Biology subjects

Noel, G.

Publications and source records attributed to Noel, G..

6 recordsLinked to original sources

bioRxiv2026

Carabid beetle communities along a gradient of agroecological systems: disentangling the roles of pesticides and soil tillage

The potential of alternative agricultural systems, such as organic or conservation agriculture, for biodiversity restoration has been widely investigated. However, variability of practices within each of these two categories of agricultural system has rarely been accounted for. Furthermore, these systems have most often been studied separately, isolating either organic or conservation agriculture (itself often reduced to a soil tillage reduction), and rarely analyzing these systems side by side. This study attempts to disentangle these multiple interrelationships by sampling carabid beetles in a network of 48 commercial Belgian farms including organic agriculture (OA), conservation agriculture (CA), farms combining the two approaches (OCA) and farms applying conventional practices (CVA). In each farm, we sampled carabids using pitfall and emergence traps in one winter cereal field and collected a detailed description of crop management practices. We found that community composition was primarily structured by seasonality early in the season (March, April) followed by convergence (May, June) driven by the aggregation of the most dominant species. Based on agroecosystem classification, organic certification (i.e., the absence of synthetic pesticide use) exerted a twofold stronger effect than application of conservation agriculture principles (i.e., reduced or no soil tillage) on carabid beetle community composition. Notably, OCA supported carabid assemblages that were structurally distinct from those of CA and CVA. Furthermore, carabid communities associated with OA differed significantly in composition from those of CVA. Observed and estimated species richness were also significantly higher in OCA than in CA and CVA, while OA differed from CVA only for observed richness. Beyond differences among agricultural systems, community responses were associated with specific management practices, which explained nearly a quarter of the compositional variation with significant influence of the duration since organic conversion and the frequency of synthetic pesticide application. Carabid abundances were negatively affected by synthetic pesticides and moldboard ploughing, whereas richness was more strongly related to the time since conversion to OA, cover crops, and organic amendments. Overall, these results position synthetic inputs and time since conversion as the main filters over carabid communities. Our study highlights the importance of jointly considering system level analyses and detailed management practices to better understand the complex relationships between agricultural practices and carabid communities.

ecology↗

bioRxiv2024

Genomic mosaicism reveals developmental organization of trunk neural crest-derived ganglia

The neural crest generates numerous cell types, but conflicting results leave developmental origins unresolved. Here using somatic mosaic variants as cellular barcodes, we infer embryonic clonal dynamics of trunk neural crest, focusing on the sensory and sympathetic ganglia. From three independent adult neurotypical human donors, we identified 1,278 mosaic variants using deep whole-genome sequencing, then profiled allelic fractions in 187 anatomically dissected ganglia. We found a massive rostrocaudal spread of progenitor clones specific to sensory or sympathetic ganglia, which unlike in the brain, showed robust bilateral distributions. Computational modeling suggested neural crest progenitor fate specification preceded delamination from neural tube. Single-cell multiomic analysis suggested both neurons and glia contributed to the rostrocaudal clonal organization. CRISPR barcoding in mice and live imaging in quail embryos confirmed these clonal dynamics across multiple somite levels. Our findings reveal an evolutionarily conserved clonal spread of cells populating peripheral neural ganglia. Highlights- Genetic mosaicism and real-time imaging reveal trunk neural crest cellular dynamics. - DRG or SG cells from different axial levels are more lineage-related than from the same level. - Cell fate specification of trunk neural crest progenitors occurs before neural tube delamination. - These aspects of clonal organization are evolutionarily conserved across mammals and avians.

developmental biology↗

bioRxiv2023

Evolutionarily diverse origins of honey bee deformed wing viruses

Novel transmission routes can allow infectious diseases to spread, often with devastating consequences. Ectoparasitic varroa mites vector a diversity of RNA viruses and, having switched hosts from the eastern to western honey bees (Apis cerana to Apis mellifera). They provide an opportunity to explore how novel transmission routes shape disease epidemiology. As the principal driver of the spread of Deformed Wing Viruses (mainly DWV-A and DWV-B), varroa infestation has also driven global honey bee health declines. The more virulent DWV-B strain has been replacing the original DWV-A strain in many regions over the past two decades. Yet, how these viruses originated and spread remains poorly understood. Here we use a phylogeographic analysis based on whole genome data to reconstruct the origins and demography of DWV spread. We found that, rather than reemerging in western honey bees after varroa switched hosts, as suggested by previous work, DWV-A most likely originated in Asia and spread in the mid-20th century. It also showed a massive population size expansion following the varroa host switch. By contrast, DWV-B was most likely acquired more recently from a source outside Asia, and appears absent from eastern honey bees, the original varroa host. These results highlight the dynamic nature of viral adaptation, whereby a vectors host switch can give rise to competing and increasingly virulent disease pandemics. The evolutionary novelty and rapid global spread of these host-virus interactions, together with observed spillover into other species, illustrate how increasing globalisation poses urgent threats to biodiversity and food security.

evolutionary biology↗

bioRxiv2021

Nest aggregations of wild bees and apoid wasps in urban pavements: a street life to be promoted in urban planning

In the last 10 years, knowledges of wild bees and apoid wasps community dynamics have gained interest in urban ecology focusing on the availability of floral resources in cities. Although understudied, the urban environment impacts the conditions of their nesting sites. Recent observations in the Brussels-Capital Region (Belgium) showed that urban pavements can be a novel nesting opportunity for Hymenoptera ground-nesting species such as wild bees and apoid wasps. Here, using citizen science, we investigated the richness of ground-nesting species living under urban pavements, the preferences of the sidewalk joint size related to ground-nesting species size and for sidewalk type or for soils texture under the pavements on the nesting site selection. A total of 22 species belonging to 10 Hymenoptera families of wild bees and digger wasps with their associated kleptoparasites were identified on 89 sites in Brussels. Sandstone setts or concrete slabs with an unbound joint size around 1 cm were found to be best suitable urban pavements for the ground-nesting species. The soil texture under the pavement was highly sandy among our samples. Finally, we also suggest engineering management guidelines to support bee and wasp species nesting under urban pavement in highly urbanized areas. Such observations pave the way for much research in the field of urban ecology to conceive multifunctional pavement promoting biodiversity.

ecology↗

bioRxiv2021

Multi-omics approach reveals new insights into the gut microbiome of Galleria mellonella (Lepidoptera:Pyralidae) exposed to polyethylene diet

The current plastic pollution throughout the world implies a crucial optimization of its (bio)degradation processes. In order to identify plastic degrading bacteria and associated enzymes, the gut microbiota of insects has raised interest. Some entomological models such as Tenebrio molitor (L. 1758), Plodia interpunctella (Hubner 1813) or Galleria mellonella (L. 1758) have the ability to ingest and degrade polyethylene. Then, it is promising to identify the composition and the role of the gut microbiota in this process. This study takes part in this issue by investigating G. mellonella as a biological model feeding with a polyethylene diet. Gut microbiome samples were processed by high throughput 16S rRNA sequencing, and Enterococcaceae and Oxalobacteraceae were found to be the major bacterial families. At low polyethylene dose, we detect no bacterial community change and no amplicon sequence variant associated with the polyethylene diet suggesting microbiome resilience. The functional analysis of insects gut content was promising for the identification of plastic degrading enzymes such as the phenylacetaldehyde dehydrogenase which participate in styrene degradation. This study allows a better characterization of the gut microbiota of G. mellonella and provides a basis for the further biodegradation study of polyethylene based on the microorganism valorization from insect guts.

microbiology↗

bioRxiv2021

Human breast milk enhances intestinal mucosal barrier function and innate immunity in a pediatric human enteroid model

Breastfeeding has been associated with long lasting health benefits. Nutrients and bioactive components of human breast milk promote cell growth, immune development, and shield the infant gut from insults and microbial threats. The molecular and cellular events involved in these processes are ill defined. We have established human pediatric enteroids and interrogated maternal milks impact on epithelial cell maturation and function in comparison with commercial infant formula. Colostrum applied apically to pediatric enteroid monolayers reduced ion permeability, stimulated epithelial cell differentiation, and enhanced tight junction function by upregulating occludin expression. Breast milk heightened the production of antimicrobial peptide -defensin 5 by goblet and Paneth cells, and modulated cytokine production, which abolished apical release of pro-inflammatory GM-CSF. These attributes were not found in commercial infant formula. Epithelial cells exposed to breast milk elevated apical and intracellular pIgR expression and enabled maternal IgA translocation. Proteomic data revealed a breast milk-induced molecular pattern associated with tissue remodeling and homeostasis. Using a novel ex vivo pediatric enteroid model, we have identified cellular and molecular pathways involved in human milk-mediated improvement of human intestinal physiology and immunity.

immunology↗