Optical Tweezers Approaches for Probing Multiscale Protein Mechanics and Assembly

Multi-step assembly of individual protein building blocks is key to the formation of essential higher-order structures inside and outside of cells. Optical tweezers is a technique well suited to investigate the mechanics and dynamics of these structures at a variety of size scales. In this mini-review, we highlight experiments that have used optical tweezers to investigate protein assembly and mechanics, with a focus on the extracellular matrix protein collagen. These examples demonstrate how optical tweezers can be used to study mechanics across length scales, ranging from the single-molecule level to fibrils to protein networks. We discuss challenges in experimental design and interpretation, opportunities for integration with other experimental modalities, and applications of optical tweezers to current questions in protein mechanics and assembly

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Enhanced Hyaluronan Signaling and Autophagy Dysfunction by VPS35 D620N

The motor features of Parkinson’s disease (PD) result from the loss of dopaminergic (DA) neurons in the substantia nigra with autophagy dysfunction being closely linked to this disease. A PD-causing familial mutation in VPS35 (D620N) has been reported to inhibit autophagy. In order to identify signaling pathways responsible for this autophagy defect, we performed an unbiased screen using RNA sequencing (RNA-Seq) of wild-type or VPS35 D620N-expressing retinoic acid-differentiated SH-SY5Y cells. We report that VPS35 D620N-expressing cells exhibit transcriptome changes indicative of alterations in extracellular matrix (ECM)-receptor interaction as well as PI3K-AKT signaling, a pathway known to regulate autophagy. Hyaluronan (HA) is a major component of brain ECM and signals via the ECM receptors CD44, a top RNA-Seq hit, and HA-mediated motility receptor (HMMR) to the autophagy-regulating PI3K-AKT pathway. We find that high (\u3e950 kDa), but not low (15–40 kDa), molecular weight HA treatment inhibits autophagy. In addition, VPS35 D620N facilitated enhanced HA-AKT signaling. Transcriptomic assessment and validation of protein levels identified the differential expression of CD44 and HMMR isoforms in VPS35 D620N mutant cells. We report that knockdown of HMMR or CD44 results in upregulated autophagy in cells expressing wild-type VPS35. However, only HMMR knockdown resulted in rescue of autophagy dysfunction by VPS35 D620N indicating a potential pathogenic role for this receptor and HA signaling in Parkinson’s disease

A New Prepayment Model (with Default): An Occupation-time Derivative Approach

Prepayment, Fixed-rate mortgages, Option-pricing theory, Occupation-time derivatives, Parisian options,