Higher Institute of Agronomy

Sousse, Tunisia

Higher Institute of Agronomy

Sousse, Tunisia
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Hamissa A.M.B.,Higher Institute of Agronomy | Lodi A.,University of Genoa | Seffen M.,Higher Institute of Agronomy | Finocchio E.,University of Genoa | And 2 more authors.
Chemical Engineering Journal | Year: 2010

The potential of Agave americana fibers as biosorbent was investigated in batch Pb(II) and Cd(II) removal as a function of pH, initial metal concentration and temperature. Metal sorption followed pseudo-second-order kinetics with excellent correlation. The Langmuir model was successfully applied to describe the sorption isotherms. Under optimum conditions (20 °C, pH 5.0, contact time of 30-60 min and 5 g L-1 biomass concentration), the maximum sorption capacity of A. americana fibers was 40.0 mg g-1 for Pb and 12.5 mg g-1 for Cd, respectively. The results obtained at different temperatures allowed estimating the thermodynamic parameters (ΔG°, ΔH° and ΔS°) from the sorption equilibrium constants. The positive ΔH° value obtained for sorption of both metals indicates the endothermic nature of the process. A. americana fibers were also analyzed by IR-FT spectroscopy and scanning electron and metallographic microscopy, with the aim of investigating the interactions of biomass functional groups with cations and evaluating the mechanisms involved in metal sorption. © 2010 Elsevier B.V. All rights reserved.


Latoui M.,Higher Institute of Agronomy | Latoui M.,University of Genoa | Aliakbarian B.,University of Genoa | Casazza A.A.,University of Genoa | And 3 more authors.
Food and Bioproducts Processing | Year: 2012

The primary objective of this study was to valorized Vitex agnus-castus residues in terms of phenolic compounds. The effects of extraction time (30-360 min), solid to liquid ratio (0.1-0.3 g DryBiomass/ml Solvent), type of solvent and different tissue types (leave, roots and seeds) on total polyphenols, o-diphenols, total flavonoids and anthocyanins were evaluated. The highest total polyphenol (31.5 mg CaffeicAcidEquivalent/g DryBiomass) and o-diphenol (12.4 mg CaffeicAcidEquivalent/g DryBiomass) contents were obtained from methanolic extract of leaves after 180 min using a solid/liquid ratio of 0.1 g DryBiomass/ml Solvent, while total flavonoids, reached a maximum value of 19.4 mg CatechinEquivalent/ g DryBiomass after 360 min under the same conditions. Roots of V. agnus-castus were found to be a good source of anthocyanins with the highest yield of 0.62 mg MalvidinEquivalent/g DryBiomass using ethanol as a solvent (180 min and 0.2 g DryBiomass/ml Solvent). The maximum antiradical power (178.5 μl extract/μg DPPH) was exhibited by the methanolic leave extract obtained after 360 min at solid/liquid ratio of 0.3 g DryBiomass/ml Solvent. © 2012 The Institution of Chemical Engineers.


Attig H.,Higher Institute of Agronomy | Dagnino A.,University of Piemonte Orientale | Negri A.,University of Piemonte Orientale | Jebali J.,Higher Institute of Agronomy | And 4 more authors.
Ecotoxicology and Environmental Safety | Year: 2010

In the present study, mussel (Mytilus galloprovincialis) digestive gland oxidative stress biomarkers and detoxification responses to acute exposure to nickel (Ni) were investigated. Mussels were exposed to two sublethal concentrations of Ni (135 γg/L per animal (2.5 γM) and 770 γg/L per animal (13 γM)) for 24, 48, 72, 96. h and 8 days. Following biological responses were measured: (1) glutathione S-transferase (GST) activity as a phase II conjugation enzyme, (2) catalase activity as antioxidant response, (3) malondialdehyde accumulation (MDA) as lipid peroxydation marker and metallothionein as specific response to metals exposure. The cholinergic system was evaluated using the acetylcholinesterase activity (AChE). Moreover, Ni uptakes during the exposure periods were assessed and the uptake rate constant determined. A correlation matrix (CM) between the investigated biomarkers and a principal component analysis (PCA) were achieved for the two tested concentrations. The Ni-uptake constant was higher in animals exposed to the lowest concentration. The CM and the PCA showed a time-dependent effect of the Ni exposure on the investigated biomarkers being more pronounced in animals exposed to the highest Ni concentration. While AChE showed a significant increase after 48. h and a further return to control values in the lowest concentration, it was drastically maintained inhibited in the highest concentration. Our data provided clues about the occurrence of different toxicokinetics and toxicodynamics of two Ni sublethal concentrations in an ecologically relevant organism. © 2010 Elsevier Inc.


Kamel N.,Higher Institute of Agronomy | Attig H.,Higher Institute of Agronomy | Dagnino A.,University of Piemonte Orientale | Boussetta H.,Higher Institute of Agronomy | Banni M.,Higher Institute of Agronomy
Archives of Environmental Contamination and Toxicology | Year: 2012

The present research work was designed to study mussel's (Mytilus galloprovincialis) digestive gland biotransformation and detoxification responses to benzo[a]- pyrene (B[a]P) exposure along with heat stress. Mussels were exposed to a sublethal dose of B[a]P [75 nM (19 μg/L/ animal)] ? temperature gradient (18, 20, 22, 24 and 26 °C) for 7 days. B[a]P hydroxylase (BPH) and glutathione-Stransferase (GST) activities were assessed in digestive gland tissues as phase I and phase II biotransformation parameters. Catalase (CAT) activity and malonedialdehyde (MDA) were measured as potential biomarkers of oxidative stress and lipid peroxidation. The cholinergic system was evaluated using acetylcholinesterase (AChE) activity. DNA damage was assessed using micronuclei (MN) test. BPH and GST activities showed a decreasing trend in B[a]P-exposed animals at 24 and 26 °C. CAT activity showed a bell-shaped response in B[a]P-exposed and in heat-stressed organisms at a maximum temperature of 22 °C. AChE activity was significantly inhibited in response to B[a]P being more pronounced at a temperature of 26 °C. MN in digestive gland cells suggest that B[a]P exposure induced significant DNA alteration with a maximum response in organisms coexposed to B[a]P and a temperature of 26 °C. Biomarker data are further discussed in relation B[a]P accumulation in mussels digestive gland. These data should be carefully considered in view of the biological effects of organic pollutants, particularly in organisms under the challenging effects of extreme temperature fluctuations. © Springer Science+Business Media, LLC 2012.


Mabrouk S.,University of Monastir | Mabrouk S.,Higher Institute of Agronomy | Elaissi A.,University of Monastir | Ben Jannet H.,University of Monastir | And 2 more authors.
Natural Product Research | Year: 2011

The essential oils isolated at the flowering stage in spring, summer and autumn of the aerial and underground parts of Conyza bonariensis L. growing in Tunisia were analysed by GC and GC/MS; 143 constituents were identified, and among them 20 were major. The oils of C. bonariensis gathered in spring were rich in matricaria ester (1.2-67.3%), (Z)-nerolidol (0.3-19.9%) and caryophyllene oxide (0.8-14.3%). In the summer samples, the oils of C. bonariensis were rich in matricaria ester (1.6-76.4%), caryophyllene oxide (1.6-22.6%) and (E) - farnesene (1.1-22.7%). The main constituents in the autumn samples were matricaria ester (trace to 63.5%), geranyl acetone (0.0-25.3%), trans - bergamotene (0.0-24.3%) and limonene (2.7-15.3%). The oils showed significant variation among the seasons. Remarkable differences were found between the constituent percentages of the different studied organs. The C. bonariensis sample from Tunisia was a matricaria ester chemotype and was quite different from the samples of other countries of origin. © 2011 Taylor & Francis.


Jabbes N.,Higher Institute of Agronomy | Arnault I.,University of Tours | Auger J.,University of Tours | Al Mohandes Dridi B.,Higher Institute of Agronomy | Hannachi C.,Higher Institute of Agronomy
Scientia Horticulturae | Year: 2012

This work is aimed at studying diversity of 31 garlic landraces from Tunisia and structuring this diversity. It helped at establishing correlations between content of organo-sulphur compounds and agro-morphological characteristics. For this purpose the quantitative variability of five organo-sulphur compounds, namely: alliin, isoalliin, glutamyl allyl cysteine (GluAlCs), isoglutamyl allyl cysteine (isoGluAlCs) and allicin is studied. The diversity of the accessions for number of leaves per plant, the pseudostem length, dry weight of bulb, weight of one clove, weight of one bulb, bulb diameter, number of cloves in one bulb, the yield and number of days to dormancy release, is assessed. Particular correlations related to the yield and to the organo-sulphur compounds were demonstrated. Genetic diversity was assessed between and within accessions using statistical analyses including coefficients of variation, one way analysis of variance, hierarchical cluster analysis (HCA) and principal component analysis (PCA).Significant agro-morphological traits and organo-sulphur contents variations were found between accessions, except for the number of days for dormancy release (DDR). There is no correlation between total measured organo-sulphur compounds and any of the agro-morphological characteristics. The yield is highly influenced by the following characteristics: weight of the clove, the weight and the diameter of the bulb, the number of leaves per plant and the stem length. Total variance was well described by the first three PCA axes which represent 80.57% of the variance. The PCA and HCA distinguished two major groups of garlic. Clustering does not correspond to the geographical origin but it distinguishes clearly between coloured and light coloured accessions. © 2012 Elsevier B.V.


Elaoud A.,Higher Institute of Agronomy | Chehaibi S.,Higher Institute of Agronomy
Journal of Failure Analysis and Prevention | Year: 2011

Horticulture in Mediterranean areas demand frequent tractor traffic for tillage and for the application of herbicides and pesticides, resulting in soil compaction. Soil compaction is one of the most important factors responsible for soil physical degradation. This compaction by agricultural machines can have adverse effects on crop production and the environment. Different methods have been proposed to estimate soil compaction intensity as a function of vehicle and soil properties such as the soil's water content, bulk density, and resistance to penetration. In this work the authors studied subsoil compaction based on wheel load in the terrain tillage and tillage in a region that was not previously cultivated. A small tractor (engine power 25 kW, type E-TCVS, and weight 1200 kg) was used in the tests. Results showed that the first passage of wheel traffic of the tractor, increases the soil resistance more than the second passage; for example, there is a big difference between the penetration resistance at initial state (2.22 daN/cm 2) and after the first passage (5.72 daN/cm 2), while the variation between the penetration resistance after first passage (5.72 daN/cm 2) and after second passage (6.22 daN/cm 2) is relatively small. This shows that the first passage has the most significant impact on soil compaction. © 2011 ASM International.


Besma B.D.,Higher Institute of Agronomy | Mounir D.,Higher Institute of Agronomy
Journal of Agronomy | Year: 2010

The present research has studied the effects of NaCl and temperature on germination and emergence of okra. Studies were carried out with seeds of a local okra variety (Marsaouia) subjected to 0 and 100 mM NaCl, performed in the dark at 10, 15, 25, 35 and 40°C at germination stage and by 12 h light at emergence stage. The cumulative germination percentage, the cumulative emergence percentage, starch content, the reducing sugars levels, total amylase activity, sodium and potassium accumulation were quantified in germinated seeds at 15°C, 25 and 35°C. Temperature presented a significant effect on salt sensitivity of this species at germination and emergence stages. Germination of okra seeds was completely inhibited at 10 and 40°C. The best germination and emergence temperature was recorded at 25°C. The adverse effect of salt was more pronounced at low and high temperature. During the salt stress treatment, the level of starch reserves was higher at 25°C and lower at 15 and 35°C, an increase in reducing sugars content in cotyledons was observed. The activity of total amylase was most intensive at lower temperature in control seeds and at higher temperature in salt treated seeds. The sodium concentration on germinated seeds increased significantly at 15 and 35°C, but potassium amount did not change regularly within thermal and salt stress interaction. © 2010 Asian Network for Scientific Information.


Dkhil B.B.,Higher Institute of Agronomy | Denden M.,Higher Institute of Agronomy
African Journal of Agricultural Research | Year: 2010

During germination stage, the influence of NaCl on cumulative germination percentage, starch, total soluble sugar and phenol content in okra (Abelmoschus esculentus (L.) Moench, cultivar Marsaouia) seeds and growth seedlings components (cotyledons and embryonic axes) were studied. Seeds were sown in Petri dishes with varying concentrations of saline solutions (0, 20, 40, 60, 80 and 100 mM NaCl) at 25°C. Seed germination decreased significantly with the increase in NaCl concentration, optimal germination percentage occurred in non saline solution reaching 100%. With increasing stress, there was more accumulation of sugar and phenol, starch level decreased markedly especially in cotyledons along with lower amylase activity. Amounts of sodium increased but amounts of potassium did not change significantly with increasing stress. © 2010 Academic Journals.


Dkhil B.B.,Higher Institute of Agronomy | Denden M.,Higher Institute of Agronomy
African Journal of Agricultural Research | Year: 2010

During germination stage, the influence of NaCl on cumulative germination percentage, starch, total soluble sugar and phenol content in okra (Abelmoschus esculentus (L.) Moench, cultivar Marsaouia) seeds and growth seedlings components (cotyledons and embryonic axes) were studied. Seeds were sown in Petri dishes with varying concentrations of saline solutions (0, 20, 40, 60, 80 and 100 mM NaCl) at 25°C. Seed germination decreased significantly with the increase in NaCl concentration, optimal germination percentage occurred in non saline solution reaching 100%. There was more accumulation of sugar and phenol, starch level decreased markedly especially in cotyledons along with lower amylase activity. Amounts of sodium increased but amounts of potassium did not change significantly with increasing stress. © 2010 Academic Journals.

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