Lehr- und Lernvorstellungen angehender Biologielehrender im Kontext des Praxissemesters

ZUSAMMENFASSUNGLehr- und Lernvorstellungen (LLV) konstituieren u. a. das Lehrerprofessionswissen. Die naturwissenschaftliche, universitäre Lehramtsausbildung ist v.a. durch konstruktivistische Paradigmen geprägt. An Schulen finden sich vielfach eher transmissive LLV. Praxisphasen innerhalb der Lehramtsausbildung könnten voruniversitäre transmissive LLV der Lehrkräfte stärken. An der Universität Bielefeld wird das gerade eingeführte halbjährige Praxissemester stark mit Elementen Forschenden Lernens verknüpft. In der vorliegenden Studie interessierte, ob diese Elemente die Ausprägung der Zustimmung zu den LLV zwischen den Gruppen vor und nach dem Praxissemester beeinflussen. 105 Studierende (MAlter = 24.90 Jahre, SDAlter = 2.07 Jahre, 73,30 % weiblich) des Fachs Biologie wurden bezüglich der Wirkung des Praxissemesters auf ihre generalisierten LLV transmissiv und konstruktivistisch sowie ihre fachspezifischen LLV zu Vernetzung und Präkonzepten im Fach Biologie untersucht. Die Ergebnisse dieser Trendstudie zeigen eine überraschende Wirkung des Praxissemesters: Transmissive LLV sind nach dem Praxissemester besonders gering ausgeprägt. Möglicherweise könnte dies auf eine gelingende Theorie-Praxis-Verknüpfung zurückzuführen sein.ABSTRACTTeacher beliefs about learning constitute i. a. professional competence in teaching. The science teacher training at university is characterized by constructivist paradigms in particular. Most often, teacher beliefs at school are transmissive. Practical phases during teacher training at university could strengthen the teacher trainees’ pre-university transmissive beliefs. The currently established six-month practical semester at the Bielefeld University is strongly linked to elements of research-based learning. The present study investigated if these elements of theoretical reflection influence the consent to the beliefs between the groups before and after the practical phase. Therefore, the effects of the practical phase on the general beliefs about transmissive and constructivist learning as well as the science-specific beliefs about connectivity and preconcepts in biology of 105 teacher trainees (MAge = 24.90 years, SDAge = 2.07 years, 73,30 % female) were examined. Results of the trend study hint that the practical phase had a surprising effect: Transmissive beliefs are remarkably weak after the practical phase. This may be ascribed to a successful conjunction of theory and practice

Analysis of connexin 43, connexin 45 and N-cadherin in the human sertoli cell line FS1 and the human seminoma-like cell line TCam-2 in comparison with human testicular biopsies

Background: Germ cell tumors are relatively common in young men. They derive from a non-invasive precursor, called germ cell neoplasia in situ, but the exact pathogenesis is still unknown. Thus, further understanding provides the basis for diagnostics, prognostics and therapy and is therefore paramount. A recently developed cell culture model consisting of human FS1 Sertoli cells and human TCam-2 seminoma-like cells offers new opportunities for research on seminoma. Since junctional proteins within the seminiferous epithelium are involved in cell organization, differentiation and proliferation, they represent interesting candidates for investigations on intercellular adhesion and communication in context with neoplastic progression. Methods: FS1 and TCam-2 cells were characterized regarding gap-junction-related connexin 43 (Cx43) and connexin 45 (Cx45), and adherens-junction-related N-cadherin using microarray, PCR, Western blot, immunocytochemistry and immunofluorescence. Results were compared to human testicular biopsies at different stages of seminoma development via immunohistochemistry to confirm the cell lines’ representativeness. Furthermore, dye-transfer measurements were performed to investigate functional cell coupling. Results: Cx43, Cx45 and N-cadherin mRNA and protein were generally detectable in both cell lines via qualitative RT-PCR and Western blot. Immunocytochemistry and immunofluorescence revealed a mainly membrane-associated expression of N-cadherin in both cell lines, but gene expression values were higher in FS1 cells. Cx43 expression was also membrane-associated in FS1 cells but barely detectable in TCam-2 cells. Accordingly, a high gene expression value of Cx43 was measured for FS1 and a low value for TCam-2 cells. Cx45 was primary located in the cytoplasm of FS1 and TCam-2 cells and revealed similar low to medium gene expression values in both cell lines. Overall, results were comparable with corresponding biopsies. Additionally, both FS1 and TCam-2 cells showed dye diffusion into neighboring cells. Conclusion: The junctional proteins Cx43, Cx45 and N-cadherin are expressed in FS1 and TCam-2 cells at mRNA and/or protein level in different amounts and localizations, and cells of both lines are functionally coupled among each other. Concerning the expression of these junctional proteins, FS1 and TCam-2 cells are largely representative for Sertoli and seminoma cells, respectively. Thus, these results provide the basis for further coculture experiments evaluating the role of junctional proteins in context with seminoma progression

Steroid hormone bioavailability is controlled by the lymphatic system.

The steroid hormone progesterone accounts for immune tolerance in pregnancy. Enhanced progesterone metabolism to 6α-OH-pregnanolone occurs in complicated pregnancies such as in preeclampsia with preterm delivery or intrauterine growth restriction, and in cancer. As lymphatic endothelial cells (LECs) promote tumor immunity, we hypothesized that human LECs modify progesterone bioavailability. Primary human LECs and mice lymph nodes were incubated with progesterone and progesterone metabolism was analyzed by thin layer chromatography and liquid chromatography-mass spectrometry. Expression of steroidogenic enzymes, down-stream signal and steroid hormone receptors was assessed by Real-time PCR. The placental cell line HTR-8/SV neo was used as reference. The impact of the progesterone metabolites of interest was investigated on the immune system by fluorescence-activated cell sorting analysis. LECs metabolize progesterone to 6α-OH-pregnanolone and reactivate progesterone from a precursor. LECs highly express 17β-hydroxysteroid dehydrogenase 2 and are therefore antiandrogenic and antiestrogenic. LECs express several steroid hormone receptors and PIBF1. Progesterone and its metabolites reduced TNF-α and IFN-γ production in CD4+ and CD8+ T cells. LECs modify progesterone bioavailability and are a target of steroid hormones. Given the global area represented by LECs, they might have a critical immunomodulatory control in pregnancy and cancer

Supporting pre-service teachers in developing research competence

IntroductionTeachers need research competence to reflect on their teaching and to interpret and implement research-based recommendations. However, many pre-service teachers have critical attitudes toward research, little motivation to engage in research, and comparatively low knowledge of research methods and thereby consequently indicating a low research competence. Flexible online modules in university teaching could be a promising approach to address these issues. Online modules can potentially promote self-determined motivation, but should be sufficiently structured to support learners’ need for competence.MethodsWe designed two learning environments with different types of structure: a non-restrictive structured environment and a restrictive structured environment. A total of N = 108 pre-service biology teachers were randomly assigned to the two learning environments.Results and discussionContrary to our assumption, the restrictive type of structure of the learning environment did not lead to a higher perception of competence. This might be a consequence of external pressure, for example, the examination at the end of the course. Regarding pre-service teachers’ research competence, we found a decrease in the affective-motivational domain and an increase in the cognitive domain in both learning environments. These results suggest that fostering pre-service teachers’ research competence should focus on the affective-motivational domain. In order to positively affect this domain, care must be taken to ensure that structuring elements are not experienced as control and that given choices are meaningful to students

Acid Sphingomyelinase Deficiency Ameliorates Farber Disease

Farber disease is a rare lysosomal storage disorder resulting from acid ceramidase deficiency and subsequent ceramide accumulation. No treatments for Farber disease are clinically available, and affected patients have a severely shortened lifespan. We have recently reported a novel acid ceramidase deficiency model that mirrors the human disease closely. Acid sphingomyelinase is the enzyme that generates ceramide upstream of acid ceramidase in the lysosomes. Using our acid ceramidase deficiency model, we tested if acid sphingomyelinase could be a potential novel therapeutic target for the treatment of Farber disease. A number of functional acid sphingomyelinase inhibitors are clinically available and have been used for decades to treat major depression. Using these as a therapeutic for Farber disease, thus, has the potential to improve central nervous symptoms of the disease as well, something all other treatment options for Farber disease can’t achieve so far. As a proof-of-concept study, we first cross-bred acid ceramidase deficient mice with acid sphingomyelinase deficient mice in order to prevent ceramide accumulation. Double-deficient mice had reduced ceramide accumulation, fewer disease manifestations, and prolonged survival. We next targeted acid sphingomyelinase pharmacologically, to test if these findings would translate to a setting with clinical applicability. Surprisingly, the treatment of acid ceramidase deficient mice with the acid sphingomyelinase inhibitor amitriptyline was toxic to acid ceramidase deficient mice and killed them within a few days of treatment. In conclusion, our study provides the first proof-of-concept that acid sphingomyelinase could be a potential new therapeutic target for Farber disease to reduce disease manifestations and prolong survival. However, we also identified previously unknown toxicity of the functional acid sphingomyelinase inhibitor amitriptyline in the context of Farber disease, strongly cautioning against the use of this substance class for Farber disease patients

miTuner - a kit for microRNA based gene expression tuning in mammalian cells

The purpose of this RFC is to introduce a modular expression tuning kit for use in mammalian cells. The kit enables the regulation of the gene expression of any gene of interest (GOI) based on synthetic microRNAs, endogenous microRNAs or a combination of both

Preoperative evaluation of pulmonary artery morphology and pulmonary circulation in neonates with pulmonary atresia - usefulness of MR angiography in clinical routine

BACKGROUND: To explore the role of contrast-enhanced magnetic resonance angiography (CE-MRA) in clinical routine for evaluating neonates with pulmonary atresia (PA) and to describe their pulmonary artery morphology and blood supply.CE-MRA studies of 15 neonates with PA (12 female; median weight: 2900 g) were retrospectively evaluated by two radiologists in consensus. Each study was judged to be either diagnostic or non-diagnostic depending on the potential to evaluate pulmonary artery morphology and pulmonary blood supply. In those cases where surgery or conventional angiocardiography was performed results were compared. RESULTS: CE-MRA was considered diagnostic in 87%. Pulmonary artery morphology was classified as "confluent with (n = 1) and without (n = 1) main pulmonary artery", "non-confluent" (n = 6) or "absent" (n = 7). Source of pulmonary blood supply was "a persistent arterial duct" (n = 12), "a direct" (n = 22) or "indirect (n = 9) aortopulmonary collateral artery (APCA)" or "an APCA from the ascending aorta" (n = 2). In no patient were there any additional findings at surgery or conventional angiocardiography which would have changed the therapeutic or surgical approach. CONCLUSIONS: CE-MRA is a useful diagnostic tool for the preoperative evaluation of the morphology of pulmonary arteries and blood supply in neonates with PA. In most cases diagnostic cardiac catheterization can be avoided

LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

ISL1 is a major susceptibility gene for classic bladder exstrophy and a regulator of urinary tract development.

Previously genome-wide association methods in patients with classic bladder exstrophy (CBE) found association with ISL1, a master control gene expressed in pericloacal mesenchyme. This study sought to further explore the genetics in a larger set of patients following-up on the most promising genomic regions previously reported. Genotypes of 12 markers obtained from 268 CBE patients of Australian, British, German Italian, Spanish and Swedish origin and 1,354 ethnically matched controls and from 92 CBE case-parent trios from North America were analysed. Only marker rs6874700 at the ISL1 locus showed association (p = 2.22 × 10-08). A meta-analysis of rs6874700 of our previous and present study showed a p value of 9.2 × 10-19. Developmental biology models were used to clarify the location of ISL1 activity in the forming urinary tract. Genetic lineage analysis of Isl1-expressing cells by the lineage tracer mouse model showed Isl1-expressing cells in the urinary tract of mouse embryos at E10.5 and distributed in the bladder at E15.5. Expression of isl1 in zebrafish larvae staged 48 hpf was detected in a small region of the developing pronephros. Our study supports ISL1 as a major susceptibility gene for CBE and as a regulator of urinary tract development

miMeasure – a standard for miRNA binding site characterization in mammalian cells

This RFC proposes a standard for the quantitative characterization of miRNA binding sites (miRNA-BS) in mammalian cells. The miMeasure standard introduces a ready-to-use standard measurement plasmid (pSMB_miMeasure, BBa_K337049) enabling rapid experimental characterization of any miRNA-BS of choice. We recommend a new standard unit, RKDU (relative knock-down unit) to describe the knock-down efficiency of a miRNA-BS in a specific cell type. pSMB_miMeasure allows for an easy and fast measurement of RKDU while providing effective normalization against variance stemming from differences in transfection efficiency and from other sources