Publications

The western honeybee, harbours a simple and distinct microbiota that has been linked to various positive outcomes for the host. Among these cited benefits is improved weight gain for bees that have been inoculated with their native microbes. This result has been challenged by recent studies which investigated the impact of the gut microbiota on behavioural maturation and associated physiological changes and revealed no effect of the gut microbiota on weight gain. Therefore, we re-examined the role of the microbiota in weight gain by comparing microbiota-deprived bees with those inoculated with gut homogenate or defined communities composed of isolates representing the major bacterial taxa inhabiting the bee gut. We observed no differences in weight gain of adult bees or of their gut tissues across these groups. Further analysis based on nurse/forager cuticular hydrocarbon status and bacterial composition also revealed no significant changes. These results suggest the need for more nuanced investigations aimed at exploring factors such as the conditions in the hive of origin, including larval nutrition.

Foraminifera are highly diverse rhizarian protists, with some lineages having developed the ability to retain chloroplasts from algal prey (kleptoplasty). Recently, we revealed the evolutionary relationship between kleptoplasty and algal symbiosis in the benthic foraminifera . In this study, we explored fundamental aspects of host-kleptoplast interactions. The photosynthetic rates of show the sequestered kleptoplast activity under a wide range of light intensities with no signs of photoinhibition. This lack of photoinhibition response may be attributed to the loss of key elements responsible for this process during the acquisition of kleptoplasts. Our study demonstrates the stability and notably extended retention of kleptoplasty in , evidenced by its plastid retention under conditions of heterotrophic feeding deprivation for 50 days. The host-kleptoplast interactions suggest that is highly committed to this partnership and that this kleptoplasty species likely relies on similar kleptoplast/alga maintenance mechanisms as symbiont-bearing foraminifera.

The morphological intricacies of avian feathers make them an ideal model for investigating embryonic patterning and morphogenesis. In particular, the sonic hedgehog (Shh) pathway is an important mediator of feather outgrowth and branching. However, functional in vivo evidence regarding its role during feather development remains limited. Here, we demonstrate that an intravenous injection of sonidegib, a potent Shh pathway inhibitor, at embryonic day 9 (E9) temporarily produces striped domains (instead of spots) of Shh expression in the skin, arrests morphogenesis, and results in unbranched and non-invaginated feather buds-akin to proto-feathers-in embryos until E14. Although feather morphogenesis partially recovers, hatched treated chickens exhibit naked skin regions with perturbed follicles. Remarkably, these follicles are subsequently reactivated by seven weeks post-hatching. Our RNA-sequencing data and rescue experiment using Shh-agonism confirm that sonidegib specifically down-regulates Shh pathway activity. Overall, we provide functional evidence for the role of the Shh pathway in mediating feather morphogenesis and confirm its role in the evolutionary emergence and diversification of feathers.

Foraminifera are highly diverse rhizarian protists, with some lineages having developed the ability to retain chloroplasts from algal prey (kleptoplasty). Recently, we revealed the evolutionary relationship between kleptoplasty and algal symbiosis in the benthic foraminifera Hauerina diversa. In this study, we explored fundamental aspects of host-kleptoplast interactions. The photosynthetic rates of H. diversa show the sequestered kleptoplast activity under a wide range of light intensities with no signs of photoinhibition. This lack of photoinhibition response may be attributed to the loss of key elements responsible for this process during the acquisition of kleptoplasts. Our study demonstrates the stability and notably extended retention of kleptoplasty in H. diversa, evidenced by its plastid retention under conditions of heterotrophic feeding deprivation for 50 days. The host-kleptoplast interactions suggest that H. diversa is highly committed to this partnership and that this kleptoplasty species likely relies on similar kleptoplast/alga maintenance mechanisms as symbiont-bearing foraminifera.

BackgroundExtent of resection (EOR), including gross total resection (GTR), is one of the most important factors in predicting overall survival (OS) in IDH-wild type (IDH-WT) glioblastoma patients. Although GTR represents the complete resection of all visible contrast-enhancing parts of the tumor, imaging predictors of achieving this extent still need to be better understood.PurposeTo assess the impact of preoperative imaging phenotypes as defined by the VASARI feature set and tumoral volumetry to determine predictors of GTR in patients with IDH-WT glioblastoma.Material and MethodsThis retrospective, single-center study analyzed imaging characteristics based on the VASARI features in the preoperative scans of IDH-WT glioblastoma patients. Volumetric analysis was performed to determine associations with clinical outcomes. Univariate analysis was used to determine the association of VASARI features with GTR. A multivariate analysis model was used to determine predictors of GTR.ResultsGTR was achieved in 79/144 (54.8%) patients, near total resection in 15 (10.4%), and subtotal resection in 50 (34.7%) patients. Our results showed non-eloquent tumor regions (55% vs. 35%; = 0.04) and thick margin of enhancement (56.1% vs. 43.9%; = 0.04) were associated with GTR and ependymal extension (37% vs. 63%; = 0.02). Deep white matter invasion (36.3% vs. 63.7%; = 0.03) was significantly associated with non-gross total resection. Lower tumoral volumes were also associated with gross total resection (

Xenophyophores are an abundant component of the megafauna in parts of the equatorial and temperate North Pacific, but few records exist of these giant agglutinated foraminifera in northern North Pacific and adjacent waters. Here, we present a preliminary survey of xenophyophores from the bathyal Bering Sea (∼3500 m depth) and at abyssal depths (4294–6555 m) adjacent to the Aleutian Trench, based on collected material, mainly fragments, and seafloor images. The dominant xenophyophore in the Bering Sea is a reticulated form that yielded DNA sequences identical to those obtained from Syringammina limosa, a species described from > 2700 km to the west in the Sea of Okhotsk. Also visible in seafloor photographs were various plate-like forms, often with upturned, undulating rims, but also branching plates and other more complicated morphotypes that probably represent distinct species. At stations close to the Aleutian Trench, core and epibenthic sledge samples yielded xenophyophores at seven of the 16 sampling sites. At least eleven morphospecies were recognised among those collected, none of which resembled S. limosa or the plate-like Bering Sea forms. Seafloor images revealed 16 fairly distinct domed or plate-like morphotypes three of these are possibly represented among the collected specimens, making a total of around 24 morphotypes or morphospecies. A few images show morphotypes similar to those seen in the Bering Sea. Our results suggests that xenophyophores are as diverse in the northern North Pacific as they are elsewhere in the Pacific Ocean.

Calcifying foraminifera from the orders Rotaliida and Miliolida are widely used as geochemical proxies for recording paleoceanographic conditions, while agglutinated foraminifera are often overlooked since their tests are mostly composed of foreign particles. This study investigated the geochemical properties of a cosmopolitan agglutinated benthic species from the order Textulariida which has an exceptional inner calcareous test and is evolutionarily basal to Rotaliida. This study confirms the evolutionary link between textulariids and rotaliids based on their geochemistry and establishes as a geochemical recorder of marine environments. Specimens from the Mediterranean coast of Israel were analyzed using laser ablation ICP-MS and compared to whole-test ICP-MS measurements of rotaliid and miliolid taxa from the same location. An Mg/Ca temperature calibration was established by LA-ICP-MS analyses of cultured specimens at 15, 17, 20, and 25 °C. Results show that is a mid-Mg species (~19 to ~60 mmol/mol), with an Mg/Ca temperature correlation similar to high-Mg species. Its Pb, Zn, and Mn/Ca ratios are variable, generally overlapping with rotaliids and significantly lower than miliolids. Notably, exhibits significantly higher Sr/Ca ratios (3.2 to 4.7 mmol/mol) compared to most foraminifera. Raman analyses reveal that the inner wall comprises a mix of aragonite and calcite, explaining these elevated Sr/Ca ratios. Rotaliida are the most prolific group of calcifying foraminifera. Our findings suggest that rotaliid tests evolved from an agglutinated textulariid ancestor with an inner aragonitic wall, a hypothesis that is further supported by the close phylogenetic relationship of the two groups.

African populations remain underrepresented in studies of human genetic diversity, despite a growing interest in understanding how they have adapted to the diverse environments they live in. In particular, understanding the genetic basis of immune adaptation to pathogens is of paramount importance in a continent such as Africa, where the burden of infectious diseases is a major public health challenge. In this study, we investigated the molecular variation of four Human Leukocyte Antigens () class II genes (, , and ), directly involved in the immune response to parasitic infections, in more than 1000 individuals from 23 populations across North, East, Central and West Africa. By analyzing the molecular diversity of these populations in relation to various geographical, cultural and environmental factors, we identified divergent genetic profiles for several (semi-)nomadic populations of the Sahel belt as a signature of their unique demography. In addition, we observed significant genetic structuring supporting both substantial geographic and linguistic differentiations within West Africa. Furthermore, neutrality tests suggest balancing selection has been shaping the diversity of these four class II genes, which is consistent with molecular comparisons between genes and their orthologs in chimpanzees (). However, the most striking observation comes from linear modeling, demonstrating that the prevalence of , the primary pathogen of malaria in Africa, significantly explains a large proportion of the nucleotide diversity observed at the gene. , a highly frequent allele in Burkinabé populations, is identified as a potential protective allele against malaria, suggesting that strong pathogen-driven positive selection at this gene has shaped variation in Africa. Additionally, two low-frequency alleles, and also show significant associations with prevalence, supporting resistance to malaria is determined by multigenic and/or multiallelic combinations rather than single allele effects.

African populations remain underrepresented in studies of human genetic diversity, despite a growing interest in understanding how they have adapted to the diverse environments they live in. In particular, understanding the genetic basis of immune adaptation to pathogens is of paramount importance in a continent such as Africa, where the burden of infectious diseases is a major public health challenge. In this study, we investigated the molecular variation of four Human Leukocyte Antigens (HLA) class II genes (DRB1, DQA1, DQB1 and DPB1), directly involved in the immune response to parasitic infections, in more than 1000 individuals from 23 populations across North, East, Central and West Africa. By analyzing the HLA molecular diversity of these populations in relation to various geographical, cultural and environmental factors, we identified divergent genetic profiles for several (semi-)nomadic populations of the Sahel belt as a signature of their unique demography. In addition, we observed significant genetic structuring supporting both substantial geographic and linguistic differentiations within West Africa. Furthermore, neutrality tests suggest balancing selection has been shaping the diversity of these four HLA class II genes, which is consistent with molecular comparisons between HLA genes and their orthologs in chimpanzees (Patr). However, the most striking observation comes from linear modeling, demonstrating that the prevalence of Plasmodium falciparum, the primary pathogen of malaria in Africa, significantly explains a large proportion of the nucleotide diversity observed at the DPB1 gene. DPB1*01:01, a highly frequent allele in Burkinabé populations, is identified as a potential protective allele against malaria, suggesting that strong pathogen-driven positive selection at this gene has shaped HLA variation in Africa. Additionally, two low-frequency DRB1 alleles, DRB1*08:06 and DRB1*11:02, also show significant associations with P. falciparum prevalence, supporting resistance to malaria is determined by multigenic and/or multiallelic combinations rather than single allele effects.

We present a generic framework for describing interacting, spinning, active polar particles, aimed at modeling dense cell aggregates, where cells are treated as polar, rotating objects that interact mechanically with one another and their surrounding environment. Using principles from nonequilibrium thermodynamics, we derive constitutive equations for interaction forces, torques, and polarity dynamics. We subsequently use this framework to analyze the spontaneous motion of cell doublets, uncovering a rich phase diagram of collective behaviors, including steady rotation driven by flow-polarity coupling or interactions between polarity and cell position.