No abstract

Evidence is emerging that inorganic polyphosphate (polyP) is a fundamental molecule involved in a wide range of biological processes. In higher eukaryotes, polyP is abundant in osteoblasts but questions remain as to its functions. Here, we find that polyP is particularly enriched in endoplasmic reticulum (ER) where it colocalizes with cyclophilin B (CypB) using osteoblastic SaOS-2 model cell line. PolyP binds directly and specifically to CypB, inhibiting its peptidyl-prolyl cis-trans isomerase activity which is critical for collagen folding. PolyP sequestration by spermine and ERspecific polyP reduction by polyphosphatase expression in cells reduced collagen misfolding and confirmed that endogenous polyP acts as a molecular control of CypB-mediated collagen folding. We propose that polyP is a previously unrecognized critical regulator of protein homeostasis in ER.

No abstract

Examinations present an intensely focused opportunity for student learning yet opportunities for collaboration, communication, and feedbacks are often wasted. Two‐stage examinations where students first take examinations individually and then repeat the examination in small groups hold promise to address this issue. Here, we pilot and evaluate a two‐stage examination within an advanced undergraduate biomedical sciences course. We evaluated this innovation by triangulation of data from a questionnaire, semi‐structured student interviews, as well as, comparison of student grades between stages of examination across higher‐ and lower‐performing student groups. Quantitative data from the structured questionnaire showed that a majority of students perceived the collaborative stage of two‐stage examinations successful in promoting peer collaboration and communication. Furthermore, there was deepened conceptual understanding and provision of immediate feedback. The two‐stage examination did not, however, ameliorate students' test anxiety. Qualitative data from semi‐structured student interviews were consistent with quantitative data to show that a two‐stage examination provides positive impact particularly on immediate feedback, peer collaboration and communication but contributed to sustained test anxiety possibly due to negative experiences during group interactions. Both lower‐ and higher‐performing students showed improvement in the collaborative stage as compared to the preceding individual stage of two‐stage examination. This would suggest possible benefits of two‐stage examination for learning for all student abilities. This study discusses the advantages and pitfalls of two‐stage examinations for biomedical sciences and will guide informed recommendations for subsequent implementation elsewhere.

No abstract