HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Carlini, C. R. Articles by Polacco, J. C. PubMed Articles by Carlini, C. R. Articles by Polacco, J. C. Agricola Articles by Carlini, C. R. Articles by Polacco, J. C. Related Collections Seed Quality Plant and Soil Interactions Insect Resistance

SCIENTIFIC PERSPECTIVES

Toxic Properties of Urease

^a Dep. of Biophysics and Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Prédio 43.422 - sala 204, Porto Alegre, RS, CEP 91501-970, Brazil
^b Interdisciplinary Plant Group and Dep. of Biochemistry, Univ. of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, and Dep. of Biophysics and Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, CEP 91501-970, Brazil

^* Corresponding author (polaccoj{at}missouri.edu).

Plant ureases have long been known for their ureolytic activities, dependent on a Ni metallocenter active site. We report here on more recently discovered novel toxic properties of ureases—properties independent of enzyme activity. Plant ureases have potent toxicity against insects that are not affected by Bt toxins. Entomotoxicity relies on an internal peptide released by insect digestive enzymes. Plant ureases are fungitoxic—in the absence of ureolytic activity—a property shared with some microbial ureases. We have found that both plant and microbial ureases also induce secretion in animal cells (and thus might be defense and pathogen factors, respectively). We suggest that in the soil, bacterial urease-induced secretion by plant roots may play a role in rhizosphere relationships. While ureases of plant, fungi, and bacteria align with greater than 50% amino acid identity, toxicity and signaling may be due to more divergent domains, such as that for the insecticidal sub-peptide. These domains are potential targets for manipulation to improve plant defense against herbivores and pathogens.

Abbreviations: ED₅₀, 50% effective dose • HPU, Helicobacter pylori urease • JBU, jackbean major seed urease • LD₅₀, lethal dose for 50% of experimental subjects • SBU, soybean embryo-specific urease