title: Asparagine in plums detected by CEST-MRI.
abstract: Magnetic resonance imaging (MRI) relies on the topological distribution of the intense water NMR signal and may be used to report about changes in the internal structures of fruits associated to ripening, storing, pathogen infection. Herein the use of CEST-MRI (chemical exchange saturation transfer) is introduced to show that in addition to structural information, insights into the presence in the fruits of specific chemicals may be gained. Asparagine is present in plums at relatively high concentration (≈10-20mM) and owns two amide protons (at 2.1 and 2.8ppm down field from water) in slow exchange with water protons. By irradiating the amide resonances with a proper rf-field it is possible to transfer saturated magnetization to the "bulk" water signal. The attained change in signal intensity reflects the extent of prototropic exchange between amide and water protons that is modulated by the local pH.
authors.affiliation: Center of Competence for the Innovation in the Agro-Environmental Sector (AGROINNOVA), University of Torino, Via Leonardo da Vinci, 44, 10095 Grugliasco, Torino, Italy.
authors.forename: Rachele
authors.initials: R
authors.lastname: Podda
authors.affiliation: Department of Molecular Biotechnology and Health Sciences, Molecular Imaging and Preclinical Centers, University of Torino, Torino, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Delli Castelli
authors.affiliation: DISIT, Università del Piemonte Orientale "A. Avogadro", Via T. Michel 11, 15121 Alessandria, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Digilio
authors.affiliation: Center of Competence for the Innovation in the Agro-Environmental Sector (AGROINNOVA), University of Torino, Via Leonardo da Vinci, 44, 10095 Grugliasco, Torino, Italy.
authors.forename: Maria Lodovica
authors.initials: ML
authors.lastname: Gullino
authors.affiliation: Department of Molecular Biotechnology and Health Sciences, Molecular Imaging and Preclinical Centers, University of Torino, Torino, Italy. Electronic address: silvio.aime@unito.it.
authors.forename: Silvio
authors.initials: S
authors.lastname: Aime
mesh_terms: D001216:Asparagine / Q000032:analysis*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011522:Protons; D027861:Prunus / Q000737:chemistry*
chemical_list: D011522:Protons; D001216:Asparagine
keywords: Asparagine; CEST; MRI; Plum; Ripening