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International audience; Pistacia lentiscus L. is known in some Tunisian forest area by its fixed oil used in traditional medicine as an antiseptic product. This investigation is the first to study the antimicrobial activity of P.lentiscus edible oil and its phenolic extract. Oil was extracted from fruits harvested from six provenances located in Tunisia. The antimicrobial activity was tested using disc diffusion assay and the broth dilution method. Kbouch and Sidi Zid oils were most efficient (p

International audience; Global environmental concern, regarding the use of petroleum-based packaging materials, is encouraging researchers and industries in the search for packaging materials from natural biopolymers. Bioactive packaging is gaining more and more interest not only due to its environment friendly nature but also due to its potential to improve food quality and safety during packaging. Some of the shortcomings of biopolymers, such as weak mechanical and barrier properties can be significantly enhanced by the use of nanomaterials such as nanocellulose (NC). The use of NC can extend the food shelf life and can also improve the food quality as they can serve as carriers of some active substances, such as antioxidants and antimicrobials. The NC fiber-based composites have great potential in the preparation of cheap, lightweight, and very strong nanocomposites for food packaging. This review highlights the potential use and application of NC fiber-based nanocomposites and also the incorporation of bioactive agents in food packaging.

International audience; The study was carried out to evaluate the effects of gamma-irradiation alone or in combination with oregano essential oil on murein composition of Staphylococcus aureus and on the intracellular and extracellular concentration of ATP. The bacterial strain was treated with 3 irradiation doses: 1.2 kGy to induce cell damage, 2.9 kGy to obtain a viable but nonculturable state, and 3.5 kGy to cause cell death. Oregano essential oil was used at 0.010% and 0.013% (w/v), which is the minimum inhibitory concentration (MIC). All treatments had a significant effect (P < or = 0.05) on the murein composition, although some muropeptides did not seem to be affected by the treatment. Each treatment influenced differently the relative percentage and number of muropeptides. There was a significant (P < or = 0.05) correlation between the reduction of intracellular ATP and increase in extracellular ATP following treatment of the cells with oregano oil. The reduction of intracellular ATP was even more important when essential oil was combined with irradiation. Also, irradiation alone of S. aureus induced a significant decrease (P < or = 0.05) of the internal ATP and a significant increase (P < or = 0.05) of the external ATP. However, no significant difference (P > 0.05) was observed in ATP concentrations between different radiation doses. Transmission electron microscopic observation revealed that oregano oil and irradiation have an effect on cell wall structure.

International audience; The antibiofilm activity of 10 terpenes was tested in vitro against three Candida species by 24-h treatment of biofilms aged 1-5 days. Treatment of 24-h-old Candida albicans biofilms with carvacrol, geraniol or thymol (0.06%) resulted in >80% inhibition. Carvacrol (0.03%) inhibition was > or =75% independent of the age of the C. albicans biofilm. Carvacrol (0.125%) inhibition was >75% against Candida glabrata and Candida parapsilosis biofilms. Geraniol (> or =0.125%) and thymol (0.06% or 0.125%) inhibition was >75% against C. parapsilosis biofilms whatever their age. This study demonstrates the antibiofilm activity of terpenes and points out the exceptional efficiency of carvacrol, geraniol and thymol, which could represent candidates in the treatment of candidiasis associated with medical devices.

International audience; The essential oil of wild Daucus carota L. obtained from aerial parts at the end of the flowering stage (DCEO) was reported as antimicrobial against the human enteropathogen Campylobacter jejuni. The aim of the present study was to extend this analysis to other Campylobacter species and to identify the active compounds of the essential oil, subjected to GC, GC-MS, and (13)C NMR analysis. A minimum inhibitory concentration assay was used to quantify the antimicrobial activity of DCEO and the major components, isolated on column chromatography. Growth of all the C. jejuni, Campylobacter coli, and Campylobacter lari strains tested, including one multidrug resistant C. jejuni, was inhibited to the same extent by DCEO. Molecules that were responsible for the antibacterial activity were identified as (E)-methylisoeugenol and elemicin. Moreover, the use of structural analogues of these compounds allowed us to identify important features that may account for the activity.

In the mammalian forebrain, most neurons originate from proliferating cells in the ventricular zone lining the lateral ventricles, including a discrete area of the subventricular zone (SVZ). In this region, neurogenesis continues into adulthood. Most of the cells generated in the SVZ are neuronal precursors with progeny that migrate rostrally along a pathway known as the rostral migratory stream before they reach the main olfactory bulb (MOB) where they differentiate into local interneurons. The olfactory system thus provides an attractive model to investigate neuronal production and survival, processes involving interplay between genetic and epigenetic influences. The present study was conducted to investigate whether exposure to an odor-enriched environment affects neurogenesis and learning in adult mice. Animals housed in either a standard or an odor-enriched environment for 40 d were injected intraperitoneally with bromodeoxyuridine (BrdU) to detect proliferation among progenitor cells and to follow their survival in the MOB. The number of BrdU-labeled neurons was not altered 4 hr after a single BrdU injection. In contrast, the number of surviving progenitors 3 weeks after BrdU injection was markedly increased in animals housed in an enriched environment. This effect was specific because enriched odor exposure did not influence hippocampal neurogenesis. Finally, we showed that adult mice housed in odor-enriched cages display improved olfactory memory without a change in spatial learning performance. By maintaining a constitutive turnover of granule cells subjected to modulation by environmental cues, ongoing bulbar neurogenesis could be associated with improved olfactory memory.

International audience; Flavonoids are ubiquitous polyphenolic compounds, found in vascular plants, which are endowed with a large variety of biological effects. Some of these effects have been assumed to result from interactions with the cell plasma membrane. In order to investigate the nature of these interactions a fluorescence study was performed with two flavonoids, currently used in one of the laboratories: apigenin and its homologous dimer amentoflavone. After preliminary assays with DPH in several types of phospholipid liposomes, the effects of these flavonoids on the membrane of mouse L929 fibroblasts were compared, using the non-permeant probe TMA-DPH. Amentoflavone, unlike apigenin, induced a static quenching effect, which denoted an important, but reversible, association of the molecule with the plasma membrane. In addition, amentoflavone treatment induced a dose-dependent increase in TMA-DPH fluorescence anisotropy, which could be interpreted as an increase in membrane lipidic order. For apigenin, the effect was much less important. Moreover, exploiting the capacity of TMA-DPH to label endocytic compartments, it was shown that, after association with the membrane, amentoflavone is not internalized into the cell. Possible correlations of these membrane effects with other biological properties are discussed.