A conditional marker gene allowing both positive and negative selection in plants

Selectable markers enable transgenic plants or cells to be identified after transformation. They can be divided into positive and negative markers conferring a selective advantage or disadvantage, respectively. We present a marker gene, dao1, encoding D-amino acid oxidase (DAAO, EC 1.4.3.3) that can be used for either positive or negative selection, depending on the substrate. DAAO catalyzes the oxidative deamination of a range of D-amino acids. Selection is based on differences in the toxicity of different D-amino acids and their metabolites to plants. Thus, D-alanine and D-serine are toxic to plants, but are metabolized by DAAO into nontoxic products, whereas D-isoleucine and D-valine have low toxicity, but are metabolized by DAAO into the toxic keto acids 3-methyl-2-oxopentanoate and 3-methyl-2-oxobutanoate, respectively. Hence, both positive and negative selection is possible with the same marker gene. The marker has been successfully established in Arabidopsis thaliana, and proven to be versatile, rapidly yielding unambiguous results, and allowing selection immediately after germination

Klassenspezifische Wahlabstinenz - Spielt das Vertrauen in politische Institutionen eine Rolle?

Hadjar A, Köthemann D. Klassenspezifische Wahlabstinenz - Spielt das Vertrauen in politische Institutionen eine Rolle? KZfSS Kölner Zeitschrift für Soziologie und Sozialpsychologie. 2014;66(1):51-76

„Second order“-Effekte und Determinanten der individuellen Wahlentscheidung bei Landtagswahlen: Eine Analyse des Wahlverhaltens im deutschen Mehrebenensystem

Studies on mid-term elections in multi-level systems show that it is used by the voters to get in on the crucial - punish ruling party level - mostly national. This applies also tend to state elections in the Federal Republic of Germany. With few exceptions, empirical studies to test this relationship using aggregate data. In this paper we argue that on an aggregate level often observable "second-order" effect should be the extent attributable to the individual choice decision, as should have a smaller effect on the choice of participating in the federal government parties "classical" determinants of voting behavior in state elections the greater the distance to the next federal election time. Moreover, it is argued that interest should select oriented gain importance when the result of a state election has a significant impact on the distribution of seats in the Bundesrat. We test these arguments using a data set that includes all state election studies 1985 and 2009. The analyzes show - even if one controls for a "individualization" of voting behavior - no empirical evidence for the expectations at the individual level is not a "second-order" effect nor a federal political penetration of voting behavior in state elections observable