Jean-Jacques Macheix

Accumulation of oleuropein derivatives during olive maturation

Abstract Elenolic acid glucoside and demethyloleuropein are glucosylated derivatives of oleuropein which accumulate during olive ( Olea europaea ) maturation. These compounds appear simultaneously with a fall in oleuropein content and an increase in esterase activity. This enzyme may thus be responsible for the formation of the two oleuropein derivatives.

Changes and importance of oligomeric procyanidins during maturation of grape seeds

Abstract Flavans and procyanidins from the seeds of different grape varieties were separated and identified using HPLC techniques. The compounds identified were (+)-catechin and (−)-epicatechin, dimeric procyanidins B1, B2, B3 and B4, trimeric procyanidin C2 and gallic acid. During maturation of the grape berries, the flavan-3-ol content fell in the seeds whereas procyanidin levels increased. This suggests an interrelationship between the compounds. There was also evidence of varietal differences in the amounts of phenolic compounds in grape seeds.

Inoculation of Platanus acerifolia with Ceratocystis fimbriata f. sp. platani induces scopoletin and umbelliferone accumulation

Abstract Umbelliferone and scopoletin were induced in stem of Platanus acerifolia seedlings in response to inoculation with Ceratocystis fimbriata f. sp. platani, the canker stain disease agent. These phenolic compounds were found to be antifungal using bioassays and they therefore can be considered as phytoalexins. Nevertheless, they accumulate too late to totally inhibit conidial germination, thus allowing the parasite to colonize the tissues near the inoculation site.

Enhancement of anthocyanin synthesis and dihydroflavonol reductase (DFR) activity in response to phosphate deprivation in grape cell suspensions

Anthocyanin synthesis occurred early during the culture cycle of grape cell suspensions. Dihydroflavonol reductase (DFR) activity and anthocyanin synthesis were found well correlated within this period. Phosphate deprivation leads to a large enhancement in DFR activity with a maximum which was observed earlier than in control medium. An increase in anthocyanin accumulation was also observed in association with a higher degree of peonidin 3-glucoside acylation.

Accumulation of phytoalexins in leaves of plane tree (Platanus spp.) expressing susceptibility or resistance toCeratocystis fimbriata f. sp.platani

Inoculation of leaves of resistantPlatanus occidentalis and susceptiblePlatanus acerifolia leaves withCeratocystis fimbriata f. sp.platani, the canker stain disease agent, induced foliar necrosis and biosynthesis of two phytoalexins, scopoletin and umbelliferone. Foliar symptoms keep localized and accumulation of coumarin phytoalexins was rapid for incompatible interactions. Necrosis spread widely and accumulation of these phenolic compounds was much later and lower for compatible interactions. The differential response could be used in a genetic improvement program for resistance against canker stain.

Phenolic compounds in date palm cultivars sensitive and resistant toFusarium oxysporum

In date palm (Phoenix dactylifera L.) leaves, the main compounds of the phenolic pool were quercetin and isorhamnetin heterosides, (+)-catechin and (-)-epicatechin. Although previously observed only in date palm fruits, 5-caffeoylshikimic acid (dactylifric acid) and its positional isomers (3-caffeoylshikimic acid and 4-caffeoylshikimic acid) were detected also in the leaves and roots. Quantitative, but not qualitative, differences between cultivars resistant and susceptible toFusarium oxysporum f. sp.albedinis during growth period were observed

Purification of an apple polyphenoloxidase isoform resistant to SDS-proteinase K digestion

Abstract An active proteolysed isoform of apple pulp polyphenoloxidase (PPO) was purified by a very quick three-step method based on its resistance to further sodium dodecyl sulphate-proteinase K digestion. After extraction from a thylakoid membrane pellet and pre-purification by temperature-induced phase partitioning, PPO was subjected to sodium dodecyl sulphate-proteinase K digestion, and then 388-fold to homogeneity purified by DEAE-cellulose column chromatography with a yield greater than 40%. This purified, enzymatically active PPO isoform was used to raise polyclonal antibodies. High titred specific serum was obtained and immunoblots were performed to detect active and latent forms of the enzyme.

Quinyl esters and glucose derivatives of hydroxycinnamic acids during growth and ripening of tomato fruit

Abstract Quinyl esters of hydroxycinnamic acids usually occur in greater abundance than their corresponding glucose esters in tomato fruits. During fruit growth and ripening, the predominant derivatives of hydroxycinnamic acids were found to be chlorogenic acid (76%) and the glucosides (84%) respectively. The variations in the ratio of Benedict-reactive (chlorogenic acid) and non-reactive compounds (mainly caffeic acid glucoside) are discussed in relation to their possible role in the regulation of fruit growth and maturation.

Erratum to: Biosynthesis of phenolic compounds in Vitis vinifera cell suspension cultures: Study on Hydroxycinnamoyl CoA: ligase

In cell suspensions cultures from grape berry pulp (Vitis vinifera cv. Gamay freaux)hydroxycinnamoyl CoA ligase (CoAL) displayed maximum activity (100 %) forp-coumaric acid and then, in decreasing order, for ferulic acid (81.3 %) and caffeic acid (60.4 %). No activity was detected with sinapic and cinnamic acids. The changes in CoAL activity during the growth cycle of the culture displayed two peaks : the highest (6 h after subculturing) was linked with a strong increase in protein caused by dilution ; the second was weaker and occurred on the 7th day of culture.

Tissue compartmentation of phenylpropanoid metabolism in tomatoes during growth and maturation

Abstract Marked changes in the metabolism of hydroxycinnamic acid derivatives were observed in pulp and pericarp of tomato fruit ( Lycopersicon esculentum var. cerasiforme ) during its development. During fruit growth, biosynthesis and accumulation of chlorogenic acid were especially active in the pulp, whereas the formation of glucose derivatives occurred during maturation in the pericarp. There was a clear difference between the two compartments of the fruit concerning hydroxycinnamate: CoA ligase, O -methyltransferase and glucosyltransferase activities. The first two enzymes were high in the pulp during growth and the latter one was high in the pericarp during maturation. Of all the enzymes studied, only the glucosyltransferase showed increasing activity during maturation; it may be considered, along with the glucosylated derivatives, as a biochemical marker of maturation in tomato.