Regulation of the Salmonella typhimurium pepT gene

Thesis (B.S.)--Univeristy of Illinois at Urbana-Champaign, 1996.Includes bibliographical reference (leaves 44-50)U of I OnlyTheses restricted to UIUC community onl

Role for the BsSMC protein in chromosome organization and compaction

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Biology, 2002.Includes bibliographical references.All cells must compact their chromosomes in order for the DNA to fit inside the cell or nucleus. In Bacillus subtilis, and other bacteria, replication occurs simultaneously with the organization, compaction and segregation of newly duplicated chromosomal regions. My work indicates that the B. subtilis Structural Maintenance of Chromosomes (BsSMC) protein is involved in compacting and organizing the chromosome. Increasing the amount of supercoiling of DNA is a means to compact the chromosome. This thesis describes a role for BsSMC in supercoiling. I determined that BsSMC can alter the DNA topology of plasmids in vivo. There is also genetic evidence that BsSMC is involved in supercoiling. An smc null mutant is hypersensitive to inhibitors of DNA gyrase, which reduce the level of negative supercoiling in the cell. Conversely, depletion of Topoisomerase I, which increases the amount of negative supercoiling of the chromosome, partially suppresses the phenotype of an smc null mutant. These data are consistent with the model that BsSMC affects chromosome compaction by constraining positive supercoils. Interestingly, SMC-containing complexes in eukaryotes are able to constrain positive supercoils in vitro and affect chromosome architecture suggesting that there is a conserved function for SMC proteins in chromosome structure. I also determined the subcellular localization of BsSMC. I found that BsSMC is a moderately abundant protein that can bind to many regions of the chromosome. A portion of BsSMC localizes in a pattern similar to the replication machinery.(cont.) Simultaneous localization of BsSMC and a component of the replisome revealed that they are usually in the same region of the cell but are not always colocalized. Finally, the formation of BsSMC foci is dependent on the presence of the nucleoid but not ongoing replication. I propose that BsSMC is acting to compact newly replicated DNA by affecting DNA topology and is thereby facilitating the partitioning of sister chromosomes to opposite halves of the cell.by Janet C. Lindow.Ph.D

Structural Maintenance of Chromosomes Protein of Bacillus subtilis Affects Supercoiling In Vivo

Structural maintenance of chromosomes (SMC) proteins are found in nearly all organisms. Members of this protein family are involved in chromosome condensation and sister chromatid cohesion. Bacillus subtilis SMC protein (BsSMC) plays a role in chromosome organization and partitioning. To better understand the function of BsSMC, we studied the effects of an smc null mutation on DNA supercoiling in vivo. We found that an smc null mutant was hypersensitive to the DNA gyrase inhibitors coumermycin A1 and norfloxacin. Furthermore, depleting cells of topoisomerase I substantially suppressed the partitioning defect of an smc null mutant. Plasmid DNA isolated from an smc null mutant was more negatively supercoiled than that from wild-type cells. In vivo cross-linking experiments indicated that BsSMC was bound to the plasmid. Our results indicate that BsSMC affects supercoiling in vivo, most likely by constraining positive supercoils, an activity which contributes to chromosome compaction and organization

Feasibility and Acceptability of the Youth Aware of Mental Health (YAM) Intervention in US Adolescents

Suicide is the second leading cause of death among US adolescents, and rates of suicide among youth have been increasing for the past decade. This study assessed the feasibility and acceptability of the universal, school-based Youth Aware of Mental Health (YAM) program, a promising mental health promotion and suicide primary prevention intervention, in US youth. Using an uncontrolled design, the feasibility and acceptability of delivering and studying YAM were assessed in Montana and Texas schools. Thirteen of 16 (81.3%) schools agreed to support YAM delivery, and five Montana and 6 Texas schools were included in analyses. Facilitators delivered YAM in 78 classes (1,878 students) as regular high school curriculum. Of the total number of students who received YAM, 519 (27.6%) provided parental consent and assent. 436 (84.0%) consented students participated in pre- and post-surveys. Students, parents, and school staff found YAM highly acceptable based on satisfaction surveys. In summary, this study found YAM feasible to implement in US schools. Results also suggest students, parents, and school staff supported school-based programs and were highly satisfied with the YAM program. A randomized controlled trial is warranted to test the efficacy of YAM in promoting mental health and preventing suicidal thoughts and behaviors in US adolescents.This work was supported in part by Montana state legislative funding (Montana Research & Economic Development Initiative [Byerly MJ PI]), Montana State University research funds, Montana INBRE [NIGMS P20GM103474], the Rees-Jones Foundation (Trivedi MH PI), and the UT Southwestern Center for Depression Research and Clinical Care.12 month embargo; published online: 04 July 2019This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Use of a Fully Automated Internet-Based Cognitive Behavior Therapy Intervention in a Community Population of Adults With Depression Symptoms: Randomized Controlled Trial

Background: Although internet-based cognitive behavior therapy (iCBT) interventions can reduce depression symptoms, large differences in their effectiveness exist. Objective: The aim of this study was to evaluate the effectiveness of an iCBT intervention called Thrive, which was designed to enhance engagement when delivered as a fully automated, stand-alone intervention to a rural community population of adults with depression symptoms. Methods: Using no diagnostic or treatment exclusions, 343 adults with depression symptoms were recruited from communities using an open-access website and randomized 1:1 to the Thrive intervention group or the control group. Using self-reports, participants were evaluated at baseline and 4 and 8 weeks for the primary outcome of depression symptom severity and secondary outcome measures of anxiety symptoms, work and social adjustment, psychological resilience, and suicidal ideation. Results: Over the 8-week follow-up period, the intervention group (n=181) had significantly lower depression symptom severity than the control group (n=162; P<.001), with a moderate treatment effect size (d=0.63). Moderate to near-moderate effect sizes favoring the intervention group were observed for anxiety symptoms (P<.001; d=0.47), work/social functioning (P<.001; d=0.39), and resilience (P<.001; d=0.55). Although not significant, the intervention group was 45% less likely than the control group to experience increased suicidal ideation (odds ratio 0.55). Conclusions: These findings suggest that the Thrive intervention was effective in reducing depression and anxiety symptom severity and improving functioning and resilience among a mostly rural community population of US adults. The effect sizes associated with Thrive were generally larger than those of other iCBT interventions delivered as a fully automated, stand-alone intervention.National Institute of General Medical Sciences of the National Institutes of Health, United States Department of Health & Human Services, National Institutes of Health (NIH) - USA NIH National Institute of General Medical Sciences (NIGMS) [P20GM103474, U54GM115371, 5P20GM104417]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

CD4⁺ T cells from protected Subject A produce proinflammatory cytokines following infection with live <i>C. jejuni</i>.

<p>PBMCs from pre-challenge (D0) and post-infection timeponts were stimulated with <i>C. jejuni</i> antigen in an <i>ex vivo</i> assay and assessed for CD4⁺ cytokine production by flow cytometry. Responses depicted represent the percentage of CD4⁺ T cells producing cytokine from CAg-stimulated PBMCs (CAg stimulation minus negative control). (*150 =  Day of homologous re-challenge.)</p

Proinflammatory cytokines and a chemokine are produced with specific kinetics post-primary infection with <i>C. jejuni</i>.

<p>We analyzed CD4⁺ T cells for the production of IFNγ⁺, TNFα⁺, IL-2⁺, and MIP-1β⁺ for eight subjects challenged with <i>C. jejuni</i> at multiple timepoints pre- and post-primary infection. Responses shown are the percentage of cytokine positive CD4⁺ T cells from CAg-stimulated PBMCs with the background percentage of cytokine-positive T cells in the negative control (PBS) subtracted. CD4⁺ T cells producing each cytokine were reported for 3 time-points post-challenge: D7 (blue), D14 (red), and D28 (black). A) CD4⁺IFNγ⁺ T cells; B) CD4⁺TNFα⁺ T cells; C) CD4⁺IL-2⁺ T cells; and D) CD4⁺MIP-1β⁺ T cells. An asterisk denotes a significant difference between a response on a post-challenge day and D0 (yellow): * P<.05 and ** P<.01. Statistics were determined using repeated measures analysis of variance were not available for Subject B after re-infection.</p

Peripheral CD4⁺ T Cell Cytokine Responses Following Human Challenge and Re-Challenge with <i>Campylobacter jejuni</i>

<div><p><i>Campylobacter jejuni</i> is a leading cause of human gastroenteritis worldwide; however, our understanding of the human immune response to <i>C. jejuni</i> infection is limited. A previous human challenge model has shown that <i>C. jejuni</i> elicits IFNγ production by peripheral blood mononuclear cells, a response associated with protection from clinical disease following re-infection. In this study, we investigate T lymphocyte profiles associated with campylobacteriosis using specimens from a new human challenge model in which <i>C. jejuni</i>-naïve subjects were challenged and re-challenged with <i>C. jejuni</i> CG8421. Multiparameter flow cytometry was used to investigate T lymphocytes as a source of cytokines, including IFNγ, and to identify cytokine patterns associated with either campylobacteriosis or protection from disease. Unexpectedly, all but one subject evaluated re-experienced campylobacteriosis after re-challenge. We show that CD4⁺ T cells make IFNγ and other pro-inflammatory cytokines in response to infection; however, multifunctional cytokine response patterns were not found. Cytokine production from peripheral CD4⁺ T cells was not enhanced following re-challenge, which may suggest deletion or tolerance. Evaluation of alternative paradigms or models is needed to better understand the immune components of protection from campylobacteriosis.</p></div

Monofunctional CD4⁺ T cells from naïve and veterans post <i>C. jejuni</i> exposure are dominant over multifunctional cells.

<p>The kinetics of T cell responses are shown, separating CD4⁺ phenotypes based on the combinations of cytokines they produced (designated by +/-) under the x-axis. X-axis shows the combinations of IFNγ, TNFα, IL-2, and MIP-1β producing cells. Each colored bar designates the interquartile range (IQR). Days evaluated include: D0, D7, D14, D28, D98, D105, D112, and D126. A) Monofunctional CD4⁺ phenotypes. B and C) Multifunctional CD4⁺ phenotypes relative to D0. Statistically significant days are relative to D0 (Wilcoxon ranked test) and P≤0.05 is designated by “<b>*</b>”.</p

CD4⁺ T cell responses did not show a specific signature following re-challenge with the homologous <i>C. jejuni</i> strain.

<p>The effect of challenge on <i>C. jejuni</i> veterans shows a diverse T cell profile compared to naïve subjects. Eight subjects were re-dosed with the homologous <i>C. jejuni</i> CG8421 strain three months after initial infection. We examined CD4⁺ T cell responses for the production of IFNγ⁺, TNFα⁺, IL-2⁺, and MIP-1β at multiple timepoints pre- and post-re-infection. Responses shown are the percentage of cytokine positive CD4⁺ T cells from CAg-stimulated PBMCs with the background percentage of cytokine-positive T cells in the negative control (PBS) subtracted. D98 represents PBMCs from a blood drawn prior to re-infection. Bars represent percent of CD4⁺ T cells detected on specific days: D98 (day of re-dosing, yellow); D105 (blue); D112 (red); and D126 (black). No significant changes were observed post re-challenge compared to D98.</p