Ligand Migration and Cavities within Scapharca Dimeric HbI: Studies by Time-Resolved Crystallo- graphy, Xe Binding, and Computational Analysis

SummaryAs in many other hemoglobins, no direct route for migration of ligands between solvent and active site is evident from crystal structures of Scapharca inaequivalvis dimeric HbI. Xenon (Xe) and organic halide binding experiments, along with computational analysis presented here, reveal protein cavities as potential ligand migration routes. Time-resolved crystallographic experiments show that photodissociated carbon monoxide (CO) docks within 5 ns at the distal pocket B site and at more remote Xe4 and Xe2 cavities. CO rebinding is not affected by the presence of dichloroethane within the major Xe4 protein cavity, demonstrating that this cavity is not on the major exit pathway. The crystal lattice has a substantial influence on ligand migration, suggesting that significant conformational rearrangements may be required for ligand exit. Taken together, these results are consistent with a distal histidine gate as one important ligand entry and exit route, despite its participation in the dimeric interface

Evaluation of the preventive capacities of a topically applied azithromycin formulation against Lyme borreliosis in a murine model

Objectives: Systemic antibiotic treatment of Lyme borreliosis is effective during the early stages of the infection, while chronic manifestations of the disease may remain refractory and difficult to treat. This study was carried out in order to evaluate the potential of topically applied azithromycin to eliminate the spirochaetal organisms in the skin of the freshly bitten host and thereby prevent Lyme borreliosis. Methods: Laboratory mice were challenged with Borrelia burgdorferi sensu stricto by needle inoculation or via infected ticks as vectors. Then, an azithromycin-containing formulation was applied once daily to the sites of exposure for three consecutive days. In the case of needle inoculation, a 5% azithromycin formulation was applied starting 1 h, 3 days and 5 days after infection. In the case of tick exposure, 4%, 10% and 20% azithromycin formulations were applied, starting directly after the detachment of the engorged ticks. Subsequently, the infection status of the mice was determined. Results: Concentrations of azithromycin in murine skin were >3800-fold higher than the published minimal inhibitory concentration for B. burgdorferi as soon as 3 h after the first application. After needle inoculation, spirochaetes were not detectable in all infected mice after treatment, if the first application started 1 h or even after 3 days post-infection. Furthermore, no borrelial organisms were detected after topical treatment when ticks were used for spirochaete inoculation. Conclusions: Our data indicate that topical treatment with a formulation containing azithromycin is a promising approach to prevent Lyme borreliosis shortly after a tick bite

Exploitation of Herpesviral Transactivation Allows Quantitative Reporter Gene-Based Assessment of Virus Entry and Neutralization

Herpesviral entry is a highly elaborated process requiring many proteins to act in precise conjunction. Neutralizing antibodies interfere with this process to abrogate viral infection. Based on promoter transactivation of a reporter gene we established a novel method to quantify herpesvirus entry and neutralization by antibodies. Following infection with mouse and human cytomegalovirus and Herpes simplex virus 1 we observed promoter transactivation resulting in substantial luciferase expression (>1000-fold). No induction was elicited by UV-inactivated viruses. The response was MOI-dependent and immunoblots confirmed a correlation between luciferase induction and pp72-IE1 expression. Monoclonal antibodies, immune sera and purified immunoglobulin preparations decreased virus-dependent luciferase induction dose-dependently, qualifying this approach as surrogate virus neutralization test. Besides the reduced hands-on time, this assay allows analysis of herpesvirus entry in semi-permissive and non-adherent cells, which were previously non-assessable but play significant roles in herpesvirus pathology

What Influences Attitudes and Confidence in Teaching Physics and Technology Topics? An Investigation in Kindergarten and Primary-School Trainee Teachers

This study investigated the correlations of general knowledge, vocational interests, and personality with trainee teachers’ attitudes and perceived capabilities in teaching physics and technology topics in kindergarten and primary school. A quantitative survey was composed using the Nature–Human–Society questionnaire, the general knowledge test BOWIT, the general interest structure test AIST-R, and the 10-item Big Five Inventory. The sample consisted of 196 female trainee teachers for kindergarten and primary school, and the results showed that only a few trainee teachers favoured teaching physics and technology topics. The bivariate analyses indicated that investigative and realistic interests were highly correlated with their confidence in teaching physics and technology topics, followed by significant relationships with possessing general knowledge in science and technology. The relationships with personality, especially neuroticism and extraversion, were also evident, but they were not as strong. The results were further differentiated in various subgroups (i.e., a group who favoured teaching physics and technology topics versus a group who did not, as well as a group with the typical interest profile of kindergarten and primary-school teachers versus a group with a social and investigative interest profile), which provided additional insights

Vocational Interests and Teaching Preferences: Who Prefers Which Teaching Topic in the Nature–Human–Society Subject?

This study focuses on the vocational interests of trainee teachers for kindergarten and primary school, investigating whether the RIASEC-interest dimensions are related to teaching preferences in the Swiss subject of Nature–Human–Society, which is characterized by its multidisciplinarity. Interests are a source of individual differences in people and important to study since they influence intrinsic motivation, and thus, behavior, effort, and occupational decisions. The results of the conducted survey, composed of the Nature–Human–Society questionnaire and the general interest structure test (AIST-R), show, in a sample of 220 participants, that trainee teachers’ vocational interests were partly related to their previous experiences in the specific content domains of Nature–Human–Society and slightly differed by gender. The RIASEC interest dimensions of social, investigative, realistic, and partly artistic evidence significant correlations with preferences in the teaching topics of the Nature–Human–Society subject. It became clear that trainee teachers with high realistic and investigative interests and low social and artistic interests tended to prefer thing-related teaching topics, while pronounced social and artistic interests with low realistic and investigative interests were associated with teaching preferences for people-related topics in the subject of Nature–Human–Society. The dominant role of Prediger’s people- versus thing-related interest orientation could thus also be confirmed in the choice of favorite teaching topics, signaling that teachers feel comfortable with those topics that match their interest structure

Play-Based Physics Learning in Kindergarten

This article highlights the importance of play as a learning approach in early physics education. It demonstrates the concept of an innovative didactic method that combines children’s free play with physics learning in kindergarten. This play-based learning approach enables children to experience and recognize physical laws in a self-directed, action-oriented, and playful manner. The article provides concrete insights into how kindergarten teachers can stimulate physics-related learning moments, starting from free-play situations. Moreover, it points out the teacher’s crucial role in creating suitable play environments, providing feedback in play, and facilitating sustained shared thinking after play. The article is based on the didactic development project “je-desto”, which aims to promote play-based science learning in kindergarten by familiarizing kindergarten teachers with this promising didactic approach. Accordingly, this article provides kindergarten teachers and experts in subject didactics an answer to what play-based physics learning can look in practice