Pedro Marcos Civello

Learn More
Tissue softening accompanies the ripening of many fruit and initiates the processes of irreversible deterioration. Expansins are plant cell wall proteins proposed to disrupt hydrogen bonds within the cell wall polymer matrix. Expression of specific expansin genes has been observed in tomato (Lycopersicon esculentum) meristems, expanding tissues, and(More)
Fleshy fruit soften during ripening mainly as a consequence of solubilization and depolymerization of cell wall components. We have performed a comparative study of the polysaccharide content of fruit cell walls during final steps of development and ripening of three strawberry (Fragaria x ananassa Duch.) cultivars with different softening rates. The three(More)
Degradation of chlorophylls during senescence is a highly regulated process which requires the concerted action of several enzymes. Traditionally, it has been stated that the dismantling process of the chlorophyll molecule begins with a dephytilation step, followed by Mg(2+) removal and other breakdown reactions. Recently, new evidence suggests the(More)
Fruit softening is associated with cell wall disassembly mediated by the action of a complex set of enzymes and proteins. Expansins, a group of proteins with unknown enzymatic activity, are proposed to be involved in this process. In order to study the involvement of expansins in strawberry fruit softening we have analyzed the expression level of five(More)
A putative carbohydrate binding module (CBM) from strawberry (Fragaria × ananassa Duch.) expansin 2 (CBM-FaExp2) was cloned and the encoding protein was over-expressed in Escherichia coli and purified in order to evaluate its capacity to bind different cell wall polysaccharides “in vitro”. The protein CBM-FaExp2 bound to microcrystalline cellulose, xylan(More)
Several cell wall enzymes are carbohydrate active enzymes that contain a putative Carbohydrate Binding Module (CBM) in their structures. The main function of these non-catalitic modules is to facilitate the interaction between the enzyme and its substrate. Expansins are non-hydrolytic proteins present in the cell wall, and their structure includes a CBM in(More)
Peroxidase (POX) from strawberry fruits was analyzed for its capacity to bleach chlorophyll. The partially purified enzyme preperation catalyzed the bleaching of chlorophylls and their derivatives in the presence of H(2)O(2) and phenolic compounds. The optimal reaction conditions were 35 degrees C, pH 5.2 and ionic strength equal to 0.2. The maximum(More)
Strawberry fruit shows a marked softening during ripening and the process is associated with an increment of pectin solubility and a reduction of the molecular mass of hemicelluloses. In this work, we report the activity of beta-xylosidase and the expression of a beta-xylosidase gene in strawberry fruit. We have cloned a cDNA fragment encoding a putative(More)
The removal of Mg2+ is an important step in the chlorophyll degradation pathway and extracts from senescent and presenescent Arabidopsis thaliana leaves were analyzed for Mg-dechelatase activity, using chlorophyllin, an artificial derivative of the natural substrate, chlorophyllide. The optimum temperature and pH for this reaction were determined to be at(More)
A postharvest treatment with hot air (48 C during 3 h) was applied to fresh-cut broccoli to investigate its effect on quality and senescence during storage at 0 C. The treatment delayed yellowing as evidenced by lower decrease of Hue values during storage. After 21 days of storage, treated broccoli had chlorophyll content approximately 40% higher than(More)