Publications

Social insects exhibit a high degree of intraspecific behavioral variation. Moreover, they often harbor specialized microbial communities in their gut. Recent studies suggest that these two characteristics of social insects are interlinked: insect behavioral phenotypes affect their gut microbiota composition, partly through exposure to different environments and diet, and in return, the gut microbiota has been shown to influence insect behavior. Here, we discuss the bidirectional relationship existing between intraspecific variation in gut microbiota composition and behavioral phenotypes in social insects.

Reptilian skin coloration is spectacular and diverse, yet little is known about the ontogenetic processes that govern its establishment and the molecular signaling pathways that determine it. Here, we focus on the development of the banded pattern of leopard gecko hatchlings and the transition to black spots in the adult. With our histological analyses, we show that iridophores are present in the white and yellow bands of the hatchling and they gradually perish in the adult skin. Furthermore, we demonstrate that melanophores can autonomously form spots in the absence of the other chromatophores both on the regenerated skin of the tail and on the dorsal skin of the Mack Super Snow (MSS) leopard geckos. This color morph is characterized by uniform black coloration in hatchlings and black spots in adulthood; we establish that their skin is devoid of xanthophores and iridophores at both stages. Our genetic analyses identified a 13-nucleotide deletion in the PAX7 transcription factor of MSS geckos, affecting its protein coding sequence. With our single-cell transcriptomics analysis of embryonic skin, we confirm that PAX7 is expressed in iridophores and xanthophores, suggesting that it plays a key role in the differentiation of both chromatophores. Our in situ hybridizations on whole-mount embryos document the dynamics of the skin pattern formation and how it is impacted in the PAX7 mutants. We hypothesize that the melanophores-iridophores interactions give rise to the banded pattern of the hatchlings and black spot formation is an intrinsic capacity of melanophores in the postembryonic skin.

A comprehensive knowledge of human leukocyte antigen (HLA) molecular variation worldwide is essential in human population genetics research and disease association studies and is also indispensable for clinical applications such as allogeneic hematopoietic cell transplantation, where ensuring HLA compatibility between donors and recipients is paramount. Enormous progress has been made in this field thanks to several decades of HLA population studies allowing the development of helpful databases and bioinformatics tools. However, it is still difficult to appraise the global HLA population diversity in a synthetic way. We thus introduce here a novel approach, based on approximately 2000 data sets, to assess this complexity by providing a fundamental synopsis of the most frequent HLA alleles observed in different regions of the world. This new knowledge will be useful not only as a fundamental reference for basic research, but also as an efficient guide for clinicians working in the field of transplantation.

head formation depends on an organizing center in which Wnt/β-catenin signaling, that plays an inductive role, positively regulates and , with Sp5 limiting expression and Zic4 triggering tentacle formation. Using transgenic lines in which the promoter drives eGFP expression in either the epidermis or gastrodermis, we show that promoter activity is differentially regulated in each epithelial layer. In intact animals, epidermal GFP activity is strong apically and weak along the body column, while in the gastrodermis, it is maximal in the tentacle ring region and maintained at a high level along the upper body column. During apical regeneration, :GFP is activated early in the gastrodermis and later in the epidermis. Alsterpaullone treatment induces a shift in apical expression towards the body column where it forms transient circular figures in the epidermis. Upon (RNAi), GFP activity is down-regulated in the epidermis while bud-like structures expressing GFP in the gastrodermis develop. (RNAi) reveals a negative autoregulation in the epidermis, but not in the gastrodermis. These differential regulations in the epidermis and gastrodermis highlight the distinct architectures of the network in the hypostome, tentacle base and body column of intact animals, as well as in the buds and apical and basal regenerating tips.

After pediatric liver transplantation (pLT), children undergo life-long immunosuppression since reliable biomarkers for the assessment of rejection probability are scarce. In the multicentre (n=7) prospective clinical cohort "ChilSFree" study, we aimed to characterize longitudinal dynamics of soluble and cellular immune mediators during the first year after pLT and identify early biomarkers associated with outcome.

Open wounds pose major infection and mortality risks in animals.1,2 To reduce these risks, many animal species apply antimicrobial compounds on their wounds.1,2,3,4 Ant societies use antimicrobial secretions from the metapleural gland to combat pathogens,5,6,7,8,9,10 but this gland has been lost over evolutionary time in several genera, including Camponotus.11 To understand how infected wounds are handled without the use of antimicrobial secretions from the metapleural gland, we conducted behavioral and microbiological experiments in Camponotus floridanus. When we experimentally injured a worker's leg at the femur, nestmates amputated the injured limb by biting the base (trochanter) of the leg until it was severed, thereby significantly increasing survival compared to ants that did not receive amputations. However, when the experimental injury was more distal (at the tibia), nestmates did not amputate the leg and instead directed more wound care to the injury site. Experimental amputations also failed to improve survival in ants with infected tibia injuries unless the leg was amputated immediately after pathogen exposure. Micro-CT scans revealed that the muscles likely responsible for leg hemolymph circulation are predominantly in the femur. Thus, it is likely that femur injuries, by attenuating hemolymph flow, provide sufficient time for workers to perform amputations before pathogen spread. Overall, this study provides the first example of the use of amputations to treat infected individuals in a non-human animal and demonstrates that ants can adapt their type of treatment depending on the location of wounds.

The claustrum (CLA), a subcortical nucleus in mammals, essentially composed of excitatory projection neurons and known for its extensive connections with the neocortex, has recently been associated with a variety of functions ranging from consciousness to impulse control. However, research on the CLA has been challenging due to difficulties in specifically and comprehensively targeting its neuronal populations. In various cases, this limitation has led to inconsistent findings and a lack of reliable data. In the present work, we describe the expression profile of the Smim32 gene, which is almost exclusively transcribed in excitatory neurons of the CLA and the endopiriform nucleus, as well as in inhibitory neurons of the thalamic reticular nucleus. Leveraging this unique expression pattern, we developed a series of Cre- and Flippase-expressing knockin and BAC transgenic mouse lines with different expression profiles. With these novel tools in hand, we propose new standards for the interrogation of CLA function.

Mechanical interactions between cells play a fundamental role in the self-organization of organisms. How these interactions drive coordinated cell movement in three dimensions remains unclear. Here we report that cell doublets embedded in a three-dimensional extracellular matrix undergo spontaneous rotations. We investigate the rotation mechanism and find that it is driven by a polarized distribution of myosin within cell cortices. The mismatched orientation of this polarized distribution breaks the doublet mirror symmetry. In addition, cells adhere at their interface through adherens junctions and with the extracellular matrix through focal contacts near myosin clusters. We use a physical theory describing the doublet as two interacting active surfaces to show that rotation is driven by myosin-generated gradients of active tension whose profiles are dictated by interacting cell polarity axes. We also show that three-dimensional shape symmetries are related to broken symmetries of the myosin distribution in cortices. To test for the rotation mechanism, we suppress myosin clusters using laser ablation and generate new myosin clusters by optogenetics. Our work clarifies how polarity-oriented active mechanical forces drive collective cell motion in three dimensions.

 Perioperative management in autologous breast reconstruction has gained focus in recent years. This study compares two pain management protocols in patients undergoing abdominal-based free flap breast reconstruction: a past protocol (PP) and a current protocol (CP)-both intended to reduce opioid consumption postoperatively. The PP entails use of a pain catheter in the abdominal wound and the CP consists of an intraoperative nerve block in addition to refinements in the oral pain management. We hypothesize that the CP reduces opioid consumption compared to PP.  From December 2017 to January 2020, 102 patients underwent breast reconstruction with an abdominal-based free flap. Two postoperative pain management strategies were used during the period; from December 2017 to September 2018, the PP was used which entailed the use of a pain catheter with ropivacaine applied in the abdominal wound with continuous distribution postoperatively in addition to paracetamol orally and oxycodone orally pro re nata (PRN). From October 2018 to January 2020, the CP was used. This protocol included a combination of intraoperative subfascial nerve block and a postoperative oral pain management regime that consisted of paracetamol, celecoxib, and gabapentin as well as oxycodone PRN.  The CP group (  = 63) had lower opioid consumption compared to the PP group (  = 39) when examining all aspects of opioid consumption, including daily opioid usage in morphine milligram equivalents and total opioid usage during the stay (  

The transition from fins to limbs has been a rich source of discussion for more than a century. One open and important issue is understanding how the mechanisms that pattern digits arose during vertebrate evolution. In this context, the analysis of gene expression and functions to infer evolutionary scenarios has been a productive approach to explain the changes in organ formation, particularly in limbs. In tetrapods, the transcription of genes in developing digits depends on a well-characterized set of enhancers forming a large regulatory landscape. This control system has a syntenic counterpart in zebrafish, even though they lack digits, suggestive of deep homology between distal fin and limb developmental mechanisms. We tested the global function of this landscape to assess ancestry and source of limb and fin variation. In contrast to results in mice, we show here that the deletion of the homologous control region in zebrafish has a limited effect on the transcription genes during fin development. However, it fully abrogates expression within the developing cloaca, an ancestral structure related to the mammalian urogenital sinus. We show that similar to the limb, gene function in the urogenital sinus of the mouse also depends on enhancers located in this same genomic domain. Thus, we conclude that the current regulation underlying gene expression in distal limbs was co-opted in tetrapods from a preexisting cloacal program. The orthologous chromatin domain in fishes may illustrate a rudimentary or partial step in this evolutionary co-option.