Muséum National d'Histoire Naturelle
  • Paris, Ile de France, France
Recent publications
Sirenians are a well-known example of morphological adaptation to a shallow-water grazing diet characterized by a modified feeding apparatus and orofacial morphology. Such adaptations were accompanied by an anterior tooth reduction associated with the development of keratinized pads, the evolution of which remains elusive. Among sirenians, the recently extinct Steller's sea cow represents a special case for being completely toothless. Here, we used μ-CT scans of sirenian crania to understand how motor-sensor systems associated with tooth innervation responded to innovations such as keratinized pads and continuous dental replacement. In addition, we surveyed nine genes associated with dental reduction for signatures of loss of function. Our results reveal how patterns of innervation changed with modifications of the dental formula, especially continuous replacement in manatees. Both our morphological and genomic data show that dental development was not completely lost in the edentulous Steller's sea cows. By tracing the phylogenetic history of tooth innervation, we illustrate the role of development in promoting the innervation of keratinized pads, similar to the secondary use of dental canals for innervating neomorphic keratinized structures in other tetrapod groups.
Although used for one century in billions of people as the vaccine adjuvant with the best benefit/side-effect balance, aluminium salts/gels have drawbacks of rapid leakage of antigens from the injection site and indefinite persistence. Herein, we propose an alternative to canonical Al-adjuvant. Proteins, nucleic acids, and bacteria were successfully encapsulated within an Al-based Metal-Organic Framework (MOF), namely Al-fumarate, using a synthesis process in water and room temperature, compatible with bio-entities preservation. Mice immunizations demonstrated antigenicity preservation of tetanus toxoid and inactivated E. coli, and a stronger adjuvant effect of Al-fumarate than benchmark Al-adjuvant (Alhydrogel) with an initial slow antigen release and a protective effect. The Al-fumarate vaccine formulation was fully resorbable in vivo, disappearing from the injection site, was not exhibiting any toxicity, and was stable for two years. The limitation of Al adjuvants as eliciting only antibody responses was also overcome by co-immobilisation of CpG 1018 with tetanus toxoid.
We report the first large-scale palaeoproteomics research on eastern and southern African zooarchaeological samples, thereby refining our understanding of early caprine (sheep and goat) pastoralism in Africa. Assessing caprine introductions is a complicated task because of their skeletal similarity to endemic wild bovid species and the sparse and fragmentary state of relevant archaeological remains. Palaeoproteomics has previously proved effective in clarifying species attributions in African zooarchaeological materials, but few comparative protein sequences of wild bovid species have been available. Using newly generated type I collagen sequences for wild species, as well as previously published sequences, we assess species attributions for elements originally identified as caprine or ‘unidentifiable bovid’ from 17 eastern and southern African sites that span seven millennia. We identified over 70% of the archaeological remains and the direct radiocarbon dating of domesticate specimens allows refinement of the chronology of caprine presence in both African regions. These results thus confirm earlier occurrences in eastern Africa and the systematic association of domesticated caprines with wild bovids at all archaeological sites. The combined biomolecular approach highlights repeatability and accuracy of the methods for conclusive contribution in species attribution of archaeological remains in dry African environments.
Natural history museums are vital repositories of specimens, samples and data that inform about the natural world; this Formal Comment revisits a Perspective that advocated for the adoption of compassionate collection practices, querying whether it will ever be possible to completely do away with whole animal specimen collection.
Amino acid-containing macrolactams represent a structurally diverse group of bioactive natural products derived from polyketides; however we are currently lacking a comprehensive overview about their abundance across bacterial families and the underlying biosynthetic diversity. In this study, we employed a targeted β-amino acid-specific homology-based multi-query search to identify potential bacterial macrolactam producers. Here we demonstrate that approximately 10% of each of the identified actinobacterial genera harbor a biosynthetic gene cluster (BGC) encoding macrolactam production. Based on our comparative study, we propose that mutations occurring in specific regions of polyketide synthases (PKS) are the primary drivers behind the variation in macrolactam ring sizes. We successfully validated two producers of ciromicin A from the genus Amycolatopsis , revised the composition of the biosynthetic gene cluster region mte of macrotermycins, and confirmed the ciromicin biosynthetic pathway through heterologous expression. Additionally, network-based metabolomic analysis uncovered three previously unreported macrotermycin congeners from Amycolatopsis sp. M39. The combination of targeted mining and network-based analysis serves as a powerful tool for identifying macrolactam producers and our studies will catalyze the future discovery of yet unreported macrolactams.
Climate change has non‐linear impacts on species distributions and abundance that have cascading effects on ecosystem structure and function. Among them are shifts in trophic interactions within communities. Sites found at the interface between two or more biogeographical regions, where species with diverse thermal preferenda are assembled, are areas of strong interest to study the impact of climate change on communities' interactions. This study examined variation in trophic structure in the Celtic Sea, a temperate environment that hosts a mixture of cold‐affiliated Boreal species and warm‐affiliated Lusitanian species. Using carbon and nitrogen stable isotope ratios, trophic niche area, width, and position were investigated for 10 abundant and commercially important demersal fish species across space and time. In general, the niches of Boreal species appear to be contracting while those of Lusitanian species expand, although there are some fluctuations among species. These results provide evidence that trophic niches can undergo rapid modifications over short time periods (study duration: 2014–2021) and that this process may be conditioned by species thermal preferenda. Boreal species displayed spatial variation in trophic niche width and seem to be facing increased competition with Lusitanian species for food resources. These findings underscore the need to utilize indicators related to species trophic ecology to track the ecosystem alterations induced by climate change. Such indicators could reveal that the vulnerability of temperate ecosystems is currently being underestimated.
Wild potato relatives ( Solanum L. sec. Petota ) play a vital role in crop improvement, in understanding crop evolution, and in conserving potato diversity. However, these invaluable resources are often neglected and underutilized, while susceptible to threats such as climate change, urbanization, and agricultural expansion. Little is known about the diversity, conservation status, and distribution of wild potato species in Colombia. To address this gap, we assessed the conservation status of five wild potato relatives conserved in the ex situ Colombian Central Collection. The five species were analyzed for their spatial patterns of biodiversity, conservation status, and conservation gaps. Colombia was found to have six centers of species richness, four areas of endemism, and six biogeographical regions. Of the five native species, only one was classified as adequately conserved for ex situ conservation, while the other four were considered low priority. In contrast, for in situ conservation, three species showed high priority, one was classified as medium priority, and one as low priority. In light of these findings, we propose three conservation strategies: (1) conducting collection missions to increase accessions in the national germplasm bank, prioritizing high‐priority species, (2) identifying and protecting unprotected natural habitats and engaging stakeholders to enhance in situ conservation efforts, and (3) establishing regional community genebanks to ensure localized conservation efforts. This article is protected by copyright. All rights reserved
Birds are so stable that they can rest and even sleep standing up. We propose that stable static balance is achieved by tensegrity. The rigid bones can be held together by tension in the tendons, allowing the system to stabilize under the action of gravity. We used the proportions of the bird's osteomuscular system to create a mathematical model. First, the extensor muscles and tendons of the leg are replaced by a single cable that follows the leg and is guided by joint pulleys. Analysis of the model shows that it can achieve balance. However, it does not match the biomechanical characteristics of the bird's body and is not stable. We then replaced the single cable with four cables, roughly corresponding to the extensor groups, and added a ligament loop at the knee. The model is then able to reach a stable equilibrium and the biomechanical characteristics are satisfied. Some of the anatomical features used in our model correspond to innovations unique to the avian lineage. We propose that tensegrity, which allows light and stable mechanical systems, is fundamental to the evolution of the avian body plan. It can also be used as an alternative model for bipedal robots.
Studies of material returned from Cb asteroid Ryugu have revealed considerable mineralogical and chemical heterogeneity, stemming primarily from brecciation and aqueous alteration. Isotopic anomalies could have also been affected by delivery of exogenous clasts and aqueous mobilization of soluble elements. Here, we show that isotopic anomalies for mildly soluble Cr are highly variable in Ryugu and CI chondrites, whereas those of Ti are relatively uniform. This variation in Cr isotope ratios is most likely due to physicochemical fractionation between ⁵⁴ Cr-rich presolar nanoparticles and Cr-bearing secondary minerals at the millimeter-scale in the bulk samples, likely due to extensive aqueous alteration in their parent bodies that occurred 5.2 − 1.4 + 1.8 Ma after Solar System birth. In contrast, Ti isotopes were marginally affected by this process. Our results show that isotopic heterogeneities in asteroids are not all nebular or accretionary in nature but can also reflect element redistribution by water.
Objectives Analyses of external bone shape using geometric morphometrics (GM) and cross‐sectional geometry (CSG) are frequently employed to investigate bone structural variation and reconstruct activity in the past. However, the association between these methods has not been thoroughly investigated. Here, we analyze whole bone shape and CSG variation of metacarpals 1–5 and test covariation between them. Materials and Methods We analyzed external metacarpal shape using GM and CSG of the diaphysis at three locations in metacarpals 1–5. The study sample includes three modern human groups: crew from the shipwrecked Mary Rose ( n = 35 metacarpals), a Pre‐industrial group ( n = 50), and a Post‐industrial group ( n = 31). We tested group differences in metacarpal shape and CSG, as well as correlations between these two aspects of metacarpal bone structure. Results GM analysis demonstrated metacarpus external shape variation is predominately related to changes in diaphyseal width and articular surface size. Differences in external shape were found between the non‐pollical metacarpals of the Mary Rose and Pre‐industrial groups and between the third metacarpals of the Pre‐ and Post‐industrial groups. CSG results suggest the Mary Rose and Post‐industrial groups have stronger metacarpals than the Pre‐industrial group. Correlating CSG and external shape showed significant relationships between increasing external robusticity and biomechanical strength across non‐pollical metacarpals ( r : 0.815–0.535; p ≤ 0.05). Discussion Differences in metacarpal cortical structure and external shape between human groups suggest differences in the type and frequency of manual activities. Combining these results with studies of entheses and kinematics of the hand will improve reconstructions of manual behavior in the past.
A genetic duplication event during evolution allowed male wood tiger moths to have either yellow or white patterns on their wings.
Lampreys, one of two living lineages of jawless vertebrates, are always intriguing for their feeding behavior via the toothed suctorial disc and life cycle comprising the ammocoete, metamorphic, and adult stages. However, they left a meager fossil record, and their evolutionary history remains elusive. Here we report two superbly preserved large lampreys from the Middle-Late Jurassic Yanliao Biota of North China and update the interpretations of the evolution of the feeding apparatus, the life cycle, and the historic biogeography of the group. These fossil lampreys’ extensively toothed feeding apparatus differs radically from that of their Paleozoic kin but surprisingly resembles the Southern Hemisphere pouched lamprey, which foreshadows an ancestral flesh-eating habit for modern lampreys. Based on the revised petromyzontiform timetree, we argued that modern lampreys’ three-staged life cycle might not be established until the Jurassic when they evolved enhanced feeding structures, increased body size and encountered more penetrable host groups. Our study also places modern lampreys’ origin in the Southern Hemisphere of the Late Cretaceous, followed by an early Cenozoic anti-tropical disjunction in distribution, hence challenging the conventional wisdom of their biogeographical pattern arising from a post-Cretaceous origin in the Northern Hemisphere or the Pangean fragmentation in the Early Mesozoic.
Excited states and free radicals are involved in the normal physiology of living systems; in pathological processes including lipid peoxidation, inflammation, Parkinson's disease, cancer, and ageing; in the mechanism of action of drugs, such as quinone antitumour agents, and in the photochemotherapies such as the PUVA therapy of skin diseases and PDT of cancer. The chief aim of this text is to introduce the reader to this rapidly expanding field, which lies at the borderlines of physics, chemistry, biology, pharmacology, and medicine, and, in particular, to explore how time-resolved spectroscopic methods have found solutions at the molecular level to biological and medical problems. In the first three chapters, the nature of excited states and free radicals, and the fast kinetic and spectroscopic techniques for their study are described. Amongst the biological areas described in the subsequent chapters are: activated oxygen species; DNA; proteins; carotenoids and photosynthetic reaction centres; photodermatology and melanogenesis; and aspects of cancer related to radio-, chemo-, and photodynamic therapy.
Microorganisms are key contributors of aquatic biogeochemical cycles but their microscale ecology remains largely unexplored, especially interactions occurring between phytoplankton and microorganisms in the phycosphere, that is the region immediately surrounding phytoplankton cells. The current study aimed to provide evidence of the phycosphere taking advantage of a unique hypersaline, hyperalkaline ecosystem, Lake Dziani Dzaha (Mayotte), where two phytoplanktonic species permanently co‐dominate: a cyanobacterium, Arthrospira fusiformis , and a green microalga, Picocystis salinarum. To assay phycospheric microbial diversity from in situ sampling, we set up a flow cytometry cell‐sorting methodology for both phytoplanktonic populations, coupled with metabarcoding and comparative microbiome diversity. We focused on archaeal communities as they represent a non‐negligible part of the phycospheric diversity, however their role is poorly understood. This work is the first which successfully explores in situ archaeal diversity distribution showing contrasted phycospheric compositions, with P. salinarum phycosphere notably enriched in Woesearchaeales OTUs while A. fusiformis phycosphere was enriched in methanogenic lineages affiliated OTUs such as Methanomicrobiales or Methanofastidiosales. Most archaeal OTUs, including Woesearchaeales considered in literature as symbionts, were either ubiquitous or specific of the free‐living microbiome (i.e. present in the 3–0.2 μm fraction). Seminally, several archaeal OTUs were enriched from the free‐living microbiome to the phytoplankton phycospheres, suggesting (i) either the inhibition or decrease of other OTUs, or (ii) the selection of specific OTUs resulting from the physical influence of phytoplanktonic species on surrounding Archaea.
Adulis, located on the Red Sea coast in present-day Eritrea, was a bustling trading centre between the first and seventh centuries CE. Several classical geographers--Agatharchides of Cnidus, Pliny the Elder, Strabo-noted the value of Adulis to Greco--Roman Egypt, particularly as an emporium for living animals, including baboons ( Papio spp.). Though fragmentary, these accounts predict the Adulite origins of mummified baboons in Ptolemaic catacombs, while inviting questions on the geoprovenance of older (Late Period) baboons recovered from Gabbanat el-Qurud ('Valley of the Monkeys'), Egypt. Dated to ca. 800-540 BCE, these animals could extend the antiquity of Egyptian-Adulite trade by as much as five centuries. Previously, Dominy et al. (2020) used stable istope analysis to show that two New Kingdom specimens of P. hamadryas originate from the Horn of Africa. Here, we report the complete mitochondrial genomes from a mummified baboon from Gabbanat el-Qurud and 14 museum specimens with known provenance together with published georeferenced mitochondrial sequence data. Phylogenetic assignment connects the mummified baboon to modern populations of Papio hamadryas in Eritrea, Ethiopia, and eastern Sudan. This result, assuming geographical stability of phylogenetic clades, corroborates Greco-Roman historiographies by pointing toward present-day Eritrea, and by extension Adulis, as a source of baboons for Late Period Egyptians. It also establishes geographic continuity with baboons from the fabled Land of Punt (Dominy et al., 2020), giving weight to speculation that Punt and Adulis were essentially the same trading centres separated by a thousand years of history.
Seed germination is a major determinant of plant development and final yield establishment but strongly reliant on the plant's abiotic and biotic environment. In the context of global climate change, classical approaches to improve seed germination under challenging environments through selection and use of synthetic pesticides reached their limits. A currently underexplored way is to exploit the beneficial impact of the microorganisms associated with plants. Among plant microbiota, endophytes, which are microorganisms living inside host plant tissues without causing any visible symptoms, are promising candidates for improving plant fitness. They possibly establish a mutualistic relationship with their host, leading to enhanced plant yield and improved tolerance to abiotic threats and pathogen attacks. The current view is that such beneficial association relies on chemical mediations using the large variety of molecules produced by endophytes. In contrast to leaf and root endophytes, seed-borne fungal endophytes have been poorly studied although they constitute the early-life plant microbiota. Moreover, seed-borne fungal microbiota and its metabolites appear as a pertinent lever for seed quality improvement. This review summarizes the recent advances in the identification of seed fungal endophytes and metabolites and their benefits for seed biology, especially under stress. It also addresses the mechanisms underlying fungal effects on seed physiology and their potential use to improve crop seed performance.'
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1,476 members
Barbara Demeneix
  • UMR 7221, Dept RDDM
Arnaud Catherine
  • Département Régulations, développement et diversité moléculaire
Chakib Djediat
  • Département Régulations, développement et diversité moléculaire
57, rue Cuvier, 75005, Paris, Ile de France, France
Head of institution
Bruno David, PDG