Universiteit Leiden

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This Week’s Discoveries | 15 May 2018

Tuesday 15 May 2018
Niels Bohrweg 2
2333 CA Leiden

First Lecture

Witnessing the assembly of a galaxy 800 million years after the Big Bang

Jorryt Matthee (Leiden Observatory)
Jorryt is a Huygens PhD fellow at Leiden Observatory. He investigates the origin and evolution of galaxies by combining observations with the largest telescopes and by analysing state-of-the-art computer simulations.

To learn about the early production of light in the Universe, our best bet is to study in detail the earliest luminous galaxies. One ideal target is the galaxy COSMOS Redshift 7, known as CR7 for short.

CR7 is one of the oldest, most distant galaxies known, observed when the Universe had only ~6% of its current age and it will likely evolve into a massive galaxy cluster like the Coma cluster. Its discovery in 2015 — and subsequent observations of bright clumps of UV emission within it — have led to broad speculations. Does this galaxy host a forming supermassive black hole? Or could it perhaps contain the long-theorized first generation of metal-free stars? To understand the nature of CR7, we need to explore its gas and dust in detail — a challenging task given the distance to this galaxy. However, as I will show, important progress can be made using the capabilities of the new Atacama Large Millimetre Array in Chile.

Second Lecture

The mathematics of blood vessel growth: predicting multicellular patterning from individual cell behavior

Roeland Merks (CWI and MI)

Roeland is a part-time professor of Mathematical Biology at the Mathematical Institute (MI) in Leiden and senior researcher at Centrum Wiskunde & Informatica (CWI) in Amsterdam. His research focuses on the mathematical modeling of multicellular biological systems, including plant development, the gut microbiota, and the development of blood vessels (angiogenesis). He recently received a Vici grant to look for new ways to fix the messy and leaky blood vessels in tumours. To do so, he will combine mathematical simulations and lab experiments.

Tackling messy blood vessels to fight cancer

To create a new blood vessel, the behavior of the building blocks of blood vessels, the endothelial cells, must be coordinated. Apart from molecular cell-cell signaling, endothelial cells exchange mechanical signals to coordinate their behavior. To get a better understanding of such mechanical cell-cell communication, we are developing dynamical mathematical models of cells and the extracellular matrix (ECM). I will discuss how these models help us explain the response of individual cells to the mechanics of the ECM, as well as the collective behavior of cells during angiogenesis. Recently, detailed measurements and new mathematical models of the kinetics of focal adhesions (the macromolecular mechanosensitive assemblies by which cells interact with the ECM) have become available. In our ongoing work we are including these kinetic descriptions of focal adhesions in our models. I will sketch how this approach allows us to mechanistically predict changes in cell shape and in collective cell behavior from changes in focal adhesion kinetics, e.g., due to  genetic knockouts or pharmacological treatment. Altogether, our models help explain how local, mechanical cell-ECM interactions assist in coordinating cell behavior during multicellular patterning.

This Week's Discoveries

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