydrogen production in Anabaena. Thus, this research has the potential to decrease reliance on fossil fuel consumption in the commercial production of fertilizer and to provide hydrogen, which can be used an alternative to gasoline in cars equipped with fuel cells.
This research project is heavily integrated with education. A diverse group of about a dozen undergraduate students will contribute to the research project as part of a structured undergraduate research course that meets two afternoons a week in a teaching laboratory. The course, which has been taught previously, integrates collaborative research with bioinformatics activities, the development of scientific writing skills, and the presentation of the research at the university's Undergraduate Research Symposium. Additional undergraduate research students, graduate students and a postdoctoral fellow will be also be directly involved in the project, working in the research lab. They will work collaboratively on aspects of the work that seek to better understand the regulation of nitrogenase gene expression in heterocysts. Members of the research team will also participate in education outreach activities, especially focused on precollege teachers, to increase their understanding of science in general and microbiology in particular. These activities include development of hand-on activities suitable for the classroom and presentations of these materials at summer workshops for teachers in the St. Louis region. These activities form the basis for educational materials that are distributed freely via the internet.
