Comparing Perceptions of Conflict Mediation Strategies between School Administrators and Non-Administrators

Prior research has explored the impact of conflict mediation practices in schools, regarding students’ perceptions, but existing research has not examined how principals and other school staff members perceive these practices. Given the significant shift away from zero tolerance and towards more restorative practices such as conflict mediation, the current study seeks to examine if school administrators and non-administrators differ in their perceptions of the value of conflict mediation, perceptions of existing conflict mediation skills, and perceptions of the effects of current practices on school climate, as perceptions can influence how information is applied. As these two groups have their own distinct interactions with students, it is hypothesized that they will have differing opinions regarding the instruction and implementation of these conflict mediation techniques. Data were collected from 150 school staff members (108 administrators, 42 non-administrators) from the School District of Philadelphia prior to a professional development training; participants completed a survey assessing perceptions of conflict mediation. School staff were categorized post hoc as administrators or non-administrators based on their self-identification within the survey. A chi-square analysis and three separate multivariate analysis of variance were conducted. Analyses revealed that the two groups did not differ in their experience with conflict mediation, perceptions of the value of conflict mediation, perceptions of their existing mediation skills, or perceptions of the effects of the current practices on school climate. Therefore, school administrators and non-administrators can continue to receive the same training, as long as they maintain similar perceptions regarding these strategies. These findings have implications for current practices, both in terms of designing future mediation trainings, as well as applying these skills within schools.M.S., Psychology -- Drexel University, 201

Aryl amino acetamides prevent Plasmodium falciparum ring development via targeting the lipid-transfer protein PfSTART1.

With resistance to most antimalarials increasing, it is imperative that new drugs are developed. We previously identified an aryl acetamide compound, MMV006833 (M-833), that inhibited the ring-stage development of newly invaded merozoites. Here, we select parasites resistant to M-833 and identify mutations in the START lipid transfer protein (PF3D7_0104200, PfSTART1). Introducing PfSTART1 mutations into wildtype parasites reproduces resistance to M-833 as well as to more potent analogues. PfSTART1 binding to the analogues is validated using organic solvent-based Proteome Integral Solubility Alteration (Solvent PISA) assays. Imaging of invading merozoites shows the inhibitors prevent the development of ring-stage parasites potentially by inhibiting the expansion of the encasing parasitophorous vacuole membrane. The PfSTART1-targeting compounds also block transmission to mosquitoes and with multiple stages of the parasite's lifecycle being affected, PfSTART1 represents a drug target with a new mechanism of action

Teacher- and Child-perceived Relationship Quality in Upper Elementary School and Child Academic and Behavioral Outcomes

The quality of the relationship that children form with their classroom teachers during their preschool and formal schooling years has significant implications for their developmental outcomes. Specifically, teacher-child relationship quality influences children’s later school success, with relationship problems as early as kindergarten predicting poor academic performance in eighth grade. The influence of teacher-child relationships on children’s social-emotional and behavioral outcomes has also been examined to a lesser extent. Elevated levels of teacher-child conflict have been found to predict aggression, whereas relationship closeness predicts higher social competence. However, research to date has primarily focused on preschool and kindergarten-aged students and has relied largely upon teacher-reported relationship quality, with comparatively less research on relationship quality in the upper elementary grades, and how children’s perceptions of the relationship are associated with their academic and behavioral development. Few studies have simultaneously examined teacher-child relationship quality as perceived both by teachers and children, and whether their respective perceptions are associated with children’s academic and behavioral outcomes to similar or different degrees, and whether they are differentially related to these outcomes for children at elevated levels of academic or behavioral risk. Using a sample of 334 third and fourth grade teachers and their 5,112 students, the current study seeks to examine how teachers’ and children’s perceptions of closeness in their relationship in the middle of the academic year predicts children’s academic and behavioral outcomes at the end of the year, and whether these associations are moderated by initial academic and behavioral risk statuses. High reports of relationship closeness by children and their teachers were found to significantly predict child ELA and Math achievement, with child behavioral risk significantly moderating both academic outcomes. Within-reporter effects were found for the direct effects of teacher and child closeness on teacher- and child-reported aggression, respectively; teacher-reported closeness also significantly predicted child reports of aggressive behavior when moderated by behavioral risk. Although a cross-reporter effect was detected for child-reported closeness on teacher-reported social competence, no significant moderations were found. Child reports of the relationship should be equally considered when assessing teacher-child relationship quality and child outcomes, especially in behaviorally at-risk children

Sulfonylpiperazine compounds prevent Plasmodium falciparum invasion of red blood cells through interference with actin-1/profilin dynamics.

With emerging resistance to frontline treatments, it is vital that new antimalarial drugs are identified to target Plasmodium falciparum. We have recently described a compound, MMV020291, as a specific inhibitor of red blood cell (RBC) invasion, and have generated analogues with improved potency. Here, we generated resistance to MMV020291 and performed whole genome sequencing of 3 MMV020291-resistant populations. This revealed 3 nonsynonymous single nucleotide polymorphisms in 2 genes; 2 in profilin (N154Y, K124N) and a third one in actin-1 (M356L). Using CRISPR-Cas9, we engineered these mutations into wild-type parasites, which rendered them resistant to MMV020291. We demonstrate that MMV020291 reduces actin polymerisation that is required by the merozoite stage parasites to invade RBCs. Additionally, the series inhibits the actin-1-dependent process of apicoplast segregation, leading to a delayed death phenotype. In vitro cosedimentation experiments using recombinant P. falciparum proteins indicate that potent MMV020291 analogues disrupt the formation of filamentous actin in the presence of profilin. Altogether, this study identifies the first compound series interfering with the actin-1/profilin interaction in P. falciparum and paves the way for future antimalarial development against the highly dynamic process of actin polymerisation

Resistant genomes pooled variant summary.

With emerging resistance to frontline treatments, it is vital that new antimalarial drugs are identified to target Plasmodium falciparum. We have recently described a compound, MMV020291, as a specific inhibitor of red blood cell (RBC) invasion, and have generated analogues with improved potency. Here, we generated resistance to MMV020291 and performed whole genome sequencing of 3 MMV020291-resistant populations. This revealed 3 nonsynonymous single nucleotide polymorphisms in 2 genes; 2 in profilin (N154Y, K124N) and a third one in actin-1 (M356L). Using CRISPR-Cas9, we engineered these mutations into wild-type parasites, which rendered them resistant to MMV020291. We demonstrate that MMV020291 reduces actin polymerisation that is required by the merozoite stage parasites to invade RBCs. Additionally, the series inhibits the actin-1-dependent process of apicoplast segregation, leading to a delayed death phenotype. In vitro cosedimentation experiments using recombinant P. falciparum proteins indicate that potent MMV020291 analogues disrupt the formation of filamentous actin in the presence of profilin. Altogether, this study identifies the first compound series interfering with the actin-1/profilin interaction in P. falciparum and paves the way for future antimalarial development against the highly dynamic process of actin polymerisation.</div

MMV291 analogues interfere with actin polymerisation in the presence of profilin in vitro.

PfACT1 (4 μM) under polymerizing conditions was quantified in the supernatant and pellet fractions in the presence of the MMV291 analogues (25 μM) or DMSO and upon addition of PfPFN (16 μM). (A) In the absence of PfPFN, 80 ± 4% of PfACT1 sedimented to the pellet fraction with the vehicle DMSO treatment. S-W936 decreased the amount of actin in the pellet to 68 ± 7%, while the remaining compounds had no significant effects on actin sedimentation. (B) Upon addition of PfPFN, actin sedimentation decreased to 21 ± 1% with DMSO treatment. All MMV291 analogues, S-MMV291, R-MMV291, S-W936, R-W936, S-W414, and S-W827, decreased the amount of actin in the pellet further to 11 ± 1%, 15 ± 2%, 8 ± 2%, 10 ± 4%, 9 ± 4%, and 5 ± 2%, respectively. Results are plotted as mean ± standard deviation of the relative amounts of actin in the pellet fraction. The data are based on at least 3 independent assays each performed in triplicate. Statistical significances were determined using an unpaired two-tailed t test, where ** P ≤ 0.01 and *** P ≤ 0.001, and **** ≤ 0.0001. No bar indicates not significant. Source data can be found in S1 Data.</p

A model of the comparison between mutation locations in human and <i>P</i>. <i>falciparum</i>.

An X-ray structure human profilin (gold) (PDB: 2PBD) and a homology model of human actin (green) (created by SWISS-MODEL [106] using O. cuniculus actin (PDB: 2PBD) [56] aligned with P. falciparum profilin (pink) (PDB: 2JKG) [36] and actin (blue) (PDB: 6I4E) [42] showing the similarity of the heterodimeric complex. The positions of the MMV291 P. falciparum mutations and the associated human amino acids are shown for comparison. (TIF)</p

Proposed model for MMV291 interference in profilin-mediated filamentous actin polymerisation.

(A) Treadmilling model of profilin’s role in sequestering G-actin and stimulating the exchange of ADP for ATP before delivering the subunits to the barbed end of the growing filament. Here, formin initiates the polymerisation process to form F-actin. Hydrolysis of the G-actin-ATP occurs at this end to produce G-actin-ADP and inorganic phosphate (Pi), to stabilise the filament. The slow release of Pi at the pointed end induces filament instability and proteins such as ADF1 bind to G-actin-ADP to aid in the release of the subunits, thereby severing the filaments. (B) A potential mechanism for MMV291’s inhibitory activity could be through the stabilisation of the G-actin/profilin dimer therefore inhibiting the formation of F-actin and preventing the generation of force required for invasion. ADF1, actin depolymerising factor 1; F-actin, filamentous actin; G-actin, globular actin.</p

Source data for graphs in this paper.

With emerging resistance to frontline treatments, it is vital that new antimalarial drugs are identified to target Plasmodium falciparum. We have recently described a compound, MMV020291, as a specific inhibitor of red blood cell (RBC) invasion, and have generated analogues with improved potency. Here, we generated resistance to MMV020291 and performed whole genome sequencing of 3 MMV020291-resistant populations. This revealed 3 nonsynonymous single nucleotide polymorphisms in 2 genes; 2 in profilin (N154Y, K124N) and a third one in actin-1 (M356L). Using CRISPR-Cas9, we engineered these mutations into wild-type parasites, which rendered them resistant to MMV020291. We demonstrate that MMV020291 reduces actin polymerisation that is required by the merozoite stage parasites to invade RBCs. Additionally, the series inhibits the actin-1-dependent process of apicoplast segregation, leading to a delayed death phenotype. In vitro cosedimentation experiments using recombinant P. falciparum proteins indicate that potent MMV020291 analogues disrupt the formation of filamentous actin in the presence of profilin. Altogether, this study identifies the first compound series interfering with the actin-1/profilin interaction in P. falciparum and paves the way for future antimalarial development against the highly dynamic process of actin polymerisation.</div

MMV291 pretreatment of uninfected RBCs does not inhibit merozoite invasion.

Uninfected RBCs were pretreated with invasion inhibitory compounds (blue); 10 μM MMV291, 100 μg/mL heparin, 2 μM cytochalasin D (CytD), or 0.0025% glutaraldehyde (Glut) for 30 minutes at 37°C, after which the cells were washed (W/O) to remove the inhibitors. Purified merozoites were then allowed to invade the pretreated RBCs. In parallel, merozoites were added to untreated RBCs in the presence of these inhibitors (red). After incubation for 30 minutes at 37°C, the compounds were washed out and parasites allowed to grow for 24 hours. Successful invasion was assessed by measuring the bioluminescence levels of trophozoite-stage parasites expressing a nanoluciferase reporter, and invasion rate was normalised to the DMSO vehicle control. This demonstrated that unlike the fixative glutaraldehyde, pretreatment with MMV291 did not reduce merozoite invasion of RBCs, producing a similar profile to the invasion inhibitory molecules, heparin and CytD. Error bars represent the standard deviation of 2 biological replicates with statistical analyses performed in GraphPad Prism using a one-way ANOVA with pretreated RBCs compared to glutaraldehyde (blue) and merozoite treatment compared to heparin (red). **** indicates P P > 0.05). Source data can be found in S1 Data. (TIF)</p