Biology subjects

Hunt, L.

Publications and source records attributed to Hunt, L..

3 recordsLinked to original sources

bioRxiv2024

Gelatinous fibers develop asymmetrically for posture support of bends and coils in common bean vine

Gelatinous (G)-fibers are common in the stems of twining vines (twiners), but their role remain unclear given the lack of developmental insights. Here, we characterize the developmental anatomy of G-fiber formation in common bean stems (Phaseolus vulgaris L., Fabaceae). G-fibers in common bean exhibit cell wall organization comparable to other species, consisting of cellulose and Rhamnogalacturonan-I pectins, with possible traces of lignin. We show that G-fibers are absent in the actively circumnutating stems, thus these tensile fibers are not associated with the dynamic searching movements characteristics of twiners. Instead, we found that after a subtle bend or dramatic coil is formed, G-fibers form asymmetrically on the concave side of the stem for posture maintenance. Therefore, G-fibers do not drive movement, but provide support for existing bends, thus stabilizing the helical conformation of twiners around its host to avoid slippage. Finally, we present common bean as an emergent system to study twiners and growth form diversity given its easy cultivation, self-pollination, fast growth, and habit diversity arising from plant breeding, and the ability to induce habit shifts through simple modifications to light conditions.

plant biology↗

bioRxiv2019

Inherited duplications of PPP2R3B promote naevi and melanoma via a novel C21orf91-driven proliferative phenotype

The majority of the heredity of melanoma remains unexplained, however inherited copy number changes have not yet been systematically studied. The genetic environment is highly relevant to treatment stratification, and new gene discovery is therefore desirable. Using an unbiased whole genome screening approach for copy number we identify here a novel melanoma predisposing factor, familial duplications of gene PPP2R3B, encoding a regulatory unit of critical phosphatase PP2A. Significant correlation between expression of PPP2R3B in tumour tissue and survival in a large melanoma cohort was confirmed, and associated with a non-immunological expression profile. Mechanistically, construction and extensive characterization of a stable, inducible cellular model for PPP2R3B overexpression revealed induction of pigment cell switching towards proliferation and away from migration. Importantly, this was independent of the known microphthalmia-associated transcription factor (MITF)-controlled pigment cell phenotype switch, and was instead driven by uncharacterised gene C21orf91. Bioinformatic studies point to C21orf91as a novel target of MITF, and therefore a potential hub in the control of phenotype switching in melanoma. This study identifies novel germline copy number variants in PPP2R3B predisposing to melanocytic neoplasia, and uncovers a new potential therapeutic target C21orf91 in the control of pigment cell proliferation.

genomics↗

bioRxiv2018

Differential valuation and learning from social and non-social cues in Borderline Personality Disorder

BackgroundVolatile interpersonal relationships are a core feature of Borderline Personality Disorder (BPD), and lead to devastating disruption of patients personal and professional lives. Quantitative models of social decision making and learning hold promise for defining the underlying mechanisms of this problem. In this study, we tested BPD and control subject weighting of social versus non-social information, and their learning about choices under stable and volatile conditions. We compared behavior using quantitative models.\n\nMethodsSubjects (n=20 BPD, n=23 control) played an extended reward learning task with a partner (confederate) that requires learning about non-social and social cue reward probability (The Social Valuation Task). Task experience was measured using language metrics: explicit emotions/beliefs, talk about the confederate, and implicit distress (using the previously established marker self-referentiality). Subjects weighting of social and non-social cues was tested in mixed-effects regression models. Subjects learning rates under stable and volatile conditions were modelled (Rescorla-Wagner approach) and group x condition interactions tested.\n\nResultsCompared to controls, BPD subject debriefings included more mentions of the confederate and less distress language. BPD subjects also weighted social cues more heavily, but had blunted learning responses to (non-social and social) volatility.\n\nConclusionsThis is the first report of patient behavior in the Social Valuation Task. The results suggest that BPD subjects expect higher volatility than do controls. These findings lay the groundwork for a neuro-computational dissection of social and non-social belief updating in BPD, which holds promise for the development of novel clinical interventions that more directly target pathophysiology.

neuroscience↗