Use of grapevine cell cultures for the production of phytostilbenes of cosmetic interest

AbstractPlant cell cultures constitute pesticide-free sources for obtaining plant secondary metabolites or plant extracts. Additionally, they do not contain any fungal contaminants, mycotoxins or heavy metals providing to the consumer potential health benefits and justifying the development of this technology at an industrial scale. Significant production levels of these secondary metabolites can be obtained through the use of elicitors, which activate plant defense mechanisms. Resveratrol, a well-known grapevine polyphenolic compound which possesses potent antioxidant and antiaging activities as well as a protective action on skin, is a good example of such plant secondary metabolites. Resveratrol and its oligomeric derivatives are used by several companies of cosmetic products but their extraction from vine stems and similar vegetal sources remains difficult. Therefore grapevine cell suspensions could represent interesting systems for the large-scale bioproduction of those compounds. Here we present an update of the methods used for the production of phytostilbenes by using grapevine cell cultures and the results obtained

Evolution of the alpine Critical Zone since the Last Glacial Period using Li isotopes from lake sediments

Comprehending and predicting the way humans affect the Earth's Critical Zone remains a challenge. An understanding of the past changes resulting from human and non-human influences in the dynamics of the Critical Zone is crucial. Here, we use a retrospective approach to address this question based on a new lithium (Li) isotope record from the Late Glacial Period to the present from a pre-Alpine lake sediment sequence (Lake La Thuile, France). Coupled with the lake sediment archive, the investigation of present-day soils in the lake catchment suggests that lake sediments are not necessarily recording the erosoin of topsoil in the catchment. Our findings indicate that soil particles can be sorted during transportation to the lake, with finer particles being preferentially mobilized, highlighting the influence of fine particle transport on the Li isotope signature of soils and lake sediments. Characterized by low Li isotope signatures, changes in weathering signatures in lake sediments can be amplified by the combined effect of soil development and selective transport. In the La Thuile catchment, soil development was limited during the Late Glacial Period, whereas it became a dominant process during the Holocene climatic optimum together with enhanced selective transport of fine particles. Human activities since 3,000–4,000 yr cal BP induced a strong perturbation hindering both soil formation and selective transport by reinforcing erosion rates. After a period of topsoil destruction caused by intense deforestation and agriculture, lake Li isotopes record the evolution of soil profiles associated with changes in agricultural practices

Organization and function of the plant pleiotropic drug resistance ABC transporter family

Among the ABC transporters, the pleiotropic drug resistance (PDR) family is particular in that its members are found only in fungi and plants and have a reverse domain organization, i.e., the nucleotide binding domain precedes the transmembrane domain. In Arabidopsis and rice, for which the full genome has been sequenced, the family of plant ABC transporters contains 15 and 23 PDR genes, respectively, which can be tentatively organized using the sequence data into five subfamilies. Most of the plant PDR genes so far characterized belong to subfamily I and have been shown to be involved in responses to abiotic and biotic stress, in the latter case, probably by transporting antimicrobial secondary metabolites to the cell surface. Only a single subfamily II member has been characterized. Induction of its expression by iron deficiency suggests its involvement in iron deficiency stress, thus, enlightening a new physiological role for a PDR gene. (c) 2005 Federation of European Biochemical Societies. Published by Else-tier B.V. All rights reserved

Comparing alternative tracing measurements and mixing models to fingerprint suspended sediment sources in a mesoscale Mediterranean catchment

International audiencePurposeKnowledge of suspended sediment provenance in mesoscale catchments is important for applying erosion control measures and best management practices as well as for understanding the processes controlling sediment transport in the critical zone. As suspended sediment fluxes are highly variable in time, particularly given the variability of soil and rainfall properties in mesoscale catchments, knowledge of sediment provenance at high temporal resolution is crucial.Materials and methodsSuspended sediment fluxes were analyzed at the outlet of a 42-km2 Mediterranean catchment belonging to the French critical zone observatory network (OZCAR). Spatial origins of the suspended sediments were analyzed at high temporal resolution using low-cost analytical approaches (color tracers, X-ray fluorescence, and magnetic susceptibility). As the measurements of magnetic susceptibility provide only one variable, they were used for cross-validation of the results obtained with the two alternative tracing methods. The comparison of the tracer sets and three mixing models (non-negative least squares, Bayesian mixing model SIMMR, and partial least squares regression) allowed us to estimate different sources of errors inherent in sediment fingerprinting studies and to assess the challenges and opportunities of using these fingerprinting methods.Results and discussionAll tracer sets and mixing models could identify marly badlands as the main source of suspended sediments. However, the percentage of source contributions varied between the 11 flood events in the catchment. The mean contribution of the badlands varied between 74 and 84%; the topsoils on sedimentary geology ranged from 12 to 29% and the basaltic topsoils from 1 to 8%. While for some events the contribution remained constant, others showed a high within-event variability of the sediment provenance. Considerable differences in the predicted contributions were observed when different tracer sets (mean RMSE 19.9%) or mixing models (mean RMSE 10.1%) were used. Our result shows that the choice of the tracer set was more important than the choice of the mixing model.ConclusionsThese results highlighted the importance of using multi-tracer multi-model approaches for sediment fingerprinting in order to obtain reliable estimates of source contributions. As a given fingerprinting approach might be more sensitive to one type of error, i.e., source variability, particle size selectivity, multi-tracer ensemble predictions allow to detect and quantify these potential biases. High sampling resolution realized with low-cost methods is important to reveal within- and between-event dynamics of sediment fluxes and to obtain reliable information of main contributing sources

Identification of a Nicotiana plumbaginifolia plasma membrane H(+)-ATPase gene expressed in the pollen tube.

In Nicotiana plumbaginifolia, plasma membrane H(+)-ATPases (PMAs) are encoded by a gene family of nine members. Here, we report on the characterization of a new isogene, NpPMA5 (belonging to subfamily IV), and the determination of its expression pattern using the beta-glucuronidase (gusA) reporter gene. pNpPMA5-gusA was expressed in cotyledons, in vascular tissues of the stem (mainly in nodal zones), and in the flower and fruit. In the flower, high expression was found in the pollen tube after in vitro or in vivo germination. Northern blotting analysis confirmed that NpPMA5 was expressed in the pollen tube contrary to NpPMA2 (subfamily I) or NpPMA4 (subfamily II), two genes highly expressed in other tissues. The subcellular localization of PM H(+)-ATPase in the pollen tube was analyzed by immunocytodecoration. As expected, this enzyme was localized to the plasma membrane. However, neither the tip nor the base of the pollen tube was labeled, showing an asymmetrical distribution of this enzyme. This observation supports the hypothesis that the PM H(+)-ATPase is involved in creating the pH gradient that is observed along the pollen tube and is implicated in cell elongation. Compared to other plant PM H(+)-ATPases, the C-terminal region of NpPMA5 is shorter by 26 amino acid residues and is modified in the last 6 residues, due to a sequence rearrangement, which was also found in the orthologous gene of Nicotiana glutinosa, a Nicotiana species distant from N. plumbaginifolia and Petunia hybrida and Lycopersicon esculentum, other Solanacae species. This modification alters part of the PM H(+)-ATPase regulatory domain and raises the question whether this isoform is still regulated

NtPDR1, a plasma membrane ABC transporter from Nicotiana tabacum, is involved in diterpene transport.

ATP-binding cassette transporters are involved in the active transport of a wide variety of metabolites in prokaryotes and eukaryotes. One subfamily, the Pleiotropic Drug Resistance (PDR) transporters, or full-size ABCG transporters, are found only in fungi and plants. NtPDR1 was originally identified in Nicotiana tabacum suspension cells (BY2), in which its expression was induced by microbial elicitors. To obtain information on its expression in plants, we generated NtPDR1-specific antibodies and, using Western blotting, found that this transporter is localized in roots, leaves, and flowers and this was confirmed in transgenic plants expressing the ß-glucuronidase reporter gene fused to the NtPDR1 promoter region. Expression was seen in the lateral roots and in the long glandular trichomes of the leaves, stem, and flowers. Western blot analysis and in situ immunolocalization showed NtPDR1 to be localized in the plasma membrane. Induction of NtPDR1 expression by various compounds was tested in N. tabacum BY2 cells. Induction of expression was observed with the hormones methyl jasmonate and naphthalene acetic acid and diterpenes. Constitutive ectopic expression of NtPDR1 in N. tabacum BY2 cells resulted in increased resistance to several diterpenes. Transport tests directly demonstrated the ability of NtPDR1 to transport diterpenes. These data suggest that NtPDR1 is involved in plant defense through diterpene transport

Evolution of the alpine Critical Zone since the Last Glacial Period using Li isotopes from lake sediments

International audienceComprehending and predicting the way humans affect the Earth's Critical Zone remains a challenge. An understanding of the past changes resulting from human and non-human influences in the dynamics of the Critical Zone is crucial. Here, we use a retrospective approach to address this question based on a new lithium (Li) isotope record from the Late Glacial Period to the present from a pre-Alpine lake sediment sequence (Lake La Thuile, France). Coupled with the lake sediment archive, the investigation of present-day soils in the lake catchment suggests that lake sediments are not necessarily recording the erosoin of topsoil in the catchment. Our findings indicate that soil particles can be sorted during transportation to the lake, with finer particles being preferentially mobilized, highlighting the influence of fine particle transport on the Li isotope signature of soils and lake sediments. Characterized by low Li isotope signatures, changes in weathering signatures in lake sediments can be amplified by the combined effect of soil development and selective transport. In the La Thuile catchment, soil development was limited during the Late Glacial Period, whereas it became a dominant process during the Holocene climatic optimum together with enhanced selective transport of fine particles. Human activities since 3,000-4,000 yr cal BP induced a strong perturbation hindering both soil formation and selective transport by reinforcing erosion rates. After a period of topsoil destruction caused by intense deforestation and agriculture, lake Li isotopes record the evolution of soil profiles associated with changes in agricultural practices

Pedogenesis modification during the Anthropocene: Quantitative and qualitative soil assessment from lake sediment archives

PosterInternational audienc