Belgium

Aquatic ectotherms are highly vulnerable to climate change, prompting extensive research into the factors that determine their upper thermal limits. A common method to assess thermal tolerance is the critical thermal maximum (CTmax), defined as the temperature at which organisms reach a critical non-lethal endpoint marked by a reversible loss of equilibrium. The physiological mechanisms behind CTmax are still being debated, with a particular focus on mitochondrial dysfunction. Indeed, mitochondria are essential for aerobic metabolism by producing ATP coupled to oxygen consumption through oxidative phosphorylation, which has a highly variable activity and is influenced by temperature. This study aimed to evaluate whether mitochondrial phosphorylation and coupling efficiency are impaired at CTmax temperature in a little-known fish species, the spirlin (Alburnoides bipunctatus), whose long-term persistence in large temperate rivers is questioned under climate change. Wild spirlins were acclimatized at 20°C for two months. Once their CTmax was determined (33.85°C ± 0.12°C), mitochondrial respiration rates and ATP/O ratio (mitochondrial efficiency) were assessed at 20°C and 34°C. Our findings show that mitochondrial complex I respiration is more sensitive to temperature than complex II respiration, and that the ATP/O ratio decreases at CTmax temperature, indicating an increased cost of mitochondrial ATP synthesis at this higher temperature. This observation suggests an increased energy constraint on cellular performance, which may play a role in organismal thermal tolerance. Yet, other organs, such as the heart and brain, are more sensitive to temperature than muscle, underlining the need for further research into mitochondrial efficiency in these organs.

SEB Conference 2025

High temperatures increase respiration but reduce the efficiency of muscle mitochondria in a little-known fish, the spirlin (Alburnoides bipunctatus)

ectotherms

mitochondrial efficiency

climate change

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technical paper

Urban areas provide novel environments with a variety of new selective pressures, which makes them excellent systems to study contemporary evolution in response to anthropogenic environmental change. They are generally warmer than their surroundings (urban heat island effect), which, at high latitudes, can lead to decreased snow cover in cities during winter. Snow acts as an insulator, and thus snow cover loss might lead to increased temperature variation in urban ground temperatures. Insects often escape harsh winter conditions by diapausing under the snow cover, and urban insects might thus be exposed to increased thermal variation compared to rural insects. However, information on the effects of variable temperature on organism physiology and survival is scarce, especially during the winter season.
We performed a common garden laboratory study aiming to understand the effects of urbanisation and daily temperature variation on diapause energetics and termination timing inPieris napibutterflies. For this, we reared urban and rural populations at constant or variable temperature and measured diapause metabolic rate plasticity and diapause termination timing. We then combine these measurements with field microclimate temperature data to construct energy use models, which will help predict phenological patterns under field conditions. We expect that temperature variation will affect diapause metabolism and termination timing. However, if evolution in response to urbanisation has occurred, we expect urban butterflies to be less sensitive to temperature variation than urban ones.
This study will provide valuable insights on the capacity of ectotherms to evolve in response to variable thermal conditions

Effects of urbanisation and temperature variation on diapause in a temperate butterfly

Physiological stress responses to warm temperatures are not fully understood in fish. Activation of the Hypothalamus-Pituitary Interrenal (HPI) axis is essential to trigger adaptive stress responses, leading to cortisol synthesis, the primary stress hormone in fishes. While short-term temperature effects on the activation of this axis have been demonstrated in European seabass (Dicentrarchus labrax), the long-term impact of thermal challenges on the HPI axis has not been investigated in this species. Here, we studied the regulation of the HPI axis in European seabass from the Atlantic population, reared for two years in different thermal regimes reflecting natural environments: Atlantic as control (AT 10.2-18.4°C), and East-Mediterranean as a warm regime (EM 16.7-28°C). Hypothalamus and pituitary samples were collected on individuals from each regime at 183, 400 and 764 days post-fertilization (dpf) and analyzed using RNA sequencing and RT-qPCR to assess gene expression. Our results show a significant down-regulation of most targeted genes in the warm EM regime compared to the AT control. We also investigated the role of epigenetic factors by studying miRNA production (using smallRNA sequencing and RT-qPCR) and DNA methylation (using WGEM sequencing). Finally, scales were used as a key matrix to compare cortisol levels accumulated over time in fish from the two regimes. ELISA assays revealed that there was more cortisol in scales in EM compared to AT regime. This study provides insights into physiological changes in fish due to global warming and improves our understanding of their long-term stress responses.

Investigating the effects of different thermal rearing regimes on the stress axis of the European seabass (Dicentrarchus labrax)

Reactive oxygen species  function as key signals in plant adaptation to environmental stresses like drought. Roots respond to transient water unavailability by temporarily ceasing branching through the acclimative response xerobranching. In this study, we report how a xerobranching stimulus triggers rapid changes of ROS levels  in root nuclei, triggering redox-dependent multimerization of the auxin repressor protein IAA3. Mutations in specific cysteine residues of IAA3 disrupt redox-mediated multimerization and interaction with co-repressor TPL, thereby attenuating IAA3 mediated  target gene repression. Other AUX/IAA proteins also vary in their redox mediated multimerization, revealing a regulatory mechanism that connects dynamic changes in cellular redox status to auxin signalling.  Our study reveals how ROS, auxin and water availability intersect and  shape root adaptive responses, thereby maintaining  phenotypic plasticity in plants.

Redox regulated Aux/IAA multimerization modulates auxin responses

The modern workplace requires teamwork bridging distances, time-zones and cultures using virtual collaboration platforms. As such teamwork is a key employability skill for our graduates, and yet we rarely explicitly teach team skills or how to navigate and collaborate in a virtual environment. Here we demonstrate that integrating in-person (synchronous) and online (synchronous and asynchronous) learning environments can prove an extremely resilient teaching method that allowed continuity during the pandemic, while providing students with these essential skills. But this isn’t just a story about using collaborative software – this is also a student journey into the creative side of science communication. The assessment (which we all know is what matters to students!) is a semester long documentary video team assignment supported by regular compulsory team training sessions and using the Microsoft Teams online collaboration platform. Students interview researchers outside the University of Nottingham (our home university) and create animations, film footage and determine stock footage that is legal to use. I would love to share this journey with you, from both my instructor view and the student perspective and introduce new directions we are exploring with virtual reality.

Virtual Teamwork and Creativity: A Journey in Science Communication

Practical skills development is a core aspect of undergraduate biosciences degrees, creating graduates who can excel in a range of careers, including those that involve laboratory work. However, when we consider the global picture, it is clear that not all students have equality of opportunity to access laboratory spaces to develop these skills and so may not aspire to careers with a practical element. This project describes how we can take lessons learned during the pandemic and apply these to build skills capacity in different areas. In this case, the project described focuses on how learning pipetting and serial dilution skills can be taught outside of the classroom through a “pixel art” competition.
Students at the University of Benin in Nigeria who undertook this skills training were surveyed before and after the training. In addition to increased confidence in pipetting and making serial dilutions, 79% of students who took the survey after the training said that they would be more likely to consider a career with a practical element to it than before they did beforehand. Not only this but 83% of students strongly agreed that they appreciated the opportunity to be creative: with a third of students including the creativity as the most enjoyable aspect of the training. Whilst this project focussed on one cohort of students, the potential for building skills capacity across courses now that local staff can deliver the training independent has the potential to make a significant impact on the country’s infrastructure.

When Pixel art meets bioskills

Since the late 2010s, artificial intelligence (AI), including machine learning and deep learning, has transformed life science research by enhancing the computational analysis of biological processes, natural product discovery, and ecosystem understanding. The surge in high-throughput omics data has made AI-based analyses essential for deciphering complex datasets, with phenotyping facilities becoming crucial in advancing plant sciences.
This presentation focuses on plant metabolism and the role of omics-based predictive analytics in systems biology. By using plant metabolomes as an integrative system, machine learning tools have been employed to address critical areas such as plant resilience to extreme environments and plant-soil interactions. These AI-driven approaches have provided deeper insights into the complex biological systems governing plant life. For instance, metabolic profiles of 24 plant species from the Atacama Desert could predict plant growth elevation with 79% accuracy using only 39 compounds, revealing a shared metabolic toolkit for coping with extreme conditions like freezing temperatures, water deficit, and intense solar radiation.
The presentation also discusses future challenges and opportunities in using AI in plant sciences, offering strategies to advance AI-based predictions of complex plant traits. It highlights AI's potential to revolutionise our understanding of plant biology and its applications in agriculture and environmental conservation.

AI-based metabolome predictions to study complex plant traits

Artificial intelligence (AI) encompasses methods and algorithms that allow machines to perform tasks typically requiring human intelligence, such as image recognition, complex data analysis, and decision-making. Machine learning (ML), a central component of AI, relies on analysing large datasets to identify patterns and make predictions. Unlike traditional methods based on predefined rules, ML enables algorithms to learn from data and improve over time. In plant sciences, ML offers new opportunities for optimising varietal selection, predicting the biological activity of plants relevant to humans, and anticipating their applications in health, cosmetics, or agriculture.
The Camellia genus, known for its polyphenols and oils in cosmetics and its aesthetic value in horticulture, serves as a key example where ML can be impactful. The goal of its study is to identify promising varieties by optimising selection based on their compounds of interest and aesthetic traits. One major challenge is the long wait of 3 to 7 years for the camellia to flower, a critical phase for validating phenotypic attributes. ML applied to predictive metabolomics provides a solution by training models on leaf metabolomic profiles to predict floral characteristics before flowering. This method has achieved prediction accuracies of over 80% for flower shape and colour, revealing key families of metabolites involved.
Beyond accelerating varietal selection, this method could be used to predict biological activities of interest to humans, presenting new possibilities in health, cosmetics, and agriculture.

Metabolomic Analysis of Camellia: Unlocking Phenotypic Insights and Industrial Applications

Far-red light is abundant in natural sunlight, particularly in shaded leaves within plant canopies. Although traditionally excluded from photosynthetically active radiation (PAR), recent studies suggest that far-red can enhance leaf photosynthesis (An ) and reduce mesophyll conductance (gm ) at low light intensities. This triggered an interesting debate: should PAR be redefined?
Previous research, however, was conducted on plants grown in artificial ‘white’ lighting in climate chambers, with spectral conditions differing significantly from natural sunlight. Furthermore, these studies used unrealistic low far-red fractions in control treatments, raising questions about their applicability to field conditions.
To address this, we grew tomato plants under a simulated sunlight spectrum (400-750 nm) at 300 mmol PAR m-2 s-1 . We measured An  and gm  in 25-days-old leaves under normal, increased, and decreased (field-unrealistic) far-red fractions in sunlight PAR. We used a LI6800 and LI7800 Stable Isotope Analyzer system to monitor An  and gm  over 3-4 diurnal cycles, measuring at 5 min⁻¹, under constant and sinusoidal diurnal intensity patterns.
Our results show that increasing far-red—mimicking the shift from unshaded to shaded leaves in the field—did not significantly affect An  or gm . However, removing far-red, comparable to previous studies, reduced An  and gm  throughout light periods regardless of light intensity variation.
These findings suggest that while far-red plays a role in photosynthesis, its effect in realistic field conditions may be less pronounced than previously thought. However, its role can be significant in protected cultivations, where low fractions of far-red frequently occur.

Bridging with Care: Does Far-Red Light Influence Photosynthesis in Field Conditions?

Performances in ectothermic animals are tightly linked to temperature, as metabolic processes shape individuals’ energy balance and constrain their performances. Deviations from the optimal temperature therefore reduce bioenergetic efficiency. Mitochondria generate cellular energy (ATP) via oxidative phosphorylation (OXPHOS), but part of the oxygen consumed is dissipated in the proton leakage (LEAK), lowering mitochondrial efficiency. Previous studies have shown that rising temperatures exacerbate both LEAK and enzymatic dysfunctions, impairing mitochondrial function and potentially compromising organismal performance. Juvenile seabass (Dicentrarchus labrax) inhabit coastal nurseries, where temperature fluctuations can be abrupt and unpredictable. Their ability to cope with thermal variability is therefore critical for growth and survival, yet the bioenergetic mechanisms underpinning their thermal tolerance remain unclear. In this study we tested the hypothesis that the mitochondrial thermal performance of juvenile seabass’ reflects their adaptive capacity in these environments. We assessed the mitochondrial function of wild seabass as rates of oxygen consumption (LEAK and OXPHOS respiration), ATP production, and mitochondrial efficiency (ATP/O ratio) in liver and heart mitochondria across a 12–32°C gradient, encompassing natural and extreme temperature ranges. Consistent with our hypothesis, increased temperature in both tissues led to substantially greater increases in LEAK respiration than OXPHOS respiration. ATP/O declined by ~36% in liver from 12 to 32°C. These findings highlight the strong thermal sensitivity of mitochondrial function in wild ectotherms and suggest that fish juveniles may experience bioenergetic limitations under heatwave events, potentially affecting their growth and survival in nursery habitats.

Too hot to function? Mitochondrial thermal performance of wild juvenile seabass in a changing environment

Global climate change, characterised by rising atmospheric CO₂ and increasing temperatures, has profoundly affected ecosystems, biodiversity, water resources, and human health. Extreme weather events, desertification, and ocean acidification threaten global stability, while agricultural systems face shifting growth patterns, altered pest dynamics, and declining crop nutritional quality. Rising CO₂—from pre-industrial levels of ~200 ppm to over 400 ppm today, potentially exceeding 550 ppm by 2050—modifies plant physiology, altering photosynthesis and biomass accumulation, disrupting carbon-nitrogen balance, and reducing bioactive compound synthesis. Combined with high temperatures, these changes pose risks to global food security and nutrition. 
This study examines the physiological and biochemical responses of kale, rocket, and spinach to elevated CO₂ and temperature. Crops are grown in controlled chambers under ambient (400 ppm) and elevated CO₂ (1000 ppm) conditions, with photosynthetic performance monitored using MultispeQ v2.0 at key growth stages. Growth parameters, including leaf number, plant height, leaf area, biomass accumulation, carbon-nitrogen ratio, and inorganic carbon content, are determined. Biochemical analyses quantify flavonoid, phenolic, and protein content, antioxidant activity, vitamin A and E, polyphenols (HPLC), and minerals (ICP). Bioavailability and digestibility are assessed using Caco-2 cell models. 
Preliminary results from this study indicate that elevated CO₂ may enhance photosynthesis but modulates nutrient composition, with potential trade-offs between biomass accumulation and bioactive compound synthesis. Altered sugar, mineral, and vitamin content could affect global diabetes and micronutrient deficiencies. Further high-temperature analysis is underway to clarify climate stress interactions. Findings aim to inform climate-resilient crop production and food security strategies.

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Effects of urbanisation and temperature variation on diapause in a temperate butterfly

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Too hot to function? Mitochondrial thermal performance of wild juvenile seabass in a changing environment