Immunogenicity of a secreted, C-terminally truncated, form of bovine viral diarrhea virus E2 glycoprotein as a potential candidate in subunit vaccine development.

Both current live, attenuated, and killed virus vaccines for bovine viral diarrhea virus (BVDV) have their limitations. Here, we report the development of a BVDV subunit vaccine by (i) the expression of a secreted form of a recombinant E2 glycoprotein using BHK21 cells and (ii) determination of the immune responses in mice. The E2 glycoprotein was modified by deletion of the C-terminal transmembrane anchor domain and fusion to a V5 epitope tag. This allowed detection using anti-V5 monoclonal antibodies together with simple purification of the expressed, secreted, form of E2 from the cell media. Furthermore, we genetically fused green fluorescent protein (GFP) linked to E2 via a Thosea asigna virus 2A (T2A) ribosome skipping sequence thereby creating a self-processing polyprotein [GFP-T2A-BVDV-E2trunk-V5], producing discrete [GFP-T2A] and [E2trunk-V5] translation products: GFP fluorescence acts, therefore, as a surrogate marker of E2 expression, BALB/c mice were inoculated with [E2trunk-V5] purified from cell media and both humoral and cellular immune responses were observed. Our antigen expression system provides, therefore, both (i) a simple antigen purification protocol together with (ii) a feasible strategy for further, large-scale, production of vaccines.

Effectiveness of immersive virtual reality training in nasogastric tube feeding education: A randomized controlled trial.

BACKGROUND: Given rapidly aging societies worldwide, improving the quality of long-term care through the cultivation of immense nursing assistants is critical. Accordingly, developing a satisfactory learning model to improve the learning outcomes of nursing assistant students is imperative. OBJECTIVE: This study tested the hypothesis that students in long-term care departments who underwent immersive virtual reality (IVR) training would have significantly (1) higher levels of knowledge about the skills of nasogastric tube feeding, (2) higher learning motivations (i.e., intrinsic and extrinsic motivations, task values, and self-efficacy), (3) lower cognitive load, and (4) higher satisfaction than a control group. DESIGN: A randomized controlled trial with pretest and posttest design. SETTINGS AND PARTICIPANTS: We randomly assigned 107 students from the long-term care departments of two universities in central Taiwan to the IVR group (n = 54) or the control group (n = 53). METHODS: The IVR group learned the procedure of nasogastric tube feeding through IVR, whereas the control group watched a 15-min 2D video. The participants filled pretest and posttest questionnaires on nasogastric tube feeding knowledge. After the experiment was completed, the participants answered another questionnaire on their learning motivations, cognitive load, and learning satisfaction. RESULTS: The nasogastric tube feeding knowledge improved significantly in the IVR and control groups after the intervention, with no significant between-group differences. The IVR group scored significantly higher than the control group on extrinsic goals, task value, and satisfaction; nevertheless, they also experienced a significantly higher cognitive load. CONCLUSIONS: Both the IVR training and the traditional 2D video improved the learning outcomes of the nursing assistant students. The students were more satisfied with IVR than with the conventional learning model and indicated that IVR inspired their extrinsic learning motivations and perceived task value. However, IVR incurred a high cognitive load, which must be addressed in future course designs.

Guanine nucleotide induced conformational change of Cdc42 revealed by hydrogen/deuterium exchange mass spectrometry.

Cdc42 regulates pathways related to cell division. Dysregulation of Cdc42 can lead to cancer, cardiovascular diseases and neurodegenerative diseases. GTP induced activation mechanism plays an important role in the activity and biological functions of Cdc42. P-loop, Switch I and Switch II are critical regions modulating the enzymatic activity of Cdc42. We applied amide hydrogen/deuterium exchange coupled with liquid chromatography mass spectrometry (HDXMS) to investigate the dynamic changes of apo-Cdc42 after GDP, GTP and GMP-PCP binding. The natural substrate GTP induced significant decreases of deuteration in P-loop and Switch II, moderate changes of deuteration in Switch I and significant changes of deuteration in the α7 helix, a region far away from the active site. GTP binding induced similar effects on H/D exchange to its non-hydrolysable analog, GMP-PCP. HDXMS results indicate that GTP binding blocked the solvent accessibility in the active site leading to the decrease of H/D exchange rate surrounding the active site, and further triggered a conformational change resulting in the drastic decrease of H/D exchange rate at the remote α7 helix. Comparing the deuteration levels in three activation states of apo-Cdc42, Cdc42-GDP and Cdc42-GMP-PCP, the apo-Cdc42 has the most flexible structure, which can be stabilized by guanine nucleotide binding. The rates of H/D exchange of Cdc42-GDP are between the GMP-PCP-bound and the apo form, but more closely to the GMP-PCP-bound form. Our results show that the activation of Cdc42 is a process of conformational changes involved with P-loop, Switch II and α7 helix for structural stabilization.