The enteropathogenic bacterium Yersinia pseudotuberculosis binds to β1 integrins on a host cell via its surface protein invasin. This event stimulates signal transduction to the actin cytoskeleton of the eukaryotic cell, which allows the cell to engulf the bacterium that is attached to its surface. However, the pathogen Y. pseudotuberculosis can evade such phagocytosis by injecting virulence effectors that interfere with the antipathogenic machinery of the host cells. One of these virulence effectors is the tyrosine phosphatase YopH. Through its enzymatic activity, YopH blocks phagocytosis by affecting the signalling that is associated with cytoskeletal rearrangements. Cas is a substrate of YopH in both professional and non-professional phagocytes. We showed that YopH binds to the central substrate domain of Cas and that this interaction is required for YopH to target focal adhesion structures in host cells. We also demonstrated that YopH binds another substrate, FAK, through Cas. Moreover, we suggested that targeting of Cas is necessary for the cytotoxic effects mediated by YopH. The protein Fyb is specific to immune cells, and it has been identified as a substrate of YopH in macrophages. We discovered that both the N-terminal substrate-binding domain and the C-terminal catalytic region of YopH bind Fyb in a phosphotyrosine-dependent manner. Moreover, we observed that both the substrate-binding domain and the phosphatase activity of YopH are essential for the effects of this protein on macrophages, which include dephosphorylation of Fyb, blocking of phagocytosis, and cytotoxicity. The role of Fyb in macrophages is largely unknown, although there is evidence that this protein is involved in integrin-linked actin organization. We identified a novel interaction partner of Fyb, mAbp1, which is a protein that binds to F-actin. Studies in vitro indicated that mAbp1 binds to the N terminus of Fyb via a C-terminal SH3 domain. We also found that both Fyb and mAbp1 co-localize with F-actin at the leading edges of macrophages. Further studies suggested that mAbp1 influences the spreading of macrophages and the antiphagocytosis mediated by pathogenic Yersinia. These results support a role for Fyb in signalling that affects F-actin dynamics, and they also provide additional insight into the mechanisms involved. Fyb has been shown to form a complex with SKAP-HOM, another substrate of YopH in macrophages. Our data implied that the level of SKAP-HOM protein depends on the presence of Fyb, but the function of the Fyb/SKAP-HOM complex in macrophages has not been determined. However, since Fyb is the only known haematopoietic-specific substrate of YopH, it is possible that Fyb is involved in other antimicrobial functions.

published_or_final_version / Architecture / Master / Master of Architecture

published_or_final_version / Architecture / Master / Master of Architecture

Made available in DSpace on 2014-12-17T15:30:54Z (GMT). No. of bitstreams: 1 PedroHASL_Dissret.pdf: 4618668 bytes, checksum: 5bca73a0220258bdbd17a75573adb995 (MD5) Previous issue date: 2009-08-31 / Oral and facial bone defects can undertake appearance, psychosocial well-being and stomathognatic function of its patients. Over the yerars several strategies for bone defect regeneration have arised to treat these pathologies, among them the use of frozen and irradiated bone allograft. Manipulation of bone grafts it s not determined yet, and several osteotomy alternatives can be observed. The present work evaluated with a microscope the bone fragments obtained from different osteotomy methods and irrigation on rings and blocks allografts irradiated and frozen at 80? negative in a rabbit model. The study is experimental in vitro and it sample was an adult male New Zealand rabbit. The animal was sacrificed to obtain long bones, that were submitted to freezing at 80? negative and irradiated with Cobalt- 60. Then the long bones were sectioned into 24 bone pieces, divided into 4 groups: G1 (n=06) osteotomy was performed with bur No. 6 forming rings with 5 mm thickness with high-speed handpiece with manual irrigation; G2 (n=06) osteotomy was performed with bur No. 6 forming rings with 5 mm thick with surgical motor with a manual irrigation rotation 1500 rpm; GA (n=06), osteotomy with trephine using manual irrigation with saline; and GB (n=06), osteotomy with trephine using saline from peristaltic pumps of surgical motor. Five bone pieces of each group were prepared for analysis on light microscopy (LM) and one on electronic scan electronic microscopy (SEM). On the SEM analysis edges surface, presence of microcracks and Smear Layer were evaluated. Analyzing osteotomy technics on SEM was observed: increased presence of microcracks cutting with high speed; increased presence of areas covered by Smear Layer when cutting with motor implant. The irrigation analysis with SEM was observed: that the presence of microcracks does not depend on the type of irrigation; on manual irrigation, there was greater discrepancy between the cutting lines. The descriptive analysis of the osteotomy and irrigation process on LM showed: histological analysis showing the bony margins with clear tissue changed layer, composed of blackened tissue of charred appearance near to the cortical bone; on the edges of the bony part, bone fragments that were displaced during the bone cut and bone irregularities were observed. After analysis of results we can conclude: that there was greater regularity of the bone cut using high-speed handpiece than using motor implant; the cut with trephine using saline irrigated from peristaltic pumps of surgical motor showed greater homogeneity when compared with manual irrigation; charred tissue was found in all obtained bone samples, whit no significant statistically difference on the proportion of carbonization of the two analysed technics / Os defeitos ?sseos bucais e faciais comprometem a apar?ncia, o bem estar psicossocial e a fun??o estomatogn?tica dos seus portadores. Diante da necessidade de tratamento dessas patologias, surgiram, com o decorrer do tempo, diversas estrat?gias para a regenera??o de defeitos ?sseos, dentre elas o uso de aloenxerto ?sseo congelado e irradiado. A manipula??o dos enxertos ?sseos ainda n?o est? determinada, podendo-se observar v?rias alternativas de osteotomia. Este trabalho avaliou microscopicamente os fragmentos ?sseos obtidos por diferentes m?todos de osteotomia e de irriga??o sobre an?is e blocos de aloenxertos irradiados e congelados a 80?C negativos de coelho. O estudo ? do tipo Experimental in vitro e teve como amostra 01 coelho, adulto, da ra?a New Zealand. O animal foi sacrificado para obten??o de ossos longos, os quais foram congelados a 80? negativos e irradiados com Cobalto-60. Em seguida, os ossos foram seccionados em 24 pe?as ?sseas, divididos em quatros grupos: G1 (n=06) foi realizado a osteotomia com broca esf?rica n? 6 formando an?is com 5 mm de espessura com caneta de alta rota??o com irriga??o manual; G2 (n=06) foi realizado a osteotomia com broca esf?rica n? 6 formando an?is com 5 mm de espessura com motor cir?rgico com irriga??o manual a uma rota??o de 1500 rpm; GA (n=06), osteotomia com trefina usando irriga??o manual com soro fisiol?gico; e GB (n=06), osteotomia com trefina usando soro fisiol?gico proveniente de bombas perist?lticas do motor cir?rgico. De cada grupo, cinco pe?as ?sseas foram destinadas ? an?lise em Microscopia de Luz (ML) e uma analisada por Microscopia Eletr?nica de Varredura (MEV). A an?lise por ML levou em considera??o a presen?a de tecido carbonizado. Na an?lise por MEV levou em considera??o: superf?cie das bordas; presen?a de microfissuras e Smear Layer. Ao analisar a t?cnica de osteotomia utilizando MEV observa-se: maior presen?a de microfissuras ao corte com alta rota??o; maior presen?a de ?reas cobertas por uma camada de smear layer em cortes com motor de implante. Na analise da irriga??o com MEV observou-se que: a presen?a de microfissuras n?o depende do tipo de irriga??o; na irriga??o manual, verificou-se uma discrep?ncia maior entre as linhas de corte. Ao avaliar descritivamente o processo de osteotomia e irriga??o na ML, verificou-se que: na an?lise histol?gica as margens ?sseas apresentavam uma evidente camada alterada de tecido, composta por um tecido enegrecido de aspecto carbonizado, pr?ximo ao osso cortical; nas margens da pe?a ?ssea foram observados fragmentos ?sseos deslocados durante o corte ?sseo e irregularidades ?sseas. Ap?s an?lise dos resultados, pode-se concluir que: houve maior regularidade do corte ?sseo utilizando caneta de alta rota??o do que motor de implante; o corte com trefina usando irriga??o com bombas perist?lticas do motor de implante se mostrou mais homog?nea quando comparada ? t?cnica com irriga??o manual; tecido carbonizado foi encontrado em todos os esp?cimes ?sseos obtidos, sem diferen?a estatisticamente significativa na propor??o de carboniza??o nas duas t?cnicas de irriga??o estudadas

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-02-17T19:43:31Z No. of bitstreams: 1 DanielChavesDeLima_TESE.pdf: 22514409 bytes, checksum: 31f3c8faf388b52b979837aa634b9a04 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-02-20T18:50:56Z (GMT) No. of bitstreams: 1 DanielChavesDeLima_TESE.pdf: 22514409 bytes, checksum: 31f3c8faf388b52b979837aa634b9a04 (MD5) / Made available in DSpace on 2017-02-20T18:50:56Z (GMT). No. of bitstreams: 1 DanielChavesDeLima_TESE.pdf: 22514409 bytes, checksum: 31f3c8faf388b52b979837aa634b9a04 (MD5) Previous issue date: 2016-09-23 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Chromobacterium violaceum is a ?-proteobacteria commonly found around tropical and subtropical regions throughout the globe. It produces many metabolites with biotechnological properties such as antitumoral peptides, antibiotics and polymers that have potential to replace the oil-based ones. Although it has been extensively studied over the past 40 years, there are many aspects of C. violaceum that remains unclear until today. We have conducted a biochemical study on the homologous recombination (HR) machinery of C. violaceum, mainly in RecA and its paralog, RadA/Sms. We performed in vitro assays from initial and late steps of HR such as D-loop formation and branch migration, respectively, with their corresponding molecular actors and how RadA/Sms influenced each one. We observed cvRadA/Sms influences negatively D-loop formation promoted by cvRecA and through pull-down assay we have observed an interaction between these two proteins. We also observed the DNA-binding preference of cvRadA/Sms and cvRecA and observed that this protein binds preferentially to dsDNA instead ssDNA, unlike cvRecA. No involvement of cvRadA/Sms on branch migration reactions was detected. In this work, we also described, for the first time, the isolation, sequencing and annotation of a new plasmid from C. violaceum, which we named ChVi1 and has 44,236 base pairs, 39 predicted open reading frames (ORFs) and, possibly, two origins of replication. Most of the ORFs codes for hypothetical and structural bacteriophage proteins. By using restriction digestion and Next-generation sequencing (NGS) we also looked for the presence of a similar plasmid in other seven C. violaceum strains isolated from amazon region. Our analysis suggest the presence of a plasmid similar to ChVi1 in two of these strains. The present work describes for the first time a biochemical characterization of RadA/Sms and RecA from C. violaceum which have different roles in HR. Moreover, the discovery of ChVi1 opens a path to further explore C. violaceum?s biology.

Quasi-hom-Lie algebras (qhl-algebras) were introduced by Larsson and Silvestrov (2004) as a generalisation of hom-Lie algebras, which are a deformation of Lie algebras. Lie algebras are defined by an operation called bracket, [·,·], and a three-term Jacobi identity. By the theorem from Hartwig, Larsson, and Silvestrov (2003), this bracket and the three-term Jacobi identity are deformed into a new bracket operation, <·,·>, and a six-term Jacobi identity, making it a quasi-hom-Lie algebra. Throughout this thesis we deform the Lie algebra sl2(F), where F is a field of characteristic 0. We examine the quasi-deformed relations and six-term Jacobi identities of the following polynomial algebras: F[t], F[t]/(t2), F[t]/(t3), F[t]/(t4), F[t]/(t5), F[t]/(tn), where n is a positive integer ≥2, and F[t]/((t-t0)3). Larsson and Silvestrov (2005) and Larsson, Sigurdsson, and Silvestrov (2008) have already examined some of these cases, which we repeat for the reader's convenience. We further investigate the following σ-twisted derivations, and how they act in the different cases of mentioned polynomial algebras: the ordinary differential operator, the shifted difference operator, the Jackson q-derivation operator, the continuous q-difference operator, the Eulerian operator, the divided difference operator, and the nilpotent imaginary derivative operator. We also introduce a new, general, σ-twisted derivation operator, which is σ(t) as a polynomial of degree k.

published_or_final_version / Urban Planning / Master / Master of Science in Urban Planning

In the 1970’s, L. Lovász proved that two graphs G and H are isomorphic if and only if for every graph X , the number of homomorphisms from X → G equals the number of homomorphisms from X → H . He used this result to deduce cancellation properties of the direct product of graphs. We develop a result analogous to Lovász’s theorem, but in the class of graphs without loops and with weak homomorphisms. We apply it prove a general cancellation property for the strong product of graphs.

In this dissertation it is indicated that gender is a social construct, while sex is biologically determined. The concept of gender refers to that which is understood within a certain society to define masculinity and femininity, the power struggle between the two sexes, as well as the social limitations which are placed on people's behaviour as a result of gender. Children's and young adult's literature exert a great influence on the youth's idea of gender roles. The social and cultural history of South African society is used in this study to explore stereotypical gender roles in Afrikaans youth literature. The role of a patriarchal society, homosexuality, and changing perceptions of gender roles are investigated. It is indicated that in both English and Afrikaans children's and young adult's literature the portrayal of gender roles is often unrealistic, stereotypical, and contains sexist language. Two novels namely, Gooi horn in die slool (1971) and Skilpoppe (1998), are analysed using the following categories: male or female author, representation of gender roles, and use of sexist language. The teaching implications of the findings for the second language learner are then articulated. OPSOMMING In hierdie skripsie is aangetoon dat geslaglelikheid ("gender"), anders as geslag wat biologies bepaal is, 'n sosiale konstruk is. Geslagtelikheid hou verband met wat in 'n bepaalde samelewing onder manlikheid en vroulikheid verstaan word, asook met magsverhoudings tussen die twee geslagte en sosiale beperkings wat op grond van geslagtelikheid op mense se gedrag geplaas word. Jeugliteratuur oefen 'n groot invloed uit op jeugdiges se siening van geslagtelikheid. Die sosiale en kultuur-historiese agtergrond in die Suid-Afrikaanse samelewing word in die studie gebruik om die uitbeelding van geslagtelikheid in die Afrikaanse jeugliteratuur te problematiseer. Die rol van 'n patriargale samelewing, homoseksualiteit en veranderde sienings oor geslagtelikheidsrolle word onder andere uitgelig. Daar word aangetoon dat die uitbeelding van geslagtelikheid in sowel Engelse as Afrikaanse jeugliteratuur dikwels baie onrealisties is en wemel van stereotiperings en seksistiese taalgebruik. Twee jeugverhale, naamlik Gooi ham in die slool (1971) en Skilpoppe (1998), word aan die hand van 'n aantal kategoriee, naamlik outeur, uitbeelding van geslagtelikheid en seksistiese taalgebruik geanaliseer, voordat onderrigimplikasies vir die tweedetaalklaskamer aangedui word. / Thesis (M.A.) - University of Natal, Durban, 2001.

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