Cytokinesis is the final step in the cell cycle where one cell is physically divided into two. Animal and fungal cells perform cytokinesis with an actin- and myosin-based molecular machine, the contractile ring. A complete list of components in the contractile ring has been determined in the model organism Schizosaccharomyces pombe; however, it remains unknown how these components organize into a functional division apparatus. Here, I have investigated how the F-BAR family of proteins organizes upon the plasma membrane in the contractile ring. I found the Cdc15 F-BAR forms extended linear oligomers that stably bind the plasma membrane in the contractile ring. These oligomers robustly concentrate Cdc15 at the division site and contribute to anchoring the contractile ring in the cell middle. I found the Imp2 F-BAR, similar to previously studied F-BARs, forms oligomerizes in a helical fashion. Despite this fact, Imp2 does not rely upon oligomerization for its contractile ring function. I have also determined the precise spatial organization of 29 components of the contractile ring with super resolution microscopy, and constructed a nanoscale model of the contractile ring that may serve as a template for understanding the ringâs inner mechanics.

First impressions play a central role in human social interaction. In particular, the face is a rich source of information that perceivers use in making both initial and lasting character judgments. Despite the large and growing body of work demonstrating that these judgments affect outcomes in domains as crucial as elections and criminal sentencing, little remains known about the ontogenetic origins of this consequential aspect of human social cognition. The purpose of this dissertation is to provide a set of early investigations into the development of face-to-trait inferences. Paper 1 demonstrates that, like adults, even children as young as 3-4 years of age provide consistent trait judgments when asked to judge two-dimensional computer-generated face images, suggesting that this general ability is so fundamental as to emerge strongly at the earliest ages tested. Paper 2 shows that this propensity is so deeply ingrained at an early age that similar consensus across the lifespan emerges in response to static faces belonging to adults, children, and even rhesus macaques. Paper 3 investigates the potential consequences of these judgments, showing that face-based character assessments influence attributions of trait-relevant behaviors and even cause children to modulate their own behaviors towards others. The findings of this dissertation clearly illustrate that face-to-trait inference emerges early in development, and is therefore a fundamental element of human social cognition with important consequences throughout the lifespan. / Psychology

Humans can recognize others’ emotions based on overt cues such as facial expressions, affective vocalizations, or body posture, or by recruiting an abstract, causal theory of the conditions that tend to elicit different emotions. Whereas previous research has investigated the recognition of emotion in specific perceptual modalities (e.g. facial expressions), this dissertation focuses on the abstract representations that relate observable reactions to their antecedent causes. A combination of neuroimaging, behavioral, and developmental methods are used to shed light on the mechanisms that support various forms of emotion attribution, and to elucidate the core features or dimensions that structure the space of emotions we represent. Chapter 1 identifies brain regions that contain information about emotional valence conveyed either via facial expressions and or via animations depicting abstract situational information. These data reveal regions with modality-specific representations of emotional valence (i.e. patterns of activity that discriminate only positive versus negative facial expressions), as well as modality-independent representations: in medial prefrontal cortex (MPFC), the valence representation generalizes across stimuli, indicating a common neural code that abstracts away from specific perceptual features and is invariant to different forms of evidence. Building on evidence that young infants discriminate and respond to the emotional expressions of others, Chapter 2 investigates whether infants also represent these expressions in relation to the situations that elicit them. The results of several experiments demonstrate that infants within their first year of life have expectations about how facial and vocal displays of emotion relate to the valence of events that precede them. Whereas Chapters 1 and 2 focus on a simple binary distinction between positive and negative affect, Chapter 3 investigates a space of more fine-grained discriminations (e.g. someone feeling proud vs. grateful). A combination of multi- voxel pattern analyses and representational similarity analyses reveal brain regions containing abstract and high-dimensional representations of attributed emotion. Moreover, a set of causal features (encoding properties of eliciting events that vary between different emotions) outperforms more primitive dimensions in capturing neural similarities within these regions. Together, these studies provide a newly detailed characterization of the representations that structure emotion attribution, including their development and neural basis. / Psychology

This dissertation examines young children’s acceptance of, memory for, and doubts about counterintuitive claims. In Study 1, children aged 3- to 5-years in the United States and China were asked to categorize hybrids whose perceptual features originated from two different animals or two different objects (75% from one and 25% from the other). At first, most children categorized the hybrids in terms of their predominant perceptual features. However, after hearing counter-perceptual categorizations by an adult, children categorized fewer hybrids in terms of their predominant features. When retested 1-to 2-weeks later, the adult’s earlier counter-intuitive categorizations still impacted children’s categorizations but less strongly. In Study 2, American children aged 3- to 6-years were presented with three different-sized Russian dolls and asked to say which doll was the heaviest. Most children pointed to the biggest doll. They were then told that the smallest doll was the heaviest and that the biggest was the lightest, a claim that was false. Most children subsequently endorsed this claim. Nevertheless, when the experimenter left the room, older children were likely to check it by lifting the biggest and smallest dolls. Younger children rarely conducted such checks. In Study 3, Chinese preschool and elementary school children were presented with five different-sized Russian dolls and asked to indicate the heaviest doll. Half of the children then heard a false, counter-intuitive claim (i.e., smallest = heaviest). The remaining children heard a claim confirming their intuitions (i.e., biggest = heaviest). Again, most children endorsed the experimenter’s claim even when it was counter-intuitive. During the experimenter’s subsequent absence, elementary school children explored the dolls more if they had received counter-intuitive rather than confirming testimony. Preschool children rarely explored no matter what testimony they had received. On the experimenter’s return, children who had explored the dolls were likely to reject her counter-intuitive claim. Thus, counterintuitive claims can overturn children’s beliefs but their influence fades over time and is moderated by children’s opportunities to search for empirical evidence. Across two cultures, older children were more inclined than younger children to use opportunities to seek empirical evidence to check counterintuitive claims.

<p> The purpose of the current study was to investigate the dynamic process of disclosure within the adolescent&ndash;mother relationship by examining maternal characteristics that encourage adolescent disclosure of distressing experiences and risk factors that may interfere with mothers&rsquo; abilities to be supportive. A community sample of 66 mothers and their adolescent children (<i>M</i> = 14.31 years, 58% female) participated. The adolescents disclosed an emotionally distressing experience to their mothers for the first time.</p><p> Mothers&rsquo; validating behaviors and emotional distress in response to their adolescents&rsquo; expressions of negative emotion were predictive of adolescent disclosure. Adolescents who perceived their mothers to be validating of their negative emotions made more substantive disclosures and found disclosing to their mothers to be more beneficial. In contrast, greater maternal emotional distress was associated with less substantive disclosures, and maternal emotional distress was further indirectly associated with less substantive and beneficial disclosures through less maternal validation of negative emotion.</p><p> A developmental model of maternal risk for emotional distress in response to adolescent negative emotion was also supported. Maternal history of childhood trauma perpetrated by someone close to the mother (i.e., high betrayal) was associated with an increased likelihood of experiencing subsequent interpersonal trauma as an early adult; maternal interpersonal trauma in early adulthood was associated with mothers&rsquo; increased difficulty regulating their emotions; and greater maternal emotion dysregulation was associated with higher levels of maternal distress in response to adolescent negative emotion. An indirect association between maternal childhood high betrayal trauma and emotional distress was also supported through continued trauma and emotion regulation difficulties.</p><p> These findings suggest that when disclosing distressing experiences to their mothers, adolescents consider how validating their mothers are of their expression of negative emotion, as well as how distressing their emotions are for their mothers. Mothers&rsquo; histories of childhood trauma, ongoing interpersonal trauma in adulthood, and emotion regulation difficulties were further implicated in mothers&rsquo; reactions to their adolescents&rsquo; expressions of negative emotion. Interventions targeted to increase maternal emotion regulation skills and validation of children&rsquo;s negative emotions may be an effective way to promote better mother&ndash;adolescent communication, especially in regard to distressing experiences.</p><p>

<p> As adolescents transition to middle school, math confidence and performance declines (Eccles et al., 1993; Lee, Statuto, &amp; Kadar-Voivodas, 1983). These declines are typically attributed to social and maturational changes (Eccles, Lord, &amp; Midgley, 1991; Simmons &amp; Blyth, 1987). In this dissertation, I explore the hypothesis that low parent support for schoolwork is also responsible.</p><p> Latino-American adolescents are especially at risk for math difficulties. Maintaining adolescents&rsquo; engagement and performance in math are important goals for mothers because high levels of both are requisites for many professional careers. This dissertation will focus on Latino-American families to determine if mothers&rsquo; homework involvement is associated with changes in children&rsquo;s math-related outcomes across the transition to secondary school.</p><p> Parental involvement in math homework is assumed to mitigate declines in math performance during this transition. Cognitive models suggest that involved parents utilize scaffolding (Rogoff &amp; Gardner, 1984) and instruction to ensure math achievement (Pomerantz &amp; Moorman, 2010). Motivational models suggest that involved parents foster math engagement by bolstering child confidence, modeling management strategies, and promoting values that encourage children to work hard (Grolnick &amp; Slowiaczek, 1994; Simpkins, Fredricks, &amp; Eccles, 2015). However, empirical evidence in support of the importance of parents in math achievement is limited. While positive forms of involvement co-occur with better math outcomes (Bhanot &amp; Jovanovic, 2005; Rice et al., 2013), no studies have examined such associations longitudinally. Children who are uninterested in math may be more susceptible to the effects of parental homework involvement because they lack internal motivation for mastery that underlies performance in other children.</p><p> The present study examines the extent to which Latina-American mothers&rsquo; involvement in math homework is effective in preventing declines in child math-related outcomes (i.e., perceptions of math ability, etc) during the transition to middle school. Child math interest was postulated to moderate this association. Results indicated that low maternal homework involvement predicts worsening child math-related outcomes, but only for children who were intrinsically uninterested in math.</p><p> The findings hold important implications for parents, who must work to ensure that they remain engaged in their children&rsquo;s activities, especially if children appear uninterested in math.</p><p>

<p> Sperm mobility is a major determinant of male fertility in chicken. In spite of low heritability of reproductive traits, sperm mobility has high heritability index which suggests presence of quantitative trait loci (QTLs) governing the trait. Our research focused on three objectives: i) to identify the QTLs affecting low mobility phenotype in chicken, ii) to understand the impact of Sertoli-cells and germ cells interactions in influencing the mobility phenotype and iii) to identify the genes and gene networks differentially expressed in male and female PGCs. To detect the QTLs, genome wide association studies (GWAS) was conducted which revealed the presence of multiple minor alleles influencing the trait and indicated the role of epistasis. The second section of research involved isolation, culture and transfer of primordial germ cells (PGCs) to create high line germ line chimera chicken carrying low line PGCs. We established the culture of chicken PGCs isolated from the embryonic blood in a feeder free culture conditions but could not detect the presence of low line genotype in the semen of transgenic males. Our final study involved RNA-sequencing (RNAseq) of male and female PGCs to identify differentially expressed genes from their transcriptomes. We identified five candidate genes: 3-hydroxy-3-methylglutaryl CoA reductase (HMGCA), germ cell-less (GCL), SWIM (zinc finger SWIM domain containing transcription factor), SLC1A1 (solute carrier family 1 member 1), UBE2R2L (ubiquitin conjugating enzyme) and validated their expression level in male and female PGCs by RT-qPCR. GCL was exclusively expressed in males while SLC1A1 &amp; UBE2R2L were expressed only in female cPGCs. This present study provides novel gender specific germ cell markers in the broiler chicken. These results will help in elucidating the genetic programming of gender specific germ line development in broilers.</p><p>

This thesis developed and pilot tested the effectiveness of a psychosocial intervention, the Making Relationships Work (MRW) Workshop. The MRW has two aims. At the interpersonal level, MRW seeks to enhance the quality of the relationships of the adolescents who participate in the workshop. At the psychological level, MRW seeks to foster the development (or enhancement) of a sense of identity and intimacy among the adolescents who participate in the workshop. The MRW Workshops consist of a psychosocial group intervention that includes skills and knowledge development, perspective taking, and group experiential exercises. Subjects consisted of 26 late adolescents. A within-subjects design (pre-post-follow up) was used to assess the effectiveness, efficacy and utility of the MRW as measured by the Identity Domain Survey (IDS), SCL-90 (a psychological symptom distress checklist), Relationship Quality Scale (RQS), Relationship Closeness Inventory (RCI), Internal-External Locus of Control Measure (I-E), and two MRW Evaluation forms. One-way ANOVAs were performed with results indicating less distress ratings on the IDS and the SCL-90. No significant results were found on the RQS, RCI and I-E. Finally, the evaluation forms of the workshop revealed very positive ratings.

This dissertation tested the effectiveness of a psychosocial intervention, the Personal Development in the Context of Relationships (PDCR) program. The aim of the PDCR seeks to foster the development (or enhancement) of a sense of identity and intimacy among adolescents who participate in the program. The PDCR is a psychosocial group intervention which utilizes interpersonal relationship issues as a context to foster personal development in identity formation and facilitate the development of an individual's capacity for intimacy. The PDCR uses intervention strategies which include skills and knowledge development, experiential group exercises, and exploration for insight. Participants consisted of 1 10 late adolescents. A mixed-subjects design (prepost-follow up) was used to assess the effectiveness; efficacy and utility of the PDCR on the experimental condition relative to a content/social contact control group and a time control condition. Identity exploration and identity commitment were measured by the Ego Identity Process Questionnaire (EIPQ). Total intimacy and identity role satisfaction were measured by the Erikson Psychosocial Stage Inventory (EPSI). Relationship quality and closeness were measured by the Relationship Quality Scale (RQS) and the Relationship Closeness Inventory (RCI) in an effort to assess whether any potential impact on interpersonal relationships occurs. Mixed MANOVAs were used to analyze the data with results yielding significant values for increased total identity exploration from pre to post test and decreases in total identity commitment from pre to post to follow-up test in the experimental group relative to the control conditions on the EIPQ. Further results indicated increases in total intimacy from pre to post to follow-up test in the experimental group relative to the control conditions on the EPSI. No clear trends emerged from pre to post to follow-up test for the Relationship measures. Results are discussed in terms of both practical and theoretical implications.

The Notch and TGF13 signaling pathways have been shown to play important roles in regulating endothelial-to-mesenchymal transition (EndMT) during cardiac morphogenesis. EndMT is the process by which endocardial cells of the atrioventricular canal and the outflow tract repress endothelial cell phenotype and upregulate mesenchymal cell phenotype. EndMT is initiated by inductive signals emanating from the overlying myocardium and inter-endothelial signals and generate the cells that form the heart valves and atrioventricular septum. The Notch and TGFf3 pathway are thought to act in parallel to modulate endothelial phenotype and promote EndMT. Vascular endothelial (VE) cadherin is a key regulator of cardiac endothelial cell phenotype and must be downregulated during EndMT. Accordingly, VE-cadherin expression remains stabilized in the atrioventricular canal and outflow tract of Notchl-deficient mouse embryos, while activation of the Notch or TGFP pathways results in decreased VE-cadherin expression in endothelial cells. However, the downstream target gene(s) that are involved in regulating endothelial cell phenotype and VE-cadherin expression remain largely unknown. In this thesis the transcriptional repressor Slug is demonstrated to be expressed by the mesenchymal cells and a subset of endocardial cells of the atrioventricular canal and outflowtract during cardiac morphogenesis. Slug is demonstrated to be required for cardiac development through its role in regulating EndMT in the cardiac cushion. Data presented in Chapter 6 further suggests that Slug-deficiency in the mouse is compensated for by a increase in Snail expression after embryonic day (E) 9.5, which restores EndMT in the cardiac cushions. Additionally, the Notch pathway, via CSL, directly binds and regulates expression of the Slug promoter, while a close Slug family member, Snail is regulated by the TGFB pathway in endothelial cells. While Notch does not directly regulate Snail expression, Notch and TGFB act synergistically to regulate Snail expression in endothelial cells. It is further demonstrated that Slug is required for Notch mediated EndMT, binds to and represses the VE-cadherin promoter, and induces a motile phenotype. Collectively the data demonstrate that Notch signaling directly regulates Slug, but not Snail, expression and that the combined expression of Slug and Snail are required for cardiac cushion morphogenesis. / Medicine, Faculty of / Medicine, Department of / Experimental Medicine, Division of / Graduate