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Plant Biology Home

Phone: (612) 625-1234
Fax: (612) 625-1738

Department of Plant Biology
University of Minnesota
250 Biological Science Center
1445 Gortner Ave.
St. Paul, MN 55108

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Florence K. Gleason

Professor, Department of Plant Biology
Ph.D., University of Iowa, 1971

Physiological function of thioredoxin in cyanobacteria

Contact Information

Mailing Address:

Dr. Florence Gleason
Department of Plant Biology
University of Minnesota
250 Biological Science Center
1445 Gortner Ave.
St. Paul, MN 55108

Office: 826 Biological Sciences Center
Phone: 612-625-4275
Fax: 612-625-1738
E-mail:iqa6016@umn.edu

PBio 4601: Topics in Plant Biochemistry
3 credits
 
Topic prereq - BIOL 1002 or BIOL 1009, CHEM 2301

MEETS: 8:45 a.m. - 10:00 a.m., Tu, Th
ROOM 257, BIOLOGICAL SCIENCES CENTER, ST. PAUL

Biomedical analysis of processes unique to photosynthetic organisms. Topics covered include photosynthesis and carbon dioxide fixation. Emphasis placed on synthesis of carbohydrates, lipids and derivatives, aromatic compounds such as lignin and other natural products. Functions of natural products will be discussed.

Pre-requisites for the course are general biology and chemistry, Grading will be done on an A-F basis.   Grades will be determined by written exams and discussions/short written reports of   papers from the scientific literature.

For additional information, contact Prof. Florence K. Gleason, Dept. of Plant Biology
Phone:   625-4275
E-mail:   iqa6016@umn.edu

Research Interests

Thioredoxin is a small, disulfide-containing redox protein. Chloroplasts and cyanobacteria contain two, dissimilar thioredoxins. These both function as protein disulfide reductases. Their status (oxidized or reduced) is determined by the redox state of the cell. The thioredoxins, in turn, transfer this ñredox signalî to enzymes and other proteins and thus regulate their activities in coordination with general cellular metabolism. We have determined that thioredoxins play an essential role in glucose catabolism and ribonucleotide reduction in cyanobacteria. These two functions are now being explored by over-expression of the genes for glucose-6-phosphate dehydrogenase and ribonucleotide reductase from the cyanobacterium, Anabaena sp. PCC 7120. Protein function will be characterized by a study of reaction mechanisms and site-directed mutagenesis.

My lab is also interested in natural products from cyanobacteria and the aquatic angiosperm, Eurasian water milfoil. Eurasian milfoil grows to nuisance levels in many American lakes. We have found that it produces a low molecular weight compound that acts as an attractant to an insect which preferentially feeds and reproduces on the plant and is a potential biocontrol agent. We are now isolating and chemically characterizing this natural product. Further work is planned on its physiological function. This work is being done in collaboration with Professor Ray Newman, Dept. of Fisheries and Wildlife. We have also started a project to explore the distribution of algicidal and antibiotic natural products produced by freshwater cyanobacteria.

Selected Publications

Marko, M.D., Newman, R.M., Gleason, F. K. (2005) Chemically mediated host-plant selection by the milfoil weevil: a freshwater insect-plant interaction. J. Chem. Ecol.31:2857-2876.

Gleason, F.K. and Olszewski, N.E. (2002) Isolation of the gene for the B12-dependent ribonucleotide reductase from Anabaena sp. PCC 7120 and expression in Escherichia coli, J. Bacteriol., 184, #23, p. 6544-6550.

Lee, E-S.J., and Gleason, F.K. (1994) A second algicidal natural product from the cyanobacterium, Scytonema hofmanni, Plant Science, 103:155-160.