Effects of school-based physical activity and multi-micronutrient supplementation intervention on growth, health and well-being of schoolchildren in three African countries: the KaziAfya cluster randomised controlled trial protocol with a 2 x 2 factorial design

Background In low- and middle-income countries, infectious diseases remain a key public health issue. Additionally, non-communicable diseases are a rapidly growing public health problem that impose a considerable burden on population health. One way to address this dual disease burden, is to incorporate (lifestyle) health promotion measures within the education sector. In the planned study, we will (i) assess and compare physical activity, physical fitness, micronutrient status, body composition, infections with soil-transmitted helminths, Schistosoma mansoni, malaria, inflammatory and cardiovascular health risk markers, cognitive function, health-related quality of life, and sleep in schoolchildren in Côte d’Ivoire, South Africa and Tanzania. We will (ii) determine the bi- and multivariate associations between these variables and (iii) examine the effects of a school-based health intervention that consists of physical activity, multi-micronutrient supplementation, or both. Methods Assuming that no interaction occurs between the two interventions (physical activity and multi-micronutrient supplementation), the study is designed as a cluster-randomised, placebo-controlled trial with a 2 × 2 factorial design. Data will be obtained at three time points: at baseline and at 9 months and 21 months after the baseline assessment. In each country, 1320 primary schoolchildren from grades 1–4 will be recruited. In each school, classes will be randomly assigned to one of four interventions: (i) physical activity; (ii) multi-micronutrient supplementation; (iii) physical activity plus multi-micronutrient supplementation; and (iv) no intervention, which will serve as the control. A placebo product will be given to all children who do not receive multi-micronutrient supplementation. After obtaining written informed consent from the parents/guardians, the children will be subjected to anthropometric, clinical, parasitological and physiological assessments. Additionally, fitness tests will be performed, and children will be invited to wear an accelerometer device for 7 days to objectively assess their physical activity. Children infected with S. mansoni and soil-transmitted helminths will receive deworming drugs according to national policies. Health and nutrition education will be provided to the whole study population independently of the study arm allocation. Discussion The study builds on the experience and lessons of a previous study conducted in South Africa. It involves three African countries with different social-ecological contexts to investigate whether results are generalisable across the continent

Conformational changes during pore formation by the perforin-related protein pleurotolysin

Membrane attack complex/perforin-like (MACPF) proteins comprise the largest superfamily of pore-forming proteins, playing crucial roles in immunity and pathogenesis. Soluble monomers assemble into large transmembrane pores via conformational transitions that remain to be structurally and mechanistically characterised. Here we present an 11 Å resolution cryo-electron microscopy (cryo-EM) structure of the two-part, fungal toxin Pleurotolysin (Ply), together with crystal structures of both components (the lipid binding PlyA protein and the pore-forming MACPF component PlyB). These data reveal a 13-fold pore 80 Å in diameter and 100 Å in height, with each subunit comprised of a PlyB molecule atop a membrane bound dimer of PlyA. The resolution of the EM map, together with biophysical and computational experiments, allowed confident assignment of subdomains in a MACPF pore assembly. The major conformational changes in PlyB are a ~70° opening of the bent and distorted central β-sheet of the MACPF domain, accompanied by extrusion and refolding of two α-helical regions into transmembrane β-hairpins (TMH1 and TMH2). We determined the structures of three different disulphide bond-trapped prepore intermediates. Analysis of these data by molecular modelling and flexible fitting allows us to generate a potential trajectory of β-sheet unbending. The results suggest that MACPF conformational change is triggered through disruption of the interface between a conserved helix-turn-helix motif and the top of TMH2. Following their release we propose that the transmembrane regions assemble into β-hairpins via top down zippering of backbone hydrogen bonds to form the membrane-inserted β-barrel. The intermediate structures of the MACPF domain during refolding into the β-barrel pore establish a structural paradigm for the transition from soluble monomer to pore, which may be conserved across the whole superfamily. The TMH2 region is critical for the release of both TMH clusters, suggesting why this region is targeted by endogenous inhibitors of MACPF function

HIV Risk among MSM in Senegal: A Qualitative Rapid Assessment of the Impact of Enforcing Laws That Criminalize Same Sex Practices

Men who have sex with men (MSM) are at high risk for HIV in Senegal, with a prevalence of 21.5%. In December 2008, nine male HIV prevention workers were imprisoned for “acts against nature” prohibited by Senegalese law. This qualitative study assessed the impact of these arrests on HIV prevention efforts. A purposive sample of MSM in six regions of Senegal was recruited by network referral. 26 in-depth interviews (IDIs) and 6 focus group discussions (FGDs) were conducted in July–August 2009. 14 key informants were also interviewed. All participants reported pervasive fear and hiding among MSM as a result of the December 2008 arrests and publicity. Service providers suspended HIV prevention work with MSM out of fear for their own safety. Those who continued to provide services noticed a sharp decline in MSM participation. An effective response to the HIV epidemic in Senegal should include active work to decrease enforcement of this law

Cryo‐EM structure of MsbA in saposin‐lipid nanoparticles (Salipro) provides insights into nucleotide coordination

The ATP-binding cassette transporter MsbA is a lipid flippase, translocating lipid A, glycolipids, and lipopolysaccharides from the inner to the outer leaflet of the inner membrane of Gram-negative bacteria. It has been used as a model system for time-resolved structural studies as several MsbA structures in different states and reconstitution systems (detergent/nanodiscs/peptidiscs) are available. However, due to the limited resolution of the available structures, detailed structural information on the bound nucleotides has remained elusive. Here, we have reconstituted MsbA in saposin A–lipoprotein nanoparticles (Salipro) and determined the structure of ADP-vanadate-bound MsbA by single-particle cryo-electron microscopy to 3.5 Å resolution. This procedure has resulted in significantly improved resolution and enabled us to model all side chains and visualise detailed ADP-vanadate interactions in the nucleotide-binding domains. The approach may be applicable to other dynamic membrane proteins

Synthetic Precursors for TCNQF₄^2– Compounds: Synthesis, Characterization, and Electrochemical Studies of (Pr₄N)₂TCNQF₄ and Li₂TCNQF₄

Careful control of the reaction stoichiometry and conditions enables the synthesis of both LiTCNQF₄ and Li₂TCNQF₄ to be achieved. Reaction of LiI with TCNQF₄, in a 4:1 molar ratio, in boiling acetonitrile yields Li₂TCNQF₄. However, deviation from this ratio or the reaction temperature gives either LiTCNQF₄ or a mixture of Li₂TCNQF₄ and LiTCNQF₄. This is the first report of the large-scale chemical synthesis of Li₂TCNQF₄. Attempts to prepare a single crystal of Li₂TCNQF₄ have been unsuccessful, although air-stable (Pr₄N)₂TCNQF₄ was obtained by mixing Pr₄NBr with Li₂TCNQF₄ in aqueous solution. Pr₄NTCNQF₄ was also obtained by reaction of LiTCNQF₄ with Pr₄NBr in water. Li₂TCNQF₄, (Pr₄N)₂TCNQF₄, and Pr₄NTCNQF₄ have been characterized by UV–vis, FT-IR, Raman, and NMR spectroscopy, high resolution electrospray ionization mass spectrometry, and electrochemistry. The structures of single crystals of (Pr₄N)₂TCNQF₄ and Pr₄NTCNQF₄ have been determined by X-ray crystallography. These TCNQF₄^2– salts will provide useful precursors for the synthesis of derivatives of the dianions

Synthetic Precursors for TCNQF₄^2– Compounds: Synthesis, Characterization, and Electrochemical Studies of (Pr₄N)₂TCNQF₄ and Li₂TCNQF₄

Careful control of the reaction stoichiometry and conditions enables the synthesis of both LiTCNQF₄ and Li₂TCNQF₄ to be achieved. Reaction of LiI with TCNQF₄, in a 4:1 molar ratio, in boiling acetonitrile yields Li₂TCNQF₄. However, deviation from this ratio or the reaction temperature gives either LiTCNQF₄ or a mixture of Li₂TCNQF₄ and LiTCNQF₄. This is the first report of the large-scale chemical synthesis of Li₂TCNQF₄. Attempts to prepare a single crystal of Li₂TCNQF₄ have been unsuccessful, although air-stable (Pr₄N)₂TCNQF₄ was obtained by mixing Pr₄NBr with Li₂TCNQF₄ in aqueous solution. Pr₄NTCNQF₄ was also obtained by reaction of LiTCNQF₄ with Pr₄NBr in water. Li₂TCNQF₄, (Pr₄N)₂TCNQF₄, and Pr₄NTCNQF₄ have been characterized by UV–vis, FT-IR, Raman, and NMR spectroscopy, high resolution electrospray ionization mass spectrometry, and electrochemistry. The structures of single crystals of (Pr₄N)₂TCNQF₄ and Pr₄NTCNQF₄ have been determined by X-ray crystallography. These TCNQF₄^2– salts will provide useful precursors for the synthesis of derivatives of the dianions

Synthetic Precursors for TCNQF₄^2– Compounds: Synthesis, Characterization, and Electrochemical Studies of (Pr₄N)₂TCNQF₄ and Li₂TCNQF₄

Careful control of the reaction stoichiometry and conditions enables the synthesis of both LiTCNQF₄ and Li₂TCNQF₄ to be achieved. Reaction of LiI with TCNQF₄, in a 4:1 molar ratio, in boiling acetonitrile yields Li₂TCNQF₄. However, deviation from this ratio or the reaction temperature gives either LiTCNQF₄ or a mixture of Li₂TCNQF₄ and LiTCNQF₄. This is the first report of the large-scale chemical synthesis of Li₂TCNQF₄. Attempts to prepare a single crystal of Li₂TCNQF₄ have been unsuccessful, although air-stable (Pr₄N)₂TCNQF₄ was obtained by mixing Pr₄NBr with Li₂TCNQF₄ in aqueous solution. Pr₄NTCNQF₄ was also obtained by reaction of LiTCNQF₄ with Pr₄NBr in water. Li₂TCNQF₄, (Pr₄N)₂TCNQF₄, and Pr₄NTCNQF₄ have been characterized by UV–vis, FT-IR, Raman, and NMR spectroscopy, high resolution electrospray ionization mass spectrometry, and electrochemistry. The structures of single crystals of (Pr₄N)₂TCNQF₄ and Pr₄NTCNQF₄ have been determined by X-ray crystallography. These TCNQF₄^2– salts will provide useful precursors for the synthesis of derivatives of the dianions