Biology subjects

Charles, F.

Publications and source records attributed to Charles, F..

4 recordsLinked to original sources

bioRxiv2025

Rapid Derivation of Cloning-Competent Cells from Peripheral Blood Advances Conservation Biobanking

I.Establishing viable cell lines from endangered species is essential for conservation, yet traditional fibroblast derivation from skin biopsies faces challenges including variable success rates, contamination risk, and extended culture timelines. We demonstrate that endothelial progenitor cells (EPCs) and pericytes isolated from peripheral blood represent superior alternatives for biobanking across three mammalian genera (Canis, Bison, and Equus). Blood-derived cells exhibited 2-3 fold faster doubling rates (15-20 hours versus >35 hours for fibroblasts) and reduced time to generate banked lines from 3-4 weeks to 1.5-2 weeks. Proteomic profiling of 32 canonical markers confirmed EPCs and pericytes represent distinct populations with lineage-specific molecular signatures. Optical genome mapping demonstrated equivalent genomic stability across all cell types with no detectable structural variants or aneuploidies. Critically, interspecific somatic cell nuclear transfer (iSCNT) experiments confirmed both EPCs and pericytes generate viable embryos with efficiency meeting or exceeding fibroblasts. Gray wolf blood-derived cells produced six viable fetuses with 15% implantation rate, while bison EPCs showed higher blastocyst formation (7%) than fibroblasts (3%) from the same individual. Blood collection during routine veterinary procedures offers minimally invasive sampling with reduced contamination compared to skin biopsies. These findings support integrating blood-derived cell banking into conservation programs, enabling opportunistic genetic preservation during standard management activities and expanding options for genetic rescue through assisted reproductive technologies.

cell biology↗

bioRxiv2025

VISTA-induced tumor suppression by a four amino acid intracellular motif

VISTA is a key immune checkpoint receptor under investigation for cancer immunotherapy; however, its signaling mechanisms remain unclear. Here we identify a conserved four amino acid (NPGF) intracellular motif in VISTA that suppresses cell proliferation by constraining cell-intrinsic growth receptor signaling. The NPGF motif binds to the adapter protein NUMB and recruits Rab11 endosomal recycling machinery. We identify and characterize a class of triple-negative breast cancers with high VISTA expression and low proliferative index. In tumor cells with high VISTA levels, the NPGF motif sequesters NUMB at endosomes, which interferes with epidermal growth factor receptor (EGFR) trafficking and signaling to suppress tumor growth. These effects do not require canonical VISTA ligands, nor a functioning immune system. As a consequence of VISTA expression, EGFR receptor remains abnormally phosphorylated and cannot propagate ligand-induced signaling. Mutation of the VISTA NPGF domain reverts VISTA-induced growth suppression in multiple breast cancer mouse models. These results define a mechanism by which VISTA represses NUMB to control malignant epithelial cell growth and signaling. They also define distinct intracellular residues that are critical for VISTA-induced cell-intrinsic signaling that could be exploited to improve immunotherapy.

cancer biology↗

bioRxiv2023

Photosynthesis is led by stomatal circadian rhythm and not by starch depletion after a long period of darkness

The circadian rhythm is an endogenous rhythm, defined by repeated metabolic oscillations every 24 hours under constant parameters. In plants, the circadian rhythm regulates the growth through photosynthesis and the management of carbohydrates. In indoor farming, the photoperiod is independent from the sunlight and is of interest to increase energy savings. In this work, we studied the effects of modifications of photoperiods on indoor-grown lettuces (L. sativa), which were then not tuned with the circadian rhythm. The pattern of photoperiods applied was: 16/12-16/8-16/8. A mutant-free study was carried out to avoid genes shutdown unintended side effects and to evaluate the impact of the circadian rhythm under marketable production conditions. We observed that the circadian regulation of the stomatal conductance was the main limiting factor of net photosynthesis when the photoperiod is exceptionally not tuned with the circadian rhythm. In our experiment, the disruption of the circadian rhythm decreased the photosynthetic activity by 6.2% throughout the light period, with no alteration of the yield, morphology or light and water use efficiencies. Furthermore, starch depletion induced by the changes in the photoperiod could not explain variations of the net photosynthetic activity during the following light period. Interestingly, disrupting the circadian rhythm saved 5% of lighting time compared to the control, which can be converted into energy savings. Consequently, the circadian rhythm can be defined as a limiting factor for reducing energy consumption in indoor farming. Further characterization of the links between the photosynthesis-carbohydrates-growth continuum and the circadian rhythm is thus required.

plant biology↗

bioRxiv2017

Estimating Muricid abundances from trapping methods used in Mediterranean Tyrian Purple industry

A new statistical method based on a stochastic dynamic model is proposed to assess population abundances of murcid species at scales relevant to both Ancient and Modern artisanal, coastal fisheries. Motivated by the long-term goal of reconstructing the dynamics of exploited murex populations during Antiquity, the objective was to quantify the population density of the banded-dye murex, Hexaplex trunculus (Linnaeus, 1758) from successive captures with baited traps, using a method similar to the technique employed in the Mediterranean purple dye industry. A stochastic model simulating cumulative captures while taking into account high variability was developed and calibrated with data acquired during a field experiment conducted on Crete Island, near Heraklion. Sampling devices were deployed in two shallow water habitats. The traps catchability and the Effective Area of Attraction were estimated using the individual speed and behavioural response toward the bait observed during independent laboratory experiments. The average density of H. trunculus was estimated at 2.2 {+/-} 1.4 SE individuals per square meter, with no significant differences between seagrass and rocky habitats, respectively. The clearing time (the time to catch all individuals within reach of the trap) of the successive experiments was 84 {+/-} 6 SE hours, on average. This means that clearing ca. 0.4 ha of subtidal area would be necessary to produce ca. 1.0 g of pure dye pigment. While the method is discussed here with respect to a particular historical context, it is generalizable to making population abundance estimates for other species such as whelks, in modern fisheries.

ecology↗