Biochemistry

Joseph C. Polacco

Professor Emeritus of Biochemistry

E-mail:polaccoj@missouri.edu

Mail: Biochemistry
117 Schweitzer Hall
University of Missouri
Columbia, MO 65211

Phone: 573-882-4845

Fax: 573-882-5635

Lab: 573-882-9940

Educational background

Notable honors and service

• Fulbright Research Awards (2000, 2005)

Research description

Joe Polacco, as an Emeritus Professor, has ‘de-emphasized’ research somewhat, but retains ties with labs in Europe and South America. He co-advises visiting students from Brazil (e.g. Ströhm et al. 2012), and pursues his long-standing interest in Ni activation (Polacco et al. 2011) of plant (mainly soybean) ureases. Ni role in plant metabolism in general remains an interest (Mazzafera et al. 2012), esp. in the economically important coffee tree.

Polacco has redefined his focus on urease roles in plant nitrogen metabolism (Polacco and Todd, 2011) to the defense roles (insecticidal, inflammatory, and fungitoxic) of urease (Carlini and Polacco 2008). Understanding the first two roles was the aim of a Mizzou Advantage Undergraduate Research Team project in which Polacco, Dr. Gary Weisman (Biochemistry) and Dr. Qisheng Song (Entomology), directed a 6-member undergraduate research team over the 2011/12 academic year to examine these properties. Intact Helicobacter pylori urease was found to work through the P2Y₂R signaling pathways stimulating intracellular Ca²⁺ mobilization and mitogen-activated protein kinase (MAPK) activation in cultured astrocytes. The insecticidal effect of a specific urease sub-peptide is still being tested in Drosophila, an insect that lacks the gut cathepsins that release this peptide in urease-sensitive insects. If Drosophila proves sensitive, it will be subjected to genetic manipulation to identify the peptide’s target and mode of action.

Activities and Teaching

Polacco is the Project Director of Missouri EPSCoR (Experimental Program to Stimulate Competitive Research) program of the National Science Foundation. EPSCoR can provide funding to Missouri as a whole to improve its research infrastructure, and to facilitate STEM education, workforce training and science outreach state-wide. Polacco is head of the Missouri EPSCoR governing board which is currently assembling infrastructure improvement “white papers” from the state to incorporate in a proposal to be submitted in late 2012 or early 2013.

Polacco teaches a section in the Biochemistry capstone course for seniors. In the past year he has been a member of the Organizing Committee of the Annual Symposium of the MU Interdisciplinary Plant Group.

Selected publications

Mazzafera P, Tezotto T, Polacco JC Roles of Ni in plants. Encyclopedia of Metalloproteins (SL Ciurli, ed) 2012;In press. Springer, Berlin.

Wiebke-Ströhm B, Pasquali G, Margis-Pinheiro M, Bencke M, Bücker-Neto L, Becker-Ritt AB, Martinelli AHS, Rechenmacher C, Polacco JC et al. Ubiquitious urease affects soybean susceptibility to fungi. Plant Molecular Biology 2012;DOI: 10.1007/s11103-012-9894-1

Polacco JC, Hyten DL, Medeiros-Silva M, Sleper DA, Bilyeu KD (2011) Mutational analysis of the major soybean UreF paralogue involved in urease activation. Journal of Experimental Botany 2011;62: 3599–3608.

Environtmental Aspects of Nitrogen Metabolism in Plants. (JC Polacco, CD Todd, eds.) 2011 Wiley-Blackwell

Tovar-Mendez A, Todd CD and Polacco JC. The mitochondrial connection: Arginine degradation versus arginine conversion to nitric oxide. Plant Signaling and Behavior 2008;3:1106-1108.

Flores T, Todd CD, Tovar-Mendez A, Dhanoa PK, Correa-Aragunde N, Hoyos ME, Brownfield DM, Mullen RT, Lamattina L and Polacco JC. Arginase-negative mutants of Arabidopsis exhibit increased nitric oxide signaling in root development. Plant Physiology 2008;147(4):1936-1946.

Carlini CR and Polacco JC. Toxic properties of urease. Crop Science 2008;48(5):1665-1672.

Bilyeu KD, Zeng P, Coello P, Zhang ZJ, Krishnan HB, Bailey A, Beuselinck PR and Polacco JC. Quantitative conversion of phytate to inorganic phosphorus in soybean seeds expressing a bacterial phytase. Plant Physiology 2008;146(2):468-477.

Todd, CD, Tipton P, Blevins DG, Pineda M, Piedras P, Polacco JC (2006) Update on ureide degradation in legumes. Journal of Experimental Botany 2006;57: 5-12

Lombardo MC, Graziano M, Polacco JC, Lamattina L Nitric oxide functions as a positive regulator of root hair development. Plant Signaling & Behavior 2006;1: 28-33

Todd CD, Polacco JC AtAAH, an allantoate amidohydrolase from Arabidopsis thaliana. Planta 2006;223: 1108 - 1113

Palmieri L, Todd CD, Arrigoni R, Hoyos ME, Santoro A, Polacco JC (2006) Arabidopsis mitochondria have two basic amino acid transporters with partially overlapping specificities and differential expression in seedling development. Biochimica et Biophysica Acta 2006;1757: 1277-1283