The Symposium Programme

All talks during the day will be held at the Van Steenis Building (Einsteinweg 2, Leiden). In the evening we move to the FooBar in the Snellius building (Niels Bohrweg 1, Leiden). If you click on the name of a speaker, an exerpt of the abstract shows up, so you can get a sense of what to expect on the day of the symposium.

Van Steenis E001 E001 F104
9:45 Welcome & Breakfast

Metabolites are small chemical molecules that play many important roles in living organisms. The field of Metabolomics aims to detect, identify and quantify them in order to solve biological questions. These questions can arise in many different fields, such as medicine and quality assessments of foods or environmental areas. This lecture will present some of these applications, but will focus on the challenges in analysing these data, obtained by complicated data-processing pipelines, and highly multidimensional in nature. A common question, for instance, is to indicate differences between two groups of samples, one control group and one treatment group (maybe corresponding... Read more

11:00-11:15 Coffee break

A central topic in plant breeding and genetics is the study of genotype by environment interaction (GxE). GxE occurs when differences in performance (phenotype) between plants with different genetic constitutions (genotypes) are a function of the environmental conditions. Modelling of GxE is relevant for insight in adaptation. Climate change forces plants to adapt to higher temperatures and drought. Plant breeders and geneticists try to identify the genetic factors underlying adaptation. For the modelling of GxE various classes of statistical models have been proposed. A classic approach to GxE describes it by a joint regression of a sample of genotypes on... Read more

Nanotechnology has great prospects of advancing technical capabilities to levels that go far beyond the technology of today. We can learn from Nature that machines at the scale of molecules can, in principle, be produced. Actualy assembling useful machines is still a formidable challenge. However, important steps have already been taken, and research requires the integration of many disciplines: physics, chemistry, materials science, biology, information science, and more. I will present a few examples of experiments and techniques that have been developed, although this account will be colored by the perspective of my own research work. This will show that... Read more

12:00-12:15 Coffee break

Since plants are sessile organisms, they can not displace themselves and have to make do with the environment they find themselves in. As a consequence, the ability to sense and adaptively respond to environmental conditions is of critical importance to the survival of plants. These responses involve all kinds of different decisions, in which direction a plant organ (leaf, root) should grow, where new organs should be formed, when flowers should be formed. In this lecture, I will illustrate how plants count and memorize signals, keep time, and integrate local and long distance signals for their decision making. Furthermore, I... Read more

DNA molecules contain a second layer of information on top of the classical genetic information. This second layer is geometrical/mechanical in nature and guides the folding of DNA molecules inside cells. With the help of a new Monte Carlo technique, Mutation Monte Carlo, and of graph theory we demonstrate that the degeneracy of the genetic code allows for multiplexing of the two information layers. We specifically show that mechanical cues on the DNA molecule can place nucleosomes (DNA-wrapped protein cylinders) with single base-pair resolution anywhere on the genome of baker’s yeast. This suggests that there is plenty of space for... Read more

13:00-13:30 Lunch

Microbes such as bacteria and yeasts actively optimise their cellular growth rate by tuning concentrations of catalytic enzymes and ribosomes. They are able to switch metabolism to accomodate changes in food substrates, mount stress responses, and even shut down the entire cell and go in growth arrest when the need arises. They do all this without having direct knowledge of changes in the environment such as the availability of food sources. In this talk I will present a general theory how cells might be able to solve this conundrum, and how they might implement this using biological mechanisms such as... Read more


Our genome is organized in long strings of nucleosomes, consisting of about 150 base pairs of DNA and 8 histone proteins, which are spaced by 10-80 base pairs of linker DNA. Strings of nucleosomes further fold into dense chromatin fibres. The structure of these fibres has remained largely obscure because both high-resolution structural techniques like NMR, electron microscopy and X-ray crystallography and optical (super-resolution) microscopy techniques can hardly resolve the path of the DNA in such fibres. However, exciting new progress has been reported in the field, and the contours of a physical understanding of chromatin structure and dynamics are... Read more

“The field is continuously fascinating. In fact, I’ve often thought a good title for either a book or a lecture about immunology would be Endless Fascination” Dr William Erwin Paul (2012) The immune system of plants and animals is very complex and we are still in the very beginning of understanding this complexity. Every small step we take in this direction leaves us once more fascinated with the efficiency, and preciseness of the system. In my lecture I will first explain what is often known as the main function of the immune system: discriminating self (harmless) from non-self (dangerous). The... Read more

15:00-15:15 Coffee break

To survive, all living cells must be able to perceive changes in their environment and adapt accordingly. Proteins play an essential role in these processes by reacting to environmental changes and forming networks to pass on signals to other cellular machinery. Sensor proteins change conformation upon receiving a specific trigger. These changes are then propagated and amplified by networks of interacting proteins. Studying the intricate changes in signal transduction networks requires high resolution in both time and space, as highlighted by two examples. Starting at the very beginning of a signal transduction network, i.e. the actual perception, the molecular mechanisms... Read more

Compared to for example economists, evolutionary biologists are in the lucky situation that they can base themselves on a good microscopic mechanism: individuals reproduce almost, but not totally faithfully. Define the environment as anything outside an individual that impinges on its behaviour, now or in the future, and a population as a collection of individuals sharing the same environment. In that case we can use the frequency distribution of individuals over their physiological states as population state. If the number of individuals is sufficiently large the population process becomes deterministic. If the environment is given as a function of time... Read more

16:00-16:15 Coffee break

ORTEC is one of the world’s leaders in optimization- and analytics solutions. We provide companies in a wide range of industries with the insights to become more efficient, more predictable and more effective. During this lecture you will not only learn more about ORTEC as a company, but also about... Read more

Snellius building FooBar
17:00-......... Dinner & Drinks