Biology subjects

Hansson, E. M.

Publications and source records attributed to Hansson, E. M..

5 recordsLinked to original sources

bioRxiv2025

Metabolomic profiling of glyphosate resistance evolution in green alga Chlamydomonas reinhardtii

The widespread use of glyphosate has led to a rapid increase in glyphosate resistant weeds at a considerable cost to agriculture. Furthermore, agricultural run-off means non-target, natural ecosystems are also affected. Resistance may arise both through mutations to target enzyme EPSPS in the shikimate pathway generating insensitivity to glyphosate and through non-target site mutations regulating the dose of glyphosate reaching the shikimate pathway. Either mechanism may trade-off against normal cell functioning. Here, using experimental evolution of replicated Chlamydomonas reinhardtii populations facing glyphosate, we reveal the metabolomic fingerprint of both glyphosate action and emerging resistance by applying untargeted metabolomic screens throughout the course of resistance evolution. Furthermore, this allows us to evaluate potential underlying molecular mechanisms and fitness costs. We find evidence of build-up of shikimate pathway metabolites, a characteristic signal of glyphosate action, that subsides but does not disappear as resistance evolves, suggesting a fitness trade-off. Concurrent with this is evidence of cell wide disruption of the amino acid pool, that stabilises as resistance evolves. We also found evidence of effects of glyphosate on membrane lipids and increased levels of reactive oxygen species persisting after resistance had evolved. This suggests a considerable effect of the recently described secondary effect of glyphosate: oxidative damage. These data highlight several metabolic processes disrupted by and persisting with the evolution of resistance to glyphosate and may provide a template for enhancing predictions of population and ecosystem effects.

evolutionary biology↗

bioRxiv2025

A comprehensive molecular atlas of the cell types in the mouse liver

The liver plays a crucial role in essential physiological processes, and its impaired function due to liver fibrosis from various causes is an increasingly significant health issue. The livers functionality relies on the precise arrangement of its cellular structures, yet the molecular architecture of these units remains only partially understood. We created a comprehensive molecular atlas detailing all the major cell types present in the adult mouse liver through deep single-cell RNA sequencing. Our analysis offers new insights into hepatic endothelial and mesenchymal cells, specifically highlighting the differences between the cells of the periportal microvasculature, the sinusoids, and the portal vein, the latter exhibiting a mixed arterio-venous phenotype. We identified distinct subpopulations of hepatic stellate cells, fibroblasts, and vascular mural cells located in different anatomical regions. Comparisons with transcriptomic data from disease models indicate that a previously unrecognized capsular population of hepatic stellate cells expands in response to fibrotic disease. Our findings reveal that various fibroblast subpopulations respond differently to pathological insults. This data resource will be invaluable for advancing therapeutic interventions targeting hepatic diseases.

cell biology↗

bioRxiv2024

Glyphosate resistance evolution to lethal and sublethal doses in chemostat populations of model organism Chlamydomonas reinhardtii

Herbicide resistant weeds are an increasing economic and ecological problem world-wide. Evolutionary theory and insight from experiments testing this theory are now a central part of solving resistance problems. More specifically, experimental evolution, where populations are allowed to evolve under specific conditions, can offer substantial insights into the trade-offs that govern the pace at which resistance arises. Here we leverage the green alga Chlamydomonas reinhardtii facing glyphosate as a model plant system to evaluate such theory, monitoring the level of evolved resistance and associated fitness costs throughout the course of adaptation. On a gradient of lethal and sub-lethal doses of glyphosate, we found evidence for evolved resistance from standing genetic variation but limited evidence for classic growth rate trade-offs that are expected to affect the pace of resistance evolution.

evolutionary biology↗

bioRxiv2024

Evidence for a trade-off between glyphosate resistance and anti-grazer defence in green alga Chlamydomonas reinhardtii

O_LIThe widespread and persistent use of herbicides has both selected for dramatically increased levels of herbicide resistance in the weed populations they were designed to control, and increased contamination of non-target ecosystems. C_LIO_LIExperimental evolution using microbes offers the opportunity to explore basic evolutionary theory, including testing for the existence of intrinsic and extrinsic fitness trade-offs, connecting them to the patterns observed in both natural and agricultural populations. C_LIO_LIWe used green alga Chlamydomonas reinhardtii adapted to high and moderate levels of glyphosate to test for an extrinsic cost to glyphosate resistance in the form of a trade-off with clumping, the inducible anti-grazer defence deployed against gape-limited micrograzers. Through exposing the algae to freshwater rotifer Brachionus calyciflorus as well as their isolated info-chemicals, we test whether glyphosate resistance affects ability to deploy defences as well as ability to withstand grazing compared to control populations. C_LIO_LIWe find an increase in variation rather than uni-directional effect of glyphosate treatment, with treated populations exhibiting both lower and higher degree of anti-grazer defence compared to controls. Furthermore, our data suggests there are at least three different glyphosate resistant phenotypes present, with two conferring different extrinsic costs in the form of tradeoff with anti-grazer defence. C_LIO_LIOur study indicates that extrinsic costs to glyphosate resistance may be context dependent in this system, possibly only being present at particular stages in the adaptation process or with particular resistance mechanisms. C_LI

ecology↗

bioRxiv2022

Mesostats - A multiplexed, low-cost, do-it-yourself continuous culturing system for experimental evolution of mesocosms

Microbial experimental evolution allows studying evolutionary dynamics in action and testing theory predictions in the lab. Experimental evolution in chemostats (i.e. continuous flow through cultures) has recently gained increased interest as it allows tighter control of selective pressures compared to static batch cultures, with a growing number of efforts to develop systems that are easier and cheaper to construct. This protocol describes the design and construction of a multiplexed chemostat array (dubbed "mesostats") designed for cultivation of algae in 16 concurrent populations, specifically intended for studying adaptation to herbicides. We also present control data from several experiments run on the system to show replicability, data illustrating the effects of common issues like leaks, contamination and clumps, and outline possible modifications and adaptations of the system for future research.

evolutionary biology↗