Using an optimized transformation protocol we have studied the possible interactions between transforming plasmid DNA and the Hansenula polymorpha genome. Plasmids consisting only of a pBR322 replicon, an antibiotic resistance marker for Escherichia coli and the Saccharomyces cerevisiae LEU2 gene were shown to replicate autonomously in the yeast at an approximate copy number of 6 (copies per genome equivalent). This autonomous behaviour is probably due to an H. polymorpha replicon-like sequence present on the S. cerevisiae LEU2 gene fragment. Plasmids replicated as multimers consisting of monomers connected in a head-to-tail configuration. Two out of nine transformants analysed appeared to contain plasmid multimers in which one of the monomers contained a deletion. Plasmids containing internal or flanking regions of the genomic alcohol oxidase gene were shown to integrate by homologous single or double cross-over recombination. Both single- and multi-copy (two or three) tandem integrations were observed. Targeted integration occurred in 1-22% of the cases and was only observed with plasmids linearized within the genomic sequences, indicating that homologous linear ends are recombinogenic in H. polymorpha. In the cases in which no targeted integration occurred, double-strand breaks were efficiently repaired in a homology-independent way. Repair of double-strand breaks was precise in 50-68% of the cases. Linearization within homologous as well as nonhomologous plasmid regions stimulated transformation frequencies up to 15-fold.
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Publicatie bij de rede, uitgesproken bij de aanvaarding van het ambt als lector Green Biotechnology aan Hogeschool Inholland te Amsterdam op 20 mei2015 door dr. C.M. Kreike
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What options are open for peoplecitizens, politicians, and other nonscientiststo become actively involved in and anticipate new directions in the life sciences? In addressing this question, this article focuses on the start of the Human Genome Project (1985-1990). By contrasting various models of democracy (liberal, republican, deliberative), I examine the democratic potential the models provide for citizens' involvement in setting priorities and funding patterns related to big science projects. To enhance the democratizing of big science projects and give citizens opportunities to reflect, anticipate, and negotiate on newdirections in science and technology at a global level, liberal democracy with its national scope and representative structure does not suffice. Although republican (communicative) and deliberative (associative) democracy models meet the need for greater citizen involvement, the ways to achieve the ideal at a global level still remain to be developed.
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