Diversity of aphyllous Vanilla species in the south-west Indian Ocean region: a challenge for orchid taxonomy, evolution and conservation research

The pantropical genus Vanilla is a member of the Orchidaceae family, one of the largest and most ancient families of angiosperms in the world. It originated in America and differentiated in America, Africa and Asia. About 126 species of Vanilla have been catalogued since the discovery of the genus: 25 can be found in Africa, 31 are indigenous to Asia, New Guinea and Pacific islands, and 70 are distributed in tropical America. The south-west Indian Ocean (SWIO) region, a biodiversity hotspot for orchids, is home to 9 native species of the genus with 7 aphyllous species and 2 leafy species. These 7 aphyllous are represented by two species with yellow flowers (V. humblotii, V. perrieri) and five species with white flowers (V. madagascariensis, V. bosseri, V. decaryana, V. phalaenopsis, V. roscheri). Recent molecular phylogenetic studies showed that these aphyllous species form a recent monophyletic group. Morphological descriptions of these aphyllous species in databases (MNHN, RBG Kew, Tropicos..) and in scientific publications are based on a limited number of individuals. The morphological traits (petals, sepals, label, and stems) are very similar between species and do not provide reliable identification despite possible flower size differences. Moreover, the species have more or less the same flowering period (October-December) and their geographical distribution areas overlap in Madagascar, increasing the probability of finding some sympatric species such as V. madagascariensis, V. bosseri and V. perrieri, and therefore possible hybrids. As the available information on genetic structuring and phylogeny of these species is insufficient, the resolution of their taxonomy is problematic. Aphyllous Vanilla species from the SWIO islands are thus an excellent model for understanding the evolution of orchids. For their conservation and to confirm the identity of these aphyllous species, an integrated approach with classical taxonomy using a large number of samples, intense fieldwork on biology and ecology, and molecular studies using variable markers is currently underway

Antitumor Mechanism of the Essential Oils from Two Succulent Plants in Multidrug Resistance Leukemia Cell

Drug resistance remains a major challenge in the treatment of cancer. The multiplicity of the drug resistance determinants raises the question about the optimal strategies to deal with them. Essential oils showed to inhibit the growth of different tumor cell types. Essential oils contain several chemical classes of compounds whose heterogeneity of active moieties can help prevent the development of drug resistance. In the present paper, we analyzed, by gas chromatography-mass spectrometry the chemical composition of the essential oil of the leaves of Kalanchoe beharensis obtained by hydrodistillation and compared the chemical composition of its essential oil with that of Cyphostemma juttae. Our results demonstrated the anticancer and proapoptotic activities of both species against acute myeloid leukemia on an in vitro model and its multidrug resistant variant involving NF-κB pathway. The essential oils of both species produced a significant decrease in many targets of NF-κB both at mRNA and protein levels. The results corroborate the idea that essential oils may be a good alternative to traditional drugs in the treatment of cancer, especially in drug resistant cancer

Twenty-Year Development of Zoological and Botanical Research Topics in The University of Antananarivo: Implication for Future Challenges of Biodiversity Conservation

The Department of Zoology and Animal Biodiversity (DZAB) and the Department of Plant Ecology and Biology (DPEB), Faculty of Science, University of Antananarivo, Madagascar), have played a major role in the education of the national natural scientists since 1990. To assess their roles in fauna and flora conservation, the number of the graduated students per year, the number of research done by the two departments in Madagascar, the development of research topics, the type of ecosystem, and the type of jobs after the academic education were explored from 1995 to 2015. As results, those departments, through different partnerships and collaborations with overseas institutions (that include universities, associations and NGOs) have collected large quantity of biological data corresponding to 570 doctoral dissertations and master theses (276 from the field of zoology and 294 from the field of botany). 11 students defended theses on genetics, seven on Plant-Animal interactions and only one on Animal physiology, probably due to high cost of modern biological technologies or a bias in funding priorities. 95% of the studies were funded by international or national private agencies. The number of research undertaken by our students in both fields of zoology and botany has increased during the last decade. About 60% of the studies have been carried out in dense forest area in which research topics are less diversified than in other areas like coastal forest area, wetland, town/city, etc. Only 7% were carried out in marine, mangrove and coastal forest areas. Concerning the employment status of our graduates after the graduation, 125 among 210 graduates answered to the questionnaires and 64% of them are working with government or private agencies serving as consultants or permanent jobs on conservation. Thus, the two departments have played crucial roles in training a meritable generation of national natural scientists which are able to provide scientific expertise to support sustainable conservation. These departments can also be identified as a good networking system through fostering collaboration with the foreign institutions, and can be considered as data collectors. The biological data obtained by our students could be used and analyzed by stakeholders for biodiversity planning and monitoring process. The results from this study are expected to help the policy-makers and the users of information determine and set the conservation priorities in the future. To conclude, this study examines the different roles played by DZAB and DPEB in conserving Madagascar biodiversity, and presents their future challenges for improving the quality of education and research at the departments

MODULATION DU DEVELOPPEMENT DES EMBRYONS SOMATIQUES DE PIN MARITIME (PINUS PINASTER AIT.) EN FONCTION DES CONDITIONS DE CULTURE

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

In Vitro Modulation of P-Glycoprotein Activity by Euphorbia intisy Essential Oil on Acute Myeloid Leukemia Cell Line HL-60R

Euphorbia species have a large spectrum of traditional medicinal uses. We tested the biological activities of the essential oil (EO) of Euphorbia intisy Drake in an acquired multidrug resistance leukemia model to assess whether the EO obtained by hydrodistillation of stems was able to reverse the resistant phenotype. HL-60R cell lines are characterized by the overexpression of P-glycoprotein (P-gp), inhibitors of apoptosis proteins (IAPs) and constitutive expression of NF-κB. EO chemical composition was determined by GC/MS analysis; cytotoxic activity of EO by MTS assay alone or in combination with doxorubicin; pro-apoptotic effect and doxorubicin accumulation were analyzed by flow cytometry; P-gp ATPase activity was measured by P-gp-Glo™ assay systems kit. The ability to inhibit NF-κB and its target genes was also assessed. E. intisy EO exhibited a comparable cytotoxic effect and ability to block P-gp in both the HL-60 and its MDR variant HL-60R. In addition, EO suppressed P-gp protein expression and significantly downregulated MDR1 mRNA level, as well as some IAPs proteins, probably through the inhibition of NF-κB. Our results suggest that E. intisy EO could reverse P-gp-mediated drug resistance in tumor cells acting as a chemosensitizing agent

Essential Oil Composition of Alluaudia procera and in Vitro Biological Activity on Two Drug-Resistant Models

Drug resistance is a major obstacle in antibiotic and antitumor chemotherapy. In response to the necessity to find new therapeutic strategies, plant secondary metabolites including essential oils (EOs) may represent one of the best sources. EOs in plants act as constitutive defenses against biotic and abiotic stress, and they play an important role in the pharmacology for their low toxicity, good pharmacokinetic and multitarget activity. In this context, natural products such as EOs are one of the most important sources of drugs used in pharmaceutical therapeutics. The aim of this paper was to identify the chemical composition of the essential oil of Alluaudia procera leaves, obtained by hydrodistillation and analysed by gas chromatography-mass spectrometry, and to verify its biological activities on acute myeloid leukemia cancer cell HL60 and its multidrugresistant variant HL60R and the Gram-positive Staphylococcus aureus exhibiting multi-antibiotic resistance. We speculate that cytotoxic and antibiotic effects observed in the tested resistant models may be due to the coordinate activities of forty compounds detected or to the C16 macrocyclic lactones which are the major ones (30%). Our data confirm the possibility of using EOs as therapeutic strategies in resistant models is due to the heterogeneous composition of the oils themselves