Project description:Diversification of defense-related compounds is a plant defense mechanism against the diverse array of natural enemies in the course of evolution, and is known to involve various sources of tissue. Here a large-scale survey of gene expression is conducted from three different sources of tissue; needles, phloem with the attached bark, and xylem, with an emphasis on the expression of the secondary metabolites of the core phenylpropanoid pathway and derivative pathways, taken together as phenolic defense-related compounds. Five species of spruce; P. abies, P. glauca, P. jezoensis, P. mariana, and P. omorika, spanning much of their known phylogeny, are chosen for cross-species microarray hybridizations. The objectives are: first) to explore the tissue-related differences in the expression of phenolic genes and their coherent role in tree defense; second) to describe the diversification trends in the expression of phenolic gene families with respect to their position in the pathway; and third) to infer the mode of evolution underlying the expression of the selected genes.
Project description:Isolation and dereplication of antitubercular compounds produced by South African fila-mentous actinobacteria by HPLC-MS/MS anal-ysis of their zones of growth inhibition
Project description:Bulb, leaf, scape and flower samples of British bluebells (<i>Hyacinthoides non-scripta</i>) were collected regularly for one growth period. Methanolic extracts of freeze-dried and ground samples showed antitrypanosomal activity, giving more than 50% inhibition, for 20 out of 41 samples. High-resolution mass spectrometry was used in the dereplication of the methanolic extracts of the different plant parts. The results revealed differences in the chemical profile with bulb samples being distinctly different from all aerial parts. High molecular weight metabolites were more abundant in the flowers, shoots and leaves compared to smaller molecular weight ones in the bulbs. The anti-trypanosomal activity of the extracts was linked to the accumulation of high molecular weight compounds, which were matched with saponin glycosides, while triterpenoids and steroids occurred in the inactive extracts. Dereplication studies were employed to identify the significant metabolites via chemotaxonomic filters and considering their previously reported bioactivities.
Project description:In this study, we investigated seven medicinal plant species from French Guiana as potential sources of novel antitubercular compounds. Using ultrasound-assisted extraction, liquid-liquid partitioning, and UHPLC-HRMS/MS, we created a library of 72 samples screened against Mycobacterium tuberculosis H37Ra. The most active fractions were the non-polar extracts from Indigofera suffruticosa, Tetradenia riparia, and Zingiber zerumbet.
Through bioactivity-guided molecular networking, we integrated metabolomic and bioassays data to prioritize and annotate active metabolites, primarily flavonoids. Computational tools (GNPS, SIRIUS, TIMA-R) further enhanced structural prediction and dereplication. This approach offers an efficient strategy to identify known and novel bioactive compounds without requiring exhaustive isolation.