Stress-induced evolution (→SIE) of fish and marine invertebrates
We investigate the role of stress-induced variation on molecular phenotypes (proteomes) and the consequences of such variation for evolution. Salinity/ osmotic stress is of particular interest. To dissect and understand the rules that govern SIE we use biological mass spectrometry, targeted proteomics (Skyline and PanoramaWeb), integrative systems/ network modeling, imaging, and synthetic biology approaches (→Proteomics repository).
Key questions that interest us are What is the role of stress-induced evolution (SIE) for biodiversity? What are the underlying molecular mechanisms of SIE? How do cells and species evolve in stressful environments?
The concept of SIE is based on the realization that macromolecular damage is the common denominator of cellular stress (Kültz, 2005). SIE is also known as stress-induced evolutionary innovation (Wagner et al., 2019). It represents an exciting, recently discovered mechanism of evolution, which mechanistically explains biological phenomena that reach beyond the theoretical framework of the Modern synthesis of Neo-Darwinism (Heng, 2019).
Osmosensing and environmental adaptation of euryhaline cichlids
Tilapia are African cichlids that represent a classical model for evolutionary biology. They have radiated into many different ecological niches forming almost 2000 species within a relatively short time. We study several tilapia species that have evolved extreme salinity and pH tolerance and compare them to congeners that have much lower tolerances. The emphasis is on discovering, understanding, and manipulating mechanisms of osmosensing that control gene expression patterns, proteome dynamics, and organismal phenotypes in changing environmental contexts.
Salinity, pH, and temperature are key environmental parameters that impose significant stress on aquatic organisms due to anthropogenic acceleration of climate change. Therefore, our research helps in understanding and predicting consequences of climate change on fish populations and species diversity. By focusing on stress-induced evolution, we aim to better understand the time frame in which evolution can occur and whether the rate of evolution differs in eury- vs. steno-topic species.
After carps, tilapias are the second most important group of aquaculture fish worldwide. Many tilapias are highly environmentally stress tolerant with the exception of cold tolerance. We are interested in how tilapia cold and heat tolerance are genetically determined and how these traits interact with other traits that are important for aquaculture (growth, salinity tolerance, etc.). Photo by Kevin Bauman (CC0 1.0).
Stress-induced evolution of the marine tunicate Botryllus schlosseri
The research investigates how cells from the marine colonial tunicate Botryllus schlosseri evolve when critical molecular networks that control cell growth and programmed cell death are disturbed by either stress or genetic manipulation or a combination thereof. The main question addressed is: What molecular mechanisms constrain cell immortalization?
Immortal cell lines of marine invertebrates have great potential as “bioreactors” for producing pharmaceutical compounds with health benefits, nutraceuticals, anticancer drugs, and other biologically active chemicals. Potential applications of marine invertebrate cell lines also include the production of natural pearls and other jewelry without the need to farm animals. The tunicate B. schlosseri is widely distributed throughout the world and used as a common sentinel species for assessing marine pollution and other anthropogenic impacts on coastal ecosystems. The research contributes molecular tools that increases the utility of this tunicate for bioindication.
Primary cultures of B. schlosseri hemocytes and epithelial monolayers are exposed to (1) environmental factors (media supplements and attachment substrates), (2) stress-induced evolution, and (3) synthetic manipulation of pro- and anti-proliferative genes to increase heritable variation in proteome networks and cellular phenotypes that natural selection can act on. The goal is to understand the sequence of molecular events that promotes cell proliferation and inhibits senescence in vitro. Photo by Massimiliano de Martino (CC0 1.0)