Dissertations / Theses: 'BIN MECHANISM'

1

Gore, Kiron Pralhad. "Design, fabrication and testing of a special purpose end effector for the task of bin-picking." Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/16954.

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2

Jurak, Igor. "The molecular mechanism of the cytomegalovirus species specificity." Doctoral thesis, [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=981699510.

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3

Fotsing, Kamte Marcellin M. "Electrosynthesis and mechanism of copper(I) nitrile complexes." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974106666.

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4

Lau, Chun-fai Lawrence. "An institutional analysis of the HKSAR government's disciplinary mechanism." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B23294826.

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5

Gwan, Jean-Fang. "The molecular mechanism of multi-ion conduction in K+ channels." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=983151253.

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6

Kresse, Matthias. "Mechanism of liver cell injury by the cytostatic drug melphalan." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975196618.

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7

Gruber, Thomas. "Oscillatory brain activity as underlying neural mechanism of human memory." [S.l. : s.n.], 2002. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9798126.

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8

Alwani, Shariman M. N. "Evaluating the effectiveness of the monetary transmission mechanism in Malaysia." online access from Digital Dissertation Consortium access full-text, 2006. http://libweb.cityu.edu.hk/cgi-bin/er/db/ddcdiss.pl?3232094.

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9

Xin, Yunchang. "Degradation mechanism and surface modification of biomedical magnesium alloy /." access full-text access abstract and table of contents, 2010. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-ap-b30011723f.pdf.

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Thesis (Ph.D.)--City University of Hong Kong, 2010.
"Submitted to Department of Physics and Materials Science in partial fulfillment of the requirements for the degree of Doctor of Philosophy." Includes bibliographical references.

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10

Visinoiu, Alina Mihaela. "Growth mechanism and structure of epitaxial perovskite thin films and superlattices." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967408350.

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11

Mai, Thanh-Tung. "Direct galvanic metallization of insulating substrates mechanism and applications for microstructuring /." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968525792.

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12

Wang, Dapeng. "The mechanism of glucocorticoid induced murine thymocyte and peripheral T cell apoptosis." Doctoral thesis, [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=979813506.

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13

Feller, Andreas. "Reaction mechanism and deactivation pathways in zeolite catalyzed isobutane-2-butene alkylation." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967127483.

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14

Kittsteiner, Thomas. "Applications of mechanism- and auction-design to partnership dissolution and sequential sale." [S.l. : s.n.], 2002. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10605025.

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15

Chow, Ngan-yue Alice. "Flow cytometric analysis of the anticancer mechanism(s) of Chinese medicine, Danshen /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B23234349.

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16

Tse, Lai Yee Lily. "WTO dispute settlement mechanism implementation issues and the way forward /." access abstract and table of contents access full-text, 2008. http://libweb.cityu.edu.hk/cgi-bin/ezdb/dissert.pl?ma-slw-b23454386a.pdf.

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Thesis (M.A.)--City University of Hong Kong, 2008.
"The School of Law, City University of Hong Kong, dissertation." "Programme: MAADR, LW6409A" Title from PDF t.p. (viewed on June 1, 2009) Includes bibliographical references.

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17

Kästner, Johannes. "Biological nitrogen fixation simulation of the reaction mechanism of nitrogenase from first principles /." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971535701.

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18

Hou, Bo. "Mechanism of dpH/TAT [DeltapH/TAT]-dependent protein transport at the thylakoid membrane." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975658646.

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19

Schulte, Uwe. "pH-Gating of inward-rectifier K+ channels (Kir) molecular mechanism and structural implications /." [S.l. : s.n.], 2000. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB8385910.

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20

Bondock, Samir. "Mechanism and synthetic use of Paternò-Büchi reactions spin mapping and photo aldol reactions /." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968091725.

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21

Landes, Nico. "Vitamin E : elucidation of the mechanism of side chain degradation and gene regulatory functions." Phd thesis, [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975679473.

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22

Maillard, Olivier. "DNA damage recognition mechanism of xeroderma pigmentosum group C protein in human nucleotide excision repair /." [S.l.] : [s.n.], 2007. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000253588.

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23

Degefa, Tesfaye Hailu. ""Ion channel (mimetic) sensors" mechanism of charge propagation through thiol-, protein- and dendrimer-modified electrodes /." Doctoral thesis, [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=980218624.

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24

Ganesan, Sundar. "Local protein turnover as a regulatory mechanism of growth and collapse of neuronal growth cones." Doctoral thesis, [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976327376.

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25

Rampp, Markus. "Radiation hydrodynamics with neutrinos stellar core collapse and the explosion mechanism of type II supernovae /." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=960213155.

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26

Cheung, Lin Yung Carol. "Alternative dispute resolution mechanism and the ombudsman system in Hong Kong an evaluation /." access abstract and table of contents access full-text, 2008. http://libweb.cityu.edu.hk/cgi-bin/ezdb/dissert.pl?ma-slw-b22445900a.pdf.

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Thesis (M.A.)--City University of Hong Kong, 2008.
"A dissertation submitted to the School of Law in partial fulfillment of the requirements for the degree of Master of Arts in arbitration and dispute resolution." Title from PDF t.p. (viewed on Apr. 1, 2008) Includes bibliographical references.

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27

Badirujjaman, Syed. "Grain boundary motion under high temperature low cycle deformation : study of mechanism, kinetics and driving force." kostenfrei, 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974934976.

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28

Stimac, Robert. "Macrocyclic Carbon Suboxide Derivatives Novel Potent Inhibitors of the Na,K-ATPase, and their Mechanism of Inhibition /." [S.l. : s.n.], 2005. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11729978.

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29

Atmaoui, Nassima. "Development of pull apart basins and associated structures by the Riedel shear mechanism insight from scaled clay analogue models /." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980651336.

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30

Foerster, Stefanie Anette Erica. "EPR spectroscopic investigation of the active site of [NiFe]-hydrogenase a contribution to the elucidation of the reaction mechanism /." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968375529.

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31

Feilitzsch, Till von. "On the mechanism of photoinduced electron transfer in bridged donor-acceptor systems ferrocenophane-nileblue and rhodamine6G endcapping the DNA duplex /." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972589198.

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32

Mohamed, Ihab Kamal. "Cell and molecular biological and Fluorochrome analysis of the mechanism involved in the Calcium dynamics during exocytosis in Paramecium cells /." [S.l. : s.n.], 2001. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9771243.

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33

Leung, Brian Ming-yuen. ""What is the role of ADR in the existing and future environmental dispute mechanism in Hong Kong?"." access abstract and table of contents access full-text, 2003. http://libweb.cityu.edu.hk/cgi-bin/ezdb/dissert.pl?ma-slw-b18508315a.pdf.

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34

Beck, Eichler-Jonsson Claudia. "Aspects of mitogen-activated protein kinase cascade activation by epidermal growth factor (EGF): kinetics and crosstalk mechanism with tumor necrosis factor Alpha (TNFalpha) /." [S.l. : s.n.], 2002. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10252924.

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35

Beck, Eichler-Jonsson Claudia. "Aspects of mitogen activated protein kinase cascade activation by epidermal growth factor (EGF) kinetics and crosstalk mechanism with tumor necrosis factor [alpha] (TNF[alpha]) /." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965959937.

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36

Tonne, Jörn. "The mechanism of an unusual benzo-benzo photocycloaddition reaction photophysical and photochemical investigation of [3.3] orthocyclophanes with two face-to-face preoriented benzenoid chromophores [[Elektronische Ressource] /." [S.l. : s.n.], 2001. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9381988.

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37

Stimac, Robert. "Macrocyclic carbon suboxide derivates : novel potent inhibitors of the Na,K-ATPase, and their mechanism of inhibition = Makrozyklische Kohlensuboxid-Derivate : neuartige, besonders wirksame Inhibitoren der Na,K-ATPase und ihr Inhibitionsmechanismus /." Konstanz, 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=974308676.

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38

Griesel, Alexa. "Modelling large scale ocean circulation : the role of mixing location and meridional pressure gradients for the Atlantic overturning dynamics." Phd thesis, [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975678671.

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39

Voigt, Anja. "Zur Chemie photolytisch generierter Arylnitrene in Polymermatrizen." Doctoral thesis, [S.l. : s.n.], 1998. http://deposit.ddb.de/cgi-bin/dokserv?idn=955351111.

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40

Velthuis, Paul. "New authentication mechanism using certificates for big data analytic tools." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215694.

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Companies analyse large amounts of sensitive data on clusters of machines, using a framework such as Apache Hadoop to handle inter-process communication, and big data analytic tools such as Apache Spark and Apache Flink to analyse the growing amounts of data. Big data analytic tools are mainly tested on performance and reliability. Security and authentication have not been enough considered and they lack behind. The goal of this research is to improve the authentication and security for data analytic tools.Currently, the aforementioned big data analytic tools are using Kerberos for authentication. Kerberos has difficulties in providing multi factor authentication. Attacks on Kerberos can abuse the authentication. To improve the authentication, an analysis of the authentication in Hadoop and the data analytic tools is performed. The research describes the characteristics to gain an overview of the security of Hadoop and the data analytic tools. One characteristic is that the usage of the transport layer security (TLS) for the security of data transportation. TLS usually establishes connections with certificates. Recently, certificates with a short time to live can be automatically handed out.This thesis develops new authentication mechanism using certificates for data analytic tools on clusters of machines, providing advantages over Kerberos. To evaluate the possibility to replace Kerberos, the mechanism is implemented in Spark. As a result, the new implementation provides several improvements. The certificates used for authentication are made valid with a short time to live and are thus less vulnerable to abuse. Further, the authentication mechanism solves new requirements coming from businesses, such as providing multi-factor authenticationand scalability.In this research a new authentication mechanism is developed, implemented and evaluated, giving better data protection by providing improved authentication.

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41

Stransfeld, Lena. "Analysing the molecular mechanism of growth repression by big brother." Thesis, University of East Anglia, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.533706.

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42

Bakhos, Al Douaihy Dalal. "Implication des lysines acétyl transférases dans les mécanismes ALTernatifs de maintenance des télomères Opposite effects of GCN5 and PCAF knockdowns on the alternative mechanism of telomere maintenance ALT cancer cells are specifically sensitive to lysine acetyl transferase inhibition." Thesis, Sorbonne Paris Cité, 2018. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=2322&f=12888.

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Certaines cellules cancéreuses peuvent utiliser un mécanisme indépendant de la télomérase, connu sous le nom ALT (Alternative Lengthening of Telomeres) pour allonger leurs télomères. Les cellules ALT sont caractérisées par des télomères hétérogènes extrêmement longs et d’autres très courts voire indétectables qui co-localisent avec les corps PML pour former des structures nucléaires appelées APB (ALT-associated PML Bodies), et une fréquence élevée d'échange entre les télomères des chromatides sœurs appelées T- SCE (Telomeric Sister Chromatid Exchange). Bien qu'il soit concevable que la recombinaison homologue soit le mécanisme clé pour le maintien des télomères par la voie ALT, les acteurs moléculaires ne sont pas très bien connus. Nous avons identifié de nouveaux régulateurs potentiellement impliqués dans le mécanisme ALT: PCAF (P300/CBP-associated factor) et GCN5 (General Control Non-derepressible 5), deux lysines acétyl transférases homologues. Elles représentent généralement des facteurs de transcription, cependant, elles peuvent aussi acétyler des protéines non histones. Elles sont mutuellement exclusives dans de multiples complexes y compris le complexe SAGA. Nous avons montré que l’inhibition de ces deux protéines induit des effets opposés sur le phénotype ALT. Bien que l’absence de GCN5 augmentait l'instabilité des télomères et la fréquence des T-SCE et, la sous-expression de PCAF diminuait les T-SCE, la formation des APB et l'instabilité des télomères. Nos résultats suggèrent que dans les cellules ALT GCN5 est présent au niveau de l’ADN télomérique il inhibe la recombinaison entre les télomères et n’affecte pas la formation des APB, contrairement à PCAF qui peut indirectement les favoriser et stimuler aussi la formation des APB. Ensuite, nous avons cherché les mécanismes par lesquels PCAF et GCN5 contribuent au maintien des télomères dans les cellules ALT. Nous avons proposé que la participation de ces deux protéines consiste à réguler le turnover de la protéine télomérique TRF1 via USP22, une déubiquitinase identifiée pour la première fois comme un constituant des APB. En outre, l'intérêt de cibler l’activité de ces lysines acétyl transférase dans les cellules ALT a été testé in vitro en utilisant des inhibiteurs seuls ou combinés à l’irradiation. Nous avons montré que les cellules ALT sont particulièrement sensibles à l'inhibition de l'activité lysine acétyl transférase par l'acide anacardique (AA). Le traitement par cette molécule récapitule l'effet de la sous-expression de PCAF sur le phénotype ALT, suggérant que l’AA défavorise le mécanisme ALT en inhibant l'activité lysine acétyl transférase de PCAF, et non pas celle du GCN5. De plus, l'AA sensibilise spécifiquement les cellules ALT humaines à l’irradiation en comparant aux cellules télomérase-positives, prouvant que l'inhibition de l'activité des lysines acétyl transférases peut être un outil pour traiter les cellules ALT en augmentant l'efficacité de la radiothérapie
Some cancer cells can use a telomerase-independent mechanism, known as alternative lengthening of telomeres (ALT), to elongate their telomeres. ALT cells present unusual characteristics: extremely long and heterogeneous telomeres that colocalize with PML bodies to form nuclear structures called ALT-associated PML Bodies (APB), and high frequency of exchange events between sisters chromatid telomere referred to as Telomeric Sister Chromatid Exchange (T-SCE). Although it is agreed that homologous recombination is the key mechanism allowing the maintenance of the telomeres of ALT cells, the molecular actors involved are not yet known. We identified new actors potentially involved in the ALT mechanism: general control non-derepressible 5 (GCN5) and P300/CBP-associated factor (PCAF). Although they represent transcription factors, they can also acetylate non-histone proteins. They are mutually exclusive subunits in SAGA-like complexes. Here, we reveal that down regulation of GCN5 and PCAF had differential effects on some phenotypic characteristics of ALT cells. While GCN5 knockdown increased T-SCE and telomere instability, PCAF knockdown decreased T-SCE, APBs formation and telomere instability. GCN5 and PCAF knockdowns had thus differential effects on ALT, up-regulating it or down-regulating it respectively. Our results suggest that in ALT cells GCN5 is present at telomeres and opposes telomere recombination and does not affect the formation of APBs, unlike PCAF which may indirectly favour them and stimulate the APB formation. Then we evaluate the mechanisms by which PCAF and GCN5 contribute to the maintenance of telomeres in ALT cells. We have proposed that the participation of these two proteins should involve regulating the turnover of the telomeric protein TRF1 via USP22, a deubiquitinase identified for the first time as a component of APBs. In addition, the interest of targeting lysine acetyl transferase activities in ALT cells to oppose the maintenance of telomeres was subsequently tested in vitro using inhibitors alone or combined to irradiation. We have shown that ALT cells are particularly sensitive to the inhibition of acetyltransferases activities using Anacardic Acid (AA). AA treatment recapitulates the effect of PCAF knockdown on several ALT features, suggesting that AA decreased the ALT mechanism through the inhibition of lysine transferase activity of PCAF, but not that of GCN5. Furthermore, AA specifically sensitizes human ALT cells to radiation as compared to telomerase-positive cells suggesting that the inhibition of lysine acetyltransferases activity may be used to increase the radiotherapy efficiency against ALT cancers

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43

Zaccara, Sara. "Translational control mechanisms in the p53 response network." Doctoral thesis, Università degli studi di Trento, 2015. https://hdl.handle.net/11572/369104.

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The sequence-specific transcription factor p53 is considered a master gene of cellular responses to homeostasis changes. It is also a prominent tumor suppressor gene with the title of â€œguardian of the genomeâ€ . The increasing number of transcriptome analyses in cell lines treated with different agents activating p53, continues to add complexity to the vast transcriptional networks p53 regulates. To investigate mRNA translational control as an additional dimension of p53-directed gene expression responses, we performed translatome analyses upon its activation either by different agents or cellular contexts. Considered as a proxy for the proteome, the translatome allows us to characterize the translational status of each mRNA, independently from transcriptional modulations, and to evaluate the implications or correlations of changes in relative mRNA translation efficiencies with the phenotypic outcome. We first performed treatment-specific translatome profiling in MCF7 cells upon Doxorubicin and Nutlin-3a treatments. Among translated genes, we detected the presence of translationally enhanced mRNAs with a virtually absent transcriptional modulation; those genes were enriched for apoptotic functions, suggesting that the apoptotic phenotype might be controlled not only at the transcriptional, but also at the translational level. Seeking mechanisms underlying the mRNAs translational rate upon p53 activation, we identified the modulation of six RNA-binding proteins, where hnRNPD (AUF1) and CPEB4 are direct p53 targets, whereas SRSF1, DDX17, YBX1 and TARDBP are indirect targets, modulated at the translational level in a p53-dependent manner. In detail, we demonstrated the contribution of at least two p53-dependent translational mechanisms related to YBX1 translational repression, suggesting the presence of a controlled regulon at the crossroad of YBX1 mRNA translation. Given our finding that apoptotic genes appear to be controlled by p53 also at the translational level, we decided to explore whether mRNAs translational control mechanisms are indeed an additional checkpoint to the phenotype. To this aim, we performed a cell-type specific translatome study upon Nutlin-3a treatment, a drug with evident therapeutic prospective. SJSA1, HCT116 and MCF7 cells were chosen as they exhibit different cellular responses to Nutlin-3A (cell cycle arrest, apoptosis, or both, respectively). Our preliminary data suggests that translational modulation can affect the complex process of cell fate choice upon p53 activation. Indeed, a lack of overlap among genes differentially modulated at the translational level was evident. Motif search analysis at the 5â€™- and 3â€™-UTR of those genes highlighted the presence of different motifs in the three cell lines and the specific correlation of a C-rich motif with the apoptotic phenotype. Preliminary data on this motif will be presented and discussed. Two independent projects will be presented as appendixes, both of them related to the general idea that more than one factor may determine the p53 response. Starting from the analysis of possible p53 interactions with other transcriptional co-factors, we investigated the cooperative interaction between p53 and NFÎºB. For the second project, combining data previously obtained by means of yeast-based p53 transactivation assays, we developed an algorithm, p53retriever, to scan DNA sequences and thus identify p53 response elements and classify them based on their transactivation potential.

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44

Zaccara, Sara. "Translational control mechanisms in the p53 response network." Doctoral thesis, University of Trento, 2015. http://eprints-phd.biblio.unitn.it/1560/1/2015_06_03_PhD_Thesis_SZ_final.pdf.

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The sequence-specific transcription factor p53 is considered a master gene of cellular responses to homeostasis changes. It is also a prominent tumor suppressor gene with the title of “guardian of the genome”. The increasing number of transcriptome analyses in cell lines treated with different agents activating p53, continues to add complexity to the vast transcriptional networks p53 regulates. To investigate mRNA translational control as an additional dimension of p53-directed gene expression responses, we performed translatome analyses upon its activation either by different agents or cellular contexts. Considered as a proxy for the proteome, the translatome allows us to characterize the translational status of each mRNA, independently from transcriptional modulations, and to evaluate the implications or correlations of changes in relative mRNA translation efficiencies with the phenotypic outcome. We first performed treatment-specific translatome profiling in MCF7 cells upon Doxorubicin and Nutlin-3a treatments. Among translated genes, we detected the presence of translationally enhanced mRNAs with a virtually absent transcriptional modulation; those genes were enriched for apoptotic functions, suggesting that the apoptotic phenotype might be controlled not only at the transcriptional, but also at the translational level. Seeking mechanisms underlying the mRNAs translational rate upon p53 activation, we identified the modulation of six RNA-binding proteins, where hnRNPD (AUF1) and CPEB4 are direct p53 targets, whereas SRSF1, DDX17, YBX1 and TARDBP are indirect targets, modulated at the translational level in a p53-dependent manner. In detail, we demonstrated the contribution of at least two p53-dependent translational mechanisms related to YBX1 translational repression, suggesting the presence of a controlled regulon at the crossroad of YBX1 mRNA translation. Given our finding that apoptotic genes appear to be controlled by p53 also at the translational level, we decided to explore whether mRNAs translational control mechanisms are indeed an additional checkpoint to the phenotype. To this aim, we performed a cell-type specific translatome study upon Nutlin-3a treatment, a drug with evident therapeutic prospective. SJSA1, HCT116 and MCF7 cells were chosen as they exhibit different cellular responses to Nutlin-3A (cell cycle arrest, apoptosis, or both, respectively). Our preliminary data suggests that translational modulation can affect the complex process of cell fate choice upon p53 activation. Indeed, a lack of overlap among genes differentially modulated at the translational level was evident. Motif search analysis at the 5’- and 3’-UTR of those genes highlighted the presence of different motifs in the three cell lines and the specific correlation of a C-rich motif with the apoptotic phenotype. Preliminary data on this motif will be presented and discussed. Two independent projects will be presented as appendixes, both of them related to the general idea that more than one factor may determine the p53 response. Starting from the analysis of possible p53 interactions with other transcriptional co-factors, we investigated the cooperative interaction between p53 and NFκB. For the second project, combining data previously obtained by means of yeast-based p53 transactivation assays, we developed an algorithm, p53retriever, to scan DNA sequences and thus identify p53 response elements and classify them based on their transactivation potential.

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45

Muraro, Lucia. "Studies of Botulinum Neurotoxins Mechanism of Action." Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3425607.

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Botulinum neurotoxins (7 serotypes of BoNTs, named from A to G) and tetanus neurotoxin (TeNT) are the most powerful clostridial toxins (CNTs). They are responsible for botulism and tetanus respectively. TeNT and BoNTs bind to peripheral nerve terminals and inhibit neurotransmitter release from presynaptic neuronal cells by proteolytic cleavage of proteins involved in the fusion of synaptic vesicles with the cell membrane. BoNTs act at the level of Peripheral Nervous System (PNS) causing flaccid paralysis whereas TeNT acts at the level of Central Nervous System (CNS) causing spastic paralysis. In particular BoNT A cleaves and disables SNAP25 (synaptosome-associated protein 25), impairing the release of acetylcholine at neuromuscular junction. Structurally, CNTs are composed of two polypeptide chains linked by a single disulphide bond: the 50 kDa Light Chain (LC), which acts in the cytosol as a metalloprotease; and the 100 kDa Heavy chain, which includes a translocation domain (HN) and a receptor binding domain (HC). The three functional domains are structurally distinct and arranged in a linear fashion, such that there is no contact between the LC and HC domain. HC is further composed of two distinct subdomains HCN and HCC. These neurotoxins act at femtomolar concentration and the high affinity binding is due to multiple binding sites, either for membrane ganglioside and neuronal specific membrane proteins. BoNT/A binds to SV2 (synaptic vesicle 2) and to the ganglioside GT1b. It was thought that these two binding sites were located one in HCN subdomain and the other in the HCC subdomain. HCN share some sequence homology with lectins so it was a good candidate to bind ganglioside. Recently by crystallographic analysis it has been shown that both the protein receptor and ganglioside sites of BoNT/B are in the HCC domain. Due to the high homology between all CNTs it is likely that also the SV2 and GT1b sites are in the BoNT A HCC domain. If this is the case the role of N-terminal subdomain of BoNT A is still unknown. The aim of this project is to investigate the role of HCN in the binding of BoNT A to the plasma membrane. It is important to notice that the sequence of this toxin portion is conserved among all CNTs. The sequence of BoNT/A coding for the HCN domain (aa from 855 to 1093) has been cloned as His-Tag fusion protein, and fused to the Enhanced Green Fluorescent Protein (EGFP) and to the monomeric cherry red fluorescent protein (mCherry). By fluorescent microscopy observations we have shown that both the fluorescent chimera were able to bind to the plasma membrane of epithelial and neuronal cells. The fluorescent HCN domain remains at the plasma membrane during incubation times that allow the internalization of whole binding domain, HC. The fluorescent staining is not homogenous on the plasma membrane but is enriched in bright spots. For TeNT binding a role of lipid raft have been establish but for BoNTs the question seems to be still open. Ours data show that the sphingomyelin binding toxin lysenin, colocalized with HCN staining and treatment with sphingomyelinase diminished the HCN binding on epithelial cells. Moreover, in dot blot analysis HCN was able to directly interact with anionic lipid in particular phosphatidylinositol 5 phosphate (PI(5)P). A role for negative charged lipid in the binding of BoNTs and TeNT to lipid bilayer, it was already suggested; our hypothesis is that the N-terminal portion of the binding domain is able to bind anionic lipid in the environment of lipid raft. We suggest that these additional interactions with the membrane surface may play the role of positioning the toxin on the membrane surface ready for membrane insertion.

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Oppermann, Sina [Verfasser], and Carsten [Akademischer Betreuer] Culmsee. "Targeting Bid for mitoprotection - Bid crystallization, new mechanisms and inhibitory compounds / Sina Oppermann. Betreuer: Carsten Culmsee." Marburg : Philipps-Universität Marburg, 2014. http://d-nb.info/1052995063/34.

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De, Santis Micaela. "Bacterial lipoproteins: sorting mechanisms and biotechnological applications." Doctoral thesis, Università degli studi di Trento, 2015. https://hdl.handle.net/11572/367625.

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The mechanism responsible for lipoprotein sorting is conserved among bacterial species. However, the final destination of lipoproteins may vary among species. In some species lipoproteins are surface-exposed while in others they are associated to the outer membrane but facing the periplasm. To elucidate whether the difference in lipoprotein location is intrinsic to lipotrotein sequence/structure or rather is due to specific transport systems present in some bacterial species and absent in others lipoproteins were expressed in different species and their compartmentalization analyzed. The data seem to indicate that the destiny of lipoproteins depends upon specific structural signatures but the recognition of such signatures can be species-specific. Interestingly, lipoproteins can be exploited as chaperones to deliver foreign proteins to the outer membrane compartment.

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Jano, Rubina. ""Mentors' perception of the effectiveness of the Big Brother Big Sister mentor training programme"." Thesis, University of the Western Cape, 2008. http://hdl.handle.net/11394/2791.

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Magister Psychologiae - MPsych
Mentoring has gained a great deal of popularity across various professional fields and disciplines over the past few years. More recently, planned mentoring has become an important form of intervention with young people (Philip, 2003). Although mentoring can be an effective strategy for dealing with youth, the mentoring is only as good as the relationship that develops out of the process between mentors and mentees and the match that is made between the two parties. The number of mentor programmes that is running continues to grow yet the quality of these programmes remains unknown as this area lacks agreed upon sets of standards and / bench marks that could be used to determine the effectiveness of these programmes (Sipe, 1988 -1995). The primary aim of this study is to evaluate the mentors' perceptions of the effectiveness of a mentor training programme run by Big Brother Big Sister South Africa.
South Africa

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Vuckovic, Ana-Marija. "Unraveling the mechanism of ferroptosis." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3422357.

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Ferroptosis, a form of regulated cell death (RCD), has been recently reported to be primed by missing activity of the ubiquitous selenoperoxidase glutathione peroxidase 4 (GPx4). GPx4 catalyzes a glutathione (GSH)-dependent reduction of membrane hydroperoxides to corresponding alcohols. Since ferroptosis is executed by lipid peroxidation, oxygen, polyunsaturated fatty acids (PUFA), and iron are necessary constraints. Furthermore, since phospholipid hydroperoxides (PL-OOH) have a key role in membrane lipid peroxidation –i.e. their decomposition generates radicals in the membranes- GPx4-mediated regulation of ferroptosis is consistent with both, the mechanisms of lipid peroxidation and protection which have been finely elucidated in vitro in the last forty years of the XX century. In this study, we used as a suitable model of ferroptotic cell death, that primed by erastin in HT1080 cells. Erastin, by preventing cystine import, in these cells decreases the cellular level of GSH and, consequently, GPx4 activity. On this model, we disclosed a critical constraint permitting membrane lipid oxidation and therefore ferroptosis execution. Unexpectedly, we observed that modulating the electron flow through the mitochondria respiratory chain, is indeed unsuccessful in modulating ferroptosis sensitivity. For this indispensable function we identified, instead, the activity of mitochondrial alpha-keto acid dehydrogenases. The deduced mechanism we propose is the formation of O2•- during re-oxidation of dihydrolipoate in the last step of the oxidative decarboxylation, a reaction, already observed in isolated mitochondria. In relation to ferroptosis, we propose that it is the HO2• that generates a carbon centered radical in a PUFA, which, following oxygen addiction and stabilization by hydrogen transfer, forms a PL-OOH. We also studied the mechanisms underlying the inhibition of GPx4 by a prototype of electrophile: (1S,3R) RSL3. This study allowed to disclose the protein 14-3-3 epsilon as an adaptor protein necessary to achieve GPx4 inactivation by (1S,3R) RSL3. By these observations, we clarified the requirements for GPx4 inactivation by electrophiles, which, in vivo is supposed to have a regulatory role. Further, we provided evidence that the ‘inactivation-permitting activity’ of 14-3-3 epsilon on GPx4 is redox regulated by thiol-disulphide transition. This links inhibition by electrophiles to intracellular redox status. This set of new information contributes to the view of cell death by ferroptosis as intrinsically connected to aerobic life through a fine modulation of specific metabolic events. It is an amazing thought that electron transitions between oxygen and iron permits in aerobic organism both, life and death. The latter, therefore, comes up as a fundamental component of aerobic life.

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CAROTTI, MARCELLO. "Mechanism of ribosomal recruitment of initiator tRNA in bacteria." Doctoral thesis, Università degli Studi di Camerino, 2008. http://hdl.handle.net/11581/401875.

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Initiation of mRNA translation in prokaryotes requires the small ribosomal subunit (30S), three initiation factors, IF1, IF2 and IF3, initiator tRNA (fMet-tRNAfMet) and the large ribosomal subunit (50S). During initiation, the 30S ribosomal subunit interacts with the three factors and binds in a presumably random manner fMet-tRNAfMet and mRNA. This initially formed 30S pre-initiation complex is a kinetic intermediate of the stable 30S initiation complex which is formed upon base pairing of the anticodon of fMet-tRNAfMet and the intiation codon of the mRNA in the P-site. In a subsequent step the 50S subunit binds to the 30S initiation complex giving rise to a 70S initiation complex. During this step, a molecule of GTP bound to IF2 is hydrolyzed, the initiation factors are released from the ribosome and fMet-tRNAfMet is stabilized in the P site ready to enter in the elongation phase of translation. In turn, each of these major steps involves numerous elemental steps, whose sequence and timing are largely unknown. How the fMettRNAfMet is bound to the ribosome during the assembly of the initiation complex is one of the many questions still remaining open. According to the classical model, IF2 acts as a carrier of fMet-tRNAfMet to the ribosome. An alternative model predicts that the IF2, prebound to the 30S subunit awaits the arrival of fMet-tRNAfMet with which it interacts only at the ribosomal surface. This work presents results of a kinetic analysis of binding to the 30S subunit of various ribosomal ligands (Initiation Factors, fMet-tRNAfMet, mRNA), performed with fast kinetic techniques (rapid filter binding, fluorescence stopped flow). The data obtained strongly support the model in which IF2 is not a fMettRNAfMet carrier. The elemental rate constants determined here give us a more detailed description of the process of 30S initiation complex assembly, of the interplay of the various ribosomal ligands and of the functional significance of different structural modules of IF2.

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