title: Beetroot-pigment-derived colorimetric sensor for detection of calcium dipicolinate in bacterial spores.
abstract: In this proof-of-concept study, we describe the use of the main red beet pigment betanin for the quantification of calcium dipicolinate in bacterial spores, including Bacillus anthracis. In the presence of europium(III) ions, betanin is converted to a water-soluble, non-luminescent orange 1∶1 complex with a stability constant of 1.4 × 10(5) L mol(-1). The addition of calcium dipicolinate, largely found in bacterial spores, changes the color of the aqueous solution of [Eu(Bn)(+)] from orange to magenta. The limit of detection (LOD) of calcium dipicolinate is around 2.0 × 10(-6) mol L(-1) and the LOD determined for both spores, B. cereus and B. anthracis, is (1.1 ± 0.3)× 10(6) spores mL(-1). This simple, green, fast and low cost colorimetric assay was selective for calcium dipicolinate when compared to several analogous compounds. The importance of this work relies on the potential use of betalains, raw natural pigments, as colorimetric sensors for biological applications.
authors.affiliation: Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, SP, Brazil.
authors.forename: Letícia Christina Pires
authors.initials: LC
authors.lastname: Gonçalves
authors.forename: Sandra Maria
authors.initials: SM
authors.lastname: Da Silva
authors.forename: Paul C
authors.initials: PC
authors.lastname: DeRose
authors.forename: Rômulo Augusto
authors.initials: RA
authors.lastname: Ando
authors.forename: Erick Leite
authors.initials: EL
authors.lastname: Bastos
mesh_terms: D001408:Bacillus anthracis / Q000502:physiology*; D027461:Beta vulgaris / Q000737:chemistry*; D003124:Colorimetry / Q000295:instrumentation*; D057230:Limit of Detection; D010848:Picolinic Acids / Q000032:analysis*; D018517:Plant Roots / Q000737:chemistry*; D013171:Spores, Bacterial / Q000737:chemistry*
chemical_list: D010848:Picolinic Acids; C004860:dipicolinic acid
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