References of "Dommes, Jacques"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailComparison of plant defense elicitor properties of amphiphilic compounds from plant-associated bacteria
Mariutto, M.; Fernandez, O.; Thonart, Philippe ULg et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2013), 89

Detailed reference viewed: 47 (14 ULg)
Full Text
Peer Reviewed
See detailExtraction conditions can greatly influence antioxidant capacity assays in plant food matrices
Michiels, Jean-Albert ULg; Kevers, Claire ULg; Pincemail, Joël ULg et al

in Food Chemistry (2012), 130

The estimated antioxidant capacity of different matrices can vary considerably between research reports. Besides intrinsic factors (not studied here), our work showed that may have various causes. Firstly ... [more ▼]

The estimated antioxidant capacity of different matrices can vary considerably between research reports. Besides intrinsic factors (not studied here), our work showed that may have various causes. Firstly, different methods are used to measure antioxidant capacity. Secondly, the results obtained for a single matrix by one method (such as ORAC) can vary with the extraction conditions. Parameters having a great impact on the amount and composition of antioxidants in extracts, and thus on the measured antioxidant capacity, notably include the extraction solvent composition, temperature, extraction time (duration), solvent-to-solid ratio, and storage conditions. Standardization of the extraction procedure is thus necessary for accurate and reproducible determination of the antioxidant capacity and phenolics in different food matrices by different laboratories. In this study we optimised such a procedure for four fresh plant matrices (orange, apple, leek, and broccoli). The optimised procedure requires extraction in a mixture of acetone/water/acetic acid (70/28/2, v/v/v) for 1 h at 4°C, with a solvent-to-solid ratio of 20 mL per 1 g. Fresh material should be used, but if this is not possible, one may lyophilise the plant matrices or store the extracts for a few days at -20°C before analysis. [less ▲]

Detailed reference viewed: 201 (16 ULg)
Full Text
Peer Reviewed
See detailAntioxidant and anti-inflammatory activities of Ribes nigrum extracts.
Tabart, Jessica ULg; Franck, Thierry ULg; Kevers, Claire ULg et al

in Food Chemistry (2012), 131(4), 1116-1122

Blackcurrant berries contain high amounts of flavonoids with various health benefits as anti-inflammatory properties attributed to their antioxidant potential. Leaves and buds actually used to produce ... [more ▼]

Blackcurrant berries contain high amounts of flavonoids with various health benefits as anti-inflammatory properties attributed to their antioxidant potential. Leaves and buds actually used to produce food supplement could also exhibit such interesting properties. <br />In the literature, various methods are often used and valid indicators of the antioxidant potential of dietary substances. However these assays do not provide evidence that antioxidants have in vivo or ex vivo activity when consumed. To obtain biologically relevant information, the antioxidant activities of the extracts were evaluated on cellular models implicating the measurement of blood haemolysis, the Cellular Antioxidant Activity on endothelial cells and the anti-inflammatory activities on isolated equine stimulated neutrophils and purified myeloperoxidase. <br />These tests generally showed that the blackcurrant leaf extract have the highest antioxidant and <br />anti-inflammatory (inhibition of MPO activity and ROS production on activated neutrophils) capacities correlated to the highest total phenolics content. [less ▲]

Detailed reference viewed: 249 (44 ULg)
Full Text
Peer Reviewed
See detailCultivars, culture conditions and harvest time influence phenolic and ascorbic acid contents and antioxidant capacity of strawberry (Fragaria x ananassa)
Pincemail, Joël ULg; Kevers, Claire ULg; Tabart, Jessica ULg et al

in Journal of Food Science (2012), 77

Strawberries are a good source of micronutrients, especially antioxidant phenolics. More information is needed to better exploit the health-promoting effect of such fruits. Several studies focused on the ... [more ▼]

Strawberries are a good source of micronutrients, especially antioxidant phenolics. More information is needed to better exploit the health-promoting effect of such fruits. Several studies focused on the effects of genotype, cultural practices and seasonal variation on the antioxidant potential of strawberries, but often yielding contradictory results and/or focusing on only one source of variability. In the present study, we showed that total phenolic compounds, ascorbic acid and antioxidant capacity strongly differed between genotypes of strawberry. The precise results revealed the importance of genetic background for the antioxidant capacity and for the content of total phenolics (with up to 3.3-fold variations). Other parameters may also influence the antioxidant capacity in strawberry such as harvest time, culture conditions and environmental factors. Moreover, in this study, the harvesting time (at the same ripening stage) appeared to be very important, more important than genotype. Variations of the antioxidant capacity of up to 4.1-folds were observed following the harvesting time of “Elsanta” cultivar. [less ▲]

Detailed reference viewed: 83 (25 ULg)
Full Text
Peer Reviewed
See detailEvidence of health benefits of of polyphenols enriched foods : from In Vitro studies to clinical trials performed at university - CHU of Liège, Belgium
PINCEMAIL, Joël ULg; Kevers, Claire ULg; Tabart, Jessica ULg et al

in University of Ferrara (Ed.) Second Internaional conference on environmental stressors in biology and medicine (2011, October)

Detailed reference viewed: 43 (11 ULg)
Full Text
See detailMethod for the production of recombinant proteins by green microalgae
Versali, Marie-France ULg; Clerisse, Fabienne ULg; Dommes, Jacques ULg et al

Patent (2011)

The present invention relates to a method for the production of recombinant proteins by algal cells, which are fresh water unicellular green microalgae belonging to the order of Sphaeropleales. The ... [more ▼]

The present invention relates to a method for the production of recombinant proteins by algal cells, which are fresh water unicellular green microalgae belonging to the order of Sphaeropleales. The present invention further provides recombinant algal cells, wherein said algal cells are fresh water unicellular green microalgae belonging to the order of Sphaeropleales, and wherein said algal cells are capable of producing a recombinant protein. The invention is also directed to a method for selecting recombinant algal cells. The invention also relates to the use of recombinant algal cells as described herein for producing recombinant proteins. [less ▲]

Detailed reference viewed: 35 (2 ULg)
Full Text
See detailDo polyamines increase the antioxidant capacity of hyperhydric shoots ?
Franck, Thierry ULg; Tabart, Jessica ULg; Kevers, Claire ULg et al

in 4th international workshop - cost action FA0605 - Book of abstracts - Limassol 17-19 November (2011)

Detailed reference viewed: 38 (5 ULg)
Full Text
Peer Reviewed
See detailAscorbic acid, Phenolic acid, Flavonoid and Carotenoid profiles of selected extracts from Ribes nigrum
Tabart, Jessica ULg; Kevers, Claire ULg; Evers, Danièle et al

in Journal of Agricultural and Food Chemistry (2011), 59

Small fruits such as berries have low energy contents, but high content of vitamins, micronutrients, and dietary fibres and constitute a good source of natural antioxidant compounds that are important ... [more ▼]

Small fruits such as berries have low energy contents, but high content of vitamins, micronutrients, and dietary fibres and constitute a good source of natural antioxidant compounds that are important constituents of the human diet. This study allowed to identify a large number of compounds in an extract of blackcurrant showing high antioxidant activity and to compare their profile in various parts of the plants (leaves, buds and berries). If it was known that berries contained very high levels of natural phenolic compounds, here we showed that leaves and buds could also be considered as a good sources of natural antioxidants. Indeed, they contained high amount of ascorbic acid, phenolic acids, flavonoids and carotenoids. An acetone mixture can extract several classes of phenolic compounds with a good yield of ascorbic acid, flavonols, flavan-3-ols and anthocyanins. For phenolic acids, it extracted fewer compounds than a specific extraction solution. [less ▲]

Detailed reference viewed: 96 (26 ULg)
Full Text
Peer Reviewed
See detailInfluence of cultivar, harvest time, storage conditions, and peeling on the antioxidant capacity and phenolic and ascorbic acid contents of apples and pears."
Kevers, Claire ULg; PINCEMAIL, Joël ULg; Tabart, Jessica ULg et al

in Journal of Agricultural and Food Chemistry (2011), 59

Apple and pear fruits are important sources of secondary plant metabolites and one of the major sources of dietary phenolics consumed all year round. The aim of this work was to identify the main ... [more ▼]

Apple and pear fruits are important sources of secondary plant metabolites and one of the major sources of dietary phenolics consumed all year round. The aim of this work was to identify the main variables influencing phenolic content and antioxidant capacity in apples. Higher phenolic and antioxidant contents were observed in some varieties (such as the Delbar Estival apple and Durondeau pear). Storage conditions were important. Our results also showed that fruits should be consumed rapidly after purchase and with their peel. After one week of domestic storage, the ascorbic acid content was found to decrease by 75%. Peeling led to a more than 25% decrease in total phenolics and ascorbic acid. The harvest time (at normal ripeness) had only a limited impact, but significant year-to-year variations were observed. In conclusion, well-chosen and well-stored apples and pears may contribute to an antioxidant-rich diet if consumed rapidly and with their peel. [less ▲]

Detailed reference viewed: 36 (11 ULg)
Full Text
Peer Reviewed
See detailThe elicitation of a systemic resistance by Pseudomonas putida BTP1 in tomato involves the stimulation of two lipoxygenase isoforms
Mariutto, Martin ULg; Duby, Franceline ULg; Adam, Akram et al

in BMC Plant Biology (2011), 11

Background Some non-pathogenic rhizobacteria called Plant Growth Promoting Rhizobacteria (PGPR) possess the capacity to induce in plant defense mechanisms effective against pathogens. Precedent studies ... [more ▼]

Background Some non-pathogenic rhizobacteria called Plant Growth Promoting Rhizobacteria (PGPR) possess the capacity to induce in plant defense mechanisms effective against pathogens. Precedent studies showed the ability of Pseudomonas putida BTP1 to induce PGPR-mediated resistance, termed ISR (Induced Systemic Resistance), in different plant species. Despite extensive works, molecular defense mechanisms involved in ISR are less well understood that in the case of pathogen induced systemic acquired resistance. Results We analyzed the activities of phenylalanine ammonia-lyase (PAL) and lipoxygenase (LOX), key enzymes of the phenylpropanoid and oxylipin pathways respectively, in tomato treated or not with P. putida BTP1. The bacterial treatment did not stimulate PAL activity and linoleate-consuming LOX activities. Linolenate-consuming LOX activity, on the contrary, was significantly stimulated in P. putida BTP1-inoculated plants before and two days after infection by B. cinerea. This stimulation is due to the increase of transcription level of two isoforms of LOX: TomLoxD and TomLoxF, a newly identified LOX gene. We showed that recombinant TomLOXF preferentially consumes linolenic acid and produces 13-derivative of fatty acids. After challenging with B. cinerea, the increase of transcription of these two LOX genes and higher linolenic acid-consuming LOX activity were associated with a more rapid accumulation of free 13-hydroperoxy-octadecatrienoic and 13-hydroxy-octadecatrienoic acids, two antifungal oxylipins, in bacterized plants. Conclusion In addition to the discovery of a new LOX gene in tomato, this work is the first to show differential induction of LOX isozymes and a more rapid accumulation of 13-hydroperoxy-octadecatrienoic and 13-hydroxy-octadecatrienoic acids in rhizobacteria mediated-induced systemic resistance. [less ▲]

Detailed reference viewed: 78 (31 ULg)
See detailIdentification, characterization and expression profiling of the tomato gene TomLoxF
Mariutto, Martin ULg; Duby, Franceline ULg; Adam, Akram et al

Poster (2010, January 26)

Detailed reference viewed: 29 (10 ULg)
Full Text
Peer Reviewed
See detailTuber formation and growth of Dioscorea cayenensis-D. rotundata complex. Interactions between exogenous and endogenous jasmonic acid and polyamines
Ondo Ovono, Paul ULg; Kevers, Claire ULg; Dommes, Jacques ULg

in Plant Growth Regulation (2010)

Tubers can be initiated and developed in vitro from nodal cuttings of yam (Dioscorea cayenensis - D. rotundata complex). The effect of exogenous jasmonic acid, alone or in combination with putrescine, on ... [more ▼]

Tubers can be initiated and developed in vitro from nodal cuttings of yam (Dioscorea cayenensis - D. rotundata complex). The effect of exogenous jasmonic acid, alone or in combination with putrescine, on these processes was investigated in relationship to endogenous jasmonic acid and polyamine levels. Application of exogenous jasmonic acid at various concentrations positively affected microtuber formation and growth from yam nodal cuttings. In control conditions, three weeks were needed to obtain 100% of tuberisation. Jasmonic acid at low level (0.1 µM) accelerated tuber formation (46% after one week) as did putrescine (10 µM). But endogenous levels of jasmonic acid were not significantly affected by its exogenous presence in the medium. Jasmonic acid also interacted with other growth regulators as polyamines, but the decrease in time necessary to observe tuber formation could not be correlated with endogenous modifications of PUT content. The presence of jasmonic acid (0.1 to 1 µM) as PUT (1 µM) induced also an increase of tuber length and weight. The combination of jasmonic acid (0.1 µM) and putrescine (1 µM) had no positive effect on tuber formation (precocity) but had an additive effect on further growth (length and weight). In the future, these results could help the optimising in vitro conditions for mass production of larger yam microtubers. [less ▲]

Detailed reference viewed: 70 (8 ULg)
Full Text
Peer Reviewed
See detailIn Vitro Preservation of Yam ( Dioscorea cayenensis-D.rotundata complex) for a Better Use of Genetic Resources
Ondo Ovono, Paul ULg; Kevers, Claire ULg; Dommes, Jacques ULg

in Notulae Botanicae Horti Agrobotanici Cluj-Napoca (2010), 38

Among the food crops, yam takes up quantitatively the first place in the gabonese diet. Unfortunately, it can stay available only 6 to 7 months in the year because of difficulties of harvest and post ... [more ▼]

Among the food crops, yam takes up quantitatively the first place in the gabonese diet. Unfortunately, it can stay available only 6 to 7 months in the year because of difficulties of harvest and post- harvest. This problem is little studied in the case of Dioscorea cayenensis-D. rotundata complex. In order to optimize the use of micro tubers for the growing in green house or field, it is important to control the duration of storage before the germination. The present study concerns microtubers obtained by in vitro culture. When microtubers were harvested (after 9 months of culture) and directly transferred on a new medium without hormone, the tubers rapidly sprouted in in vitro conditions. Harvested microtubers were also stored dry in jars in sterile conditions during 2 to 18 weeks before in vitro sprouting. In this case, microtubers stored during 18 weeks sprouted more rapidly than those stored 8 weeks. The size of the tubers used for the storage had great influence on further sprouting. The upper microtubers in 25 mm can be kept to the darkness, under 50% of relative humidity, in 25°C during at least 18 weeks. Sprouting is 100% whatever the substrate of culture. The plant tissue culture technique constitutes a serious alternative for the preservation of plant kinds and for the production of planting material. These techniques allow multiplying in a short time of thousands of copies of new varieties of newly created plants. These in vitro plants can be used on one hand, for the production planting material, and on the other hand for ex vitro storage of breeding grounds with decelerated growth, to struggle against genetic erosion. These results should allow improving in practice the multiplication of yam, while guaranteeing phytosanitary qualities. [less ▲]

Detailed reference viewed: 76 (20 ULg)
Full Text
Peer Reviewed
See detailEvaluation of spectrophotometric methods for antioxidant compound measurement in relation to total antioxidant capacity in beverages.
Tabart, Jessica ULg; Kevers, Claire ULg; Pincemail, Joël ULg et al

in Food Chemistry (2010), 120

The validity of different colorimetric methods used to quantify various families of antioxidant compounds was evaluated with standard compounds. The colorimetric tests for global evaluation of flavonoids ... [more ▼]

The validity of different colorimetric methods used to quantify various families of antioxidant compounds was evaluated with standard compounds. The colorimetric tests for global evaluation of flavonoids, anthocyans, and flavanols were found generally unreliable, as reactions could be different for individual compounds within a family (anthocyanins or flavonols or flavan-3-ols) and not specific to one family. In the flavonoid test, for example, flavonols reacted very well, anthocyanins did not react, and flavanons reacted only slightly. The same methods were applied also to beverages known for their antioxidant content (apple, orange, grape, and vegetable juices, ice tea, and red wine) and the data were compared with the results of HPLC analysis of specific compounds. The values obtained in a colorimetric test were generally higher than the sum of the values obtained for the corresponding individual compounds by HPLC analysis, mainly because other compounds can interfere with the colorimetric tests. For example, in wine, anthocyanin concentrations obtained by colorimetric test were 9068  1407 µ mol /100ml (mean  SEM), higher than the sum of the six main anthocyanidins detected by HPLC, only 41 µmol/100 ml. The relative antioxidant capacity values determined for beverages on the basis of colorimetric tests could exceed by far the values previously measured in radical-scavenging tests (for instance, the antioxidant capacity attributable to anthocyans in wine on the basis of the colorimetric test was 50 times higher than the total antioxidant capacity measured by the ORAC assay). In conclusion, colorimetric tests for flavonoids, anthocyans, and flavanols appeared generally unreliable for estimating their content and thus the antioxidant capacity reliable to these compounds. [less ▲]

Detailed reference viewed: 279 (90 ULg)
Full Text
Peer Reviewed
See detailEffects of storage conditions on sprouting of microtubers of yam (Dioscorea cayenensis-D. rotundata complex).
Ondo Ovono, Paul ULg; Kevers, Claire ULg; Dommes, Jacques ULg

in Comptes Rendus des Séances de l'Académie des Sciences. Série III, Sciences de la Vie (2010)

The control of field tuber dormancy in yam (Dioscorea cayenensis- D.rotundata complex) is poorly understood. Although studies have examined single environmental factors and chemical treatments that might ... [more ▼]

The control of field tuber dormancy in yam (Dioscorea cayenensis- D.rotundata complex) is poorly understood. Although studies have examined single environmental factors and chemical treatments that might prolong tuber dormancy and storage, only a few were focused on further tuber sprouting. The present study concerns microtubers obtained by in vitro culture. When microtubers were harvested (after 9 months of culture) and directly transferred on a new medium without hormone, the tubers rapidly sprouted in in vitro conditions. No dormancy was observed in this case. Harvested microtubers were also stored dry in jars in sterile conditions during 2 to 18 weeks before in vitro sprouting. In this case, microtubers stored during 18 weeks sprouted more rapidly than those stored 8 weeks. A constant “dormancy-like period” (storage duration + sprouting delay) was observed, between 20 and 28 weeks respectively for the more rapid and the slower microtubers. The size of the tubers used for the storage had great influence on further sprouting. The larger they were, the better they sprouted. Light during storage had no effect on the sprouting delay while a temperature of 25 °C permit a quicker sprouting than 18 °C. The medium used to obtain microtubers could also have an effect on sprouting rate. Ex vitro sprouting was not a problem. There was a delay in sprouting in contrast to in vitro conditions but the rate of 100% was kept. This fact was very important for an agronomical application of this technique to the production of “seeds” directly usable in the field or after culture in greenhouse. [less ▲]

Detailed reference viewed: 68 (8 ULg)
Full Text
Peer Reviewed
See detailANTIOXIDANT CAPACITY OF THREE CUBAN SPECIES OF THE GENUS Pluchea Cass. (Asteraceae)
Perera, Wilmer; Tabart, Jessica ULg; Gomez, Abel et al

in Journal of Food Biochemistry (2010), 34

Leaves of three Cuban species of the genus Pluchea: P. carolinensis, P. odorata and P. rosea were extracted with various solvents and analysed. Highest values of phenolic compounds were detected after ... [more ▼]

Leaves of three Cuban species of the genus Pluchea: P. carolinensis, P. odorata and P. rosea were extracted with various solvents and analysed. Highest values of phenolic compounds were detected after ethyl acetate (EtOAc) and n-butyl alcohol (n-BuOH) extractions. Flavonoids were detected after chloroform, EtOAc and n-BuOH extractions of the species Pluchea and three aglycone flavonol forms (quercetin, kaempferol and myricetin) were also quantified after EtOAc and n-BuOH extractions, using HPLC. The total antioxidant capacity (TAC), expressed as Trolox equivalents per gram of leaf dry weight (TE/g dw) was analyzed using 2,2-diphenyl-1-picrylhydrazyl (DPPH•), 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS∙+), and the oxygen radical absorbance capacity (ORAC). The highest values of TAC were detected after EtOAc and n-BuOH extractions of the three species. P. carolinensis was the promising species; being the n-BuOH extraction with the most bioactive compounds : 15.3 mg TE/g dw using DPPH∙ [less ▲]

Detailed reference viewed: 95 (25 ULg)