For those of you who do not know Daan. He is a PhD student in our lab, working on a mathematical theory about optimal metabolism for microbial growth-rate maximisation and its experimental testing. One of the principles underlying his theory is optimal allocation of limited resources for the synthesis of metabolic enzymes. What turns out is that Daan is also an expert in allocating his own limited resources.

Daan is a talented road cyclist. A decade ago he competed with riders who are currently riding the tours of Italy, France and Spain. (I regularly wish I had those skills, but let us not go there.) During multiple day cycling events, which can even last several weeks, it is all about staying fit and focussed, while your body is slowing draining resources, which you cannot readily supplement with food. We call this fatigue. Cyclists learn how to the optimise their balance of performance and fatigue, which is one closely associated with optimal resource allocation. Recently, Daan has added a new resource-allocation trick on his sleeve.

He started duathlon, a run then bike then run event. Duathlon is a growing sport in the Netherlands and highly popular in the USA. It is closely related to triathlon, an Olympic sport. During a run-bike-run it is all about allocation of energy resources. Daan found an optimal way of solving this problem during last weekend’s European Championship (EC), in Vejle (Denmark), by focussing on what he does best.

Daan cycles better than he runs. His strategy during the EC was to save resources during the first run, go as fast as possible on his bike, and then run until he can no longer stand. And what a wise choice this was! After the first run he was amongst the slowest, he was the fastest cyclist and was 5th when crossing the finish line. We congratulate Daan with this major achievement!

For more information about the Vejle EC Duathlon 2018 see this link.

Here you see Daan riding earlier this year when he won the Duathlon in Geluwe (Belgium).

 

Recently two new papers were published:

 

1. Low affinity uniporter carrier proteins can increase net substrate uptake rate by reducing efflux by Evert Bosdriesz, Meike T Wortel, Jurgen R Haanstra, Marijke J Wagner, Pilar Torre Cortés and Bas Teusink
2. Metabolite Depletion Affects Flux Profiling of Cell Lines by Avlant Nilsson, Jurgen R.  Haanstra, Bas Teusink and Jens Nielsen

 

In the first paper we compare and test different hypotheses for the existence of low affinity uniporters, in addition to high-affinity ones. Our new model-driven hypothesis shows that a low affinity glucose transporter would experience less inhibition by intracellular glucose and this would give a higher nett uptake rate. However, due to the intimate link between glucose perception and metabolism, direct experimental proof for this hypothesis remained inconclusive. Still, our theoretical results provide a novel reason for the presence of low-affinity transport system.

In the second paper (a commentary) we show that care should be taken with calculating fluxes from long incubation experiments. Over time, some metabolites deplete and this will affect (calculation of)  fluxes