Constitutive secretion is essential for delivering newly synthesized proteins to the cell surface and extracellular space, enabling the transport of key molecules like antibodies, cytokines, and extracellular matrix components. Disruptions in this pathway are linked to diseases such as cancer, neurodegeneration, and inflammation. Membrane fusion, driven by SNARE proteins, is crucial for protein secretion, but the specific SNARE complexes involved remain unclear. The Peden lab developed a genetic assay using Botulinum toxin (BoNT/X) and cleavage-resistant SNARE proteins, identifying Ykt6 as the only SNARE protein capable of fully rescuing BoNT/X-induced disruption. My research investigates the structural components necessary for Ykt6’s function, using genetic mutations in cleavage-resistant Ykt6 to test its ability to rescue BoNT/X intoxication. Preliminary findings suggest lipid modification may be more crucial than intracellular localization for Ykt6’s function.
Urban ecosystems (UE) are complex spaces where humans, fauna, flora and environmental factors interact. Urban forests, a significant component of UE, provide key ecosystem services (ES) and support a complex network of interdependent biota. However, they are often impacted by several abiotic stressors including the urban heat island effect (UHI), tropospheric pollutants and drought. Understanding the broader negative ecological consequences of stressor-induced trait changes at an ecosystem scale is important, as how these organisms cope with multifaceted stressors remains poorly understood, and often-overlooked. This research aims to address how urban forests, termed “treescapes”, respond to a complex mixture of abiotic stressors, and in-turn, how this modulates tree-insect interactions. The project employs a multidisciplinary approach disentangle the complex interactions between trees, their environment, and dependent biota.
The mechanisms underlying the functional development of the auditory pathway are still largely unknown. In analogy with other sensory systems, it has been hypothesised that spontaneous neural activity present in the early developmental stages affects the formation of the auditory pathway.
However, how immature auditory circuits are assembled and how they are affected by dysfunction of the sensory cells is still poorly understood.
Addressing this unknown is currently impractical in mammals due to the complexity of the nervous system and inaccessibility of the inner ear. Therefore this project aims to use the zebrafish, a small vertebrate with a sophisticated sense of hearing.
Crucially, the small size and transparency of the fish will allow us to use fluorescence imaging to monitor how auditory stimuli are encoded by the ear and the brain in-vivo. When combined with targeted disruption of peripheral activity, this project will unravel the mechanisms behind the maturation of the pathway.
Butterflies display diverse colours that serve functions including signalling and thermoregulation. Butterflies regulate wing temperature through mechanisms such as differential absorption of visible, ultraviolet, and infrared wavelengths. Large-scale studies on colour trends across environments are understudied, and the correlation between reflectivity in different spectra remains unclear. This study examined butterfly wing reflectivity in various spectra and environments. We found that environment and phylogeny, rather than close relatedness, shaped colouration. Butterflies in warmer environments had higher reflectance across all spectra, suggesting limited reflectivity in cooler environments due to niche selection. Size affected brightness most in the ultraviolet spectrum, where smaller wings were more UV reflective, indicating a trade-off between size and UV reflectivity.
To survive changing conditions and adapt to their environment, bacteria maintain a complex cell wall that is continually restructured. One understudied family of enzymes that plays an important role in this adaptive restructuring process are the LD-Transpeptides (LDTs). These LDTs catalyse a number of reactions that reshape peptidoglycan (a major component of the bacterial cell wall) and increase its resistance to stress. Bacteria like Rhizobium leguminosarum, which form an agriculturally important, nitrogen-fixing symbiosis with plants, contain many of these LDT enzymes — often 17 or more. Whilst all of these enzymes belong to the same family, data reveals that some of these enzymes are more important than others when it comes to forming a successful symbiosis. Here we take a closer look at the individual LDT enzymes from R. leguminosarm and attempt to determine their individual contributions to peptidoglycan remodelling and symbiotic fitness.
The aim of this study is to functionally characterize Rex3, a putative exonuclease, by identifying its RNA substrates and determining its role in RNA processing. Additionally, I will investigate the structural features required for Rex3's function in vivo. While sequence homology suggests that Rex3 is involved in RNA metabolism, its exonuclease activity has not yet been experimentally confirmed. Therefore, this project will focus on characterizing Rex3's enzymatic activity and understanding its biological significance in RNA processing pathways.
Insects are declining due to numerous anthropogenic factors, including urbanisation. Although urban greenspaces and interventions such as wildflower areas can be important pollinator habitat, the effects of urbanisation on the quality of floral resources remain poorly understood. Abiotic environmental stressors, e.g., pollution, drought and heat stress, can disrupt plant-pollinator communication, and affect pollen and nectar quality, although no studies have directly tested how the changes in reward quality impact pollinator health. Understanding how abiotic stressors impact pollinators and floral resources is key to urban pollinator conservation. We established a long-term field experiment, controlling habitat quality and floral resource availability across different levels of urban stress, to ask: how do pollution intensity and other urban stressors impact 1) the abundance and diversity of pollinating insects and 2) the quality of floral resources for pollinators?
Enhancers are cis-regulatory elements that boost transcription of their associated genes. Histone acetylation by CREB-binding protein (CBP) bound at enhancers relaxes chromatin structure and increases enhancer accessibility to other transcription factors. When activated, enhancers are transcribed into non-coding enhancer RNAs (eRNA). RNA binding can activate CBP, enhancing its ability to modify histones and promote transcription, highlighting the dynamic interplay between eRNA, enhancers, and CBP in gene regulation⁴. However, the role that RNA structure plays in this regulation has not been fully investigated.
Metalated tetrapyrroles are macrocycles that contain a central metal ion inserted by a chelatase enzyme. These molecules play essential roles in important processes, such as photosynthesis and respiration. Examples include (siro)hemes (containing Fe inserted by a ferrochelatase, FeCH), and chlorophylls (Mg, magnesium chelatase, MgCH). Biosynthesis of the modified tetrapyrroles is via a central pathway that deviates at key points. The chelatase enzymes act at these branches, making their regulation important for balancing the respective end products. For example, phototrophic bacteria such as Rhodobacter sphaeroides can switch between aerobic respiration in oxygenic conditions and photosynthetic growth in anoxic conditions, making the regulation of MgCH and FeCH crucial for balancing flux between the heme and bacteriochlorophyll biosynthesis pathways. This work aims to understand chelatase enzymes and their mechanisms of action and regulation, primarily adopting a structural approach.
Species have evolved life history strategies optimising survival, reproduction, and growth during different life stages. However, this presents an evolutionary puzzle regarding early development. Juvenile mortality is often higher than later life stages, so selection from time-dependent mortality during early stages should favour faster strategies. However, developmental durations vary extensively.
Birds have played a key role in identifying drivers of this variation. Research highlights the importance of intrinsic traits such as body size, physiology and trade offs with later stages. Similarly, ecological traits like diet and migration are also associated.
However, broad scale analyses also report high phylogenetic influence, and ecological conclusions may be confounded with ecomorphology. Shorebirds present an opportunity to limit these considerations. We use modern comparative methods to test traits for associations with this key life history variable within a diverse group.
Hearing loss is the most common sensory deficit in older adults, with the vast majority being age-related or progressive hearing loss. One of the most common causes is genetic mutations that impair the structure and function of the auditory sensory hair cells in the inner ear. These are responsible for translating sound waves into nerve impulses that are relayed to the brain for processing. There has been success in using gene therapy to treat pre-lingual deafness, however it is not known whether the same approach can target more progressive, post-lingual forms of hearing loss. My project investigates pre-clinically if gene replacement therapy via adeno-associated virus (AAV) delays the progression of hearing loss due to mutations in BAIAP2L2, a protein essential for sensory hair cell development and function, and the therapeutic time window for treatment.
Convergent evolution occurs when organisms independently evolve similar traits. Studying Convergent evolution offers a fascinating lens through which to examine how similar environmental pressures, and ecological niches have shaped the evolution of distinct species, and lineages. Studying this process in grasses helps us understand the underlying genetic, and evolutionary traits that enable organisms to adapt to extreme conditions. It provides insights into how different genetic paths can lead to similar adaptive outcomes, highlighting the flexibility and creativity of evolutionary processes.
Selfish genes prioritise their own survival at the expense of that of the whole organism. One such selfish genetic element is an X-linked meiotic driver found on the X chromosome of the stalk-eyed fly species Teleopsis dalmanni. This selfish gene targets and blocks development of sperm carrying Y chromosomes. Male T. dalmanni that carry it can only produce X-bearing sperm, resulting in massively female biased sex ratios. Despite its significant ecological impact, the mechanisms, origins and genetic consequences of the T. dalmanni meiotic driver are unknown. Here, using DNA data from a number of T. dalmanni individuals, I aim to understand the population level genetic impacts of the X chromosome drive system, how it evolved, and what genes underlie it. Using DNA data from a number of T. dalmanni individuals I am employing a range of quantitative genetics techniques to look at the structural differences between chromosomes with and without the X-linked meiotic driver.
Light is crucial for plants as a source of energy and information. Plants detect light using photoreceptor proteins, with phytochromes being red and far-red(FR) light primary photorecepters.However, evidence suggests chloroplasts, where photosynthesis occurs, may act as environmental sensor, detecting FR. Unpublished data showed that in plants lacking phytochromes, several genes behave similarly to those in plants with phytochromes, responding to the oxidation state changes in photosynthetic components due to FR or herbicide. In short, these genes respond to FR detected by the chloroplast, not phytochromes. Among them are members of the Protein Arginine Methyltransferase(PRMT) family which catalyse methylation at arginine residues. PRMT may be components of a retrograde signalling pathway which is the feedback from chloroplast to nuclease modulating gene expression and responses to the environment. This study aim to investigate the role of PRMTs in light signalling in the model plant.
The discovery and characterisation of novel enterococcal bacteriophages is necessary to understand the molecular mechanism that underpins enterococcal surface recognition. The Enterococcal Polysaccharide Antigen (EPA) has been described as an essential cell envelope component for phage infection. Little is known about Enterococcal phage receptor binding proteins and how EPA structure contributes to recognition by these viruses.
We isolated 56 phages from different environmental samples that target clinical strains of Enterococci. Using efficiency of plating assays, we successfully characterised the substrate binding specificity of 6 isolated phages against several EPA structural modification OG1RF E. faecalis mutants. This work revealed a high diversity of cell surface recognition strategies by phages and is an important step towards identifying distinct classes of phages that target different surface structures for the design of phage cocktails as therapeutics against these pathogens.
Osteogenesis imperfecta (OI), often referred to as brittle bone disease, is a genetic condition with characteristic bone fragility and deformation resulting in impaired quality of life. The majority of OI cases result from mutations in the genes responsible for the production of type I collagen, a key component of bone. As of today, no gene therapy approaches for OI exist and current treatment options provide only minor improvements in disease condition. My project seeks to develop a gene therapy approach for OI, in which I will first generate bone cells (osteoblasts) from patient-derived stem cells both with and without OI-related mutations and perform detailed analysis to establish any differences in the resulting tissues in vitro. I then aim to devise a gene therapy strategy that utilises gene editing with CRISPR/Cas9 to silence the mutant copy of the collagen gene. Finally, I will evaluate the efficiency of my gene therapy approach in alleviating any observable OI characteristics.
Drought affects plant physiology, but responses vary among ecotypes. This study examined 53 natural Arabidopsis ecotypes from various geographical regions under well-watered and drought conditions. Growth rate was measured by projected rosette area, stomatal closure by rosette temperature, and photosynthetic efficiency by chlorophyll fluorescence. All ecotypes showed a general drought response: reduced growth, higher stomatal closure (high temperature), and decreased photosynthetic efficiency. However, the timing of these changes varied, with more drought-tolerant ecotypes responding later. Some ecotypes showed possible trade-offs, such as greater stomatal closure under drought in those with high stomatal conductance in well-watered conditions. Reduced growth while maintaining photosynthetic efficiency also suggested a trade-off between growth and photosynthesis. These findings underscore the diverse responses to drought, providing valuable insights into plant adaptation strategies.
This poster provides an overview of my research into patterns of colour in the global bird trade. I make use of global trade data and novel colour data extracted from pictures of museum specimens. It shows the creation of the three colour metrics I've developed for this/ colourfulness, colour uniqueness, and colour categories. Colourfulness is a measure of the range of colours present on a bird. Colour uniqueness measures how different a bird's colouration is from the global average. Colour categories divide the colour values of each standard pixel on the bird pictures into a specific colour. Using these, we can see there's a link between increasing colourfulness, colour uniqueness and likelihood of trade for a species. There is a lot of inter-family variation with colour being differently important for different families. Trade also seems to prefer birds with many colours rather than monochromatic ones. These metrics can be used for future research across spatial and temporal axes.
Fat breakdown is a tightly regulated process spanning multiple compartments in a cell to generate energy. Certain fats called fatty acids (FA) are stored in organelles called lipid droplets. Some FAs pass through organelles called peroxisomes for partial breakdown before full breakdown. For FAs to move from lipid droplets to peroxisomes, it is important they make contact. Recent evidence shows organelle membrane changes control contact formation. To date, details of contact regulation remain poor, particularly during stress.
Here, we take a discovery approach to investigate how peroxisome-lipid droplet contact sites respond to peroxidative stress. By combining microscopy with modified HeLa cells and cutting-edge membrane labelling techniques, we observe changes in contact frequency, dynamics, and lipid droplet motility. Meanwhile, we attempt to identify novel lipid droplet contacts with other organelles. Our findings will help resolve the mechanisms of this understudied interaction.
Despite their potential as therapeutic agents, C. difficile phages remain understudied. Therapeutic development has been slow due to a lack of naturally occurring lytic phages and difficulties in laboratory preservation. This knowledge gap hinders our understanding of their host interaction mechanisms, and while previous research has provided insights into structure and function, further investigation is necessary.
Our project aims to understand the fundamental questions that have puzzled phage researchers for decades. We are utilising two well-characterised phages as templates for detailed mechanistic analysis. We will report on the function of various structural proteins in phage infection and attempt to answer questions such as how the tail contracts, how the tail length affects infection, how DNA moves from phage to the cell, and more. This research will advance phage therapy by informing the development of more effective phage-based treatments.
The vast array of colours exhibited by animals is one of the most striking aspects of biodiversity. Animal colour phenotype plays a key role in fundamental processes such as predator-prey interactions, thermoregulation, and sociosexual signalling. Moreover, animal colouration is a trait which is highly valued by humans, with colourful species often chosen as national animals or representatives of conservation efforts. Despite this, we still do not have a clear understanding of how diversity in animal colouration phenotype is distributed geographically or phylogenetically, nor of how this diversity may be threatened by anthropogenic environmental change. Here, we develop a novel machine-learning-based pipeline to quantify holistic colouration phenotype from specimen images, and apply this pipeline to characterise colouration diversity in birds. We then examine whether this diversity is threatened disproportionately by anthropogenically induced extinctions.
This project investigates the complex interactions between climate change and chemical pollution, focusing on their combined impacts on marine fish communities in the North Sea. Fish species differ in their capacity to accumulate contaminants such as heavy metals and dioxins, which can biomagnify through the food web, posing risks to top predators, including seabirds and marine mammals. Climate-driven shifts in fish distributions alter community composition, potentially increasing or reducing contaminant risk depending on species traits. These ecological changes could disrupt established contaminant pathways, creating new hotspots of risk. Using climate projections, future shifts in species distributions can be predicted, allowing for the assessment of how contaminant risk may evolve under different warming scenarios. The North Sea, with its extensive long-term biological, chemical, and environmental monitoring, provides an ideal case study for examining these complex interactions.
Ribosomes are molecular machines found in all living organisms that translate messenger RNA into proteins. They are composed of both proteins and a structural form of RNA known as ribosomal RNA (rRNA). Historically, it was thought that ribosome composition was homogeneous within a species, and that ribosomes did not play a role in regulating protein synthesis. However, more recent studies suggest otherwise with evidence that heterogeneous components may contribute to protein synthesis selectivity, termed ribosome specialisation. My project focuses on one example of ribosome heterogeneity - Bud23-mediated methylation of guanine 1575 in 18S rRNA. By producing a catalytically inactive mutant of Bud23 in yeast, I aim to analyse differences in the proteins produced by modified and unmodified ribosomes, under both homeostatic and stress conditions. Here, I show how I selected candidate mutants and screened for catalytic mutant-specific phenotypes.
Through a phenomenon termed ‘phenotypic plasticity’, individuals can change their phenotype within a generation in response to the environment. Phenotypic plasticity is beneficial as individuals do not need to wait for evolution to make adaptive changes to their genes over several generations in order to cope with environmental change. To predict how phenotypic plasticity will impact populations we need to understand how evolution acts on it and to do this, we need to know the molecular mechanisms involved in phenotypic plasticity. One such mechanism is alternative splicing, which produces different products from the same genes. The fruit fly (Drosophila melanogaster) displays phenotypic plasticity in response to environmental stressors such as change in diet. We will use whole transcriptome analysis to assess differential alternative splicing occuring in response to environmental stressors in different genetic backgrounds, allowing us to link phenotypic plasticity to the genome.
During development, the mammalian cochlear hair cells elicit spontaneous electrical activity to induce neurotransmitter release onto the auditory nerve fibre, which is crucial to the refinement of both the cochlear sensory epithelium and the auditory pathway.
Developing outer hair cells (OHCs), which later play a key role in cochlear amplification, have been shown to have spontaneous activity in ex vivo preparation, but whether this activity is present in vivo and triggers activity in afferent neurons, remains unknown.
In this project, I use a novel technique combining surgical procedure and 2 photon Ca2+ imaging to record spontaneous Ca2+ activity in the cochlea in neonatal mice in vivo. I found that pre-hearing OHCs elicit spontaneous Ca2+ transients in the first postnatal week, before their maturation. In the future, this approach will allow me to uncover the mechanisms regulating spontaneous activity in OHCs and its influence on the functional development of the auditory system.
The rate at which crops grow is dependent on many extrinsic factors, many of which are climate driven; e.g., precipitation, temperature, humidity, etc. Applying a data driven approach, as opposed to more traditional mechanistic models, allows us to explore the interplay between growth and climate, without being constrained to fixed input variables.
However, data driven or machine learning (ML) approaches, despite performing well, suffer from the concept of the black-box affect; i.e., the "reasoning" driving the decision making is difficult (impossible) for a human to interpret. This dilemma produces a challenge for researches whose goal is to produce pragmatic innovations, as end-users or stakeholders struggle to trust these models.
The solution is applying explainable AI (XAI) techniques, such as Integrated Gradient (IG). These allow us to produce more transparent interpretations of these models, essentially associating an importance value with each variable.
Streptococcus pneumoniae is a leading cause of morbidity and mortality globally. While β-lactam antibiotics are the primary treatment, rising antibiotic resistance threatens their effectiveness. Resistance is commonly linked to alterations in penicillin-binding proteins (PBPs), but other genetic factors remain underexplored. To identify novel genetic contributors to penicillin resistance, we generated laboratory S. pneumoniae strains capable of surviving low penicillin concentrations. Whole-genome sequencing revealed mutations in three genes. The most common gene affected, pde1, was fully described in 2023. Two additional genes were identified: one involved in cell wall regulation and another in lipoteichoic acid synthesis. These findings highlight previously unrecognized early-stage resistance mechanisms that operate independently of PBPs and could inform new intervention strategies to counteract early resistance development.
Phosphorous is an essential nutrient for plants, but often scarce enough in soil that crop growth will be limited by its unavailability. Bacteria can release phosphorous from organic matter in soil using enzymes, but usually only do so for their own benefit. I am trying to develop a plasmid, which is a set of genes that spread through bacteria independently of their original host's genes, that cause bacteria to increase their production of phosphate-releasing enzymes. The challenge is to develop a plasmid that incurs a low enough cost to its host to spread through a crop root microbiome, and increases phosphate levels enough to promote plant growth. This will allow for better crop yields with less phosphorous fertiliser.
Rivers, despite being only 2.5% of the world's water, are essential for the environment, containing 9.5% of species. The European eel demonstrates catadromous behaviour and migrates into rivers, lakes, and coastal environments to feed and grow before returning to the Sargasso Sea to reproduce. However, weirs and dams threaten 30% of freshwater fish species, including the European eel, by obstructing migration. This study will assess the impact of weirs and dams on the European eel, focusing on Rivers in South Yorkshire using environmental DNA, the genetic material released by an organism in its environment without the acquisition of living individuals, and DNA metabarcoding will assess river biodiversity. Thus, it aids the conservation of this endangered species across diverse habitats by identifying management priorities such as barrier management, potentially leading to implementing measures to aid eel passage and habitat preservation.
Arbuscular Mycorrhizal Fungi (AM fungi) colonise the roots of around 80 % of terrestrial plant species engaging in a carbon for nutrient exchange between fungi and plant. Nitrogen cycling microbial communities are responsible for soil derived nitrous oxide emissions, and AM fungi have previously been shown to drive changes in these communities, decreasing emissions of this potent greenhouse gas. Agricultural soils are UK’s largest source of nitrous oxide, making them a a key target for net zero, requiring novel approaches to tackle the problem. Genetically modified barley that show either increased or decreased AM fungal colonisation relative to their wild type progenitor were used to establish a field trial to investigate whether Am fungi were capable of reducing nitrous oxide emissions in cropped, fertilised soil systems.
Stomata are microscopic pores on the surface of leaves which act as the gatekeepers to the leaf, regulating its ability to take in carbon dioxide intake at the expense of losing water. These pores are flanked by a pair of guard cells, which open and close the stomata by exchanging water to inflate or deflate. In doing so, these guard cells sustain considerable stress, analogous to being pushed from the inside with 50 atmospheres of pressure. The cell wall which wraps around these cells must therefore be extremely strong and flexible to withstand these pressures while opening and closing reversibly. I have been studying the structure of these walls at the cell scale and nanoscale, hoping to understand exactly how the various polymers making up the cell wall come together to determine its ability to achieve this remarkable strength and flexibility.
Long-tailed tits are social birds with a cooperative breeding system, where individuals help raise offspring that are not their own. This behaviour, known as "helping", typically occurs among relatives, which is beneficial as then helpers and helpees share many genes. While it is clear that these birds can distinguish between relatives and non-relatives, the exact mechanisms they use remain uncertain. My research explores whether long-tailed tits use their sense of smell to recognize kin. Specifically, I examine the composition of preen oil, a substance that in other species acts like a "perfume," conveying information about health and identity. I aim to determine whether preen oil contains information about genetic relatedness in long-tailed tits. My findings reveal that preen oil composition differs between adults and chicks, as well as between breeding and non-breeding seasons. However, I do not find evidence that preen oil is more similar among family members.
Pancreatic ductal adenocarcinoma (PDAC) is characterised by a stiff tumour environment and has no curative therapies. This stiff environment is produced by inappropriate deposition of components, known as the extracellular matrix, that are normally tightly regulated to support pancreatic cells. Despite the emergence of novel targeted therapies, chemoresistance continues to arise. Hence, we hypothesise the increased stiffness of PDAC tumours induces resistance to chemotherapy. By modelling the stiffness of healthy and diseased pancreas using polyacrylamide gels, my project will uncover how pancreatic cancer cell signalling is altered as a product of matrix stiffness, and how changes to the cell cycle and DNA damage response allow cells to escape chemotherapy. Preliminary evidence suggests PDAC cells grow better on stiffer gels and are more resistant to chemotherapy than on softer gels. Thus, harnessing the mechanisms underlying these pathways may allow us to bolster treatment efficacy.
The study of regenerative biology aims to understand how organisms naturally replace injured cells and tissues. Zebrafish larvae having excellent regenerative ability can be used as a model to study cellular and molecular aspects of regeneration. My project aims to understand how wound signals are able to activate the redevelopment of tissues during larval tail regeneration. Two signalling pathways (Hedgehog (HH) and transforming growth factor-β (TGF-β)) play a crucial role in larval regeneration. If either pathway is inhibited, regenerative cells are not recruited to the injured site. However, the detailed links between signals are poorly understood. My data supports the model that after tail excision TGF-β is induced by HH along with reactive oxygen species (ROS) which is produced at the wound site. The TGF-β then inhibits HH expression as part of a negative feedback loop. We hope that in the long term our research may aid in the development of new therapies in regenerative medicine.
Avian population declines arising from eggshell thinning induced by chemical exposure is now typically regarded as an historical threat. Evidence has started to emerge, however, that a wide range of pollutants are abundant in the environment that could generate eggshell thinning. These include historical ‘legacy’ pollutants and more novel emergent pollutants. Using a systematic literature review approach we provide an assessment of the potential for six main chemical groups, those being DDT and its metabolites, PCBs, PBDEs, PFASs, NSAIDs and neonicotinoid pesticides, to induce eggshell thinning. Assessment of the quantity and quality of evidence highlight that whilst much additional research is needed a number of these pollutants, in addition to DDT, have potential to induce avian eggshell thinning – with potential demographic consequences.
Current evaluation of the impacts of chemicals and their mixtures on freshwater ecosystems relies heavily on single- and multi-chemical effects on individual species. However, species do not exist in isolation, and a mechanistic understanding of how chemicals and their mixtures impact species interactions is essential if we are to extrapolate from single species, single chemical studies to assessing the impact of multiple chemicals on multispecies assemblages in ecosystems. Here we demonstrate the use of a consumer-resource system to begin to disentangle the complex effects of chemical mixtures on ecological communities. We present the results from a series of crossed-design binary-chemical consumer (grazer)-resource (primary producer) interaction experiments using the freshwater snail, Potamopyrgus antipodarum and the freshwater diatom, Nitzschia palea.
Plants release exudates, manipulating the soil surrounding their roots and creating a region called the rhizosphere. Microbiota inhabiting the rhizosphere are adapted to utilise these exudates, composed of simple (e.g., organic acids) and complex (e.g., polysaccharides) carbon sources. Whilst there have been advances in understanding the plant rhizosphere microbiome, the role of polysaccharides in driving microbiome assemblage remains limited. Bacteroidota, an abundant soil bacterial phylum, are typically enriched in plant microbiomes. In the human gut, they degrade dietary polysaccharides, but their role in soil has received less attention. These bacteria possess Polysaccharide Utilisation Loci (PULs), encoding proteins for complex carbohydrate metabolism. However, the mechanisms enabling Bacteroidota to degrade polysaccharides in soil remain unclear. My work identifies specific PULs linked to plant polysaccharide utilisation and their impact on microbiome assemblage.
As one of the highest emission-intensive foods, chocolate presents a significant challenge in meeting consumer demand and sustainability goals. Focusing on carbon sequestration and climate resilience, this field trial aims to explore the potential of agroforestry and enhanced rock weathering (ERW) as a dual strategy towards net zero cocoa. We here describe how agroforestry systems, particularly multistrata systems such as Cabrucas, can enhance carbon sequestration and delve into the mechanisms by which ERW can augment these benefits, focusing on its impact on carbon accrual, nutrient release, and soil health. This research underscores the importance of integrated approaches to address the complex challenges facing the cocoa sector. Further research is needed to quantify the economic and social benefits of agroforestry and ERW, as well as to develop best management practices for different agro-ecological contexts.
Tissue stiffness is a main regulator during development regulating cell behaviour such as cell proliferation or cell migration. It also plays a major role in diseases such as cancer and fibrosis. However, the underpinning mechanisms are incompletely understood.
My project- if successful- will determine the impact of stiffness on the cell surface proteome, which might help to identify stiffness regulated pathways. Furthermore, insights into the underpinning mechanism might help to develop novel anti-cancer or anti-fibrosis strategies.
Freshwater ecosystems are under threat from multiple environmental stressors yet play a disproportionate role in global biodiversity, containing 10% of described species despite covering 1% of the planet. Ecological models of species interactions are a powerful tool for predicting these stressors' effects by providing an interface between traits and community dynamics. Although considerable trait data exists to inform such models, difficulties with accessibility and species bias often leads to species at lower trophic levels being assigned to larger groups. This aggregation may impact the capacity for models to predict community responses to climate change including diversity, stability and robustness to extinction. To address this, I have produced a trait database for phytoplankton and zooplankton providing information on body size, phylogeny and functional group membership for over 3500 species across 41 countries.
Commercial selective logging in tropical forests leads to canopy layer disturbance and the subsequent rapid growth of ruderal, photophilic lianas. Lianas negatively impact tree performance but can benefit fauna by providing fruits, nectar, nests and connectivity. Complete climber removal is used for tropical forest restoration, but a key question is understanding how different intensities of liana removal impact forest regeneration. Using a 320-ha liana removal experiment in Sabah, Malaysian Borneo, we explored the impact of a spectrum of liana removal intensities on liana regrowth, tree growth and carbon storage. We find that the effect of liana removal intensity on overall adult tree growth is positive, but that there was no impact of liana removal at any intensity on overall juvenile tree growth, tree or plot biomass, or carbon stocking. The results also revealed that responses to liana cutting is taxonomy-dependent, and that this could be due to differences in functional traits.
Regenerative farming practices have been heralded as an environmentally friendly alternative to conventional, intensive farming practices. The use of leys within crop rotations can improve soil health and promote the biodiversity of microfauna within the soil. A healthy and diverse soil microbial community can promote the health of crops grown in the soils following the leys. However, it has been reported that the crops subsequently grown after a ley suffer a growth penalty. We hypothesise that chemicals secreted by roots of the ley crops are responsible for recruiting and maintaining a healthy soil microbiome whilst negatively impacting the growth of subsequent crops. This project seeks to untangle these probiotic and growth-suppressive chemicals which can increase our understanding of how plants shape the soil microbial community.
Cells are often required to move together as groups to help organisms develop properly and to heal wounds. How groups of identical cells migrate has been studied extensively, but this migration can also be made up of different types of cells. This mixed-cell movement is important for early development and plays a role in cancer metastasis and the formation of secondary tumours. However, how different cell types can co-ordinate their movement remains poorly understood.
To study this, I am using fruit fly embryos, where we recently discovered four different cell types that migrate together in the developing gut. This makes it a great model for studying how different cells can work together to move in a co-ordinated manner. My goal is to uncover the mechanisms that enable collective migration in mixed-cell populations.
Enterococcus cecorum is an emerging poultry pathogen that infects the free thoracic vertebra of chickens, racing pigeons, and pekin ducks causing osteomyelitis, spondylitis, and femoral head necrosis. Rare cases have also been observed in humans where contaminated meat and domestic animals are thought to act as carriers. The spread of the bacteria has been aided by high levels of antimicrobial resistance as well as the emergence of divergent clonal lines which has allowed the organism to improve its pathogenic potential within poultry. To investigate the traits which may be contributing to the spread of these bacteria we investigated both the genomic and phenotypic characteristics of 190 E. cecorum isolates to identify key differences between clinical and non-clinical strains. We identified clinical isolates were phylogenetically distant from non-clinical strains as well as containing high levels of antibiotics resistance and altered cell envelope composition.
Pancreatic cancers are one of the most aggressive forms of cancer because they manage to survive and grow in nutrient-deprived environments. We hypothesised that Pancreatic Ductal Adenocarcinoma (PDAC) cells could remodel their Extracellular Matrix (ECM) to produce nutrients under nutrient-limiting conditions. Using PDAC cell lines, our preliminary data showed that Matrigel, a component of the ECM supports the proliferation of PDAC cells in Glucose and Glutamine deprivation conditions, as well as in Tissue Interstitial Fluid Media (TIFM), which has been reported to mimic the physiological nutrient availability in PDAC tumours. Importantly, our data showed that the presence of Matrigel can alter the metabolism of PDAC cells and that arginine metabolism is upregulated when the cells are grown under starvation on Matrigel. Overall, our study has established that the ECM can alter the metabolism of PDAC cells to support their cell growth under nutrient-limiting conditions.
Trace metals, such as copper, are essential for life but can become toxic in excess. Traditionally, ecotoxicology has focused on the dose-response of individual metals, often lacking mechanistic insights and overlooking mediating factors like nutrient availability. Using Drosophila melanogaster, a powerful genetic model, I investigate how essential metals interact with nutrients to alter toxicity thresholds. Preliminary findings suggest that dietary composition can impact an organism's ability to cope with copper toxicity during development. Additionally, manipulating a key metal-regulating transcription factor alters the response to copper toxicity under different protein diets, suggesting nutritional dependencies in metal regulation. By incorporating functional genetics into ecotoxicology, we can better understand how organisms handle metal exposure, predict species sensitivity to complex scenarios, and link molecular mechanisms to environmental impacts.
Plants in many regions of the world are experiencing greater drought. They are also experiencing greater nitrogen supply through fertilization and eCO2. Understanding how nitrogen and CO2 control plant responses to drought is therefore critical. Elevated CO2 can increase plant tolerance to drought by closing stomata and increasing water use efficiency. High nitrogen supply may, in contrast, reduce plant tolerance to drought by increasing transpiration. However,the relative importance of CO2 and nitrogen supply in controlling plant drought responses is not known. Little is known about how nitrogen and CO2 interact in combination, to control plant drought responses.This project will use a variety of plant physiology approaches to determine the importance of nitrogen and CO2 in plant drought responses. It will include assessments of photosynthesis, transpiration, stomatal conductance, and WUE in plants exposed to either increased nitrogen supply, eCO2, or both in combination.
Urbanization is rapidly accelerating, and globally most humans now live in urban areas. Indonesia, for example, has the second highest urbanization rate in Asia, with it increasing from 33% to 51% in twenty years (1992-2012), with most of this concentrated in Java. Urbanization's effects depend on the rate and magnitude of environmental change, but generally urban development causes a decline in biodiversity. Although urbanization is already established as a major driver of biodiversity loss and biotic homogenization, empirical studies from tropical locations, especially ones focusing on invertebrates are limited. This research will tackle this gap. It will address questions regarding how butterfly communities respond to urbanisation in Java, Indonesia, focusing on changes in biodiversity (species richness and abundance), the species traits associated with tolerance to urbanisation, and how butterfly genetics, colour and morphology are influenced by urbanization.
My project is focused on studying how the stringent response affects ribosomal maturation and regeneration in Staphylococcus aureus. The stringent response is a stress signal that bacterial cells activate when they are stressed, for example, due to low nutrients in their environment. The activation of this response results in a down-regulation of a variety of essential pathways in cells such as translation and transcription, with the end goal of reducing the energy expenditure of the cell allowing it to enter a hibernation state. This results in cells not being able to continue dividing. The effects of also affect the process of ribosomal biogenesis/maturation. Ribosomes are complex machineries that are responsible for the production of proteins in cells, understanding the maturation process of these particles could allow for broad-spectrum antibiotic discovery.
Shelf seas are among the most productive ecosystems on Earth, playing a crucial role in nutrient cycling, climate regulation, and food production. Benthic macroinvertebrates are key components of these ecosystems, forming a highly diverse component of marine food webs. Despite the ecosystem services they provide, the high sensitivity of benthic invertebrates to external stressors is causing shifts across benthic habitats globally. While benthic communities are not routinely monitored at large spatial scales, many smaller surveys have now been aggregated into openly available biodiversity databases. These datasets can be combined with species traits data and phylogenetic information to quantify benthic community variation across time and space, highlighting trends across multiple dimensions of diversity. The spatial mapping of each dimension can provide valuable insights for marine conservation, enabling the prioritization of management strategies throughout the European marine benthos.
Phosphoinositides are phospholipids that provide identity to membrane-bound compartments. In phagocytosis, they temporally coordinate effector molecule delivery to the maturing phagosome. PIKfyve, a phosphoinositide 5-kinase, functions in a complex with the phosphatase Fig4 and the scaffold protein Vac14 to convert PI(3)P to PI(3,5)P2.
Activation and regulation of the PIKfyve complex remain poorly understood. Loss of PIKfyve causes swollen endosomes and delayed bacterial killing due to impaired V-ATPase and hydrolase delivery. In mammalian cells, loss of Vac14 or Fig4 causes neurodegeneration, but their roles in phagocytosis are less explored.
I made Vac14 and Fig4 CRISPR knockouts in Dictyostelium discoideum, a slime-mould amoeba and professional phagocyte. Fig4- cells show minimal phenotypic differences from WT, while Vac14- cells exhibit reduced proteolytic activity. Notably, PIKfyve localises to the phagosome membrane in Vac14- cells but fails to convert PI(3)P to PI(3,5)P2.