We aim to unravel the complex and intertwining regulatory systems that control development and antibiotic production in streptomycetes.

The filamentous bacteria Streptomyces are widespread inhabitants of terrestrial soils.

Actinobacteria are well known for the production of bioactive natural products, many of which have applications in the fields of human, animal and plant health. Subject of this thesis are the anthracyclines, glycosylated aromatic polyketides with potent anticancer activity.

Streptomyces are prolific producers of enzymes and secondary metabolites, including more than 50% of all clinical antibiotics. This makes them highly attractive for medical, biotechnological, and industrial purposes.

Antibiotic-resistant bacteria pose a major health threat. Addressing this challenge requires among others the development of new antibacterial compounds. The research described in this thesis focuses on discovering novel antibiotics from soil bacteria, specifically Streptomyces and Paenibacillus.Despite…

Promotor: Prof.dr. G.P. van Wezel, Co-Promotor: E. Vijgenboom

The ongoing increase in antimicrobial resistance combined with the low discovery of novel antibiotics is a serious threat to our health care.

Streptomyces are filamentous bacteria that produce more than two-thirds of known antibiotics.

Streptomyces present a valuable platform for natural product discovery. Lugdunomycin is a novel angucycline-derived polyketide from Streptomyces sp QL37, with unprecedented skeleton and antimicrobial activity.

Promotor: G.P. van Wezel, Co-promotor: D. Claessen

Promotor: G.P. van Wezel

Actinobacteria are Gram-positive bacteria that have a complex multicellular life cycle and are well known for their ability to produce a wide range of bioactive natural products (NPs).

This thesis examines enzyme domain architecture and engineering to improve the breakdown of lignocellulose and starch, abundant biopolymers crucial for sustainable biofuel and biochemical production. Carbohydrate-active enzymes (CAZymes) facilitate this degradation, but the structural complexity of…

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.

Filamentous Actinobacteria, such as Streptomyces, produce a plethora of chemically diverse bioactive metabolites that have found applications across medicine, agriculture and biotechnology.

The aim of this thesis was to study phage infection in Streptomyces, focused on cell wall-deficient cells. Bacteriophages (or phages in short) attach to the cell wall of bacteria after which they replicate and lyse the host cell.

Streptomyces are multicellular, Gram-positive bacteria in the phylum of actinobacteria which produce a high amount of bioactive natural products of which the expression is tightly coordinated with the life cycle.

We aim to provide new insights relating to the spectacular multi-cellular life cycle of streptomycetes and other actinobacteria.

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…

Daniel Rozen (45), at the IBL since September 2012, uses bacteria in laboratory tests on experimental evolution to study the ecology and genetics of adaptation. His research has applied importance, as it reveals how bacteria may be induced to produce new antibiotics. Last January, Rozen received the…

Leiden PhD candidate Jo-Anne Verschoor discovered that nearly twenty percent of the bacterial strains she studied could degrade plastic, though they needed some encouragement to do so. ‘Bacteria are just like people,’ says Verschoor. Her research was published in the journal Communications Biology,…

Increasing resistance and a lack of new antibiotics are a serious problem for public health. Against this background, Gilles van Wezel of the Institute of Biology Leiden is looking for new medicines. Together with former PhD student Changsheng Wu and colleagues he discovered the special antibiotic lugdunomycin,…

Assistant professor Joost Willemse firmly believes that as a teacher, you’re never done learning. ‘Students ask questions about things you’ve never thought of yourself. Ultimately, that makes you better at your job.’ That’s why he always encourages his students to ask questions. And it’s appreciated:…