The human body consists of hundreds, perhaps thousands of different types of cells, each with different morphologies and functions, despite having the same genome.

John van Noort

Efficient gene-targeting during meiosis

Biosynthetic gene clusters (BGCs) for natural products are widespread in microbial genomes, and they are rapidly exchanged. This research assesses the factors that control the spread of BGCs and resistance genes in nature. This includes risk assessment for the spread of engineered DNA in nature.

The objective of this study was to investigate the expression and function of GRHL2 in different breast cancer subtypes.

Promotores: T.H.W. Bäck, A. Plaat, Co-promotor: F.J. Verbeek

In this thesis, we used genetically engineered mouse models to identify genes and pathways that are involved in ILC formation and in the development of resistance to FGFR-targeted therapy.

This project aims to assess the risk of spread of antimicrobial resistance genes in the environment derived from currently used synthetic biology approaches in the field of drug discovery.

Promotor: Prof.dr. G.P. van Wezel

Streptomyces bacteria are a valuable source of natural products, many of which are used in the clinic or in biotechnology.

Nucleoid associated proteins maintain the architecture of the bacterial chromosome and regulate gene expression, hinting that their role as transcription factors may involve local three-dimensional chromosome re-modelling.

This thesis describes the functional analysis of the Arabidopsis AHL15 gene.

The bacterial cell wall is a nearly universal structure that offers protection and gives the cell its shape. However, environmental stressors, such as cell wall-targeting antibiotics and hyperosmotic conditions, can induce bacteria to shift to a wall-deficient state. It is unknown whether the lack of…

Which genes are involved in woodiness and associated traits such as drought tolerance, flowering time, stem elongation, life span, and plant herbivory, and how do these gene regulatory pathways overlap?

Promotor: P.J.J. Hooykaas, Co-Promotores: P.B.F. Ouwerkerk, M. Wang

PhD defence

PhD defence

In this Ph.D. thesis, we characterized two novel upstream regulators of JUB1, HB40, and HB22, in Arabidopsis thaliana. In Chapter 2, we described functions of HB40 in modulating growth and development via the regulation of JUB1 and GA inactivation genes GA2OXs.

DNA carries various forms of information. Out of these forms of information the most well-known is classical genetic information.

Harvesting rice from the same field, without planting new rice plants? A discovery may bring this scenario closer. Leiden scientists have discovered a gene that allows annual plants to grow after flowering, instead of dying. Publication on 13 April in Nature Plants.

Plant architecture has distinct forms in different plant species, but also within a species the finalarchitecture of a plant is determined by its gradual development and changes therein induced by environmental conditions during the plant’s life cycle.

My PhD project studies how the temporally sequential Hox gene expression is regulated during head-tail patterning of the frog embryo.

Drug induced organ toxicity is the main problem of the drug development and drug usage in the clinic. The liver and kidneys are the most sensitive organs towards drug induced toxicity.

Master's student Thalia Luden receives an NWO grant for her research proposal about a gene that brings flowering plants back into a growth phase. Companies in floriculture and vegetable seed breeding also contribute to the research.

The experiments described in this thesis employ local lentiviral knockdowns in brain areas of female zebra finches followed by behavioural assays consisting of preference and Go/Nogo tasks.

The way genes are folded determines their activity in our body. Leiden biophysicists are now the first to unravel this structure molecule-by-molecule. Publication on December 1st in Nature’s Scientific Reports.

What is the relation between the experience and the act of exclusion?

Leiden biologists have shown that a gene present in plants, animals and yeasts does play an important role in plants, although for years the gene was considered unimportant. It turns out the gene plays a crucial role in the development of vascular tissue in plants. Publication in Nature Plants on 11…

When and how does social anxiety develop? How can it go astray in some adolescents? How can we help troubled young people to attend school regularly and return to a normal developmental pathway?

Researchers at Leiden University have mapped genes that cause breast cancer cells to migrate. The Leiden toxicologists Professor Bob van de Water, Dr Wies van Roosmalen, Dr Sylvia E. Le Dévédec and colleagues studied 1500 individual genes. They found eight, including the SRPK1 gene, that regulate the…

Which brain cell does what, when Parkinson's disease arises? It won't be long before this jigsaw is solved piece by piece. Ahmed Mahfouz, computational biologist, combines bio-knowledge from Leiden with algorithms from Delft and is getting closer to finding the key.

In a publication in Science, Noam Zelcer from the Division of Biopharmaceutics describes a previously unrecognized pathway to regulate LDL-cholesterol levels. He is also able to modulate this pathway. This opens the possibility for complementing and improving the efficacy of statins: A class of drugs…

Supervisor: P.J.J. Hooykaas Co-Supervisor: R. Offringa

Climate change is a challenge for both current and future generations. New biological resources have to be developed in order to meet the demand for energy as well as the demand for food.

The key question addressed in this family study is whether the psychophysiological and neurocognitive abnormalities often reported in SAD patients are heritable and can thus be found in family members of SAD patients as well. Determination of heritability of these deficiencies is essential for endophenotyping.…

The consequences of social tendencies for the legislation and institutions in the fields of social security, the labor market policy and pension reform are examined in this multdisciplinary research program..

We exploit secondary metabolites of plant to develop pharmaceutical compounds and we genetically modify plant genomes to improve crops.

Salicylic acid (SA) is a plant hormone, which is involved in the defense responses to pathogens and to abiotic stress, and in the regulation of plant growth and development.

Plant-microbe interaction resulted in different physio/chemical responses by host plant and interacting rhizobacteria.

Why does social anxiety increase in adolescence and how does it grow out of control in some adolescents?

PhD student Esmee Koedoot studied the underlying processes responsible for metastases in a dangerous type of breast cancer. She hopes to find new possibilities to fight the disease. In December 2019 she obtained her doctorate cum laude.

This project aims at studying the social media reception of African publications as covered by the most important “altmetric” sources.

This thesis, conducted in the framework of ERC Starting grant project BABYLON (PI: Caroline Waerzeggers), presents an investigation into Babylonian society, focusing on the city of Borsippa during Neo-Babylonian and early Persian rule (c. 620-484 BCE).

This dissertation takes an important step in understanding the phenomenon of non-take-up of social support and what it means for contemporary social policies.

In populations with a seed-bank, individuals can temporarily become dormant and refrain from reproduction until they can become active again. The repository of all dormant individuals in the population is called the seed-bank. Seed-banks are observed in many taxa, including plants, bacteria and other…

Genes are active sometimes, and other times they remain dormant for a while. Leiden physicist John van Noort receives an NWO ECHO grant to find out how this happens.

Some people are predisposed to develop cancer. Mutations in genetic material that increase a person’s chances of developing cancer can already be present at birth. Researchers are closely examining these mutations to learn more about how cancer begins to develop.

‘It was a discovery we did not expect,’ says Remko Offringa, professor of Plant developmental genetics. Today he publishes a new trait of a versatile gene in Current Biology: it makes the difference in plants between herbaceous and woody stem growth. A useful feature to prevent dehydration.

Why do some children confront social challenges with confidence, whereas others experience difficulties? What is the role of child temperament and child emotional dispositions? What is the role of parenting? This project aims to shed light on the mechanisms explaining shyness and confidence in response…