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See detailExpression des propriétés biologiques des substances humiques de lixiviats sur le développement racinaire de ligneux
Tahiri, Abdelghani ULg

Doctoral thesis (2016)

Humic substances (HS) are a dark-colored heterogeneous organic compounds originated from microbial decomposition and chemical degradation of organic matter. The exact structure and composition of HS ... [more ▼]

Humic substances (HS) are a dark-colored heterogeneous organic compounds originated from microbial decomposition and chemical degradation of organic matter. The exact structure and composition of HS macromolecules are not totally elucidated due to their complexity and their structural heterogeneity. They have long been recognized as plant growth promoting substances, particularly with regard to influencing nutrient uptake, root growth and architecture and by improving soil structure. However, the molecular mechanisms through which HS influence plant physiology are not well understood and must be deepened. The aim of this doctoral thesis is to obtain deeper understanding of the biological activity exerted by HS extracted from landfill leachates in comparaison to a commercial formulation extracted from leonardite on roots growth of woody plants in relation to their chemical characterization and mechanisms of action. Three experimental approach have been carried out. The first one concerns a comparative chemical characterization of total HS and derived fractions, separated in function of their solubility and molecular weight, was performed using elemental analysis, UV-vis, FT-IR and 1H NMR spectroscopy and MALDI-TOF mass spectrometry. Obtained results indicate that HS of both origins were basically similar regarding the presence of their chemical structures but, differ mainly in their relative abundance. The second, concerns the development of an in vitro culture model to study the biological activity of HS on the development of root system of two woody pioneer species. The data obtained showed that the effect of HS depends on plant species, concertation, mode of application and source of HS. If the high molecular weight fraction (HA) was effective at promoting root development, the lower ones (FA and OM) inhibit it in function of the concentration used. Finally, a molecular approach was investigated to study some molecular mechanisms that plant act in response to HS comparing the expression of four genes (ABCB1, ABCB19, GS and ADH) implicated respectively in auxin, nitrogen and carbon metabolisms. Obtained data show that HS and their HA fractions influence root growth and development apparently by influencing different mechanism of regulation associated with polar auxin transport, the incorporation of inorganic nitrogen as glutamate, carbon metabolism and abiotic stress responses. Results presented in this thesis showed that landfill leachates HS especially their HA fraction can be valued as bio-stimulant of plant growth. [less ▲]

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See detailEnhanced biomass production of a novel Acetobacter strain isolated from Moroccan biotopes using response surface methodology approach
Mounir, Majid ULg; Hamas, Khadija; Tamraoui, Khadija et al

Conference (2016, March 21)

The objective of this work was first the isolation of novel acetic acid bacteria strains from natural Moroccan habitats, and then, the evaluation of their ability to produce microbial starters for vinegar ... [more ▼]

The objective of this work was first the isolation of novel acetic acid bacteria strains from natural Moroccan habitats, and then, the evaluation of their ability to produce microbial starters for vinegar production in large-scale. The isolation was made from figs, dates, cactus, and traditional fruit vinegars. Four strains, selected from a total of 63 isolates were confirmed to be belonged to Acetobacter species according to biochemical tests and molecular study based on 16s rDNA sequence analysis. Acetic acid fermentation tests, performed on date and apple fermented juices by the selected Acetobacter strains, showed high capacity of acidification. The most efficient strain, isolated from cactus vinegar, yielded an acidity of about 42.5 g/L on apple juice. A cell growth optimization was carried out on the most efficient strain using the response surface methodology (RSM). The linear, quadratic and interaction effects of four factors; ethanol, acetic acid, glucose and pH were studied by the application of a central composite design. 30 experiments were designed to predict the maximum concentration of cell biomass. The optimal calculated values of ethanol, acetic acid, glucose and pH allowing the prediction of the maximum biomass production (2.2 g/L) were 28.18 g/L, 10.12 g/L, 15.15 g/L and 5.33, respectively. Subsequently, further batch fermentations were carried out in a 6 L lab-bioreactor using the optimased culture medium. The results were in line with the predict values. It was concluded that the studied strain is well suited to be used as parental strain to prepare a starter for vinegar fruit production. [less ▲]

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See detailDéfis et opportunités des outils de découverte : côté professionnel, côté usager
Decoster, Sara ULg; Renaville, François ULg

Conference given outside the academic context (2016)

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See detailLe redoublement en Fédération Wallonie-Bruxelles
Baye, Ariane ULg

Conference given outside the academic context (2016)

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See detailEstimating carbon fluxes in a Posidonia oceanica system: Paradox of the bacterial carbon demand
Velimirov, Branko; Lejeune, Pierre; Kirschner, A. et al

in Estuarine Coastal & Shelf Science (2016), 171

A mass balance ecosystemic approach, based on bacterial carbon demands and primary production data, was used to investigate if the bacterial community (freewater bacterioplankton and benthic bacteria of ... [more ▼]

A mass balance ecosystemic approach, based on bacterial carbon demands and primary production data, was used to investigate if the bacterial community (freewater bacterioplankton and benthic bacteria of the oxygenated sediment layer) could be sustained by the main primary producers (Posidonia oceanica and its epiphytes, adjacent macroalgae and phytoplankton communities; hereafter called the P. oceanica system) of a non-eutrophic Mediterranean bay. Unexpectedly, the findings of this study differed from previous works that used benthic incubation chamber and O2 optode methods. In this study, data were grouped in two categories, corresponding to two time periods, according to the seawater temperature regime (<18 °C or >18 °C): from May to October and from November to April. Between May and October, the produced benthic macrophyte tissues could not provide the carbon required by the bacteria of the oxygenated sediment layer, showing that the balance production of the investigated bay was clearly heterotrophic (i.e. negative) during this time period. In contrast, between November and April, benthic bacteria respiration nearly equated to carbon production. When integrating the open water carbon dynamics above the meadow in the model, a negative carbon balance was still observed between May and October, while a slight carbon excess was noticed between November and April. In the light of these findings, the carbon balance being negative on an annual basis, alternative carbon sources are required for the maintenance of the bacterial carbon production. [less ▲]

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See detail“Rhythm and Repetition in Caryl Phillips’s Dancing in the Dark”
Mascoli, Giulia ULg

Conference (2016, March 20)

My proposal is to deal with Dancing in the Dark (London: Vintage, 2005), a novel by Caryl Phillips, a contemporary British author of Caribbean descent. This narrative is devoted to the Caribbean American ... [more ▼]

My proposal is to deal with Dancing in the Dark (London: Vintage, 2005), a novel by Caryl Phillips, a contemporary British author of Caribbean descent. This narrative is devoted to the Caribbean American entertainer Bert Williams (1874–1922) who was the first black performer in the Ziegfield Follies and it traces his frustrating life as a black performer who had to blackface. Like most of Phillips’s literary production, Dancing in the Dark is shaped by music, both thematically –there are scenes involving musical performances, lyrics interspersed throughout the novel– and formally through the recurrent and creative use of repetitions and meaningful variations in rhythm, and sonic effects. Indeed, various elements of sound are present through poetic language and forms to emphasize elements of rhythm: repetitive devices such as rhymes, meters and alliterations. My contention is that these rhythmic devices partake in the emotional impact of Phillips’s writing; sonic elements emphasize the musical properties of language, strike the reader and prevent them from forgetting the traumatic experience of Bert. Through repetition, they transfer the character’s traumatic experience into the writing and create a sense of sympathy with the reader which privileges immediate empathy. If Bert Williams has been largely forgotten until recently, I believe that Phillips’s rhythmic prose will enable Bert’s story to resonate in the reader’s mind long after closing the book. [less ▲]

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See detailThérapeutiques conservatrices des tendinopathies : quoi de neuf ?
Kaux, Jean-François ULg

in 11ème Congrès d'actualités diagnostiques, éthiques et thérapeutiques de l'arrondissement de Dinant (2016, March 19)

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See detailGoro Gheri as the "perfect secretary"?
Miesse, Hélène ULg

Conference (2016, March 19)

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See detailClinical and molecular classification of glioblastoma patients
Lambert, Jérémy ULg; Kaoma, Tony; Van Dyck, Eric et al

Poster (2016, March 19)

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See detailLes PCSK9 : la mort des statines ?
RADERMECKER, Régis ULg

Conference (2016, March 19)

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See detailThe Islamic coinage of Barqa from the conquest up to the advent of the Fatimids
Bauden, Frédéric ULg

Conference (2016, March 19)

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See detailUnderstanding Usage Behaviour in a Peer-to-Peer Task Community
Deliège, Fanny ULg; Ates, Zelal ULg; Benoit, Sabine et al

Scientific conference (2016, March 18)

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See detailProcedural learning as a measure of functional impairment in a mouse model of ischemic stroke
Linden, Jérôme ULg; Van de Beek, Lise; Plumier, Jean-Christophe ULg et al

in Behavioural Brain Research (2016), 307

Basal ganglia stroke is often associated with functional deficits in patients, including difficulties to learn and execute new motor skills (procedural learning). To measure procedural learning in a ... [more ▼]

Basal ganglia stroke is often associated with functional deficits in patients, including difficulties to learn and execute new motor skills (procedural learning). To measure procedural learning in a murine model of stroke (30min. right MCAO), we submitted C57Bl/6J mice to various sensorimotor tests, then to an operant procedure (Serial Order Learning) specifically assessing the ability to learn a simple motor sequence. Results showed that MCAO affected the performance in some of the sensorimotor tests (accelerated rotating rod and amphetamine rotation test) and the way animals learned a motor sequence. The later finding seems to be caused by difficulties regarding the chunking of operant actions into a coherent motor sequence; the appeal for food rewards and ability to press levers appeared unaffected by MCAO. We conclude that assessment of motor learning in rodent models of stroke might improve the translational value of such models. [less ▲]

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See detail"L'Afrique du Nord, relais d'influence pour la Turquie »
Bayramzadeh, Kamal ULg

Scientific conference (2016, March 18)

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See detailWill Big Data Deliver Its Promised Productivity Growth?
Artige, Lionel ULg

Conference (2016, March 18)

Detailed reference viewed: 30 (1 ULg)