Biology subjects

Mead, T.

Publications and source records attributed to Mead, T..

3 recordsLinked to original sources

bioRxiv2025

Which plant traits increase soil carbon sequestration? Empirical evidence from a long-term poplar genetic diversity trial

Breeding or engineering crops to increase soil organic carbon (SOC) storage is a potential route to land-based carbon dioxide removal on working agricultural lands. However, due to limited observational datasets plus shifting paradigms of SOC stabilization, there is a lack of understanding of which plant traits to target for SOC enhancement or the ultimate sequestration potential of such measures. Existing long-term common gardens of genetically diverse plant populations may provide an opportunity to evaluate biological controls on SOC outcomes, separate from environmental or management variability. Here we report on soil carbon and root chemical data collected for 24 genotypes within a 13-year-old common garden in northwestern Oregon planted with over a thousand natural variants of Populus trichocarpa. Fractionating surface soil (0-15 cm) revealed substantial variation in stocks of mineral-associated organic matter (MAOM; 18-67 tonnes C/ha) and particulate organic matter (POM; 2-22 tonnes C/ha). Tree genotype explained 24 and 26% of the MAOM and POM stock variability, respectively, after controlling for background variability. We found minimal association between SOC concentration and either aboveground tree productivity or conventional metrics of root biomass recalcitrance (C/N ratios and lignin content). However, root elemental content appeared influential for MAOM-C, which showed a strong positive association with root aluminum (Al), and strong negative association with root boron (B) and magnesium (Mg). Furthermore, root concentrations of these elements were highly heritable (57-78%) and not simply a reflection of background variation in bulk soil elemental concentrations. We estimate that surface SOC stocks under these 24 genotypes have diverged at rates of up to 1.2-4.3 tonnes C/ha/yr. These results suggest that genetic diversity trials have value for elucidating biological controls on SOC dynamics, and that traits associated with root elemental content may be an important target for enhancing SOC.

ecology↗

bioRxiv2020

Active Perception during Angiogenesis: Filopodia speed up Notch selection of tip cells in silico and in vivo

How do cells make efficient collective decisions during tissue morphogenesis? Humans and other organisms utilize feedback between movement and sensing known as sensorimotor coordination or active perception to inform behaviour, but active perception has not before been investigated at a cellular level within organs. Here we provide the first proof of concept in silico/in vivo study demonstrating that filopodia (actin-rich, dynamic, finger like cell-membrane protrusions) play an unexpected role in speeding up collective endothelial decisions during the time-constrained process of tip cell selection during blood vessel formation (angiogenesis). We first validate simulation predictions in vivo with live imaging of zebrafish intersegmental vessel growth. Further simulation studies then indicate the effect is due to the coupled positive feedback between movement and sensing on filopodia conferring a bistable switch-like property to Notch lateral inhibition, ensuring tip selection is a rapid and robust process. We then employ measures from computational neuroscience to assess whether filopodia function as a primitive ( basal) form of active perception and find evidence in support. By viewing cell behaviour in tissues through the basal cognitive lens we acquire a fresh perspective on not only the well-studied tip cell selection process, revealing a hidden, yet vital, time-keeping role for filopodia, but on how to interpret and understand cell behaviour in general, opening up a myriad of new and exciting research directions.

cell biology↗

bioRxiv2019

Mouse retinal cell behaviour in space and time using light sheet fluorescence microscopy

As the general population ages and the incidence of diabetes increases epidemically, more people are affected by eye diseases, such as retinopathies. It is therefore critical to improve imaging of eye disease mouse models. Here, we demonstrate that 1) rapid, quantitative 3D and 4D (time lapse) imaging of cellular and subcellular processes in the murine eye is feasible, with and without tissue clearing, using light-sheet fluorescent microscopy (LSFM) and 2) LSFM readily reveals new features of even well studied eye disease mouse models, such as the Oxygen-Induced Retinopathy (OIR) model. Through correlative LSFM-Confocal imaging we find that flat-mounting retinas for confocal microscopy significantly distorts tissue morphology. The minimized distortion with LSFM dramatically improved analysis of pathological vascular tufts in the OIR model revealing \"knotted\" morphologies, leading to a proposed new tuft nomenclature. Furthermore, live-imaging of OIR tuft formation revealed abnormal cell motility and altered filopodia dynamics. We conclude that quantitative 3D/4D LSFM imaging and analysis has the potential to advance our understanding of pathological processes in the eye, in particular neuro-vascular degenerative processes.

developmental biology↗