La surexpression de pompes d'efflux par les cellules cancéreuses permet l'élimination d'agents cytotoxiques, induisant alors une résistance à la chimiothérapie. Trois transporteurs ABC sont principalement impliqués dans cette résistance : ABCB1 (aussi appelé P-gp), ABCC1 (ou MRP1) et ABCG2 (ou BCRP, MXR, ABCP). Du fait de leur implication dans le phénotype de " MultiDrug Resistance ", il est essentiel de mieux comprendre le fonctionnement de ces transporteurs. Une étude par mutagenèse dirigée a montré que les boucles intracellulaires, ICL0 et ICL1 sont impliquées dans le transport des substrats. Deux résidus sont particulièrement intéressants : W379 qui agirait comme un filtre des substrats ; et H457 qui participerait à la reconnaissance ou à la fixation des substrats. Par ailleurs, il est important de moduler cette chimiorésistance. Dans ce contexte nous avons développé une nouvelle classe d'inhibiteurs d'ABCB1 et ABCG2 non compétitifs basés sur un motif dipeptidique. Les composés les plus efficaces, CT1347 pour ABCB1 et CT1364 pour ABCG2, s'avèrent, d'une part peu ou pas cytotoxiques à fortes concentrations, abolissent d'autre part la résistance induite par ABCB1 ou ABCG2 et se comportent comme des inhibiteurs non compétitifs du Hoechst 33342 et de la daunorubicine. De plus, CT1364 inhibe l'activité ATPasique d'ABCG2 et induit une diminution rapide de l'expression de la protéine. Enfin, les 1ers tests in vivo de ce composé montrent que l'association avec l'irinotécan ralentit la croissance des xénogreffes de petite taille chez des souris

In Streptococcus pyogenes, the protein SiaA (HtsA) is part of a heme uptake pathway system and involved in heme transfer from Shp to the ABC transporter. SiaA mutants, in which alanine replaces the axial histidine (H229) and methionine (M79) ligands, as well as a lysine (K61) and cysteine (C58) located near the heme propionates, are reported. Studies on a mutant of a cysteine expected to be at a distance from the propionates (C47A) are also reported. The coordination state and spin state of the selected mutants were determined via Resonance Raman studies. The pKa values of mutants ranged from 9.0 to 9.4, which were close to the pKa of the WT SiaA (9.7). The midpoint reduction potential of lysine (K61A) mutant was determined by spectroelectrochemical titration to be 61 ± 3 mV vs. SHE, similar to the WT protein (68 ± 3 mV). The addition of guanidinium hydrochloride resulted in protein denaturation that could show more than one process and occurred over days. The ease of protein unfolding was directly related to the extent of interaction of the residues with the heme: changes in the axial ligands resulted in far greater changes in heme protein stability than changes in the residues near the heme propionates. The causative agent of diphtheriae, Corynebacterium diphtheriae, imports heme via an ABC uptake transporter. In this research, two of the five proteins in the heme uptake pathway of C. diphtheriae were studied. These proteins were HmuT, lipoprotein component of the ABC transporter, and HtaA, the heme receptor. UV-visible spectroscopy and fluorescence spectroscopy showed that HmuT protein as isolated bound a porphyrin, rather than heme. Electrospray ionization mass spectrometry (ESI-MS) studies suggested that two tetrapyrroles were bound. To assess stability of this protein towards heme release, thermal denaturation studies were performed. For HtaA, UV-visible and fluorescence spectroscopy also showed the protein as isolated was also bound a porphyrin, rather than heme. Homology studies showed that HtaA protein is quiet distant from homologous heme uptake proteins and could be a member of novel heme binding domain family.

Inköpsavdelningen är en viktig del i företag som ansvarar för att artiklar finns tillgängliga när de behövs. Inköps uppgift är att köpa rätt kvantitet av rätt kvalitet i rätt tidpunkt från rätt leverantör till rätt pris. Detta arbete kan underlättas om tydliga riktlinjer för hur inköpsarbete bör bedrivas finns. Swisslog-Accalon AB i Boxholm vill omarbeta sina inköps- och materialplaneringsrutiner, då många av de inköp som görs baseras på inköparens erfarenhet och kunskap om artiklarna samt att många inköp görs mot specifika kranprojekt. Detta har lett till att artiklar i många fall köps utan hänsyn tagen till de mest ekonomiska aspekterna då vanligtvis inga partiformningsmetoder används. Syftet med examensarbetet är att skapa ett ramverk för inköp av standardartiklar till företagets kranproduktion, för att inköpsarbetet på företaget ska underlättas och minskas. För att uppfylla syftet med examensarbetet har fyra frågor arbetats fram: Hur ska standardartiklarna i kranproduktionen klassificeras? Vad ska ingå i de olika emballagekategorierna? Vilka är de ekonomiska behovstäckningstiderna för standardartiklarna i kranproduktionen? Hur ska ramverket användas? Relevant empiri har samlats in med metoder som intervjuer och observationer samt att tillgång till nödvändiga dokument och arkivmaterial har erhållits. Empirin som samlats in har analyserats med litteratur inom det aktuella området. Resultatet av examensarbetet är ett framarbetat ramverk som beskriver hur inköpsarbetet av företagets standardartiklar till kranproduktion rekommenderas att bedrivas. Dessutom kommer ramverket att underlätta och minska inköpsarbetet, då företaget rekommenderas att styra vissa av artiklarna med enkla och tidseffektiva metoder.

Bakgrunden till detta arbete har varit att, på uppdrag av Green Cargo Road&Logistics, finna möjligheter att sänka kapitalbindningen vid Goodyears nordenlager i Norrköping. Lageromsättningshastigheten är i nuläget inte tillfredställande och även en generell minskning av lagernivåerna är önskvärd. En nulägesanalys har genomförts medelst intervjuer och studiebesök. Därefter har en grundlig litteraturstudie och en detaljstudie av ett urval artiklar i lagersystemet utförts. Utifrån dessa båda studier samt utförd problemanalys rekommenderas ett antal förslag på förbättringsåtgärder. Studien visar att lagerstyrningssystemet inte på ett godtagbart sätt klarar av att ta hänsyn till nordenmarknadens säsongsvariationer. Bristsituationer är vanligt förekommande tidigt under säsong samtidigt som överbeställningar sker i slutet på säsong. För dubbade och monterade artiklar kan i många fall höga lagernivåer och låg lageromsättningshastighet observeras, detta beroende på den process förädlingen medför. Ytterligare en faktor som starkt bidrar till komplexiteten är i detta fall det stora antalet artiklar i systemet. Dessutom kan ett stort antal artiklar iakttagas där lagernivåerna ligger relativt högt konstant över såväl hög- som låg säsong, där dessutom omsättningen är låg. Ett antal åtgärdsförslag med rekommendationer föreslås i sex punkter. Åtgärdsförslagen rekommenderar ett lagerstyrningssystem bättre anpassat till nordenmarknadens kraftiga säsongsvariationer. Karaktäristikan med påtagliga säsongsvariationer bidrar till stora prognosfel och lagerstyrningssystemet behöver på ett bättre sätt hantera prognosavvikelserna. Detta inkluderar en reviderad partiformningsmetod, då det nuvarande användandet av metoden TBO inte ger tillfredställande resultat. I dagsläget är förädlingen en flaskhals i lagersystemet, varvid ett införskaffande av högkapacitetsdubbningsmaskiner skulle höja lageromsättningshastigheten. Ytterligare en åtgärd vilken skulle höja lageromsättningshastigheten är en bättre bevakning av inaktuella artiklar. För lågvolymartiklar med avsevärd hög lagernivå i förhållande till prognos bör en översyn utföras och en rutin för övervakning av dessa skapas.

Thesis (M.B.A.)--University of Hong Kong, 1983.

Abstract S. aureus has 16 predicted two-component systems (TCS) that respond to a range of environmental stimuli, and allow for adaptation to stresses. Of these 16, three have no known function, and are not homologous to any other TCS found in closely related organisms. NsaRS is one such element, and belongs to the intramembrane-sensing histidine kinase (IM-HK) family, which is conserved within the Firmicutes. The regulators are defined by a small sensing domain within their histidine kinase, suggesting that they do not sense external signals, but stress in or at the membrane. Our characterization of NsaRS in this work reveals that, as with other IM-HK TCS, it responds to cell-envelope damaging antibiotics, including phosphomycin, ampicillin, nisin, gramicidin, CCCP and penicillin G. Additionally; we reveal that NsaRS regulates a downstream transporter, NsaAB, during nisin-induced stress. Phenotypically, nsaS mutants display a 200-fold decreased ability to develop resistance to another cell-wall targeting antibiotic, bacitracin. Microarray analysis reveals the transcription of 245 genes is altered in a nsaS mutant, with the vast majority down-regulated. Included within this list are genes involved in transport, drug-resistance, cell-envelope synthesis, transcriptional regulation, amino acid metabolism and virulence. Using ICP-MS, a decrease in intracellular divalent metal ions was observed in an nsaS mutant, when grown under low abundance conditions. Characterization of cells using electron microscopy reveals that nsaS mutants also have alterations in cell-envelope structure. Finally, a variety of virulence related phenotypes are impaired in nsaS mutants, including biofilm formation, resistance to killing by human macrophages and survival in whole human blood. Thus NsaRS is important in sensing cell wall damage in S. aureus, and functions to reprogram gene expression to modify cell-envelope architecture, facilitating adaptation and survival. Interestingly, in our microarray analysis, we observed a more than 30-fold decrease in transcription of an ABC transporter, SACOL2525/2526, in the nsaS mutant. This transporter bears strong homology to nsaAB, and is currently uncharacterized. Exploration of the role of SACOL2525/2526 revealed that, along with NsaRS, it too responds to cell-envelope damaging antibiotics. Specifically, its expression was induced by phosphomycin, daptomycin, penicillin G, ampicillin, oxacillin, D-cycloserine and CCCP. Mutation of this transporter results in increased sensitivity to the antibacterial agent daptomycin, and decreased sensitivity to free fatty acids. These findings are perhaps explained by altered membrane fluidity in the mutant strain, as the transporter null-strain is more readily killed in the presence of organic solvents, such as toluene. In addition, SACOL2525/2526 mutants have a decreased ability to form spontaneous mutants in response to several other peptidoglycan synthesis targeting antibiotics, suggesting a role for SACOL2525/2526 in antibiotic resistance. Inactivation of this transporter alters the cell envelope, and produces similar effects to those observed with the nsaS mutant, with increased capsule production, that may provide resistance to lysostaphin. Interestingly, the nsaS microarray revealed that this TCS negatively regulates only 34 genes, including 6 out of the 10 major secreted proteases. Despite a number of reports in the literature describing these enzymes as virulence factors, the data is often conflicting. Therefore, the contribution of proteases to CA-MRSA pathogenesis was investigated, by constructing a strain lacking all 10 extracellular protease genes. Analysis of this strain using murine models of infection reveals secreted proteases significantly impact virulence in both localized and systemic infections. Additionally, inactivation of these enzymes strongly influences survival in whole human blood, and increases sensitivity to antimicrobial peptides. Using a proteomics approach, we demonstrate that the contribution of secreted proteases to pathogenicity is related to differential processing of a large number of surface-associated virulence factors and secreted toxins. Collectively these findings provide a unique insight into the role of secreted proteases in CA-MRSA infections.

This dissertation is devoted to our synthetic studies towards the total synthesis of the natural product Nakadomarin A, and Manzamine A using the Pauson-Khand reaction as the key step. Chapter 1 reviews past work using Pauson-Khand technology. Chapter 2 reviews the N-alkyl piperidine family of natural products. Chapter 3 reviews published total syntheses of Manzamine A and Nakadomarin A. Chapter 4 explores our work using the Pauson-Khand reaction to form the ABC rings of Nakadomarin A and subsequent B ring expansion to form the ABC ring core of Manzamine A. Chapter 5 explores our approaches to the furan portion, as well as, our approaches to the macrocyclic F ring. Finally Chapter 6 contains the description of the experiments performed along with relevant analytical data. / text

Då tillverkningsindustrin går mot en högre grad av kundanpassning och implementering av Lean, samtidigt som föråldrade traditionella kalkyleringsmetoder fortfarande används i moderna industriföretag, är det intressant att utreda relationerna mellan produktionsflöden av kundanpassad karaktär, Lean samt olika kalkyleringsmetoder. Syftet är att öka kostnadsprecisionen i förkalkylen för ett produktionsflöde av kundanpassad och Lean karaktär och beskriva en generaliserbar arbetsprocess för detta. Syftet är även att ta fram generella rekommendationer för val av kalkyleringsmetod genom att utifrån denna produktions karaktär genomföra en jämförande analys av kalkyleringsmetoder (traditionella kalkylmetoder, ABC och kalkylering enligt Lean). Genom en litteraturstudie samt en fallstudie av ett produktionsflöde med många varianter och inslag av Lean har båda syftena uppfyllts. Fallstudien har utförts genom intervjuer och observationer. Problem och positiva faktorer som enligt litteratur karaktäriserar produktion av kundanpassade produkter har även återfunnits på fallföretaget. Det sambandet har kunnat användas för att stödja analysen av relationerna. Relationerna mellan kalkyleringsmetoder, Lean samt produktionsflöden av kundanpassad karaktär har analyserats genom att jämföra litteratur och resultat från fallstudien. Det framkom att Value Stream Costing (VSC) är den mest lämpliga kalkyleringsmetoden för produktionsflöden med kundanpassade produkter som uppnått en hög mognadsgrad av Lean. Förkalkyleringen på fallföretaget är beroende av tillförlitliga operationstider, vilket tagits fram på fallföretaget samtidigt som en generell arbetsprocess utarbetats. Operationstiderna togs i detta fall fram genom videoupptagning av produktionsmomenten samt efterföljande analys i mjukvaran AviX. Genom att följa den generella arbetsprocessen som utarbetats erhålls både ett bra underlag till förkalkylering samt ständiga förbättringar i produktionsflödet. Eftersom forskning visar att Lean bör implementeras i hela organisationen om full fördel med Lean ska uppnås, kan VSC vara en utmärkt kalkyleringsmetod för att komma ifrån föråldrade, traditionella kalkyleringsmetoder samtidigt som denna kalkyleringsmetod förenklar kalkylering i produktion av kundanpassad karaktär. / Since the manufacturing industry is heading for a higher level of customization and implementation of Lean, at the same time as outmoded traditional costing methods is still used in modern industrial organizations, it is interesting to explore the relations between production flows of customized character, Lean and different costing methods. The purpose of this thesis is to increase the cost precision in the preliminary calculation for a product flow of customer adapted and Lean character, and to describe a generalizable work process for this. The purpose is also to develop general recommendations regarding the choice of costing methods by, on a basis of the character of this production, a comparative analysis of costing methods (traditional costing methods, ABC and Lean accounting/VSC). Through a literature study and a case study of a production flow with a high level of variety and influence from Lean, both of the purposes has been fulfilled. The case study has been accomplished through interviews and observations. Problems and positive elements that according to literature characterize the production of customized products have also been found in the case company. That connection has been used to support the analysis of the relations. The relations between costing methods, Lean and production flows of customized character has been analyzed through a comparison between findings in literature and results from the case study. It has been found that Value Stream Costing (VSC) is the most appropriate costing method for production flows of customized products that has reached a high maturity level of Lean. The preliminary costing is dependent on reliable operation times which have been produced on the case study company, while a general work process has been developed. The operation times were in this case identified through video recordings of the production moments and a following analysis in the software AviX. By following the general work process that has been developed, useful material for preliminary costing and continuous improvements in the production flow will be obtained. Since research is showing that Lean should be implemented in the whole organization if full advantages of Lean shall be obtained, VSC is found to be an ideal costing method to replace outmoded, traditional costing methods at the same time as this costing method simplifies costing in production flows of customized character.

Lignin is a key component of plant secondary cell walls, providing strength to the plant and allowing water transport. Lignin is a polymer of monolignols that are synthesized in the cell and transported into the cellulose rich cell wall. The primary goal of this thesis is to understand the mechanism(s) of monolignol deposition during xylogenesis. The currently accepted theory is that monolignols are exported by Golgi-mediated vesicle delivery to the secondary cell wall. When this theory was re-examined using cryofixed developing pine, quantitative autoradiography showed that monolignols did not accumulate in Golgi but were rapidly translocated from cytosol to cell wall. This suggests alternative mechanisms, such as membrane transporters, work in monolignol export. ATP binding cassette (ABC) transporters were chosen because they transport other secondary metabolites and some ABC transporter encoding genes are highly expressed in lignifying cells. Four candidate ABC transporters were selected in Arabidopsis (ABCB11, ABCB14, ABCB15 from the ABCB/MDR subfamily and ABCG33 from the ABCG/PDR subfamily) and shown to have overlapping, high vasculature expression patterns. Mutants with T-DNA insertions in single ABC transporter genes had no change in lignification of inflorescence stems. However, a reduced polar auxin transport phenotype was detected in mutants of ABCB11, ABCB14 and ABCB15. An additional approach was the use of inhibitors of ABC transporters. A new assay, which was developed to quantify lignification in primary xylem of Arabidopsis roots, demonstrated that ABC inhibitors did not change lignin deposition. Monolignols are exported and polymerized in the polysaccharide matrix of the cell wall, which includes hemicelluloses that may organize monolignols during polymerization. Since diverse lignified cell types are enriched in either G- or S-lignin, I hypothesized that this pattern could reflect different hemicellulose distributions, which was examined using antibody labeling of xylans or mannans in hybrid poplar xylem. While xylans were generally distributed in all secondary cell walls, mannans were enriched in fibers but not in the ray and vessel walls. In summary, during secondary cell wall deposition, monolignols are exported by unknown transporter(s) rather than Golgi vesicles. In developing poplar wood, the monolignols are deposited into diverse hemicellulose domains in different cell types.

In 1974, H. Ruderman posed the following question: If $(2^m-2^n)|(3^m-3^n)$, then does it follow that $(2^m-2^n)|(x^m-x^n)$ for every integer $x$? This problem is still open. However, in 2011, M. R. Murty and V. K. Murty showed that there are only finitely many $(m,n)$ for which the hypothesis holds. In this thesis, we examine two generalizations of this problem. The first is replacing 2 and 3 with arbitrary integers $a$ and $b$. The second is to replace 2 and 3 with arbitrary algebraic integers from an imaginary quadratic field. In both of these cases we have shown that there are only finitely many $(m,n)$ for which the hypothesis holds. To get the second result we also generalized a result by Bugeaud, Corvaja and Zannier from the integers to imaginary quadratic fields. In the last half of the thesis we use the abc conjecture and some related conjectures to study some exponential Diophantine equations. We study the Pillai conjecture and the Erd\"{o}s-Woods conjecture and show that they are implied by the abc conjecture and that when we use an effective version, very clean bounds for the conjectures are implied. / Thesis (Ph.D, Mathematics & Statistics) -- Queen's University, 2012-04-13 12:04:14.252