GC-MS Determination of Bioactive Compounds of Polygonum glabrum (Wild).

In this study, the bioactive compounds of Polygonum glabrum have been evaluated using GC-MS. The chemical compositions of the whole plant ethanol extract of P. glabrum were investigated using Perkin-Elmer Gas Chromatography-Mass Spectrometry, while the mass spectra of the compounds found in the extract was matched with the National Institute of Standards and Technology (NIST) library. GC-MS analysis of P. glabrum whole plant ethanol extract revealed the existence of the ether compound –Propane 1,1-diethoxy- (64.86%), alkane compound -2-Heptane, 5-ethyl-2,4-dimethyl- (13.51%), sulphur compound –Tiophene-2-Carboxamide, N-(2-furfuryl)- (8.!!%), alcoholic compound -1,14-Tetradecanediol (5.41%), and plasticizer compounds -1,2-Benzenedicarboxylic acid, isodecyloctyl ester (5.41%) and 1,2,3-Benzenetriol (2.79%). The results of this study offer a base of using P. glabrum as herbal alternative for the synthesis of antimicrobial agents

Synergistic effects of squalene and polyunsaturated fatty acid concentrate on lipid peroxidation and antioxidant status in isoprenaline-induced myocardial infarction in rats

We have studied the synergistic effects of squalene and polyunsaturated fatty acids (PUFA concentrate) on isoprenaline-induced infarction in rats with respect to changes in the levels of plasma diagnostic marker enzymes and myocardial antioxidant defense system. Intraperitoneal injection of isoprenaline caused a significant elevation in the levels of diagnostic marker enzymes; alanineaminotranferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine phosphokinase (CPK) in plasma of experimental rats. There was a significant rise in the level of lipidperoxidation with concomitant decline in the level of reduced glutathione (GSH) and in the activities of glutathione-dependent antioxidant enzymes; glutathione peroxidase (GPX) and glutathione-Stransferase (GST), and antiperoxidative enzymes; superoxide dismutase (SOD) and catalase (CAT) in heart tissue. Combined supplementation of squalene and PUFA concentrate significantly prevented the isoprenaline-induced elevations in the levels of diagnostic marker enzymes in plasma of experimental groups of rats. A tendency to counteract the isoprenaline induced lipid peroxidation was also noticed. Their combined administration maintained the level of GSH and the activities of glutathione-dependent antioxidant enzymes and antiperoxidative enzymes at near normalcy. The results of the present study indicated that the combined administration of squalene and PUFA concentrate exerted significantly better cardio-protection against isoprenaline-intoxication as compared to that of per secondsupplementation

Oscillatory surface rheotaxis of swimming E. coli bacteria

Bacterial contamination of biological conducts, catheters or water resources is a major threat to public health and can be amplified by the ability of bacteria to swim upstream. The mechanisms of this rheotaxis, the reorientation with respect to flow gradients, often in complex and confined environments, are still poorly understood. Here, we follow individual E. coli bacteria swimming at surfaces under shear flow with two complementary experimental assays, based on 3D Lagrangian tracking and fluorescent flagellar labelling and we develop a theoretical model for their rheotactic motion. Three transitions are identified with increasing shear rate: Above a first critical shear rate, bacteria shift to swimming upstream. After a second threshold, we report the discovery of an oscillatory rheotaxis. Beyond a third transition, we further observe coexistence of rheotaxis along the positive and negative vorticity directions. A full theoretical analysis explains these regimes and predicts the corresponding critical shear rates. The predicted transitions as well as the oscillation dynamics are in good agreement with experimental observations. Our results shed new light on bacterial transport and reveal new strategies for contamination prevention.Comment: 12 pages, 5 figure

Coupled Self-Organized Hydrodynamics and Stokes models for suspensions of active particles

International audienceWe derive macroscopic dynamics for self-propelled particles in a fluid. The starting point is a coupled Vicsek-Stokes system. The Vicsek model describes self-propelled agents interacting through alignment. It provides a phenomenological description of hydrodynamic interactions between agents at high density. Stokes equations describe a low Reynolds number fluid. These two dynamics are coupled by the interaction between the agents and the fluid. The fluid contributes to rotating the particles through Jeffery's equation. Particle self-propulsion induces a force dipole on the fluid. After coarse-graining we obtain a coupled Self-Organised Hydrodynamics (SOH)-Stokes system. We perform a linear stability analysis for this system which shows that both pullers and pushers have unstable modes. We conclude by providing extensions of the Vicsek-Stokes model including short-distance repulsion, finite particle inertia and finite Reynolds number fluid regime