Características probióticas de cepas de Lactobacillus plantarum de mantequilla tradicional de leche de camello de regiones áridas (Sáhara) de Argelia

Lactobacillus plantarum strains previously isolated from the traditional butter made from camel milk (shmen) were evaluated for some probiotic criteria. Among 38 strains investigated for bile resistance, 14 were tolerant to 2% oxgall with survival percentages ranging from 69 to 75%. Out of these, only 4 strains (L. plantarum SH5, SH12, SH24 and SH32) were sufficiently resistant to pH 2.0 for 2 to 6 h incubation periods. Only crude extracts of L. plantarum SH12 and L. plantarum SH24 were inhibitory against Lactococcus lactis B8, the strain used as indicator. The antibacterial activity of crude extracts was completely lost after treatment with α-chymotrypsin and proteinase K. L. plantarum SH12 and SH24 strains were susceptible to penicillin G, oxacillin, vancomycin and clindamycin, but resistant to tetracycline and kanamycin. These strains showed rapid acidification activity (0.921 and 1.075 mmol/l of lactic acid, respectively), a good proteolytic activity (5.45 and 3.49 mg/l tyrosine at 72 h, respectively) and high survival percentage after freeze-drying. None of the strains produced polysaccharides or haemolysin in sheep blood.Se evalúan algunas características probióticas de cepas de Lactobacillus plantarum aisladas de la mantequilla tradicional elaborada a partir de leche de camello (shmen). De 38 cepas investigadas para resistencia biliar, 14 fueron tolerantes a un 2% oxgall con porcentajes de supervivencia entre 69 y 75%. De éstas, sólo 4 cepas (L. plantarum SH5, SH12, SH24 and SH32) fueron suficientemente resistentes a pH 2 con periodos de incubación entre 2 y 6 h. Únicamente los extractos crudos de L. plantarum SH12 y L. plantarum SH24 fueron inhibitorios frente a Lactococcus lactis B8, la cepa utilizada como indicador. La actividad antibacteriana de los extractos crudos se perdió completamente después de tratamiento con α-quimotripsina y proteinasa K. Las cepas SH12 y SH24 fueron susceptibles a la penicilina G, oxacilina, vancomicina y clindamicina, pero resistentes a tetraciclina y kanamicina. Dichas cepas mostraron una rápida actividad acidificante (0,921 y 1,075 mmol/l de ácido láctico, respectivamente), una buena actividad proteolítica (5,45 y 3,49 mg/l de tirosina a las 72 h, respectivamente) y un alto porcentaje de supervivencia después de liofilización. Ninguna de las cepas produjo polisacáridos o hemolisina en sangre de oveja

Preliminary characterization of slow growing rhizobial strains isolated from Retama monosperma (L.) Boiss. root nodules from Northwest coast of Algeria

In this paper, we did some preliminary characterization of six slow growing rhizobial strains, isolated from Retama monosperma (L.) Boiss. root nodules sampled from 3 sites along the coast of Oran (CapeFalcon, Bousfer and MersElHadjadj) in Northwestern Algeria. Results of this study showed that all strains had a very slow growth rate in yeast malt (YM) agar medium, forming colonies less than 1 mm in diameter after seven days incubation. Catalase, oxidase and urease were positive, 3-ketolactose was negative. All strains resisted alkaline pH up to 9 and salinity equal to 2% (w/v) NaCl. They grew from 14 to 30°C with optimum growth at 28°C which is related to their place of presence (marine sand dunes Mediterranean climate). The strains used are, on the one hand D-glucose and D-galactose as carbon source and on the other hand L-leucine, L-tyrosine as nitrogen source. The nodulation tests performed pointed out that the total dry weight of the plant could go up to 1.7 g per plant and the maximum number of nodules was equal to 5.6 nodules per plant for the strain RMB1 from Bousfer site. The intrinsic antibiotic resistance level in all strains was tested against nine antibiotics; they revealed a variability of resistance against spectinomycin (10 μg , erythromycin (15 μgml-1, rifampicin (30 μgml-1), streptomycin (500 μgml-1), kanamycin (30 μgml-1), naldixic acid (30 μgml-1), penicillin (6 μgml-1) and tetracycline (30 μgml-1) except for gentamycin (500 μgml-1). The results of electrophoresis on 0.7% agarose gel showed the presence of chromosomal DNA and absence of plasmids.Key words: Retama monosperma (L.) Boiss., Bradyrhizobium, symbiosis, root nodules, nitrogen fixation, endemic legumes, Algeria

Effet du stress hydrique osmotique sur la germination et la croissance in vitro du pistachier vrai (Pistacia vera L.).

Afin de mettre en évidence les potentialités d’adaptation du pistachier fruitier (Pistacia  vera L.) à la sécheresse, un stress hydrique osmotique a été induit en conditions in vitro. L’abaissement du potentiel hydrique du milieu de culture se fait par l’adjonction de polyéthylène glycol (PEG-6000). A cet effet, neuf concentrations croissantes ont été étudiées (0 ; 5 ; 10 ; 15 ; 20 ; 25 ; 30 ; 35 et 40 g l-1). Les résultats essentiels obtenus sont les suivants : la germination des axes embryonnaires n’a pas été affectée par la concentration de PEG-6000. Toutefois, le potentiel hydrique des milieux testés a influencé significativement le taux de survie et l’aspect qualitatif des jeunes plantules germées. En effet, plus la concentration de PEG augmente, plus les taux de mortalité et d’hyperhydrie accentuent. Nos résultats ont montré également un effet très marqué du stress hydrique sur la croissance des vitrosemis de Pistacia vera L. En effet, le taux moyen de réduction de différents paramètres de croissance étudiés par rapport au témoin, est de 51,3% pour la longueur de la partie aérienne, 22,8% pour le nombre de feuilles et 19,9% pour la longueur du système racinaire. En ce qui concerne la production des biomasses, l’analyse statistique a révélé un effet significatif de polyéthylène glycol. Les différentes concentrations étudiées ont entraîné une diminution des biomasses des parties aériennes alors que celles des racines ont été améliorées. Mots clés. Pistacia vera, stress hydrique, polyéthylène glycol, germination in vitro, croissance

Evaluación del sistema reproductivo del endemismo costero Argelino Anacyclus linearilobus (Anthemideae, Asteraceae)

The breeding system of Anacyclus linearilobus, an annual and endemic species restricted to dune ecosystems of the Algerian coast were assessed through the effect of self-fertilization and intra- and inter-population artificial crosses on the probability of producing viable seeds in 20 individuals from two populations in a common garden. The breeding system was determined for each individual by the self-incompatibility index (ISI). These results were compared with those published for other species of the genus, A. clavatus, A. homogamos and A. valentinus. Results of experimental crosses showed that there was high variation in the female reproductive success between individuals of A. linearilobus, like that found in its sister species, A. valentinus. Unlike the other species in the genus that are self-incompatible, A. linearilobus showed a mixed mating system, with a majority of self-incompatible individuals, others partially self-incompatible and some self-compatible. We argue that this strategy may be related to reproductive assurance in this endemic, annual species whose effective population size has been reduced probably due to individual mating incompatibilities.Se evaluó el sistema de cruzamiento de Anacyclus linearilobus, una especie anual y endémica, de reducida distribución en ecosistemas dunares de la costa argelina, mediante la probabilidad de producir semillas en 20 individuos de dos poblaciones, cultivadas en jardín. El sistema de reproducción se determinó para cada individuo por el índice de autoincompatibilidad (ISI). Estos resultados se compararon con los publicados para otras especies del género, A. clavatus, A. homogamos y A. valentinus. Los resultados de los cruces experimentales mostraron que hubo una gran variación en el éxito reproductivo femenino entre individuos de A. linearilobus, como la encontrada en su especie hermana, A. valentinus. A diferencia de las otras especies del género que son autoincompatibles, A. linearilobus mostró un sistema de cruzamiento mixto, con una mayoría de individuos autoincompatibles, otros parcialmente autoincompatibles y algunos autocompatibles. Argumentamos que esta estrategia puede estar relacionada con el aseguramiento reproductivo en esta especie anual endémica cuyo tamaño efectivo de población se ha reducido probablemente debido a incompatibilidad entre individuos emparentados

Investigation of Argania spinosa L. (Skeels) polyphenols growing in arid and semi-arid conditions

Argania spinosa L. Skeels, belonging to the Argania genus of the Sapotaceae family, is a species native to Morocco and Algeria. Due to its perfect adaptation to soil and climate, this tree plays an important ecological role in a constantly threatened encroached desert region. To understand the biological role of polyphenols in making the argan tree adapts to its natural habitat, we conducted a comparative study in two of the tree development stations: Tindouf located in South-western Algeria and Stidia located in Northwest Algeria. High performance liquid chromatography (HPLC) and Gas chromatography-mass spectrometry (GC-MS) used for the analysis of flavonoids led to the identification of six flavonols (two types of myricetin, rutin, hyperoside, quercetin, kaempferol) in the leaves of Tindouf argan tree, and two molecules (myricetin and quercetin) in the leaves of Stidia argan tree. Other molecules presented are few. The determination of flavonoids by spectrophotometry revealed the richness of Tindouf argan in these compounds (20%) compared to that of Stidia argan tree (8.7%). Histolocalisation of the flavonoids, tannins and anthraquinone in the leaves and stems of the tree was done using fluorescence microscope to understand the role of these molecules in the protection of this tree in its environment.Key words: Aragania spinosa L. (Skeels), histolocalisation, polyphenols, high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS)

Selección de cepas de Lactobacillus plantarum para su uso como cultivos iniciadores en la fermentación de aceitunas de Argelia

The aim of this research was to evaluate some technological traits of L. plantarum strains previously isolated from fermented olives. For this purpose, 11 strains were tested for their in vitro antibiotic susceptibility, resistance to low pH values, acidifying activity, proteolytic activity, haemolytic activity, lactic acid and exopolysaccharide production and resistance to freeze-drying .Collectively, the strains were susceptible to most of the antibiotics tested and showed survival at pH 2. Most strains showed high (1.035 ± 0.29 to 0.912 ± 0.21 mmol/l ± sd of lactic acid) or medium (0.556 ± 0.29 to 0.692 ± 0.18 mmol/l±sd) acidification activity with good proteolytic activity (1.49 ± 0.25 to 5.25 ± 0.11 mg L–1 tyrosine). None of the strains produced exopolysaccharides or haemolysis in sheep’s blood.El objetivo de esta investigación fue evaluar algunos aspectos tecnológicos de cepas de L. plantarum previamente aisladas de aceitunas fermentadas. Para este propósito, 11 cepas fueron usadas para estudiar su susceptibilidad a antibióticos in vitro, resistencia a valores de pH bajos, actividad acidificante, proteolítica, y hemolítica, producción de ácido láctico y exopolisacáridos, y resistencia a la liofilización. En general, las cepas fueron susceptibles a la mayoría de los antibióticos ensayados y mostraron supervivencia a pH 2. La mayoría de las cepas mostraron una actividad de acidificación alta (1.035 ± 0.29 a 0.912 ± 0.21 mmol/l de ácido láctico) o media (0.556 ± 0.29 a 0.692 ± 0.18 mmol/l) con una buena actividad proteolítica (1.49 ± 0.25 a 5.25 ± 0.11 mg L–1 tirosina). Ninguna de las cepas produjo exopolisacáridos o hemolisis en sangre de oveja

Assessment of the breeding system in the Algerian narrow coastal endemism Anacyclus linearilobus (Anthemideae, Asteraceae)

The breeding system of Anacyclus linearilobus, an annual and endemic species restricted to dune ecosystems of the Algerian coast were assessed through the effect of self-fertilization and intra- and inter-population artificial crosses on the probability of producing viable seeds in 20 individuals from two populations in a common garden. The breeding system was determined for each individual by the self-incompatibility index (ISI). These results were compared with those published for other species of the genus, A. clavatus, A. homogamos and A. valentinus. Results of experimental crosses showed that there was high variation in the female reproductive success between individuals of A. linearilobus, like that found in its sister species, A. valentinus. Unlike the other species in the genus that are self-incompatible, A. linearilobus showed a mixed mating system, with a majority of self-incompatible individuals, others partially self-incompatible and some self-compatible. We argue that this strategy may be related to reproductive assurance in this endemic, annual species whose effective population size has been reduced probably due to individual mating incompatibilities

Tamaño del genoma, número cromosomático y organización del rDNA en poblaciones argelinas de Artemisia herba-alba (Asteraceae), una planta básica para la alimentación animal en el contexto de la erosión por sobrepastoreo

Artemisia herba-alba is a largely-distributed and often landscape-dominating taxon in arid areas of the Mediterranean and Irano-Turanian regions. In Algeria, in 2010 its communities covered 10% of the steppe territory, but its populations have been subjected to overgrazing. A karyological study based on 22 populations together with a cytogenetic characterisation of this species has been performed for the first time in Algerian materials, through genome size and chromosome number determination. Fluorescence in situ hybridisation (FISH) was also used to assess the rDNA loci number and distribution in the two ploidy levels detected. The studied accessions are diploid (2n = 2x = 18 chromosomes, 6 populations) or tetraploid (2n = 4x = 36 chromosomes, 15 populations). One population, occupying a more or less central geographic position among the studied area, presented both cytotypes. Genome size reflects well the two ploidy levels, with no evidence of downsizing with polyploidy. The karyotypes are rather symmetric (2A Stebbins’ class). FISH analyses detected four signals (2 loci) in diploid and eight signals (4 loci) in tetraploid cytotypes for both ribosomal DNA genes, which present an L-type (linked) organisation, i.e. with loci from both rDNA genes colocalised. The presence of two ploidy levels suggest a genomic dynamism and even a possible differentiation underlying the morphological uniformity and despite the dramatic decrease experienced by this plant in Algeria in terms of surface coverage.Artemisia herba-alba es un taxon ampliamente distribuido y dominante en el paisaje en áreas áridas de las regiones mediterránea e irano-turania. En Argelia, sus comunidades cubrían en 2010 el 10% de su territorio de estepa, pero sus poblaciones se encuentran sometidas a sobrepastoreo. Se ha llevado a cabo un estudio cariológico basado en 22 poblaciones, se han caracterizado citogenéticamente por primera vez poblaciones argelinas de esta especie y se ha estimado el tamaño del genoma y el número cromosomático, además de la determinación por hibridación in situ fluorescente (FISH) del número y la distribución de los loci del ADN ribosómico en los dos niveles de ploidía. Las accesiones estudiadas son diploides (2n = 2x = 18, 6 poblaciones) o tetraploides (2n = 4x = 36, 15 poblaciones), y una, que ocupa una posición más o menos céntrica entre las consideradas, presenta ambos niveles de ploidía. El tamaño del genoma refleja los dos niveles de ploidía y no se observan indicios de disminución con la poliploidía. Los cariotipos son simétricos (clase 2A de Stebbins). Los análisis de FISH detectan cuatro señales (2 loci) en los citotipos diploides y ocho señales (4 loci) en los tetraploides para ambos genes del ADN ribosómico, que presenta una organización del tipo L (ligada), es decir, con los loci de los dos genes del ADNr colocalizados. La presencia de dos niveles de ploidía sugiere un dinamismo genético e incluso una posible diferenciación más allá de la uniformidad morfológica, con independencia del retroceso experimentado por esta planta en Argelia

Determination of anticholinesterase and antioxidant activities of methanol and water extracts of leaves and fruits of Chamaerops humilis L.

The present study was carried out to investigate the antioxidant activity of the water and methanol extracts of leaves and fruits extracts of Chamaerops humilis L. by using ABTS cation radicals and cupric reducing antioxidant capacity (CUPRAC). Anticholinesterase effect of the extracts was tested against both AChE and BChE using a microplate-reader assay based on the Ellman method. The methanol extracts of C. humilis leaves contained relatively higher content of flavonoids and total phenolics than those of fruits. All the extracts were found to have different levels of antioxidant activity in the systems tested. The leave extract showed the highest value of antioxidant activity, based on ABTS radical-scavenging activity, while the fruit water extract showed the highest value (0.53±0.50 µg/mL) of cupric reducing antioxidant activity.  Our data indicates that both methanol and water fruit extract were active for BChE inhibition (31.65 ± 0.37 and 30.19 ± 0.56%) respectively, whereas, all leave extracts did not show any activity against BChE. The present study demonstrated that the methanol and water extracts fractions of C. humilis have different responses with different antioxidant methods. Our results suggest that the C. humilis could be used as a source of antioxidant agents and may be beneficial in the AD treatment