Biology Education

Department of Biology | Lund University

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Understanding work rate in breeding birds

One of the cornerstones of life history theory is that there exists a trade-off between current and future reproduction. What that really means is that if you invest a lot into one breeding attempt you will have less available energy for future reproductive attempts or for your own self-maintenance (thereby possibly reducing lifespan). Famous rocker Neil Young once sang, “It’s better to burn out than to fade away” and in a way the whole point of this area of research is to understand if he was right or not (perhaps not for rock stars, where other things than lifetime reproductive success might be of greater importance).

In birds, one of the most common ways to investigate this trade-off is to manipulate brood size, thereby either making it easier or harder for parents to feed all their young. The golden standard for such studies is to assume that work rate differs between parents with different brood sizes and even though there are studies that confirm this pattern the effects of such a manipulation seem to vary quite substantially between years and with other environmental factors.

Thus, we are missing one essential component in the puzzle, which is: how is feeding frequency (work rate) truly affected by brood size manipulations?

This question has been answered before, but only using short snapshots in time, counting feeding events over hours and possibly a few days. However, to understand the full effect of brood size manipulations on parental investment and work rate we need to know the energy spent throughout the full nestling period. Work rate is not a constant trait and varies over time as nestlings grow older and there could be differences in these patterns, according to brood size.

You will conduct the fieldwork in the period April-June in a population of nest-box breeding blue tits (Cyanistes caeruleus) in the scenic landscape surrounding Lake Krankesjön, circa 20 km east of Lund. You will get hands-on experience of capturing, handling, and ringing birds and the possibility to work with multiple techniques involved in measurement of feeding frequency and possibly also other areas of research. To get the most out of the project, it would be advantageous to have some prior experience of handling birds, and a driver’s license is required to be able to conduct the field-work. This is a project that can be modified and suited to your own interests – it would for example be easy to add other components into this framework (i.e. phenology, immunology, body temperature regulation etc.) – so please contact me, should you find this topic interesting.

fredrik.andreasson@biol.lu.se

https://portal.research.lu.se/en/persons/fredrik-andreasson

 

 

January 30, 2025

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Biology

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Immune response and inflammation in myocardial infarction and myocarditis: underlying mechanisms and novel treatments

We are inviting students interested in immunology and cardiovascular disease to perform their Master’s Degree project at the Cardiac Inflammation Research Group, CRC Malmö. Our group studies immune and inflammatory mechanisms involved in myocardial infarction, atherosclerosis and myocarditis. By using animal models and in-vitro studies we investigate the underlying disease mechanisms and aim to develop new treatments for translation into the clinic. In parallel, in our large cohorts of myocardial infarction patients, we are looking for new pathways and biomarkers that are important for the development of heart failure and other complications. You can read more about our research on our website and in our recent publications in the European Heart Journal (Marinkovic et al, 2019), Circulation Research (Marinkovic et al, 2020) and Critical Care (Jakobsson et al, 2023).
Our experienced post-docs are leading the work and provide hands-on supervision for master’s and PhD students. Our projects include in-vivo work with mouse models of myocardial infarction, atherosclerosis or myocarditis. We measure cardiac function by echocardiograpy, perform in-depth analyses of immune cell populations by flow cytometry, histology and immunohistochemistry. We have also developed an extensive database of single-cell sequencing data (CITEseq) for the detailed study of gene and surface protein expression in cells isolated from the heart, blood and immune organs of mice with myocardial infarction and myocarditis. In-vitro, we are using cell culture experiments (immune cells, cardiomyocytes, endothelial cells) to analyze cell function, gene expression, signaling pathways, and cellular metabolism (Seahorse). We use a wide range of methods such as microsurgery, immunohistochemistry, histology, light and fluorescent microscopy, ELISA, RT-PCR and Western Blot.
Our ongoing projects include:

  • Study the role of novel neutrophil sub-populations identified in our earlier research in the pathogenesis of myocardial infarction and myocarditis.
  • Study the impact of a treatment developed in our lab, based on blockade of the pro-inflammatory neutrophil mediator S100A8/A9, on the immune response in myocardial infarction and myocarditis.
  • Develop new immunomodulatory treatments against cardiac inflammation by using individual metabolites derived from the Krebs (tricyclic acid) cycle.
  • Identify immune cell populations responsible for increased vascular inflammation and atherosclerosis after a myocardial infarction.

If interested, please contact Dr. Alexandru Schiopu, group leader, at Alexandru.Schiopu@med.lu.se

January 30, 2025

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Molecular Biology

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Vision in Changing Waters – How do predatory zooplankton adapt to variable and changing light environments?

The water flea, Polyphemus, uses its large, highly-specialised eye to hunt for prey and navigate its habitat. They live in freshwater lakes that can vary tremendously in colour, clarity, and brightness. These habitats are also impacted by human activity that further changes their light conditions. This project aims to explore the capabilities of Polyphemus to adapt their visual system to these dynamic and challenging conditions.

Projects:
Projects of varying lengths are available and potential techniques may include behavioural experiments, molecular characterization of visual gene expression, environmental light measurement, and anatomical investigations. Both BSc and MSc projects are offered. 

Read more about this project here

Contact: Dr. Michael Bok, Biologihuset B320
michael.bok@biol.lu.se

January 29, 2025

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Biology

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How are bacteria coping with stress?

Just like us, bacteria often have to deal with stress. However, stress for bacteria is a bit different from the stress we are used to – it is something that causes damage to the cellular macromolecules: membranes, proteins, and nucleic acids. It can be chemical stress, caused by harmful compounds, or physical stress, such as heat. A limited supply of nutrients can also be regarded as stress. Bacteria have developed stress responses, which aim to temporarily increase tolerance limits. These stress responses are often specific; each specialized in a particular kind of stress. Some stress responses facilitate bacterial transition from a free-living organism to a host-invading pathogen.

The aim of this project is to investigate, at the molecular level, how the soil-living bacterium Bacillus subtilis deals with various types of stress. This bacterium can form structured multicellular communities called biofilms. Biofilms contain genetically identical cells that give rise to phenotypically distinct cell types, such as, for example, motile cells, surfactin producers, sporulating cells and matrix-producing cells. Biofilms provide a protective environment that enhances resistance to antibiotics and play an important role in the pathogenesis of many medically important bacterial pathogens. By studying how biofilms are affected by stress, we could develop strategies to disperse them.

30-60 cr MSc thesis project, flexible start date.

Qualifications needed: Good knowledge of molecular biology and microbiology.

If you are interested to get more information on current projects, please contact Claes von Wachenfeldt (claes.von_wachenfeldt@biol.lu.se)

January 29, 2025

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Molecular Biology

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Investigating the true nature of the Mitochondrial Calcium Uniporter Regulator (MCUR)

Mitochondria are essential cellular organelles involved in energy production via oxidative phosphorylation (OXPHOS), metabolite synthesis, calcium homeostasis, and stress responses. Despite their critical roles and extensive research on plant mitochondria, many aspects of their biology remain unclear. Advancing our understanding of these organelles will help address future challenges in food production posed by climate change and a growing global population.

Calcium is a key cellular component, acting as a second messenger in signaling pathways and playing key roles in ATP production and mitochondrial signaling processes. Calcium uptake into the mitochondrial matrix is regulated by the mitochondrial Ca²⁺ uniporter (MCU), a multimeric membrane channel complex. This complex includes regulatory proteins, one of which was reported to be the Mitochondrial Calcium Uniporter Regulator (MCUR). Although MCUR was identified in mammalian cells in 2015, its precise role and function are still debated. Conflicting studies suggest it regulates the MCU but that it is also is part of Complex IV in the Electron Transport Chain (ETC), or even functions as a proline transporter in yeast. While mammalian and yeast studies present discordant findings, MCUR proteins remain completely unstudied in plants.

This project aims to investigate the MCUR family in Arabidopsis thaliana to clarify their roles and the processes they are part of. Using genetic tools like CRISPR-Cas9 and insertional mutagenesis, knock-out mutants will be generated and analyzed through physiological and phenotypic studies. Protein-protein interaction assays and -omics analysis, such as transcriptomics and proteomics, will provide further insights into MCUR functions.

This research offers students the opportunity to contribute to a novel field while gaining experience in advanced physiological and molecular techniques. For more information, contact Olivier Van Aken (olivier.van_aken@biol.lu.se).

January 29, 2025

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Molecular Biology

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Understanding the impact of epigenetics on cell function and human health

DNA molecules in our cells are packaged around histone proteins to form a structure called chromatin, which preserves cell function. Chromatin contains so-called epigenetic information (for example, in the form of post-translational modifications of histones) that safeguards transcriptional programs and promotes genomic stability. Unsurprisingly, mutations in chromatin proteins and alterations of epigenetic information disrupt cellular processes and contribute to human disease.

How do epigenetic alterations cause human disease?

In our lab, we model disease-associated epigenetic aberrations in human cells, with the aim of understanding how these aberrations affect DNA repair, gene transcription, and cell division. The methods employed include human cell culture, advanced molecular biology and biochemistry, genomics, and high-content microscopy.

I am looking for a highly motivated master’s student to undertake a wet lab project. Interest in chromatin biology and epigenetics, transcription, and/or DNA repair is essential for the project.

You will be joining a newly formed lab, embedded in a stimulating research environment at BMC A11, and benefit from regular hands-on supervision from the group leader (Giulia Saredi). The project will ideally start in the autumn term, with a recommended length of 60 credits.

If you have any questions on the project, please contact me (g.saredi[at]dundee.ac.uk) and include a brief description of why you’re interested in joining the lab.

January 29, 2025

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Molecular Biology

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Strain-level profiling of antimicrobial-resistant bacteria in metagenomics data for tracking resistance to antibiotics

Abstract

Antimicrobial resistance (AMR) in bacteria—the ability to survive despite the presence of drugs (antimicrobials) designed to kill them or inhibit their growth—is a growing concern worldwide. This resistance makes standard treatments ineffective in humans and animals, leading to persistent infections and the increased spread of resistant pathogens. AMR results from complex interactions between humans, food, animals, and environmental systems. The unit of AMR resistance is the strain, a dynamic entity that can evolve or acquire resistance genes. Despite significant research efforts, gaps remain in understanding how strains acquire AMR, persist, and spread across these interconnected systems, which hampers our ability to model and control AMR effectively. It is also challenging to effectively trace AMR-carrying strains across diverse ecosystems, limiting our capacity to predict the emergence and spread of AMR. In this project, we propose to develop a computational tool to predict the emergence of AMR and trace the transmission and persistence of bacteria carrying AMR at the strain level in different systems using publicly available metagenomics and whole genome sequencing data. Building on the fast-expanding metagenomic databases, we will focus on a key system such as the human, food, animal, soil and water microbiomes. This research will provide much-needed capabilities in source-tracking of AMR-carrying strains and significantly improve the models used to predict and control their spread.

 

Background

Metagenomics, the study of genetic material recovered directly from any type of samples, has revolutionized our ability to study microbial communities, including those that harbour antimicrobial resistance genes (AMR). It allows for the comprehensive analysis of microbial diversity and function without the need for culturing individual organisms. Metagenomics can provide a complete picture of the microbial community structure and the presence of AMR, offering insights into the resistome (the collection of all resistance genes) of a given environment (De Abreu et al., 2021). It enables the discovery of novel resistance genes and mobile genetic elements such as plasmids that could contribute to the spread of AMR and contributed to elucidate the ecological interactions and environmental factors that influence the distribution and abundance of AMR. It also has the potential to reveal and track specific strains carrying AMR. Tracking AMR at the strain level is crucial for understanding the transmission dynamics and persistence of resistant bacteria. Previous traditional methods, such as multilocus sequence typing (MLST) and whole-genome sequencing (WGS), have been employed to track specific strains and for outbreak investigations. However, these methods often rely on the isolation and culturing of bacteria, which can be labour-intensive and limited to cultivable strains. Combined with WGS, metagenomics is a powerful tool to characterize AMR at the community level in a given system. However, metagenomics also has limits. Because it relies on short-read sequencing technologies, it is difficult to assign AMR to specific bacterial strains. Nonetheless, advances in bioinformatics have led to the development of strain-level metagenomics, where algorithms can differentiate between closely related strains within a metagenomics sample (Beghini et al., 2021; Olm et al., 2021). The development of long-reads sequencing, sometimes combined with short-reads sequencing, has also improved the resolution to trace AMR-carrying strains in metagenomics data.

Despite these advances, comprehensive strain-level tracking of AMR in diverse microbiomes (human, food, animal, environmental) remains challenging. Our project aims to address these limitations by developing novel bioinformatics methods and integrating high-quality WGS data with metagenomics to enhance the resolution of strain-level analysis.

 

Specific aims

The specific aims will be the following:

  1. Benchmark the existing tools used for strain-level profiling in metagenomics data
  2. Develop a computational tool to trace bacteria at the strain level from metagenomics and whole-genome sequencing
  3. Validate this tool on a set of metagenomics data and determine the bacteria strain transmission between (and persistence within) samples.

 

Contact

Dr. Ghjuvan Grimaud (Division of Biotechnology and Applied Microbiology)

ghjuvan_micaelu.grimaud@ple.lth.se

 

References

Beghini, F., McIver, L. J., Blanco-Míguez, A., Dubois, L., Asnicar, F., Maharjan, S., … & Segata, N. (2021). Integrating taxonomic, functional, and strain-level profiling of diverse microbial communities with bioBakery 3. elife, 10, e65088.

De Abreu, V. A., Perdigão, J., & Almeida, S. (2021). Metagenomic approaches to analyze antimicrobial resistance: an overview. Frontiers in genetics, 11, 575592.

Olm, M. R., Crits-Christoph, A., Bouma-Gregson, K., Firek, B. A., Morowitz, M. J., & Banfield, J. F. (2021). inStrain profiles population microdiversity from metagenomic data and sensitively detects shared microbial strains. Nature Biotechnology, 39(6), 727-736.

January 29, 2025

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Bioinformatics Molecular Biology

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Comparison of beta-oxidation pathways from different microorganisms to generate medium-chain acyl-coA

Background

Saccharomyces cerevisiae is a widely used microorganism in biotechnology, serving as a cell factory for the production of diverse high-value chemicals. Fatty acid catabolism, particularly β-oxidation, plays a pivotal role in degrading fatty acids and producing acyl-CoA intermediates, which are precursors for numerous valuable compounds (Wang et al., 2024). In S. cerevisiae, β-oxidation occurs exclusively in peroxisomes and is essential for both fatty acid degradation and the metabolic engineering of pathways to accumulate medium-chain acyl-CoAs, precursors for the biosynthesis of high-value chemicals such as capsaicinoids (Muratovska et al., 2022).

Engineering β-oxidation pathways has significant potential to expand substrate specificity and generate a broader diversity of medium-chain acyl-CoAs. This can be achieved by integrating heterologous enzymes with promiscuous substrate specificity or optimized catalytic properties. These tailored acyl-CoAs could subsequently feed into engineered metabolic pathways for novel or improved production of industrially and pharmaceutically relevant compounds.

In this project, we aim to develop a comprehensive database of β-oxidation enzymes from microbial species known to produce medium-chain fatty acids. To achieve this, we will:

  • Identify microbial species known for their β-oxidation capabilities and medium-chain fatty acid production by conducting a literature search, including yeast species closely related to cerevisiae.
  • Download and annotate the genomes of selected species to identify β-oxidation genes to build a database of β-oxidation enzymes.
  • Perform comparative analyses of β-oxidation pathways and enzyme sequences to identify conserved motifs or residues critical for substrate recognition and specificity.
  • Map and compare β-oxidation pathways across species to uncover unique strategies for fatty acid catabolism and identify candidate enzymes for heterologous expression in cerevisiae.

This study will provide insights into the molecular determinants of enzyme specificity and pathway diversity, enabling the rational design of β-oxidation pathways in S. cerevisiae. Ultimately, it will support the engineering of yeast strains capable of efficiently producing medium-chain acyl-CoAs for applications in biotechnology and synthetic biology.

Specific aims

  • Build a database of enzymes involved in β-oxidation for the production of medium-chain fatty acids
  • Perform comparative analysis of the identified enzymes to improve the production of medium-chain acyl-coA.

Contact

Dr. Ghjuvan Grimaud (Division of Biotechnology and Applied Microbiology)

ghjuvan_micaelu.grimaud@ple.lth.se

 

References

Muratovska, N., Silva, P., Pozdniakova, T., Pereira, H., Grey, C., Johansson, B., & Carlquist, M. (2022). Towards engineered yeast as production platform for capsaicinoids. Biotechnology Advances, 59, 107989.

Wang, Z., Su, C., Zhang, Y., Shangguan, S., Wang, R., & Su, J. (2024). Key enzymes involved in the utilization of fatty acids by Saccharomyces cerevisiae: a review. Frontiers in Microbiology, 14, 129418

January 29, 2025

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Bioinformatics Molecular Biology

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Biotechnological production of insect pheromones in plants

Bark beetle outbreaks represent a threat to forests worldwide. Under normal circumstances, they colonize dead or low vigour trees, which promotes nutrient cycling in the ecosystem. However, in large numbers they are capable of colonizing healthy trees, using aggregation pheromones to coordinate these attacks. It has been proven that using pheromone baits as a control strategy to interfere with bark beetle behaviour is effective. Similarly, predators of these beetles are attracted by the presence of the beetles’ pheromones.
As several of these pheromones share the same C5 building block molecules as plant secondary metabolism, in the Van Aken Lab, we have engineered different metabolic pathways to produce insect pheromones from plant metabolism. Having plants producing insect pheromones opens the possibility for using them as natural dispensers of pheromones or as a biofactory for later extraction. Currently in this project, we are engineering alternative enzymes for the current pathways and new cloning strategies for improving the production of these pheromones, as well as new pathways to produce different pheromones.
In this project, we will use several cloning techniques such as Multisite Gateway cloning, Golden Gate cloning and Gibson assembly. We will work with the model organism Arabidopsis thaliana, as well as N. benthamiana and the oilseed crop Camelina sativa. We will use expression analysis via qPCR and GC/MS to evaluate plant metabolite production.
For this project, it is expected to have a student with an interest in plants and molecular biology, as well as biotechnological applications. The start date is flexible, as well as the duration of the project. If you are interested, please contact Olivier Van Aken (olivier.van_aken@biol.lu.se) for more information.

January 27, 2025

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Molecular Biology

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Precision gene therapy for epilepsy

Epilepsy is a family of neurological disorders affecting 1% of the general population. About 30% of patients are resistant to current medications, and surgical treatment options are possible for only a minority of selected cases. Pharmacoresistant patients continue to experience seizures throughout their lifetime, with a severe impact on their quality of life. The development of novel and more effective treatment strategies is therefore highly needed, as well as preventive approaches that could block the progression of the disease.
The main objective of this project is to develop highly specific and precise gene therapy approaches that target critical cell populations involved in the development of epilepsy and seizures. By using a combination of advanced molecular biology, electrophysiological and imaging techniques, we will (i) identify hyper-active neuronal ensembles involved in the early stages of epileptogenesis, (ii) charachterise their location, molecular identity and functional alterations, (iii) apply gene therapy approaches designed to limit the functional output of hyper-active neurons and prevent the development of chronic epilepsy. These approaches will be validated in different animal models of epilepsy, and will provide important new knowledge on the mechanisms of epileptogenesis, as well as basis for the development of preventive treatments that could further be translated in the human condition.
Contact: Marco Ledri (marco.ledri@med.lu.se)
https://portal.research.lu.se/en/organisations/epilepsy-center
https://portal.research.lu.se/en/organisations/molecular-neurophysiology-and-epilepsy-group
https://portal.research.lu.se/en/persons/marco-ledri

January 27, 2025

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Molecular Biology

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