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Andrea Diana Fernandes de Abreu

"Quick guide to C. elegans and the mystery of the 40 insulin-like peptides"

 Abstract
Nature's Gift to Science” was the title of Sydney Brenner’s Nobel lecture in 2002 in homage to C. elegans. Indeed, since the early 70’s, the role of this model organism in a broad range of disciplines has been immense. Therefore, I will introduce in the first part of the talk, some aspects of working with this nematode and in the second part I will very briefly speak about my former post-doc.
C. elegans has 40 insulin-like peptides (ILPs) that regulate several processes, including longevity, dauer formation, pathogen resistance and thermotolerance. Small-scale studies have shown that insulin-like peptides can regulate each other. But how multiple ILPs interact to coordinate physiology is poorly understood.
We systematically evaluated the effect of 35 different ILP deletion mutants in 8 physiological processes. We also analyzed the expression of each ILP in the 35 ILP mutants. The results revealed the ILPs are organized into a network with specific ILP-to-ILP regulation. Furthermore, integrative analysis of our systematic datasets indicates that ILPs cooperate not only via compensation but also via feedback, feed-forward and cross-talk functionality. We believe these principles may also apply to multi-gene families of intercellular signals in different animals.

Jean-Jacques Remy

"A causal link between the time-window of chemosensory plasticity and the rate of chemosensory adaptation in C. elegans"

Abstract
Animal behaviors result from a continuous interplay between genetically programmed and newly acquired information. Animals acquire experience usually during timely limited periods of development called critical periods of plasticity. The time-windows of these critical periods are highly variable amongst animal species. Typically, inside a given genus – as birds and primates - species with short learning periods must express rapidly their innate behaviors to survive, while species with long learning and nurturing periods have usually higher cognitive abilities, and more sophisticated behaviors and cultures. Nothing is known about the mechanisms that control the relationships between behavior ontogeny, behavior plasticity and behavior evolution through assimilation of learned behaviors as innate. We tried to address these questions using the chemosensory behavior in the C. elegans nematode.  We identified mutations that affect the temporal settings of chemo-attractive responses, and were able to establish a causal relationship between the chemosensory plasticity time-windows and the rate at which nematodes populations assimilate early chemosensory experience as new stably inherited chemosensory behavior.