Promoting physical activity and youth development in schools: the case for near-peer coaches.

Background: Sports-based youth development (SBYD) programs provide an inclusive, supportive environment for promoting physical activity as well as nurturing the development of life skills which, in combination, promote physical, mental, and emotional health in youth. The Up2Us Sports SBYD program was implemented in six schools in New Orleans, Louisiana in 2020-2022, where near-peer coaches from the community were placed in schools and present throughout the school day. The intervention period straddled the COVID-19 pandemic as well as extreme weather events, modifying program delivery. Process/methods: An exploratory case study was conducted to understand participant experience amid program disruptions and modifications, as well as their perceptions of program impact on physical activity and health. Interviews with coaches (n = 7), focus groups with youth (n = 14) and program observation data were triangulated to provide a description of the case. Results: The major theme that emerged from the case study was the centrality of the near-peer mentorship relationships between coaches and youth. Participants believed near-peer relationships facilitated life skill development and increased opportunity for physical activity in schools, but pressures on coaches' time and external challenges in the community were limiting factors to the extent of program impact. Conclusion: This community case study demonstrates the potential role for near-peer mentors in influencing the health and wellbeing of youth from under-resourced communities and highlights the opportunity for school-based SBYD programming to provide youth with a consistent source of both relational and physical activity support.

Cleaving DNA with DNA: Cooperative Tuning of Structure and Reactivity Driven by Copper Ions.

A copper-dependent self-cleaving DNA (DNAzyme or deoyxyribozyme) previously isolated by in vitro selection has been analyzed by a combination of Molecular Dynamics (MD) simulations and advanced Electron Paramagnetic Resonance (Electron Spin Resonance) EPR/ESR spectroscopy, providing insights on the structural and mechanistic features of the cleavage reaction. The modeled 46-nucleotide deoxyribozyme in MD simulations forms duplex and triplex sub-structures that flank a highly conserved catalytic core. The DNA self-cleaving construct can also form a bimolecular complex that has a distinct substrate and enzyme domains. The highly dynamic structure combined with an oxidative site-specific cleavage of the substrate are two key-aspects to elucidate. By combining EPR/ESR spectroscopy with selectively isotopically labeled nucleotides it has been possible to overcome the major drawback related to the "metal-soup" scenario, also known as "super-stoichiometric" ratios of cofactors versus substrate, conventionally required for the DNA cleavage reaction within those nucleic acids-based enzymes. The focus on the endogenous paramagnetic center (Cu2+) here described paves the way for analysis on mixtures where several different cofactors are involved. Furthermore, the insertion of cleavage reaction within more complex architectures is now a realistic perspective towards the applicability of EPR/ESR spectroscopic studies.

Participant Perspectives on the Impact of a School-Based, Experiential Food Education Program Across Childhood, Adolescence, and Young Adulthood.

OBJECTIVE: Explore participant perceptions of involvement in an experiential food education program during elementary school and the scope and extent of program influence on food decisions. DESIGN: Focus groups with current participants and program alumni. SETTING: Washington, DC. PARTICIPANTS: Thirty-nine elementary school students and 39 program alumni ranging from middle school through university students. PHENOMENON OF INTEREST: Participant perceptions of program impact from childhood into adolescence and young adulthood. ANALYSIS: Inductive thematic analysis. RESULTS: Nine emergent themes were identified, spread over 3 categories of program impact: immediate, beyond the classroom, and sustained. Immediate program impact themes came from all participants and included enjoyment, hands-on learning, and fostering connection. Beyond the classroom, older elementary students and alumni expressed perceived shifts in individual and family food intake, involvement in household food practices, and desire for fresh food options at school. Themes of sustained program impact among alumni participants were an appreciation for fresh food, openness to trying new foods, and confidence to make informed food decisions. CONCLUSIONS AND IMPLICATIONS: Findings provide a deeper understanding of participant perspectives on the impact of participation in a school-based experiential food education program and a basis for further research on the role of early exposure to food education in influencing food decisions as children grow older.

NMR-identification of the interaction between BRCA1 and the intrinsically disordered monomer of the Myc-associated factor X.

The breast cancer susceptibility 1 (BRCA1) protein plays a pivotal role in modulating the transcriptional activity of the vital intrinsically disordered transcription factor MYC. In this regard, mutations of BRCA1 and interruption of its regulatory activity are related to hereditary breast and ovarian cancer (HBOC). Interestingly, so far, MYC's main dimerization partner MAX (MYC-associated factor X) has not been found to bind BRCA1 despite a high sequence similarity between both oncoproteins. Herein, we show that a potential reason for this discrepancy is the heterogeneous conformational space of MAX, which encloses a well-documented folded coiled-coil homodimer as well as a less common intrinsically disordered monomer state-contrary to MYC, which exists mostly as intrinsically disordered protein in the absence of any binding partner. We show that when the intrinsically disordered state of MAX is artificially overpopulated, the binding of MAX to BRCA1 can readily be observed. We characterize this interaction by nuclear magnetic resonance (NMR) spectroscopy chemical shift and relaxation measurements, complemented with ITC and SAXS data. Our results suggest that BRCA1 directly binds the MAX monomer to form a disordered complex. Though probed herein under biomimetic in-vitro conditions, this finding can potentially stimulate new perspectives on the regulatory network around BRCA1 and its involvement in MYC:MAX regulation.

Intrinsic Flexibility beyond the Highly Ordered DNA Tetrahedron: An Integrative Spectroscopic and Molecular Dynamics Approach.

Since the introduction of DNA-based architectures, in the past decade, DNA tetrahedrons have aroused great interest. Applications of such nanostructures require structural control, especially in the perspective of their possible functionalities. In this work, an integrated approach for structural characterization of a tetrahedron structure is proposed with a focus on the fundamental biophysical aspects driving the assembly process. To address such an issue, spin-labeled DNA sequences are chemically synthesized, self-assembled, and then analyzed by Continuous-Wave (CW) and pulsed Electron Paramagnetic Resonance (EPR) spectroscopy. Interspin distance measurements based on PELDOR/DEER techniques combined with molecular dynamics (MD) thus revealed unexpected dynamic heterogeneity and flexibility of the assembled structures. The observation of flexibility in these ordered 3D structures demonstrates the sensitivity of this approach and its effectiveness in accessing the main dynamic and structural features with unprecedented resolution.

Structural and functional insights into the activation of the dual incision activity of UvrC, a key player in bacterial NER.

Bacterial nucleotide excision repair (NER), mediated by the UvrA, UvrB and UvrC proteins is a multistep, ATP-dependent process, that is responsible for the removal of a very wide range of chemically and structurally diverse DNA lesions. DNA damage removal is performed by UvrC, an enzyme possessing a dual endonuclease activity, capable of incising the DNA on either side of the damaged site to release a short single-stranded DNA fragment containing the lesion. Using biochemical and biophysical approaches, we have probed the oligomeric state, UvrB- and DNA-binding abilities and incision activities of wild-type and mutant constructs of UvrC from the radiation resistant bacterium, Deinococcus radiodurans. Moreover, by combining the power of new structure prediction algorithms and experimental crystallographic data, we have assembled the first model of a complete UvrC, revealing several unexpected structural motifs and in particular, a central inactive RNase H domain acting as a platform for the surrounding domains. In this configuration, UvrC is maintained in a 'closed' inactive state that needs to undergo a major rearrangement to adopt an 'open' active state capable of performing the dual incision reaction. Taken together, this study provides important insight into the mechanism of recruitment and activation of UvrC during NER.

Narrow Near-Infrared Emission from InP QDs Synthesized with Indium(I) Halides and Aminophosphine.

Nonpyrophoric aminophosphines reacted with indium(III) halides in the presence of zinc chloride have emerged as promising phosphorus precursors in the synthesis of colloidal indium phosphide (InP) quantum dots (QDs). Nonetheless, due to the required P/In ratio of 4:1, it remains challenging to prepare large-sized (>5 nm), near-infrared absorbing/emitting InP QDs using this synthetic scheme. Furthermore, the addition of zinc chloride leads to structural disorder and the formation of shallow trap states inducing spectral broadening. To overcome these limitations, we introduce a synthetic approach relying on the use of indium(I) halide, which acts as both the indium source and reducing agent for aminophosphine. The developed zinc-free, single-injection method gives access to tetrahedral InP QDs with an edge length > 10 nm and narrow size distribution. The first excitonic peak is tunable from 450 to 700 nm by changing the indium halide (InI, InBr, InCl). Kinetic studies using phosphorus NMR reveal the coexistence of two reaction pathways, the reduction of transaminated aminophosphine by In(I) and via redox disproportionation. Etching the surface of the obtained InP QDs at room temperature with in situ-generated hydrofluoric acid (HF) leads to strong photoluminescence (PL) emission with a quantum yield approaching 80%. Alternatively, surface passivation of the InP core QDs was achieved by low-temperature (140 °C) ZnS shelling using the monomolecular precursor zinc diethyldithiocarbamate. The obtained InP/ZnS core/shell QDs that emit in a range of 507-728 nm exhibit a small Stokes shift (110-120 meV) and a narrow PL line width (112 meV at 728 nm).

Food Insecurity and Childhood Obesity: A Systematic Review.

BACKGROUND AND OBJECTIVES: Addressing food insecurity while promoting healthy body weights among children is a major public health challenge. Our objective is to examine longitudinal associations between food insecurity and obesity in US children aged 1 to 19 years. METHODS: Sources for this research include PubMed, CINAHL, and Scopus databases (January 2000 to February 2022). We included English language studies that examined food insecurity as a predictor of obesity or increased weight gain. We excluded studies outside the United States and those that only considered the unadjusted relationship between food security and obesity. Characteristics extracted included study design, demographics, methods of food security assessment, and anthropometric outcomes. RESULTS: Literature searches identified 2272 articles; 13 met our inclusion criteria. Five studies investigated the relationship between food insecurity and obesity directly, whereas 12 examined its relationship with body mass index or body mass index z-score. Three studies assessed multiple outcomes. Overall, evidence of associations between food insecurity and obesity was mixed. There is evidence for possible associations between food insecurity and obesity or greater weight gain in early childhood, for girls, and for children experiencing food insecurity at multiple time points. Heterogeneity in study methods limited comparison across studies. CONCLUSIONS: Evidence is stronger for associations between food insecurity and obesity among specific subgroups than for children overall. Deeper understanding of the nuances of this relationship is critically needed to effectively intervene against childhood obesity.

Photoactivatable V-Shaped Bifunctional Quinone Methide Precursors as a New Class of Selective G-quadruplex Alkylating Agents.

Combining the selectivity of G-quadruplex (G4) ligands with the spatial and temporal control of photochemistry is an emerging strategy to elucidate the biological relevance of these structures. In this work, we developed six novel V-shaped G4 ligands that can, upon irradiation, form stable covalent adducts with G4 structures via the reactive intermediate, quinone methide (QM). We thoroughly investigated the photochemical properties of the ligands and their ability to generate QMs. Subsequently, we analyzed their specificity for various topologies of G4 and discovered a preferential binding towards the human telomeric sequence. Finally, we tested the ligand ability to act as photochemical alkylating agents, identifying the covalent adducts with G4 structures. This work introduces a novel molecular tool in the chemical biology toolkit for G4s.

Urban Youth Perspectives on Food Insecurity during the COVID-19 Pandemic: Evidence from the COACHES Study.

School disruptions during the COVID-19 pandemic were a likely threat to food security and exacerbated risk factors associated with poor nutrition and health outcomes among low-income youth. As part of an ongoing school-based study aimed at improving physical activity and dietary behaviors (the COACHES study), associations between youth-reported food insecurity and dietary intake across the pandemic-affected academic year of 2020-2021 were examined. Middle school students (6th and 7th grade, 94% Black/African-American, 92% free-/reduced-price lunch eligible) answered validated surveys on food insecurity and diet and were measured for height and weight for calculation of weight status during Fall 2020 (n = 88) and Spring 2021 (n = 56). During this time, schools underwent a combination of in-person, hybrid, and remote learning. Nearly half of participants were overweight or obese (47%), and self-reported food insecurity was near 30% at both time points. Less than one-third of youth met fruit and vegetable intake guidelines, and more than half drank two or more sugar-sweetened beverages daily. While controlling for sex, maternal education, and weight status, food insecurity was not significantly associated with fruit and vegetable or sugar-sweetened beverage intake. Independent of weight status, youth were aware of being food insecure, yet it did not have an apparent impact on these food groups of concern. These findings highlight the need for greater understanding of youth perceptions of food insecurity in order to adequately address dietary quality and quantity concerns among children.

In vitro reconstitution of an efficient nucleotide excision repair system using mesophilic enzymes from Deinococcus radiodurans.

Nucleotide excision repair (NER) is a universal and versatile DNA repair pathway, capable of removing a very wide range of lesions, including UV-induced pyrimidine dimers and bulky adducts. In bacteria, NER involves the sequential action of the UvrA, UvrB and UvrC proteins to release a short 12- or 13-nucleotide DNA fragment containing the damaged site. Although bacterial NER has been the focus of numerous studies over the past 40 years, a number of key questions remain unanswered regarding the mechanisms underlying DNA damage recognition by UvrA, the handoff to UvrB and the site-specific incision by UvrC. In the present study, we have successfully reconstituted in vitro a robust NER system using the UvrABC proteins from the radiation resistant bacterium, Deinococcus radiodurans. We have investigated the influence of various parameters, including temperature, salt, protein and ATP concentrations, protein purity and metal cations, on the dual incision by UvrABC, so as to find the optimal conditions for the efficient release of the short lesion-containing oligonucleotide. This newly developed assay relying on the use of an original, doubly-labelled DNA substrate has allowed us to probe the kinetics of repair on different DNA substrates and to determine the order and precise sites of incisions on the 5' and 3' sides of the lesion. This new assay thus constitutes a valuable tool to further decipher the NER pathway in bacteria.

Signal-on/signal-off bead-based assays for the multiplexed monitoring of base excision repair activities by flow cytometry.

As the support of all living kingdoms' genetic information, the integrity of the DNA biomolecule must be preserved. To that goal, cells have evolved specific DNA repair pathways to thwart a large diversity of chemical substances and radiations that alter the DNA structure and lead to the development of pathologies such as cancers or neurodegenerative diseases. When dysregulated, activity rates of various actors of DNA repair can play a key role in carcinogenesis as well as in drugs resistance or hypersensitivity mechanisms. For the last 10 years, new complementary treatments have aimed at targeting specific enzymes responsible for such resistances. It is therefore crucial for biomedical research and clinical diagnosis to develop fast and sensitive tools able to measure the activity rate of DNA repair enzymes. In this work, a new assay for measuring enzymatic activities using microbeacons (µBs) is expounded. µB refers to microsphere functionalized by hairpin-shaped nucleic acid probes containing a single site-specific lesion in the stem and modified with chromophores. Following the processing of the lesion by the targeted protein, µB is cleaved and either lights off (signal-off strategy) or on (signal-on), depending on the use of fluorescent or profluorescent probes, respectively. After an optimization phase of the assay, we reported the combined analysis of restriction enzyme, AP-endonuclease, and DNA N-glycosylase by real-time monitoring followed by a flow cytometry measurement. As proofs of concept, we demonstrated the potential of the biosensor for highlighting DNA repair inhibitors and discriminating cell lines from their enzymatic activities.

Feasibility of collaborating with independent Latino-owned restaurants to increase sales of a healthy combo meal.

Americans spend the majority of their food dollars at restaurants and other prepared food sources, including quick-service and fast-food restaurants (PFS); independent small restaurants make up 66% of all PFS in the US. In this feasibility study, 5 independent and Latino-owned PFS in the Washington DC metro area worked with academic partners to start offering healthy combo meals with bottled water and promote these using on-site, community, and social media advertising. The number of healthy combos sold was collected weekly, showing that the new combos sold, and customers in all 5 sites were surveyed as they exited the PFS (n=50): >85% had noticed the combo meals; 100% thought it was a good idea to offer it, 68% had ordered the combo (of these, >94% of customers responded that they liked it).  Results suggest that it is feasible to work with independent Latino-owned restaurants to promote healthy combos and collect data.

Hydrogen Production at a NiO Photocathode Based on a Ruthenium Dye-Cobalt Diimine Dioxime Catalyst Assembly: Insights from Advanced Spectroscopy and Post-operando Characterization.

The production of hydrogen by efficient, low-cost, and integrated photoelectrochemical water splitting processes represents an important target for the ecological transition. This challenge can be addressed thanks to bioinspired chemistry and artificial photosynthesis approaches by designing dye-sensitized photocathodes for hydrogen production, incorporating bioinspired first-row transition metal-based catalysts. The present work describes the preparation and photoelectrochemical characterization of a NiO photocathode sensitized with a phosphonate-derivatized ruthenium tris-diimine photosensitizer covalently linked to a cobalt diimine dioxime hydrogen-evolving catalyst. Under simulated AM 1.5G irradiation, hydrogen is produced with photocurrent densities reaching 84 ± 7 µA·cm-2, which is among the highest values reported so far for dye-sensitized photocathodes with surface-immobilized catalysts. Thanks to the unique combination of advanced spectroscopy and surface characterization techniques, the fast desorption of the dyad from the NiO electrode and the low yield of electron transfer to the catalyst, resulting in the Co demetallation from the diimine dioxime framework, were identified as the main barriers limiting the performances and the stability of the system. This work therefore paves the way for a more rational design of molecular photocathodes for solar fuel production and represents a further step toward the development of sustainable processes for the production of hydrogen from sunlight and water.

Themes in Train-the-Trainer Nutrition Education Interventions Targeting Middle School Students: A Systematic Review.

Context-appropriate nutrition education interventions targeting middle school students have the potential to promote healthy dietary patters that may help prevent unnecessary weight gain at a point in childhood development when youth experience increasing agency over their food choices. The aim of this review was to identify and synthesize themes in train-the-trainer approaches, intervention content and delivery, and youth receptivity across teacher, mentor, and peer-led nutrition education interventions that targeted middle school-age youth in urban, primarily low-income settings. A systematic, electronic literature search was conducted in seven electronic databases, PubMed/Medline, CINAHL, ERIC, PsycINFO, Scopus, SPORTDiscus, and Cochrane CENTRAL, using fixed inclusion and exclusion criteria. A total of 53 papers representing 39 unique interventions were selected for data extraction and quality assessment. A framework synthesis approach was used to organize the interventions into six categories and identify themes according to whether the intervention was classroom-based or out-of-school-based and whether adults, cross-age peers or same-age peers delivered the intervention. Ten of the interventions contained multiple components such that they were included in two of the categories. The review findings indicated that trainings should be interactive, include opportunities to role-play intervention scenarios and provide follow-up support throughout intervention delivery. Interventions targeting middle school youth should include positive messaging and empower youth to make healthy choices within their specific food environment context.

Melting Curve Analysis of Aptachains: Adenosine Detection with Internal Calibration.

Small molecules are ubiquitous in nature and their detection is relevant in various domains. However, due to their size, sensitive and selective probes are difficult to select and the detection methods are generally indirect. In this study, we introduced the use of melting curve analysis of aptachains based on split-aptamers for the detection of adenosine. Aptamers, short oligonucleotides, are known to be particularly efficient probes compared to antibodies thanks to their advantageous probe/target size ratio. Aptachains are formed from dimers with dangling ends followed by the split-aptamer binding triggered by the presence of the target. The high melting temperature of the dimers served as a calibration for the detection/quantification of the target based on the height and/or temperature shift of the aptachain melting peak.

Adapting to supply-and-demand emerging trends for antigen-negative red blood cell units.

BACKGROUND: A global downtrend in blood usage has been observed by many countries, while the demand for antigen-negative red blood cell (RBC) units used in antigen-matched transfusions keeps increasing. The declining number of units collected exposes blood providers to a rapidly evolving supply challenge. METHODS: This study was conducted retrospectively with use of internal data analysis to weigh Québec's situation regarding global and antigen-negative RBC demand, to measure the effects of community-directed recruitment and blood drives, and to evaluate the benefits of mass-scale RBC genotyping. RESULTS: Our findings confirm a global RBC usage downtrend of over 20% total in the past 10 years with a steady antigen-negative usage and highlight the most requested negative antigen combinations. Our data also show our +39.5% progress regarding the number of Black donors recruited for antigen matching of patients with sickle cell disease in the past 3 years, as well as a constantly growing number of just-in-time blood collection for complex orders. Finally, our data summarize the efficiency of our mass-scale RBC genotyping efforts. CONCLUSION: Altogether, this study confirms the demand trends for regular and antigen-negative RBC units in Québec and the efficient effects of our recruitment and typing strategies.

The Arabidopsis thaliana Poly(ADP-Ribose) Polymerases 1 and 2 Modify DNA by ADP-Ribosylating Terminal Phosphate Residues.

Proteins from the poly(ADP-ribose) polymerase (PARP) family, such as PARP1 and PARP2, use NAD+ as a substrate to catalyze the synthesis of polymeric chains consisting of ADP-ribose units covalently attached to an acceptor molecule. PARP1 and PARP2 are viewed as DNA damage sensors that, upon binding to strand breaks, poly(ADP-ribosyl)ate themselves and nuclear acceptor proteins. The flowering plant Arabidopsis thaliana contains three genes encoding homologs of mammalian PARPs: atPARP1, atPARP2, and atPARP3. Both atPARP1 and atPARP2 contain poly(ADP-ribosyl)ating activity; however, it is unknown whether they could covalently modify DNA by ADP-ribosylating the strand break termini. Here, we report that similar to their mammalian counterparts, the plant atPARP1 and atPARP2 proteins ADP-ribosylate 5'-terminal phosphate residues in duplex DNA oligonucleotides and plasmid containing at least two closely spaced DNA strand breaks. AtPARP1 preferentially catalyzes covalent attachment of ADP-ribose units to the ends of recessed DNA duplexes containing 5'-phosphate, whereas atPARP2 preferentially ADP-ribosylates the nicked and gapped DNA duplexes containing the terminal 5'-phosphate. Similar to their mammalian counterparts, the plant PARP-catalyzed DNA ADP-ribosylation is particularly sensitive to the distance that separates two strand breaks in the same DNA molecule, 1.5 and 1 or 2 turns of helix for atPARP1 and atPARP2, respectively. PAR glycohydrolase (PARG) restored native DNA structure by hydrolyzing the PAR-DNA adducts generated by atPARPs. Biochemical and mass spectrometry analyses of the PAR-DNA adducts showed that atPARPs utilize phosphorylated DNA termini as an alternative to protein acceptor residues to catalyze PAR chain synthesis via phosphodiester bond formation between C1' of ADP-ribose and a phosphate residue of the terminal nucleotide in DNA fragment. Taken together, these data establish the presence of a new type of DNA-modifying activity in Arabidopsis PARPs, suggesting a possible role of DNA ADP-ribosylation in DNA damage signaling and repair of terrestrial plants.

Aqueous Synthesis of DNA-Functionalized Near-Infrared AgInS2/ZnS Core/Shell Quantum Dots.

Biocompatibility, biofunctionality, and chemical stability are essential criteria to be fulfilled by quantum dot (QD) emitters for bio-imaging and -sensing applications. In addition to these criteria, achieving efficient near-infrared (NIR) emission with nontoxic QDs remains very challenging. In this perspective, we developed water-soluble NIR-emitting AgInS2/ZnS core/shell (AIS/ZnS) QDs functionalized with DNA. The newly established aqueous route relying on a two-step hot-injection synthesis led to highly luminescent chalcopyrite-type AIS/ZnS core/shell QDs with an unprecedented photoluminescence quantum yield (PLQY) of 55% at 700 nm and a long photoluminescence (PL) decay time of 900 ns. Fast and slow hot injection of the precursors were compared for the AIS core QD synthesis, yielding a completely different behavior in terms of size, size distribution, stoichiometry, and crystal structure. The PL peak positions of both types of core QDs were 710 (fast) and 760 nm (slow injection) with PLQYs of 36 and 8%, respectively. The slow and successive incorporation of the Zn and S precursors during the subsequent shell growth step on the stronger emitting cores promoted the formation of a three-monolayer thick ZnS shell, evidenced by the increase of the average QD size from 3.0 to 4.8 nm. Bioconjugation of the AIS/ZnS QDs with hexylthiol-modified DNA was achieved during the ZnS shell growth, resulting in a grafting level of 5-6 DNA single strands per QD. The successful chemical conjugation of DNA was attested by UV-vis spectroscopy and agarose gel electrophoresis. Importantly, surface plasmon resonance imaging experiments using complementary DNA strands further corroborated the successful coupling and the stability of the AIS/ZnS-DNA QD conjugates as well as the preservation of the biological activity of the anchored DNA. The strong NIR emission and biocompatibility of these AIS/ZnS-DNA QDs provide a high potential for their use in biomedical applications.