Soil is a home for an unbelievable diversity and abundance of microbial life that is essential for supporting life on our planet.

How soil microbial composition impacts structure and composition of the aboveground plant and animal communities?

In this thesis, the role of plant-mediated soil legacy effects in shaping aboveground plant-insect interactions was investigated.

Soil biodiversity is of great importance for the maintenance of multifunctionality in terrestrial ecosystems.

The soil ecosystem consists of the largest reservoir of biodiversity on Earth.

The main research question of this thesis was: Can nitrogen cycling on dairy farms on peat soil in the Dutch Green Heart area be improved by adapting management to the nitrogen supply from soil and by using other grassland species and crops without affecting milk production?

Promotor: J.A. van Veen, Co-promotor: E.E. Kuramae

Promotores: Prof.dr. H. van Veen & Prof.dr. W. de Boer (Wageningen University)

By growing in a soil plants change the biotic and abiotic properties of the soil in which they grow.

How presence, abundance and enzymatic activities of AM and EM fungi differently affect soil carbon sequestration processes?

Promotores: J.A.van Veen, P.L.G.Klinkhamer. Co-promotor: E.E.Kuramae

Plants and soils from natural ecosystems harbor great diversity of soil microorganisms, which could potentially contribute to the sustainability of horticulture. The knowledge about using wild plant species and soil from natural ecosystem to improve the crop health will advance the application of ecological…

In this thesis, I focused on studying the above- and belowground interactions of J. vulgaris from a plant-soil feedback (hereafter, PSF) perspective. I investigated the temporal variation of negative PSF and examined the effects of root-associated bacteria on plant performance and aboveground herbiv…

The skin is our natural barrier and lipids are a key part of this barrier. In the outer skin layer, the stratum corneum (SC), lipids form a densely organized structure dependent on the composition of these lipids.

In this PhD study, I aim to deepen our understanding of the influence of major mycorrhizal types, namely arbuscular mycorrhizae (AM) and ectomycorrhizae (EM), on the global soil carbon cycle and their potential distribution changes under future environmental shifts.

The use of N fertilizers has increased worldwide in the past century. While this increased input of N has increased food productivity, it has also contributed to decreases in biodiversity, soil quality and environmental health, including increases in greenhouse gas emissions.

Promotor: Prof.dr. J.A. Bouwstra, Co-promotor: A. El Ghalbzouri

Promotor: J.A. Bouwstra Co-promotor: A. El Ghalbzouri

Vinasse is a major by-product generated by the sugarcane biofuel industry. It is a source of microbes, nutrients and organic matter and often it is recycled as fertilizer.

The stratum corneum is the outermost skin layer and consists of dead cells embedded in a lipid matrix.

The research described in this thesis shows that hypercholesterolemia, a well-established risk factor for atherosclerosis, can impact skin lipid pool and barrier function already at young age. In the field of atherosclerosis, we showed that the small peptide Lyp-1 can be used as a targeting molecule…

The lipids in the uppermost layer of the skin, the stratum corneum (SC), play an important role in the skin barrier function. The three main SC lipid classes are ceramides (CER), cholesterol and free fatty acids.

Striga hermonthica, commonly known as witchweed, infests major cereal crops in Sub-Saharan Africa causing severe yield losses and threatening the livelihood of millions of resource poor farmers.

Promotor: J. A. Bouwstra

Barrier function is the natural role of the skin. The lipid matrix present in the outermost layer of the skin, the stratum corneum is important for this function.

Promotors: Prof.dr. G.R. de Snoo, Prof.dr. G.A. Persoon, Prof.dr.ir. H.H. de Iongh

uman skin equivalents (HSEs) are in vitro 3D-skin models that mimic many aspects of the native human skin (NHS) and can be a valuable tool.

De

Agglomeraties presteren minder goed dan steden met één bestuur. Dat blijkt uit onderzoek van Ton van Raan, professor kwantitatief wetenschapsonderzoek.

What are the global relationships between environmental conditions and abundance of distinct types of mycorrhizal fungi in soil and plant roots?

‘Wat ik aantrekkelijk vind aan het bodemleven, is dat het stuurbaar is,’ verklapt onderzoeker Martijn Bezemer van het Instituut Biologie Leiden (IBL). ‘Dat je kan zeggen: wat wil je? En dat ik de bodem dan kan omtoveren tot iets wat jij nodig hebt. Ten minste, dat dachten we.’

Jan Willem Erisman wilde als kind al dingen beter maken. Als hoogleraar Duurzaamheid en Milieu is hij daarom ook buiten de universiteit actief. Hij staat bekend als de stikstofprofessor: in de media, maar ookin de Tweede Kamer legt hij het stikstofprobleem uit. Recent trad hij toe tot de Europese Soil…

In vergelijking met andere landen zijn de barrières in Nederland om tot inzet van kroongetuigen te komen hoog. Dat concluderen Leidse rechtsgeleerden in het vandaag verschenen onderzoeksrapport ‘Collaboration with Justice in the Netherlands, Germany, Italy and Canada’. Het rapport geeft een unieke inkijk…

Het Liliane Fonds en het Afrika-Studiecentrum van de Universiteit Leiden hebben de Impact Challenge Award 2019 gewonnen voor het project 'Breaking down barriers to exclusion. Building capacity for lobby and advocacy for children with disabilities'. De Impact Challenge Award is een nationale onderscheiding…

Promotor: M. Danhof, Co-promotor: E.C.M. de Lange

Promotor: Prof.dr. W.J.G.M. Peijnenburg

Hans Ulrich Scherer is hoogleraar reumatologie, in het bijzonder translationele reumatologie. Met zijn leerstoel wil hij bruggen slaan tussen onderzoek en kliniek, maar ook tussen afdelingen en organisaties in binnen- en buitenland. Aanstaande vrijdag spreekt Scherer zijn oratie uit. 'Om vooruitgang…

The rapidly increasing commercial application of metallic nanoparticles within products will inevitably enhance the amount of NPs being released into soil.

1. To what extent do metallic NPs added to soil extractions change the activity, abundance, or community composition of microbes? 2. How do the effects of metallic NPs on soil microbes differ from the effects of the ions shedding from corresponding NPs?

How the global distribution of vegetation stands dominated by arbuscular and ectomycorrhizal plants relate to principle aspects of belowground carbon accumulation processes?

Microbiome composition of the spermosphere and the rhizosphere of wild and modern bean accessions grown in an agricultural and a native soil from Colombia was characterized by metagenomics and cultivation-dependent approaches.

Streptomyces are bacteria abundant in soil that participate in diverse and complex interactions. These bacteria are the main producers of the antibiotics we currently use in the clinic.

Promotor: E.F. Smets Co-promotor: J. Geml

Promotor: E.F. Smets, Co-promotor: J. Geml

The soil-dwelling, filamentous bacteria of the genus Streptomyces are renowned for their production of useful secondary metabolites including antibiotics. The work described in this thesis provides new insights on the role and regulation of antibiotic production and resistance in these bacteria.

Promotie

This thesis aimed to investigate the impact of exposure dynamics, relative contributions of ENPs(particle) and ENPs(ion), and dosing regimens on the toxicity of ENPs varying in different physico-chemical properties, on the composition and functioning of soil microbial communities.