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Doctoral dissertation in biology: Genetic modification of the bacterium Rhodothermus marinus

On Monday 27 September, an employee of Matís will, Snædís Huld Björnsdóttir, defend his doctoral dissertation “Genetic changes in the bacterium Rhodothermus marinus“(E. Genetic engineering of Rhodothermus marinus).

Supervisors were Guðmundur Eggertsson Professor Emeritus and Ólafur S. Andrésson professor. In addition, Dr. Jakob K. Kristjánsson CEO of Arkea, Sigríður H. Þorbjarnardóttir expert at the Institute of Biology and Dr. Ólafur H. Friðjónsson, project manager at Matís. 

Opponents are Daniel Prieur, Professor at the Université de Bretagne Occidentale in Brest, France and Dr. Valgerður Andrésdóttir, scientist at the University of Iceland Laboratory of Pathology at Keldur.

Snædís was born in 1973. She has worked at the Institute of Biology, at Prokaria and as a specialist at Matís 'Department of Biotechnology and Biochemistry since 2007. Snædís' research focused on the development of methods to genetically modify the thermophilic bacterium. Rhodothermus marinus. Snædís 'husband is Ægir Þór Þórsson, a horticultural consultant at the Icelandic Farmers' Association. 

Vice President of the Faculty of Life and Environmental Sciences, Karl Benediktsson professor, presides over the ceremony requested The main hall of the main building and starts at 13:00.

Abstract
Rhodothermus marinus is an aerobic, thermophilic bacterium that was first isolated from underwater hot springs at Ísafjarðardjúp. The species is interesting, partly because of its position in the bacterial classification system and because of its adaptation to its natural environment. In addition produces R. marinus a large collection of heat-resistant enzymes that can be used in industry. These include enzymes that break down polysaccharides and biomass. Here's another one Rhodothermus type described. It was isolated from a depth of 2634 m in the Pacific Ocean and was named R. profundi. 

The main objective of this project was the development of methods for genetic modification R. marinus. A method was invented to transfer foreign genes into the bacterium. Two options were used, trpB and purA, but they list for enzymes involved in the synthesis of tryptophan and adenine.  R. marinus a strain that did not appear to have curvature activity was selected for genetic uptake. Both trpB and purA were removed from the chromosome of the receiving strain and therefore both substitutes can be selected. The precipitates prevent rearrangement between the valgenes and the chromosome and the formation of spontaneous Trp+ and Ade+ reversals. 

A small plexiglass, pRM21, was isolated from R. marinus and sequentially. It consists of 2935 base pairs and its largest reading frame records for proteins that correspond to the replication proteins of large plasmids of the IncW family. The plasmid was used in genetic engineering experiments. A good transformation was obtained by electrolyzing the bacterium. The plasmid was also used as a basis for the construction of shuttle boats that replicate both R. marinus and Escherichia coli.  Ferries were constructed for the expression of foreign genes in R. marinus and increased protein production was obtained by using thermodynamic control sequences. Vices that also make it possible to study expression were also found R. marinus and its stewards.

Methods for inactivating genes in the genome were developed R. marinus, both by random and targeted mutations. Genes were deleted from the bacterium chromosome without leaving any foreign sequences. Chromosome genes were also successfully replaced by double rearrangement by linear molecules. Induction of genetic modification R. marinus opens up the possibility of research into its properties as well as utilization. Such methods are even more important now than before since the sequencing of the genome R. marinus was recently published.

Starts: 27/09/2010 - 13:00
Location: Main building
Further location: Celebration hall

EN