Dissertations / Theses on the topic 'Autotransporters'
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Orner, Sherko A. "Functional characterisation of Neisseria meningitidis autotransporters MSPA and APP." Thesis, University of Nottingham, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490049.
Full textSims, Peter Vincent. "Biogenesis of BapF : a novel acylated Bordetella autotransporter." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/41811.
Full textBokhari, Syed Habib. "Characterisation and secretion mechanism of Bordetella pertussis autotransporter proteins." Thesis, University of Glasgow, 2002. http://theses.gla.ac.uk/1507/.
Full textContreras, Morales Elis Rosella. "La planeación inadecuada del transporte público de Toluca. Caso de estudio la empresa Autotransportes Suburbanos de la ciudad de Toluca y Zona Industrial , S.A de C.V. ( ATSUZI )." Tesis de Licenciatura, Universidad Autónoma del Estado de México, 2013. http://hdl.handle.net/20.500.11799/49262.
Full textEl objetivo de la presente investigación es analizar el transporte público urbano de la Zona Metrop oli tana de Toluca, en particular la empresa “Autotransportes Suburbanos de la Ciudad de Toluca y Zona Industrial, S.A. de C.V. (ATSUZI) en un contexto de movilidad urbana. La investigación se realizó con apoyo de información estadística, analizando la problemática del transporte público urbano existente en la ciudad y con ello realizar sugerencias de reordenamiento y de mov ilidad de la población de esta zona metropolitana.
Dufailu, Osman Adamu. "Role of meningococcal Neisserial autotransporter lipoprotein (NalP) in host pathogenesis." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/41127/.
Full textGagnon, Elizabeth. "The requirement of putative autochaperone motifs for autotransporter passenger domain folding." Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43502.
Full textDarch, Owen Matthew. "A study on the function of the Pseudomonas aeruainosa autotransporter PA0328." Thesis, University of Nottingham, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.523036.
Full textNoofeli, Mojtaba. "Genetic analysis and characterisation of the BapC autotransporter of bordetella pertussis." Thesis, University of Glasgow, 2008. http://theses.gla.ac.uk/105/.
Full textAit-Tahar, Kamel. "Identification and characterisation of AutA : an autotransporter protein of Neisseria meningitidis." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394868.
Full textYoo, Christopher Charles. "Investigating the Role of Trimeric Autotransporter Adhesins in Fusobacterium nucleatum Pathogenesis." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/101683.
Full textMaster of Science in Life Sciences
Mehat, Jai. "Characterisation of CapC, a novel strain-specific autotransporter in Campylobacter species." Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/841594/.
Full textAckermann, Nikolaus. "Das Yersinia-Adhäsin YadA, ein oligomerer Autotransporter als Prototyp der Oca-Familie." Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-32890.
Full textJarmander, Johan. "Improved detection and performance of surface expression from the AIDA-I autotransporter." Licentiate thesis, KTH, Bioprocessteknik (stängd 20130101), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121561.
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Hassan, Hoda Abdel-Hadi. "Identification and characterisation of app : an immunogenic autotransporter protein of Neisseria meningitidis." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368253.
Full textRossiter, Amanda Eve. "Deciphering the autotransporter pathway of Gram-negative bacteria : from regulation to secretion." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/3046/.
Full textMandyoli, Lungelo. "Structural characterization of EtpA an adhesin from enterotoxigenic Escherichia coli (ETEC)." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/60835.
Full textDissertation (MSc)--University of Pretoria, 2016.
Biochemistry
MSc
Unrestricted
Gustavsson, Martin. "Surface expression using the AIDA autotransporter : Towards live vaccines and whole-cell biocatalysis." Licentiate thesis, KTH, Bioprocessteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48575.
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Vinnova: BIO-AMINES
SIDA Vietnam: Production of viral proteins for vaccine development
Beriotto, Irene. "Optimising the autotransporter system for secretion and display of heterologous proteins on GMMA." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7652/.
Full textLatatujeva, Oksana. "Strateginių pokyčių valdymas krovininio transporto versle." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2009~D_20140626_182827-47733.
Full textSUMMARY The relevance of the theme. The recession of the economy have caused enormous loss for freight transport businesss. Many transporters are asking such questions: what means can help to avoid the loss of the freight transport businesss, how to increase the efficiency of the business, what business reorganisation programs should be undertaken, etc. These are problematic questions, which are held by transport companies every day. It is believable, that from this current situation will leave that companies, which will be concentrated into strategic changes and their management in the organization. This process means the change of the routine, the introduction of the new work methods, the raising of new strategic aims and tasks, which can be approved or opposed. Therefore, the selected management of the strategic changes, should be especially well considered and valued. It is relevant for every organization, which seeks the competitive advantage in the market. Aim of research – find out the potential of improving strategic change management in freight transport business. Tasks of research: 1. To reveal the part of strategic changes and to explore it’s management. 2. To accomplish the analysis of freight transport business. 3. To review the methodology of strategic changes management in freight transport business. 4. To research strategic changes management in freight transport business. 5. To find out the possibilities of improving strategic changes in freight transport... [to full text]
Scaglione, Patricia. "THE STRUCTURAL AND FOLDING CHARACTERISTICS OF THE PLASMID-ENCODED TOXIN FROM ENTEROAGGREGATIVE ESCHERICHIA COLI." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3880.
Full textM.S.
Department of Biomolecular Science
Burnett College of Biomedical Sciences
Molecular and Microbiology MS
CERECEDO, ESCALANTE ABDEEL, and DE SANTIAGO JAVIER VALENCIA. "BARRERAS AL CRECIMIENTO DE UNA MICRO, PEQUEÑA Y MEDIANA EMPRESA DE AUTOTRANSPORTE FEDERAL DE CARGA: EL CASO DE TRANSPORTES VALENCIA." Tesis de Licenciatura, UNIVERSIDAD AUTÓNOMA DEL ESTADO DE MÉXICO, 2018. http://hdl.handle.net/20.500.11799/79810.
Full textGrin, Iwan [Verfasser], and Dirk [Akademischer Betreuer] Linke. "Assisted Secretion of a Trimeric Autotransporter Adhesin from Salmonella / Iwan Grin ; Betreuer: Dirk Linke." Tübingen : Universitätsbibliothek Tübingen, 2015. http://d-nb.info/1197058044/34.
Full textCoutte, Loïc. "Caractérisation et rôle biologique de la protéase SphB1 impliquée dans la maturation de la FHA de Bordetella pertussis au cours de sa sécrétion." Paris 6, 2004. http://www.theses.fr/2004PA066071.
Full textAshgar, Sami S. "Identification and characterisation of two novel autotransporter proteins, designated CapA and CapB, in Campylobacter jejuni." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408625.
Full textDoebel-Hickok, Monte. "Characterizing the secretion and function of TcfA : a unique autotransporter and virulence factor in Bordetella pertussis." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/64235.
Full textScience, Faculty of
Microbiology and Immunology, Department of
Graduate
Gustavsson, Martin. "Influence of recombinant passenger properties and process conditions on surface expression using the AIDA-I autotransporter." Doctoral thesis, KTH, Bioprocessteknik (stängd 20130101), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122230.
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Aragão, Annelize Zambon Barbosa 1984. "Vat (vacuolating autotransporter toxin) produzida por APEC (avian pathogenic Escherichia coli) = efeitos intracelulares e distribuição filogenetica." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317304.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-15T17:06:12Z (GMT). No. of bitstreams: 1 Aragao_AnnelizeZambonBarbosa1984-_M.pdf: 1442209 bytes, checksum: 20b02ae5cd0351830e8e623b5e9c17a4 (MD5) Previous issue date: 2010
Resumo: Escherichia coli isoladas de lesões de celulite aviária em frangos de corte produzem uma citotoxina que causa intensa vacuolização citoplasmática em células de origem aviária, mas não em células de mamíferos. Esta citotoxina foi denominada Vat (vacuolating autotransporter toxin) e apresenta massa molecular de 56 kDa e ponto isoelétrico de 6,37. Estudos preliminares comprovaram que a Vat induz, em frangos de corte, respostas inflamatórias liberando as citocinas TNF-a e IL-10, indicando o seu papel relevante no desenvolvimento da celulite aviária. A dose citotóxica para 50% das células foi determinada em 40 µg.mL-1. A Vat aplicada sobre cultura de células FEG (fibroblasto de embrião de galinha) induz perda da viabilidade em 50% células após 18 horas de ensaio. Ensaios com a toxina indicam que, após 24 horas, os lisossomos mostram-se bastante comprometidos (37% viáveis), a viabilidade mitocondrial decresce e se mantém durante as 24 horas do ensaio em cerca de 55%, havendo uma redução acentuada das mitocôndrias viáveis após 36 horas da aplicação da Vat. A membrana plasmática das células FEG também sofre alterações de integridade, liberando 66,7 unidades de LDH (lactato desidrogenase)/mL, após 12 horas de ensaio (pico máximo de liberação, que corresponde a 51,7% do conteúdo total de LDH em células FEG). A Vat induz alterações no citoesqueleto das células FEG e os ensaios com o marcador fluorescente Acridine Orange indicam que há um aumento de RNA no citoplasma das células. Neste trabalho o gene vat foi detectado em amostras de APEC (filogrupos A e B1), UPEC e SEPEC (ambas em filogrupos B2 e D). Todas as amostras positivas para vat foram examinadas em células, sendo que 54% (27/50) apresentaram atividade vacuolizante em células FEG. Nossos resultados indicam que a Vat é uma toxina que induz diversas ações intracelulares, podendo ser chamada de toxina multifuncional
Abstract: Escherichia coli isolated from avian cellulitis lesions in broilers produce a cytotoxin that causes intense vacuolation in avian cells, but not in mammals cells. This cytotoxin, called Vat (vacuolating autotransporter toxin), has a 56 kDa protein and has a isoeletric point of 6.37. Preliminary studies have shown the Vat induce inflammatory response in broilers, by releasing cytokines TNF-a and IL-10, what indicates it can act in the avian cellulitis development. The cytotoxic dose for 50% of the cells was fixed at 40 µg.mL-1. The tests using CEF (chicken embryo fibroblasts) cells indicate Vat leads to cell viability loss in 50% of the cells after 18 hours. The tests with the toxin indicate that after 24 hours the lysosomes are 37% viable, the mitochondrial viability decreases after 24 hours (about 55%), with a remarkable reduction of viable mitochondria after 36 hours of Vat application. The CEF cells' plasma membrane of also loses integrity, releasing 66.7 units LDH (lactato dehydrogenase)/mL, after 12 hours of test (which is 51.7% of the total LDH content in CEF cells). The CEF cells' cytoskeleton also changed when exposed to Vat. Essays involving the fluorescent dye Acridine Orange indicate a RNA increase in the cytoplasm of cells. In this work the vat gene was detected in samples of APEC (A and B1 philogroups), UPEC and SEPEC (B2 and D philogroups). All vat positive samples have been tested for vat in cells, and 54% (27/50) of them have shown vacuolizing activity in CEF cells. The results indicate Vat is a toxin which induces various intracellular actions, therefore it can be called a multifunctional toxin
Mestrado
Microbiologia
Mestre em Genética e Biologia Molecular
Ngwamidiba, Maxime. "Etude moléculaire des gènes SCA1 et SCA2 codant des protéines autotransporteurs chez les membres du genre " rickettsia"." Aix-Marseille 2, 2006. http://www.theses.fr/2006AIX20660.
Full textThe history of rickettsioses is probably as ancient as human civilisation. The first documented cases of rickettsioses dates back to 1812. In early part of the last century (1910) Ricketts and von Prowazek laid the foundation of modern rickettsiology. Their pioneering works eventually led to the recognition of new species and Rickettsiales infections. As soon as Rickettsia are the first strictly intracellular bacteria described, its taxonomy gathered on the basis of this criterion, and a great number of kinds of bacteria which will be identified only with the advent of the sequencing and the discovery of molecular clocks such as ribosomal 16S RNA and cytochrome C. Many phenotypic criterion such as morphology, tests of complement, neutralization of toxins, mousse serotyping and SDS-page proved reliable. However, gene comparison (ompA, ompB and sca4) will make it possible to very precisely determine the species containing of the genus Rickettsia and to suggest a classification supported by high bootstrap values as well as antibiotics tests. Nevertheless, the phylogenetic position of species such Rickettsia helvetica, Rickettsia canadensis and Rickettsia bellii could not be given with precision, and the polyphasic analysis of the classification of the Rickettsia species based on genes concatenation associated with phenotypic characters available might be alternatives for Rickettsia phylogeny
Shahid, Shakeel Ahmad [Verfasser]. "Structure and function of the autotransporter protein YadA : a solid-state MAS NMR study / Shakeel Ahmad Shahid." Berlin : Freie Universität Berlin, 2012. http://d-nb.info/1030383162/34.
Full textAshawesh, Mahmoud. "Investigation of the spiral secretion pattern of the serine protease autotransporter, EspC, using innovative fluorescent labelling approaches." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/38029/.
Full textSakamoto, Chizuko. "Study of the regulatory network of the surface autotransported adhesin antigen 43 in escherichia coli." Paris 7, 2013. http://www.theses.fr/2013PA077205.
Full textAg43 is an outer-membrane protein enabling E. Coli to auto-aggregate. It promotes the formation of biofilms and is implicated in the persistence of uropathogenic E. Coli strains in the urinary tract. This adhesin is regulated by a mechanism of phase variation which is very well-documented : the expression of agn43 results of the competition between the Dam methylase (activator) and the transcriptional regulator OxyR (repressor). Fiente, sister-cells can either express agn43 (phase ON) or not (phase OFF). Up-to-date, this is the only known mechanism of regulation of agn43, although the in vivo role of phase variation is still poorly understood. Although the agn43 regulatory switch leads to a heterogeneous population of ON and OFF bacteria, studies of Ag43 seldom consider potential biases associated with phase variation. We monitored agn43 ON/OFF phase-variation status genetically and phenotypically and we show that the use of populations with random agn43 ON or OFF status could result in misleading conclusions about Ag43 function or regulation. In particular, we demonstrate that Lrp and MqsR, previously identified as agn43 regulators, do not regulate agn43 expression or ON/OFF switch frequency. We also show that biofilm formation in dynamic flow conditions does not influence agn43 ON/OFF switching but physically selects aggregating agn43 ON cells. This indicates that misinterpretation is possible when studying gene expression within biofilms. Moreover, we provide evidence that ignoring the initial agn43 ON/OFF status of the E. Coli populations studied is likely to bias analyses of phenotypes associated with other E. Coli adhesins thereby emphasizing the importance of monitoring Ag43 phase-variation. On another hand, we show that the two-component system CpxAR (or Cpx), implicated in periplasmic stress response, can modulate the function of Ag43- mediated auto-aggregation. We have determined that the Cpx system is not directly regulating Ag43 expression, stability nor its translocation to the surface but rather indirectly by a `masking/unmasking' mechanism via the expression of type 1 fimbriae (fim operon), another major phase-variable adhesin of E. Coli. Moreover, we have shown that the expression offim induces the Cpx system via the lipoprotein N1pE, inducer of the Cpx system, which is involved in surface sensing, providing the first evidence of a negative feedback of type 1 fimbriae on their own expression. Furthermore, our results tend to show that OxyR is also a repressor offim expression making it a master regulator of the phase-variable adhesins of E. Coli (Ag43 and Fim). This study therefore provides a new insight into Ag43 regulation in particular regarding its interactions with other adhesins
Casasanta, Michael Anthony. "Laying the Genetic and Molecular Foundation for the Study of Fusobacterium Nucleatum in Relation to Human Health and Disease." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/88484.
Full textDoctor of Philosophy
Hernández, Casas Luis Arturo. "ANÁLISIS COMPARATIVO DE LA REGULACIÓN DEL AUTOTRANSPORTE DE MERCANCÍAS ENTRE MÉXICO Y ESTADOS UNIDOS, 1980-2016." Tesis de Licenciatura, Universidad Autónoma del Estado de México, 2018. http://hdl.handle.net/20.500.11799/95307.
Full textMedina, Estrada Juan Antonio. "“TIPIFICAR EN EL CÓDIGO PENAL FEDERAL LA PRESTACIÓN DEL SERVICIO PÚBLICO DE AUTOTRANSPORTE DE PASAJEROS SIN AUTORIZACIÓN”." Tesis de Licenciatura, Universidad Autónoma del Estado de México, 2013. http://hdl.handle.net/20.500.11799/67176.
Full textTurner, David Patrick James. "Identification and characterisation of autotransported serine protease A (AspA) in Neisseria meningitidis : a novel subtilisin-like serine protease." Thesis, University of Nottingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272370.
Full textFleetwood, Filippa. "Bacterial display systems for engineering of affinity proteins." Doctoral thesis, KTH, Proteinteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156420.
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Gawarzewski, Iris [Verfasser], and Joachim [Akademischer Betreuer] Jose. "Determination of the AIDA-I ß-barrel crystal structure: getting the clue to the autotransporter secretion pathway / Iris Gawarzewski. Gutachter: Joachim Jose." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2014. http://d-nb.info/1046404458/34.
Full textBeckett, Brian. "Structural aspects of adhesin involved in diffuse adherence (AIDA-I) and autotransporter adhesin heptosyltransferase (Aah) and their roles in «Escherichia coli» aggregation." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121300.
Full textE. coli exprimant l'adhésine impliquée dans l'adhérence diffuse (AIDA-I) causent de graves cas de diarrhée néonatale fatale. AIDA-I est une glycoprotéine, située dans la membrane externe de Gram négatif E. coli. Elle provoque l'agrégation bactérienne. L'autotransporteur adhésine heptosyltransférase (Aah) est une glycosyltransférase chez E. coli qui glycosyle AIDA-I.Dans la première partie de ce mémoire de maîtrise, nous avons observé les molécules d'AIDA sous leurs formes non agrégées et agrégées par microscopie électronique, particules isolées et tomographie électronique afin de donner un aperçu sur le mécanisme d'attachement AIDA. Notre analyse a montré que les molécules AIDA-I sous leurs formes non agrégées étaient des molécules allongées mesurant environ 320 Å en longueur et 50 Å en largeur, composées d'un seul polypeptide AIDA-I. Alors que la longueur et l'épaisseur des molécules sont constantes, nous avons observé des molécules individuelles avec des courbures variables indiquant que la molécule est flexible. Nos résultats suggèrent la présence de différents domaines structuraux dans Aida-I, ressemblant à 5 « perles sur une chaîne » dans nos moyennes deux-dimensionnels. À faible concentration de β-octoglucoside, les AIDA-I molécules s'organisent oligomères ressemblant des « araignées » avec « bras » allongés. Ceux-ci sont d'apparence similaire aux monomères d' AIDA -I. Des interactions entre les bras d'oligomères adjacents ont été observées. Elles pourraient correspondre à l'interaction trans-cis de molécules AIDA-I.Dans la deuxième partie de ce mémoire de maîtrise, nous avons observé les molécules de l'Aah. La visualisation de l'Aah a montré que Aah assemble en un complexe six fois symétrique en forme d'anneau de ~ 200 Å de diamètre avec un trou de ~ 160 Å. Étant donné le poids moléculaire mesuré par filtration sur gel de était de 660 kDa, il est probable que les complexes en forme d'anneau observés sont des dodecamères. Aah est la première glycosyltrsanferase bactérienne jusqu'à lors rapportée à assembler en un oligomère. Pris ensemble, notre étude fournit des renseignements précieux sur l'arrangement moléculaire de AIDA-I et Aah et fournit les pierres de construction pour poursuivre des études sur l'interaction AIDA-I entrecellules, ainsi que sur la glycosylation d'AIDA-I par Aah.
Bräutigam, Cornelia [Verfasser], and I. B. [Akademischer Betreuer] Autenrieth. "BamB, BamC und BamE und ihre Bedeutung für die Biogenese der Autotransporter-Adhäsine YadA, Invasin und Intimin / Cornelia Bräutigam ; Betreuer: I. B. Autenrieth." Tübingen : Universitätsbibliothek Tübingen, 2017. http://d-nb.info/1199463523/34.
Full textGailiūnaitė, Ernesta. "Autotransporto triukšmo tyrimai Kėdaniuose." Bachelor's thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100903_081757-16993.
Full textTransport is a major source of urban noise. Automobilization increases, and increases the noise level. The permissible noise levels are exceeded, not only downtown, but quiet in public and urban areas, schools and nurseries - Nursery school and residential areas. For those reasons, interfere with recreation and detrimental to health. The road noise in Kedainiai selected 16 places: schools, nursery - Nursery school, public dormant urban areas, parks, hospitals, residential areas. Compared with the hygiene rule, the results obtained allow to write the findings and suggestions for noise reduction. Reducing motor noise in the dissemination of Kedainiai need for preventive measures and noise reduction. Reduce the amount of parking in the city, equipped with bicycle and pedestrian trails, a greater use of public transport.
Kmitas, Evaldas. "Autotransporto keliama oro cheminė tarša Kelmėje." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110602_120656-97255.
Full textThe volume of vehicle traffic, growing every year, increases the emissions of toxic substances and pollutes the environment. Consequently, the road traffic in Lithuania has increased by 2.5 times over the last decade. Big cities and small towns have noticed the effect of harmful exhaust emissions on the environment and people health most. A large number of chemical sources of air pollution are located near Kelme city: road Riga – Kaliningrad, Kelme – Raseiniai and the main city crossroads, which produces the most significant contaminants. These roads are constantly moving the intense flows of motor vehicles, the part of which falls within the town of Kelme. Therefore the aim of our research was to study the impact of the road traffic on the air quality in Kelme city, to investigate the traffic flows, to measure the concentration of carbon monoxide in the air, theoretically calculate the impact of vehicle age and its operating parameters on the exhaust emissions and its composition. The experimental research revealed the chemical pollution of the vehicles .
Andersson, Ken G. "Combinatorial Protein Engineering Of Affibody Molecules Using E. Coli Display And Rational Design Of Affibody-Based Tracers For Medical Imaging." Doctoral thesis, KTH, Proteinteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-213451.
Full textQC 20170904
Bäcklund, Emma. "Impact of glucose uptake rate on recombinant protein production in Escherichia coli." Doctoral thesis, KTH, Bioprocessteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-34019.
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Kochuparampil, Jumey. "Probing Individual Complexes of Self-Associating Autotransporters by Single Molecule Force Spectroscopy." Thesis, 2013. http://spectrum.library.concordia.ca/977272/16/MSc__Jumey_Kochuparampil.pdf.
Full textSpahich, Nicole Ann. "A Tale of Two Proteins: Insights into the Haemophilus influenzae Hap and Hia Autotransporters." Diss., 2011. http://hdl.handle.net/10161/5002.
Full textNontypeable Haemophilus influenzae (NTHi) is a common commensal in the human nasopharynx that can cause localized respiratory tract diseases such as otitis media, bronchitis, and pneumonia. NTHi adheres to respiratory epithelial cells, a critical step in the process of colonization enabled by bacterial surface adhesive structures called adhesins. One group of NTHi adhesins are autotransporters, proteins that have an N-terminal signal sequence, a C-terminal β-barrel domain, and an internal passenger domain with effector function. The goal of this work was to increase our understanding of two NTHi autotransporters, Hap and Hia.
Hap is a monomeric autotransporter that mediates adherence to epithelial cells and extracellular matrix (ECM) proteins. Hap also self-associates with protein on neighboring bacteria, resulting in bacterial aggregation and microcolony formation. The Hap passenger domain contains the regions responsible for adhesive activity. To define the molecular mechanism of Hap adhesive activity, we crystallized the Hap passenger domain. Characterization of the crystal structure revealed an N-terminal globular domain and a more ordered, prism-like C-terminal domain. Interestingly, Hap crystallized as a multimer, suggesting that Hap-Hap interactions occurred in the passenger domain. Progressive deletions of the β-loops that comprise the C-terminal region disrupted Hap-Hap interactions and led to a defect in bacterial settling. To further support that the C-terminal domain was responsible for Hap-Hap interactions,
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we purified the wild type and truncated passenger domains and conjugated the proteins to latex beads. By light microscopy we visualized bead aggregation when the wild type passenger domain was conjugated to the beads, but not when the truncated passenger domain was conjugated. These results show that the C-terminal portion of the Hap passenger domain is responsible for Hap-Hap interactions leading to multimerization. Hap multimerization could be important in microcolony formation that leads to biofilm formation in vivo.
The ECM binding domain in located in the final 511 amino acids of the Hap passenger domain. To pin-point the region of the ECM protein fibronectin that is recognized by Hap, we spotted small fragments of fibronectin onto nitrocellulose membranes and incubated the membrane with purified Hap passenger domain. Far Western analysis using Hap antibody revealed that the smallest fibronectin region necessary for binding was comprised of the first two type III repeats, FNIII(1-2). To define the regions of Hap responsible for interaction with fibronectin, we mutated motifs in the Hap passenger domain that are important for fibronectin binding in other bacterial proteins. Based on assessment by ELISA, many of the mutations located between amino acids 525-725 caused reduced bacterial binding to fibronectin. However, no mutation totally ablated binding, suggesting that a larger Hap region is involved in fibronectin binding.
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In an additional study, we identified a relationship between Hap levels in the outer membrane and the expression of lipopolysaccharide (LPS) biosynthesis enzymes. Through Western and qPCR analysis, we found that mutation of the rfaF, pgmB, lgtC, kfiC, orfE, rfbP, lsgB and lsgD genes involved in the synthesis of LPS oligosaccharide core in H. influenzae strain Rd/HapS243A resulted in loss of Hap in the bacterial outer membrane and a decrease in hap transcript. In contrast, the same mutations had no effect on outer membrane localization of H. influenzae P5 and IgA1 protease or levels of the p5 or iga1 transcripts, suggesting a Hap-specific effect. Elimination of the HtrA periplasmic protease resulted in a return of Hap to the outer membrane and restoration of wild type levels of hap transcript. We speculate that the lack of certain LPS biosynthesis enzymes causes Hap to mislocalize and accumulate in the periplasm, where it is degraded by HtrA. This degradation then leads to a decrease in hap transcript. lgtC is one of several phase variable LPS biosynthesis genes. Using an antibody against the epitope formed in part by the lgtC gene product, we identified lgtC phase-off bacteria by Western analysis of colony blots. Consistent with our previous observations, in lgtC phase off bacteria Hap was absent from the outer membrane and hap transcript was reduced. By analyzing a lgtC/lic2A double mutant, we found that Hap localization in the outer membrane and hap transcript levels were not related to LPS size but instead to the functions of the LPS synthesis enzymes themselves. This relationship could be beneficial to bacteria in vivo as a way to regulate Hap expression.
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Early models suggested that autotransporters do not require accessory factors for folding and OM insertion. However, mounting recent evidence has suggested that the Bam complex is required for OM localization of most β-barrel proteins, including autotransporters. We studied the role of the Bam complex in OM localization of the trimeric autotransporter Hia. We expressed Hia in E. coli strains with mutations in the Bam complex and found that BamA and BamD were needed for Hia localization, while BamB, BamC, and BamE were not necessary. In further studies, we mutated the C-terminus of Hia and found that the final and third-to-last amino acids were the most important for outer membrane localization.
In summary, this work provides insights into the regulation and adhesive activity of Hap and the outer membrane localization of Hia. We have learned important details about these factors that shed light on aspects of H. influenzae disease and could lead to new antimicrobial therapies.
Dissertation
Chávez, Solís Dulce Yazmín, and Juárez Elí Angélica Silva. "Sistema de Información Contable-Fiscal para una Persona Física dedicada al Autotransporte de Carga en General, Estudio de caso: “Autotransportes Lozada”." Tesis de Licenciatura, 2014. http://hdl.handle.net/20.500.11799/30807.
Full textCharbonneau, Marie-Ève. "Étude de la biogenèse de l'autotransporteur AIDA-I d'Escherichia coli." Thèse, 2012. http://hdl.handle.net/1866/8561.
Full textMonomeric autotransporters, a family of proteins that use the type V secretion pathway, are important mediators of virulence for many bacterial pathogens. Many functions important for host colonization and survival have been described for these proteins. Despite the recognized importance of this family of proteins, the mechanisms that are required for the biogenesis and functionality of monomeric autotransporters still remain poorly understood. The Escherichia coli adhesin involved in diffuse adherence (AIDA-I) is a classical multifunctional autotransporter protein that mediates bacterial aggregation and biofilm formation, as well as adhesion and invasion of cultured epithelial cells. Extracellular domains of autotransporters are responsible for the protein function and fold into a characteristic β-helical structure. We performed a random mutagenesis of the AIDA-I passenger domain in order to identify regions involved in the various phenotypes associated with the expression of this protein. Our study suggests that the passenger domain of AIDA-I possesses a modular organization, which means that AIDA-I is built with individual functional modules. Autotransporter passenger domains can be cleaved from the β-domain and released into the extracellular milieu. However, despite the fact that diverse cleavage mechanisms have been previously described, many autotransporters, like AIDA-I, are cleaved by an unknown mechanism. By monitoring the in vitro refolding and cleavage following by site-directed mutagenesis, we showed that AIDA-I processing is an autocatalytic event that involves two acidic residues. Our results unveil a new mechanism of auto-processing in the autotransporter family. AIDA-I is one of the few glycosylated proteins found in Escherichia coli. Glycosylation is mediated by a specific heptosyltransferase encoded by the aah gene, but little is known about the role of this modification and the mechanism involved. Our findings suggest that Aah represents the prototype of a new large family of bacterial protein O-glycosyltransferases that modify various substrates recognized through a structural motif. Furthermore, we showed that glycosylation occurs in the cytoplasm by a cotranslational mechanism. These observations are unique in bacteria and represent a significant advance in our comprehension of prokaryotic glycosylation. We also showed that glycosylation is required to ensure a normal conformation of AIDA-I and, as a consequence, is necessary for its cell-binding function. The finding that other autotransporters or large adhesin-encoding genes are linked to Aah homologue-encoding genes suggests that glycosylation may be important, if not essential, for the function of these proteins, as for AIDA-I. In conclusion, the results presented in this thesis bring new information about the autotransporter family and also give new insight into the mechanisms that are important for different aspects of the biogenesis of monomeric autotransporters.
Oliver, David C. "Structure/function studies of the Bordetella pertussis autotransporter protein BrkA :." Thesis, 2005. http://hdl.handle.net/2429/16936.
Full textScience, Faculty of
Microbiology and Immunology, Department of
Graduate
Doyle, Matthew Thomas. "Polarity and secretion of Shigella flexneri IcsA: a classical autotransporter." Thesis, 2015. http://hdl.handle.net/2440/98693.
Full textThesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Biological Sciences, 2015.
Côté, Jean-Philippe. "Les autotransporteurs auto-associatifs d’Escherichia coli : de facteurs de virulence à déterminants sociaux." Thèse, 2013. http://hdl.handle.net/1866/10508.
Full textAutotransporters are versatile virulence factors of Gram-negative bacteria and use one of the simplest and most widespread secretion system in bacteria. The name autotransporter originate from the observation that all the information needed for the secretion of the protein is encoded in its own sequence, meaning that autotransporters do not need a specialized secretion apparatus. Many autotransporters are multifunctional proteins and can perform a large variety of functions. The self-associating autotransporters (SAATs), represented by AIDA-I, TibA and Ag43, are such multifunctional proteins and can mediate the adhesion and invasion of epithelial cells, the auto-aggregation of bacteria and the formation of biofilm. Because of these functionalities, SAATs are considered important virulence factors of Escherichia coli. However, there are many differences between the SAATs and we still do not know their exact role for the bacteria. Therefore, we have realized a structure-function study of TibA, the least studied SAAT. Our study showed that TibA is a modular protein and that the functional domain of TibA is composed of two modules: an N-terminal module responsible for auto-aggregation and a C-terminal module responsible for adhesion. Our results showed that the organization of AIDA-I, TibA and Ag43 is different and that the SAATs represent different assemblies of modules. We also observed the modular organization when we analyzed various sequence of aidA, suggesting that the SAATs have evolved by a mechanism of domain shuffling. Not surprisingly, we have found new SAATs in Escherichia coli and in other proteobacteria. Our results also highlighted the importance of auto-aggregation in the functionality of the SAATs. We therefore assessed the mechanism of SAAT-mediated auto-aggregation of bacteria. Our results showed that SAATs mediate auto-aggregation of bacteria through direct SAAT/SAAT interactions and that these interactions were reminiscent of the interactions made by cadherin molecules in eukaryotes. We further observed that the SAATs were involved in homophilic interactions, as it is the case with cadherin molecules. SAATs are part of the few proteins that are glycosylated in Escherichia coli. We therefore characterized the glycosylation of TibA and found that glycosylation of TibA stabilized the protein and allowed the protein to modulate its conformation, resulting in a fully functional protein. Taken together, our results suggest that the SAATs may be cadherin-like molecules by bacteria in order to discriminate between self and non-self. Such an ability to discriminate self from non-self is rarely evoked in bacteria, but could play a role in the organization of multicellular communities.