Dynamics of DNA repair enzymes and competence proteins in Bacillus subtilis

DNA double strand breaks (DSBs) are a severe threat to genome integrity and thus a variety of proteins are dedicated to repair such threats. The major repair route in bacteria is that of homologous recombination (HR), with the ATPase RecA as a key player. In HR, a broken DNA strand is repaired using a second intact DNA copy present on a homologous chromosome. This process involves the exchange of DNA strands, mediated by RecA, which forms filamentous polymers on ssDNA and initiates strand exchange. Prior to RecA, a plethora of Rec-proteins (Rec NJORFX) act to initiate HR. In Bacillus subtilis this process starts with RecN forming foci 15 minutes after DSB induction and is finished when RecA filaments disassemble and cell growth resumes after three hours. I wished to obtain a more detailed view on the dynamics of these proteins, and therefore employed single molecule fluorescence microscopy in live cells. Using 40 ms stream acquisition, I detected the movement of single Rec proteins and analyzed these trajectories mathematically. In exponentially growing cells I observed that RecN, RecO and, partially, RecJ continuously scan the nucleoid, supporting a distributive search model of individual molecules. In contrast to RecN and RecO, a fraction of the exonuclease RecJ is retained at the replication machinery. Upon induction of DSBs, RecNJO arrest at several sites on the nucleoid. RecN does not form static repair centers as proposed for eukaryotes, but short-lived (~2.5 s) clusters that act as repair enzyme recruitment platforms. Thus the local concentration of Rec-proteins increases to trap interaction partners out of a pool of diffusive enzymes. A majority of the RecNJO molecules keep on scanning for lesions or interaction partners, even in the presence of DSBs. In toto, my work indicates that the initial detection of a DSB, processing of free DNA ends, and loading of RecA on the generated ssDNA site takes place in a very short time frame, performed by a minority of the protein population

Rural High School Libraries: Places Prone to Promote Positive School Climates

The multiple case study (Flyvbjerg, 2011; Stake, 2006) of three new rural high school libraries, located in two states in the U.S. Midwest, and the school communities they serve are part of a long-term research agenda grounded in a critical perspective (Anderson, 1989) and devoted to deepening the understanding of the relationships between teenagers’ student peer culture, in the U.S. commonly perceived as intrinsically problematic, and the contributions of informal learning environments and non-classroom spaces (NCS) to school social climate (Voight & Nation, 2016). We found that school libraries are places prone to promote positive school climates

The spaces in between at Orbit High : an analysis of teenage behavior during breaks at school /

Includes vita.Most public schools in the United States were designed and built in the second half of the last century. Their buildings typically consist of classrooms and narrow, locker-lined hallways. The former clearly belong to the teachers and best support lecturestyle instruction. The latter are the locations for social interaction between students during their breaks. Many educators, administrators, and researchers worry about teenage behavior in high schools. Student peer culture is commonly understood as problematic. In response, break times typically are minimized, supervision routines are designed to be seamless, and educational policies regulate disciplinary institutional responses to acts of violence between students. This research study investigates teenagers' break behavior in a contemporary school building that is unlike the institutional school buildings most current educators are used to and experience as "normal". The ethnographic case examines the relationships between high school student break behavior, local disciplinary practices, and a school building designed to blur the boundaries between lounge-like social spaces and informal educational spaces. Over the course of six months, the researcher spent 42 school days with Orbit High's teenagers in the spaces in between. Primary sources of data were field notes, log entries, behavioral maps, and open-ended interviews with 24 purposefully chosen participants.Dr. Benyamin Schwarz, Dissertation Supervisor.|Includes vita.Includes bibliographical references (pages 181-200)

The neuromuscular system of <i>Pycnophyes kielensis</i> (Kinorhyncha: Allomalorhagida) investigated by confocal laser scanning microscopy

Abstract Background Kinorhynchs are ecdysozoan animals with a phylogenetic position close to priapulids and loriciferans. To understand the nature of segmentation within Kinorhyncha and to infer a probable ancestry of segmentation within the last common ancestor of Ecdysozoa, the musculature and the nervous system of the allomalorhagid kinorhynch Pycnophyes kielensis were investigated by use of immunohistochemistry, confocal laser scanning microscopy, and 3D reconstruction software. Results The kinorhynch body plan comprises 11 trunk segments. Trunk musculature consists of paired ventral and dorsal longitudinal muscles in segments 1–10 as well as dorsoventral muscles in segments 1–11. Dorsal and ventral longitudinal muscles insert on apodemes of the cuticle inside the animal within each segment. Strands of longitudinal musculature extend over segment borders in segments 1–6. In segments 7–10, the trunk musculature is confined to the segments. Musculature of the digestive system comprises a strong pharyngeal bulb with attached mouth cone muscles as well as pharyngeal bulb protractors and retractors. The musculature of the digestive system shows no sign of segmentation. Judged by the size of the pharyngeal bulb protractors and retractors, the pharyngeal bulb, as well as the introvert, is moved passively by internal pressure caused by concerted action of the dorsoventral muscles. The nervous system comprises a neuropil ring anterior to the pharyngeal bulb. Associated with the neuropil ring are flask-shaped serotonergic somata extending anteriorly and posteriorly. A ventral nerve cord is connected to the neuropil ring and runs toward the anterior until an attachment point in segment 1, and from there toward the posterior with one ganglion in segment 6. Conclusions Segmentation within Kinorhyncha likely evolved from an unsegmented ancestor. This conclusion is supported by continuous trunk musculature in the anterior segments 1–6, continuous pharyngeal bulb protractors and retractors throughout the anterior segments, no sign of segmentation within the digestive system, and the absence of ganglia in most segments. The musculature shows evidence of segmentation that fit the definition of an anteroposteriorly repeated body unit only in segments 7–10

Maternal Gatekeeping: Do They See It The Way We Do?

Research on father-child relationships has increased because father involvement has a positive influence on the child’s social, behavioral, and psychological outcomes. One of the largest influences on father involvement in childrearing may be mothers’ beliefs and behaviors. In other words, mothers may act as ‘gatekeepers’ by controlling the father’s interaction with the child. Previous research on maternal gatekeeping has mainly used self-reports and has made few attempts to validate these measures. The present study used observational measures of maternal gatekeeping behavior, and compared observations and self-reports of maternal gatekeeping. This study also considered predictors of observed maternal gatekeeping behavior and compared them to predictors of self-reports of maternal gatekeeping. Participants were 182 dual-earner couples who partook in a longitudinal study of first-time parents. To assess predictors of maternal gatekeeping behavior, I examined parents’ psychological well-being, gender role beliefs, and contextual factors from questionnaire data collected at the third trimester of pregnancy, 3 and 9 months postpartum. At 9 months postpartum, observations of maternal gatekeeping behavior were coded from videotaped mother-father-infant interaction episodes, and mothers’ and fathers’ questionnaire reports of maternal gatekeeping behavior were also obtained. Pearson correlations were used to examine if parents’ perceptions of maternal gatekeeping behavior were consistent with observations of maternal gatekeeping. Pearson correlations were also used to determine the parent characteristics that were associated with observed and reported maternal gatekeeping. Results showed modest associations between observations and self-reports of gatekeeping. Results also indicate associations of mothers’ psychological well- being and parents’ gender role beliefs with observed maternal gatekeeping behavior. Specifically, a significant correlation was found between observed gate closing and self-reports of gate closing. Also, mothers who reported themselves higher on gate closing behavior reported themselves higher on perfectionism, depression, and benevolent sexism but lower on life satisfaction. Stronger levels of reported hostile sexism and beliefs about the natural superiority of women as mothers were also associated with higher levels of gate closing. Future research should examine gatekeeping behavior across various contexts.The New Parents Project is supported by the NSF (CAREER 0746548 to Schoppe-Sullivan), NICHD (K01HD056238 to Kamp Dush), Ohio State University’s Initiative in Population Research, also supported by NICHD (R24-HD058484), and the Department of Human Development and Family Science. Portions of this paper were presented at the 2011 Society for Research in Child Development annual meeting in Montréal, Canada.Funding was also provided from the University Honors and Scholars Center and the College of Education and Human Ecology in the form of a Full Undergraduate Research Scholarship.Funding was also provided in the form of a Summer Research Scholarship from the University Honors and Scholars Center.No embarg

Determining the competitive nature of physical therapy education: A multi case study design

Higher education is becoming more competitive as for-profit and non-profit institutions continue to expand. Healthcare educational programs, such as physical therapy, find themselves competing for quality applicants. Understanding this competitive environment and how to thrive within is critical for program survival. The purpose of this study was to determine the competitive strategies being used by entry-level doctorate programs in physical therapy; Eight physical therapy programs, ranked in the top 15% of schools, were purposively selected for the study. Four of the programs were private institutions represented by the University of Southern California (USC), University of Miami, Northwestern University, and Creighton University. The four public campuses include Northern Arizona University (NAU), University of Iowa, University of Nebraska, Omaha (UNMC), and University of Illinois-Chicago (UIC); A qualitative, multi case design was used to evaluate the variances in competitive strategy. Programs were assessed through documented materials faculty interviews, and site assessments. Data from all three sources were triangulated revealing twelve consistent categories. A cross comparison of programs was performed assessing presence of competitive strategies; Competitive advantage can be gained through cost leadership, differentiation, and/or focus. The four public institutions (average cost of {dollar}29,500) demonstrate a significant cost leadership advantage when compared to the private institutions ({dollar}81,250). Campus and program orientation revealed significant program differentiation relative to Carnegie Classification, supportive programs, and institutional environment. Specifically, significant differentiation was noted for five research extensive institutions. In addition, the presence of a PhD program and a medical campus location were also distinguishing features. USC and Iowa exhibited all three differentiation elements. All eight programs exhibited some level of focus. Miami revealed a cost leadership focus. Each of the four public programs demonstrated significant differentiated focus through program delivery while the four private schools had a strong curricular design and recruitment focus; Although there is some overlap, institutional type fosters differences in competitive strategy. Public institutions have a significant cost leadership position that when combined with perceived value can result in a strong competitive position. These four public programs create value by taking advantage of their educational environment and providing exceptional educational delivery. In contrast, the four private programs must combat the impact of cost by creating a differentiated educational environment. The four programs in this study have combined multiple elements, such as curricular design, medical environment and research to create a perceived value that exceeds normal student expectation

The initial effects of the treatment of Class II, division 1 malocclusions with the van Beek activator compared with the effects of the Herren activator and an activator-headgear combination

The effects of the van Beek activator in the correction of Class II, division 1 malocclusions were studied in 39 children, aged 9-13 years (median 11 years), and compared with the effects of treatment with an activator according to Herren and with those of an activator-headgear combination. Profile cephalograms were made before treatment and at the attainment of a Class I molar relationship (median observation time 9 months). The median improvement of the overjet was 4.7 mm and of the molar relationship 3.6 mm. This was largely achieved skeletally by an increase in mandibular prognathism while the skeletal effect on the maxilla was clinically insignificant. The maxillary incisors retroclined and the mandibular incisors proclined moderately. In general, no intrusion of the maxillary incisors was found and the eruption of the molars could not be stopped. The effects differed partly between the sexes, with a larger mandibular skeletal and molar reaction in boys, and a larger maxillary molar movement in girls. The larger mandibular reaction in the boys might have been due to the on average 4.5 months longer treatment time. The skeletal effects of the treatment were similar with all three activator types. The control of the incisors was, however, superior with the van Beek activator, especially when compared with the Herren activato