Tsunami – Naturereignis, Naturgefahr, Naturkatastrophe:Schülervorstellungen und wissenschaftliche Vorstellungen zu einem Thema zwischen Physischer Geographie und Humangeographie

According to a constructivist understanding of learning, acquiring knowledge is always based on and directed by subjective conceptions pre-existing in the learner´s head.Against this backdrop, it is rather difficult to understand why the students´ previous ideas are paid comparatively little attention to when it comes to arranging beneficial learning situations - both in school as well as in subject-related didactical research.Following the model of didactic reconstruction this research project aims at examining 7th graders´ pre-concepts about the topic “tsunami” by employing guideline-based and problem-centered interviews which are to be interpret subsequently by means of qualitative content analysis. The study´s declared goal is to arrive at a better understanding of this topic arousing much interest on the students´ part, as it tries to reveal various patters of thought as well as difficulties in comprehension. Among others, one central observation made is that students absolutely have consolidated concepts at their command with regard to tsunami genesis, its impacts and possible preventive measures. These ideas, however, are likely to diverge blatantly from scientific concepts

The serine hydroxymethyltransferase gene glyA in Corynebacterium glutamicum is controlled by GlyR

Serine hydroxymethyltransferase (SHMT) occupies a central position in one-carbon metabolism, and we here study its regulation in Corynebacterium glutamicum. Enzyme quantifications revealed an about 3-fold increase of SHMT activity during exponential growth with a further increase at the onset of the stationary phase. The SHMT encoding glyA gene was shown to be transcribed as a monocistronic mRNA, and its transcriptional start site was determined. Using DNA affinity chromatography the regulator GlyR (Cg0527) was identified and its chromosomal deletion shown to abolish the increase in SHMT activity in the stationary phase. The involvement of GlyR in glyA control was further confirmed by a transcriptional fusion of the glyA promoter with cat and chloramphenicol acetyltransferase quantifications. GlyR was isolated and mutational studies together with electrophoretic mobility shift assays showed that it binds to the imperfect palindromic motif CACT-N(2)-AATG in the -119 to -96 upstream region of the glyA promoter. These and further data illustrate that the essential SHMT has highest activity in the stationary phase and that GlyR acts as an activator of glyA transcription in this growth phase

Reduced folate supply as a key to enhanced L-serine production by Corynebacterium glutamicum.

Stolz M, Peters-Wendisch P, Etterich H, et al. Reduced folate supply as a key to enhanced L-serine production by Corynebacterium glutamicum. Applied Environmental Microbioloy. 2007;73(3):750-755