Évaluation de l’activité biologique des feuilles de l’olivier sauvage et cultivé

L’olivier est très répondu en Algérie et largement utilisé par les populations locales. Les propriétés médicinales de l’olivier sont surtout attribuées aux feuilles. Dans le cadre de la valorisation des ressources naturelles, nous avons essayé dans cette étude de contribuer à la connaissance de certains effets biologiques des feuilles de l’olivier sauvage (Olea europea subsp europae var. sylvestris) et de l’olivier cultivé (Olea europea subsp europea var. sativa) récoltés dans la wilaya de Tizi-Ouzou. L’utilisation de ces dernières en phytothérapie par la population locale se fait à l’état naturel (infusion ou décoction). Les feuilles sont utilisées pour leur effet hypoglycémiant et hypotenseur à des doses journalières de 40 à 50g. L’extraction des polyphénols totaux a été faite par macération au méthanol. Le rendement était de 38,74% pour l’olivier sauvage et 35, 72% pour le cultivé. L’évaluation de l’activité antioxydante des polyphénols totaux par la méthode de DPPH révèle une valeur de CI50 de 0.24mg/mL. Ceci classe les polyphénols de l’olivier comme antioxydant puissant. L’administration d’un volume de 2mL de tisane, préparée à partir de 50 g de feuille, à des rats rendus diabétiques par une dose de 150mg/kg d’alloxane a provoqué une diminution très hautement significative (P ˂ 0.0005) de la glycémie et des variations non significative (p ˃ 0.05) de cholestérolémie et de triglycérides.Mots-clés : Olea europea, polyphénols, alloxane, antioxydant, antihyperglycémiant.Evaluation of the biological activity of the leaves of wild and cultivated oliveThe olive tree is omnipresent in Algeria and widely used by local people. The medicinal properties of the olive tree are mostly attributed to the leaves. As part of the development of natural resources, we tried in this study contribute to the knowledge of some biological effects of leaves of wild olive (Olea europaea subsp europae var . Sylvestris) and cultivated (Olea europea subsp europea var. sativa) collected in the wilaya of Tizi Ouzou. The use of herbal medicine in the past by the local population is in its natural state (infusion or decoction). The leaves are used for their hypoglycemic and hypotensive effect at daily doses of 40 to 50g. The extraction of total polyphenols was made by maceration with methanol. The yield was 38.74% for the wild olive and 35, 72% for cultivated. The evaluation of the antioxidant activity of total polyphenols by the DPPH method reveals an IC50 value of 0.24mg/mL. This class of olive polyphenols as a potent antioxidant. The administration of a volume of 2 ml of tea, prepared from 50 g of leaf in diabetic rats with a dose of 150mg/kg of alloxan has caused a very highly significant (P ˂ 0.0005) of the glucose and insignificant changes (p ˃ 0.05) cholesterol and triglycerides.Keywords : Olea europea, polyphenols, alloxan, antioxidant, antihyperglycemic

A generalized quantum nonlinear oscillator

We examine various generalizations, e.g. exactly solvable, quasi-exactly solvable and non-Hermitian variants, of a quantum nonlinear oscillator. For all these cases, the same mass function has been used and it has also been shown that the new exactly solvable potentials possess shape invariance symmetry. The solutions are obtained in terms of classical orthogonal polynomials

Comparative gene expression analysis of susceptible and resistant near-isogenic lines in common wheat infected by Puccinia triticina

Gene expression after leaf rust infection was compared in near-isogenic wheat lines differing in the Lr10 leaf rust resistance gene. RNA from susceptible and resistant plants was used for cDNA library construction. In total, 55 008 ESTs were sequenced from the two libraries, then combined and assembled into 14 268 unigenes for further analysis. Of these ESTs, 89% encoded proteins similar to (E value of < or =10(-5)) characterized or annotated proteins from the NCBI non-redundant database representing diverse molecular functions, cellular localization and biological processes based on gene ontology classification. Further, the unigenes were classified into susceptible and resistant classes based on the EST members assembled from the respective libraries. Several genes from the resistant sample (14-3-3 protein, wali5 protein, actin-depolymerization factor and ADP-ribosylation factor) and the susceptible sample (brown plant hopper resistance protein, caffeic acid O-methyltransferase, pathogenesis-related protein and senescence-associated protein) were selected and their differential expression in the resistant and susceptible samples collected at different time points after leaf rust infection was confirmed by RT-PCR analysis. The molecular pathogenicity of leaf rust in wheat was studied and the EST data generated made a foundation for future studies

Habitat de la Tourterelle des bois (Streptopelia turtur) dans la vallée d’Isser, Algérie

Depending on the resulting habitat mosaic, that is created, habitat loss can reduce the abundance and diversity of birds. Turtle Dove (Streptopelia turtur) is particularly likely to suffer from such pressure, yet few studies have been performed to evaluate its conservation status in Algeria. The information on breeding habitat requirements for turtle dove is important for managing remnant woodlots and shrub land used by this species. To address this issue we surveyed the species in a suburban area of 1087 ha situated in the Isser Valley in Boumerdes (northern Algeria). In order to determine past and predicted future trends in habitat availability we compared landscape types in 2006 with those present in the 1960s and found that nine of the 11 habitats surveyed were occupied by turtle doves in 2006-07. The mean density of turtle doves across our study area was 0.79 pairs/ha during 2006 and 2007. Hatching success was 36.5% and post-fledging nesting success reached 67.7%. A comparison of habitat diversity between the 1960s and 2006 showed an increase of forest- related habitats, which tends to favour turtle doves’ persistence, and could possibly reduce the effect of the landscape homogenization related to anthropogenic land use practices. Being classified as a habitat specialist, the Turtle Dove is likely to decline in the Isser Valley under continuing habitat changesSelon la mosaïque paysagère qui en résulte la perte d’habitat peut réduire l’abondance et la diversité des oiseaux. La Tourterelle des bois (Streptopelia turtur) est particulièrement susceptible de pâtir d’une telle pression ; toutefois, peu d’études ont cherché à évaluer l’état de sa conservation en Algérie. Des informations sur les besoins de cette tourterelle en matière d’habitats de reproduction sont importantes pour la gestion des boisements qu’elle utilise. Pour aborder cette question nous avons recensé l’espèce dans une zone suburbaine de 1087 ha dans la vallée d’Isser à Boumerdes (nord de l’Algérie). Afin de déterminer les disponibilités d’habitats passées et futures, nous avons comparé les types de paysages de 2006 à ceux des années 1960 et avons trouvé que neuf des onze habitats recensés étaient occupés par la Tourterelle des bois en 2006-07. La densité moyenne dans notre zone d’étude a été de 0,79 couples/ha en 2006 et 2007. Le succès à l’éclosion a été de 36,5 % et celui à l’envol a atteint 67,7 %. La comparaison de la diversité des habitats entre 1960 et 2006 a montré une augmentation des habitats forestiers, ce qui est en faveur de la persistance de la Tourterelle des bois et pourrait peut-être réduire les effets d’homogénéisation paysagère dus aux usages des terres par les populations humaines. Classée spécialiste quant à son choix d’habitat, le Tourterelle des bois déclinera vraisemblablement si les habitats continuent à se modifie

Substrate-Inspired Fragment Merging and Growing Affords Efficacious LasB Inhibitors

Extracellular virulence factors have emerged as attractive targets in the current antimicrobial resistance crisis. The Gram-negative pathogen Pseudomonas aeruginosa secretes the virulence factor elastase B (LasB), which plays an important role in the infection process. Here, we report a submicromolar, non-peptidic, fragment-like inhibitor of LasB discovered by careful visual inspection of structural data. Inspired by the natural LasB substrate, the original fragment was successfully merged and grown. The optimized inhibitor is accessible via simple chemistry and retained selectivity with a substantial improvement in activity, which can be rationalized by the crystal structure of LasB in complex with the inhibitor. We also demonstrate an improved in vivo efficacy of the optimized hit in Galleria mellonella larvae, highlighting the significance of this class of compounds as promising drug candidates

The seven lives of Airbnb. The role of accommodation types

This paper investigates how COVID-19 is impacting different accommodation types, and whether travellers' choices regarding accommodation type are affected by the need for physical distance. Study 1 shows that travellers are very reluctant to book shared flats on Airbnb during the pandemic. However, full flats – controlling for price levels - are preferred to hotel rooms. Study 2 clarifies the process behind the increased choice for full flats, i.e., the need for physical distance. In Study 3, we actively manipulate physical distance and show that assuring physical distance will reduce the concerns towards hotel and shared flat options. Apart from enlightening the psychological process behind accommodation choice, the study offers operators actionable suggestions on how to maximise bookings despite the pandemic. © 202

N-Aryl mercaptoacetamides as potential multi-target inhibitors of metallo-β-lactamases (MBLs) and the virulence factor LasB from Pseudomonas aeruginosa

Increasing antimicrobial resistance is evolving to be one of the major threats to public health. To reduce the selection pressure and thus to avoid a fast development of resistance, novel approaches aim to target bacterial virulence instead of growth. Another strategy is to restore the activity of antibiotics already in clinical use. This can be achieved by the inhibition of resistance factors such as metallo-β-lactamases (MBLs). Since MBLs can cleave almost all β-lactam antibiotics, including the “last resort” carbapenems, their inhibition is of utmost importance. Here, we report on the synthesis and in vitro evaluation of N-aryl mercaptoacetamides as inhibitors of both clinically relevant MBLs and the virulence factor LasB from Pseudomonas aeruginosa. All tested N-aryl mercaptoacetamides showed low micromolar to submicromolar activities on the tested enzymes IMP-7, NDM-1 and VIM-1. The two most promising compounds were further examined in NDM-1 expressing Klebsiella pneumoniae isolates, where they restored the full activity of imipenem. Together with their LasB-inhibitory activity in the micromolar range, this class of compounds can now serve as a starting point for a multi-target inhibitor approach against both bacterial resistance and virulence, which is unprecedented in antibacterial drug discovery