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The intravacuolar organic matrix associated with calcium oxalate crystals in leaves of Vitis
Author(s) -
Webb Mary Alice,
Cavaletto John M.,
Carpita Nicholas C.,
Lopez Linda E.,
Arnott Howard J.
Publication year - 1995
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1995.7040633.x
Subject(s) - biomineralization , chemistry , calcium oxalate , matrix (chemical analysis) , oxalate , nucleation , phase (matter) , crystal (programming language) , calcium , crystallography , chemical engineering , chromatography , inorganic chemistry , organic chemistry , computer science , programming language , engineering
Summary In Vitis (grape) calcium oxalate crystals form in a needle‐like morphology unique to plants, presenting an intriguing system of biological control over mineral formation. Crystals develop within an organic matrix which appears to provide control over the sites and forms of crystal deposition; however, little is known about the chemical nature of the matrix. A procedure has been developed to isolate crystals along with their associated intravacuolar matrix from leaves of grape, and studies have been initiated into the chemical composition of the matrix by characterizing elemental content, carbohydrates, and protein. The isolated matrix consisted of two structural phases, membrane chambers enclosing developing crystals, and a water‐soluble phase surrounding the crystal chambers. Elemental analysis detected substantial calcium and potassium, as well as some iron in the water‐soluble phase. Analysis of the water‐soluble matrix by GC‐MS showed that it contained an unusual polymer with novel glucuronic acid linkages. In addition, linkage analysis indicated 5‐linked arabinans, arabinogalactan, and various mannosyl units typical of complex carbohydrates of N‐linked glycoproteins. SDS—PAGE analysis of the water‐soluble matrix and crystal chambers showed that each had distinct banding profiles in silver‐stained gels, with prominent 60 and 70 kDa polypeptides in crystal chamber extracts. Demineralization studies provided direct evidence that the isolated matrix promotes crystal nucleation. The findings about the organic matrix associated with calcium oxalate crystals in grape are discussed in relation to crystal nucleation and growth and features shared with animal and microbial biomineralization systems.