Yu (Alice) Gao

Institute of Marine and Coastal Sciences

Rutgers University

New Brunswick, NJ 08903-0231

Phone: 730-932-8165x327 e-mail: gao@aesop.rutgers.edu

Education:

Ecophysiology and molecular biology of phytoplankton; Nitrogen and Sulfur metabolism; Environmental regulation of primary productivity in aquatic ecosystem; Role of phytoplankton in globe nitrogen and sulfur cycling; Application of molecular probes (in situ & in vitro) in oceanographic studies.

The following colleagues have agreed to provide letters in support of Yu (Alice) Gao:

My research interests focus on using an approach that integrates molecular biology, biochemistry and physiology to address oceanographic questions and environmental issues, because I think that understanding subcellular and molecular features of marine organisms is a critical step in obtaining mechanistic understanding of the biological processes in the ocean, an ultimate goal of biological studies in the ocean. These interests are evident throughout my past research activities, which can be briefly summarized as follows:

1) Nitrate Assimilation in the Marine Diatom Skeletonema costatum:

As the major pathway by which marine phytoplankton acquires N from environment, nitrate assimilation was investigated by targeting a key component, nitrate reductase (NR), in the pathway. This enzyme catalyzes the reduction of nitrate to nitrite and has been identified as a rate limiting and key regulatory site in nitrate assimilation. Therefore, the biochemical and regulatory features of NR from a common marine diatom, Skeletonema costatum, were studied. In addition, the applicability of NR abundance as an index for estimating new production was explored.

Biochemical characterization using both purified NR and cell-free extracts revealed several unique features of the enzyme quite distinct from vascular plant NRs. The features included the molecular mass of native enzyme, heavy metal sensitivities of the activity and temperature dependence of the enzyme activity and abundance. The polyclonal antibodies generated against purified diatom NR were demonstrated to be specific for diatoms. The antigenicity of NRs from marine phytoplankton are divergent. These features alone provided significant insights and entrees into the central role of NR in controlling the production dynamics of phytoplankton in the ocean.

Environmental impacts on the initial events in nitrate assimilation (nitrate transport and reduction) were investigated by monitoring NR activities, NR protein abundance and internal nitrate levels determined by a rapid method developed in this research. The results demonstrated the independent environmental controls on nitrate transport and reduction. Long-term exposure to ammonium completely eliminates nitrate assimilation capacity. However, induction of nitrate transport and reduction capacities by nitrate and light is rapid, requires both light and nitrate, and involves de novo synthesis of NR protein and a nitrate transport system. Further, it is concluded that internal nitrate and redox state associated with photosynthetic electron transport may provide a regulatory signal essential for the induction. It was also demonstrated that ammonium inhibition of nitrate assimilation is at the level of nitrate transport rather than nitrate reduction and that ammonium and nitrate assimilation can occur concomitantly providing that internal nitrate pools are adequate.

The use of antibodies to detect NR protein in intact phytoplankton cells and to trace NR abundance in response to environmental shifts were explored. It was demonstrated that NR protein is not constitutively expressed, its abundance is sensitive to environmental shifts, and it may serve as a better index than in vitro activity for estimating nitrate assimilation potential. Further, a protocol for in situ detection of NR was developed, which allows for detecting NR protein in individual cells by flow cytometry and resolving fine scale dynamics of NR protein abundance in response to environmental transitions.

This research has not only significantly advanced our understanding of the underlying biological mechanisms that control the production dynamics of marine phytoplankton, but has also opened a variety of research opportunities in NR biochemistry, phylogeny, eco-physiology and molecular biology. In addition, this investigation demonstrated the significance of biochemical and molecular approaches and subcellular features of marine organisms for obtaining mechanistic understandings of biological processes in the ocean.

2) DMSP Production and Sulfate Assimilation in Marine Algae:

Currently, investigation continues regarding further characterization of these enzymes, cloning the genes encoding these enzyme and environmental impact on the regulation of these enzymes. The research will not only provide mechanistic understanding about the role of environmental factors on DMSP production, but will also advance our general understanding of sulfur physiology in marine phytoplankton because DMSP biosynthesis is an important part of cellular sulfur metabolism. This is an area that holds significant promise for biotechnological exploitation, yet an area that little is known. In addition, since DMSP biosynthesis involves the consumption of sulfur-containing amino acid and very likely recycling of nitrogen, this study will yield insights into the coupling of nitrogen and sulfur metabolisms in marine algae under environmental stresses. .

I plan to continue my research on the molecular biology, biochemistry and eco-physiology of biological processes in the ocean. I think that it is important to understand subcellular and molecular features of marine autotrophs, not only because it will help us to understand how marine organisms function in molecular terms (the fundamental biological mechanism), but also because it will lay theoretically framework for oceanographic field studies and enhance our ability of prodicting and modeling. The research is also challenging because of the great diversity of marine autotrophs, the lack of current knowledge about the subcellular and molecular features of these organisms, the intrinsic technical difficulties involved in relevant researches and the current lack of expertise in the community. Further, such research is interdisciplinary and a crucial part for biotechnology development in the ocean, therefore, promotes collaborative adventures and may attract industry fundings.

Throughout my academic and scientific career, I have always found teaching a very challenging and extremely rewarding activity. I am committed to quality undergraduate and graduate education employing multi-disciplinary methods in lecture and hands-on laboratories. I am an experienced speaker and am comfortable with both large and small audiences.

Teaching Philosophy: Education is a process which provides opportunities to expand and extend knowledges for the continued growth of individuals and the profession. Biology is uniquely challenging because it is a multi-disciplinary science. Therefore, the education must be carefully organized to expand the knowledge, skill, and attitudes in preparation of the student's career. My function as a teacher is to inspire the students and to assist them in assimilating and organizing knowledge while also providing the practical scientific skills. My teaching style is to interface basic fundamental knowledge and theories with cutting-edge techniques, so that students will not only be equipped with the theoretical background but also be given the technical experiences and confidence to pursue a career in the sciences. I believe that the material should be heavily grounded in the primary literature whenever possibly so that the students can see that science is dynamic and continually evolving. My hope is that students might realize that scientific endeavors are not "cut-and dry" and require a great deal of creative effort.

Teaching experiences: I was a teaching assistant in graduate school at University of Southern California for a year, where I taught introductory laboratory biochemistry and molecular biology for undergraduate students. These laboratories required teaching assistants to give a short lecture before labs so that the students understand the principles and applications. I was also a teaching assistant for the laboratory portion of Ecophysiology and Molecular Biology of Macrophytes at Hopkins Marine Station of Stanford University. This course was a graduate level course and all laboratories were hands-on classes requiring students not only to learn how to apply modern techniques in molecular biology and biochemistry to address ecological questions but also to design, collect, analyze and write up their findings in manuscript form. In addition, I participated as a mentor in the leadership program in environmental sciences sponsored by the Woodrow Wilson National Fellowship Foundation, and had worked as a volunteer guide at Monterey Bay Aquarium. Often the graduate students act as mentors and provide training for undergraduate student. I was the graduate advisor for several undergraduates and provided the technical training for their projects. More importantly, I was able to act as a counselor to these students. Some of the students I have supervised have continued onto graduate schools, several others are now full-time technicians in marine biology related field.

Teaching interests: I am interested in developing courses that take the advantage of my strengths and research interests and yet provide student with a fundamental understanding of the basic biology of marine autotrophs and an appreciation for the relevance of this information to their own interests, both as scientists and as members of the larger human society.

I feel qualified to teach MARINE BIOLOGY, BIOLOGICAL OCEANOGRAPHY, ECO-PHYSIOLOGY OF PHYTOPLANKTON AND/OR MACROPHYTES, and technical courses/laboratories in biochemistry and molecular biology of marine autotrophs.

In addition, I would like to lead and participate in seminars on advanced topics related to ecophysiology of marine autotrophs and molecular and biochemical approaches to oceanographic questions and environmental issues.