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Interview - Lively interactions on the smallest scale

Hitchhiking spores, bacteria propelling themselves towards nutrients and a microbial predator with possibly a sword. Bachelor’s student Flory Olsthoorn studied microbial interactions. ‘The microbial world is rich and varied in its interactions. Understanding them is crucial to expand our knowledge of microbial nature, and in particular gain insight into how pathogens function and move.’

Flory Olsthoorn

Taking on several projects for a bachelor’s thesis seems intense. But Flory’s interest in microbial interactions could not be contained in one. When her projects about investigating the protein’s structure involved some waiting time, she took on another. ‘My supervisor, Alise Muok, and head of the lab, professor Ariane Briegel, supported me to follow my interests and do multiple projects. They encouraged my enthusiasm for science.’

Microbial hitchhiking

Immobile microbes can get a piggyback ride from mobile microbes to get to a more favorable place. As part of her bachelor’s thesis Flory studied this so-called microbial hitchhiking in Streptomyces coelicolor who piggybacked on Bacillus subtilis. Both are found in soil.

‘We studied the impact of microbial hitchhiking on the root system of plants in collaboration with the Dutch vegetable-breeding company Enza Zaden.’ It is known that microbes impact the growth and health of plant. Therefore Enza Zaden coats their seeds not only with nutrients, but also with microbes. They use either Bacillus or Streptomyces. Flory showed that mixing them results in microbial hitchhiking. The research continues to find out whether this mixing improves plant growth.

‘I wasn’t sure whether research was for me. But thanks to this internship I discovered that doing research is exactly what I want to do.’

Other research projects

In another project Flory studied a recently discovered protein in the pathogen Treponema denticola, which can be found in your mouth and can cause gum disease. This protein, which is also found in other pathogenic bacteria, plays a role in chemotaxis. This entails the sensing of a chemical compound by bacteria and their directed motion towards this compound. ‘To enable chemotaxis a cascade of signals occurs inside the microbe. The protein is part of that’, Flory explains. ‘We discovered that without the protein, the bacteria more often have a balloon like shape, which differs from their usual, corkscrew like appearance.’ This balloon like shape is, among others, commonly found in biofilms or dental plaque. ‘This is just the start. A lot is still unknown about this protein.’

Last but not least, Flory verified a publication from the 1980’s about a sword shaped structure which was seen in Ensifer adhearens, which predates on other microbes when there is not enough food. ‘I used a modern, more advanced technique called cryo-electron microscopy and did not find such a structure. It was likely an artifact of the method used in the 1980’s, meaning that it might not exist. Ensifer adhearens probably predates using a more common method.’ Flory enjoyed working independently on this research. ‘Not every bachelor’s student gets that chance.’

Flory Olsthoorn, Biology

Flory’s love for science goes back to her childhood. ‘Both my parents have a background in chemistry. And as a child I visited the my dad’s lab. On the open lab days, we would do small chemistry experiments together. That planted the seed.’ She enjoyed physics, biology and chemistry in school and tries to combine those in her studies. ‘I chose biology in Leiden since the bachelor there includes a lot of time in the lab.’ Flory has now started a master’s in Molecular and Cellular Life Sciences in Utrecht were she combines her three favorite subjects in the master track Biophysics & Molecular Imaging.

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