Graduate Students Mini Symposium I 2020

  • Date: Feb 3, 2020
  • Time: 13:00
  • Location: MPI for Terrestrial Microbiology
  • Room: Lecture hall
  • Host: IMPRS
  • Contact: imprs@mpi-marburg.mpg.de

Program:


13:00 Viktoria Reithofer (AG Essen)

Structural analysis of the putative adhesins Awp1 and Awp3 from Candida glabrata, representatives of the Hpf-family

The yeast Candida glabrata is one of the most common causes of candidiasis in humans, although it is more closely related to baker's yeast than to other Candida species. Its ability to adhere to a wide variety of surfaces – mediated by a remarkably large number of adhesins – is regarded as an important pathogenicity factor. Here we present the structural analysis of two putative C. glabrata adhesins, Awp1 and Awp3. Their structures show a high similarity to pectate lyase, but lack an active site. A sequence similarity network identifies both proteins as members of the haze protective factor family.

13:30 Marc Abella Guerra (AG Skruzny)

Mechanobiology of endocytic vesicle formation analyzed by Sla2 force sensors

Clathrin-mediated endocytosis is the principal membrane trafficking route, by which a small region of the membrane reshapes into a vesicle. This requires mechanical force provided by endocytic proteins and actin polymerization. We aimed to measure this force in vivo by FRET-based tension sensors and determined a force of 400-1200 pN per endocytic event. We also analyzed the role of endocytic factors and environmental conditions in force-dependent steps of endocytosis. We found that force requirements can be reduced by mitigating turgor pressure or membrane tension. Our results provide critical values for understanding mechanics of endocytosis and potentially other cellular membrane remodeling processes.

14:00 Thorben Schramm (AG Link)

Temperature-sensitive argininosuccinate synthetase for the dynamic control of citrulline overproducing E. coli

Controlling the metabolism of microbes in a dynamic way is important during bioprocesses. Here, we used temperature-sensitive argininosuccinate synthetase (ArgG) variants to dynamically control citrulline overproducing Escherichia coli. First, we enriched temperature-sensitive ArgG variants in high-throughput by fluorescence-activated cell sorting. Then, we probed single variants for the use as dynamic metabolic valves in a citrulline overproduction strain. With the best variant, we produced 3 g/L citrulline in a 1 L-bioreactor following a process strategy that had a 33°C growth phase and a 39°C production phase.

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