Four terpene synthases contribute to the generation of chemotypes in tea tree (Melaleuca alternifolia)

BACKGROUND: Terpene rich leaves are a characteristic of Myrtaceae. There is significant qualitative variation in the terpene profile of plants within a single species, which is observable as "chemotypes". Understanding the molecular basis of chemotypic variation will help explain how such variation is maintained in natural populations as well as allowing focussed breeding for those terpenes sought by industry. The leaves of the medicinal tea tree, Melaleuca alternifolia, are used to produce terpinen-4-ol rich tea tree oil, but there are six naturally occurring chemotypes; three cardinal chemotypes (dominated by terpinen-4-ol, terpinolene and 1,8-cineole, respectively) and three intermediates. It has been predicted that three distinct terpene synthases could be responsible for the maintenance of chemotypic variation in this species. RESULTS: We isolated and characterised the most abundant terpene synthases (TPSs) from the three cardinal chemotypes of M. alternifolia. Functional characterisation of these enzymes shows that they produce the dominant compounds in the foliar terpene profile of all six chemotypes. Using RNA-Seq, we investigated the expression of these and 24 additional putative terpene synthases in young leaves of all six chemotypes of M. alternifolia. CONCLUSIONS: Despite contributing to the variation patterns observed, variation in gene expression of the three TPS genes is not enough to explain all variation for the maintenance of chemotypes. Other candidate terpene synthases as well as other levels of regulation must also be involved. The results of this study provide novel insights into the complexity of terpene biosynthesis in natural populations of a non-model organism.The research was funded by the Australian Research Council (ARC) Discovery Program (DP14101755), the Australian Government Rural Industries Research and Development Corporation (RIRDC) and the Australia Tea Tree Industry Association (ATTIA). Grants from the Go8-DAAD Research Scheme and a Humboldt Research Award from the Alexander von Humboldt Foundation to WJF underpinned this collaborative research. Each of the funding bodies granted the funds based on a research proposal. They had no influence over the experimental design, data analysis or interpretation, or writing the manuscript

Mutations in the ELANE Gene are Associated with Development of Periodontitis in Patients with Severe Congenital Neutropenia

# The Author(s) 2011. This article is published with open access at Springerlink.com Background Patients with severe congenital neutropenia (SCN) often develop periodontitis despite standard medical and dental care. In light of previous findings that mutations in the neutrophil elastase gene, ELANE, are associated with more severe neutropenic phenotypes, we hypothesized an association between the genotype of SCN and development of periodontitis. Methods Fourteen Swedish patients with SCN or cyclic neutropenia harboring different genetic backgrounds were recruited for periodontal examination. Peripheral blood, gingival crevicular fluid (GCF), and subgingival bacterial Thomas Modéer and Katrin Pütsep have contributed equally to the study

Desempenho e hematologia de tilápias-do-nilo alimentadas com Saccharomyces cerevisiae e vacinadas contra Streptococcus agalactiae

O objetivo deste trabalho foi avaliar a inter-relação entre a suplementação alimentar com parede celular de Saccharomyces cerevisae e a vacinação contra Streptococcus agalactiae e seu efeito sobre o desempenho produtivo e as variáveis hematológicas de tilápia-do-nilo (Oreochromis niloticus). Oitenta e quatro tilápias-do-nilo foram distribuídas em 12 caixas de fibra (n=7), em arranjo fatorial 2x2x3, correspondente a dois níveis de suplementação com parede celular de levedura, dois tipos de inoculação e três tempos de avaliação. Os peixes foram alimentados durante 77 dias. A vacinação dos peixes foi realizada 60 dias após o início da alimentação. Quinze dias após a vacinação, todos os peixes foram submetidos ao desafio com cepa viva de S. agalactiae, e 6, 24 e 48 horas após o desafio, o sangue foi colhido da veia caudal para avaliações. Peixes alimentados com ração suplementada apresentam maior ganho de peso e taxa de crescimento específico, e a interação entre os efeitos da dieta e da vacinação resulta em maiores taxas de hematócrito, hemoglobina e leucócitos

Electrosynthèse organique (fonctionnalisation allylique et aromatisation électro-assistées d'oléfines par les radicaux aminoxyles)

Le présent mémoire est consacré à l électrosynthèse catalysée par les radicaux aminoxyles, appliquée à la fonctionnalisation et à l aromatisation d oléfines activées. La première partie concerne l étude de la réactivité de la forme oxoammonium du TEMPO vis-à-vis d oléfines modèles diversement activées. Les études voltammétriques et cinétiques font l objet de comparaisons systématiques. En présence d eau la fonctionnalisation allylique est obtenue. Dans le cas des cyclohexadiènes conjugués et non conjugués, l aromatisation est la principale voie d oxydation. L étude des paramètres expérimentaux permet de proposer un mécanisme réactionnel commun dans lequel l arrachement d hydrure allylique par les ions oxoammoniums est l étape clé. La deuxième partie du mémoire traite de l utilisation du système électrocatalytique pour l oxydation d oléfines grasses poly-insaturées. Les produits obtenus sont fonctionnalisés et présentent une conjugaison du système vinylique.The present work concern the electrosynthesis mediated by nitroxyl radicals, applied to the functionalization and aromatisation of activated olefins. The first part is a study of the reactivity of the oxoammonium form of TEMPO on several olefins more or less activated. Voltametric and kinetic studies are systematically compared in order to obtain informations on the reactivity. In presence of water, the allylic functionalization is obtained. In the case of conjugated and not conjugated cyclohexadiens, the aromatisation is the principal way of oxidation. The studies of experimental parameters allowed us to suggest a common mechanism were the key step is an allylic hydride abstraction. The second part of the work concerns the use of the electrocatalytic system for the oxidation of polyunsaturated fatty esters. The products obtained are functionalized in allylic position and present a conjugation of the vinylic system.POITIERS-BU Sciences (861942102) / SudocSudocFranceF