Violence against children perpetrated by peers: A cross-sectional school-based survey in Uganda

Violence against children by peers is a global public health problem. We aimed to assess factors associated with peer violence victimization among primary school children in Uganda. We conducted multilevel multivariable logistic regression analyses of cross-sectional data from 3706 primary students in 42 Ugandan primary schools. Among primary school students, 29% and 34% had ever experienced physical and emotional violence perpetrated by their peers, respectively. Factors strongly associated with both physical and emotional violence were similar and overlapping, and included exposure to interparental violence, having an attitude supportive of violence against children from school staff, not living with biological parents, working for payment, and higher SDQ score. However, we found that younger age, sharing sleeping area with an adult and achieving a higher educational performance score, were specifically associated with physical violence. On the other hand, being female, walking to school, reporting disability and eating one meal on the previous day, were particularly associated with emotional violence. Interventions to reduce peer violence should focus on family contexts, school environments and those with poor socio-economic status may need extra support

How did the Good School Toolkit reduce the risk of past week physical violence from teachers to students? Qualitative findings on pathways of change in schools in Luwero, Uganda.

Violence against children is a serious violation of children's rights with significant impacts on current and future health and well-being. The Good School Toolkit (GST) is designed to prevent violence against children in primary schools through changing schools' operational cultures. Conducted in the Luwero District in Uganda between 2012 and 2014, findings from previous research indicate that the Toolkit reduced the odds of past week physical violence from school staff (OR = 0.40, 95%CI 0.26-0.64, p < 0.001), corresponding to a 42% reduction in risk of past week physical violence. This nested qualitative study involved 133 interviews with students, teachers, school administration, and parents, and two focus group discussion with teachers. Interviews were conducted using semi-structured tools and analysed using thematic analysis complemented by constant comparison and deviant case analysis techniques. Within a context of normative acceptance of corporal punishment this qualitative paper reports suggestive pathways related to teacher-student relationships through which reductions in violence operated. First, improved student-teacher relationships resulted in improved student voice and less fear of teachers. Second, the intervention helped schools to clarify and encourage desired behaviour amongst students through rewards and praise. Third, many teachers valued positive discipline and alternative discipline methods, including peer-to-peer discipline, as important pathways to reduced use of violence. These shifts were reflected in changes in the views, use, and context of beating. Although the GST is effective for reducing physical violence from teachers to students, violence persisted, though at significantly reduced levels, in all schools with reductions varying across schools and individuals. Much of the success of the Toolkit derives from the support it provides for fostering better student-teacher relationships and alternative discipline options. Such innovation could usefully be incorporated in teacher training syllabi to equip teachers with knowledge and skills to maintain discipline without the use of fear or physical punishment

Heterologous Stop Codon Readthrough of Metazoan Readthrough Candidates in Yeast

Recent analysis of genomic signatures in mammals, flies, and worms indicates that functional translational stop codon readthrough is considerably more abundant in metazoa than previously recognized, but this analysis provides only limited clues about the function or mechanism of readthrough. If an mRNA known to be read through in one species is also read through in another, perhaps these questions can be studied in a simpler setting. With this end in mind, we have investigated whether some of the readthrough genes in human, fly, and worm also exhibit readthrough when expressed in S. cerevisiae. We found that readthrough was highest in a gene with a post-stop hexamer known to trigger readthrough, while other metazoan readthrough genes exhibit borderline readthrough in S. cerevisiae.National Institutes of Health (U.S.) (5U54HG004555-03

Effect of the good school toolkit on school staff mental health, sense of job satisfaction and perceptions of school climate: Secondary analysis of a cluster randomised trial

The Good School Toolkit, a complex behavioural intervention delivered in Ugandan primary schools, has been shown to reduce school staff-perpetrated physical violence against students. We aimed to assess the effect of this intervention on staff members' mental health, sense of job satisfaction and perception of school climate. We analysed data from a cluster-randomised trial administered in 42 primary schools in Luwero district, Uganda. The trial was comprised of cross-sectional baseline (June/July 2012) and endline (June/July 2014) surveys among staff and students. Twenty-one schools were randomly selected to receive the Toolkit, whilst 21 schools constituted a wait-listed control group. We generated composite measures to assess staff members' perceptions of the school climate and job satisfaction. The trial is registered at clinicaltrials.gov (NCT01678846). No schools dropped out of the study and all 591 staff members who completed the endline survey were included in the analysis. Staff in schools receiving the Toolkit had more positive perspectives of their school climate compared to staff in control schools (difference in mean scores 2.19, 95% Confidence Interval 0.92, 3.39). We did not find any significant differences for job satisfaction and mental health. In conclusion, interventions like the Good School Toolkit that reduce physical violence by school staff against students can improve staff perceptions of the school climate, and could help to build more positive working and learning environments in Ugandan schools

A Mathematical Model of Liver Cell Aggregation In Vitro

The behavior of mammalian cells within three-dimensional structures is an area of intense biological research and underpins the efforts of tissue engineers to regenerate human tissues for clinical applications. In the particular case of hepatocytes (liver cells), the formation of spheroidal multicellular aggregates has been shown to improve cell viability and functionality compared to traditional monolayer culture techniques. We propose a simple mathematical model for the early stages of this aggregation process, when cell clusters form on the surface of the extracellular matrix (ECM) layer on which they are seeded. We focus on interactions between the cells and the viscoelastic ECM substrate. Governing equations for the cells, culture medium, and ECM are derived using the principles of mass and momentum balance. The model is then reduced to a system of four partial differential equations, which are investigated analytically and numerically. The model predicts that provided cells are seeded at a suitable density, aggregates with clearly defined boundaries and a spatially uniform cell density on the interior will form. While the mechanical properties of the ECM do not appear to have a significant effect, strong cell-ECM interactions can inhibit, or possibly prevent, the formation of aggregates. The paper concludes with a discussion of our key findings and suggestions for future work

A Viable Hypomorphic Allele of the Essential IMP3 Gene Reveals Novel Protein Functions in Saccharomyces cerevisiae

In Saccharomyces cerevisiae, the essential IMP3 gene encodes a component of the SSU processome, a large ribonucleoprotein complex required for processing of small ribosomal subunit RNA precursors. Mutation of the IMP3 termination codon to a sense codon resulted in a viable mutant allele producing a C-terminal elongated form of the Imp3 protein. A strain expressing the mutant allele displayed ribosome biogenesis defects equivalent to IMP3 depletion. This hypomorphic allele represented a unique opportunity to investigate and better understand the Imp3p functions. We demonstrated that the +1 frameshifting was increased in the mutant strain. Further characterizations revealed involvement of the Imp3 protein in DNA repair and telomere length control, pointing to a functional relationship between both pathways and ribosome biogenesis

Statistical Analysis of Readthrough Levels for Nonsense Mutations in Mammalian Cells Reveals a Major Determinant of Response to Gentamicin

The efficiency of translation termination depends on the nature of the stop codon and the surrounding nucleotides. Some molecules, such as aminoglycoside antibiotics (gentamicin), decrease termination efficiency and are currently being evaluated for diseases caused by premature termination codons. However, the readthrough response to treatment is highly variable and little is known about the rules governing readthrough level and response to aminoglycosides. In this study, we carried out in-depth statistical analysis on a very large set of nonsense mutations to decipher the elements of nucleotide context responsible for modulating readthrough levels and gentamicin response. We quantified readthrough for 66 sequences containing a stop codon, in the presence and absence of gentamicin, in cultured mammalian cells. We demonstrated that the efficiency of readthrough after treatment is determined by the complex interplay between the stop codon and a larger sequence context. There was a strong positive correlation between basal and induced readthrough levels, and a weak negative correlation between basal readthrough level and gentamicin response (i.e. the factor of increase from basal to induced readthrough levels). The identity of the stop codon did not affect the response to gentamicin treatment. In agreement with a previous report, we confirm that the presence of a cytosine in +4 position promotes higher basal and gentamicin-induced readthrough than other nucleotides. We highlight for the first time that the presence of a uracil residue immediately upstream from the stop codon is a major determinant of the response to gentamicin. Moreover, this effect was mediated by the nucleotide itself, rather than by the amino-acid or tRNA corresponding to the −1 codon. Finally, we point out that a uracil at this position associated with a cytosine at +4 results in an optimal gentamicin-induced readthrough, which is the therapeutically relevant variable

Stereochemical Basis for Engineered Pyrrolysyl-tRNA Synthetase and the Efficient in Vivo Incorporation of Structurally Divergent Non-native Amino Acids

bS Supporting Information Incorporation of Uaas into proteins using a host’s endogenoustranslation machinery opens the door to addressing questions with chemical precision that is unattainable using naturally occurring amino acids. This expanded toolset allows one to pose and answer more in-depth molecular questions without the limitations imposed by the 20 natural amino acids used in traditional mutagenic analyses.1,2 Aminoacyl-tRNA synthetases (RSs) obtained by structure-based engineering and directed evolution efficiently recognize and activate Uaas through ATP-dependent adenylation and subsequently catalyze transfer to their cognate tRNA. To date, more than 70 Uaas are now amenable to translational insertion into proteins in bacteria, yeast, or mammalian cells using these artificially evolved tRNA/ RS pairs.3 By choosing particular matching sets of tRNA/RSs from diverse organisms, the pairs can function in vivo in a

Genetic Basis of Hidden Phenotypic Variation Revealed by Increased Translational Readthrough in Yeast

Eukaryotic release factors 1 and 3, encoded by SUP45 and SUP35, respectively, in Saccharomyces cerevisiae, are required for translation termination. Recent studies have shown that, besides these two key factors, several genetic and epigenetic mechanisms modulate the efficiency of translation termination. These mechanisms, through modifying translation termination fidelity, were shown to affect various cellular processes, such as mRNA degradation, and in some cases could confer a beneficial phenotype to the cell. The most studied example of such a mechanism is [PSI+], the prion conformation of Sup35p, which can have pleiotropic effects on growth that vary among different yeast strains. However, genetic loci underlying such readthrough-dependent, background-specific phenotypes have yet to be identified. Here, we used sup35C653R, a partial loss-of-function allele of the SUP35 previously shown to increase readthrough of stop codons and recapitulate some [PSI+]-dependent phenotypes, to study the genetic basis of phenotypes revealed by increased translational readthrough in two divergent yeast strains: BY4724 (a laboratory strain) and RM11_1a (a wine strain). We first identified growth conditions in which increased readthrough of stop codons by sup35C653R resulted in different growth responses between these two strains. We then used a recently developed linkage mapping technique, extreme QTL mapping (X-QTL), to identify readthrough-dependent loci for the observed growth differences. We further showed that variation in SKY1, an SR protein kinase, underlies a readthrough-dependent locus observed for growth on diamide and hydrogen peroxide. We found that the allelic state of SKY1 interacts with readthrough level and the genetic background to determine growth rate in these two conditions

Assessment of Inactivating Stop Codon Mutations in Forty Saccharomyces cerevisiae Strains: Implications for [PSI+] Prion- Mediated Phenotypes

The yeast prion [PSI+] has been implicated in the generation of novel phenotypes by a mechanism involving a reduction in translation fidelity causing readthrough of naturally occurring stop codons. Some [PSI+] associated phenotypes may also be generated due to readthrough of inactivating stop codon mutations (ISCMs). Using next generation sequencing we have sequenced the genomes of two Saccharomyces cerevisiae strains that are commonly used for the study of the yeast [PSI+] prion. We have identified approximately 26,000 and 6,500 single nucleotide polymorphisms (SNPs) in strains 74-D694 and G600 respectively, compared to reference strain S288C. In addition to SNPs that produce non-synonymous amino acid changes we have also identified a number of SNPs that cause potential ISCMs in these strains, one of which we show is associated with a [PSI+]-dependent stress resistance phenotype in strain G600. We identified twenty-two potential ISCMs in strain 74-D694, present in genes involved in a variety of cellular processes including nitrogen metabolism, signal transduction and oxidative stress response. The presence of ISCMs in a subset of these genes provides possible explanations for previously identified [PSI+]-associated phenotypes in this strain. A comparison of ISCMs in strains G600 and 74-D694 with S. cerevisiae strains sequenced as part of the Saccharomyces Genome Resequencing Project (SGRP) shows much variation in the generation of strain-specific ISCMs and suggests this process is possible under complex genetic control. Additionally we have identified a major difference in the abilities of strains G600 and 74-D694 to grow at elevated temperatures. However, this difference appears unrelated to novel SNPs identified in strain 74-D694 present in proteins involved in the heat shock response, but may be attributed to other SNP differences in genes previously identified as playing a role in high temperature growth