Graduate Students Mini-Symposium II/2019

Graduate Students Mini-Symposium

  • Date: Aug 26, 2019
  • Time: 13:15
  • Location: MPI for Terrestrial Microbiology
  • Room: Lecture hall
  • Host: IMPRS
  • Contact: imprs@mpi-marburg.mpg.de

Program:

13:15 Sanika Vaidya, AG Drescher

Bacterial cell lysis triggers biofilm formation in Vibrio cholerae

Abstract: The human pathogen Vibrio cholerae must adapt to rapidly changing conditions when it is transmitted between the human host and aquatic environment. In both niches, V. cholerae predominantly exists in matrix-embedded bacterial communities, called biofilms, which help protect cells from various biotic and abiotic stressors. During its lifecycle, it often encounters bacteriophages, biological entities that infect and replicate in bacteria eventually leading to bacterial lysis. In this study, we show that exposure to lytic bacteriophages acts as a trigger for V. cholerae biofilm formation. We discovered that phage-induced lysis acts as the signal for causing biofilm matrix production. Interestingly, we noticed that bacterial lysates generated by other methods also induced biofilm formation in V. cholerae. We hypothesize that V. cholerae cells sense a component of lysed bacteria and employ a defensive biofilm mode-of-life as a general mechanism to combat bactericidal factors.

13:50 Manuel Alejandro González Vera, AG Brune

Polysaccharide Degrading Potential in the Hindgut of Higher Termites

Abstract: The symbiotic digestion of lignocellulose by higher termites involves the cooperation between the activities of the host and its bacterial microbiota housed in enlarged hindgut compartments. Previous studies have shown that the microbiota composition is strongly dependent on the termite host diet. This reflects the differential availability of polysaccharides and suggests distinct carbohydrate-degrading capabilities between the major bacterial lineages. To overcome the difficulty of obtaining bacterial isolates we undertook a in silico approach to evaluate and contrast the carbohydrate-active enzymes profiles of over a hundred metagenome-assembled genomes from the guts of higher termites.

14:25 Iria Bernhardsgruetter, AG Erb

Propionyl-CoA synthase: a dynamic enzyme reactor harboring a sleeping carboxylase function

Abstract: Structural and biochemical analysis of propionyl-CoA synthase (PCS) revealed that the enzyme features a multi-catalytic reaction chamber that catalyzes the three subsequent reactions from 3-hydroxypropionate to propionyl-CoA in a highly coordinated fashion. The last domain, annotated as reductase domain, reduces the intermediate acrylyl-CoA to propionyl-CoA. However, a bioinformatics screen detected a characteristic CO2-binding pocket within the reductase domain, predicting a potential carboxylase activity. Indeed, a low carboxylation yield of 3 % was measured when running the PCS reaction in presence of CO2. The combination of improving CO2-binding and disfavoring the reduction reaction through targeted mutagenesis increased the carboxylation yield to 95 %.

15:00 Andre Sim, AG Fritz

Exploring Bacterial Conserved Gene Neighbourhoods with GenCoDB: the Statistical Genome Conservation Database

Abstract: Conserved gene synteny has proven to be a powerful tool in microbiology, despite this, acquiring statistical data on the strength and taxonomic distribution of gene clusters is not highly accessible. Therefore, we created GenCoDB, a webtool where users can easily perform analysis on the genomic contexts for their genes of interest including co-occurrence analysis, phylogeny comparisons and conservation strength evaluation. Furthermore, using this tool, the evolutionary behavior of gene clusters was analysed and a few interesting cases were further explored highlighting a conserved interplay between many important cellular functions linked by genomic context. GenCoDB is available at www.GenCoDB.org.

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