Cardenolides in Seeds: Exploring the Legacy of Tadeus Reichstein.

The common milkweed is widespread in North America and produces cardenolide toxins that deter herbivores by targeting the transmembrane enzyme Na/K-ATPase. In 1979, Nobel Laureate Tadeus Reichstein elucidated the structure of novel cardenolides isolated from roots and proposed structures for several other cardenolides that could not be confirmed. In this study, we investigate the cardenolide composition of seeds, focusing on their abundance and inhibitory potency on the sensitive porcine Na/K-ATPase and that of the highly resistant large milkweed bug, .

Plant chemical diversity enhances defense against herbivory.

Multiple hypotheses have been put forth to understand why defense chemistry in individual plants is so diverse. A major challenge has been teasing apart the importance of concentration vs. composition of defense compounds and resolving the mechanisms of diversity effects that determine plant resistance against herbivores.

Long-living transients in ecological models: Recent progress, new challenges, and open questions.

Traditionally, mathematical models in ecology placed an emphasis on asymptotic, long-term dynamics. However, a large number of recent studies highlighted the importance of transient dynamics in ecological and eco-evolutionary systems, in particular 'long transients' that can last for hundreds of generations or even longer. Many models as well as empirical studies indicated that a system can function for a long time in a certain state or regime (a 'metastable regime') but later exhibits an abrupt transition to another regime not preceded by any parameter change (or following the change that occurred long before the transition).

Potent Nitrogen-containing Milkweed Toxins are Differentially Regulated by Soil Nitrogen and Herbivore-induced Defense.

Theories have been widely proposed and tested for impacts of soil nitrogen (N) on phytochemical defenses. Among the hundreds of distinct cardenolide toxins produced by milkweeds (Asclepias spp.), few contain N, yet these appear to be the most toxic against specialist herbivores.