Members of the cholecystokinin (CCK)/gastrin family of peptides, including the arthropod sulfakinins, and their cognate receptors, play an important role in the regulation of feeding behavior and energy homeostasis. Despite many efforts after the discovery of CCK/gastrin immunoreactivity in nematodes 23 yr ago, the identity of these nematode CCK/gastrin-related peptides has remained a mystery ever since. The Caenorhabditis elegans genome contains two genes with high identity to the mammalian CCK receptors and their invertebrate counterparts, the sulfakinin receptors. By using the potential C. elegans CCK receptors as a fishing hook, we have isolated and identified two CCK-like neuropeptides encoded by neuropeptide-like protein-12 (nlp-12) as the endogenous ligands of these receptors. The neuropeptide-like protein-12 peptides have a very limited neuronal expression pattern, seem to occur in vivo in the unsulfated form, and react specifically with a human CCK-8 antibody. Both receptors and ligands share a high degree of structural similarity with their vertebrate and arthropod counterparts, and also display similar biological activities with respect to digestive enzyme secretion and fat storage. Our data indicate that the gastrin-CCK signaling system was already well established before the divergence of protostomes and deuterostomes.

1TJ, SJH and EM contributed equally to this work.Abbreviations used: LD, light-dark; GFP, green fluorescent protein; NLP, neuropeptide-like proteins; PDF, pigment dispersing factor; PDH, pigment-dispersing hormones; TBS, Tris-buffered saline; TFA, trifluoracetic acid; VIP, vasoactive intestinal peptide. AbstractThe neuropeptides pigment dispersing factor (PDF) and vasoactive intestinal peptide (VIP) are known as key players in the circadian clock system of insects and mammals, respectively. In this study, we report the discovery and characterization of a widely conserved PDF-like neuropeptide precursor pathway in nematodes. Using a combinatorial approach of biochemistry and peptidomics, we have biochemically isolated, identified and characterized three PDF-like neuropeptides in the free-living nematode Caenorhabditis elegans. The two PDF encoding genes, which were designated pdf-1 and pdf-2, display a very strong conservation within the phylum of nematodes. Many of the PDF expressing cells in C. elegans play a role in the control of locomotion and the integration of environmental stimuli, among which light. Our real-time PCR analysis indicates that both PDF genes are consistently expressed during the day and do not affect each other's expression. The transcription of both PDF genes seems to be regulated by atf-2 and ces-2, which encode bZIP transcription factors homologous to Drosophila vrille and par domain protein 1 (Pdp1e), respectively. Together, our data suggest that the PDF neuropeptide pathway, which seems to be conserved throughout the protostomian evolutionary lineage, might be more complex than previously assumed.

The ectomycorrhizal basidiomycete Suillus luteus (L.:Fr.), a typical pioneer species which associates with young pine trees colonizing disturbed sites, is a common root symbiont found at heavy metal contaminated sites. Three Cd-sensitive and three Cd-tolerant isolates of S. luteus, isolated respectively from non-polluted and a heavy metal-polluted site in Limburg (Belgium), were used for a transcriptomic analysis. We identified differentially expressed genes by cDNA-AFLP analysis. The possible roles of some of the encoded proteins in heavy metal (Cd) accumulation and tolerance are discussed. Despite the high conservation of coding sequences in S. luteus, a large intraspecific variation in the transcript profiles was observed. This variation was as large in Cd-tolerant as in sensitive isolates and may help this pioneer species to adapt to novel environments.

The project "amai!" ("Oh my" in Flemish) implements citizen science methods to co-develop solutions using artificial intelligence (AI) for societal challenges. The project looks for AI solutions in the field of mobility, climate, health, and work, and with the overarching theme of digital inclusion. Citizens and citizen organisations are included in the entire development process of the AI solutions, from sharing their initial ideas and co-defining solutions, to selecting proposals to receive funding to implement the solution, and involvement in the training of the AI solutions. The target audience is people not primarily interested in AI but who are interested in solving societal issues. Citizens are also invited to take part in other activities, such as using creative AI tools and playing the amai! card game. This contribution gives an overview of the approach of amai! and touches upon valuable discussions on this approach during the poster session of the

Citizen science (CS) is rapidly on the rise. This is also the case in Flanders, the Dutch speaking region of Belgium. Little is known about who these citizen scientists in Flanders are, why they take part in CS projects, and how they experience these projects. Answers to these questions would be very valuable for researchers setting up new CS projects. There is also little known about how many researchers know about CS or have experience with CS, and if they have experience with CS, their motivations for choosing a CS approach for their research, as well as barriers that they have faced. Scivil, the Flemish knowledge centre for Citizen Science, carried out two surveys in 2020 to gain insight into these questions: one survey was among citizen scientists and was used to gain insight into the personal characteristics of citizen scientists and their motivations for participating in a CS project. The other survey was conducted among Flemish scientists and probed their knowledge, experiences, and interest in CS. This paper highlights the findings of both surveys as well as the discussion of these findings that took place during the poster session at the

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