Giuseppe Dalessandro

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Membrane fractions and digitonin-solubilized enzymes prepared from stem segments isolated from the third internode of etiolated pea seedlings (Pisum sativum L. cv. Alaska) catalyzed the synthesis of a β-1,4-[su14C]mannan from GDP-d-[U-14C]-mannose, a mixed β-1,3- and β-1,4-[14C]glucan from GDP-d-[U-14C]-glucose and a β-1,4-[14C]-glucomannan from both(More)
Many fruits, including watermelon, are proficient in carotenoid accumulation during ripening. While most genes encoding steps in the carotenoid biosynthetic pathway have been cloned, few transcriptional regulators of these genes have been defined to date. Here we describe the identification of a set of putative carotenoid-related transcription factors(More)
Fourteen cultivars of cherry tomatoes and four cultivars of high-pigment tomato hybrids were cultivated in southern Italy, and the red-ripe fruits were analyzed for their content in different classes of antioxidants and for their antioxidant activity. Among the different cultivars, significant differences were found between lycopene, beta-carotene,(More)
The regulatory functions of Rab proteins in membrane trafficking lie in their ability to perform as molecular switches that oscillate between a GTP- and a GDP-bound conformation. The role of tomato LeRab11a in secretion was analyzed in tobacco protoplasts. Green fluorescent protein (GFP)/red fluorescent protein (RFP)-tagged LeRab11a was localized at the(More)
The sub-cellular feruloylation and oxidative coupling sites of cell wall polysaccharides were investigated in planta by monitoring the kinetics of appearance of arabinosyl- and feruloyl-radiolabelled polysaccharides in the protoplasmic compartment and their secretion in the wall either in the presence or absence of brefeldin A (BFA). By using root apical(More)
A protein fraction [precipitate obtained between 40 and 65% (NH4)2SO4 satn.] prepared from cambial cells, differentiating xylem cells and differentiated xylem cells of pine and fir trees contained all the enzymes required for the nucleoside diphosphate sugar interconversions. By using UDP-D-[U-14C]glucose or UDP-D-[U-14C]galactose, UDP-D-[U-14C-]glucuronic(More)
Particulate membrane preparations have been isolated from cambial cells, and from differentiating and differentiated xylem cells of the main stem of pine trees. These preparations synthesise a β1→4 glucomannan from guanosine 5′-diphosphate-mannose. The polysaccharide and the synthase have been characterized and the Km and Vmax for the synthase determined as(More)
The secretory pathway in plants involves sustained traffic to the cell wall, as matrix components, polysaccharides and proteins reach the cell wall through the endomembrane system. We studied the secretion pattern of cell-wall proteins in tobacco protoplasts and leaf epidermal cells using fluorescent forms of a pectin methylesterase inhibitor protein(More)
The building up of the cell wall is tightly dependent on the functionality of the secretory pathway. Syntaxins as well as other SNARE proteins play important roles during vesicle secretion and fusion. We have compared the secretion of newly synthesised cell-wall polysaccharides to that of secretory marker proteins such as secreted green-fluorescent protein(More)
The in vivo effect of Brefeldin A (BFA) on the synthesis and transport of cell wall polysaccharides and proteins in the roots of pea seedlings (Pisum sativum L. cv. Alaska) was investigated. BFA (10 //gml") inhibited the synthesis of cell wall matrix polysaccharides by approximately 43%. Under the same conditions, cellulose synthesis was inhibited by(More)