Antifungal Activity of Resveratrol Derivatives against Candida Species

trans-Resveratrol (1a) is a phytoalexin produced by plants in response to infections by pathogens. Its potential activity against clinically relevant opportunistic fungal pathogens has previously been poorly investigated. Evaluated herein are the candidacidal activities of oligomers (2a, 3–5) of 1a purified from Vitis vinifera grape canes and several analogues (1b–1j) of 1a obtained through semisynthesis using methylation and acetylation. Moreover, trans-ε-viniferin (2a), a dimer of 1a, was also subjected to methylation (2b) and acetylation (2c) under nonselective conditions. Neither the natural oligomers of 1a (2a, 3–5) nor the derivatives of 2a were active against Candida albicans SC5314. However, the dimethoxy resveratrol derivatives 1d and 1e exhibited antifungal activity against C. albicans with minimum inhibitory concentration (MIC) values of 29–37 μg/mL and against 11 other Candida species. Compound 1e inhibited the yeast-to-hyphae morphogenetic transition of C. albicans at 14 μg/mL

Kovásznay modes in stability of self-similar ablation flows of ICF

The history of the linear perturbations in a “laser imprinting” configuration in inertial confinement fusion is described. The time-dependent mean flow is provided by a self-similar solution of gas dynamics equations with nonlinear heat conduction for semi-infinite slabs of perfect gases. The analysis is conducted with the Kovásznay modes, namely the vorticity, acoustic and entropy modes. Exact propagation equations for these three basic modes are derived. Both the similarity solutions and their linear perturbations are numerically computed with an adaptive multidomain Chebyshev method. In particular, the dynamics of the shock wave is detailed. Compressibility effects and possible implications to inertial confinement fusion experiments are emphasized

Linear perturbation amplification in ICF self-similar ablation flows

Exact similarity solutions for inviscid compressible ablative flows in slab symmetry with nonlinear heat conduction are proposed for studying unsteady and compressible effects on the hydrodynamic stability of ablation fronts relevant to inertial confinement fusion (ICF). These similarity solutions and their linear perturbations are computed numerically using a dynamical multidomain Chebyshev pseudo-spectral method. Linear perturbation results obtained for the laser-imprint problem show then that maximum amplification occurs for laser-intensity modulations of vanishing wavenumbers

Spirulina platensis sustainable lipid extracts in alginate-based nanocarriers: An algal approach against biofilms

International audienceCyanobacteria and especially Spirulina platensis are recognized as abundant resources of lipids and polyunsaturated fatty acids (PUFA). The main valorization of these lipids has been the biofuel production but another approach was developed here: the investigation of S. platensis fatty acids as anti-biofilm agent for skin diseases. In fact, chronic wounds represent an important burden for occidental health care systems, and are usually related to the presence of a biofilm, especially of Candida species.In order to develop a biomimetic approach against Candida biofilm formation, free fatty acids (FFA) isolated from microalgae S. platensis were explored. Four solvents, including three bio-sourced ones, and three extraction conditions were screened. Lipid and pigment amounts, combined with FFA profiles were analyzed to select the optimal conditions: 30 min of ultrasonic extraction using dimethylcarbonate or ethylacetate as extraction solvent. A vectorization using a macroalgal-alginate nanocarrier was successfully performed. Vectorized extracts were safe towards keratinocytes and thus compatible with a topical use. Spirulina lipid-enriched extracts showed a high anti-biofilm growth activity at low concentrations (about 80% inhibition after 24 h at 0.2 mg/mL). The combination of extracts in copper-alginate nanocarriers potentiated the anti-biofilm growth activity and exhibited a good anti-biofilm activity (about 50% inhibition after 24 h at 0.1 mg/mL). The combined approach of encapsulated Spirulina lipid extracts represented thus a relevant concept to develop all in one anti-biofilm weapons against Candida and represent a new perspective for algae biomass valorization