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Importance: For myopia control to be beneficial, it would be important that the benefit of treatment (slowed eye growth) is not lost because of faster than normal growth (rebound) after discontinuing treatment., Objective: To determine whether there is a loss of treatment effect (rebound) after discontinuing soft multifocal contact lenses in children with myopia., Design, Setting, and Participants: The Bifocal Lenses in Nearsighted Kids 2 (BLINK2) cohort study involved children with myopia (aged 11-17 years at BLINK2 baseline) who completed the BLINK Study randomized clinical trial. Enrollment was from September 2019 through January 2021; follow-up was completed in January 2024. In the BLINK2 Study, all children wore high-add (+2.50 diopter [D]) multifocal soft contact lenses for 2 years and single-vision soft contact lenses during the third year to determine if rebound occurred., Exposure: High-add multifocal soft contact lenses and single-vision soft contact lenses., Main Outcomes and Measures: Eye length (optical biometry) and refractive error (cycloplegic autorefraction) were measured annually., Results: Of 248 participants enrolled in BLINK2, 235 completed the study. The median age at the baseline visit was 15 years (range, 11-17 years); 146 participants (59%) were female, and 102 (41%) were male. At baseline for BLINK2, mean (SD) axial length and spherical equivalent refractive error were 25.2 (0.9) mm and -3.40 (1.40) D, respectively. After participants switched from multifocal to single-vision contact lenses, axial elongation increased by 0.03 mm per year (95% CI, 0.01 to 0.05) regardless of their original BLINK treatment assignment (P = .81). There was also an increase in myopia progression after switching to single-vision lenses of -0.17 D per year (95% CI, -0.22 to -0.12) that did not depend on the original BLINK treatment assignment (P = .57). There continued to be a difference in axial length and refractive error throughout BLINK2 based on the BLINK Study treatment assignment with the original high-add group having shorter eyes and less myopia than the original medium-add (+1.50 D) and single-vision groups., Conclusions and Relevance: The BLINK2 Study found no evidence of a loss of treatment effect after discontinuing multifocal contact lenses in older teenagers. These data suggest eye growth and myopia progression returned to faster but age-expected rates and support continuing multifocal lenses until cessation of elongation and progression.

The thermoacidophilic red alga Cyanidioschyzon merolae survives its challenging environment likely in part by operating a carbon-concentrating mechanism (CCM). Here, we demonstrated that C. merolae's cellular affinity for CO2 is stronger than the affinity of its rubisco for CO2. This finding provided additional evidence that C. merolae operates a CCM while lacking the structures and functions characteristic of CCMs in other organisms. To test how such a CCM could function, we created a mathematical compartmental model of a simple CCM, distinct from those we have seen previously described in detail. The results of our modeling supported the feasibility of this proposed minimal and non-canonical CCM in C. merolae. To facilitate the robust modeling of this process, we measured and incorporated physiological and enzymatic parameters into the model. Additionally, we trained a surrogate machine learning model to emulate the mechanistic model and characterized the effects of model parameters on key outputs. This parameter exploration enabled us to identify model features that influenced whether the model met the experimentally derived criteria for functional carbon concentration and efficient energy usage. Such parameters included cytosolic pH, bicarbonate pumping cost and kinetics, cell radius, carboxylation velocity, number of thylakoid membranes, and CO2 membrane permeability. Our exploration thus suggested that a non-canonical CCM could exist in C. merolae and illuminated the essential features generally necessary for CCMs to function., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists.)

Rubisco activity is highly regulated and frequently limits carbon assimilation in crop plants. In the chloroplast, various metabolites can inhibit or modulate Rubisco activity by binding to its catalytic or allosteric sites, but this regulation is complex and still poorly understood. Using rice Rubisco, we characterised the impact of various chloroplast metabolites which could interact with Rubisco and modulate its activity, including photorespiratory intermediates, carbohydrates, amino acids; as well as specific sugar-phosphates known to inhibit Rubisco activity - CABP (2-carboxy-d-arabinitol 1,5-bisphosphate) and CA1P (2-carboxy-d-arabinitol 1-phosphate) through in vitro enzymatic assays and molecular docking analysis. Most metabolites did not directly affect Rubisco in vitro activity under both saturating and limiting concentrations of Rubisco substrates, CO2 and RuBP (ribulose-1,5-bisphosphate). As expected, Rubisco activity was strongly inhibited in the presence of CABP and CA1P. High physiologically relevant concentrations of the carboxylation product 3-PGA (3-phosphoglyceric acid) decreased Rubisco activity by up to 30%. High concentrations of the photosynthetically derived hexose phosphates fructose 6-phosphate (F6P) and glucose 6-phosphate (G6P) slightly reduced Rubisco activity under limiting CO2 and RuBP concentrations. Biochemical measurements of the apparent Vmax and Km for CO2 and RuBP (at atmospheric O2 concentration) and docking interactions analysis suggest that CABP/CA1P and 3-PGA inhibit Rubisco activity by binding tightly and loosely, respectively, to its catalytic sites (i.e. competing with the substrate RuBP). These findings will aid the design and biochemical modelling of new strategies to improve the regulation of Rubisco activity and enhance the efficiency and sustainability of carbon assimilation in rice., (© 2024 The Author(s).)

Protein biochemistry can provide valuable answers to better understand plant performance and responses to the surrounding environment. In this chapter, we describe the process of extracting proteins from plant leaf samples. We highlight the key aspects to take into consideration to preserve protein integrity, from sample collection to extraction and preparation or storage for subsequent analysis of protein abundance and/or enzymatic activities., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Rubisco fixes CO 2 through the carboxylation of ribulose 1,5-bisphosphate (RuBP) during photosynthesis, enabling the synthesis of organic compounds. The natural diversity of Rubisco properties represents an opportunity to improve its performance and there is considerable research effort focusing on better understanding the properties and regulation of the enzyme. This chapter describes a method for large-scale purification of Rubisco from leaves. After the extraction of Rubisco from plant leaves, the enzyme is separated from other proteins by fractional precipitation with polyethylene glycol followed by ion-exchange chromatography. This method enables the isolation of Rubisco in large quantities for a wide range of biochemical applications., (© 2024. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Rubisco is the key enzyme in photosynthesis, catalyzing fixation of carbon dioxide from the atmosphere into energy storage molecules. Several inefficiencies in Rubisco limit the rate of photosynthesis, and, therefore, the growth of the plant. Rubisco is sensitive to light, making deactivation of the enzyme upon sampling likely. Moreover, the indirect methods often used to study its activity make obtaining reliable data difficult. In this Chapter, we describe an approach to generate reliable and repeatable data for Rubisco activities, activation state and abundance in plant leaves. We include methods to sample and extract proteins, minimizing Rubisco degradation and deactivation. We describe radiometric techniques to measure Rubisco activities and calculate its activation state at the time of sampling, and to quantify its abundance., (Copyright © 2024. Published by Elsevier Inc.)

Introduction: Frailty has consistently demonstrated associations with poorer healthcare outcomes. Vascular guidelines have recognised the importance of frailty assessment. However, an abundance of frailty tools and a lack of prospective studies confirming suitability of routine frailty assessment in clinical practice has delayed the uptake of these guidelines. The Frailty Assessment in Vascular OUtpatients Review study speaks to this evidence gap. The primary aim is to assess feasibility of implementing routine frailty assessment in a reproducible outpatient setting. Secondary objectives include comparing prognostic values and interuser agreement across five frailty assessment tools., Methods and Analysis: This single-centre prospective cohort study of feasibility is conducted in a rapid-referral vascular surgery clinic, serving a population of 2 million. Adults with capacity (>18 years), attending a clinic for any reason, are eligible for inclusion. Five assessments are completed by patient (Rockwood Clinical Frailty Scale (CFS) and Frail NonDisabled Questionnaire), clinician (CFS, Healthcare Improvement Scotland FRAIL tool and 'Initial Clinical Evaluation') and researcher (11-item modified Frailty Index). Consistent with feasibility objectives, outcome measures include recruitment rates, frailty assessment completion rates, time-to-complete assessments and interuser variability. Electronic follow-up at 30 days and 1 year will assess home-time and mortality as prognostic indicators. Patients treated surgically/endovascularly will undergo additional 30-day and 1-year postoperative follow-up, outcome measures include: surgical procedure, mortality, complications (according to Clavien-Dindo Classification), length of stay, readmission rates, non-home discharge, home-time, higher social care requirements on discharge and amputation-free survival. Prognostic value will be compared by area under receiver operating characteristic curves. Continuous outcome variables will be analysed using Spearman's rank correlation coefficient. Interuser agreement will be compared by percentage agreement in Cohen's kappa coefficient.  ETHICS AND DISSEMINATION: The study is sponsored by National Health Service Greater Glasgow and Clyde (R&IUGN23CE014). London-Riverside REC (23/PR/0062) granted ethical approval. Results will be disseminated through publication in peer-reviewed vascular surgery and geriatric medicine themed journals and presentation at similar scientific conferences., Trials Registration Number: NCT06040658. Stage of study: pre-results., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Frailty is common in vascular patients and is recognized for its prognostic value. In the absence of consensus, a multitude of frailty assessment tools exist. This systematic review aimed to quantify the variety in these tools and describe their content and application to inform future research and clinical practice., Methods: Multiple cross-disciplinary electronic literature databases were searched from inception to August 2022. Studies describing frailty assessment in a vascular surgical population were eligible. Data extraction to a validated template included patient demographics, tool content, and analysis methods. A secondary systematic search for papers describing the psychometric properties of commonly used frailty tools was then performed., Results: Screening 5358 records identified 111 eligible studies, with an aggregate population of 5,418,236 patients. Forty-three differing frailty assessment tools were identified. One-third of these failed to assess frailty as a multidomain deficit and there was a reliance on assessing function and presence of comorbidity. Substantial methodological variability in data analysis and lack of methodological description was also identified. Published psychometric assessment was available for only 4 of the 10 most commonly used frailty tools. The Clinical Frailty Scale was the most studied and demonstrates good psychometric properties within a surgical population., Conclusions: Substantial heterogeneity in frailty assessment is demonstrated, precluding meaningful comparisons of services and data pooling. A uniform approach to assessment is required to guide future frailty research. Based on the literature, we make the following recommendations: frailty should be considered a continuous construct and the reporting of frailty tools' application needs standardized. In the absence of consensus, the Clinical Frailty Scale is a validated tool with good psychometric properties that demonstrates usefulness in vascular surgery., Competing Interests: Disclosures None., (Copyright © 2023 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Regulating the central CO2-fixing enzyme Rubisco is as complex as its ancient reaction mechanism and involves interaction with a series of cofactors and auxiliary proteins that activate catalytic sites and maintain activity. A key component among the regulatory mechanisms is the binding of sugar phosphate derivatives that inhibit activity. Removal of inhibitors via the action of Rubisco activase is required to restore catalytic competency. In addition, specific phosphatases dephosphorylate newly released inhibitors, rendering them incapable of binding to Rubisco catalytic sites. The best studied inhibitor is 2-carboxy-d-arabinitol 1-phosphate (CA1P), a naturally occurring nocturnal inhibitor that accumulates in most species during darkness and low light, progressively binding to Rubisco. As light increases, Rubisco activase removes CA1P from Rubisco, and the specific phosphatase CA1Pase dephosphorylates CA1P to CA, which cannot bind Rubisco. Misfire products of Rubisco's complex reaction chemistry can also act as inhibitors. One example is xylulose-1,5-bisphosphate (XuBP), which is dephosphorylated by XuBPase. Here we revisit key findings related to sugar phosphate derivatives and their specific phosphatases, highlighting outstanding questions and how further consideration of these inhibitors and their role is important for better understanding the regulation of carbon assimilation., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Experimental Biology.)

Purpose: The purpose of this study was to compare axial and peripheral eye elongation during myopia therapy with multifocal soft contact lenses., Methods: Participants were 294 children (177 [60.2%] girls) age 7 to 11 years old with between -0.75 diopters (D) and -5.00 D of myopia (spherical component) and less than 1.00 D astigmatism at baseline. Children were randomly assigned to Biofinity soft contact lenses for 3 years: D-designs with a +2.50 D addition, +1.50 D addition, or single vision. Five measurements of eye length were averaged at the fovea, ±20°, and ±30° in the horizontal and vertical meridians of the right eye using the Haag-Streit Lenstar LS 900., Results: Axial elongation over 3 years with single vision contact lenses was greater than peripheral elongation in the superior and temporal retinal qeuadrants by 0.07 mm (95% confidence interval [CI] = 0.05 to 0.09 mm) and 0.06 mm (95% CI = 0.03 to 0.09 mm) and similar in the inferior and nasal quadrants. Axial elongation with +2.50 D addition multifocal contact lenses was similar to peripheral elongation in the superior retinal quadrant and less than peripheral elongation in the inferior and nasal quadrants by -0.04 mm (95% CI = -0.06 to -0.01 mm) and -0.06 mm (95% CI = -0.09 to -0.02 mm)., Conclusions: Wearing +2.50 D addition multifocal contact lenses neutralized or reversed the increase in retinal steepness with single vision lenses. The mismatch between greater inhibition of elongation at the fovea than peripherally despite greater peripheral myopic defocus suggests that optical myopia therapy may operate through extensive spatial integration or mechanisms other than local defocus.

Oligomerization is a core structural feature that defines the form and function of many proteins. Most proteins form molecular complexes; however, there remains a dearth of diversity-driven structural studies investigating the evolutionary trajectory of these assemblies. Ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO) is one such enzyme that adopts multiple assemblies, although the origins and distribution of its different oligomeric states remain cryptic. Here, we retrace the evolution of ancestral and extant form II RuBisCOs, revealing a complex and diverse history of oligomerization. We structurally characterize a newly discovered tetrameric RuBisCO, elucidating how solvent-exposed surfaces can readily adopt new interactions to interconvert or give rise to new oligomeric states. We further use these principles to engineer and demonstrate how changes in oligomerization can be mediated by relatively few mutations. Our findings yield insight into how structural plasticity may give rise to new oligomeric states.

Functional and active Rubisco is essential for CO 2 fixation and is a primary target for engineering approaches to increasing crop yields. However, the assembly and maintenance of active Rubisco are dependent on the coordinated biosynthesis of at least 11 nuclear-encoded proteins, termed the 'Rubiscosome'. Using publicly available gene expression data for wheat (Triticum aestivum L.), we show that the expression of Rubiscosome genes is balanced across the three closely related subgenomes that form the allohexaploid genome. Each subgenome contains a near complete set of homoeologous genes and contributes equally to overall expression, both under optimal and under heat stress conditions. The expression of the wheat thermo-tolerant Rubisco activase isoform 1β increases under heat stress and remains balanced across the subgenomes, albeit with a slight shift towards greater contribution from the D subgenome. The findings show that the gene copies in all three subgenomes need to be accounted for when designing strategies for crop improvement., (© 2022. The Author(s).)