Background Ustilago maydis is known for its natural potential to produce a broad range of valuable chemicals, such as itaconate, from both industrial carbon waste streams and renewable biomass. Production of itaconate, and many other secondary metabolites, is induced by nitrogen limitation in U. maydis. The clustered genes responsible for itaconate production have recently been identified, enabling the development of new expression tools that are compatible with biotechnological processes.ResultsHere we report on the investigation of two of the native promoters, Ptad1 and Pmtt1, from the itaconate cluster of U. maydis MB215. For both promoters the specific activation upon nitrogen limitation, which is known to be the trigger for itaconate production in Ustilago, could be demonstrated by gfp expression. The promoters cover a broad range of expression levels, especially when combined with the possibility to create single- and multicopy construct integration events. In addition, these reporter constructs enable a functional characterization of gene induction patterns associated with itaconate production.ConclusionsThe promoters are well suited to induce gene expression in response to nitrogen limitation, coupled to the itaconate production phase, which contributes towards the further improvement of organic acid production with Ustilago.

Primary school teachers need adequate professional knowledge and motivational orientations to qualify scientifically and technologically literate students. Previous studies have focused on the impact of coursework on (pre-service) primary teachers’ content knowledge, rather than on the development of academic self-concepts. In addition, the influence of the course format and the major field of study has not been investigated much to this date. Thus, this study examines the effects of an interdisciplinary course on pre-service primary teachers’ content knowledge and academic self-concepts in science and technology using a quasi-experimental, quantitative, pre-post-follow-up design (n = 202). Whilst no significant changes in knowledge were revealed for the baseline group not participating in the course, significant short-term and long-term cognitive gains were found for the experimental group. Biology-, chemistry-, physics- and technology-related self-concepts increased significantly when participating in the course. The results also indicate that the course format and major field of study can have an impact on the development of pre-service teachers’ professional knowledge. Regarding the development of academic self-concepts in the experimental group, it can be assumed that both the weekly and block course format are beneficial for heterogeneous learner groups consisting of pre-service teachers with different major fields of study.

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Primary school students often do not have differentiated conceptions of human organs and organ systems. As understanding the inner structure of the human body is an elementary prerequisite for the development of health awareness, appropriate forms of teaching must be developed to modify students’ fragmented preconceptions about the inside of their bodies into scientifically accurate concepts. Anatomical models are considered a medium to raise awareness of organs and their systemic integration; however, only a few studies have investigated their effectiveness in the context of primary school. This intervention study, therefore, examines the effect of anatomical models on the conceptions of inner organs in German primary school students (N = 45) in a pretest, posttest, and follow-up test design with anatomy teaching between pre- and posttests. Concepts were measured using students' drawings in two treatment groups (anatomical models versus anatomical illustrations). While in both treatment groups students' conceptions changed toward more scientific concepts, there was little difference in the changes between the two groups. There were even indications that the students of the control group showed more pronounced increases, for example, in long-term systemic integration of the organs. We discuss the reasons for this and furnish recommendations for effective teaching practices.

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