Le contrôle du biofouling sur des surfaces inertes immergées ou en atmosphère humide est une nécessité dans le secteur marin, tant pour des raisons économiques qu’environnementales. La formation de biofilm microbien, étape préalable à la formation du biofouling, est souvent intrinsèquement liée chez les bactéries au système de communication “Quorum Sensing” (QS). Chez certaines bactéries Gram négatif, le QS est basé sur la perception de petites molécules diffusibles appelées N- Acyl Homosérine Lactones (AHLs). L’une des stratégies antifouling en voie de développement de nos jours repose sur l’inhibition du QS bactérien. L’objectif de cette thèse est d’utiliser certaines bactéries marines afin d’identifier des molécules anti-QS capables de perturber la formation de biofilm. Ce travail a donc porté sur la mise en évidence de molécules AHLs impliquées dans le QS chez certaines bactéries marines isolées de la rade de Toulon, l’étude de la modulation de certains phénotypes dont la formation du biofilm, par ces molécules et, la mise en place d’un test préliminaire d’inhibition du QS. Parmi les trois bactéries isolées de la rade de Toulon (TC8, TC14 et TC15) du genre Pseudoalteromonas, connues pour produire de nombreuses molécules actives, et testées pour leur capacité à sécréter des AHLs, seule Pseudoalteromonas sp. TC15 a produit la C12-HSL. P. ulvae TC14, capable de produire un biofilm conséquent et de la violacéine, ne produit aucune AHL. Afin d’évaluer la possibilité d’utiliser une bactérie marine comme outil de criblage anti-QS, interférant avec les AHLs et les conséquences sur son biofilm, des AHLs exogènes ont été testées sur la production de violacéine, la formation de biofilm et la mobilité de TC14. Certaines AHLs ont montré qu’elles pouvaient réguler la production de violacéine et la formation de biofilm chez TC14, suggérant l’existence d’un récepteur AHLs fonctionnel. Des tests préliminaires d’inhibition du QS ont été effectués avec des molécules commerciales et des analogues synthétiques. La 3-oxo-C6-HSL commerciale, ainsi que l’esculétine et la p- benzoquinone, connues pour interférer avec le QS bactérien, ont été capables d’inhiber la production de violacéine ainsi que la formation de biofilm de TC14 à des concentrations n’affectant pas sa croissance. Cette étude suggère donc que P. ulvae TC14 pourrait être utilisée comme un outil de recherche de molécules anti-QS en conditions proches de celles trouvées dans l’environnement marin, et ce dans le but d’être ultérieurement testées sur la formation de biofilm. L’objectif à plus long terme reste de trouver un moyen de limiter la formation du biofilm en utilisant des molécules non toxiques pour l’environnement. / The biofouling control on immersed inert surfaces or in moist atmosphere is a necessity in the marine sector for both economic and environmental reasons. Microbial biofilm formation, the initial step of biofouling development, is intrinsically linked to the communication system “Quorum sensing” (QS). In some Gram negative bacteria, QS is based on the perception of small diffusible signaling molecules called Acyl Homoserine Lactones (AHLs). The inhibition of bacterial QS is part of the different antifouling strategies currently developed. This present work focused on the detection of AHLs molecules involved in this communication system in bacteria isolated from Toulon harbor and the study of modulation of some phenotypes, including biofilm formation, by these molecules as well as the development of a preliminary anti-QS assay. Three marine bacteria isolated from Toulon harbor (TC8, TC14 and TC15), belonging to the Pseudoalteromonas genus, known to synthesize many active molecules, have been tested for their ability to produce AHLs. Only Pseudoalteromonas sp. TC15 produced the C12-HSL. P. ulvae TC14 a violacein-producing and biofilm-forming bacteria, did not secrete any AHLs. Few marine bacteria are used as an anti-QS screening tool, especially by interfering with AHLs with the goal of studying the consequences on biofilm formation. In order to evaluate the possibility to use TC14 with this purpose, exogenous AHLs were tested on the violacein production, the biofilm formation and the motility of TC14. Some AHLs were able to regulate violacein production and biofilm formation suggesting the presence of a functional AHLs receptor in TC14. Preliminary QS inhibition assays were performed with commercial molecules and synthetic analogues. The commercial 3-oxo-C6-HSL as well as esculetin and p-benzoquinone, known to interfere with bacterial QS, were able to inhibit QS and biofilm formation at a non-toxic concentration. Overall, this study suggests that the marine strain P. ulvae TC14 may be used as a tool for the detection of anti-QS molecules in conditions closed to the marine environment. These molecules may subsequently be tested on the biofilm formation of marine bacteria. The long term objective is to find a way to limit biofilm formation, using non-toxic molecules for the environment.

Th. Ph. D.--Sociologie--Augsburg university, 1990.

Root branching allows plants to explore rhizosphere, to gain efficiently water, mineral nutrients or enter in various biotic interactions. Initiation of lateral root formation is localized to pericycle cells, flanking the xylem poles of diarch vascular bundle in Arabidopsis thaliana. Right in these pericycle cells, there is the expression pattern of the gene trap line MGT180. In this theseis , I have provided the evidence that the expression pattern of MGT180 is related with AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED18 (AHL18; At3g60870). AHL18 belongs to a gene family of 29 transcriptional factors of Arabidopsis. AHL18 has not been functionally characterized yet, the analysis of singlemutant ahl18 and some others revealed no significant phenotype. However, one of doublemutants, E15, showed a significant phenotype. This phenotype was evident mainly in the aboveground part of plants, and was not corresponding to any phenotype of AHL mutation described so far. There is a known redundancy among some AHL genes, confirmed by crossing of ahl18 and ahl28 leading to E15 plant. Translation phusion AHL18-mRUBY and AHL22-mRUBY under native promotors should reveal, where these two related proteins act, and if they fiction in autonomous manner or not. Key words Arabidopsis thaliana, lateral root, AHL, pericycle

This thesis is divided into four sections. The first chapter deals with Mamlūk historiography and its major characteristics, alongside an examination of the life al' Aynī's, who was one of the most prominent historians of the period. Special attention is paid to his professions, masters, students as well as his numerous works. Chapter two, on the other hand, focuses on the copies of 'Iqd al-jumān fi tārīkh ahl al-zamān, mentioning the published volumes that covered most of the Ayyūbid and Mamlūk eras. The rest of this chapter deals with the methodology used in the edition of Volume eleven (431-520/1040-1126) as well as demonstrating its importance and sources. Chapter three presents an edition of the Arabic text of Volume eleven. Chapter four is a separate volume, which initially deals with the life and works of the historian Muḥammad b. 'Abd al-Malik al-Hamadhānī. The rest of chapter examines the historical fragments from his lost historical book, called 'Unwān al-siyar fī maḥāsin ahl al-Badū wa'-l Ḥaḍr, also known as Al-Ma'ārif al-muta'akhkhira: these fragments are to be found in Volume eleven of the 'Iqd al-jumān. At the end of this chapter, the Arabic text is reconstructed and its biographical materials, are reorganised in alphabetical order.

No description available.

Kandidatarbetet syftar till att rita en tillbyggnad till Nationalmuseum i Stockholm. Museets nuvarande lokaler ska inom en snar framtid omorganiseras, de verksamheter (konservering, forskning, adminstration etc) som idag är förlagda till huvudbyggnaden ska placeras i en tillbyggnad. Den nuvarande tillbyggnaden (annexet) ska rivas. Tillbyggnaden i detta kandidatprojekt, är placerad på Nationalmuseums baksida. En mindre huskropp i fyra våningar agerar huvudsakligt fasadmotiv och innehåller lastintag och entré på gatuplan, studiesal och referensbibliotek på plan 2 och kontor på plan 3 och 4. Denna volym ligger parallellt med Nationalmuseum. I en svag vinkel ligger en lång och låg huskropp som innehåller konserveringsateljéerna. Denna volym ligger parallellt med Blaisieholmens kvarterssystem. Den låga volymen är helt stängd mot söder, med en traditionellt murad stenmur ytterst. Denna stenmur ramar tillsammans med Nationalmuseums nordostfasad och en länkande kolonnad in platsen bakom Nationalmuseum och riktar den in i sig själv och ut mot vattnet. Platsen som bildas i mellanrummet mellan originalbyggnaden och tillbyggnaden blir en skulpturpark, avsedd att förevisa reproduktioner av Nationalmuseums skulpturala verk. Platsen blir också en identitetsskapande plats i centrala Stockholm riktad mot stadens andra stora konstmuseum, Moderna Museet på Skeppsholmen. / The aim of the work is to design an extension to The National Museum in Stockholm. The current facilities are going to be reorganized in a near future. Conservation of artworks, research and administration, today housed in the museum building, will be moved to an extension. The current addition, built in the 1960s will be torn down. The extension designed in this work is placed behind (north of) The National Museum. A smaller body of four stories act as prime motif and include entrances, offices, research rooms, library and main vertical communication of the extension. This volume lies parallel to the original building. In a small angle to the first body a lower but very elongated volume lies, it is a continuation of the apparent urban grid. It includes the conservation studios and forms a solid granite wall toward the National Museum and the sculpture park created between them. The park becomes a new, identifiable space in the city, in a way targeting the modern museum of art across the water.

Le « quorum sensing » (QS) est un moyen de communication bactérienne impliquant des petites molécules appelées auto-inducteurs qui au-delà d’un certain seuil de concentration induisent une synchronisation de l’expression génétique au sein de la communauté bactérienne. Ce mécanisme est impliqué dans plusieurs processus bactériens tels que la luminescence, la formation du biofilm, ce qui en fait une cible privilégiée pour l’inhibition du biofilm bactérien nuisible aux activités humaines. Plusieurs systèmes QS ont été identifiés ; les plus étudiés sont le système AHL (acyl homoserine lactone) et le système AI2 (auto inducteur 2). L’objectif principal de cette thèse est de caractériser le(s) système(s) QS de Shewanella woodyi, une bactérie marine luminescente capable de coloniser rapidement une surface et de former un biofilm. L’utilisation de biosenseurs de référence et des expériences de LC-MS ont montré que S. woodyi synthétise la C8-HSL et l’AI2. La mutation des gènes impliqués dans la synthèse ou la détection des HSL abolit la luminescence mais n’affecte pas la formation du biofilm. De plus, le système AI2 ne semble pas impliqué dans la luminescence et la formation de biofilm de S. woodyi. L’absence d’un récepteur d’AI2 suggère que cette molécule n’a pas un rôle régulateur et qu’elle ne serait qu’un produit secondaire du métabolisme cellulaire. Ce travail a donc permis de caractériser les 2 principaux systèmes QS de S. woodyi et pourrait permettre d’en faire un nouveau biosenseur marin. / Quorum sensing (QS) is a bacterial communication system involving small molecules called autoinducers which above a threshold concentration, induce the synchronization of genes expression within the bacterial community. This mechanism is involved in several bacterial processes such as luminescence and biofilm formation, making it a preferred target for the inhibition of bacterial biofilm harmful to human activities. Several QS systems have been identified; the most studied ones are the AHL system (acylhomoserine lactone) and the AI2 system (autoinducer 2). The main objective of this thesis is to characterize the QS system (s) of Shewanella woodyi, a luminescent marine bacterium able to rapidly colonize a surface and form a biofilm. The use of reference biosensors and LC-MS experiments have shown that S. woodyi synthesizes C8-HSL and AI2. The mutation of the genes involved in the synthesis or detection of HSL abolishes luminescence but does not affect the biofilm formation. Moreover, the AI2 system does not appear to be involved in the luminescence and biofilm formation of S. woodyi. The absence of an AI2 receptor suggests that this molecule does not have a regulatory role and that it is only a secondary product of cellular metabolism. This work has allowed the characterization of the 2 main QS systems of S. woodyi, which could make this strain a new marine biosensor.

Contemporary north-west Bangladesh is the scene of a religious contest between the self-described 'Hanafis‘, who include various expressions of Islamic faith and practice, and Salafi reformist groups known as Ahl-i-Hadith. Occasionally labelled 'Wahhabis‘ due to their affinity with the doctrine from Arabia, the Ahl-i-Hadith actively seek to purify local Islam of all practices which they consider to be bidaʿ. Local Hanafi Muslims, who form a majority, are resistant to these efforts at total religious reform. This thesis investigates the contemporary discourse taking place between these two communities in Rajshahi, Bangladesh, and between these groups and their authoritative Islamic texts. The case study used to focus on inter-group debates is the contested issue of whether or not to perform rituals meant to assist the dead during al-barzakh – the conscious waiting period in the grave believed to last from death until the day of resurrection. Especially during a soul‘s first forty days in al-barzakh, the Hanafi community observes rituals intended to reduce the torment of the grave and send soʾab, or merit, to the account of the deceased. Participant observation at numerous milad, chollisha and khotom ceremonies for the dead, as well as interviews with local ʿulamaʾ and other informants highlight the progress of Ahl-i-Hadith reform efforts, but also the way in which Hanafi leaders defend and interpret their 'unorthodox‘ practices using authoritative Sunni hadith and Qurʾanic passages. Additional Islamic texts which are locally influential are examined. Special voice is given to "what Muslims say" in an attempt to let the words and actions of those involved in the debates direct the research agenda as they interpret and defend their respective positions. This thesis provides other researchers with a field-based account of contemporary Islamic belief and practice in Bangladesh – an understudied Islamic context containing over 150 million people. Dozens of quotations from ʿulamaʾ are reproduced in the original Bengali and in English. Additionally, this study complicates Islamic fundamentalist and Western scholarly conceptions of 'popular Islam‘ and 'syncretism‘ by showing that Hanafi ʿulamaʾ in Rajshahi explain their (contested) beliefs and activities in Islamic terms, using universally recognised Sunni sources of authority, especially the hadith literature.

Traditional bacterial disease therapies utilize compounds that ultimately kill the target bacteria but it exerts a strong selective pressure on the bacteria to develop multi-drug resistance mutants. The increasing occurrence of resistance in common pathogens has highlighted the need to identify new anti-microbials that target the control of bacterial pathogenicity in a non-extermination manner to reduce the incidence of bacteria resistance. One new strategy exploits the discrete signaling molecules that regulate the various bacterial signaling pathways, which are responsible for the expression of pathogenicity traits. Halogenated furanones (fimbrolides) from the marine red alga, Delisea pulchra have been shown to interfere with the key signaling pathway present in Gram-negative bacteria by competitively displacing the cognate signaling molecule from the transcription protein. This project focused on the design and synthesis of 1,5-dihydropyrrol-2-ones, a new class of fimbrolide derivatives capable of displaying strong antagonistic properties of the fimbrolides. Primary synthetic methodologies examined include the halolactamization of allenamides and the direct lactone-lactam transformation. No doubt, both methodologies yielded the lactam ring, the former failed to introduce the crucial C-5 bromomethylene group essential for bioactivity. A facile high yielding two-step lactone-lactam transformation method was developed and using this method, a wide range of substituted 5-bromomethyl- and 5-dibromomethylene-1,5-dihydropyrrol-2-ones were synthesized. Furthermore, a new class of tricyclic crown-ether type compounds with no literature precedent were discovered. To vary the diversity of the compounds, a related class of compounds, 5,6-dihydroindol-2-ones, were examined. A general versatile method for the synthesis of 7-substituted 5,6-dihydroindol-2-ones was developed. The synthetic strategy proceeds via the established Suzuki-Miyaura cross-coupling reaction of halogenated dihydroindol-2-ones with arylboronic acids/esters. The Suzuki methodology was found to be reliable in furnishing a wide range of 7-substituted products in high yields. A preliminary molecular modeling approach was used to assist in the design of new anti-microbials via the ligand-docking analyses of the TraR and LasR protein. A positive correlation was observed between the docking scores and biological activity and the methodology was further developed into an initial screening tool to filter potential active and non-active compounds. The newly synthesized compounds were analysed for their efficacy in reducing the expression of the Green Fluorescent Protein (GFP) in the presence of natural AHL signaling molecules in an AHL-monitor strain, indicative of the inhibition of bacterial phenotype expression. The dihydropyrrol-2-one class of compounds showed significant biological activity and this highlighted their potential for further development.

Quorum sensing (QS) cell-cell communication systems are utilized by bacteria to coordinate their behaviour according to cell density. Several different types of QS signal molecules have been identified, among which acyl-homoserine lactones (AHLs) produced by Proteobacteria have been studied to the greatest extent. QS has been shown to be involved in many aspects of bacterial life, including virulence, bioluminescence, symbiosis, antibiotic production, swarming and swimming motility, biofilm formation, conjugation and growth inhibition. Although QS has been studied extensively in cultured microorganisms, little is known about the QS systems of uncultured microorganisms and the roles of these systems in microbial communities. To extend our knowledge of QS systems and to better understand the signalling that takes place in the natural environment, in the first part of this thesis, isolation and characterization of new QS systems from metagenomic libraries constructed using DNA from activated sludge and soil were described. Using an Agrobacterium biosensor strain, three cosmids (QS6-1, QS10-1 and QS10-2) that encode the production of QS signals were identified and DNA sequence analysis revealed that all three clones encode a novel luxI family AHL synthase and a luxR family transcriptional regulator. Thin layer chromatography revealed that these LuxI homolog proteins are able to synthesize multiple AHL signals. Tandem mass spectrometry analysis revealed that LuxIQS6-1 directs the synthesis of at least three AHLs, 3-O-C14:1 HSL, 3-O-C16:1 HSL and 3-O-C14 HSL; LuxIQS10-1 directs the synthesis of at least 3-O-C12 HSL and 3-O-C14 HSL; while LuxIQS10-2 directs the synthesis of at least C8 HSL and C10 HSL. Two possible new AHLs, C14:3 HSL and (?)-hydroxymethyl-3-O-C14 HSL, were also found to be synthesized by LuxIQS6-1. Agrobacterium tumefaciens is a plant pathogen that causes crown gall disease. Its ability to transfer and integrate foreign DNA into plant genome also makes it a useful tool for plant genetic engineering. Ethylene, the gaseous plant hormone, has been reported to be important for both crown gall development and A. tumefaciens mediated transformation efficiency to plants. ACC deaminase, an enzyme that can break down ACC, the direct precursor of ethylene biosynthesis in plants, is a mechanism used by some plant growth promoting bacteria (PGPB) to promote plant growth by reducing stress ethylene levels. In the second part of this thesis, the effect of ACC deaminase on A. tumefaciens induced crown gall development and on A. tumefaciens mediated transformation efficiency was studied. By either introduction of an ACC deaminase encoding gene into the virulent strain A. tumefaciens C58 or co-inoculation of A. tumefaciens C58 with an ACC deaminase containing PGPB P. putida UW4, using different plant systems including tomato plants and castor bean plants, it was found that the presence of an ACC deaminase significantly inhibited crown gall development. It was also found that introduction of an acdS gene into the disarmed A. tumefaciens strain GV3101::pMP90 reduced the ethylene levels evolved by plants during infection and cocultivation process and increased the transformation efficiency of commercialized canola cultivars. The A. tumefaciens D3 strain was reported to contain an ACC deaminase encoding gene (acdS). In this study it was determined that this strain is an avirulent strain and shows plant growth promoting activity. When co-inoculated with A. tumefaciens C58 on castor bean stems, both the wild type and the acdS knockout mutant showed biocontrol activity and were able to significantly inhibit crown gall formation, with the wild type strain showing slightly better tumor inhibition effects. The mutation of acdS and its regulatory gene lrpL in A. tumefaciens D3 was also found to affect QS signal production of this strain, which indicates a cross talk between the two sets of genes.