Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1979. / Bibliography: leaves 146-150. / by James Francis Scheimer. / Ph.D.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24833号 / 医博第5001号 / 新制||医||1067(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 生田, 宏一, 教授 上野, 英樹, 教授 濵﨑, 洋子 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

[pt] Na clínica contemporânea, cada vez mais os psicanalistas têm se defrontado com pacientes que apresentam um profundo sentimento de vazio, expresso por meio de sensações de inadequação, não existência e futilidade. A presença desses pacientes que colocam em xeque a primazia da psicanálise clássica não pode mais ser considerada uma exceção à regra. Nesse sentido, o presente trabalho tem como objetivo investigar a noção de clivagem psíquica bem como o manejo clínico da regressão no processo analítico. O escopo deste trabalho baseia-se nas contribuições seminais do campo psicanalítico a partir de Freud, Sándor Ferenczi, D. W. Winnicott, René Roussillon e demais comentadores contemporâneos. Para alcançar os objetivos propostos, a pesquisa foi dividida em dois capítulos teóricos e um teórico-clínico. O primeiro capítulo refere-se à compreensão do impacto da qualidade relacional exercida nos estágios primitivos da constituição subjetiva. No segundo capítulo, é apresentado o desenvolvimento da teoria do trauma privilegiando o mecanismo de clivagem psíquica adotado diante do excesso pulsional no âmbito da virada metapsicológica de 1920. No terceiro capítulo teórico-clínico, é apresentado a regressão no processo analítico que acompanha as tentativas de elaboração de traumas primitivos que se apresentam aquém das capacidades de representação e simbolização. Com o propósito de ilustrar a articulação entre a teoria psicanalítica apresentada e a clínica, foi apresentado um fragmento clínico em que é possível identificar elementos relacionados à discussão proposta. Consideramos que o processo analítico com esses pacientes deve ocorrer pelas vias da regressão e da confiança aos cuidados do analista. / [en] In contemporary clinical practice, psychoanalysts are increasingly encountering patients who exhibit a profound sense of emptiness, expressed through feelings of inadequacy, non-existence, and futility. The presence of these patients, challenging the primacy of classical psychoanalysis, can no longer be considered an exception to the rule. Accordingly, this present work aims to investigate the notion of cleavage as well as the clinical management of regression in the analytic process. This work draws on seminal contributions from the psychoanalytic field, encompassing perspectives from Freud, Sándor Ferenczi, D. W. Winnicott, René Roussillon, and other contemporary commentators. To achieve the proposed objectives, the research was divided into two theoretical chapters and one theoretical-clinical chapter. The first chapter focuses on understanding the impact of relational quality in the primitive stages of subjective constitution. The second chapter presents the development of trauma theory, emphasizing the mechanism of cleavage adopted in response to instinctual excess within the metapychological shift of the 1920s. The third theoretical-clinical chapter explores the regression within the analytic process, accompanying attempts to elaborate on primitive traumas that challenge the capacities for representation and symbolization. To illustrate the connection between the presented psychoanalytic theory and clinical practice, a clinical fragment is provided, wherein elements related to the discussed topics can be identified. We assert that the analytic process with these patients must proceed through paths of regression while fostering trust in the analyst s care.

Photo sensitizers showing visible light induced DNA cleavage activity are of current importance for medicinal applications related to photodynamic therapy (PTD) considering greater skin penetration of light near 700 nm. While organic molecules and complexes of 4d-5d metal ions are extensively studied for their DNA photo-damage properties in UV and visible light, the chemistry of 3D metal complexes showing visible light-induced DNA cleavage activity is relatively unexplored efforts have been made in this thesis work to design new ternary copper (II) complexes having a-amino acids Such copper (II) complexes with tunable coordination geometry could find potential applications in PDT. Ternary Copper (II) complexes containing L-methionine, S-methy1-L-cysteine and phenanthroline bases are prepared and characterized. They display DNA binding and visible light induced DNA cleavage activity. An enhancement of the DNA cleavage activity is observed for analogous ternary copper (II) complexes contained L-lysine with a pendant cationic amine moiety as a photo-induced DNA Cleavage activity using binary and ternary copper (II) complexes of L-arginine and phenanthroline bases. We have observed AT selective DNA binding and visible light –induced DNA cleavage activity. The crescent-shaped bis-arginine Copper (II) complex mimics the natural antiviral antibiotic netropsin. T o investigate the role of the pendant groups of the amino acids, we have explored the DNA binding and DNA cleavage activity of analogues L-glutamine and L-asparagine complexes. We have prepared ternary copper (II) complexes containing two photosensitizers, viz., L-tryptophan (L-trp) and dipyridoquininoxaline/dipyridophenazine to achieve double strand breaks forming linear DNA. Complex [Cu(L-trp)(dppz)(H2O)+ shows a stacking arrangement of the indole and dppz rings giving a separation that fits with the base pair separation of ds-DNA. Photosensitizes in these complexes approach two different complementary stands of the ds-DNA, leading to double strand breaks and formation of linear DNA. Mechanistic studies on the DNA photocleavage reactions reveal the formation of singlet oxygen(1O2)species by a type-II pathway in preference to the hydroxyl radical generation. A process leading to an efficient DNA cleavage activity on visible light irradiation. The observation of sequence selectivity and double strand DNA cleavage on red light exposure by national design of the complexes is significant considering importance of the results in the chemistry of photodynamic therapy of cancer. The results of this dissertation open up new avenues for designing and developing 3d metal-based photosensitizers with potential utility in nulcleic acid chemistry.

In bacteria, nucleoid associated proteins (NAPs) represent a prominent group of global regulators that perform the tasks of genome compaction, establishing chromosomal architecture and regulation of various DNA transactions like replication, transcription, recombination and repair. HU, a basic histone like protein, is one of the most important NAPs in Eubacteria. Mycobacterium tuberculosis produces a homodimeric HU (MtbHU), which interacts with DNA non-specifically through minor groove binding. Exploration for essential genes in Mtb (H37Rv) through transposon insertion has identified HU coding gene [Rv2986c, hupB; Gene Id: 15610123; Swiss-Prot ID: P95109)] to be vital for the survival and growth of this pathogen. MtbHU contains two domains, the N-terminal domain which is considerably conserved among the HU proteins of the prokaryotic world, and a C–terminal domain consisting of Lys-Ala rich multiple repeat degenerate motifs. Sequence analysis carried out by the thesis candidate showed that MtbHU exhibits 86 to 100 percent identity within the N-term region among all the mycobacterium species and some of the members of actinobacteria, including important pathogens like M. tuberculosis, M. leprae, M. ulcerans, M. bovis, Nocardia; while C term repeat region varies relatively more. This strikingly high cross species identity establishes the MtbHU N-terminal domain (MtbHUN) as an important representative structural model for the above mentioned group of pathogens. The thesis candidate has solved the X-ray crystal structure of MtbHUN, crystallized in two different forms, P2 and P21. The crystal structures in combination with computational analyses elucidate the structural details of MtbHU interaction with DNA. Moreover, the similar mode of self assembly of MtbHUN observed in two different crystal forms reveals that the same DNA binding interface of the protein can also be utilized to form higher order oligomers, that HU is known to form at higher concentrations. Though the bifunctional interface involved in both DNA binding and self assembly is not akin to a typical enzyme active site, the structural analysis identified key interacting residues involved in macromolecular interactions, allowing us to develop a rationale for inhibitor design. Further, the candidate has performed virtual screening against a vast library of compounds, and design of small molecules to target MtbHU and disrupt its binding to DNA. Various biochemical, mutational and biological studies were performed in the laboratory of our collaborator Prof. V. Nagaraja, MCBL, IISc., to investigate these aspects. After a series of iterations including design, synthesis and validation, we have identified novel candidate molecules, which bind to MtbHU, disrupt chromosomal architecture and arrest M. tuberculosis growth. Thus, the study suggests that, these molecules can serve as leads for a new class of DNA-interaction inhibitors and HU as a druggable target, more so because HU is essential to Mtb, but absent in human. Our study proposes that, targeting the nucleoid associated protein HU in Mtb can strategize design of new anti-mycobacterial therapeutics. Perturbation of MtbHU-DNA binding through the identified compounds provides the first instance of medium to small molecular inhibitors of NAP, and augurs well for the development of chemical probe(s) to perturb HU functions, and can be used as a fundamental chemical tool for the system level studies of HU-interactome. Section I: “Crystal structure of Mycobacterium tuberculosis histone like protein HU and structure based design of molecules to inhibit MtbHU-DNA interaction: Leads for a new target.” of this thesis presents an elaborate elucidation of the above mentioned work. The candidate has additionally carried out structure based computational and theoretical work to elucidate the interaction of amino acid based metal complexes which efficiently bind to DNA via minor-groove, major-groove or base intercalation interaction and display DNA cleavage activity on photo-irradiation. This understanding is crucial for the design of molecules towards Photodynamic Therapy (PDT). PDT is an emerging method of non-invasive treatment of cancer in which drugs like Photofrin show localized toxicity on photoactivation at the tumor cells leaving the healthy cells unaffected. The work carried out in our group in close collaboration with Prof. A.R. Chakravarty of Inorganic and Physical Chemistry Department elaborates the structure based design of Amino acid complexes containing single Cu (II), such as [Cu(L-trp)(dpq)(H2O)]+ , [Cu (L-arg) 2](NO3)2 , Amino acid complexes containing oxobridged diiron Fe(III), such as [{Fe(L-his)(bpy)}2(μ-O)](ClO4)2 , [{Fe(L-his)(phen)}2(μ-O)](ClO4)2 , and Complexes containing Binuclear Cu(II) coordinated organic moiety, such as [{(dpq) CuII}2(μ-dtdp)2], which bind to DNA through minor groove/major groove/base intercalation interactions. Docking analysis was performed with the X-ray crystallographic structure of DNA as receptor and the metal complexes as ligands, to study the mode of binding to DNA and to understand the possible mode of DNA cleavage (single/double strand) when activated with laser. Section II: “Structure based computational and theoretical analysis of metal coordinated complexes containing amino acids and organic moieties designed for photo induced DNA cleavage” of this thesis presents a detailed presentation of the above mentioned work.

Scorpionate and terpyridine ligands are of importance in inorganic chemistry for their metal-binding properties. Tris-pyrazolylborate (Scorpionate) ligands that show facial binding mode and steric protection have been extensively used to synthesize complexes modeling the active site structure and biological function of various metalloproteins and as catalysts in C-H and NO activation and carbine transfer reactions. Terpyridine and modified terpyridine ligands showing meridional binding mode have been used in bioinorganic chemistry where Pt-terpyridine complexes are known to inhibit the activity of thiordoxin reductase (TrxR) besides showing interaction with G-quadruplex. The thesis work stems from our interest to use these ligand systems to design and prepare new 3-d metal-based photodynamic therapeutic (PDT) agents to explore their visible light-induced DNA cleavage activity and photocytotoxicity. Efforts have been made in this thesis work to design and synthesize Co(II) and Cu(II) complexes having scorpionate (Tpph) abd terpyridine (tpy) ligands. Ternary 3d-metal complexes having Tpph and planar phenanthroline bases have been synthesized and structurally characterized. The steric encumbrance of Tpph has led to the reduction in chemical nuclease activity along with enhanced photo-induced DNA cleavage activity, particularly of the Cu(II) and Co(II) complexes. The Co(II), Cu(II) and Zn(II) complexes of Tpph and a pyridyl ligand having a photoactive naphthalilmide moiety show molecular light-switch effect on binding to calf thymus DNA or BSA protein. The complexes do not show any chemical nuclease activity. The Cu(II) complex shows significant DNA cleavage activity in red light. The Co(II) complex displays significant photocytotoxicity in UV-A light. Ternary Cu(II) complexes of ph-tpy and heterocycylic bases are prepared and their DNA binding and cleavage activity studied. The complexes are avid binders to CT-DNA. The dipyridoquinoxaline (dpq) and dipyridophenazine (dppz) complexes are photocleavers of DNA in visible light. A significant enhancement in cytotoxicity in HeLa cancer cells is observed on exposure of the dppz complex to light. The binary Cu(II) complexes are also prepared to reduce the dark toxicity using phenyl and pyrenyl substituted terpyridine ligands. The pyrenyl substituted complex shows DNA cleavage activity in the visible light, low dark toxicity and unprecedented photocytotoxicity in visible light. The copper(II) complexes generally show dark cellular toxicity due to the presence of reducing thiols. The present terpyridine copper(II) complex having pendant pyrenyl moiety shows significant PDT effect that is similar to that of the PDT drug Photofrin. Binary Co(II) complexes show efficient DNA cleavage activity in visible light, significant photocytotoxicity in visible light and cytosolic uptake behaviour. Considering the bio-essential nature of the cobalt and copper ions, the present study opens up new strategies for designing and developing 3d-metal-based photosensitizers for their potential applications in PDT.

This thesis employs the globalization and integration-demarcation cleavage theory formulated by Huttar [2014] and Kriesi [2012], conception of populism formulated by Mudde [2017] and draws on Gramscian conception of civil society and hegemony. Aim of this thesis is to build a model of causal influence of globalization on cleavage and on populism, as was suggested by Hutter [2014]. After building this model, the aim is to explore how this theoretical relationship hold's over the 30 years since 90's, when the connection between globalization and new sociocultural cleavage had been theoretically suggested. For this model I am using KOF Globalization Index, European Values Survey datasets and Authoritarian Populism Index constructed and published by Timbro in years 1990, 1999, 2008 and 2017. This model is built on a dataset containing 38 countries on European continent or being a candidate country for EU. I am elaborating Hutter's theoretical suggestion and framing it in Gramscian conception of civil society. This allows me to suggest that populists are using organic crisis in a society to attract people who feel disjointed from current hegemonical elite and to create counterhegemony. The theory is, that globalization increases the tension between winners and losers of globalization sides of cleavage...

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Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The synthesis of a range of siloxane functionalized Ru(arene)Cl(N,N) complexes allowing for the synthesis of novel MCM-41 and SBA-15 immobilized ruthenium(II) catalysts, is described in this thesis. Two distinctly different approaches were envisaged to achieve successful heterogenization of these siloxane functionalized complexes. Condensation of the siloxane functionalized complexes, C2.4-C2.6 (siloxane tether attached to imine nitrogen) and C3.5-C3.7 (siloxane tether via the arene ring), with the surface silanols of the synthesized silica support materials MCM-41 and SBA-15, afforded immobilized catalysts IC4.1-IC4.6 (siloxane tether attached to imine nitrogen) and IC4.7-IC4.12 (siloxane tether via the arene ring). Model and siloxane functionalized complexes C2.1-C2.6 were prepared by the reaction of diimine Schiff base ligands L2.1-L2.6 with the [Ru(p-cymene)2Cl2]2 dimer. A second, novel, approach involved the introduction of the siloxane tether on the arene ligand of the complex. Cationic arene functionalized Ru(arene)Cl(N,N) complexes, C3.1-C3.4, were prepared with varying N,N ligands including bipyridine and a range of diimine ligands, with either propyl or diisopropyl(phenyl) substituents at the imine nitrogen (greater steric bulk around the metal center). The reaction of these propanol functionalized complexes with 3-(triethoxysilyl)propyl isocyanate, afforded urethane linked siloxane functionalized complexes C3.5-C3.8, where the siloxane tether is attached to the arene ring of the complex. The complexes were fully characterized by FT-IR spectroscopy, NMR (1H and 13C) spectroscopy, ESI-MS analysis and microanalysis. Suitable crystals for the alcohol functionalized complex C3.1 were obtained and the resultant orange crystals were analyzed by single crystal XRD. The heterogenized catalysts, IC4.1-IC4.12, were characterized by smallangle powder X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), thermal gravimetric analysis (TGA), inductively coupled plasma optical emission spectroscopy (ICP-OES) and nitrogen adsorption/desorption (BET) surface analysis to name but a few. ICP-OES allowed for direct comparison of the model and immobilized systems during catalysis ensuring that the ruthenium loadings were kept constant. The application of the model complexes C2.1-C2.3 and C3.1-C3.3, as well as their immobilized counterparts, IC4.1-IC4.12, as catalyst precursors in the oxidative cleavage of alkenes (1-octene and styrene), were investigated. The proposed active species for the cleavage reactions was confirmed to be RuO4 (UV-Vis spectroscopy). In general it was observed that at lower conversions, aldehyde was formed as the major product. Increased reaction times resulted in the conversion of the formed aldehyde to the corresponding carboxylic acid. For the oxidative cleavage of 1-octene using the systems with the siloxane tether attached to the imine nitrogen, the immobilized systems outperformed the model systems in all regards. Higher conversions and selectivities of 1-octene towards heptaldehyde were obtained when using immobilized catalysts IC4.1-IC4.6, as compared to their non-immobilized model counterparts (C2.1-C2.3) at similar times. It was found that the immobilized catalysts could be used at ruthenium loadings as low as 0.05 mol %, compared to the model systems where 0.5 mol % ruthenium was required to give favorable results. Complete conversion of 1-octene could be achieved at almost half the time needed when using the model systems as catalyst precursors. The activity of the model systems seems to increase with the increase in steric bulk around the metal center. These model and immobilized systems were also found to cleave styrene affording benzaldehyde in almost quantitative yield in some case (shorter reaction times). The systems, with the siloxane tether via the arene ring, were found to be less active for the cleavage of 1-octene when compared to the above mentioned systems (siloxane tether attached to the imine nitrogen). The immobilized systems IC4.7-IC4.12 performed well compared to their model counterparts, but could not achieve the same conversions at the shorter reaction times as were the case for IC4.1-IC4.6. This lower activity was ascribed to the decreased stability of these systems in solution compared to the above mentioned systems with the tether attached to the imine nitrogen. This was confirmed by monitoring the conversion of the complex (catalyst precursor) to the active species in the absence of substrate (monitored by UV-Vis spectroscopy). It was observed that model complex C3.1 could not be detected in solution after 1 hour, compared to complex C2.2 which was detected in solution even after 24 hours. Experiments were carried out where MCM-41 was added to a solution of model complex C2.2 under typical cleavage reaction conditions. A dramatic increase in the conversion was achieved when compared to a reaction in the absence of MCM-41. An investigation into the effect of the support material on the formation of the expected active species was carried out using UV-Vis spectroscopy. The presence of the active species, RuO4, could be observed at shorter reaction times in the presence of MCM-41. This suggested that the silica support facilitates the formation of the active species from the complex during the reaction, therefore resulting in an increased activity. It was also observed that RuO4 is present in solution in reactions where the immobilized catalyst systems are used after very short reaction times, compared to the prolonged times required for this to occur as is the case for the model systems. Model and immobilized catalysts, C2.1-C2.3 and IC4.1-IC4.6, were also applied as catalysts for the transfer hydrogenation of various ketones. The immobilized systems could be recovered and reused for three consecutive runs before the catalysts became inactive (transfer hydrogenation of acetophenone). Moderate to good conversion were obtained using the immobilized systems, but were found to be less active their model counterparts C2.1-C2.3. / AFRIKAANSE OPSOMMING: Die sintese van `n reeks siloksaan gefunksioneerde Ru(areen)Cl(N,N) komplekse, wat die sintese van nuwe MCM-41 en SBA-15 geimmobiliseerede rutenium(II) katalisatore toelaat, word in hierdie tesis beskryf. Twee ooglopend verskillende metodes is voorgestel om die suksesvolle immobilisering van die siloksaan gefunksioneerde komplekse te bereik. Die kondensasie van die siloksaan gefunksioneerde komplekse, C2.4-C2.6 (siloksaan ketting geheg aan die imien stikstof) en C3.5-C3.7 (siloksaan ketting geheg aan die areen ligand), met die oppervlak silanol groepe van die silika materiale MCM-41 en SBA-15, laat die sintese van geimmobiliseerde katalisatore IC4.1-IC4.6 (siloksaan ketting geheg aan die imien stikstof) en IC4.7-IC4.12 (siloksaan ketting geheg aan die areen ligand) toe. Model en siloksaan gefunksioneerde komplekse C2.6-C2.6 is berei deur die reaksie tussen Schiff basis ligande, L2.1-L2.6, en die [Ru(p-simeen)2Cl2]2 dimeer. `n Tweede, nuwe benadering wat die sintese van komplekse met die siloksaan ketting geheg aan die areen ligand behels, is ook gevolg. Kationiese areen gefunksioneerde Ru(areen)Cl(N,N) komplekse, C3.1-C3.4, is berei deur die N,N ligande rondom die metaal sentrum te wissel vanaf bipiridien tot `n reeks diimien ligande met propiel of diisopropielfeniel substituente by die imien stikstof. Hierdie propanol gefunksioneerde komplekse is met 3-(triëtoksiesiliel)propiel-isosianaat gereageer om sodoende die uretaan gekoppelde siloksaan gefunksioneerde komplekse C3.5-C3.8 op te lewer. Al die komplekse is ten volle gekaraktariseer deur van FT-IR spektroskopie, KMR (1H and 13C) spektroskopie, ESI-MS analise en mikroanalise gebruik te maak. In die geval van model kompleks C3.1, is `n kristalstruktuurbepaling ook uitgevoer. Die heterogene katalisatore, IC4.1- IC4.12, is gekaraktariseer deur poeier X-straaldiffraksie, skandeer- en transmissieelektronmikroskopie, termogravimetriese analise (TGA), induktief gekoppelde plasma optiese emissie spektroskopie (IKP-OES) en BET oppervlak analises, om net `n paar te noem. IKP-OES het ons toegelaat om `n direkte vergelyking te tref tussen die model en geimmobiliseerde sisteme tydens die katalise reaksies. Model komplekse C2.1-C2.3 en C3.1-C3.3, sowel as hul geimmobiliseerde eweknieë IC4.1- IC4.12, is vir die oksidatiewe splyting van alkene (1-okteen en stireen) getoets. Die voorgestelde aktiewe spesie wat tydens hierdie reaksie gevorm word, RuO4, is bevestig deur van UV-Vis spektroskopie gebruik te maak. Oor die algemeen is dit gevind dat aldehied oorheersend gevorm word by laer omsetting. Wanneer die reaksietyd verleng is, is daar gevind dat die aldehied na die ooreenstemmende karboksielsuur omgeskakel is. Wanneer die geimmobiliseerde katalisatore gebruik is tydens die oksidatiewe splitsing van 1-okteen, het die sisteme, met die ketting geheg aan die imien stikstof, deurgangs beter as die model sisteme gevaar. Hoër omskakelings van 1-okteen en hoë selektiwiteite vir heptaldehied is behaal wanneer die geimobiliseerded katalisatore IC4.1-IC4.6 met die nie-geimmobiliseerde model sisteme (C2.1- C2.3) vergelyk is by dieselfde reaksietye. Die geimobiliseerde sisteme kon by rutenium beladings van so laag as 0.05 mol % gebruik word. Dit is in teenstelling met die model sisteme waar 0.5 mol % rutenium nodig was om die reaksie suksesvol te laat plaasvind. Die totale omskakeling van 1-okteen is bereik in die helfte van die tyd wat nodig was wanneer die model sisteme gebruik is. Dit is gevind dat die aktiwiteit van die model sisteme toeneem met `n toename in die steriese grootte van die ligand rondom die metaal. Beide die model en geimmobilseerde sisteme kon ook gebruik word vir die oksidatiewe splyting van stireen. Bensaldehied kon in kwantitiewe opbrengs gevorm word in sommige gevalle. `n Laer aktiwiteit vir die oksidatiewe splyting van 1-okteen is vir die sisteme waar die siloksaan ketting aan die areen ligand geheg is, waargeneem. Hoewel die geimmobiliseerde sisteme IC4.7-IC4.12 beter as hul model eweknieë gevaar het, kon die aktiwiteite wat met IC4.1-IC4.6 bereik is nie geewenaar word nie. Hierdie laer aktiwiteit is toegeskryf aan die verlaagde stabiliteit van dié sisteme in oplossing in vergelyking met IC4.1-IC4.6 (ketting geheg aan die imine stikstof). Die stabiliteit van beide sisteme is getoets deur die omskakeling van die model komplekse (C2.2 en C3.1; katalise voorgangers) na die aktiewe spesie te monitor (UV-Vis spektroskopie). Na 1 uur kon die model kompleks C3.1 nie meer in die oplossing waargeneem word nie. In teenstelling kon model kompleks C2.2 nog selfs na 24 uur in die oplossing bespeur word. Om die rol van die silika materiale tydens die reaksie te ondersoek, is `n eksperiment uitgevoer waar MCM-41 by `n oplossing van kompleks C2.2 gevoeg is. `n Toename in die omskakeling van 1-okteen is waargeneem in vergelyking met `n reaksie waar geen silika teenwoordig was nie. UV-Vis spektroskopie is gebruik om die invloed van die silika op die vorming van die aktiewe spesie te ondersoek. In eksperimente waar MCM-41 teenwoordig was, kon die aktiewe spesie, RuO4, by baie korter reaksietye waargeneem word. Dit wil blyk of die silika materiaal die vorming van die aktiewe spesie vanaf die kompleks aanhelp en sodoende `n toename in die spoed van die reaksie bewerkstellig. RuO4 kon ook by baie korter reaksietye waargeneem word wanneer die geimmobiliseerde sisteme gebruik is. Beide model en geimmobiliseerde sisteme, C2.1-C2.3 en IC4.1-IC4.6, is getoets vir die oordrag hidrogenering van verskilende ketone. Dit was moontlik om die geimmobiliseerde sisteme drie keer te herwin en vir daaropvolgende reaksies te gebruik. Vir die geimmobiliseerde sisteme kon egter slegs gemiddelde omskakelings verkryg word en het swakker gevaar as hul model ekwivalente sisteme, C2.1-C2.3.

Host organisms evolved antiviral responses, which can recognize the viral infection and deal with it. One of the frequent signs of viral infection in a cell is appearance of double-stranded RNA (dsRNA). One of the pathways responding to dsRNA is RNA interference (RNAi), which functions as the key antiviral defence system in invertebrates and plants. Mammals, however, utilize for antiviral defence a different dsRNA-sensing pathway called the interferon response. RNAi functions only in mammalian oocytes and early embryonal stages although its enzymatic machinery is present in all somatic cells, where it is employed in the microRNA pathway. A previous study indicated that the functionality of RNAi in mouse oocytes functions due to an oocyte-specific isoform of protein Dicer (DicerO ), which is truncated at the N-terminus. In my thesis, I aimed to assess whether DicerO processes RNAi substrates more efficiently in vitro than the full-length Dicer (DicerS ), which is found in somatic cells. Therefore, I developed Dicer purification protocol for obtaining both recombinant mouse Dicer isoforms of high purity. I examined their activity in a non-radioactive cleavage assay using RNA substrates with structural features characteristic of RNAi substrates. My results suggest that recombinant DicerO and DicerS do not...