Climate change meets life’s crunch point – how do heatwaves affect the basic functions of life?

Introduction

Climate change is a reality, and with the steady rise in global temperatures comes a rise in the frequency, duration and severity of heatwaves that is predicted to continue over the course of the century.

There is and increasing general interest in the consequences of heatwaves, however studies have looked almost exclusively at their effects on the physiology of the whole organism or on the migratory behaviour of populations. Hardly any studies have investigated the effects of heatwaves from the single cell level — the stage in which all organisms start out — to the level of multicellular organisation later in the life cycle.

While in mammals and, to a lesser extent, birds, the zygote is protected against the environment by the maternal body, in the vast majority of life forms this is not the case. Here protection is provided in the best cases merely by a shell, making early life stages of almost all other life forms on earth directly vulnerable to the effects of heatwaves.  

In this project we will address the hypothesis that climate change-related extreme heat events have a distinct impact on single cell stages, affecting fundamental processes such as cohesion and communication with other cells at the multicellular level, which is expected to impact organismal and population fitness later in life.

To test this hypothesis, we will use two model organisms from opposite tips of the tree of life: the social amoeba or slime mold Dictyostelium discoideum, and the zebrafish Danio rerio as representatives of different levels of both biological organization and multicellular integration.

 

The zebrafish and the social amoeba are model organisms for Cell Biology and Genetics with sequenced genomes and a large body of knowledge on their molecular mechanisms of action in response to temperature challenges. Both species have well-characterised transitions from single-cell to multi-cell to organism stage

 

In this project you will subject single-cell stages to conditions that simulate heatwaves and will use a combination of modern molecular genetics, cell and developmental biology and behavioural phenotyping to investigate four fundamental aspects:

  1.  The consequences at the single-cell stage (growth, gene expression cell size and morphology)
  2.   The consequences for the multicellular stage (developmental programme at morphology and gene expression levels)
  3. The effects on organismal fitness (fate of the labelled cells in multicellular structures)
  4. The effects on population fitness (efficiency of sporulation and spore germination or swimming assays)

 

This video illustrates very nicely the life cycle of the slime mold. The opportunities to study the effects of heatwaves at single cell and multicellular stages are quite evident. Click on link below:

https://www.youtube.com/watch?v=5h8WOWEqP6o

 

This video is an example of a swimming assay. Fish larvae were previously treated with a specific substance. The larvae are then tapped gently on the head to trigger swimming. Click on link below:

https://drive.google.com/file/d/1E6NJNXQtcaYK_mQkcsqcZxXOlmYyHxYr/view?usp=sharing

 

Entry requirements

We are looking for a motivated student with a keen interest in interdisciplinary research and molecular biology work. You should normally have, or expect to obtain, at least a 2:1 UK Honours degree (or international equivalent) with emphasis in biology, molecular biology, developmental biology or genetics. If you are not sure if you have the relevant background, please feel free to contact the supervisors to discuss the project.

Training and supervision

You will be supervised by Dr. Francisco Rivero from the Hull York Medical School and Dr. Katharina Wollenberg Valero from Biological and Marine Sciences at the University of Hull. Both have an excellent track record in training PhD students and publishing high impact research.

You will join an exciting research and training environment with a multitude of projects related to the molecular basis of climate change stress response and adaptation in various systems. The project will provide you specialist training in molecular and cell biology, image analysis and behavioural analysis. The study will also take advantage of resources available at DictyBase (http://dictybase.org) as well as the zebrafish information network ZFIN (https://zfin.org/) and will benefit from our laboratory facilities as well as in-house High Performance Computer for gene expression analysis. In addition, you will have access to a range of training courses designed to facilitate skills development and will be expected to present the outcomes of this project at both national and international conferences.

Expected outcomes

This project will use molecular and developmental biology tools to address a timely question about the effects the effects of extreme climatic events on vulnerable early developmental stages and the adaptation mechanisms deployed by the cell to mitigate or overcome those extreme conditions. This project will have practical applications in ecology, evolution, environmental genomics and human health.

Background reading

Forbes, G., Schilde, C., Lawal, H., Kin, K., Du, Q., Chen, Z.-H., Rivero, F., P. Schaap, P. 2021. Conservation and change in small GTPases and their regulators throughout dictyostelid evolution. Small GTPases, in press.

Rodríguez, A., Rusciano, T., Hamilton, R., Holmes, L., Jordan, D., Wollenberg Valero K.C. 2017. Genomic and phenotypic signatures of climate adaptation in an Anolis lizard. Ecol Evol. 7:6390-6403.