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Incorporation of bio-inspired microparticles within embryonnic stem cell aggregates for directed differentiationSullivan, Denise D. 27 May 2016 (has links)
Embryonic stem cells (ESCs) are a unique cell population that can differentiate into all three embryonic germ layers (endoderm, mesoderm, and ectoderm), rendering them an invaluable cell source for studying the molecular mechanisms of embryogenesis. Signaling molecules that direct tissue patterning during embryonic development are secreted by ESC aggregates, known as embryoid bodies (EBs). As many of these signaling proteins interact with the extracellular matrix (ECM), manipulation of the ESC extracellular environment provides a means to direct differentiation. ECM components, such as glycosaminoglycans (GAGs), play crucial roles in cell signaling and regulation of morphogen gradients during early development through binding and concentration of secreted growth factors. Thus, engineered biomaterials fabricated from highly sulfated GAGs, such as heparin, provide matrices for manipulation and efficient capture of ESC morphogens via reversible electrostatic and affinity interactions. Ultimately, biomaterials designed to efficiently capture and retain morphogenic factors offer an attractive platform to enhance the differentiation of ESCs toward defined cell types. The overall objective of this work was to examine the ability of microparticles synthesized from both synthetic and naturally-derived materials to enhance the local presentation of morphogens to direct ESC differentiation. The overall hypothesis was that microparticles that mimic the ECM can modulate ESC differentiation through sequestration of endogenous morphogens present within the EB microenvironment.
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Young people negotiating embodied subjectivities through (dis)engagement in physical educationHill, Joanne L. January 2013 (has links)
The purpose of this study was to engage with a group of students from a diverse school environment about how they construct value or status in their own and others bodies in physical education (PE) and sport. This study was premised on the notion that young people s constructions of bodies that have value affect both their sense of self and their (dis)engagement with physical activity in and out of school. Sport, physical activity and education are not value-free in their purpose or practices, and constitute arenas in which young people learn about what those values are and how they apply to their own bodies. Learning more about how young people make embodied decisions to engage in physical activity can aid in understanding how best to create inclusive, positive experiences within PE and youth sport. The feminist / poststructuralist theoretical framework that this research draws upon focuses attention on the constructions of embodied subjectivities through an individual s subject positions amongst multiple discourses. These discourses are (re)produced but shift as individuals take up and negotiate positions through the multiple narratives available to them. By linking these notions to that of physical capital, this study explores how individuals practices affect how they might be seen as valued. This study pays particular attention to gendered and racialised constructions of bodies in PE and sport, as literature identifies concerns about equity in participation and representation. Data were generated over one school year with a cohort of students in Year 9 of an ethnically diverse secondary school in the East Midlands, UK. Fourteen boys and eleven girls volunteered to take part in a collaborative visual ethnographic project consisting of a fortnight s photo diary and the sharing of participant-produced images in group interviews. Taped group interviews, participants photographs, field notes from observations of the participants PE lessons and researcher s photographs of the school notice boards were collated and analysed using a combination of thematic, discourse and content analyses. Findings indicated that the participants constructed as valued bodies those that are good at PE : meaning competency, strength and a desire and ability to win. Alongside this, students also valued fit, not fat bodies, and the display of effort or trying one s best. These constructions were often tied to their potential to perform convincingly. The students took up positions in relation to these notions of status, sometimes investing in practices that would develop their bodies in these ways. Participants fluid subjectivities as they negotiated different activities, physical cultures, and assumptions about gendered and racialised bodies affected their choices not just whether to engage but in what ways they would engage in physical activity.
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The use of democratic institutions as a strategy to legitimize authoritarian rule.Michalik, Susanne 05 1900 (has links)
Numerous authoritarian states use institutions usually associated with democratic regimes like a constitution, elections, and a legislature. This seems to be counterintuitive. Authoritarian regimes should rather shrink away from democratic institutions. Elections can be won by the opposition and legislatures can make decisions against the interests of the ruler. So, why do autocratic regimes install institutions which limit their power and threaten their survival in office? Assuming actors behave rationally, one should expect authoritarian rulers only to introduce procedures working in their favor. This study looks at the effect of institutions in authoritarian regimes. The findings suggest that legislatures significantly lower the chances of regime breakdown in the long run. However, particularly in election years, authoritarian regimes are facing a higher likelihood of failure.
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Analyzing the Biological Role of Human DREF and its Interaction with the Adenovirus E1A ProteinRadko, Sandi 11 September 2015 (has links)
Early region 1A (E1A) protein is the first protein expressed following viral infection. E1A proteins initiate the cell cycle in infected cell by altering cellular gene expression and also activate expression of other viral genes enabling viral replication. The C-terminus of E1A is the least-characterized region of the protein, with few known binding partners, however DREF has been identified as a novel binding partner. My studies have determined that DREF directly binds to E1A and has a role in the virus life cycle. DREF is a restriction factor for virus growth and is a component of viral replication centres. DREF is SUMOylated and SUMOylation appears to affect localization to viral replication centres. DREF co-localizes with PML bodies and subcellular distribution of DREF is altered by the presence of E1A. This work provides a platform to study the role of DREF in uninfected cells, and in HAdV biology and its possible role in antiviral response. / October 2015
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Meckelin Functions in the Guided Movement and Orientation of Basal Bodies Prior to Duplication in Paramecium tetraureliaPicariello, Tyler August 01 January 2015 (has links)
Ciliopathies are a group of disorders that arise from ciliary dysfunction. Meckelin (MKS3 or TMEM67) is a conserved transmembrane protein found at the transition zone of ciliated cells. In humans MKS3 is one of 3 genes linked to the ciliopathy Meckel Syndrome. This disease is characterized by occipital meningioencephalocoele, polycystic kidneys, fibrotic changes to the liver, postnatal polydactyly and situs inversus.
Paramecium tetraurelia is a single celled ciliated eukaryote. Its surface is organized of a meshwork of cortical units that run the length of the cell. At the center of the cortical units are either one or two basal bodies. In two basal body units only the posterior basal body is ciliated. From the ciliated basal body, three rootlets project in stereotypical orientations: the post-ciliary rootlet projects posteriorly, the transverse microtubule projects toward the adjacent basal body row and the striated rootlet projects anteriorly. Both the post-ciliary rootlet and transverse microtubule are microtubule-based structures. The striated rootlet is composed of multiple subunits that are predicted to have conserved segmented coiled coil domains known as SF-Assemblin domains.
In Picariello at al., 2014, we showed that MKS3 is present in the transition zone of Paramecium tetraurelia and that RNAi for MKS3 leads to global ciliary loss. Additionally, RNAi for MKS3 results in the disorganization of the basal body rows. Within the areas of disorganization, the basal bodies along with their striated rootlets, post-ciliary rootlets and transverse microtubules are rotated away from their expected orientation. Interestingly, the post-ciliary rootlet and transverse microtubule are still attached at the expected angles relative to each other within the areas of disorganization. Initial GST pull-down experiments using the coiled coil domain of MKS3 suggest a potential interaction between MKS3 and the striated rootlet family members KdC1 and KdB2.
To test potential interactions between MKS3 and the striated rootlet we identified 27 potential striated rootlet family members in Paramecium. Full-length sequences for 13 of these genes were marked at their N-terminus with a 3x FLAG sequence. Components with a conserved SF-Assemblin domain were distributed uniformly within the striated rootlet. Components lacking the SF-Assemblin domain were found in various cellular locations, but not within the striated rootlet. GST pull-down experiments utilizing the MKS3 C-terminus as bait were performed using cells expressing the FLAG-tagged striated rootlet family members. Unfortunately a clear interaction between MKS3 and the striated rootlet remains elusive.
The organized nature of the surface of Paramecium has allowed us to identify a previously unrealized function for MKS3. Our immunofluorescence data suggest that MKS3 functions outside the transition zone to maintain basal body row organization by potentially contributing to a link between the basal body and the striated rootlet. Without the link, the migrating basal bodies are free to rotate and project their rootlets in the wrong directions. Although the nature of the link remains elusive, the identification of disorganized basal body rows upon MKS3 reduction suggests that, in addition to ciliary dysfunction, basal body polarity defects may contribute to the development of MKS.
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Transport U2 snRNA do Cajalových tělísek / U2 snRNA targeting to Cajal bodiesRoithová, Adriana January 2014 (has links)
In the cell we can find a lot of small noncoding RNAs, which are important for many processes. Among those RNAs are small nuclear RNA uridin rich, which with proteins create U snRNP.These particles play important role in pre-mRNA splicing. In this process are noncoding sequences (introns) removed and coding sequences (exons) are joined. It is catalyzed by spliceosome. The core of this spliceosome is created by U1, U2, U4, U5 and U6 snRNP. They are essential for this process. Some steps of U snRNP biogenesis proceed in nuclear structures called Cajal bodies (CB). In my thesis I focused on factors, which are important for targeting U snRNA into CB. I used U2 snRNA like a model. With the aid of microinjection of fluorescently labeled U2 snRNA mutants I found, that the Sm binding site on U2 snRNA is essential for targeting to CB. Knock down of Sm B/B'showed us, that Sm proteins are necessary for transport U2 snRNA to CB. Sm proteins are formed on U2 snRNA by SMN complex. Deletion of SMN binding site on U2 snRNA had the same inhibition effect. From these results we can see, that Sm proteins and SMN complex are important for U2 snRNA biogenesis espacially for targeting into CB. Key words: U snRNP, Cajal body, U snRNA, cell nucleus
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Localization of Ime4 in Saccharomyces cerevisiaeGhimire, Jenisha 01 May 2012 (has links)
One lesser-known but universal post transcriptional modification carried out in yeast and higher eukaryotes is the methylation of mRNA, as mediated by the Ime4 protein and its orthologs. Ime4 protein is essential for sporulation in yeast cells and for viability of higher eukaryotic cells. The precise locations of the Ime4 protein and the functions of the methylated mRNA are still largely unknown. Whereas Ime4 protein is believed to be exclusively nuclear in higher eukaryotes, we have observed the yeast Ime4 protein in the nucleus, in the cytosol and within cytosolic particles. These observations suggest that Ime4 could be a shuttling RNA binding protein, playing roles in the cytosol as well as the nucleus. As a first step to examining this idea, we tested the hypothesis that the punctuate cytosolic particles formed by Ime4 are P bodies. P bodies are transient aggregates of proteins and RNAs that form as a result of stresses such as glucose deprivation. This experiment was carried out using fluorescence microscopy using Ime4 tagged with GFP (green fluorescent protein) and the known P -body proteins Edc3, tagged with mCherry. We expected that if the proteins thus produced localized in the same place in the yeast cell, we could then deduce that Ime4 is present in P-bodies. We observed that Ime4 and Edc3 did not colocalize in the majority of cells, and thus concluded that the Ime4 granules are not P-bodies. However, our experiments showed instances of Ime4 signals near or around the P-bodies in some cells. Hence, the Ime4-containing aggregates are not likely to be P-bodies but could rather represent a different type of granule.
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Implementation of SGB fuctions (School finances and budgeting): AS case study in Bolobedu DistrictMokoena, Masilo 25 October 2006 (has links)
Student No :9712664T
MEd School of Education
Faculty of Humanities / After the establishment of the first democratic government in South Africa, the Education Ministry
committed itself to transforming the education system through developing new policies and legislation
aimed at achieving equitable access to education and improving the quality of education. One of the school
reform policies is the South African Schools Act (SASA), which is aimed at democratising and improving
school education. It does so by devolving responsibilities and powers on schools, thereby promoting more
democratic governance of schools by school governing bodies (SGBs), which are comprised of parents,
educators, non-teaching staff and learners.
The main thrust of this study was to investigate the factors that explain how different rural schools in
Bolobedu district (Limpopo Province) interpret and implement the newly-granted SGB powers and
responsibilities regarding school finances and budgeting.
Four schools, two primary, one junior secondary and one senior secondary, were sampled. At some of them
SGBs appeared to be doing well, while at others the SGBs appeared to be overwhelmed by the new task of
managing school finances and budgeting. The research instruments used in carrying out this study were
interview schedules, documentary data analysis and non-participant observation of SGB meetings.
Interviews were conducted with educators, principals, parents and learners (members of SGBs and nonmembers).
Triangulation of data is essential for the validity and reliability of a study. This study is regarded
as valid and reliable, as there was strong correlation among the responses to most of the questions posed.
The interviewees participated willingly in the study and showed complete understanding of the questions.
The major deduction from this study is that not all SGBs in disadvantaged rural areas are unable to execute
their duties and responsibilities regarding school finances and budgeting, despite being dominated by
illiterate parents who have not had the administrative and financial experience to oversee school affairs.
The findings indicated that some poorly resourced SGBs were able to execute their duties and
responsibilities regarding school finances and budgeting, though there were some constraints. The
following factors that assisted and undermined the capacity of schools to assume their financial powers
effectively were identified:
• School-Community relationship;
• SGB capacity;
• Internal social capital; and
• Leadership strategies.
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Unpacking the political legitimacy of parliament in an emerging democracy: the case of Malawi, 1994 to 2011Jana, Michael Patrick Eliezer 11 November 2014 (has links)
Thesis submitted in fulfilment of the requirements for the
Degree of Doctor of Philosophy in Political Science
Graduate School for Humanities and Social Sciences
University of the Witwatersrand / Political legitimacy manifests differently in different state institutions, and
comprehending its dynamics is a prerequisite to understanding power, authority,
capacity, consolidation, and sustainability of any political regime. Supported by
evidence from a case study of the Malawian parliament from 1994 to 2011, my
original contribution to knowledge is that political legitimacy of representative
institutions in emerging democracies has three minimum dimensions, namely: public
perception of the acceptability and fairness of formal procedures guiding a
representative institution; public emotional attachment to the institution; and public
perception of performance effectiveness of the institution. I label these dimensions as
juridical; symbolic; and instrumental legitimacy respectively. I therefore posit that,
deficiency in any or some of the three legitimacy dimensions has the potential to
compel those represented, who may be self-confessed democrats, to demand
institutional reforms that ironically may go against the very tenets of multi-party
democracy. The Malawi parliament case shows that legitimacy deficiency of
parliament seems to be facilitated by public dissatisfaction with their local socioeconomic
status, in the context of a dysfunctional local government, and coupled with
the public perception of parliament as a responsible institution given its status in the
perceived representation hierarchy that places it above the local government. This
situation is aggravated given the fact that Malawi parliament, rightly so, is neither
institutionally nor financially supported to directly address local development issues;
and that, erroneously, the parliament is neither institutionally nor financially
supported to effectively carry out its representation function despite representation
carrying the status of a meta-function. The lack of political will for public
consultations and lack of intra-party democracy in political parties represented in
parliament has also tremendously eroded the influence of political parties hence further undermining the legitimacy of the whole multi-party regime. Using principles
of external validity in case study research therefore, the Malawian case study provides analytical insights that can be extrapolated to understand political legitimacy of
representative institutions in other emerging democracies that have similar context to
that of Malawi.
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Morfogeneze bakteriálních kolonií / Morphogenesis of bacterial coloniesČepl, Jaroslav January 2013 (has links)
The topic of this thesis has been built on previous work of our group, especially Rieger et al. 2008 and Čepl et al. 2010. We examined and described the regularity of morphogenesis of S. marcescens, morphotype F colonies (from "the fountain", because of a shape it resembles). Typical colony consists of elevated red navel, low non-pigmented ring and again elevated red rim. Structured profile of the colony together with changes in pigmentation of structures during development without need of artificial dying, provides considerable advantage in observation of the morphogenesis. Aims of this thesis were (i) to find other factors that affect the morphogenesis, (ii) to characterize interactions of S. marcescens colonies with other bacterial strains (S. rubidaea and E .coli) and finally (iii) to study the phenomenon of induced resistance to the antibiotics described in (Heal and Parsons, 2002; Lu 2004; Bernier et al. 2011) in our model organisms. (i) Mutual interactions of colonies on the plate indicates that morphogenesis is affected by autocrine signals, which diffuse into the medium and the atmosphere and affect the development of surrounding colonies. We have detected changes of pH of the medium during the development of colonies in their vicinity. At ...
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