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result(s) for
"Briones, Andrea"
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A self-assembled protein β-helix as a self-contained biofunctional motif
2025
Nature constructs matter by employing protein folding motifs, many of which have been synthetically reconstituted to exploit function. A less understood motif whose structure-function relationships remain unexploited is formed by parallel β-strands arranged in a helical repetitive pattern, termed a β-helix. Herein we reconstitute a protein β-helix by design and endow it with biological function. Unlike β-helical proteins, which are contiguous covalent structures, this β-helix self-assembles from an elementary sequence of 18 amino acids. Using a combination of experimental and computational methods, we demonstrate that the resulting assemblies are discrete cylindrical structures exhibiting conserved dimensions at the nanoscale. We provide evidence for the structures to form a carpet-like three-dimensional scaffold promoting and inhibiting the growth of human and bacterial cells, respectively, while being able to mediate intracellular gene delivery. The study introduces a self-assembled β-helix as a self-contained bio- and multi-functional motif for exploring and exploiting mechanistic biology.
The structure-function relationships of a β-helix, a folding motif formed by parallel β-strands arranged in a helical repetitive pattern, remain poorly understood and underexploited. Here, the authors reconstitute a protein β-helix by design from an elementary sequence of 18 amino acids, which self-assembles into a self-contained multifunctional motif exhibiting a range of biological functions.
Journal Article
Heat Treatment and β-Carotene Incorporation Effect in the Interaction of β-Lactoglobulin and Carboxymethylcellulose System
by
Oliveira, Marco Aurélio Schüler
,
Goltz, Caroline
,
Mafra, Marcos R.
in
Analytical Chemistry
,
beta-carotene
,
beta-lactoglobulin
2016
Encapsulation technologies using proteins or polysaccharides can be employed with the purpose of solubilizing and protecting carotenoids. However, information on the role of protein and polysaccharide interactions is still slightly limited. The aim of this work was to investigate the effect of β-carotene linked to protein β-lactoglobulin (BLG) in the interaction carboxymethylcellulose (CMC) using isothermal titration calorimetry (ITC). Firstly, BLG and CMC interaction was assessed by means of turbidity analysis. Based on the results of turbidity, the thermodynamic profile of BLG-CMC complexes at pH 4.0 was obtained using ITC analysis at 25 °C. Afterward, it was evaluated the effect of a thermal treatment applied to the BLG (68 °C for 50 min) in the interaction with CMC also using ITC and circular dichroism (CD). ITC and CD analysis showed that the heat treatment applied on BLG did not cause changes in molecular interactions. The binding isotherm of BLG-CMC complexes incorporated with β-carotene showed an increase in the molar ratio and a slight decrease in enthalpy of the system. Incorporation of β-carotene in the system did not significantly affect the BLG and CMC interaction, suggesting this system can be applied in food application as encapsulation.
Journal Article
Standards and Metrology for Viral Vectors as Molecular Tools: Outcomes from a CCQM Workshop
by
Cleveland, Thomas E.
,
Huggett, Jim F.
,
Khan, Arifa S.
in
analytical methods
,
Biotechnology
,
characterisation
2024
Viral vectors are agents enabling gene transfer and genome editing and have widespread utility across the healthcare and biotechnology sectors. In January 2023, the International Bureau for Weights and Measures’ Consultative Committee for Amount of Substance (CCQM) held a workshop on Metrology for Viral systems as molecular tools. The workshop brought together international leaders from across regulatory, industry, government science, and metrology sectors to better understand key challenges for the community: Exploring current limitations in the measurement of virus-derived, virus-based, and virus-like systems in terms of quantification and characterisation; surveying the state-of-the-art in analytical methods and reference material provision for these entities; and initiating a dialog for the strategic development and implementation of suitable standardisation approaches for this sector. This article presents the workshop background and rationale, presentation summaries, conclusions, and recommendations.
Journal Article
Training for Racial Equity: Understanding Elementary Teacher Experiences and Perceptions
This qualitative study explored how elementary public school teachers perceive their capacity to shift mindsets, address systemic inequities, and improve outcomes for students of color following equity and inclusion professional development. Grounded in Critical Race Theory (CRT), the research examined how equity-centered training promotes culturally responsive teaching practices to meet the needs of marginalized racial groups. The study was guided by three research questions: how teachers perceive their ability to improve outcomes for students of color, how equity training influences their pedagogy, and what experiences compel them to adopt culturally responsive practices.Fifteen elementary teachers from a Missouri school district participated in semi-structured interviews, with representation from schools serving diverse populations. Data analysis revealed five themes: Whiteness as property, the permanence of racism, interest convergence, preparedness, and teacher self-efficacy. While professional development raised awareness of biases and systemic barriers, participants faced challenges such as insufficient preparation and systemic obstacles in implementing equitable practices.The findings underscore the transformative potential of equity-centered professional development in addressing racial inequities and the need for systemic changes to sustain progress. Recommendations include enhancing teacher preparation programs and refining professional development to explicitly address racial equity. This study contributes to the literature on racial equity in education by highlighting the interplay between teacher self-efficacy, systemic reforms, and the creation of inclusive learning environments for students of color.
Dissertation
COI1-dependent jasmonate signalling affects growth, metabolite production and cell wall protein composition in arabidopsis
by
O’Brien, José A
,
Whitelegge, Julian P
,
Daudi, Arsalan
in
Acetates - metabolism
,
alanine
,
apoplast
2018
Abstract
Background and Aims
Cultured cell suspensions have been the preferred model to study the apoplast as well as to monitor metabolic and cell cycle-related changes. Previous work showed that methyl jasmonate (MeJA) inhibits leaf growth in a CORONATINE INSENSITIVE 1 (COI1)-dependent manner, with COI1 being the jasmonate (JA) receptor. Here, the effect of COI1 overexpression on the growth of stably transformed arabidopsis cell cultures is described.
Methods
Time-course experiments were carried out to analyse gene expression, and protein and metabolite levels.
Key Results
Both MeJA treatment and the overexpression of COI1 modify growth, by altering cell proliferation and expansion. DNA content as well as transcript patterns of cell cycle and cell wall remodelling markers were altered. COI1 overexpression also increases the protein levels of OLIGOGALACTURONIDE OXIDASE 1, BETA-GLUCOSIDASE/ENDOGLUCANASES and POLYGALACTURONASE INHIBITING PROTEIN2, reinforcing the role of COI1 in mediating defence responses and highlighting a link between cell wall loosening and growth regulation. Moreover, changes in the levels of the primary metabolites alanine, serine and succinic acid of MeJA-treated Arabidopsis cell cultures were observed. In addition, COI1 overexpression positively affects the availability of metabolites such as β-alanine, threonic acid, putrescine, glucose and myo-inositol, thereby providing a connection between JA-inhibited growth and stress responses.
Conclusions
This study contributes to the understanding of the regulation of growth and the production of metabolic resources by JAs and COI1. This will have important implications in dissecting the complex relationships between hormonal and cell wall signalling in plants. The work also provides tools to uncover novel mechanisms co-ordinating cell division and post-mitotic cell expansion in the absence of organ developmental control.
Journal Article
Evaluation of flare rate and reduction strategies for bDMARDs in juvenile idiopathic arthritis: real world data from a single-centre cohort
2022
This study aimed to determine the flare rate (FR) in a cohort of Juvenile Idiopathic Arthritis (JIA) patients with tapered or abruptly discontinued biologic disease-modifying anti-rheumatic drugs (bDMARDs) and to identify predictors of flare. This retrospective observational study included 191 bDMARD dose-reduction events in patients with JIA followed-up at a referral hospital during the period 2000–2019. FR was analysed according to reduction strategies. To identify predictors of flare, Kaplan–Meier and Cox-regression models were plotted at 6 months (6 m), 12 months (12 m) and 24 months (24 m) following tapering (TP) or withdrawal (WD). 165 episodes of TP and 71 episodes of WD were included; 45 episodes where treatment was withdrawn after TP were included in both strategies. FR after TP was 13.4% at 6 m and increased up to 26.6% at 12 m and 51.4% at 24 m. After WD, FR was higher, 52.1% of events had a flare at 6 m and 67.6% at 12 m. Previous TP did not increase time in remission after WD of bDMARDs in the Kaplan–Meier analysis. Factors associated with flares were identified after TP at 6 m: female sex, higher number of previous bDMARDs and longer time on bDMARD treatment were positively associated with flares. Polyarticular subtype and younger age at diagnosis were associated with flares at 12 and 24 m after TP. No factors were identified in multivariable analysis after WD. TP is a successful strategy to maintain remission with lower bDMARD doses. Previous TP of bDMARDs does not seem to increase time in remission after WD.
Journal Article
Heat Treatment and beta-Carotene Incorporation Effect in the Interaction of beta-Lactoglobulin and Carboxymethylcellulose System
by
Mafra, Marcos R
,
Igarashi-mafra, Luciana
,
Bonassoli, Andrea Briones; Gonçalves
in
Calorimetry
,
Carbohydrates
,
Carotenoids
2016
Encapsulation technologies using proteins or polysaccharides can be employed with the purpose of solubilizing and protecting carotenoids. However, information on the role of protein and polysaccharide interactions is still slightly limited. The aim of this work was to investigate the effect of [beta]-carotene linked to protein [beta]-lactoglobulin (BLG) in the interaction carboxymethylcellulose (CMC) using isothermal titration calorimetry (ITC). Firstly, BLG and CMC interaction was assessed by means of turbidity analysis. Based on the results of turbidity, the thermodynamic profile of BLG-CMC complexes at pH 4.0 was obtained using ITC analysis at 25 °C. Afterward, it was evaluated the effect of a thermal treatment applied to the BLG (68 °C for 50 min) in the interaction with CMC also using ITC and circular dichroism (CD). ITC and CD analysis showed that the heat treatment applied on BLG did not cause changes in molecular interactions. The binding isotherm of BLG-CMC complexes incorporated with [beta]-carotene showed an increase in the molar ratio and a slight decrease in enthalpy of the system. Incorporation of [beta]-carotene in the system did not significantly affect the BLG and CMC interaction, suggesting this system can be applied in food application as encapsulation.
Journal Article