Biology subjects

Doonan, J.

Publications and source records attributed to Doonan, J..

4 recordsLinked to original sources

bioRxiv2026

Demographic history shapes forest tree vulnerability to climate change

Demographic history is expected to play a central role in shaping population vulnerability to climate change through its lasting effects on effective population sizes and genetic connectivity. However, existing studies report contrasting outcomes, and the consequences of alternative demographic histories have seldom been assessed concurrently across multiple taxa. Here, we analysed population genomic data from six of the major European forest tree species to address this gap. Across species, genetic isolation reduced adaptive potential, as reflected in lower standing genetic diversity. Greater genetic differentiation was also associated with increased maladaptation to climate, whereas the purge or accumulation of deleterious mutations depended on the severity of past demographic events. Finally, the beneficial effects of gene flow were evidenced across the six species by more optimal climate adaptation in highly connected populations. Altogether, our results provide valuable insights into how genetic differentiation, reflecting the combined effects of genetic drift and limited historical gene flow, influences current vulnerability of forest tree populations to climate change.

evolutionary biology↗

bioRxiv2023

Metabolomic approaches highlight two mechanisms of accelerated grain filling in Mediterranean oat (Avena sativa L.) cultivars during drought.

Grain filling in cereals is complex process that determines the final grain yield and quality. Abiotic stresses can have major impact on grain filling. Oats (Avena sativa L.) is sensitive to drought which adversely affect yield and productivity. In this study, we characterised the grain filling responses of two Mediterranean oat cultivars Flega and Patones under severe drought. Grains from the top (older) and bottom (younger) spikelets of primary panicle were larger in size in response to drought, particularly in Patones, suggesting accelerated grain development. The metabolomes of source (sheath, flag leaf) and sink (developing grains) tissues were profiled to describe source-sink partitioning. In Patones, the developing grains showed increased sugars and amino acids which indicate accelerated grain filling. These were associated with elevated -linolenic acid levels in source tissues but decreased in developing grains under drought. There was also a significant decrease in C18 fatty acids (FA) and jasmonates (JA) derivatives in the developing grains which suggested a role for JA signalling in Patones with drought. Flega showed a different response, with accelerated flowering and enhanced energy metabolism in both source and sink organs. The accumulation of ophthalmic acid in grains of Flega and lower levels of reduced glutathione in source tissues suggested greater oxidative stress than Patones under drought may be driving the grain filling phenotype. This study suggests that oats cultivars can use -linolenic acid-linked signalling or oxidative events influences accelerated grain filling with drought. These could be important traits in developing oat cultivars that maintain yield in drought-prone environments. HighlightThe impact on drought in one tolerant and one susceptible oat cultivar was assessed at the grain filling stage. The drought tolerant cultivar, Patones, showed accelerated grain development which could be a strategy to escape drought. Metabolite mapping of flag leaves, sheath and grains of Flega suggested that alpha linolenic acid could be regulating the altered sink-source relationships. The drought susceptible cultivar, Metabolomics shifts in Flega suggested that oxidative stress accelerated flowering.

plant biology↗

bioRxiv2019

Parasitic worm product ES-62 promotes healthspan and lifespan in a mouse model of obesity-induced ageing

The recent extension of human lifespan has not been matched by equivalent improvements in late-life health due to the global pandemic in type-2 diabetes, obesity and cardiovascular disease, ageing-associated conditions exacerbated by widespread adoption of the high calorie Western diet (HCD). As a novel therapeutic strategy, we have investigated the potential of ES-62, an immunomodulator secreted by the parasitic worm Acanthocheilonema viteae, to improve healthspan by targeting the chronic inflammation that drives metabolic dysregulation underpinning ageing-induced ill-health. We found that ES-62 improves a range of inflammatory but also pathophysiological, metabolic and microbiome parameters, when administered subcutaneously at only 1 {micro}g/week throughout the lifespan of HCD-fed mice. Strikingly, ES-62 induced sex-specific healthspan signatures and indeed, it substantially increased the median survival of male, but not female, HCD-mice. Modelling of 113 responses contributing to these differential signatures by machine learning approaches now signposts candidate parameters key to promoting both healthspan and lifespan.

immunology↗

bioRxiv2018

The parasitic worm product ES-62 normalises the gut microbiota/bone marrow axis in inflammatory arthritis

The human immune system has evolved in the context of our colonisation by bacteria, viruses, fungi and parasitic helminths. Reflecting this, the rapid eradication of pathogens appears to have resulted in reduced microbiome diversity and generation of chronically activated immune systems, presaging the recent rise of allergic, autoimmune and metabolic disorders. Certainly, gastrointestinal helminths can protect against gut and lung mucosa inflammatory conditions by modulating the microbiome and suppressing the chronic inflammation associated with dysbiosis. Here, we employ ES-62, an immunomodulator secreted by tissue-dwelling Acanthocheilonema viteae to show that modulation of the gut microbiome does not require live infection with gastrointestinal-based helminths nor is protection restricted to mucosal diseases. Specifically, subcutaneous administration of this defined parasitic worm product affords protection against joint disease in collagen-induced arthritis, a mouse model of rheumatoid arthritis, which is associated with normalisation of gut microbiota and prevention of loss of intestinal barrier integrity.

immunology↗