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In this present study, the toxicity of Cleome arabica L. (Capparidaceae) seed oils was tested on L5 larvae of Schistocerca gregaria, Forsk. (Orthoptera-Acrididae). The forced administration of 60 ?L/individual of this vegetable oil leads to the death of all the treated larvae either before or after a few days of exuviation (imaginal moult). Signs of intoxication were observed a few hours after treatment, i.e. movement disorders, diarrhoea, inability to take food and weight loss. Male L5 larvae seem more sensitive than female L5; the mortality rates being around 90.91% and 36.36% respectively after 16 days. The TL50 recorded in treated L5 larvae is around 11 days.

International audience; This study aims to assess for the first time the ability of marine polysaccharides and their derivatives to stimulate natural defenses in olive tree leaves. Alginates, ALSM, and ALCM were isolated from the brown algae Sargassum muticum and Cystoseira myriophylloides, respectively. The OASM and OACM fractions were obtained after radical depolymerization of ALSM and ALCM, respectively. Three sulfated polysaccharides, arabinogalactans (AGB and AGP) and fucoidans (FUCCM) were extracted from the green alga Codium decorticatum and the brown seaweed C. myriophylloides, respectively. The extraction yield of different extracts was in the range of 0.82–32% and the average molecular weight (Mw) varied from 3000 Da to 2173 kDa. The M/G ratios of ALSM and ALCM were 0.87 and 1.12, respectively. FUCCM contained 53% of fucose and 12.83% of sulfates. The AGB and AGP fractions were characterized by the presence of a high degree of sulfation and protein (12–23% (w/w)) and were composed mainly of galactose, glucose, and arabinose. The aqueous saccharide solutions were applied to the leaf discs of the olive tree at 0.5 g/L, 1 g/L, and 2 g/L, for 24 h. These molecules triggered defense responses, by showing a differential capacity to induce the activity of the phenylalanine and tyrosine ammonia-lyase (TAL and PAL), polyphenols, and lignin contents in the leaves of the olive tree. Alginates and their derivatives as well as arabinogalactans exhibited an important induction of TAL activity compared to the PAL. The sulfated polysaccharides were more effective compared to the unsulfated polysaccharides (alginates) which were active at a low concentration. The optimum concentration for most of the studied elicitors was 2 g/L. These results suggest the valorization of these molecules derived from marine biomass as inducers of natural defenses of the olive tree to protect against phytopathogens in the context of sustainable development.

The brown Tunisian seaweed Halopteris scoparia was used as a feedstock for producing renewable bioethanol, biogas, and biodiesel to demonstrate the proof of concept for the North African energy sector. A quantitative and qualitative quantification of H. scoparia composition using different colorimetric methods was completed to highlight its bioconversion potential. These substrate inputs were subjected to anaerobic fermentation by Saccharomyces cerevisiae to produce bioethanol. The materials were also used to generate bio-hydrogen and volatile fatty acids during dark fermentation by a bacterial consortium and using the oleaginous yeast Yarrowia lipolytica. The lipids were extracted and trans-esterified to Fatty Acid Methyl Esters (FAMEs), and their profiles were then analyzed with gas chromatography (GC). A significant ratio of the bioethanol, e.g., 0.35 g ethanol/g DW substrate, was produced without pretreatment, consistent with the theoretical Gay-Lussac yield. The production of the biohydrogen and lipids were up to 1.3 mL H2/g DW substrate and 0.04 g/g DW substrate, respectively, from the raw biomass. These results were higher than those reported for other well-studied seaweeds such as L. japonica. Overall, this work contributes to the current investigations in Tunisia for producing alternative energies from algae and finding new solutions to the current energy situation and environmental challenges in Maghreb.

Alginates extracted from two Moroccan brown seaweeds and their derivatives were investigated for their ability to induce phenolic metabolism in the roots and leaves of tomato seedlings. Sodium alginates (ALSM and ALCM) were extracted from the brown seaweeds Sargassum muticum and Cystoseira myriophylloides, respectively. Low-molecular-weight alginates (OASM and OACM) were obtained after radical hydrolysis of the native alginates. Elicitation was carried out by foliar spraying 20 mL of aqueous solutions (1 g/L) on 45-day-old tomato seedlings. Elicitor capacities were evaluated by monitoring phenylalanine ammonia-lyase (PAL) activity, polyphenols, and lignin production in the roots and leaves after 0, 12, 24, 48, and 72 h of treatment. The molecular weights (Mw) of the different fractions were 202 kDa for ALSM, 76 kDa for ALCM, 19 kDa for OACM, and 3 kDa for OASM. FTIR analysis revealed that the structures of OACM and OASM did not change after oxidative degradation of the native alginates. These molecules showed their differential capacity to induce natural defenses in tomato seedlings by increasing PAL activity and through the accumulation of polyphenol and lignin content in the leaves and roots. The oxidative alginates (OASM and OACM) exhibited an effective induction of the key enzyme of phenolic metabolism (PAL) compared to the alginate polymers (ALSM and ALCM). These results suggest that low-molecular-weight alginates may be good candidates for stimulating the natural defenses of plants.

Sulfated glycoproteins extracted for the first time from the Moroccan green seaweed Codium decorticatum were investigated for their ability to induce a natural defense metabolism in the roots and the upper leaves of tomato seedlings. The crude (AGB) and the purified fractions (AGP) were characterized chemically (Colorimetric assays) and structurally (SEC-MALS, GC-EI/MS, ATR-FTIR). The elicitor aqueous solutions (1 g/L) were applied by foliar spray and syringe infiltration into the internodal middle of 45-day-old tomato seedlings. Phenylalanine ammonia-lyase (PAL) activity, polyphenols, and lignin contents were measured in the roots and the leaves after 0 h, 12, 24, 48, and 72 h of treatment. The AGB and AGP extracts contained 37.67% and 48.38% of the total carbohydrates, respectively, and were mainly composed of galactose, glucose, arabinose, and a minor amount of xylose and rhamnose. They were characterized by an important molecular weight (Mw) > of 2000 × 103 g·mol−1 and a high degree of sulfation and protein (12–23% (w/w)), indicating that the extracted polysaccharides could be an arabinogalactan-rich protein present in the cell wall of the green seaweed C. decorticatum. Both crude and purified fractions exhibited an elicitor effect by inducing the PAL activity, the accumulation of phenolic compounds and lignin contents in the roots and the leaves of tomato seedlings. These responses were systemic in both the methods used (injection and foliar spray) and were mobilized throughout tissues that are not directly treated (roots and/or leaves). Regarding the elicitor activities, AGB and AGP presented globally similar patterns, which revealed the importance of crude extracts in the stimulation of plant immunity. These results suggest the new application of sulfated glycoprotein isolated from green seaweed in agriculture as inducers of natural defenses of plants.

International audience; A water-soluble polysaccharide (PSPC) was extracted from the seeds of Plantago ciliata Desf., a spontaneous Algerian Saharan plant by a hot aqueous extraction then purified by successive ethanolic precipitations. The final extraction yield for PSPC was close to 18.6% (w/v). PSPC was then investigated regarding its global composition, structural features and rheological properties. PSPC is a neutral arabinoxylan, composed of a β-(1,3)/β-(1,4)-D-xylan backbone with side chains of Xylp, and Araf residues attached in O-2 and O-3 positions. The macromolecular characteristics of PSPC in water was determined by SEC/MALLS, with a high molecular weight (Mw) of 700 kDa, a low polydispersity index (PDI) of 1.47 and an intrinsic viscosity [η] close to 157 mL/g. PSPC showed a pseudoplastic behavior in semi-dilute media and the critical overlay concentration (C*) was estimated around 0.32–0.37% (w/v). This current research has supplied original structural information on a new arabinoxylan which could be particularly useful as a novel source of soluble fiber belonging to psyllium.

One of the primary goals in community ecology is to determine the relative importance of processes and mechanisms that control biodiversity. The reduced coverage of vegetation and the severe losses of biodiversity in semiarid matorrals have recently become serious concerns in the Saharan Atlas in southern Algeria. In terms of research, the control of the spatial distribution of vegetation by the topographic factors has not received the attention it merits in Djebel Amour's region. This study combined several multivariate analyses to assess quantitatively the extent and nature of the topographic influence on the distribution of matorral plant species. Thirty plots (20 m × 20 m) were selected according to their physiognomy for the field survey of vegetation and topography in a semiarid mountainous region. The distributions of vegetation differed significantly amongst topographies, indicating different environmental conditions and determine a turnover of important species. Most species colonize downslopes, and only some persist on steep-slopes and summits. The low coverage of vegetation (36.98%) on steep-slopes was due to the serious soil erosion and rockiness 66.5–83.1%. The low average richness in summits (39.67) was due to elevation and negative effect of trees. Elevation, then rockiness and slope were respectively the main topographic factors influencing the distribution of matorral plants. The relationship between topography and distribution could be described by a linear model. Seventeen linear models were built for eleven floristic variables with three topographic factors, elevation, rockiness and slope explained 26–83% of the variance in distribution, also four groups of plant species were listed according to topographic positions. The suitability of plant species to the topographic factors should be considered in the restoration of matorrals in the study area. The results of this study will be useful for selecting the appropriate species and the potential sites for seeding to improving damaged matorral ecosystems in this area. However, additional investigations on soils, water availability and microclimate are required to clarify the mechanism of distribution of plant species in these ecosystems.

The anti-inflammatory and antihyperglycemic effects of polysaccharides extracted from Alhagi maurorum Medik. seeds, spontaneous shrub collected in Southern of Algerian Sahara were investigated. Their water extraction followed by alcoholic precipitation was conducted to obtain two water-soluble polysaccharides extracts (WSPAM1 and WSPAM2). They were characterized using Fourier transform infrared, 1H/13C Nuclear Magnetic Resonance, Gas Chromatography-Mass Spectrometry and Size Exclusion Chromatography coupled with Multi-Angle Light Scattering. The capacity of those fractions to inhibit α-amylase activity and thermally induced Bovine Serum Albumin denaturation were also investigated. WSPAM1 and WSPAM2 were galactomannans with a mannose/galactose ratio of 2.2 and 2.4, respectively. The SEC-MALLS analysis revealed that WSPAM1 had a molecular weight of 1.4 × 106 Da. The investigations highlighted antinflammatory and antihyperglycemic effects in a dose-dependant manner of WSPAM1 and WSPAM2.

This study aimed to examine the anti-termite potential of four Saharan plant extracts, namely, the apple of Sodom or rubber bush, Calotropis procera; pergularia, Pergularia tomentosa; jimsonweed, Datura stramonium, and Egyptian henbane, Hyoscyamus muticus from Bechar (southwest of Algeria) on workers of the harvester termite, Anacanthotermes ochraceus (Isoptera: Hodotermitidae). A direct contact application test was conducted with five fractions from aqueous extracts of each part of plant species (leaves, stems) using hexane, dichloromethane, ethyl acetate, butanol, and exhausted fraction. A repellent test was realized with aqueous extracts (10%) of plant species leaves and stems. According to the direct contact application test, all tested plants fractions showed termiticidal activities with different degrees. Butanolic fractions presented the best effects from leaves of C. procera and P. tomentosa with median lethal time (LT50) = 231.03 and 244.96 min, respectively. In the second test, wood samples were exposed to termite attack for four weeks, and the weight loss percentage was determined. The weight loss ranged from 0.034 to 16.90% at concentrations of 10% of plant extracts. The best repellent effect was obtained from leaves of C. procera (weight loss = 0.034%) and leaves of D. stramonium (weight loss = 1.29%). It was concluded that some Saharan plants are a good source of anti-termite compounds, especially C. procera.

Alhagi maurorum Medik. (Fabaceae) is a spontaneous shrub native to the region extending from Russia to the Mediterranean and used by rural and Saharan Algerian people for its medicinal effects. This study aims to document the medicinal uses of A. maurorum in Illizi (southern Algeria). Ethnobotanical survey was carried out in Illizi between June and September 2018 through face-to-face interviews with 73 residents and traditional practitioners, using prepared questionnaire and specimen indexed of the plant. The data collected were analyzed using χ2 test of independence to study the association between categorical variables. Findings revealed four local names for this plant, the main one being Atjer (57.98%), and the preferential use of leaves (59.42%) and seeds (37.58%). It is consumed mainly by illiterate people (82.60%) over 55 years of age (56.52%) and to treat various ailments such as fever (28.99%) and gastrointestinal disorders (26.08%). The majority of remedies are prepared in the form of a macerate (43.47%). Recorded ethnomedicinal properties of the plant should be subjects of further pharmacological studies to validate their popular use.

Today, an ethnobotanical approach makes sense for identifying new active bioactive chemicals from uses of indigenous plants. Two water-soluble enriched polysaccharide fractions (L-PSPN and S-PSPN) were extracted by hot water extraction from the leaves and seeds of Plantago ciliata Desf. (1798), a Mzab indigenous herb currently used in Algeria by traditional healers. Primary investigation was performed for describing the main structural features of these polysaccharides (pectin- and heteroxylan-like compositions) by using colorimetric assays, FTIR spectroscopy, HPAEC/PAD and GC/MS-EI analyses. Some biological activities were also monitored, such as anticomplement, anti-inflammatory (phagocytic ability, NOX2 and MPO inhibitions) and anti-diabetic (α-amylase and α-glucosidase inhibitions). L-PSPC seems able to moderately modulate innate immune system (IC50 around 100 µg/mL) and contribute to wound-healing processes (IC50 close to 217 vs. 443 µg/mL for sodium heparin). S-PSPC shows some potential as an anti-hyperglycemic (IC50 around 4.7 mg/mL) and anti-inflammatory (IC50 ranging from 111 to 203 µg/mL) agent, as well as other (fiber) psyllium-like polysaccharides extracted from Plantago species.

International audience; Polysaccharides extracted from marine algae have attracted much attention due to their biotechnological applications, including therapeutics, cosmetics, and mainly in agriculture and horticulture as biostimulants, biofertilizers, and stimulators of the natural defenses of plants. This study aimed to evaluate the ability of alginate isolated from Bifurcaria bifurcata from the Moroccan coast and oligoalginates derivatives to stimulate the natural defenses of tomato seedlings. Elicitation was carried out by the internodal injection of bioelicitor solutions. The elicitor capacities were evaluated by monitoring the activity of phenylalanine ammonia-lyase (PAL) as well as polyphenols content in the leaves located above the elicitation site for 5 days. Alginate and oligoalginates treatments triggered plant defense responses, which showed their capacity to significantly induce the PAL activity and phenolic compounds accumulation in the leaves of tomato seedlings. Elicitation by alginates and oligoalginates showed an intensive induction of PAL activity, increasing from 12 h of treatment and remaining at high levels throughout the period of treatment. The amount of polyphenols in the leaves was increased rapidly and strongly from 12 h of elicitation by both saccharide solutions, representing peaks value after 24 h of application. Oligoalginates exhibited an effective elicitor capacity in polyphenols accumulation compared to alginate polymers. The alginate and oligosaccharides derivatives revealed a similar elicitor capacity in PAL activity whereas the accumulation of phenolic compounds showed a differential effect. Polysaccharides extracted from the brown seaweed Bifurcaria bifurcate and oligosaccharides derivatives induced significantly the phenylpropanoid metabolism in tomato seedlings. These results contribute to the valorization of marine biomass as a potential bioresource for plant protection against phytopathogens in the context of eco-sustainable green technolog

The anti-inflammatory and antihyperglycemic effects of polysaccharides extracted from Alhagi maurorum Medik. seeds, spontaneous shrub collected in Southern of Algerian Sahara were investigated. Their water extraction followed by alcoholic precipitation was conducted to obtain two water-soluble polysaccharides extracts (WSPAM1 and WSPAM2). They were characterized using Fourier transform infrared, 1H/13C Nuclear Magnetic Resonance, Gas Chromatography-Mass Spectrometry and Size Exclusion Chromatography coupled with Multi-Angle Light Scattering. The capacity of those fractions to inhibit α-amylase activity and thermally induced Bovine Serum Albumin denaturation were also investigated. WSPAM1 and WSPAM2 were galactomannans with a mannose/galactose ratio of 2.2 and 2.4, respectively. The SEC-MALLS analysis revealed that WSPAM1 had a molecular weight of 1.4 × 106 Da. The investigations highlighted antinflammatory and antihyperglycemic effects in a dose-dependant manner of WSPAM1 and WSPAM2.

International audience; Polysaccharides are highly variable and complex biomolecules whose inventory of structures is still very incomplete, as nature still preserves unexplored biotopes. Plants, macroalgae and microalgae are an integral part of the daily life of human being regardless of culture, time, or knowledge development of a country. Natural medicine is an ancestral knowledge widely distributed throughout the world, handed down for centuries from generation to generation by those commonly referred to as “nganga” healers or shamans. It is also called alternative medicine or traditional medicine, and has been associated for millennia to legends. This review gives an emphasis regarding the ethnobotanic approach associated to the structural variability of poly- and oligosaccharides for designing the new polysaccharide-based drugs and hydrocolloids of tomorrow. The guiding thread is to survey the potential of plants (and some macroalgae) from Africa as a source of polysaccharides with original structures and, secondly, to correlate these structures with biological and/or functional properties in particular to address and advance the sustainable development and economic growth of mankind.

International audience

International audience; A water-soluble polysaccharide fraction (WSPF) was extracted and purified from Astragalus armatus Lam. (Fabaceae), a spontaneous plant found in North Algerian Sahara. The structural features of WSPF were evaluated by colorimetric assays, Fourier transform infrared (FTIR) spectroscopy, high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and gas chromatography coupled to mass spectrometry (GC/MS). WSPF was a galactomannan-rich fraction, with a β-(1,4)-d-manp backbone with α-(1,6)-d-galp branches, and a Man:Gal ratio of 1.13. Besides, the anti-complement activity and the antioxidant potential (DPPH and hydroxyl radicals) of WSPF were evaluated. The results exhibited an anti-complementary activity, with an IC50 value of 0.39 mg/mL of the fraction, better than for heparin (0.58 mg/mL). Moreover, WSPF possessed a notable antioxidant activity on DPPH radical with an IC50 of 330 µg/mL.

International audience; Plantago notata (Plantaginaceae) is a spontaneous plant from Septentrional Algerian Sahara currently used by traditional healers to treat stomach disorders, inflammations or wound healing. A water-soluble polysaccharide, called PSPN (PolySaccharide fraction from Plantago Notata), was extracted and purified from the seeds of this semi-arid plant. The structural features of this mucilage were evaluated by colorimetric assays, Fourier transformed infrared spectroscopy (FT-IR), gas chromatography coupled to mass spectrometry (GC/MS) and 1H/13C Nuclear Magnetic Resonance (NMR) spectroscopy. PSPN is a heteroxylan with a backbone composed of β-(1,3)-d-Xylp and β-(1,4)-d-Xylp highly branched, through (O)-2 and (O)-3 positions of β-(1,4)-d-Xylp by various side chains and terminal monosaccharides such as α-l-Araf-(1,3)-β-d-Xylp, β-d-Xylp-(1,2)-β-d-Xylp, terminal Xylp or terminal Araf. The physico-chemical and rheological analysis of this polysaccharide in dilute and semi diluted regimes showed that PSPN exhibites a molecular weight of 2.3 × 106 g/mol and a pseudoplastic behavior.

We present here a preliminary list of ant fauna of some study sites in thenortheastern Sahara of Algeria using two methodologies, quadrat andpitfall traps (Barber-pots) methods. This work was conducted in wild andagricultural ecosystems in the basin of Ouargla, El-Oued region and Djamaaregion. We record a total of 26 species of 12 genera belonging to threesubfamilies Dolichoderinae, Formicinae, and Myrmicinae. Species of theMyrmicinae and Formicinae were the most abundant with 62.96% and29.63% respectively. The most diverse genus was Monomorium Mayr, 1855(6 species), followed by Messor Forel, 1890 (5). The highest diversity of antswas in Djamaa region (24 species), followed by Ouargla (18) and El-Oued(13). Moreover, this work shows the first record of the species Strumigenysmembranifera Emery, 1869 for the Country. Finally, we observed a variationin the distribution of ant species between study sites, for why, ecologicaldeterminants such as soil need to be studied deeply to explain their influenceon the repartition and richness of the Saharan myrmycofauna of Algeria.

In order to identify the diversity and the characterization of a group of predatory insects which is Mantodea, a special study of this group took place in a dryland habitat which is Ghardaia (Algerian septentrional Sahara). Catches come from several sampling sites corresponding to several habitats (Reg, Wadi and palm grove). Twelve species belonging to five families are inventoried of which 2 species are endemic; Eremiaphila mzabi and Eremiaphila moreti not yet reported in Algeria.The palm grove accommodate the largest species richness (S = 9 species). Mantidae is the richest family (S = 4). The palm grove has a diversity index H' going from 1.42 bit to 1.66 bit and equitability E varies between 0.73 and 0.75. A gradient of vegetation cover reveals stratification in three habitats: palm grove, river and Reg. This heterogeneity of landscapes seems to influence Mantids diversity which is proportional to the vegetation cover, except for the genre Eremiaphila. Mantids identified in these habitats can be classified in three groups, a first group strictly related to palm grove, a second subservient to the natural habitat Reg and a third group with no net belonging, being simultaneously present in both habitats. An inter-habitat variability is emphasized and strata preferences can be distinguished for each species of. The feeding activity of Mantodea is estimated by analyzing their faeces. The diet of mantis confirms their strong entomophagy. For Sphodromantis viridis, the diet is composed of 42.7% of Hymenoptera followed by 19.7% of Aranea (H = 1.68 bit, L = 0.22; E = 0.38). For Amblythespis granulata, analysis of the content of feces reveals 37.7% of Orthoptera (H = 1.58 bits, Simpson’ index = 0.20 and equitability = 0.42). This potentially gives them an impact on populations of prey species.