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Organization of bacterial cells and genomes
Divided bacterial genomes and their potential in synthetic biology
About 10% of the bacterial species represented in genome databases carry their genomic information divided on several replicons, i.e., have multipartite genomes. In addition to the main chromosome, these bacteria harbor one or more large secondary replicons (secondary chromosomes, chromids, or megaplasmids). Several bacteria with segmented genomes are of increasing interest to sustainable industrial biotechnology (e.g., Methylorubrum extorquens, Sinorhizobium meliloti / Ensifer meliloti, and Vibrio natriegens).
Research aims:
- Discover and understand fundamental molecular mechanisms of coordinated replication and segregation of the genomic DNA of multipartite genomes
Bacterial cell polarization and growth
In all three kingdoms of life, cell polarization is a dynamic phenomenon characterized by active accumulation or confinement of proteins within a part of the cell, resulting in their asymmetric distribution and formation of molecule gradients. Binary fission of bacterial cells itself is a source of asymmetry, and polarized chromosome segregation and unipolar cell wall growth are striking examples of bacterial cell polarity.
Implicit in bacterial cell growth is an increase in cell volume and surface, involving expansion of the peptidoglycan sacculus. Insertion of new material into the existing mesh is mediated by tightly controlled peptidoglycan hydrolysis, synthesis, and maturation enzymes. Cell elongation of most rod-shaped bacteria takes place in a dispersed manner along the sidewall, while bipolar and unipolar cell elongation are underrepresented growth modes. Several members of the alphaproteobacterial Hyphomicrobiales, such as Sinorhizobium meliloti, Brucella abortus, Agrobacterium fabrum (A. tumefaciens), and Methylobacterium extorquens, show unipolar cell growth.
Research aims:
- Discover and understand fundamental molecular mechanisms generating cell polarization
- Understand how the cell sets the polar growth zone for unipolar cell elongation
- Understand how replication and segregation of the genomic DNA is coordinated with cell growth and cell division, focusing on unipolarly growing Alphaproteobacteria