Katherine M. Pappas

Katherine M. Pappas obtained her BSc degree in Biology and PhD in Genetics at the National & Kapodistrian University of Athens (NKUA). She did her postdoctoral studies at the Department of Microbiology, College of Agriculture & Life Sciences, Cornell University. She is currently Assistant Professor of Molecular Microbial Genetics in the Department of Genetics & Biotechnology, Faculty of Biology, NKUA. Her research interests lie in the fields of genomics, transcriptional regulation, cell-cell signaling, plasmid biology, and strain engineering. She has mostly worked with model biotechnological organisms such as Agrobacterium tumefaciens, a plant pathogen and a transgenic technology vector, and Zymomonas mobilis, a bioethanol producer. Her work with Agrobacterium tumefaciens contributed to the understanding of the molecular mechanisms underlying quorum-sensing dependent activation of Ti plasmid replication, a phenomenon with ecological repercussions now thought to characterize other proteobacterial plasmids as well (Nature 417: 971-974; Nature Reviews Microbiology 10: 755-765). Work with Zymomonas mobilis has been multi-faceted and addresses important aspects of the organism’s biology and applicability, not least of which, ‘omics’ aspects (Nature Biotechnology 27: 893-894). Apart from conducting own research, K. M. Pappas reviews for many journals and has also served as Senate member in NKUA, consultant for the Greek Ministries of Health and Education, proposal and institutional evaluator for Greek, EU and British authorities, as well as international mentor and country ambassador for the American Society of Microbiology. 

From tequila shots to chassis genomics: works and days of an ethanol producer

Zymomonas mobilis is a bacterium long known to be involved in the production of alcoholic beverages in the tropics. However, when tested in the laboratory, it is also found to outcompete yeasts in ethanol fermentations. Given the global mandate for cleaner, safer and renewable energy, Z. mobilis has been studied in academic and industrial establishments as a platform catalyst for first and second generation bioethanol. Of interest to my laboratory has been the understanding of the Z. mobilis genome to a comparative, structural and functional level. This helps in discriminating essential from accessory genes, observing genomic division between the chromosome and extrachromosomal elements, gaining evidence for gene flows and horizontal transfer events, and ultimately choosing the most suitable modules – genes or cis-acting elements – in order to enhance the bacterium’s performance. Gene networks that act in cell-cell signaling and mutagenic stress are also of interest, since they reveal important facets of the organism’s physiology. Particularly in terms of elucidating responses that follow mutational challenge, transcriptional profiling has been carried out and has revealed the vast numbers of genes being implicated in SOS induction, in DNA repair and cell-cycle regulation, and in multitudes of other activities expected or unforeseen. Transcriptomics also reveal growth-dependent gene expression variability, which reflects the ways and needs of the organism at different fermentation regimes. Overall, we believe that addressing the organism’s fundamental biology is the first step towards doing insightful engineering and producing novel strains.