Lecture
IBL Spotlight - Somayah Elsayed and Kasper van der Cruijsen
- Date
- Tuesday 18 November 2025
- Time
- Series
- IBL Spotlights
- Location
-
Sylvius
Sylviusweg 72
2333 BE Leiden - Room
- 1.4.31
Speakers
Somayah Elsayed
Ecology-based discovery of novel bioactive microbial natural products
Natural products (NPs) produced by microorganisms, have a deep rooted history and continued essential role in the discovery of new drug molecules, particularly antibiotics and anticancer agents. Microbial NPs applications extend to the agricultural, biotechnological and environmental sector. Traditionally, free-living soil microbes have been used for the discovery of novel bioactive NPs. Nowadays, this strategy results in mostly rediscovery of already known molecules, even though advancements in gene sequencing revealed that microbial genomes encode a plethora of cryptic novel NPs. In my talk, I will show how we alternatively harness microbial ecology, in combination with state-of-the-art metabolomics and genomics, for the discovery of novel bioactive NPs. Our approach not only uncovers novel chemical skeletons, but also rare microbial taxa with unprecedented biosynthetic potential.
Kasper van der Cruijsen
Microbiome and metabolome in onion fields
Interactions with soil microbes are essential for plant health, as they provide nutrients and enhance nutrient uptake. Moreover, soil microbes can influence plant biochemical pathways, contributing to traits such as disease resistance and stress tolerance. Recent studies have shown that soil microbes can substantially alter the composition of both primary and secondary metabolites in plant tissues. However, less is known about how these changes affect the nutritional value of agricultural crops.
This research investigates whether variation within the soil microbiome affects the metabolome, and thereby the nutritional value and quality, of onion bulbs (Allium cepa). A field survey was conducted across agricultural fields in the Netherlands to collect soil samples and onion bulbs for studying microbiome and metabolome variation. Soil microbial composition was analyzed using amplicon sequencing of bacterial (16S) and fungal (ITS) regions, while NMR spectroscopy was applied for untargeted metabolite profiling of onion bulbs. Additionally, a controlled experiment was performed to further examine the relationship between the soil microbiome and onion metabolome. In this presentation, I will show the first results of our work on this topic.
